ETH Price: $4,193.55 (-2.62%)
Gas: 0.53 Gwei

Transaction Decoder

Block:
17420541 at Jun-06-2023 09:31:11 AM +UTC
Transaction Fee:
0.00736028204420474 ETH $30.87
Gas Used:
366,049 Gas / 20.10736826 Gwei

Emitted Events:

90 AdminUpgradeabilityProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x0000000000000000000000004814e8edcb3634295a6aee285aa05e8f1bdf3942, 0x000000000000000000000000e66b31678d6c16e9ebf358268a790b763c133750, 000000000000000000000000000000000000000000000075d7d8c3437d4a21c1 )
91 AdminUpgradeabilityProxy.0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925( 0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925, 0x0000000000000000000000004814e8edcb3634295a6aee285aa05e8f1bdf3942, 0x000000000000000000000000e66b31678d6c16e9ebf358268a790b763c133750, ffffffffffffffffffffffffffffffffffffffffffffff8a28273cbc82b5de3e )
92 AdminUpgradeabilityProxy.0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925( 0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925, 0x000000000000000000000000e66b31678d6c16e9ebf358268a790b763c133750, 0x000000000000000000000000def1c0ded9bec7f1a1670819833240f027b25eff, 000000000000000000000000000000000000000000000075d7d8c3437d4a21c1 )
93 FiatTokenProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000f4bffd826c6cf401221afb97f47c1db60d943db8, 0x000000000000000000000000def1c0ded9bec7f1a1670819833240f027b25eff, 00000000000000000000000000000000000000000000000000000000395ff9f4 )
94 AdminUpgradeabilityProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000e66b31678d6c16e9ebf358268a790b763c133750, 0x000000000000000000000000f4bffd826c6cf401221afb97f47c1db60d943db8, 000000000000000000000000000000000000000000000075d7d8c3437d4a21c1 )
95 AdminUpgradeabilityProxy.0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925( 0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925, 0x000000000000000000000000e66b31678d6c16e9ebf358268a790b763c133750, 0x000000000000000000000000def1c0ded9bec7f1a1670819833240f027b25eff, 0000000000000000000000000000000000000000000000000000000000000000 )
96 UniswapV3Pool.Swap( sender=ZeroEx, recipient=ZeroEx, amount0=2173822452631773782465, amount1=-962591220, sqrtPriceX96=52723738563496811755494, liquidity=494143066305261749, tick=-284470 )
97 WETH9.Transfer( src=0x88e6A0c2dDD26FEEb64F039a2c41296FcB3f5640, dst=ZeroEx, wad=529438361257466854 )
98 FiatTokenProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000def1c0ded9bec7f1a1670819833240f027b25eff, 0x00000000000000000000000088e6a0c2ddd26feeb64f039a2c41296fcb3f5640, 00000000000000000000000000000000000000000000000000000000395ff9f4 )
99 0x88e6a0c2ddd26feeb64f039a2c41296fcb3f5640.0xc42079f94a6350d7e6235f29174924f928cc2ac818eb64fed8004e115fbcca67( 0xc42079f94a6350d7e6235f29174924f928cc2ac818eb64fed8004e115fbcca67, 0x000000000000000000000000def1c0ded9bec7f1a1670819833240f027b25eff, 0x000000000000000000000000def1c0ded9bec7f1a1670819833240f027b25eff, 00000000000000000000000000000000000000000000000000000000395ff9f4, fffffffffffffffffffffffffffffffffffffffffffffffff8a70e9d92c8a41a, 0000000000000000000000000000000000005ba23a268e840f883bf2c6e74ec9, 000000000000000000000000000000000000000000000001942ac4ce15034b10, 0000000000000000000000000000000000000000000000000000000000031235 )
100 AdminUpgradeabilityProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000e936f0073549ad8b1fa53583600d629ba9375161, 0x000000000000000000000000e66b31678d6c16e9ebf358268a790b763c133750, 000000000000000000000000000000000000000000000015c0c6b20bd0164589 )
101 WETH9.Transfer( src=ZeroEx, dst=0xE936f0073549AD8b1fA53583600d629Ba9375161, wad=529438361257466854 )
102 0xe936f0073549ad8b1fa53583600d629ba9375161.0xc42079f94a6350d7e6235f29174924f928cc2ac818eb64fed8004e115fbcca67( 0xc42079f94a6350d7e6235f29174924f928cc2ac818eb64fed8004e115fbcca67, 0x000000000000000000000000def1c0ded9bec7f1a1670819833240f027b25eff, 0x000000000000000000000000e66b31678d6c16e9ebf358268a790b763c133750, ffffffffffffffffffffffffffffffffffffffffffffffea3f394df42fe9ba77, 0000000000000000000000000000000000000000000000000758f1626d375be6, 00000000000000000000000000000000000000000940a74441dab8ece072b454, 00000000000000000000000000000000000000000000299223086adbe67e1924, fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffefc97 )
103 AdminUpgradeabilityProxy.0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef( 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef, 0x000000000000000000000000e66b31678d6c16e9ebf358268a790b763c133750, 0x0000000000000000000000004814e8edcb3634295a6aee285aa05e8f1bdf3942, 000000000000000000000000000000000000000000000015c0c6b20bd0164589 )

Account State Difference:

  Address   Before After State Difference Code
0x2a3bFF78...a3dC00e34
(Coinbase: MEV Builder)
0.070320883405408516 Eth0.071052981405408516 Eth0.000732098
0x4814E8Ed...F1BDF3942
0.034754206573026815 Eth
Nonce: 66
0.027393924528822075 Eth
Nonce: 67
0.00736028204420474
0x6De037ef...27e4Aeb24
0x88e6A0c2...FcB3f5640
(Uniswap V3: USDC 3)
0xA0b86991...E3606eB48
0xC02aaA39...83C756Cc2
0xE936f007...Ba9375161
(Uniswap V3: RNDR 2)
0xF4bfFD82...60D943db8
(Uniswap V3: WILD-USDC 2)

Execution Trace

ZeroExProxy.proxiedSwap( msgData=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feeToken=0x2a3bFF78B79A009976EeA096a51A948a3dC00e34, inputToken=0x2a3bFF78B79A009976EeA096a51A948a3dC00e34, inputAmount=2173822452631773782465, outputToken=0x6De037ef9aD2725EB40118Bb1702EBb27e4Aeb24, fee=0 )
  • AdminUpgradeabilityProxy.23b872dd( )
    • ZeroDAOToken.transferFrom( sender=0x4814E8Edcb3634295A6AeE285Aa05e8F1BDF3942, recipient=0xe66B31678d6C16E9ebf358268a790B763C133750, amount=2173822452631773782465 ) => ( True )
    • AdminUpgradeabilityProxy.dd62ed3e( )
      • ZeroDAOToken.allowance( owner=0xe66B31678d6C16E9ebf358268a790B763C133750, spender=0xDef1C0ded9bec7F1a1670819833240f027b25EfF ) => ( 0 )
      • AdminUpgradeabilityProxy.dd62ed3e( )
        • ZeroDAOToken.allowance( owner=0xe66B31678d6C16E9ebf358268a790B763C133750, spender=0xDef1C0ded9bec7F1a1670819833240f027b25EfF ) => ( 0 )
        • AdminUpgradeabilityProxy.095ea7b3( )
          • ZeroDAOToken.approve( spender=0xDef1C0ded9bec7F1a1670819833240f027b25EfF, amount=2173822452631773782465 ) => ( True )
          • ZeroEx.0f3b31b2( )
            • MultiplexFeature.multiplexMultiHopSellTokenForToken( tokens=[0x2a3bFF78B79A009976EeA096a51A948a3dC00e34, 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2, 0x6De037ef9aD2725EB40118Bb1702EBb27e4Aeb24], calls=, sellAmount=2173822452631773782465, minBuyAmount=389234433070005653568 ) => ( boughtAmount=401272611412376962441 )
              • AdminUpgradeabilityProxy.70a08231( )
                • RenderToken.balanceOf( _owner=0xe66B31678d6C16E9ebf358268a790B763C133750 ) => ( 0 )
                • ZeroEx.168a6432( )
                  • UniswapV3Feature._sellTokenForTokenToUniswapV3( encodedPath=0x2A3BFF78B79A009976EEA096A51A948A3DC00E34000BB8A0B86991C6218B36C1D19D4A2E9EB0CE3606EB480001F4C02AAA39B223FE8D0A0E5C4F27EAD9083C756CC2, sellAmount=2173822452631773782465, minBuyAmount=0, recipient=0xDef1C0ded9bec7F1a1670819833240f027b25EfF, payer=0xe66B31678d6C16E9ebf358268a790B763C133750 ) => ( buyAmount=529438361257466854 )
                    • UniswapV3Pool.swap( recipient=0xDef1C0ded9bec7F1a1670819833240f027b25EfF, zeroForOne=True, amountSpecified=2173822452631773782465, sqrtPriceLimitX96=4295128740, data=0x0000000000000000000000002A3BFF78B79A009976EEA096A51A948A3DC00E34000000000000000000000000A0B86991C6218B36C1D19D4A2E9EB0CE3606EB480000000000000000000000000000000000000000000000000000000000000BB8000000000000000000000000E66B31678D6C16E9EBF358268A790B763C133750 ) => ( amount0=2173822452631773782465, amount1=-962591220 )
                      • FiatTokenProxy.a9059cbb( )
                      • AdminUpgradeabilityProxy.70a08231( )
                      • ZeroEx.fa461e33( )
                      • AdminUpgradeabilityProxy.70a08231( )
                      • Uniswap V3: USDC 3.128acb08( )
                        • WETH9.transfer( dst=0xDef1C0ded9bec7F1a1670819833240f027b25EfF, wad=529438361257466854 ) => ( True )
                        • FiatTokenProxy.70a08231( )
                        • ZeroEx.fa461e33( )
                        • FiatTokenProxy.70a08231( )
                        • ZeroEx.4a931ba1( )
                          • UniswapV3Feature._sellHeldTokenForTokenToUniswapV3( encodedPath=0xC02AAA39B223FE8D0A0E5C4F27EAD9083C756CC20027106DE037EF9AD2725EB40118BB1702EBB27E4AEB24, sellAmount=529438361257466854, minBuyAmount=0, recipient=0xe66B31678d6C16E9ebf358268a790B763C133750 ) => ( buyAmount=401272611412376962441 )
                            • Uniswap V3: RNDR 2.128acb08( )
                              • AdminUpgradeabilityProxy.a9059cbb( )
                              • WETH9.balanceOf( 0xE936f0073549AD8b1fA53583600d629Ba9375161 ) => ( 823889052243360165423 )
                              • ZeroEx.fa461e33( )
                              • WETH9.balanceOf( 0xE936f0073549AD8b1fA53583600d629Ba9375161 ) => ( 824418490604617632277 )
                              • AdminUpgradeabilityProxy.70a08231( )
                                • RenderToken.balanceOf( _owner=0xe66B31678d6C16E9ebf358268a790B763C133750 ) => ( 401272611412376962441 )
                                • AdminUpgradeabilityProxy.70a08231( )
                                  • RenderToken.balanceOf( _owner=0xe66B31678d6C16E9ebf358268a790B763C133750 ) => ( 401272611412376962441 )
                                  • AdminUpgradeabilityProxy.a9059cbb( )
                                    • RenderToken.transfer( _to=0x4814E8Edcb3634295A6AeE285Aa05e8F1BDF3942, _value=401272611412376962441 ) => ( True )
                                      File 1 of 11: ZeroExProxy
                                      // SPDX-License-Identifier: GPL-3.0
                                      pragma solidity 0.6.12;
                                      interface IZeroEx {
                                          function getFunctionImplementation(bytes4 _signature) external returns (address);
                                      }// SPDX-License-Identifier: GPL-3.0
                                      pragma solidity 0.6.12;
                                      pragma experimental ABIEncoderV2;
                                      import "./IZeroEx.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
                                      import "@0x/contracts-zero-ex/contracts/src/errors/LibProxyRichErrors.sol";
                                      import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                                      import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                                      import "@openzeppelin/contracts/access/Ownable.sol";
                                      /// @title Coinbase proxy contract for 0x proxy
                                      /// @dev A generic proxy contract which extracts a fee before delegation
                                      contract ZeroExProxy is Ownable {
                                          using LibBytesV06 for bytes;
                                          using SafeERC20 for IERC20;
                                          using SafeMath for uint256;
                                          address private constant _ETH_ADDRESS = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
                                          address private constant _NULL_ADDRESS = 0x0000000000000000000000000000000000000000;
                                          address payable private _beneficiary;
                                          address payable private _allowanceTarget;
                                          IZeroEx private _zeroEx;
                                          mapping(bytes4 => address) private _implementationOverrides;
                                          event BeneficiaryChanged(address indexed beneficiary);
                                          event ImplementationOverrideSet(bytes4 indexed signature, address indexed implementation);
                                          event AllowanceTargetChanged(address indexed allowanceTarget);
                                          event ZeroExChanged(address indexed zeroEx);
                                          /// @dev Construct this contract and specify a fee beneficiary, 0x proxy contract address, and allowance target
                                          constructor(
                                              IZeroEx zeroEx, 
                                              address payable allowanceTarget, 
                                              address payable beneficiary
                                          ) public {
                                              _zeroEx = zeroEx;
                                              _allowanceTarget = allowanceTarget;
                                              _beneficiary = beneficiary;
                                          }
                                          /// @dev Fallback for just receiving ether.
                                          receive() external payable {}
                                          /// @dev Delegates calls to the specified implementation contract and extracts a fee based on provided arguments
                                          /// @param msgData The byte data representing a swap using the original ZeroEx contract. This is either recieved from the 0x API directly or we construct it in order to perform a Uniswap trade
                                          /// @param feeToken The ERC20 we wish to extract a user fee from. If this is ETH it should be the standard 0xeee ETH address
                                          /// @param fee Fee amount collected and sent to the beneficiary
                                          function optimalSwap(
                                              bytes calldata msgData, 
                                              address feeToken, 
                                              uint256 fee
                                          ) external payable returns (bytes memory) {
                                              _payFees(feeToken, fee);
                                              bytes4 signature = msgData.readBytes4(0);
                                              address target = getFunctionImplementation(signature);
                                              if (target == address(0)) {
                                                  _revertWithData(LibProxyRichErrors.NotImplementedError(signature));
                                              }
                                              (bool success, bytes memory resultData) = target.delegatecall(msgData);
                                              if (!success) {
                                                  _revertWithData(resultData);
                                              }
                                              _returnWithData(resultData);
                                          }
                                          /// @dev Forwards calls to the zeroEx contract and extracts a fee based on provided arguments
                                          /// @param msgData The byte data representing a swap using the original ZeroEx contract. This is either recieved from the 0x API directly or we construct it in order to perform a Uniswap trade
                                          /// @param feeToken The ERC20 we wish to extract a user fee from. If this is ETH it should be the standard 0xeee ETH address
                                          /// @param inputToken The ERC20 the user is selling. If this is ETH it should be the standard 0xeee ETH address
                                          /// @param inputAmount The amount of _inputToken being sold
                                          /// @param outputToken The ERC20 the user is buying. If this is ETH it should be the standard 0xeee ETH address
                                          /// @param fee Fee amount collected and sent to the beneficiary
                                          function proxiedSwap(
                                              bytes calldata msgData, 
                                              address feeToken, 
                                              address inputToken, 
                                              uint256 inputAmount, 
                                              address outputToken, 
                                              uint256 fee
                                          ) external payable returns (bytes memory) {
                                              _payFees(feeToken, fee);
                                              uint256 value = 0;
                                              if (inputToken == _ETH_ADDRESS) {
                                                  if (feeToken == _ETH_ADDRESS) {
                                                      require(msg.value == inputAmount.add(fee),"Insufficient value with fee");
                                                  }
                                                  else {
                                                      require(msg.value == inputAmount, "Insufficient value");
                                                  }
                                                  value = inputAmount;
                                              }
                                              else {
                                                  _sendERC20(IERC20(inputToken), msg.sender, address(this), inputAmount);
                                                  uint256 allowedAmount = IERC20(inputToken).allowance(address(this), _allowanceTarget);
                                                  if (allowedAmount < inputAmount) {
                                                      IERC20(inputToken).safeIncreaseAllowance(_allowanceTarget, inputAmount.sub(allowedAmount));
                                                  }
                                              }
                                              (bool success, bytes memory resultData) = address(_zeroEx).call{value: value}(msgData);
                                              if (!success) {
                                                  _revertWithData(resultData);
                                              }
                                              if (outputToken == _ETH_ADDRESS) {
                                                  if (address(this).balance > 0) {
                                                      _sendETH(msg.sender, address(this).balance);
                                                  } else {
                                                      _revertWithData(resultData);
                                                  }
                                              } else {
                                                  uint256 tokenBalance = IERC20(outputToken).balanceOf(address(this));
                                                  if (tokenBalance > 0) {
                                                      IERC20(outputToken).safeTransfer(msg.sender, tokenBalance);
                                                  } else {
                                                      _revertWithData(resultData);
                                                  }
                                              }
                                              _returnWithData(resultData);
                                          }
                                          /// @dev Set a new 0x proxy contract address
                                          /// @param newZeroEx New 0x proxy address
                                          function setZeroEx(IZeroEx newZeroEx) public onlyOwner{
                                              require(address(newZeroEx) != _NULL_ADDRESS, "Invalid zeroEx address");
                                              _zeroEx = newZeroEx;
                                              emit ZeroExChanged(address(_zeroEx));
                                          }
                                          /// @dev Set a new new allowance target address 
                                          /// @param newAllowanceTarget New allowance target address
                                          function setAllowanceTarget(address payable newAllowanceTarget) public onlyOwner {
                                              require(newAllowanceTarget != _NULL_ADDRESS, "Invalid allowance target");
                                              _allowanceTarget = newAllowanceTarget;
                                              emit AllowanceTargetChanged(_allowanceTarget);
                                          }
                                          /// @dev Set a new beneficiary address 
                                          /// @param beneficiary New beneficiary target address
                                          function setBeneficiary(address payable beneficiary) public onlyOwner {
                                              require(beneficiary != _NULL_ADDRESS, "Invalid beneficiary");
                                              _beneficiary = beneficiary;
                                              emit BeneficiaryChanged(_beneficiary);
                                          }
                                          /// @dev Set a custom implementation feature  
                                          /// @param signature function signature
                                          /// @param implementation address of the custom feature
                                          function setImplementationOverride(bytes4 signature, address implementation) public onlyOwner {
                                              _implementationOverrides[signature] = implementation;
                                              emit ImplementationOverrideSet(signature, implementation);
                                          }
                                          /// @dev Get function implementation address based on signature 
                                          /// @param signature function signature
                                          /// @return impl address of implementation
                                          function getFunctionImplementation(bytes4 signature) public returns (address impl) {
                                              impl = _implementationOverrides[signature];
                                              if (impl == _NULL_ADDRESS) {
                                                  impl = _zeroEx.getFunctionImplementation(signature);
                                              }
                                          }
                                          function getBeneficiary() public view returns(address) {
                                              return _beneficiary;
                                          }
                                          function getAllowanceTarget() public view returns(address){
                                              return _allowanceTarget;
                                          }
                                          function getZeroEx() public view returns(IZeroEx) {
                                              return _zeroEx;
                                          }
                                          /// @dev Pay fee to beneficiary 
                                          /// @param token token address to pay fee in, can be ETH
                                          /// @param amount fee amount to pay
                                          function _payFees(address token, uint256 amount) private {
                                              if (token == _ETH_ADDRESS) {
                                                  return _sendETH(_beneficiary, amount);
                                              }
                                              return _sendERC20(IERC20(token), msg.sender, _beneficiary, amount);
                                          }
                                          function _sendETH(address payable toAddress, uint256 amount) private {
                                              if (amount > 0) {
                                                  (bool success,) = toAddress.call{ value: amount }("");
                                                  require(success, "Unable to send ETH");
                                              }
                                          }
                                          function _sendERC20(IERC20 token, address fromAddress, address toAddress, uint256 amount) private {
                                              if (amount > 0) {
                                                  token.safeTransferFrom(fromAddress, toAddress, amount);
                                              }
                                          }
                                          /// @dev Revert with arbitrary bytes.
                                          /// @param data Revert data.
                                          function _revertWithData(bytes memory data) private pure {
                                              assembly { revert(add(data, 32), mload(data)) }
                                          }
                                          /// @dev Return with arbitrary bytes.
                                          /// @param data Return data.
                                          function _returnWithData(bytes memory data) private pure {
                                              assembly { return(add(data, 32), mload(data)) }
                                          }
                                      }// SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./errors/LibBytesRichErrorsV06.sol";
                                      import "./errors/LibRichErrorsV06.sol";
                                      library LibBytesV06 {
                                          using LibBytesV06 for bytes;
                                          /// @dev Gets the memory address for a byte array.
                                          /// @param input Byte array to lookup.
                                          /// @return memoryAddress Memory address of byte array. This
                                          ///         points to the header of the byte array which contains
                                          ///         the length.
                                          function rawAddress(bytes memory input)
                                              internal
                                              pure
                                              returns (uint256 memoryAddress)
                                          {
                                              assembly {
                                                  memoryAddress := input
                                              }
                                              return memoryAddress;
                                          }
                                          /// @dev Gets the memory address for the contents of a byte array.
                                          /// @param input Byte array to lookup.
                                          /// @return memoryAddress Memory address of the contents of the byte array.
                                          function contentAddress(bytes memory input)
                                              internal
                                              pure
                                              returns (uint256 memoryAddress)
                                          {
                                              assembly {
                                                  memoryAddress := add(input, 32)
                                              }
                                              return memoryAddress;
                                          }
                                          /// @dev Copies `length` bytes from memory location `source` to `dest`.
                                          /// @param dest memory address to copy bytes to.
                                          /// @param source memory address to copy bytes from.
                                          /// @param length number of bytes to copy.
                                          function memCopy(
                                              uint256 dest,
                                              uint256 source,
                                              uint256 length
                                          )
                                              internal
                                              pure
                                          {
                                              if (length < 32) {
                                                  // Handle a partial word by reading destination and masking
                                                  // off the bits we are interested in.
                                                  // This correctly handles overlap, zero lengths and source == dest
                                                  assembly {
                                                      let mask := sub(exp(256, sub(32, length)), 1)
                                                      let s := and(mload(source), not(mask))
                                                      let d := and(mload(dest), mask)
                                                      mstore(dest, or(s, d))
                                                  }
                                              } else {
                                                  // Skip the O(length) loop when source == dest.
                                                  if (source == dest) {
                                                      return;
                                                  }
                                                  // For large copies we copy whole words at a time. The final
                                                  // word is aligned to the end of the range (instead of after the
                                                  // previous) to handle partial words. So a copy will look like this:
                                                  //
                                                  //  ####
                                                  //      ####
                                                  //          ####
                                                  //            ####
                                                  //
                                                  // We handle overlap in the source and destination range by
                                                  // changing the copying direction. This prevents us from
                                                  // overwriting parts of source that we still need to copy.
                                                  //
                                                  // This correctly handles source == dest
                                                  //
                                                  if (source > dest) {
                                                      assembly {
                                                          // We subtract 32 from `sEnd` and `dEnd` because it
                                                          // is easier to compare with in the loop, and these
                                                          // are also the addresses we need for copying the
                                                          // last bytes.
                                                          length := sub(length, 32)
                                                          let sEnd := add(source, length)
                                                          let dEnd := add(dest, length)
                                                          // Remember the last 32 bytes of source
                                                          // This needs to be done here and not after the loop
                                                          // because we may have overwritten the last bytes in
                                                          // source already due to overlap.
                                                          let last := mload(sEnd)
                                                          // Copy whole words front to back
                                                          // Note: the first check is always true,
                                                          // this could have been a do-while loop.
                                                          // solhint-disable-next-line no-empty-blocks
                                                          for {} lt(source, sEnd) {} {
                                                              mstore(dest, mload(source))
                                                              source := add(source, 32)
                                                              dest := add(dest, 32)
                                                          }
                                                          // Write the last 32 bytes
                                                          mstore(dEnd, last)
                                                      }
                                                  } else {
                                                      assembly {
                                                          // We subtract 32 from `sEnd` and `dEnd` because those
                                                          // are the starting points when copying a word at the end.
                                                          length := sub(length, 32)
                                                          let sEnd := add(source, length)
                                                          let dEnd := add(dest, length)
                                                          // Remember the first 32 bytes of source
                                                          // This needs to be done here and not after the loop
                                                          // because we may have overwritten the first bytes in
                                                          // source already due to overlap.
                                                          let first := mload(source)
                                                          // Copy whole words back to front
                                                          // We use a signed comparisson here to allow dEnd to become
                                                          // negative (happens when source and dest < 32). Valid
                                                          // addresses in local memory will never be larger than
                                                          // 2**255, so they can be safely re-interpreted as signed.
                                                          // Note: the first check is always true,
                                                          // this could have been a do-while loop.
                                                          // solhint-disable-next-line no-empty-blocks
                                                          for {} slt(dest, dEnd) {} {
                                                              mstore(dEnd, mload(sEnd))
                                                              sEnd := sub(sEnd, 32)
                                                              dEnd := sub(dEnd, 32)
                                                          }
                                                          // Write the first 32 bytes
                                                          mstore(dest, first)
                                                      }
                                                  }
                                              }
                                          }
                                          /// @dev Returns a slices from a byte array.
                                          /// @param b The byte array to take a slice from.
                                          /// @param from The starting index for the slice (inclusive).
                                          /// @param to The final index for the slice (exclusive).
                                          /// @return result The slice containing bytes at indices [from, to)
                                          function slice(
                                              bytes memory b,
                                              uint256 from,
                                              uint256 to
                                          )
                                              internal
                                              pure
                                              returns (bytes memory result)
                                          {
                                              // Ensure that the from and to positions are valid positions for a slice within
                                              // the byte array that is being used.
                                              if (from > to) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.FromLessThanOrEqualsToRequired,
                                                      from,
                                                      to
                                                  ));
                                              }
                                              if (to > b.length) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.ToLessThanOrEqualsLengthRequired,
                                                      to,
                                                      b.length
                                                  ));
                                              }
                                              // Create a new bytes structure and copy contents
                                              result = new bytes(to - from);
                                              memCopy(
                                                  result.contentAddress(),
                                                  b.contentAddress() + from,
                                                  result.length
                                              );
                                              return result;
                                          }
                                          /// @dev Returns a slice from a byte array without preserving the input.
                                          ///      When `from == 0`, the original array will match the slice.
                                          ///      In other cases its state will be corrupted.
                                          /// @param b The byte array to take a slice from. Will be destroyed in the process.
                                          /// @param from The starting index for the slice (inclusive).
                                          /// @param to The final index for the slice (exclusive).
                                          /// @return result The slice containing bytes at indices [from, to)
                                          function sliceDestructive(
                                              bytes memory b,
                                              uint256 from,
                                              uint256 to
                                          )
                                              internal
                                              pure
                                              returns (bytes memory result)
                                          {
                                              // Ensure that the from and to positions are valid positions for a slice within
                                              // the byte array that is being used.
                                              if (from > to) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.FromLessThanOrEqualsToRequired,
                                                      from,
                                                      to
                                                  ));
                                              }
                                              if (to > b.length) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.ToLessThanOrEqualsLengthRequired,
                                                      to,
                                                      b.length
                                                  ));
                                              }
                                              // Create a new bytes structure around [from, to) in-place.
                                              assembly {
                                                  result := add(b, from)
                                                  mstore(result, sub(to, from))
                                              }
                                              return result;
                                          }
                                          /// @dev Pops the last byte off of a byte array by modifying its length.
                                          /// @param b Byte array that will be modified.
                                          /// @return result The byte that was popped off.
                                          function popLastByte(bytes memory b)
                                              internal
                                              pure
                                              returns (bytes1 result)
                                          {
                                              if (b.length == 0) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanZeroRequired,
                                                      b.length,
                                                      0
                                                  ));
                                              }
                                              // Store last byte.
                                              result = b[b.length - 1];
                                              assembly {
                                                  // Decrement length of byte array.
                                                  let newLen := sub(mload(b), 1)
                                                  mstore(b, newLen)
                                              }
                                              return result;
                                          }
                                          /// @dev Tests equality of two byte arrays.
                                          /// @param lhs First byte array to compare.
                                          /// @param rhs Second byte array to compare.
                                          /// @return equal True if arrays are the same. False otherwise.
                                          function equals(
                                              bytes memory lhs,
                                              bytes memory rhs
                                          )
                                              internal
                                              pure
                                              returns (bool equal)
                                          {
                                              // Keccak gas cost is 30 + numWords * 6. This is a cheap way to compare.
                                              // We early exit on unequal lengths, but keccak would also correctly
                                              // handle this.
                                              return lhs.length == rhs.length && keccak256(lhs) == keccak256(rhs);
                                          }
                                          /// @dev Reads an address from a position in a byte array.
                                          /// @param b Byte array containing an address.
                                          /// @param index Index in byte array of address.
                                          /// @return result address from byte array.
                                          function readAddress(
                                              bytes memory b,
                                              uint256 index
                                          )
                                              internal
                                              pure
                                              returns (address result)
                                          {
                                              if (b.length < index + 20) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsTwentyRequired,
                                                      b.length,
                                                      index + 20 // 20 is length of address
                                                  ));
                                              }
                                              // Add offset to index:
                                              // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
                                              // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
                                              index += 20;
                                              // Read address from array memory
                                              assembly {
                                                  // 1. Add index to address of bytes array
                                                  // 2. Load 32-byte word from memory
                                                  // 3. Apply 20-byte mask to obtain address
                                                  result := and(mload(add(b, index)), 0xffffffffffffffffffffffffffffffffffffffff)
                                              }
                                              return result;
                                          }
                                          /// @dev Writes an address into a specific position in a byte array.
                                          /// @param b Byte array to insert address into.
                                          /// @param index Index in byte array of address.
                                          /// @param input Address to put into byte array.
                                          function writeAddress(
                                              bytes memory b,
                                              uint256 index,
                                              address input
                                          )
                                              internal
                                              pure
                                          {
                                              if (b.length < index + 20) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsTwentyRequired,
                                                      b.length,
                                                      index + 20 // 20 is length of address
                                                  ));
                                              }
                                              // Add offset to index:
                                              // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
                                              // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
                                              index += 20;
                                              // Store address into array memory
                                              assembly {
                                                  // The address occupies 20 bytes and mstore stores 32 bytes.
                                                  // First fetch the 32-byte word where we'll be storing the address, then
                                                  // apply a mask so we have only the bytes in the word that the address will not occupy.
                                                  // Then combine these bytes with the address and store the 32 bytes back to memory with mstore.
                                                  // 1. Add index to address of bytes array
                                                  // 2. Load 32-byte word from memory
                                                  // 3. Apply 12-byte mask to obtain extra bytes occupying word of memory where we'll store the address
                                                  let neighbors := and(
                                                      mload(add(b, index)),
                                                      0xffffffffffffffffffffffff0000000000000000000000000000000000000000
                                                  )
                                                  // Make sure input address is clean.
                                                  // (Solidity does not guarantee this)
                                                  input := and(input, 0xffffffffffffffffffffffffffffffffffffffff)
                                                  // Store the neighbors and address into memory
                                                  mstore(add(b, index), xor(input, neighbors))
                                              }
                                          }
                                          /// @dev Reads a bytes32 value from a position in a byte array.
                                          /// @param b Byte array containing a bytes32 value.
                                          /// @param index Index in byte array of bytes32 value.
                                          /// @return result bytes32 value from byte array.
                                          function readBytes32(
                                              bytes memory b,
                                              uint256 index
                                          )
                                              internal
                                              pure
                                              returns (bytes32 result)
                                          {
                                              if (b.length < index + 32) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsThirtyTwoRequired,
                                                      b.length,
                                                      index + 32
                                                  ));
                                              }
                                              // Arrays are prefixed by a 256 bit length parameter
                                              index += 32;
                                              // Read the bytes32 from array memory
                                              assembly {
                                                  result := mload(add(b, index))
                                              }
                                              return result;
                                          }
                                          /// @dev Writes a bytes32 into a specific position in a byte array.
                                          /// @param b Byte array to insert <input> into.
                                          /// @param index Index in byte array of <input>.
                                          /// @param input bytes32 to put into byte array.
                                          function writeBytes32(
                                              bytes memory b,
                                              uint256 index,
                                              bytes32 input
                                          )
                                              internal
                                              pure
                                          {
                                              if (b.length < index + 32) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsThirtyTwoRequired,
                                                      b.length,
                                                      index + 32
                                                  ));
                                              }
                                              // Arrays are prefixed by a 256 bit length parameter
                                              index += 32;
                                              // Read the bytes32 from array memory
                                              assembly {
                                                  mstore(add(b, index), input)
                                              }
                                          }
                                          /// @dev Reads a uint256 value from a position in a byte array.
                                          /// @param b Byte array containing a uint256 value.
                                          /// @param index Index in byte array of uint256 value.
                                          /// @return result uint256 value from byte array.
                                          function readUint256(
                                              bytes memory b,
                                              uint256 index
                                          )
                                              internal
                                              pure
                                              returns (uint256 result)
                                          {
                                              result = uint256(readBytes32(b, index));
                                              return result;
                                          }
                                          /// @dev Writes a uint256 into a specific position in a byte array.
                                          /// @param b Byte array to insert <input> into.
                                          /// @param index Index in byte array of <input>.
                                          /// @param input uint256 to put into byte array.
                                          function writeUint256(
                                              bytes memory b,
                                              uint256 index,
                                              uint256 input
                                          )
                                              internal
                                              pure
                                          {
                                              writeBytes32(b, index, bytes32(input));
                                          }
                                          /// @dev Reads an unpadded bytes4 value from a position in a byte array.
                                          /// @param b Byte array containing a bytes4 value.
                                          /// @param index Index in byte array of bytes4 value.
                                          /// @return result bytes4 value from byte array.
                                          function readBytes4(
                                              bytes memory b,
                                              uint256 index
                                          )
                                              internal
                                              pure
                                              returns (bytes4 result)
                                          {
                                              if (b.length < index + 4) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsFourRequired,
                                                      b.length,
                                                      index + 4
                                                  ));
                                              }
                                              // Arrays are prefixed by a 32 byte length field
                                              index += 32;
                                              // Read the bytes4 from array memory
                                              assembly {
                                                  result := mload(add(b, index))
                                                  // Solidity does not require us to clean the trailing bytes.
                                                  // We do it anyway
                                                  result := and(result, 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000)
                                              }
                                              return result;
                                          }
                                          /// @dev Writes a new length to a byte array.
                                          ///      Decreasing length will lead to removing the corresponding lower order bytes from the byte array.
                                          ///      Increasing length may lead to appending adjacent in-memory bytes to the end of the byte array.
                                          /// @param b Bytes array to write new length to.
                                          /// @param length New length of byte array.
                                          function writeLength(bytes memory b, uint256 length)
                                              internal
                                              pure
                                          {
                                              assembly {
                                                  mstore(b, length)
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibBytesRichErrorsV06 {
                                          enum InvalidByteOperationErrorCodes {
                                              FromLessThanOrEqualsToRequired,
                                              ToLessThanOrEqualsLengthRequired,
                                              LengthGreaterThanZeroRequired,
                                              LengthGreaterThanOrEqualsFourRequired,
                                              LengthGreaterThanOrEqualsTwentyRequired,
                                              LengthGreaterThanOrEqualsThirtyTwoRequired,
                                              LengthGreaterThanOrEqualsNestedBytesLengthRequired,
                                              DestinationLengthGreaterThanOrEqualSourceLengthRequired
                                          }
                                          // bytes4(keccak256("InvalidByteOperationError(uint8,uint256,uint256)"))
                                          bytes4 internal constant INVALID_BYTE_OPERATION_ERROR_SELECTOR =
                                              0x28006595;
                                          // solhint-disable func-name-mixedcase
                                          function InvalidByteOperationError(
                                              InvalidByteOperationErrorCodes errorCode,
                                              uint256 offset,
                                              uint256 required
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  INVALID_BYTE_OPERATION_ERROR_SELECTOR,
                                                  errorCode,
                                                  offset,
                                                  required
                                              );
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibRichErrorsV06 {
                                          // bytes4(keccak256("Error(string)"))
                                          bytes4 internal constant STANDARD_ERROR_SELECTOR = 0x08c379a0;
                                          // solhint-disable func-name-mixedcase
                                          /// @dev ABI encode a standard, string revert error payload.
                                          ///      This is the same payload that would be included by a `revert(string)`
                                          ///      solidity statement. It has the function signature `Error(string)`.
                                          /// @param message The error string.
                                          /// @return The ABI encoded error.
                                          function StandardError(string memory message)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  STANDARD_ERROR_SELECTOR,
                                                  bytes(message)
                                              );
                                          }
                                          // solhint-enable func-name-mixedcase
                                          /// @dev Reverts an encoded rich revert reason `errorData`.
                                          /// @param errorData ABI encoded error data.
                                          function rrevert(bytes memory errorData)
                                              internal
                                              pure
                                          {
                                              assembly {
                                                  revert(add(errorData, 0x20), mload(errorData))
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibProxyRichErrors {
                                          // solhint-disable func-name-mixedcase
                                          function NotImplementedError(bytes4 selector)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("NotImplementedError(bytes4)")),
                                                  selector
                                              );
                                          }
                                          function InvalidBootstrapCallerError(address actual, address expected)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InvalidBootstrapCallerError(address,address)")),
                                                  actual,
                                                  expected
                                              );
                                          }
                                          function InvalidDieCallerError(address actual, address expected)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InvalidDieCallerError(address,address)")),
                                                  actual,
                                                  expected
                                              );
                                          }
                                          function BootstrapCallFailedError(address target, bytes memory resultData)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("BootstrapCallFailedError(address,bytes)")),
                                                  target,
                                                  resultData
                                              );
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity >=0.6.0 <0.8.0;
                                      import "../utils/Context.sol";
                                      /**
                                       * @dev Contract module which provides a basic access control mechanism, where
                                       * there is an account (an owner) that can be granted exclusive access to
                                       * specific functions.
                                       *
                                       * By default, the owner account will be the one that deploys the contract. This
                                       * can later be changed with {transferOwnership}.
                                       *
                                       * This module is used through inheritance. It will make available the modifier
                                       * `onlyOwner`, which can be applied to your functions to restrict their use to
                                       * the owner.
                                       */
                                      abstract contract Ownable is Context {
                                          address private _owner;
                                          event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
                                          /**
                                           * @dev Initializes the contract setting the deployer as the initial owner.
                                           */
                                          constructor () internal {
                                              address msgSender = _msgSender();
                                              _owner = msgSender;
                                              emit OwnershipTransferred(address(0), msgSender);
                                          }
                                          /**
                                           * @dev Returns the address of the current owner.
                                           */
                                          function owner() public view virtual returns (address) {
                                              return _owner;
                                          }
                                          /**
                                           * @dev Throws if called by any account other than the owner.
                                           */
                                          modifier onlyOwner() {
                                              require(owner() == _msgSender(), "Ownable: caller is not the owner");
                                              _;
                                          }
                                          /**
                                           * @dev Leaves the contract without owner. It will not be possible to call
                                           * `onlyOwner` functions anymore. Can only be called by the current owner.
                                           *
                                           * NOTE: Renouncing ownership will leave the contract without an owner,
                                           * thereby removing any functionality that is only available to the owner.
                                           */
                                          function renounceOwnership() public virtual onlyOwner {
                                              emit OwnershipTransferred(_owner, address(0));
                                              _owner = address(0);
                                          }
                                          /**
                                           * @dev Transfers ownership of the contract to a new account (`newOwner`).
                                           * Can only be called by the current owner.
                                           */
                                          function transferOwnership(address newOwner) public virtual onlyOwner {
                                              require(newOwner != address(0), "Ownable: new owner is the zero address");
                                              emit OwnershipTransferred(_owner, newOwner);
                                              _owner = newOwner;
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity >=0.6.0 <0.8.0;
                                      /**
                                       * @dev Wrappers over Solidity's arithmetic operations with added overflow
                                       * checks.
                                       *
                                       * Arithmetic operations in Solidity wrap on overflow. This can easily result
                                       * in bugs, because programmers usually assume that an overflow raises an
                                       * error, which is the standard behavior in high level programming languages.
                                       * `SafeMath` restores this intuition by reverting the transaction when an
                                       * operation overflows.
                                       *
                                       * Using this library instead of the unchecked operations eliminates an entire
                                       * class of bugs, so it's recommended to use it always.
                                       */
                                      library SafeMath {
                                          /**
                                           * @dev Returns the addition of two unsigned integers, with an overflow flag.
                                           *
                                           * _Available since v3.4._
                                           */
                                          function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                                              uint256 c = a + b;
                                              if (c < a) return (false, 0);
                                              return (true, c);
                                          }
                                          /**
                                           * @dev Returns the substraction of two unsigned integers, with an overflow flag.
                                           *
                                           * _Available since v3.4._
                                           */
                                          function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                                              if (b > a) return (false, 0);
                                              return (true, a - b);
                                          }
                                          /**
                                           * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
                                           *
                                           * _Available since v3.4._
                                           */
                                          function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                                              // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
                                              // benefit is lost if 'b' is also tested.
                                              // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
                                              if (a == 0) return (true, 0);
                                              uint256 c = a * b;
                                              if (c / a != b) return (false, 0);
                                              return (true, c);
                                          }
                                          /**
                                           * @dev Returns the division of two unsigned integers, with a division by zero flag.
                                           *
                                           * _Available since v3.4._
                                           */
                                          function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                                              if (b == 0) return (false, 0);
                                              return (true, a / b);
                                          }
                                          /**
                                           * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
                                           *
                                           * _Available since v3.4._
                                           */
                                          function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
                                              if (b == 0) return (false, 0);
                                              return (true, a % b);
                                          }
                                          /**
                                           * @dev Returns the addition of two unsigned integers, reverting on
                                           * overflow.
                                           *
                                           * Counterpart to Solidity's `+` operator.
                                           *
                                           * Requirements:
                                           *
                                           * - Addition cannot overflow.
                                           */
                                          function add(uint256 a, uint256 b) internal pure returns (uint256) {
                                              uint256 c = a + b;
                                              require(c >= a, "SafeMath: addition overflow");
                                              return c;
                                          }
                                          /**
                                           * @dev Returns the subtraction of two unsigned integers, reverting on
                                           * overflow (when the result is negative).
                                           *
                                           * Counterpart to Solidity's `-` operator.
                                           *
                                           * Requirements:
                                           *
                                           * - Subtraction cannot overflow.
                                           */
                                          function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                                              require(b <= a, "SafeMath: subtraction overflow");
                                              return a - b;
                                          }
                                          /**
                                           * @dev Returns the multiplication of two unsigned integers, reverting on
                                           * overflow.
                                           *
                                           * Counterpart to Solidity's `*` operator.
                                           *
                                           * Requirements:
                                           *
                                           * - Multiplication cannot overflow.
                                           */
                                          function mul(uint256 a, uint256 b) internal pure returns (uint256) {
                                              if (a == 0) return 0;
                                              uint256 c = a * b;
                                              require(c / a == b, "SafeMath: multiplication overflow");
                                              return c;
                                          }
                                          /**
                                           * @dev Returns the integer division of two unsigned integers, reverting on
                                           * division by zero. The result is rounded towards zero.
                                           *
                                           * Counterpart to Solidity's `/` operator. Note: this function uses a
                                           * `revert` opcode (which leaves remaining gas untouched) while Solidity
                                           * uses an invalid opcode to revert (consuming all remaining gas).
                                           *
                                           * Requirements:
                                           *
                                           * - The divisor cannot be zero.
                                           */
                                          function div(uint256 a, uint256 b) internal pure returns (uint256) {
                                              require(b > 0, "SafeMath: division by zero");
                                              return a / b;
                                          }
                                          /**
                                           * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                                           * reverting when dividing by zero.
                                           *
                                           * Counterpart to Solidity's `%` operator. This function uses a `revert`
                                           * opcode (which leaves remaining gas untouched) while Solidity uses an
                                           * invalid opcode to revert (consuming all remaining gas).
                                           *
                                           * Requirements:
                                           *
                                           * - The divisor cannot be zero.
                                           */
                                          function mod(uint256 a, uint256 b) internal pure returns (uint256) {
                                              require(b > 0, "SafeMath: modulo by zero");
                                              return a % b;
                                          }
                                          /**
                                           * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                                           * overflow (when the result is negative).
                                           *
                                           * CAUTION: This function is deprecated because it requires allocating memory for the error
                                           * message unnecessarily. For custom revert reasons use {trySub}.
                                           *
                                           * Counterpart to Solidity's `-` operator.
                                           *
                                           * Requirements:
                                           *
                                           * - Subtraction cannot overflow.
                                           */
                                          function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                                              require(b <= a, errorMessage);
                                              return a - b;
                                          }
                                          /**
                                           * @dev Returns the integer division of two unsigned integers, reverting with custom message on
                                           * division by zero. The result is rounded towards zero.
                                           *
                                           * CAUTION: This function is deprecated because it requires allocating memory for the error
                                           * message unnecessarily. For custom revert reasons use {tryDiv}.
                                           *
                                           * Counterpart to Solidity's `/` operator. Note: this function uses a
                                           * `revert` opcode (which leaves remaining gas untouched) while Solidity
                                           * uses an invalid opcode to revert (consuming all remaining gas).
                                           *
                                           * Requirements:
                                           *
                                           * - The divisor cannot be zero.
                                           */
                                          function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                                              require(b > 0, errorMessage);
                                              return a / b;
                                          }
                                          /**
                                           * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                                           * reverting with custom message when dividing by zero.
                                           *
                                           * CAUTION: This function is deprecated because it requires allocating memory for the error
                                           * message unnecessarily. For custom revert reasons use {tryMod}.
                                           *
                                           * Counterpart to Solidity's `%` operator. This function uses a `revert`
                                           * opcode (which leaves remaining gas untouched) while Solidity uses an
                                           * invalid opcode to revert (consuming all remaining gas).
                                           *
                                           * Requirements:
                                           *
                                           * - The divisor cannot be zero.
                                           */
                                          function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
                                              require(b > 0, errorMessage);
                                              return a % b;
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity >=0.6.0 <0.8.0;
                                      /**
                                       * @dev Interface of the ERC20 standard as defined in the EIP.
                                       */
                                      interface IERC20 {
                                          /**
                                           * @dev Returns the amount of tokens in existence.
                                           */
                                          function totalSupply() external view returns (uint256);
                                          /**
                                           * @dev Returns the amount of tokens owned by `account`.
                                           */
                                          function balanceOf(address account) external view returns (uint256);
                                          /**
                                           * @dev Moves `amount` tokens from the caller's account to `recipient`.
                                           *
                                           * Returns a boolean value indicating whether the operation succeeded.
                                           *
                                           * Emits a {Transfer} event.
                                           */
                                          function transfer(address recipient, uint256 amount) external returns (bool);
                                          /**
                                           * @dev Returns the remaining number of tokens that `spender` will be
                                           * allowed to spend on behalf of `owner` through {transferFrom}. This is
                                           * zero by default.
                                           *
                                           * This value changes when {approve} or {transferFrom} are called.
                                           */
                                          function allowance(address owner, address spender) external view returns (uint256);
                                          /**
                                           * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
                                           *
                                           * Returns a boolean value indicating whether the operation succeeded.
                                           *
                                           * IMPORTANT: Beware that changing an allowance with this method brings the risk
                                           * that someone may use both the old and the new allowance by unfortunate
                                           * transaction ordering. One possible solution to mitigate this race
                                           * condition is to first reduce the spender's allowance to 0 and set the
                                           * desired value afterwards:
                                           * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                                           *
                                           * Emits an {Approval} event.
                                           */
                                          function approve(address spender, uint256 amount) external returns (bool);
                                          /**
                                           * @dev Moves `amount` tokens from `sender` to `recipient` using the
                                           * allowance mechanism. `amount` is then deducted from the caller's
                                           * allowance.
                                           *
                                           * Returns a boolean value indicating whether the operation succeeded.
                                           *
                                           * Emits a {Transfer} event.
                                           */
                                          function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
                                          /**
                                           * @dev Emitted when `value` tokens are moved from one account (`from`) to
                                           * another (`to`).
                                           *
                                           * Note that `value` may be zero.
                                           */
                                          event Transfer(address indexed from, address indexed to, uint256 value);
                                          /**
                                           * @dev Emitted when the allowance of a `spender` for an `owner` is set by
                                           * a call to {approve}. `value` is the new allowance.
                                           */
                                          event Approval(address indexed owner, address indexed spender, uint256 value);
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity >=0.6.0 <0.8.0;
                                      import "./IERC20.sol";
                                      import "../../math/SafeMath.sol";
                                      import "../../utils/Address.sol";
                                      /**
                                       * @title SafeERC20
                                       * @dev Wrappers around ERC20 operations that throw on failure (when the token
                                       * contract returns false). Tokens that return no value (and instead revert or
                                       * throw on failure) are also supported, non-reverting calls are assumed to be
                                       * successful.
                                       * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
                                       * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
                                       */
                                      library SafeERC20 {
                                          using SafeMath for uint256;
                                          using Address for address;
                                          function safeTransfer(IERC20 token, address to, uint256 value) internal {
                                              _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
                                          }
                                          function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
                                              _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
                                          }
                                          /**
                                           * @dev Deprecated. This function has issues similar to the ones found in
                                           * {IERC20-approve}, and its usage is discouraged.
                                           *
                                           * Whenever possible, use {safeIncreaseAllowance} and
                                           * {safeDecreaseAllowance} instead.
                                           */
                                          function safeApprove(IERC20 token, address spender, uint256 value) internal {
                                              // safeApprove should only be called when setting an initial allowance,
                                              // or when resetting it to zero. To increase and decrease it, use
                                              // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
                                              // solhint-disable-next-line max-line-length
                                              require((value == 0) || (token.allowance(address(this), spender) == 0),
                                                  "SafeERC20: approve from non-zero to non-zero allowance"
                                              );
                                              _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
                                          }
                                          function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                                              uint256 newAllowance = token.allowance(address(this), spender).add(value);
                                              _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
                                          }
                                          function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                                              uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
                                              _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
                                          }
                                          /**
                                           * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
                                           * on the return value: the return value is optional (but if data is returned, it must not be false).
                                           * @param token The token targeted by the call.
                                           * @param data The call data (encoded using abi.encode or one of its variants).
                                           */
                                          function _callOptionalReturn(IERC20 token, bytes memory data) private {
                                              // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
                                              // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
                                              // the target address contains contract code and also asserts for success in the low-level call.
                                              bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
                                              if (returndata.length > 0) { // Return data is optional
                                                  // solhint-disable-next-line max-line-length
                                                  require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity >=0.6.2 <0.8.0;
                                      /**
                                       * @dev Collection of functions related to the address type
                                       */
                                      library Address {
                                          /**
                                           * @dev Returns true if `account` is a contract.
                                           *
                                           * [IMPORTANT]
                                           * ====
                                           * It is unsafe to assume that an address for which this function returns
                                           * false is an externally-owned account (EOA) and not a contract.
                                           *
                                           * Among others, `isContract` will return false for the following
                                           * types of addresses:
                                           *
                                           *  - an externally-owned account
                                           *  - a contract in construction
                                           *  - an address where a contract will be created
                                           *  - an address where a contract lived, but was destroyed
                                           * ====
                                           */
                                          function isContract(address account) internal view returns (bool) {
                                              // This method relies on extcodesize, which returns 0 for contracts in
                                              // construction, since the code is only stored at the end of the
                                              // constructor execution.
                                              uint256 size;
                                              // solhint-disable-next-line no-inline-assembly
                                              assembly { size := extcodesize(account) }
                                              return size > 0;
                                          }
                                          /**
                                           * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                                           * `recipient`, forwarding all available gas and reverting on errors.
                                           *
                                           * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                                           * of certain opcodes, possibly making contracts go over the 2300 gas limit
                                           * imposed by `transfer`, making them unable to receive funds via
                                           * `transfer`. {sendValue} removes this limitation.
                                           *
                                           * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                                           *
                                           * IMPORTANT: because control is transferred to `recipient`, care must be
                                           * taken to not create reentrancy vulnerabilities. Consider using
                                           * {ReentrancyGuard} or the
                                           * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                                           */
                                          function sendValue(address payable recipient, uint256 amount) internal {
                                              require(address(this).balance >= amount, "Address: insufficient balance");
                                              // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                                              (bool success, ) = recipient.call{ value: amount }("");
                                              require(success, "Address: unable to send value, recipient may have reverted");
                                          }
                                          /**
                                           * @dev Performs a Solidity function call using a low level `call`. A
                                           * plain`call` is an unsafe replacement for a function call: use this
                                           * function instead.
                                           *
                                           * If `target` reverts with a revert reason, it is bubbled up by this
                                           * function (like regular Solidity function calls).
                                           *
                                           * Returns the raw returned data. To convert to the expected return value,
                                           * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                                           *
                                           * Requirements:
                                           *
                                           * - `target` must be a contract.
                                           * - calling `target` with `data` must not revert.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                                            return functionCall(target, data, "Address: low-level call failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                                           * `errorMessage` as a fallback revert reason when `target` reverts.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                                              return functionCallWithValue(target, data, 0, errorMessage);
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                                           * but also transferring `value` wei to `target`.
                                           *
                                           * Requirements:
                                           *
                                           * - the calling contract must have an ETH balance of at least `value`.
                                           * - the called Solidity function must be `payable`.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                                              return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                                           * with `errorMessage` as a fallback revert reason when `target` reverts.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                                              require(address(this).balance >= value, "Address: insufficient balance for call");
                                              require(isContract(target), "Address: call to non-contract");
                                              // solhint-disable-next-line avoid-low-level-calls
                                              (bool success, bytes memory returndata) = target.call{ value: value }(data);
                                              return _verifyCallResult(success, returndata, errorMessage);
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                                           * but performing a static call.
                                           *
                                           * _Available since v3.3._
                                           */
                                          function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                                              return functionStaticCall(target, data, "Address: low-level static call failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                                           * but performing a static call.
                                           *
                                           * _Available since v3.3._
                                           */
                                          function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                                              require(isContract(target), "Address: static call to non-contract");
                                              // solhint-disable-next-line avoid-low-level-calls
                                              (bool success, bytes memory returndata) = target.staticcall(data);
                                              return _verifyCallResult(success, returndata, errorMessage);
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                                           * but performing a delegate call.
                                           *
                                           * _Available since v3.4._
                                           */
                                          function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
                                              return functionDelegateCall(target, data, "Address: low-level delegate call failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                                           * but performing a delegate call.
                                           *
                                           * _Available since v3.4._
                                           */
                                          function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                                              require(isContract(target), "Address: delegate call to non-contract");
                                              // solhint-disable-next-line avoid-low-level-calls
                                              (bool success, bytes memory returndata) = target.delegatecall(data);
                                              return _verifyCallResult(success, returndata, errorMessage);
                                          }
                                          function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                                              if (success) {
                                                  return returndata;
                                              } else {
                                                  // Look for revert reason and bubble it up if present
                                                  if (returndata.length > 0) {
                                                      // The easiest way to bubble the revert reason is using memory via assembly
                                                      // solhint-disable-next-line no-inline-assembly
                                                      assembly {
                                                          let returndata_size := mload(returndata)
                                                          revert(add(32, returndata), returndata_size)
                                                      }
                                                  } else {
                                                      revert(errorMessage);
                                                  }
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity >=0.6.0 <0.8.0;
                                      /*
                                       * @dev Provides information about the current execution context, including the
                                       * sender of the transaction and its data. While these are generally available
                                       * via msg.sender and msg.data, they should not be accessed in such a direct
                                       * manner, since when dealing with GSN meta-transactions the account sending and
                                       * paying for execution may not be the actual sender (as far as an application
                                       * is concerned).
                                       *
                                       * This contract is only required for intermediate, library-like contracts.
                                       */
                                      abstract contract Context {
                                          function _msgSender() internal view virtual returns (address payable) {
                                              return msg.sender;
                                          }
                                          function _msgData() internal view virtual returns (bytes memory) {
                                              this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
                                              return msg.data;
                                          }
                                      }
                                      

                                      File 2 of 11: AdminUpgradeabilityProxy
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.6.0;
                                      import './UpgradeabilityProxy.sol';
                                      /**
                                       * @title AdminUpgradeabilityProxy
                                       * @dev This contract combines an upgradeability proxy with an authorization
                                       * mechanism for administrative tasks.
                                       * All external functions in this contract must be guarded by the
                                       * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
                                       * feature proposal that would enable this to be done automatically.
                                       */
                                      contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
                                        /**
                                         * Contract constructor.
                                         * @param _logic address of the initial implementation.
                                         * @param _admin Address of the proxy administrator.
                                         * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
                                         * It should include the signature and the parameters of the function to be called, as described in
                                         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
                                         * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
                                         */
                                        constructor(address _logic, address _admin, bytes memory _data) UpgradeabilityProxy(_logic, _data) public payable {
                                          assert(ADMIN_SLOT == bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1));
                                          _setAdmin(_admin);
                                        }
                                        /**
                                         * @dev Emitted when the administration has been transferred.
                                         * @param previousAdmin Address of the previous admin.
                                         * @param newAdmin Address of the new admin.
                                         */
                                        event AdminChanged(address previousAdmin, address newAdmin);
                                        /**
                                         * @dev Storage slot with the admin of the contract.
                                         * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
                                         * validated in the constructor.
                                         */
                                        bytes32 internal constant ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;
                                        /**
                                         * @dev Modifier to check whether the `msg.sender` is the admin.
                                         * If it is, it will run the function. Otherwise, it will delegate the call
                                         * to the implementation.
                                         */
                                        modifier ifAdmin() {
                                          if (msg.sender == _admin()) {
                                            _;
                                          } else {
                                            _fallback();
                                          }
                                        }
                                        /**
                                         * @return The address of the proxy admin.
                                         */
                                        function admin() external ifAdmin returns (address) {
                                          return _admin();
                                        }
                                        /**
                                         * @return The address of the implementation.
                                         */
                                        function implementation() external ifAdmin returns (address) {
                                          return _implementation();
                                        }
                                        /**
                                         * @dev Changes the admin of the proxy.
                                         * Only the current admin can call this function.
                                         * @param newAdmin Address to transfer proxy administration to.
                                         */
                                        function changeAdmin(address newAdmin) external ifAdmin {
                                          require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
                                          emit AdminChanged(_admin(), newAdmin);
                                          _setAdmin(newAdmin);
                                        }
                                        /**
                                         * @dev Upgrade the backing implementation of the proxy.
                                         * Only the admin can call this function.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function upgradeTo(address newImplementation) external ifAdmin {
                                          _upgradeTo(newImplementation);
                                        }
                                        /**
                                         * @dev Upgrade the backing implementation of the proxy and call a function
                                         * on the new implementation.
                                         * This is useful to initialize the proxied contract.
                                         * @param newImplementation Address of the new implementation.
                                         * @param data Data to send as msg.data in the low level call.
                                         * It should include the signature and the parameters of the function to be called, as described in
                                         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
                                         */
                                        function upgradeToAndCall(address newImplementation, bytes calldata data) payable external ifAdmin {
                                          _upgradeTo(newImplementation);
                                          (bool success,) = newImplementation.delegatecall(data);
                                          require(success);
                                        }
                                        /**
                                         * @return adm The admin slot.
                                         */
                                        function _admin() internal view returns (address adm) {
                                          bytes32 slot = ADMIN_SLOT;
                                          assembly {
                                            adm := sload(slot)
                                          }
                                        }
                                        /**
                                         * @dev Sets the address of the proxy admin.
                                         * @param newAdmin Address of the new proxy admin.
                                         */
                                        function _setAdmin(address newAdmin) internal {
                                          bytes32 slot = ADMIN_SLOT;
                                          assembly {
                                            sstore(slot, newAdmin)
                                          }
                                        }
                                        /**
                                         * @dev Only fall back when the sender is not the admin.
                                         */
                                        function _willFallback() internal override virtual {
                                          require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
                                          super._willFallback();
                                        }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.6.0;
                                      import './Proxy.sol';
                                      import '@openzeppelin/contracts/utils/Address.sol';
                                      /**
                                       * @title UpgradeabilityProxy
                                       * @dev This contract implements a proxy that allows to change the
                                       * implementation address to which it will delegate.
                                       * Such a change is called an implementation upgrade.
                                       */
                                      contract UpgradeabilityProxy is Proxy {
                                        /**
                                         * @dev Contract constructor.
                                         * @param _logic Address of the initial implementation.
                                         * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
                                         * It should include the signature and the parameters of the function to be called, as described in
                                         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
                                         * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
                                         */
                                        constructor(address _logic, bytes memory _data) public payable {
                                          assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
                                          _setImplementation(_logic);
                                          if(_data.length > 0) {
                                            (bool success,) = _logic.delegatecall(_data);
                                            require(success);
                                          }
                                        }  
                                        /**
                                         * @dev Emitted when the implementation is upgraded.
                                         * @param implementation Address of the new implementation.
                                         */
                                        event Upgraded(address indexed implementation);
                                        /**
                                         * @dev Storage slot with the address of the current implementation.
                                         * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
                                         * validated in the constructor.
                                         */
                                        bytes32 internal constant IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
                                        /**
                                         * @dev Returns the current implementation.
                                         * @return impl Address of the current implementation
                                         */
                                        function _implementation() internal override view returns (address impl) {
                                          bytes32 slot = IMPLEMENTATION_SLOT;
                                          assembly {
                                            impl := sload(slot)
                                          }
                                        }
                                        /**
                                         * @dev Upgrades the proxy to a new implementation.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function _upgradeTo(address newImplementation) internal {
                                          _setImplementation(newImplementation);
                                          emit Upgraded(newImplementation);
                                        }
                                        /**
                                         * @dev Sets the implementation address of the proxy.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function _setImplementation(address newImplementation) internal {
                                          require(Address.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
                                          bytes32 slot = IMPLEMENTATION_SLOT;
                                          assembly {
                                            sstore(slot, newImplementation)
                                          }
                                        }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.6.0;
                                      /**
                                       * @title Proxy
                                       * @dev Implements delegation of calls to other contracts, with proper
                                       * forwarding of return values and bubbling of failures.
                                       * It defines a fallback function that delegates all calls to the address
                                       * returned by the abstract _implementation() internal function.
                                       */
                                      abstract contract Proxy {
                                        /**
                                         * @dev Fallback function.
                                         * Implemented entirely in `_fallback`.
                                         */
                                        fallback () payable external {
                                          _fallback();
                                        }
                                        /**
                                         * @dev Receive function.
                                         * Implemented entirely in `_fallback`.
                                         */
                                        receive () payable external {
                                          _fallback();
                                        }
                                        /**
                                         * @return The Address of the implementation.
                                         */
                                        function _implementation() internal virtual view returns (address);
                                        /**
                                         * @dev Delegates execution to an implementation contract.
                                         * This is a low level function that doesn't return to its internal call site.
                                         * It will return to the external caller whatever the implementation returns.
                                         * @param implementation Address to delegate.
                                         */
                                        function _delegate(address implementation) internal {
                                          assembly {
                                            // Copy msg.data. We take full control of memory in this inline assembly
                                            // block because it will not return to Solidity code. We overwrite the
                                            // Solidity scratch pad at memory position 0.
                                            calldatacopy(0, 0, calldatasize())
                                            // Call the implementation.
                                            // out and outsize are 0 because we don't know the size yet.
                                            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)
                                            // Copy the returned data.
                                            returndatacopy(0, 0, returndatasize())
                                            switch result
                                            // delegatecall returns 0 on error.
                                            case 0 { revert(0, returndatasize()) }
                                            default { return(0, returndatasize()) }
                                          }
                                        }
                                        /**
                                         * @dev Function that is run as the first thing in the fallback function.
                                         * Can be redefined in derived contracts to add functionality.
                                         * Redefinitions must call super._willFallback().
                                         */
                                        function _willFallback() internal virtual {
                                        }
                                        /**
                                         * @dev fallback implementation.
                                         * Extracted to enable manual triggering.
                                         */
                                        function _fallback() internal {
                                          _willFallback();
                                          _delegate(_implementation());
                                        }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity >=0.6.2 <0.8.0;
                                      /**
                                       * @dev Collection of functions related to the address type
                                       */
                                      library Address {
                                          /**
                                           * @dev Returns true if `account` is a contract.
                                           *
                                           * [IMPORTANT]
                                           * ====
                                           * It is unsafe to assume that an address for which this function returns
                                           * false is an externally-owned account (EOA) and not a contract.
                                           *
                                           * Among others, `isContract` will return false for the following
                                           * types of addresses:
                                           *
                                           *  - an externally-owned account
                                           *  - a contract in construction
                                           *  - an address where a contract will be created
                                           *  - an address where a contract lived, but was destroyed
                                           * ====
                                           */
                                          function isContract(address account) internal view returns (bool) {
                                              // This method relies on extcodesize, which returns 0 for contracts in
                                              // construction, since the code is only stored at the end of the
                                              // constructor execution.
                                              uint256 size;
                                              // solhint-disable-next-line no-inline-assembly
                                              assembly { size := extcodesize(account) }
                                              return size > 0;
                                          }
                                          /**
                                           * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                                           * `recipient`, forwarding all available gas and reverting on errors.
                                           *
                                           * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                                           * of certain opcodes, possibly making contracts go over the 2300 gas limit
                                           * imposed by `transfer`, making them unable to receive funds via
                                           * `transfer`. {sendValue} removes this limitation.
                                           *
                                           * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                                           *
                                           * IMPORTANT: because control is transferred to `recipient`, care must be
                                           * taken to not create reentrancy vulnerabilities. Consider using
                                           * {ReentrancyGuard} or the
                                           * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                                           */
                                          function sendValue(address payable recipient, uint256 amount) internal {
                                              require(address(this).balance >= amount, "Address: insufficient balance");
                                              // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                                              (bool success, ) = recipient.call{ value: amount }("");
                                              require(success, "Address: unable to send value, recipient may have reverted");
                                          }
                                          /**
                                           * @dev Performs a Solidity function call using a low level `call`. A
                                           * plain`call` is an unsafe replacement for a function call: use this
                                           * function instead.
                                           *
                                           * If `target` reverts with a revert reason, it is bubbled up by this
                                           * function (like regular Solidity function calls).
                                           *
                                           * Returns the raw returned data. To convert to the expected return value,
                                           * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                                           *
                                           * Requirements:
                                           *
                                           * - `target` must be a contract.
                                           * - calling `target` with `data` must not revert.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                                            return functionCall(target, data, "Address: low-level call failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                                           * `errorMessage` as a fallback revert reason when `target` reverts.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                                              return functionCallWithValue(target, data, 0, errorMessage);
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                                           * but also transferring `value` wei to `target`.
                                           *
                                           * Requirements:
                                           *
                                           * - the calling contract must have an ETH balance of at least `value`.
                                           * - the called Solidity function must be `payable`.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                                              return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                                           * with `errorMessage` as a fallback revert reason when `target` reverts.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                                              require(address(this).balance >= value, "Address: insufficient balance for call");
                                              require(isContract(target), "Address: call to non-contract");
                                              // solhint-disable-next-line avoid-low-level-calls
                                              (bool success, bytes memory returndata) = target.call{ value: value }(data);
                                              return _verifyCallResult(success, returndata, errorMessage);
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                                           * but performing a static call.
                                           *
                                           * _Available since v3.3._
                                           */
                                          function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                                              return functionStaticCall(target, data, "Address: low-level static call failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                                           * but performing a static call.
                                           *
                                           * _Available since v3.3._
                                           */
                                          function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                                              require(isContract(target), "Address: static call to non-contract");
                                              // solhint-disable-next-line avoid-low-level-calls
                                              (bool success, bytes memory returndata) = target.staticcall(data);
                                              return _verifyCallResult(success, returndata, errorMessage);
                                          }
                                          function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                                              if (success) {
                                                  return returndata;
                                              } else {
                                                  // Look for revert reason and bubble it up if present
                                                  if (returndata.length > 0) {
                                                      // The easiest way to bubble the revert reason is using memory via assembly
                                                      // solhint-disable-next-line no-inline-assembly
                                                      assembly {
                                                          let returndata_size := mload(returndata)
                                                          revert(add(32, returndata), returndata_size)
                                                      }
                                                  } else {
                                                      revert(errorMessage);
                                                  }
                                              }
                                          }
                                      }
                                      

                                      File 3 of 11: FiatTokenProxy
                                      pragma solidity ^0.4.24;
                                      
                                      // File: zos-lib/contracts/upgradeability/Proxy.sol
                                      
                                      /**
                                       * @title Proxy
                                       * @dev Implements delegation of calls to other contracts, with proper
                                       * forwarding of return values and bubbling of failures.
                                       * It defines a fallback function that delegates all calls to the address
                                       * returned by the abstract _implementation() internal function.
                                       */
                                      contract Proxy {
                                        /**
                                         * @dev Fallback function.
                                         * Implemented entirely in `_fallback`.
                                         */
                                        function () payable external {
                                          _fallback();
                                        }
                                      
                                        /**
                                         * @return The Address of the implementation.
                                         */
                                        function _implementation() internal view returns (address);
                                      
                                        /**
                                         * @dev Delegates execution to an implementation contract.
                                         * This is a low level function that doesn't return to its internal call site.
                                         * It will return to the external caller whatever the implementation returns.
                                         * @param implementation Address to delegate.
                                         */
                                        function _delegate(address implementation) internal {
                                          assembly {
                                            // Copy msg.data. We take full control of memory in this inline assembly
                                            // block because it will not return to Solidity code. We overwrite the
                                            // Solidity scratch pad at memory position 0.
                                            calldatacopy(0, 0, calldatasize)
                                      
                                            // Call the implementation.
                                            // out and outsize are 0 because we don't know the size yet.
                                            let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
                                      
                                            // Copy the returned data.
                                            returndatacopy(0, 0, returndatasize)
                                      
                                            switch result
                                            // delegatecall returns 0 on error.
                                            case 0 { revert(0, returndatasize) }
                                            default { return(0, returndatasize) }
                                          }
                                        }
                                      
                                        /**
                                         * @dev Function that is run as the first thing in the fallback function.
                                         * Can be redefined in derived contracts to add functionality.
                                         * Redefinitions must call super._willFallback().
                                         */
                                        function _willFallback() internal {
                                        }
                                      
                                        /**
                                         * @dev fallback implementation.
                                         * Extracted to enable manual triggering.
                                         */
                                        function _fallback() internal {
                                          _willFallback();
                                          _delegate(_implementation());
                                        }
                                      }
                                      
                                      // File: openzeppelin-solidity/contracts/AddressUtils.sol
                                      
                                      /**
                                       * Utility library of inline functions on addresses
                                       */
                                      library AddressUtils {
                                      
                                        /**
                                         * Returns whether the target address is a contract
                                         * @dev This function will return false if invoked during the constructor of a contract,
                                         * as the code is not actually created until after the constructor finishes.
                                         * @param addr address to check
                                         * @return whether the target address is a contract
                                         */
                                        function isContract(address addr) internal view returns (bool) {
                                          uint256 size;
                                          // XXX Currently there is no better way to check if there is a contract in an address
                                          // than to check the size of the code at that address.
                                          // See https://ethereum.stackexchange.com/a/14016/36603
                                          // for more details about how this works.
                                          // TODO Check this again before the Serenity release, because all addresses will be
                                          // contracts then.
                                          // solium-disable-next-line security/no-inline-assembly
                                          assembly { size := extcodesize(addr) }
                                          return size > 0;
                                        }
                                      
                                      }
                                      
                                      // File: zos-lib/contracts/upgradeability/UpgradeabilityProxy.sol
                                      
                                      /**
                                       * @title UpgradeabilityProxy
                                       * @dev This contract implements a proxy that allows to change the
                                       * implementation address to which it will delegate.
                                       * Such a change is called an implementation upgrade.
                                       */
                                      contract UpgradeabilityProxy is Proxy {
                                        /**
                                         * @dev Emitted when the implementation is upgraded.
                                         * @param implementation Address of the new implementation.
                                         */
                                        event Upgraded(address implementation);
                                      
                                        /**
                                         * @dev Storage slot with the address of the current implementation.
                                         * This is the keccak-256 hash of "org.zeppelinos.proxy.implementation", and is
                                         * validated in the constructor.
                                         */
                                        bytes32 private constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;
                                      
                                        /**
                                         * @dev Contract constructor.
                                         * @param _implementation Address of the initial implementation.
                                         */
                                        constructor(address _implementation) public {
                                          assert(IMPLEMENTATION_SLOT == keccak256("org.zeppelinos.proxy.implementation"));
                                      
                                          _setImplementation(_implementation);
                                        }
                                      
                                        /**
                                         * @dev Returns the current implementation.
                                         * @return Address of the current implementation
                                         */
                                        function _implementation() internal view returns (address impl) {
                                          bytes32 slot = IMPLEMENTATION_SLOT;
                                          assembly {
                                            impl := sload(slot)
                                          }
                                        }
                                      
                                        /**
                                         * @dev Upgrades the proxy to a new implementation.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function _upgradeTo(address newImplementation) internal {
                                          _setImplementation(newImplementation);
                                          emit Upgraded(newImplementation);
                                        }
                                      
                                        /**
                                         * @dev Sets the implementation address of the proxy.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function _setImplementation(address newImplementation) private {
                                          require(AddressUtils.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
                                      
                                          bytes32 slot = IMPLEMENTATION_SLOT;
                                      
                                          assembly {
                                            sstore(slot, newImplementation)
                                          }
                                        }
                                      }
                                      
                                      // File: zos-lib/contracts/upgradeability/AdminUpgradeabilityProxy.sol
                                      
                                      /**
                                       * @title AdminUpgradeabilityProxy
                                       * @dev This contract combines an upgradeability proxy with an authorization
                                       * mechanism for administrative tasks.
                                       * All external functions in this contract must be guarded by the
                                       * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
                                       * feature proposal that would enable this to be done automatically.
                                       */
                                      contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
                                        /**
                                         * @dev Emitted when the administration has been transferred.
                                         * @param previousAdmin Address of the previous admin.
                                         * @param newAdmin Address of the new admin.
                                         */
                                        event AdminChanged(address previousAdmin, address newAdmin);
                                      
                                        /**
                                         * @dev Storage slot with the admin of the contract.
                                         * This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
                                         * validated in the constructor.
                                         */
                                        bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;
                                      
                                        /**
                                         * @dev Modifier to check whether the `msg.sender` is the admin.
                                         * If it is, it will run the function. Otherwise, it will delegate the call
                                         * to the implementation.
                                         */
                                        modifier ifAdmin() {
                                          if (msg.sender == _admin()) {
                                            _;
                                          } else {
                                            _fallback();
                                          }
                                        }
                                      
                                        /**
                                         * Contract constructor.
                                         * It sets the `msg.sender` as the proxy administrator.
                                         * @param _implementation address of the initial implementation.
                                         */
                                        constructor(address _implementation) UpgradeabilityProxy(_implementation) public {
                                          assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));
                                      
                                          _setAdmin(msg.sender);
                                        }
                                      
                                        /**
                                         * @return The address of the proxy admin.
                                         */
                                        function admin() external view ifAdmin returns (address) {
                                          return _admin();
                                        }
                                      
                                        /**
                                         * @return The address of the implementation.
                                         */
                                        function implementation() external view ifAdmin returns (address) {
                                          return _implementation();
                                        }
                                      
                                        /**
                                         * @dev Changes the admin of the proxy.
                                         * Only the current admin can call this function.
                                         * @param newAdmin Address to transfer proxy administration to.
                                         */
                                        function changeAdmin(address newAdmin) external ifAdmin {
                                          require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
                                          emit AdminChanged(_admin(), newAdmin);
                                          _setAdmin(newAdmin);
                                        }
                                      
                                        /**
                                         * @dev Upgrade the backing implementation of the proxy.
                                         * Only the admin can call this function.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function upgradeTo(address newImplementation) external ifAdmin {
                                          _upgradeTo(newImplementation);
                                        }
                                      
                                        /**
                                         * @dev Upgrade the backing implementation of the proxy and call a function
                                         * on the new implementation.
                                         * This is useful to initialize the proxied contract.
                                         * @param newImplementation Address of the new implementation.
                                         * @param data Data to send as msg.data in the low level call.
                                         * It should include the signature and the parameters of the function to be
                                         * called, as described in
                                         * https://solidity.readthedocs.io/en/develop/abi-spec.html#function-selector-and-argument-encoding.
                                         */
                                        function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
                                          _upgradeTo(newImplementation);
                                          require(address(this).call.value(msg.value)(data));
                                        }
                                      
                                        /**
                                         * @return The admin slot.
                                         */
                                        function _admin() internal view returns (address adm) {
                                          bytes32 slot = ADMIN_SLOT;
                                          assembly {
                                            adm := sload(slot)
                                          }
                                        }
                                      
                                        /**
                                         * @dev Sets the address of the proxy admin.
                                         * @param newAdmin Address of the new proxy admin.
                                         */
                                        function _setAdmin(address newAdmin) internal {
                                          bytes32 slot = ADMIN_SLOT;
                                      
                                          assembly {
                                            sstore(slot, newAdmin)
                                          }
                                        }
                                      
                                        /**
                                         * @dev Only fall back when the sender is not the admin.
                                         */
                                        function _willFallback() internal {
                                          require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
                                          super._willFallback();
                                        }
                                      }
                                      
                                      // File: contracts/FiatTokenProxy.sol
                                      
                                      /**
                                      * Copyright CENTRE SECZ 2018
                                      *
                                      * Permission is hereby granted, free of charge, to any person obtaining a copy 
                                      * of this software and associated documentation files (the "Software"), to deal 
                                      * in the Software without restriction, including without limitation the rights 
                                      * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
                                      * copies of the Software, and to permit persons to whom the Software is furnished to 
                                      * do so, subject to the following conditions:
                                      *
                                      * The above copyright notice and this permission notice shall be included in all 
                                      * copies or substantial portions of the Software.
                                      *
                                      * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
                                      * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
                                      * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
                                      * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
                                      * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 
                                      * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
                                      */
                                      
                                      pragma solidity ^0.4.24;
                                      
                                      
                                      /**
                                       * @title FiatTokenProxy
                                       * @dev This contract proxies FiatToken calls and enables FiatToken upgrades
                                      */ 
                                      contract FiatTokenProxy is AdminUpgradeabilityProxy {
                                          constructor(address _implementation) public AdminUpgradeabilityProxy(_implementation) {
                                          }
                                      }

                                      File 4 of 11: UniswapV3Pool
                                      // SPDX-License-Identifier: BUSL-1.1
                                      pragma solidity =0.7.6;
                                      import './interfaces/IUniswapV3Pool.sol';
                                      import './NoDelegateCall.sol';
                                      import './libraries/LowGasSafeMath.sol';
                                      import './libraries/SafeCast.sol';
                                      import './libraries/Tick.sol';
                                      import './libraries/TickBitmap.sol';
                                      import './libraries/Position.sol';
                                      import './libraries/Oracle.sol';
                                      import './libraries/FullMath.sol';
                                      import './libraries/FixedPoint128.sol';
                                      import './libraries/TransferHelper.sol';
                                      import './libraries/TickMath.sol';
                                      import './libraries/LiquidityMath.sol';
                                      import './libraries/SqrtPriceMath.sol';
                                      import './libraries/SwapMath.sol';
                                      import './interfaces/IUniswapV3PoolDeployer.sol';
                                      import './interfaces/IUniswapV3Factory.sol';
                                      import './interfaces/IERC20Minimal.sol';
                                      import './interfaces/callback/IUniswapV3MintCallback.sol';
                                      import './interfaces/callback/IUniswapV3SwapCallback.sol';
                                      import './interfaces/callback/IUniswapV3FlashCallback.sol';
                                      contract UniswapV3Pool is IUniswapV3Pool, NoDelegateCall {
                                          using LowGasSafeMath for uint256;
                                          using LowGasSafeMath for int256;
                                          using SafeCast for uint256;
                                          using SafeCast for int256;
                                          using Tick for mapping(int24 => Tick.Info);
                                          using TickBitmap for mapping(int16 => uint256);
                                          using Position for mapping(bytes32 => Position.Info);
                                          using Position for Position.Info;
                                          using Oracle for Oracle.Observation[65535];
                                          /// @inheritdoc IUniswapV3PoolImmutables
                                          address public immutable override factory;
                                          /// @inheritdoc IUniswapV3PoolImmutables
                                          address public immutable override token0;
                                          /// @inheritdoc IUniswapV3PoolImmutables
                                          address public immutable override token1;
                                          /// @inheritdoc IUniswapV3PoolImmutables
                                          uint24 public immutable override fee;
                                          /// @inheritdoc IUniswapV3PoolImmutables
                                          int24 public immutable override tickSpacing;
                                          /// @inheritdoc IUniswapV3PoolImmutables
                                          uint128 public immutable override maxLiquidityPerTick;
                                          struct Slot0 {
                                              // the current price
                                              uint160 sqrtPriceX96;
                                              // the current tick
                                              int24 tick;
                                              // the most-recently updated index of the observations array
                                              uint16 observationIndex;
                                              // the current maximum number of observations that are being stored
                                              uint16 observationCardinality;
                                              // the next maximum number of observations to store, triggered in observations.write
                                              uint16 observationCardinalityNext;
                                              // the current protocol fee as a percentage of the swap fee taken on withdrawal
                                              // represented as an integer denominator (1/x)%
                                              uint8 feeProtocol;
                                              // whether the pool is locked
                                              bool unlocked;
                                          }
                                          /// @inheritdoc IUniswapV3PoolState
                                          Slot0 public override slot0;
                                          /// @inheritdoc IUniswapV3PoolState
                                          uint256 public override feeGrowthGlobal0X128;
                                          /// @inheritdoc IUniswapV3PoolState
                                          uint256 public override feeGrowthGlobal1X128;
                                          // accumulated protocol fees in token0/token1 units
                                          struct ProtocolFees {
                                              uint128 token0;
                                              uint128 token1;
                                          }
                                          /// @inheritdoc IUniswapV3PoolState
                                          ProtocolFees public override protocolFees;
                                          /// @inheritdoc IUniswapV3PoolState
                                          uint128 public override liquidity;
                                          /// @inheritdoc IUniswapV3PoolState
                                          mapping(int24 => Tick.Info) public override ticks;
                                          /// @inheritdoc IUniswapV3PoolState
                                          mapping(int16 => uint256) public override tickBitmap;
                                          /// @inheritdoc IUniswapV3PoolState
                                          mapping(bytes32 => Position.Info) public override positions;
                                          /// @inheritdoc IUniswapV3PoolState
                                          Oracle.Observation[65535] public override observations;
                                          /// @dev Mutually exclusive reentrancy protection into the pool to/from a method. This method also prevents entrance
                                          /// to a function before the pool is initialized. The reentrancy guard is required throughout the contract because
                                          /// we use balance checks to determine the payment status of interactions such as mint, swap and flash.
                                          modifier lock() {
                                              require(slot0.unlocked, 'LOK');
                                              slot0.unlocked = false;
                                              _;
                                              slot0.unlocked = true;
                                          }
                                          /// @dev Prevents calling a function from anyone except the address returned by IUniswapV3Factory#owner()
                                          modifier onlyFactoryOwner() {
                                              require(msg.sender == IUniswapV3Factory(factory).owner());
                                              _;
                                          }
                                          constructor() {
                                              int24 _tickSpacing;
                                              (factory, token0, token1, fee, _tickSpacing) = IUniswapV3PoolDeployer(msg.sender).parameters();
                                              tickSpacing = _tickSpacing;
                                              maxLiquidityPerTick = Tick.tickSpacingToMaxLiquidityPerTick(_tickSpacing);
                                          }
                                          /// @dev Common checks for valid tick inputs.
                                          function checkTicks(int24 tickLower, int24 tickUpper) private pure {
                                              require(tickLower < tickUpper, 'TLU');
                                              require(tickLower >= TickMath.MIN_TICK, 'TLM');
                                              require(tickUpper <= TickMath.MAX_TICK, 'TUM');
                                          }
                                          /// @dev Returns the block timestamp truncated to 32 bits, i.e. mod 2**32. This method is overridden in tests.
                                          function _blockTimestamp() internal view virtual returns (uint32) {
                                              return uint32(block.timestamp); // truncation is desired
                                          }
                                          /// @dev Get the pool's balance of token0
                                          /// @dev This function is gas optimized to avoid a redundant extcodesize check in addition to the returndatasize
                                          /// check
                                          function balance0() private view returns (uint256) {
                                              (bool success, bytes memory data) =
                                                  token0.staticcall(abi.encodeWithSelector(IERC20Minimal.balanceOf.selector, address(this)));
                                              require(success && data.length >= 32);
                                              return abi.decode(data, (uint256));
                                          }
                                          /// @dev Get the pool's balance of token1
                                          /// @dev This function is gas optimized to avoid a redundant extcodesize check in addition to the returndatasize
                                          /// check
                                          function balance1() private view returns (uint256) {
                                              (bool success, bytes memory data) =
                                                  token1.staticcall(abi.encodeWithSelector(IERC20Minimal.balanceOf.selector, address(this)));
                                              require(success && data.length >= 32);
                                              return abi.decode(data, (uint256));
                                          }
                                          /// @inheritdoc IUniswapV3PoolDerivedState
                                          function snapshotCumulativesInside(int24 tickLower, int24 tickUpper)
                                              external
                                              view
                                              override
                                              noDelegateCall
                                              returns (
                                                  int56 tickCumulativeInside,
                                                  uint160 secondsPerLiquidityInsideX128,
                                                  uint32 secondsInside
                                              )
                                          {
                                              checkTicks(tickLower, tickUpper);
                                              int56 tickCumulativeLower;
                                              int56 tickCumulativeUpper;
                                              uint160 secondsPerLiquidityOutsideLowerX128;
                                              uint160 secondsPerLiquidityOutsideUpperX128;
                                              uint32 secondsOutsideLower;
                                              uint32 secondsOutsideUpper;
                                              {
                                                  Tick.Info storage lower = ticks[tickLower];
                                                  Tick.Info storage upper = ticks[tickUpper];
                                                  bool initializedLower;
                                                  (tickCumulativeLower, secondsPerLiquidityOutsideLowerX128, secondsOutsideLower, initializedLower) = (
                                                      lower.tickCumulativeOutside,
                                                      lower.secondsPerLiquidityOutsideX128,
                                                      lower.secondsOutside,
                                                      lower.initialized
                                                  );
                                                  require(initializedLower);
                                                  bool initializedUpper;
                                                  (tickCumulativeUpper, secondsPerLiquidityOutsideUpperX128, secondsOutsideUpper, initializedUpper) = (
                                                      upper.tickCumulativeOutside,
                                                      upper.secondsPerLiquidityOutsideX128,
                                                      upper.secondsOutside,
                                                      upper.initialized
                                                  );
                                                  require(initializedUpper);
                                              }
                                              Slot0 memory _slot0 = slot0;
                                              if (_slot0.tick < tickLower) {
                                                  return (
                                                      tickCumulativeLower - tickCumulativeUpper,
                                                      secondsPerLiquidityOutsideLowerX128 - secondsPerLiquidityOutsideUpperX128,
                                                      secondsOutsideLower - secondsOutsideUpper
                                                  );
                                              } else if (_slot0.tick < tickUpper) {
                                                  uint32 time = _blockTimestamp();
                                                  (int56 tickCumulative, uint160 secondsPerLiquidityCumulativeX128) =
                                                      observations.observeSingle(
                                                          time,
                                                          0,
                                                          _slot0.tick,
                                                          _slot0.observationIndex,
                                                          liquidity,
                                                          _slot0.observationCardinality
                                                      );
                                                  return (
                                                      tickCumulative - tickCumulativeLower - tickCumulativeUpper,
                                                      secondsPerLiquidityCumulativeX128 -
                                                          secondsPerLiquidityOutsideLowerX128 -
                                                          secondsPerLiquidityOutsideUpperX128,
                                                      time - secondsOutsideLower - secondsOutsideUpper
                                                  );
                                              } else {
                                                  return (
                                                      tickCumulativeUpper - tickCumulativeLower,
                                                      secondsPerLiquidityOutsideUpperX128 - secondsPerLiquidityOutsideLowerX128,
                                                      secondsOutsideUpper - secondsOutsideLower
                                                  );
                                              }
                                          }
                                          /// @inheritdoc IUniswapV3PoolDerivedState
                                          function observe(uint32[] calldata secondsAgos)
                                              external
                                              view
                                              override
                                              noDelegateCall
                                              returns (int56[] memory tickCumulatives, uint160[] memory secondsPerLiquidityCumulativeX128s)
                                          {
                                              return
                                                  observations.observe(
                                                      _blockTimestamp(),
                                                      secondsAgos,
                                                      slot0.tick,
                                                      slot0.observationIndex,
                                                      liquidity,
                                                      slot0.observationCardinality
                                                  );
                                          }
                                          /// @inheritdoc IUniswapV3PoolActions
                                          function increaseObservationCardinalityNext(uint16 observationCardinalityNext)
                                              external
                                              override
                                              lock
                                              noDelegateCall
                                          {
                                              uint16 observationCardinalityNextOld = slot0.observationCardinalityNext; // for the event
                                              uint16 observationCardinalityNextNew =
                                                  observations.grow(observationCardinalityNextOld, observationCardinalityNext);
                                              slot0.observationCardinalityNext = observationCardinalityNextNew;
                                              if (observationCardinalityNextOld != observationCardinalityNextNew)
                                                  emit IncreaseObservationCardinalityNext(observationCardinalityNextOld, observationCardinalityNextNew);
                                          }
                                          /// @inheritdoc IUniswapV3PoolActions
                                          /// @dev not locked because it initializes unlocked
                                          function initialize(uint160 sqrtPriceX96) external override {
                                              require(slot0.sqrtPriceX96 == 0, 'AI');
                                              int24 tick = TickMath.getTickAtSqrtRatio(sqrtPriceX96);
                                              (uint16 cardinality, uint16 cardinalityNext) = observations.initialize(_blockTimestamp());
                                              slot0 = Slot0({
                                                  sqrtPriceX96: sqrtPriceX96,
                                                  tick: tick,
                                                  observationIndex: 0,
                                                  observationCardinality: cardinality,
                                                  observationCardinalityNext: cardinalityNext,
                                                  feeProtocol: 0,
                                                  unlocked: true
                                              });
                                              emit Initialize(sqrtPriceX96, tick);
                                          }
                                          struct ModifyPositionParams {
                                              // the address that owns the position
                                              address owner;
                                              // the lower and upper tick of the position
                                              int24 tickLower;
                                              int24 tickUpper;
                                              // any change in liquidity
                                              int128 liquidityDelta;
                                          }
                                          /// @dev Effect some changes to a position
                                          /// @param params the position details and the change to the position's liquidity to effect
                                          /// @return position a storage pointer referencing the position with the given owner and tick range
                                          /// @return amount0 the amount of token0 owed to the pool, negative if the pool should pay the recipient
                                          /// @return amount1 the amount of token1 owed to the pool, negative if the pool should pay the recipient
                                          function _modifyPosition(ModifyPositionParams memory params)
                                              private
                                              noDelegateCall
                                              returns (
                                                  Position.Info storage position,
                                                  int256 amount0,
                                                  int256 amount1
                                              )
                                          {
                                              checkTicks(params.tickLower, params.tickUpper);
                                              Slot0 memory _slot0 = slot0; // SLOAD for gas optimization
                                              position = _updatePosition(
                                                  params.owner,
                                                  params.tickLower,
                                                  params.tickUpper,
                                                  params.liquidityDelta,
                                                  _slot0.tick
                                              );
                                              if (params.liquidityDelta != 0) {
                                                  if (_slot0.tick < params.tickLower) {
                                                      // current tick is below the passed range; liquidity can only become in range by crossing from left to
                                                      // right, when we'll need _more_ token0 (it's becoming more valuable) so user must provide it
                                                      amount0 = SqrtPriceMath.getAmount0Delta(
                                                          TickMath.getSqrtRatioAtTick(params.tickLower),
                                                          TickMath.getSqrtRatioAtTick(params.tickUpper),
                                                          params.liquidityDelta
                                                      );
                                                  } else if (_slot0.tick < params.tickUpper) {
                                                      // current tick is inside the passed range
                                                      uint128 liquidityBefore = liquidity; // SLOAD for gas optimization
                                                      // write an oracle entry
                                                      (slot0.observationIndex, slot0.observationCardinality) = observations.write(
                                                          _slot0.observationIndex,
                                                          _blockTimestamp(),
                                                          _slot0.tick,
                                                          liquidityBefore,
                                                          _slot0.observationCardinality,
                                                          _slot0.observationCardinalityNext
                                                      );
                                                      amount0 = SqrtPriceMath.getAmount0Delta(
                                                          _slot0.sqrtPriceX96,
                                                          TickMath.getSqrtRatioAtTick(params.tickUpper),
                                                          params.liquidityDelta
                                                      );
                                                      amount1 = SqrtPriceMath.getAmount1Delta(
                                                          TickMath.getSqrtRatioAtTick(params.tickLower),
                                                          _slot0.sqrtPriceX96,
                                                          params.liquidityDelta
                                                      );
                                                      liquidity = LiquidityMath.addDelta(liquidityBefore, params.liquidityDelta);
                                                  } else {
                                                      // current tick is above the passed range; liquidity can only become in range by crossing from right to
                                                      // left, when we'll need _more_ token1 (it's becoming more valuable) so user must provide it
                                                      amount1 = SqrtPriceMath.getAmount1Delta(
                                                          TickMath.getSqrtRatioAtTick(params.tickLower),
                                                          TickMath.getSqrtRatioAtTick(params.tickUpper),
                                                          params.liquidityDelta
                                                      );
                                                  }
                                              }
                                          }
                                          /// @dev Gets and updates a position with the given liquidity delta
                                          /// @param owner the owner of the position
                                          /// @param tickLower the lower tick of the position's tick range
                                          /// @param tickUpper the upper tick of the position's tick range
                                          /// @param tick the current tick, passed to avoid sloads
                                          function _updatePosition(
                                              address owner,
                                              int24 tickLower,
                                              int24 tickUpper,
                                              int128 liquidityDelta,
                                              int24 tick
                                          ) private returns (Position.Info storage position) {
                                              position = positions.get(owner, tickLower, tickUpper);
                                              uint256 _feeGrowthGlobal0X128 = feeGrowthGlobal0X128; // SLOAD for gas optimization
                                              uint256 _feeGrowthGlobal1X128 = feeGrowthGlobal1X128; // SLOAD for gas optimization
                                              // if we need to update the ticks, do it
                                              bool flippedLower;
                                              bool flippedUpper;
                                              if (liquidityDelta != 0) {
                                                  uint32 time = _blockTimestamp();
                                                  (int56 tickCumulative, uint160 secondsPerLiquidityCumulativeX128) =
                                                      observations.observeSingle(
                                                          time,
                                                          0,
                                                          slot0.tick,
                                                          slot0.observationIndex,
                                                          liquidity,
                                                          slot0.observationCardinality
                                                      );
                                                  flippedLower = ticks.update(
                                                      tickLower,
                                                      tick,
                                                      liquidityDelta,
                                                      _feeGrowthGlobal0X128,
                                                      _feeGrowthGlobal1X128,
                                                      secondsPerLiquidityCumulativeX128,
                                                      tickCumulative,
                                                      time,
                                                      false,
                                                      maxLiquidityPerTick
                                                  );
                                                  flippedUpper = ticks.update(
                                                      tickUpper,
                                                      tick,
                                                      liquidityDelta,
                                                      _feeGrowthGlobal0X128,
                                                      _feeGrowthGlobal1X128,
                                                      secondsPerLiquidityCumulativeX128,
                                                      tickCumulative,
                                                      time,
                                                      true,
                                                      maxLiquidityPerTick
                                                  );
                                                  if (flippedLower) {
                                                      tickBitmap.flipTick(tickLower, tickSpacing);
                                                  }
                                                  if (flippedUpper) {
                                                      tickBitmap.flipTick(tickUpper, tickSpacing);
                                                  }
                                              }
                                              (uint256 feeGrowthInside0X128, uint256 feeGrowthInside1X128) =
                                                  ticks.getFeeGrowthInside(tickLower, tickUpper, tick, _feeGrowthGlobal0X128, _feeGrowthGlobal1X128);
                                              position.update(liquidityDelta, feeGrowthInside0X128, feeGrowthInside1X128);
                                              // clear any tick data that is no longer needed
                                              if (liquidityDelta < 0) {
                                                  if (flippedLower) {
                                                      ticks.clear(tickLower);
                                                  }
                                                  if (flippedUpper) {
                                                      ticks.clear(tickUpper);
                                                  }
                                              }
                                          }
                                          /// @inheritdoc IUniswapV3PoolActions
                                          /// @dev noDelegateCall is applied indirectly via _modifyPosition
                                          function mint(
                                              address recipient,
                                              int24 tickLower,
                                              int24 tickUpper,
                                              uint128 amount,
                                              bytes calldata data
                                          ) external override lock returns (uint256 amount0, uint256 amount1) {
                                              require(amount > 0);
                                              (, int256 amount0Int, int256 amount1Int) =
                                                  _modifyPosition(
                                                      ModifyPositionParams({
                                                          owner: recipient,
                                                          tickLower: tickLower,
                                                          tickUpper: tickUpper,
                                                          liquidityDelta: int256(amount).toInt128()
                                                      })
                                                  );
                                              amount0 = uint256(amount0Int);
                                              amount1 = uint256(amount1Int);
                                              uint256 balance0Before;
                                              uint256 balance1Before;
                                              if (amount0 > 0) balance0Before = balance0();
                                              if (amount1 > 0) balance1Before = balance1();
                                              IUniswapV3MintCallback(msg.sender).uniswapV3MintCallback(amount0, amount1, data);
                                              if (amount0 > 0) require(balance0Before.add(amount0) <= balance0(), 'M0');
                                              if (amount1 > 0) require(balance1Before.add(amount1) <= balance1(), 'M1');
                                              emit Mint(msg.sender, recipient, tickLower, tickUpper, amount, amount0, amount1);
                                          }
                                          /// @inheritdoc IUniswapV3PoolActions
                                          function collect(
                                              address recipient,
                                              int24 tickLower,
                                              int24 tickUpper,
                                              uint128 amount0Requested,
                                              uint128 amount1Requested
                                          ) external override lock returns (uint128 amount0, uint128 amount1) {
                                              // we don't need to checkTicks here, because invalid positions will never have non-zero tokensOwed{0,1}
                                              Position.Info storage position = positions.get(msg.sender, tickLower, tickUpper);
                                              amount0 = amount0Requested > position.tokensOwed0 ? position.tokensOwed0 : amount0Requested;
                                              amount1 = amount1Requested > position.tokensOwed1 ? position.tokensOwed1 : amount1Requested;
                                              if (amount0 > 0) {
                                                  position.tokensOwed0 -= amount0;
                                                  TransferHelper.safeTransfer(token0, recipient, amount0);
                                              }
                                              if (amount1 > 0) {
                                                  position.tokensOwed1 -= amount1;
                                                  TransferHelper.safeTransfer(token1, recipient, amount1);
                                              }
                                              emit Collect(msg.sender, recipient, tickLower, tickUpper, amount0, amount1);
                                          }
                                          /// @inheritdoc IUniswapV3PoolActions
                                          /// @dev noDelegateCall is applied indirectly via _modifyPosition
                                          function burn(
                                              int24 tickLower,
                                              int24 tickUpper,
                                              uint128 amount
                                          ) external override lock returns (uint256 amount0, uint256 amount1) {
                                              (Position.Info storage position, int256 amount0Int, int256 amount1Int) =
                                                  _modifyPosition(
                                                      ModifyPositionParams({
                                                          owner: msg.sender,
                                                          tickLower: tickLower,
                                                          tickUpper: tickUpper,
                                                          liquidityDelta: -int256(amount).toInt128()
                                                      })
                                                  );
                                              amount0 = uint256(-amount0Int);
                                              amount1 = uint256(-amount1Int);
                                              if (amount0 > 0 || amount1 > 0) {
                                                  (position.tokensOwed0, position.tokensOwed1) = (
                                                      position.tokensOwed0 + uint128(amount0),
                                                      position.tokensOwed1 + uint128(amount1)
                                                  );
                                              }
                                              emit Burn(msg.sender, tickLower, tickUpper, amount, amount0, amount1);
                                          }
                                          struct SwapCache {
                                              // the protocol fee for the input token
                                              uint8 feeProtocol;
                                              // liquidity at the beginning of the swap
                                              uint128 liquidityStart;
                                              // the timestamp of the current block
                                              uint32 blockTimestamp;
                                              // the current value of the tick accumulator, computed only if we cross an initialized tick
                                              int56 tickCumulative;
                                              // the current value of seconds per liquidity accumulator, computed only if we cross an initialized tick
                                              uint160 secondsPerLiquidityCumulativeX128;
                                              // whether we've computed and cached the above two accumulators
                                              bool computedLatestObservation;
                                          }
                                          // the top level state of the swap, the results of which are recorded in storage at the end
                                          struct SwapState {
                                              // the amount remaining to be swapped in/out of the input/output asset
                                              int256 amountSpecifiedRemaining;
                                              // the amount already swapped out/in of the output/input asset
                                              int256 amountCalculated;
                                              // current sqrt(price)
                                              uint160 sqrtPriceX96;
                                              // the tick associated with the current price
                                              int24 tick;
                                              // the global fee growth of the input token
                                              uint256 feeGrowthGlobalX128;
                                              // amount of input token paid as protocol fee
                                              uint128 protocolFee;
                                              // the current liquidity in range
                                              uint128 liquidity;
                                          }
                                          struct StepComputations {
                                              // the price at the beginning of the step
                                              uint160 sqrtPriceStartX96;
                                              // the next tick to swap to from the current tick in the swap direction
                                              int24 tickNext;
                                              // whether tickNext is initialized or not
                                              bool initialized;
                                              // sqrt(price) for the next tick (1/0)
                                              uint160 sqrtPriceNextX96;
                                              // how much is being swapped in in this step
                                              uint256 amountIn;
                                              // how much is being swapped out
                                              uint256 amountOut;
                                              // how much fee is being paid in
                                              uint256 feeAmount;
                                          }
                                          /// @inheritdoc IUniswapV3PoolActions
                                          function swap(
                                              address recipient,
                                              bool zeroForOne,
                                              int256 amountSpecified,
                                              uint160 sqrtPriceLimitX96,
                                              bytes calldata data
                                          ) external override noDelegateCall returns (int256 amount0, int256 amount1) {
                                              require(amountSpecified != 0, 'AS');
                                              Slot0 memory slot0Start = slot0;
                                              require(slot0Start.unlocked, 'LOK');
                                              require(
                                                  zeroForOne
                                                      ? sqrtPriceLimitX96 < slot0Start.sqrtPriceX96 && sqrtPriceLimitX96 > TickMath.MIN_SQRT_RATIO
                                                      : sqrtPriceLimitX96 > slot0Start.sqrtPriceX96 && sqrtPriceLimitX96 < TickMath.MAX_SQRT_RATIO,
                                                  'SPL'
                                              );
                                              slot0.unlocked = false;
                                              SwapCache memory cache =
                                                  SwapCache({
                                                      liquidityStart: liquidity,
                                                      blockTimestamp: _blockTimestamp(),
                                                      feeProtocol: zeroForOne ? (slot0Start.feeProtocol % 16) : (slot0Start.feeProtocol >> 4),
                                                      secondsPerLiquidityCumulativeX128: 0,
                                                      tickCumulative: 0,
                                                      computedLatestObservation: false
                                                  });
                                              bool exactInput = amountSpecified > 0;
                                              SwapState memory state =
                                                  SwapState({
                                                      amountSpecifiedRemaining: amountSpecified,
                                                      amountCalculated: 0,
                                                      sqrtPriceX96: slot0Start.sqrtPriceX96,
                                                      tick: slot0Start.tick,
                                                      feeGrowthGlobalX128: zeroForOne ? feeGrowthGlobal0X128 : feeGrowthGlobal1X128,
                                                      protocolFee: 0,
                                                      liquidity: cache.liquidityStart
                                                  });
                                              // continue swapping as long as we haven't used the entire input/output and haven't reached the price limit
                                              while (state.amountSpecifiedRemaining != 0 && state.sqrtPriceX96 != sqrtPriceLimitX96) {
                                                  StepComputations memory step;
                                                  step.sqrtPriceStartX96 = state.sqrtPriceX96;
                                                  (step.tickNext, step.initialized) = tickBitmap.nextInitializedTickWithinOneWord(
                                                      state.tick,
                                                      tickSpacing,
                                                      zeroForOne
                                                  );
                                                  // ensure that we do not overshoot the min/max tick, as the tick bitmap is not aware of these bounds
                                                  if (step.tickNext < TickMath.MIN_TICK) {
                                                      step.tickNext = TickMath.MIN_TICK;
                                                  } else if (step.tickNext > TickMath.MAX_TICK) {
                                                      step.tickNext = TickMath.MAX_TICK;
                                                  }
                                                  // get the price for the next tick
                                                  step.sqrtPriceNextX96 = TickMath.getSqrtRatioAtTick(step.tickNext);
                                                  // compute values to swap to the target tick, price limit, or point where input/output amount is exhausted
                                                  (state.sqrtPriceX96, step.amountIn, step.amountOut, step.feeAmount) = SwapMath.computeSwapStep(
                                                      state.sqrtPriceX96,
                                                      (zeroForOne ? step.sqrtPriceNextX96 < sqrtPriceLimitX96 : step.sqrtPriceNextX96 > sqrtPriceLimitX96)
                                                          ? sqrtPriceLimitX96
                                                          : step.sqrtPriceNextX96,
                                                      state.liquidity,
                                                      state.amountSpecifiedRemaining,
                                                      fee
                                                  );
                                                  if (exactInput) {
                                                      state.amountSpecifiedRemaining -= (step.amountIn + step.feeAmount).toInt256();
                                                      state.amountCalculated = state.amountCalculated.sub(step.amountOut.toInt256());
                                                  } else {
                                                      state.amountSpecifiedRemaining += step.amountOut.toInt256();
                                                      state.amountCalculated = state.amountCalculated.add((step.amountIn + step.feeAmount).toInt256());
                                                  }
                                                  // if the protocol fee is on, calculate how much is owed, decrement feeAmount, and increment protocolFee
                                                  if (cache.feeProtocol > 0) {
                                                      uint256 delta = step.feeAmount / cache.feeProtocol;
                                                      step.feeAmount -= delta;
                                                      state.protocolFee += uint128(delta);
                                                  }
                                                  // update global fee tracker
                                                  if (state.liquidity > 0)
                                                      state.feeGrowthGlobalX128 += FullMath.mulDiv(step.feeAmount, FixedPoint128.Q128, state.liquidity);
                                                  // shift tick if we reached the next price
                                                  if (state.sqrtPriceX96 == step.sqrtPriceNextX96) {
                                                      // if the tick is initialized, run the tick transition
                                                      if (step.initialized) {
                                                          // check for the placeholder value, which we replace with the actual value the first time the swap
                                                          // crosses an initialized tick
                                                          if (!cache.computedLatestObservation) {
                                                              (cache.tickCumulative, cache.secondsPerLiquidityCumulativeX128) = observations.observeSingle(
                                                                  cache.blockTimestamp,
                                                                  0,
                                                                  slot0Start.tick,
                                                                  slot0Start.observationIndex,
                                                                  cache.liquidityStart,
                                                                  slot0Start.observationCardinality
                                                              );
                                                              cache.computedLatestObservation = true;
                                                          }
                                                          int128 liquidityNet =
                                                              ticks.cross(
                                                                  step.tickNext,
                                                                  (zeroForOne ? state.feeGrowthGlobalX128 : feeGrowthGlobal0X128),
                                                                  (zeroForOne ? feeGrowthGlobal1X128 : state.feeGrowthGlobalX128),
                                                                  cache.secondsPerLiquidityCumulativeX128,
                                                                  cache.tickCumulative,
                                                                  cache.blockTimestamp
                                                              );
                                                          // if we're moving leftward, we interpret liquidityNet as the opposite sign
                                                          // safe because liquidityNet cannot be type(int128).min
                                                          if (zeroForOne) liquidityNet = -liquidityNet;
                                                          state.liquidity = LiquidityMath.addDelta(state.liquidity, liquidityNet);
                                                      }
                                                      state.tick = zeroForOne ? step.tickNext - 1 : step.tickNext;
                                                  } else if (state.sqrtPriceX96 != step.sqrtPriceStartX96) {
                                                      // recompute unless we're on a lower tick boundary (i.e. already transitioned ticks), and haven't moved
                                                      state.tick = TickMath.getTickAtSqrtRatio(state.sqrtPriceX96);
                                                  }
                                              }
                                              // update tick and write an oracle entry if the tick change
                                              if (state.tick != slot0Start.tick) {
                                                  (uint16 observationIndex, uint16 observationCardinality) =
                                                      observations.write(
                                                          slot0Start.observationIndex,
                                                          cache.blockTimestamp,
                                                          slot0Start.tick,
                                                          cache.liquidityStart,
                                                          slot0Start.observationCardinality,
                                                          slot0Start.observationCardinalityNext
                                                      );
                                                  (slot0.sqrtPriceX96, slot0.tick, slot0.observationIndex, slot0.observationCardinality) = (
                                                      state.sqrtPriceX96,
                                                      state.tick,
                                                      observationIndex,
                                                      observationCardinality
                                                  );
                                              } else {
                                                  // otherwise just update the price
                                                  slot0.sqrtPriceX96 = state.sqrtPriceX96;
                                              }
                                              // update liquidity if it changed
                                              if (cache.liquidityStart != state.liquidity) liquidity = state.liquidity;
                                              // update fee growth global and, if necessary, protocol fees
                                              // overflow is acceptable, protocol has to withdraw before it hits type(uint128).max fees
                                              if (zeroForOne) {
                                                  feeGrowthGlobal0X128 = state.feeGrowthGlobalX128;
                                                  if (state.protocolFee > 0) protocolFees.token0 += state.protocolFee;
                                              } else {
                                                  feeGrowthGlobal1X128 = state.feeGrowthGlobalX128;
                                                  if (state.protocolFee > 0) protocolFees.token1 += state.protocolFee;
                                              }
                                              (amount0, amount1) = zeroForOne == exactInput
                                                  ? (amountSpecified - state.amountSpecifiedRemaining, state.amountCalculated)
                                                  : (state.amountCalculated, amountSpecified - state.amountSpecifiedRemaining);
                                              // do the transfers and collect payment
                                              if (zeroForOne) {
                                                  if (amount1 < 0) TransferHelper.safeTransfer(token1, recipient, uint256(-amount1));
                                                  uint256 balance0Before = balance0();
                                                  IUniswapV3SwapCallback(msg.sender).uniswapV3SwapCallback(amount0, amount1, data);
                                                  require(balance0Before.add(uint256(amount0)) <= balance0(), 'IIA');
                                              } else {
                                                  if (amount0 < 0) TransferHelper.safeTransfer(token0, recipient, uint256(-amount0));
                                                  uint256 balance1Before = balance1();
                                                  IUniswapV3SwapCallback(msg.sender).uniswapV3SwapCallback(amount0, amount1, data);
                                                  require(balance1Before.add(uint256(amount1)) <= balance1(), 'IIA');
                                              }
                                              emit Swap(msg.sender, recipient, amount0, amount1, state.sqrtPriceX96, state.liquidity, state.tick);
                                              slot0.unlocked = true;
                                          }
                                          /// @inheritdoc IUniswapV3PoolActions
                                          function flash(
                                              address recipient,
                                              uint256 amount0,
                                              uint256 amount1,
                                              bytes calldata data
                                          ) external override lock noDelegateCall {
                                              uint128 _liquidity = liquidity;
                                              require(_liquidity > 0, 'L');
                                              uint256 fee0 = FullMath.mulDivRoundingUp(amount0, fee, 1e6);
                                              uint256 fee1 = FullMath.mulDivRoundingUp(amount1, fee, 1e6);
                                              uint256 balance0Before = balance0();
                                              uint256 balance1Before = balance1();
                                              if (amount0 > 0) TransferHelper.safeTransfer(token0, recipient, amount0);
                                              if (amount1 > 0) TransferHelper.safeTransfer(token1, recipient, amount1);
                                              IUniswapV3FlashCallback(msg.sender).uniswapV3FlashCallback(fee0, fee1, data);
                                              uint256 balance0After = balance0();
                                              uint256 balance1After = balance1();
                                              require(balance0Before.add(fee0) <= balance0After, 'F0');
                                              require(balance1Before.add(fee1) <= balance1After, 'F1');
                                              // sub is safe because we know balanceAfter is gt balanceBefore by at least fee
                                              uint256 paid0 = balance0After - balance0Before;
                                              uint256 paid1 = balance1After - balance1Before;
                                              if (paid0 > 0) {
                                                  uint8 feeProtocol0 = slot0.feeProtocol % 16;
                                                  uint256 fees0 = feeProtocol0 == 0 ? 0 : paid0 / feeProtocol0;
                                                  if (uint128(fees0) > 0) protocolFees.token0 += uint128(fees0);
                                                  feeGrowthGlobal0X128 += FullMath.mulDiv(paid0 - fees0, FixedPoint128.Q128, _liquidity);
                                              }
                                              if (paid1 > 0) {
                                                  uint8 feeProtocol1 = slot0.feeProtocol >> 4;
                                                  uint256 fees1 = feeProtocol1 == 0 ? 0 : paid1 / feeProtocol1;
                                                  if (uint128(fees1) > 0) protocolFees.token1 += uint128(fees1);
                                                  feeGrowthGlobal1X128 += FullMath.mulDiv(paid1 - fees1, FixedPoint128.Q128, _liquidity);
                                              }
                                              emit Flash(msg.sender, recipient, amount0, amount1, paid0, paid1);
                                          }
                                          /// @inheritdoc IUniswapV3PoolOwnerActions
                                          function setFeeProtocol(uint8 feeProtocol0, uint8 feeProtocol1) external override lock onlyFactoryOwner {
                                              require(
                                                  (feeProtocol0 == 0 || (feeProtocol0 >= 4 && feeProtocol0 <= 10)) &&
                                                      (feeProtocol1 == 0 || (feeProtocol1 >= 4 && feeProtocol1 <= 10))
                                              );
                                              uint8 feeProtocolOld = slot0.feeProtocol;
                                              slot0.feeProtocol = feeProtocol0 + (feeProtocol1 << 4);
                                              emit SetFeeProtocol(feeProtocolOld % 16, feeProtocolOld >> 4, feeProtocol0, feeProtocol1);
                                          }
                                          /// @inheritdoc IUniswapV3PoolOwnerActions
                                          function collectProtocol(
                                              address recipient,
                                              uint128 amount0Requested,
                                              uint128 amount1Requested
                                          ) external override lock onlyFactoryOwner returns (uint128 amount0, uint128 amount1) {
                                              amount0 = amount0Requested > protocolFees.token0 ? protocolFees.token0 : amount0Requested;
                                              amount1 = amount1Requested > protocolFees.token1 ? protocolFees.token1 : amount1Requested;
                                              if (amount0 > 0) {
                                                  if (amount0 == protocolFees.token0) amount0--; // ensure that the slot is not cleared, for gas savings
                                                  protocolFees.token0 -= amount0;
                                                  TransferHelper.safeTransfer(token0, recipient, amount0);
                                              }
                                              if (amount1 > 0) {
                                                  if (amount1 == protocolFees.token1) amount1--; // ensure that the slot is not cleared, for gas savings
                                                  protocolFees.token1 -= amount1;
                                                  TransferHelper.safeTransfer(token1, recipient, amount1);
                                              }
                                              emit CollectProtocol(msg.sender, recipient, amount0, amount1);
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      import './pool/IUniswapV3PoolImmutables.sol';
                                      import './pool/IUniswapV3PoolState.sol';
                                      import './pool/IUniswapV3PoolDerivedState.sol';
                                      import './pool/IUniswapV3PoolActions.sol';
                                      import './pool/IUniswapV3PoolOwnerActions.sol';
                                      import './pool/IUniswapV3PoolEvents.sol';
                                      /// @title The interface for a Uniswap V3 Pool
                                      /// @notice A Uniswap pool facilitates swapping and automated market making between any two assets that strictly conform
                                      /// to the ERC20 specification
                                      /// @dev The pool interface is broken up into many smaller pieces
                                      interface IUniswapV3Pool is
                                          IUniswapV3PoolImmutables,
                                          IUniswapV3PoolState,
                                          IUniswapV3PoolDerivedState,
                                          IUniswapV3PoolActions,
                                          IUniswapV3PoolOwnerActions,
                                          IUniswapV3PoolEvents
                                      {
                                      }
                                      // SPDX-License-Identifier: BUSL-1.1
                                      pragma solidity =0.7.6;
                                      /// @title Prevents delegatecall to a contract
                                      /// @notice Base contract that provides a modifier for preventing delegatecall to methods in a child contract
                                      abstract contract NoDelegateCall {
                                          /// @dev The original address of this contract
                                          address private immutable original;
                                          constructor() {
                                              // Immutables are computed in the init code of the contract, and then inlined into the deployed bytecode.
                                              // In other words, this variable won't change when it's checked at runtime.
                                              original = address(this);
                                          }
                                          /// @dev Private method is used instead of inlining into modifier because modifiers are copied into each method,
                                          ///     and the use of immutable means the address bytes are copied in every place the modifier is used.
                                          function checkNotDelegateCall() private view {
                                              require(address(this) == original);
                                          }
                                          /// @notice Prevents delegatecall into the modified method
                                          modifier noDelegateCall() {
                                              checkNotDelegateCall();
                                              _;
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.7.0;
                                      /// @title Optimized overflow and underflow safe math operations
                                      /// @notice Contains methods for doing math operations that revert on overflow or underflow for minimal gas cost
                                      library LowGasSafeMath {
                                          /// @notice Returns x + y, reverts if sum overflows uint256
                                          /// @param x The augend
                                          /// @param y The addend
                                          /// @return z The sum of x and y
                                          function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
                                              require((z = x + y) >= x);
                                          }
                                          /// @notice Returns x - y, reverts if underflows
                                          /// @param x The minuend
                                          /// @param y The subtrahend
                                          /// @return z The difference of x and y
                                          function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
                                              require((z = x - y) <= x);
                                          }
                                          /// @notice Returns x * y, reverts if overflows
                                          /// @param x The multiplicand
                                          /// @param y The multiplier
                                          /// @return z The product of x and y
                                          function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
                                              require(x == 0 || (z = x * y) / x == y);
                                          }
                                          /// @notice Returns x + y, reverts if overflows or underflows
                                          /// @param x The augend
                                          /// @param y The addend
                                          /// @return z The sum of x and y
                                          function add(int256 x, int256 y) internal pure returns (int256 z) {
                                              require((z = x + y) >= x == (y >= 0));
                                          }
                                          /// @notice Returns x - y, reverts if overflows or underflows
                                          /// @param x The minuend
                                          /// @param y The subtrahend
                                          /// @return z The difference of x and y
                                          function sub(int256 x, int256 y) internal pure returns (int256 z) {
                                              require((z = x - y) <= x == (y >= 0));
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Safe casting methods
                                      /// @notice Contains methods for safely casting between types
                                      library SafeCast {
                                          /// @notice Cast a uint256 to a uint160, revert on overflow
                                          /// @param y The uint256 to be downcasted
                                          /// @return z The downcasted integer, now type uint160
                                          function toUint160(uint256 y) internal pure returns (uint160 z) {
                                              require((z = uint160(y)) == y);
                                          }
                                          /// @notice Cast a int256 to a int128, revert on overflow or underflow
                                          /// @param y The int256 to be downcasted
                                          /// @return z The downcasted integer, now type int128
                                          function toInt128(int256 y) internal pure returns (int128 z) {
                                              require((z = int128(y)) == y);
                                          }
                                          /// @notice Cast a uint256 to a int256, revert on overflow
                                          /// @param y The uint256 to be casted
                                          /// @return z The casted integer, now type int256
                                          function toInt256(uint256 y) internal pure returns (int256 z) {
                                              require(y < 2**255);
                                              z = int256(y);
                                          }
                                      }
                                      // SPDX-License-Identifier: BUSL-1.1
                                      pragma solidity >=0.5.0;
                                      import './LowGasSafeMath.sol';
                                      import './SafeCast.sol';
                                      import './TickMath.sol';
                                      import './LiquidityMath.sol';
                                      /// @title Tick
                                      /// @notice Contains functions for managing tick processes and relevant calculations
                                      library Tick {
                                          using LowGasSafeMath for int256;
                                          using SafeCast for int256;
                                          // info stored for each initialized individual tick
                                          struct Info {
                                              // the total position liquidity that references this tick
                                              uint128 liquidityGross;
                                              // amount of net liquidity added (subtracted) when tick is crossed from left to right (right to left),
                                              int128 liquidityNet;
                                              // fee growth per unit of liquidity on the _other_ side of this tick (relative to the current tick)
                                              // only has relative meaning, not absolute — the value depends on when the tick is initialized
                                              uint256 feeGrowthOutside0X128;
                                              uint256 feeGrowthOutside1X128;
                                              // the cumulative tick value on the other side of the tick
                                              int56 tickCumulativeOutside;
                                              // the seconds per unit of liquidity on the _other_ side of this tick (relative to the current tick)
                                              // only has relative meaning, not absolute — the value depends on when the tick is initialized
                                              uint160 secondsPerLiquidityOutsideX128;
                                              // the seconds spent on the other side of the tick (relative to the current tick)
                                              // only has relative meaning, not absolute — the value depends on when the tick is initialized
                                              uint32 secondsOutside;
                                              // true iff the tick is initialized, i.e. the value is exactly equivalent to the expression liquidityGross != 0
                                              // these 8 bits are set to prevent fresh sstores when crossing newly initialized ticks
                                              bool initialized;
                                          }
                                          /// @notice Derives max liquidity per tick from given tick spacing
                                          /// @dev Executed within the pool constructor
                                          /// @param tickSpacing The amount of required tick separation, realized in multiples of `tickSpacing`
                                          ///     e.g., a tickSpacing of 3 requires ticks to be initialized every 3rd tick i.e., ..., -6, -3, 0, 3, 6, ...
                                          /// @return The max liquidity per tick
                                          function tickSpacingToMaxLiquidityPerTick(int24 tickSpacing) internal pure returns (uint128) {
                                              int24 minTick = (TickMath.MIN_TICK / tickSpacing) * tickSpacing;
                                              int24 maxTick = (TickMath.MAX_TICK / tickSpacing) * tickSpacing;
                                              uint24 numTicks = uint24((maxTick - minTick) / tickSpacing) + 1;
                                              return type(uint128).max / numTicks;
                                          }
                                          /// @notice Retrieves fee growth data
                                          /// @param self The mapping containing all tick information for initialized ticks
                                          /// @param tickLower The lower tick boundary of the position
                                          /// @param tickUpper The upper tick boundary of the position
                                          /// @param tickCurrent The current tick
                                          /// @param feeGrowthGlobal0X128 The all-time global fee growth, per unit of liquidity, in token0
                                          /// @param feeGrowthGlobal1X128 The all-time global fee growth, per unit of liquidity, in token1
                                          /// @return feeGrowthInside0X128 The all-time fee growth in token0, per unit of liquidity, inside the position's tick boundaries
                                          /// @return feeGrowthInside1X128 The all-time fee growth in token1, per unit of liquidity, inside the position's tick boundaries
                                          function getFeeGrowthInside(
                                              mapping(int24 => Tick.Info) storage self,
                                              int24 tickLower,
                                              int24 tickUpper,
                                              int24 tickCurrent,
                                              uint256 feeGrowthGlobal0X128,
                                              uint256 feeGrowthGlobal1X128
                                          ) internal view returns (uint256 feeGrowthInside0X128, uint256 feeGrowthInside1X128) {
                                              Info storage lower = self[tickLower];
                                              Info storage upper = self[tickUpper];
                                              // calculate fee growth below
                                              uint256 feeGrowthBelow0X128;
                                              uint256 feeGrowthBelow1X128;
                                              if (tickCurrent >= tickLower) {
                                                  feeGrowthBelow0X128 = lower.feeGrowthOutside0X128;
                                                  feeGrowthBelow1X128 = lower.feeGrowthOutside1X128;
                                              } else {
                                                  feeGrowthBelow0X128 = feeGrowthGlobal0X128 - lower.feeGrowthOutside0X128;
                                                  feeGrowthBelow1X128 = feeGrowthGlobal1X128 - lower.feeGrowthOutside1X128;
                                              }
                                              // calculate fee growth above
                                              uint256 feeGrowthAbove0X128;
                                              uint256 feeGrowthAbove1X128;
                                              if (tickCurrent < tickUpper) {
                                                  feeGrowthAbove0X128 = upper.feeGrowthOutside0X128;
                                                  feeGrowthAbove1X128 = upper.feeGrowthOutside1X128;
                                              } else {
                                                  feeGrowthAbove0X128 = feeGrowthGlobal0X128 - upper.feeGrowthOutside0X128;
                                                  feeGrowthAbove1X128 = feeGrowthGlobal1X128 - upper.feeGrowthOutside1X128;
                                              }
                                              feeGrowthInside0X128 = feeGrowthGlobal0X128 - feeGrowthBelow0X128 - feeGrowthAbove0X128;
                                              feeGrowthInside1X128 = feeGrowthGlobal1X128 - feeGrowthBelow1X128 - feeGrowthAbove1X128;
                                          }
                                          /// @notice Updates a tick and returns true if the tick was flipped from initialized to uninitialized, or vice versa
                                          /// @param self The mapping containing all tick information for initialized ticks
                                          /// @param tick The tick that will be updated
                                          /// @param tickCurrent The current tick
                                          /// @param liquidityDelta A new amount of liquidity to be added (subtracted) when tick is crossed from left to right (right to left)
                                          /// @param feeGrowthGlobal0X128 The all-time global fee growth, per unit of liquidity, in token0
                                          /// @param feeGrowthGlobal1X128 The all-time global fee growth, per unit of liquidity, in token1
                                          /// @param secondsPerLiquidityCumulativeX128 The all-time seconds per max(1, liquidity) of the pool
                                          /// @param time The current block timestamp cast to a uint32
                                          /// @param upper true for updating a position's upper tick, or false for updating a position's lower tick
                                          /// @param maxLiquidity The maximum liquidity allocation for a single tick
                                          /// @return flipped Whether the tick was flipped from initialized to uninitialized, or vice versa
                                          function update(
                                              mapping(int24 => Tick.Info) storage self,
                                              int24 tick,
                                              int24 tickCurrent,
                                              int128 liquidityDelta,
                                              uint256 feeGrowthGlobal0X128,
                                              uint256 feeGrowthGlobal1X128,
                                              uint160 secondsPerLiquidityCumulativeX128,
                                              int56 tickCumulative,
                                              uint32 time,
                                              bool upper,
                                              uint128 maxLiquidity
                                          ) internal returns (bool flipped) {
                                              Tick.Info storage info = self[tick];
                                              uint128 liquidityGrossBefore = info.liquidityGross;
                                              uint128 liquidityGrossAfter = LiquidityMath.addDelta(liquidityGrossBefore, liquidityDelta);
                                              require(liquidityGrossAfter <= maxLiquidity, 'LO');
                                              flipped = (liquidityGrossAfter == 0) != (liquidityGrossBefore == 0);
                                              if (liquidityGrossBefore == 0) {
                                                  // by convention, we assume that all growth before a tick was initialized happened _below_ the tick
                                                  if (tick <= tickCurrent) {
                                                      info.feeGrowthOutside0X128 = feeGrowthGlobal0X128;
                                                      info.feeGrowthOutside1X128 = feeGrowthGlobal1X128;
                                                      info.secondsPerLiquidityOutsideX128 = secondsPerLiquidityCumulativeX128;
                                                      info.tickCumulativeOutside = tickCumulative;
                                                      info.secondsOutside = time;
                                                  }
                                                  info.initialized = true;
                                              }
                                              info.liquidityGross = liquidityGrossAfter;
                                              // when the lower (upper) tick is crossed left to right (right to left), liquidity must be added (removed)
                                              info.liquidityNet = upper
                                                  ? int256(info.liquidityNet).sub(liquidityDelta).toInt128()
                                                  : int256(info.liquidityNet).add(liquidityDelta).toInt128();
                                          }
                                          /// @notice Clears tick data
                                          /// @param self The mapping containing all initialized tick information for initialized ticks
                                          /// @param tick The tick that will be cleared
                                          function clear(mapping(int24 => Tick.Info) storage self, int24 tick) internal {
                                              delete self[tick];
                                          }
                                          /// @notice Transitions to next tick as needed by price movement
                                          /// @param self The mapping containing all tick information for initialized ticks
                                          /// @param tick The destination tick of the transition
                                          /// @param feeGrowthGlobal0X128 The all-time global fee growth, per unit of liquidity, in token0
                                          /// @param feeGrowthGlobal1X128 The all-time global fee growth, per unit of liquidity, in token1
                                          /// @param secondsPerLiquidityCumulativeX128 The current seconds per liquidity
                                          /// @param time The current block.timestamp
                                          /// @return liquidityNet The amount of liquidity added (subtracted) when tick is crossed from left to right (right to left)
                                          function cross(
                                              mapping(int24 => Tick.Info) storage self,
                                              int24 tick,
                                              uint256 feeGrowthGlobal0X128,
                                              uint256 feeGrowthGlobal1X128,
                                              uint160 secondsPerLiquidityCumulativeX128,
                                              int56 tickCumulative,
                                              uint32 time
                                          ) internal returns (int128 liquidityNet) {
                                              Tick.Info storage info = self[tick];
                                              info.feeGrowthOutside0X128 = feeGrowthGlobal0X128 - info.feeGrowthOutside0X128;
                                              info.feeGrowthOutside1X128 = feeGrowthGlobal1X128 - info.feeGrowthOutside1X128;
                                              info.secondsPerLiquidityOutsideX128 = secondsPerLiquidityCumulativeX128 - info.secondsPerLiquidityOutsideX128;
                                              info.tickCumulativeOutside = tickCumulative - info.tickCumulativeOutside;
                                              info.secondsOutside = time - info.secondsOutside;
                                              liquidityNet = info.liquidityNet;
                                          }
                                      }
                                      // SPDX-License-Identifier: BUSL-1.1
                                      pragma solidity >=0.5.0;
                                      import './BitMath.sol';
                                      /// @title Packed tick initialized state library
                                      /// @notice Stores a packed mapping of tick index to its initialized state
                                      /// @dev The mapping uses int16 for keys since ticks are represented as int24 and there are 256 (2^8) values per word.
                                      library TickBitmap {
                                          /// @notice Computes the position in the mapping where the initialized bit for a tick lives
                                          /// @param tick The tick for which to compute the position
                                          /// @return wordPos The key in the mapping containing the word in which the bit is stored
                                          /// @return bitPos The bit position in the word where the flag is stored
                                          function position(int24 tick) private pure returns (int16 wordPos, uint8 bitPos) {
                                              wordPos = int16(tick >> 8);
                                              bitPos = uint8(tick % 256);
                                          }
                                          /// @notice Flips the initialized state for a given tick from false to true, or vice versa
                                          /// @param self The mapping in which to flip the tick
                                          /// @param tick The tick to flip
                                          /// @param tickSpacing The spacing between usable ticks
                                          function flipTick(
                                              mapping(int16 => uint256) storage self,
                                              int24 tick,
                                              int24 tickSpacing
                                          ) internal {
                                              require(tick % tickSpacing == 0); // ensure that the tick is spaced
                                              (int16 wordPos, uint8 bitPos) = position(tick / tickSpacing);
                                              uint256 mask = 1 << bitPos;
                                              self[wordPos] ^= mask;
                                          }
                                          /// @notice Returns the next initialized tick contained in the same word (or adjacent word) as the tick that is either
                                          /// to the left (less than or equal to) or right (greater than) of the given tick
                                          /// @param self The mapping in which to compute the next initialized tick
                                          /// @param tick The starting tick
                                          /// @param tickSpacing The spacing between usable ticks
                                          /// @param lte Whether to search for the next initialized tick to the left (less than or equal to the starting tick)
                                          /// @return next The next initialized or uninitialized tick up to 256 ticks away from the current tick
                                          /// @return initialized Whether the next tick is initialized, as the function only searches within up to 256 ticks
                                          function nextInitializedTickWithinOneWord(
                                              mapping(int16 => uint256) storage self,
                                              int24 tick,
                                              int24 tickSpacing,
                                              bool lte
                                          ) internal view returns (int24 next, bool initialized) {
                                              int24 compressed = tick / tickSpacing;
                                              if (tick < 0 && tick % tickSpacing != 0) compressed--; // round towards negative infinity
                                              if (lte) {
                                                  (int16 wordPos, uint8 bitPos) = position(compressed);
                                                  // all the 1s at or to the right of the current bitPos
                                                  uint256 mask = (1 << bitPos) - 1 + (1 << bitPos);
                                                  uint256 masked = self[wordPos] & mask;
                                                  // if there are no initialized ticks to the right of or at the current tick, return rightmost in the word
                                                  initialized = masked != 0;
                                                  // overflow/underflow is possible, but prevented externally by limiting both tickSpacing and tick
                                                  next = initialized
                                                      ? (compressed - int24(bitPos - BitMath.mostSignificantBit(masked))) * tickSpacing
                                                      : (compressed - int24(bitPos)) * tickSpacing;
                                              } else {
                                                  // start from the word of the next tick, since the current tick state doesn't matter
                                                  (int16 wordPos, uint8 bitPos) = position(compressed + 1);
                                                  // all the 1s at or to the left of the bitPos
                                                  uint256 mask = ~((1 << bitPos) - 1);
                                                  uint256 masked = self[wordPos] & mask;
                                                  // if there are no initialized ticks to the left of the current tick, return leftmost in the word
                                                  initialized = masked != 0;
                                                  // overflow/underflow is possible, but prevented externally by limiting both tickSpacing and tick
                                                  next = initialized
                                                      ? (compressed + 1 + int24(BitMath.leastSignificantBit(masked) - bitPos)) * tickSpacing
                                                      : (compressed + 1 + int24(type(uint8).max - bitPos)) * tickSpacing;
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: BUSL-1.1
                                      pragma solidity >=0.5.0;
                                      import './FullMath.sol';
                                      import './FixedPoint128.sol';
                                      import './LiquidityMath.sol';
                                      /// @title Position
                                      /// @notice Positions represent an owner address' liquidity between a lower and upper tick boundary
                                      /// @dev Positions store additional state for tracking fees owed to the position
                                      library Position {
                                          // info stored for each user's position
                                          struct Info {
                                              // the amount of liquidity owned by this position
                                              uint128 liquidity;
                                              // fee growth per unit of liquidity as of the last update to liquidity or fees owed
                                              uint256 feeGrowthInside0LastX128;
                                              uint256 feeGrowthInside1LastX128;
                                              // the fees owed to the position owner in token0/token1
                                              uint128 tokensOwed0;
                                              uint128 tokensOwed1;
                                          }
                                          /// @notice Returns the Info struct of a position, given an owner and position boundaries
                                          /// @param self The mapping containing all user positions
                                          /// @param owner The address of the position owner
                                          /// @param tickLower The lower tick boundary of the position
                                          /// @param tickUpper The upper tick boundary of the position
                                          /// @return position The position info struct of the given owners' position
                                          function get(
                                              mapping(bytes32 => Info) storage self,
                                              address owner,
                                              int24 tickLower,
                                              int24 tickUpper
                                          ) internal view returns (Position.Info storage position) {
                                              position = self[keccak256(abi.encodePacked(owner, tickLower, tickUpper))];
                                          }
                                          /// @notice Credits accumulated fees to a user's position
                                          /// @param self The individual position to update
                                          /// @param liquidityDelta The change in pool liquidity as a result of the position update
                                          /// @param feeGrowthInside0X128 The all-time fee growth in token0, per unit of liquidity, inside the position's tick boundaries
                                          /// @param feeGrowthInside1X128 The all-time fee growth in token1, per unit of liquidity, inside the position's tick boundaries
                                          function update(
                                              Info storage self,
                                              int128 liquidityDelta,
                                              uint256 feeGrowthInside0X128,
                                              uint256 feeGrowthInside1X128
                                          ) internal {
                                              Info memory _self = self;
                                              uint128 liquidityNext;
                                              if (liquidityDelta == 0) {
                                                  require(_self.liquidity > 0, 'NP'); // disallow pokes for 0 liquidity positions
                                                  liquidityNext = _self.liquidity;
                                              } else {
                                                  liquidityNext = LiquidityMath.addDelta(_self.liquidity, liquidityDelta);
                                              }
                                              // calculate accumulated fees
                                              uint128 tokensOwed0 =
                                                  uint128(
                                                      FullMath.mulDiv(
                                                          feeGrowthInside0X128 - _self.feeGrowthInside0LastX128,
                                                          _self.liquidity,
                                                          FixedPoint128.Q128
                                                      )
                                                  );
                                              uint128 tokensOwed1 =
                                                  uint128(
                                                      FullMath.mulDiv(
                                                          feeGrowthInside1X128 - _self.feeGrowthInside1LastX128,
                                                          _self.liquidity,
                                                          FixedPoint128.Q128
                                                      )
                                                  );
                                              // update the position
                                              if (liquidityDelta != 0) self.liquidity = liquidityNext;
                                              self.feeGrowthInside0LastX128 = feeGrowthInside0X128;
                                              self.feeGrowthInside1LastX128 = feeGrowthInside1X128;
                                              if (tokensOwed0 > 0 || tokensOwed1 > 0) {
                                                  // overflow is acceptable, have to withdraw before you hit type(uint128).max fees
                                                  self.tokensOwed0 += tokensOwed0;
                                                  self.tokensOwed1 += tokensOwed1;
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: BUSL-1.1
                                      pragma solidity >=0.5.0;
                                      /// @title Oracle
                                      /// @notice Provides price and liquidity data useful for a wide variety of system designs
                                      /// @dev Instances of stored oracle data, "observations", are collected in the oracle array
                                      /// Every pool is initialized with an oracle array length of 1. Anyone can pay the SSTOREs to increase the
                                      /// maximum length of the oracle array. New slots will be added when the array is fully populated.
                                      /// Observations are overwritten when the full length of the oracle array is populated.
                                      /// The most recent observation is available, independent of the length of the oracle array, by passing 0 to observe()
                                      library Oracle {
                                          struct Observation {
                                              // the block timestamp of the observation
                                              uint32 blockTimestamp;
                                              // the tick accumulator, i.e. tick * time elapsed since the pool was first initialized
                                              int56 tickCumulative;
                                              // the seconds per liquidity, i.e. seconds elapsed / max(1, liquidity) since the pool was first initialized
                                              uint160 secondsPerLiquidityCumulativeX128;
                                              // whether or not the observation is initialized
                                              bool initialized;
                                          }
                                          /// @notice Transforms a previous observation into a new observation, given the passage of time and the current tick and liquidity values
                                          /// @dev blockTimestamp _must_ be chronologically equal to or greater than last.blockTimestamp, safe for 0 or 1 overflows
                                          /// @param last The specified observation to be transformed
                                          /// @param blockTimestamp The timestamp of the new observation
                                          /// @param tick The active tick at the time of the new observation
                                          /// @param liquidity The total in-range liquidity at the time of the new observation
                                          /// @return Observation The newly populated observation
                                          function transform(
                                              Observation memory last,
                                              uint32 blockTimestamp,
                                              int24 tick,
                                              uint128 liquidity
                                          ) private pure returns (Observation memory) {
                                              uint32 delta = blockTimestamp - last.blockTimestamp;
                                              return
                                                  Observation({
                                                      blockTimestamp: blockTimestamp,
                                                      tickCumulative: last.tickCumulative + int56(tick) * delta,
                                                      secondsPerLiquidityCumulativeX128: last.secondsPerLiquidityCumulativeX128 +
                                                          ((uint160(delta) << 128) / (liquidity > 0 ? liquidity : 1)),
                                                      initialized: true
                                                  });
                                          }
                                          /// @notice Initialize the oracle array by writing the first slot. Called once for the lifecycle of the observations array
                                          /// @param self The stored oracle array
                                          /// @param time The time of the oracle initialization, via block.timestamp truncated to uint32
                                          /// @return cardinality The number of populated elements in the oracle array
                                          /// @return cardinalityNext The new length of the oracle array, independent of population
                                          function initialize(Observation[65535] storage self, uint32 time)
                                              internal
                                              returns (uint16 cardinality, uint16 cardinalityNext)
                                          {
                                              self[0] = Observation({
                                                  blockTimestamp: time,
                                                  tickCumulative: 0,
                                                  secondsPerLiquidityCumulativeX128: 0,
                                                  initialized: true
                                              });
                                              return (1, 1);
                                          }
                                          /// @notice Writes an oracle observation to the array
                                          /// @dev Writable at most once per block. Index represents the most recently written element. cardinality and index must be tracked externally.
                                          /// If the index is at the end of the allowable array length (according to cardinality), and the next cardinality
                                          /// is greater than the current one, cardinality may be increased. This restriction is created to preserve ordering.
                                          /// @param self The stored oracle array
                                          /// @param index The index of the observation that was most recently written to the observations array
                                          /// @param blockTimestamp The timestamp of the new observation
                                          /// @param tick The active tick at the time of the new observation
                                          /// @param liquidity The total in-range liquidity at the time of the new observation
                                          /// @param cardinality The number of populated elements in the oracle array
                                          /// @param cardinalityNext The new length of the oracle array, independent of population
                                          /// @return indexUpdated The new index of the most recently written element in the oracle array
                                          /// @return cardinalityUpdated The new cardinality of the oracle array
                                          function write(
                                              Observation[65535] storage self,
                                              uint16 index,
                                              uint32 blockTimestamp,
                                              int24 tick,
                                              uint128 liquidity,
                                              uint16 cardinality,
                                              uint16 cardinalityNext
                                          ) internal returns (uint16 indexUpdated, uint16 cardinalityUpdated) {
                                              Observation memory last = self[index];
                                              // early return if we've already written an observation this block
                                              if (last.blockTimestamp == blockTimestamp) return (index, cardinality);
                                              // if the conditions are right, we can bump the cardinality
                                              if (cardinalityNext > cardinality && index == (cardinality - 1)) {
                                                  cardinalityUpdated = cardinalityNext;
                                              } else {
                                                  cardinalityUpdated = cardinality;
                                              }
                                              indexUpdated = (index + 1) % cardinalityUpdated;
                                              self[indexUpdated] = transform(last, blockTimestamp, tick, liquidity);
                                          }
                                          /// @notice Prepares the oracle array to store up to `next` observations
                                          /// @param self The stored oracle array
                                          /// @param current The current next cardinality of the oracle array
                                          /// @param next The proposed next cardinality which will be populated in the oracle array
                                          /// @return next The next cardinality which will be populated in the oracle array
                                          function grow(
                                              Observation[65535] storage self,
                                              uint16 current,
                                              uint16 next
                                          ) internal returns (uint16) {
                                              require(current > 0, 'I');
                                              // no-op if the passed next value isn't greater than the current next value
                                              if (next <= current) return current;
                                              // store in each slot to prevent fresh SSTOREs in swaps
                                              // this data will not be used because the initialized boolean is still false
                                              for (uint16 i = current; i < next; i++) self[i].blockTimestamp = 1;
                                              return next;
                                          }
                                          /// @notice comparator for 32-bit timestamps
                                          /// @dev safe for 0 or 1 overflows, a and b _must_ be chronologically before or equal to time
                                          /// @param time A timestamp truncated to 32 bits
                                          /// @param a A comparison timestamp from which to determine the relative position of `time`
                                          /// @param b From which to determine the relative position of `time`
                                          /// @return bool Whether `a` is chronologically <= `b`
                                          function lte(
                                              uint32 time,
                                              uint32 a,
                                              uint32 b
                                          ) private pure returns (bool) {
                                              // if there hasn't been overflow, no need to adjust
                                              if (a <= time && b <= time) return a <= b;
                                              uint256 aAdjusted = a > time ? a : a + 2**32;
                                              uint256 bAdjusted = b > time ? b : b + 2**32;
                                              return aAdjusted <= bAdjusted;
                                          }
                                          /// @notice Fetches the observations beforeOrAt and atOrAfter a target, i.e. where [beforeOrAt, atOrAfter] is satisfied.
                                          /// The result may be the same observation, or adjacent observations.
                                          /// @dev The answer must be contained in the array, used when the target is located within the stored observation
                                          /// boundaries: older than the most recent observation and younger, or the same age as, the oldest observation
                                          /// @param self The stored oracle array
                                          /// @param time The current block.timestamp
                                          /// @param target The timestamp at which the reserved observation should be for
                                          /// @param index The index of the observation that was most recently written to the observations array
                                          /// @param cardinality The number of populated elements in the oracle array
                                          /// @return beforeOrAt The observation recorded before, or at, the target
                                          /// @return atOrAfter The observation recorded at, or after, the target
                                          function binarySearch(
                                              Observation[65535] storage self,
                                              uint32 time,
                                              uint32 target,
                                              uint16 index,
                                              uint16 cardinality
                                          ) private view returns (Observation memory beforeOrAt, Observation memory atOrAfter) {
                                              uint256 l = (index + 1) % cardinality; // oldest observation
                                              uint256 r = l + cardinality - 1; // newest observation
                                              uint256 i;
                                              while (true) {
                                                  i = (l + r) / 2;
                                                  beforeOrAt = self[i % cardinality];
                                                  // we've landed on an uninitialized tick, keep searching higher (more recently)
                                                  if (!beforeOrAt.initialized) {
                                                      l = i + 1;
                                                      continue;
                                                  }
                                                  atOrAfter = self[(i + 1) % cardinality];
                                                  bool targetAtOrAfter = lte(time, beforeOrAt.blockTimestamp, target);
                                                  // check if we've found the answer!
                                                  if (targetAtOrAfter && lte(time, target, atOrAfter.blockTimestamp)) break;
                                                  if (!targetAtOrAfter) r = i - 1;
                                                  else l = i + 1;
                                              }
                                          }
                                          /// @notice Fetches the observations beforeOrAt and atOrAfter a given target, i.e. where [beforeOrAt, atOrAfter] is satisfied
                                          /// @dev Assumes there is at least 1 initialized observation.
                                          /// Used by observeSingle() to compute the counterfactual accumulator values as of a given block timestamp.
                                          /// @param self The stored oracle array
                                          /// @param time The current block.timestamp
                                          /// @param target The timestamp at which the reserved observation should be for
                                          /// @param tick The active tick at the time of the returned or simulated observation
                                          /// @param index The index of the observation that was most recently written to the observations array
                                          /// @param liquidity The total pool liquidity at the time of the call
                                          /// @param cardinality The number of populated elements in the oracle array
                                          /// @return beforeOrAt The observation which occurred at, or before, the given timestamp
                                          /// @return atOrAfter The observation which occurred at, or after, the given timestamp
                                          function getSurroundingObservations(
                                              Observation[65535] storage self,
                                              uint32 time,
                                              uint32 target,
                                              int24 tick,
                                              uint16 index,
                                              uint128 liquidity,
                                              uint16 cardinality
                                          ) private view returns (Observation memory beforeOrAt, Observation memory atOrAfter) {
                                              // optimistically set before to the newest observation
                                              beforeOrAt = self[index];
                                              // if the target is chronologically at or after the newest observation, we can early return
                                              if (lte(time, beforeOrAt.blockTimestamp, target)) {
                                                  if (beforeOrAt.blockTimestamp == target) {
                                                      // if newest observation equals target, we're in the same block, so we can ignore atOrAfter
                                                      return (beforeOrAt, atOrAfter);
                                                  } else {
                                                      // otherwise, we need to transform
                                                      return (beforeOrAt, transform(beforeOrAt, target, tick, liquidity));
                                                  }
                                              }
                                              // now, set before to the oldest observation
                                              beforeOrAt = self[(index + 1) % cardinality];
                                              if (!beforeOrAt.initialized) beforeOrAt = self[0];
                                              // ensure that the target is chronologically at or after the oldest observation
                                              require(lte(time, beforeOrAt.blockTimestamp, target), 'OLD');
                                              // if we've reached this point, we have to binary search
                                              return binarySearch(self, time, target, index, cardinality);
                                          }
                                          /// @dev Reverts if an observation at or before the desired observation timestamp does not exist.
                                          /// 0 may be passed as `secondsAgo' to return the current cumulative values.
                                          /// If called with a timestamp falling between two observations, returns the counterfactual accumulator values
                                          /// at exactly the timestamp between the two observations.
                                          /// @param self The stored oracle array
                                          /// @param time The current block timestamp
                                          /// @param secondsAgo The amount of time to look back, in seconds, at which point to return an observation
                                          /// @param tick The current tick
                                          /// @param index The index of the observation that was most recently written to the observations array
                                          /// @param liquidity The current in-range pool liquidity
                                          /// @param cardinality The number of populated elements in the oracle array
                                          /// @return tickCumulative The tick * time elapsed since the pool was first initialized, as of `secondsAgo`
                                          /// @return secondsPerLiquidityCumulativeX128 The time elapsed / max(1, liquidity) since the pool was first initialized, as of `secondsAgo`
                                          function observeSingle(
                                              Observation[65535] storage self,
                                              uint32 time,
                                              uint32 secondsAgo,
                                              int24 tick,
                                              uint16 index,
                                              uint128 liquidity,
                                              uint16 cardinality
                                          ) internal view returns (int56 tickCumulative, uint160 secondsPerLiquidityCumulativeX128) {
                                              if (secondsAgo == 0) {
                                                  Observation memory last = self[index];
                                                  if (last.blockTimestamp != time) last = transform(last, time, tick, liquidity);
                                                  return (last.tickCumulative, last.secondsPerLiquidityCumulativeX128);
                                              }
                                              uint32 target = time - secondsAgo;
                                              (Observation memory beforeOrAt, Observation memory atOrAfter) =
                                                  getSurroundingObservations(self, time, target, tick, index, liquidity, cardinality);
                                              if (target == beforeOrAt.blockTimestamp) {
                                                  // we're at the left boundary
                                                  return (beforeOrAt.tickCumulative, beforeOrAt.secondsPerLiquidityCumulativeX128);
                                              } else if (target == atOrAfter.blockTimestamp) {
                                                  // we're at the right boundary
                                                  return (atOrAfter.tickCumulative, atOrAfter.secondsPerLiquidityCumulativeX128);
                                              } else {
                                                  // we're in the middle
                                                  uint32 observationTimeDelta = atOrAfter.blockTimestamp - beforeOrAt.blockTimestamp;
                                                  uint32 targetDelta = target - beforeOrAt.blockTimestamp;
                                                  return (
                                                      beforeOrAt.tickCumulative +
                                                          ((atOrAfter.tickCumulative - beforeOrAt.tickCumulative) / observationTimeDelta) *
                                                          targetDelta,
                                                      beforeOrAt.secondsPerLiquidityCumulativeX128 +
                                                          uint160(
                                                              (uint256(
                                                                  atOrAfter.secondsPerLiquidityCumulativeX128 - beforeOrAt.secondsPerLiquidityCumulativeX128
                                                              ) * targetDelta) / observationTimeDelta
                                                          )
                                                  );
                                              }
                                          }
                                          /// @notice Returns the accumulator values as of each time seconds ago from the given time in the array of `secondsAgos`
                                          /// @dev Reverts if `secondsAgos` > oldest observation
                                          /// @param self The stored oracle array
                                          /// @param time The current block.timestamp
                                          /// @param secondsAgos Each amount of time to look back, in seconds, at which point to return an observation
                                          /// @param tick The current tick
                                          /// @param index The index of the observation that was most recently written to the observations array
                                          /// @param liquidity The current in-range pool liquidity
                                          /// @param cardinality The number of populated elements in the oracle array
                                          /// @return tickCumulatives The tick * time elapsed since the pool was first initialized, as of each `secondsAgo`
                                          /// @return secondsPerLiquidityCumulativeX128s The cumulative seconds / max(1, liquidity) since the pool was first initialized, as of each `secondsAgo`
                                          function observe(
                                              Observation[65535] storage self,
                                              uint32 time,
                                              uint32[] memory secondsAgos,
                                              int24 tick,
                                              uint16 index,
                                              uint128 liquidity,
                                              uint16 cardinality
                                          ) internal view returns (int56[] memory tickCumulatives, uint160[] memory secondsPerLiquidityCumulativeX128s) {
                                              require(cardinality > 0, 'I');
                                              tickCumulatives = new int56[](secondsAgos.length);
                                              secondsPerLiquidityCumulativeX128s = new uint160[](secondsAgos.length);
                                              for (uint256 i = 0; i < secondsAgos.length; i++) {
                                                  (tickCumulatives[i], secondsPerLiquidityCumulativeX128s[i]) = observeSingle(
                                                      self,
                                                      time,
                                                      secondsAgos[i],
                                                      tick,
                                                      index,
                                                      liquidity,
                                                      cardinality
                                                  );
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity >=0.4.0;
                                      /// @title Contains 512-bit math functions
                                      /// @notice Facilitates multiplication and division that can have overflow of an intermediate value without any loss of precision
                                      /// @dev Handles "phantom overflow" i.e., allows multiplication and division where an intermediate value overflows 256 bits
                                      library FullMath {
                                          /// @notice Calculates floor(a×b÷denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
                                          /// @param a The multiplicand
                                          /// @param b The multiplier
                                          /// @param denominator The divisor
                                          /// @return result The 256-bit result
                                          /// @dev Credit to Remco Bloemen under MIT license https://xn--2-umb.com/21/muldiv
                                          function mulDiv(
                                              uint256 a,
                                              uint256 b,
                                              uint256 denominator
                                          ) internal pure returns (uint256 result) {
                                              // 512-bit multiply [prod1 prod0] = a * b
                                              // Compute the product mod 2**256 and mod 2**256 - 1
                                              // then use the Chinese Remainder Theorem to reconstruct
                                              // the 512 bit result. The result is stored in two 256
                                              // variables such that product = prod1 * 2**256 + prod0
                                              uint256 prod0; // Least significant 256 bits of the product
                                              uint256 prod1; // Most significant 256 bits of the product
                                              assembly {
                                                  let mm := mulmod(a, b, not(0))
                                                  prod0 := mul(a, b)
                                                  prod1 := sub(sub(mm, prod0), lt(mm, prod0))
                                              }
                                              // Handle non-overflow cases, 256 by 256 division
                                              if (prod1 == 0) {
                                                  require(denominator > 0);
                                                  assembly {
                                                      result := div(prod0, denominator)
                                                  }
                                                  return result;
                                              }
                                              // Make sure the result is less than 2**256.
                                              // Also prevents denominator == 0
                                              require(denominator > prod1);
                                              ///////////////////////////////////////////////
                                              // 512 by 256 division.
                                              ///////////////////////////////////////////////
                                              // Make division exact by subtracting the remainder from [prod1 prod0]
                                              // Compute remainder using mulmod
                                              uint256 remainder;
                                              assembly {
                                                  remainder := mulmod(a, b, denominator)
                                              }
                                              // Subtract 256 bit number from 512 bit number
                                              assembly {
                                                  prod1 := sub(prod1, gt(remainder, prod0))
                                                  prod0 := sub(prod0, remainder)
                                              }
                                              // Factor powers of two out of denominator
                                              // Compute largest power of two divisor of denominator.
                                              // Always >= 1.
                                              uint256 twos = -denominator & denominator;
                                              // Divide denominator by power of two
                                              assembly {
                                                  denominator := div(denominator, twos)
                                              }
                                              // Divide [prod1 prod0] by the factors of two
                                              assembly {
                                                  prod0 := div(prod0, twos)
                                              }
                                              // Shift in bits from prod1 into prod0. For this we need
                                              // to flip `twos` such that it is 2**256 / twos.
                                              // If twos is zero, then it becomes one
                                              assembly {
                                                  twos := add(div(sub(0, twos), twos), 1)
                                              }
                                              prod0 |= prod1 * twos;
                                              // Invert denominator mod 2**256
                                              // Now that denominator is an odd number, it has an inverse
                                              // modulo 2**256 such that denominator * inv = 1 mod 2**256.
                                              // Compute the inverse by starting with a seed that is correct
                                              // correct for four bits. That is, denominator * inv = 1 mod 2**4
                                              uint256 inv = (3 * denominator) ^ 2;
                                              // Now use Newton-Raphson iteration to improve the precision.
                                              // Thanks to Hensel's lifting lemma, this also works in modular
                                              // arithmetic, doubling the correct bits in each step.
                                              inv *= 2 - denominator * inv; // inverse mod 2**8
                                              inv *= 2 - denominator * inv; // inverse mod 2**16
                                              inv *= 2 - denominator * inv; // inverse mod 2**32
                                              inv *= 2 - denominator * inv; // inverse mod 2**64
                                              inv *= 2 - denominator * inv; // inverse mod 2**128
                                              inv *= 2 - denominator * inv; // inverse mod 2**256
                                              // Because the division is now exact we can divide by multiplying
                                              // with the modular inverse of denominator. This will give us the
                                              // correct result modulo 2**256. Since the precoditions guarantee
                                              // that the outcome is less than 2**256, this is the final result.
                                              // We don't need to compute the high bits of the result and prod1
                                              // is no longer required.
                                              result = prod0 * inv;
                                              return result;
                                          }
                                          /// @notice Calculates ceil(a×b÷denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
                                          /// @param a The multiplicand
                                          /// @param b The multiplier
                                          /// @param denominator The divisor
                                          /// @return result The 256-bit result
                                          function mulDivRoundingUp(
                                              uint256 a,
                                              uint256 b,
                                              uint256 denominator
                                          ) internal pure returns (uint256 result) {
                                              result = mulDiv(a, b, denominator);
                                              if (mulmod(a, b, denominator) > 0) {
                                                  require(result < type(uint256).max);
                                                  result++;
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.4.0;
                                      /// @title FixedPoint128
                                      /// @notice A library for handling binary fixed point numbers, see https://en.wikipedia.org/wiki/Q_(number_format)
                                      library FixedPoint128 {
                                          uint256 internal constant Q128 = 0x100000000000000000000000000000000;
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.6.0;
                                      import '../interfaces/IERC20Minimal.sol';
                                      /// @title TransferHelper
                                      /// @notice Contains helper methods for interacting with ERC20 tokens that do not consistently return true/false
                                      library TransferHelper {
                                          /// @notice Transfers tokens from msg.sender to a recipient
                                          /// @dev Calls transfer on token contract, errors with TF if transfer fails
                                          /// @param token The contract address of the token which will be transferred
                                          /// @param to The recipient of the transfer
                                          /// @param value The value of the transfer
                                          function safeTransfer(
                                              address token,
                                              address to,
                                              uint256 value
                                          ) internal {
                                              (bool success, bytes memory data) =
                                                  token.call(abi.encodeWithSelector(IERC20Minimal.transfer.selector, to, value));
                                              require(success && (data.length == 0 || abi.decode(data, (bool))), 'TF');
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Math library for computing sqrt prices from ticks and vice versa
                                      /// @notice Computes sqrt price for ticks of size 1.0001, i.e. sqrt(1.0001^tick) as fixed point Q64.96 numbers. Supports
                                      /// prices between 2**-128 and 2**128
                                      library TickMath {
                                          /// @dev The minimum tick that may be passed to #getSqrtRatioAtTick computed from log base 1.0001 of 2**-128
                                          int24 internal constant MIN_TICK = -887272;
                                          /// @dev The maximum tick that may be passed to #getSqrtRatioAtTick computed from log base 1.0001 of 2**128
                                          int24 internal constant MAX_TICK = -MIN_TICK;
                                          /// @dev The minimum value that can be returned from #getSqrtRatioAtTick. Equivalent to getSqrtRatioAtTick(MIN_TICK)
                                          uint160 internal constant MIN_SQRT_RATIO = 4295128739;
                                          /// @dev The maximum value that can be returned from #getSqrtRatioAtTick. Equivalent to getSqrtRatioAtTick(MAX_TICK)
                                          uint160 internal constant MAX_SQRT_RATIO = 1461446703485210103287273052203988822378723970342;
                                          /// @notice Calculates sqrt(1.0001^tick) * 2^96
                                          /// @dev Throws if |tick| > max tick
                                          /// @param tick The input tick for the above formula
                                          /// @return sqrtPriceX96 A Fixed point Q64.96 number representing the sqrt of the ratio of the two assets (token1/token0)
                                          /// at the given tick
                                          function getSqrtRatioAtTick(int24 tick) internal pure returns (uint160 sqrtPriceX96) {
                                              uint256 absTick = tick < 0 ? uint256(-int256(tick)) : uint256(int256(tick));
                                              require(absTick <= uint256(MAX_TICK), 'T');
                                              uint256 ratio = absTick & 0x1 != 0 ? 0xfffcb933bd6fad37aa2d162d1a594001 : 0x100000000000000000000000000000000;
                                              if (absTick & 0x2 != 0) ratio = (ratio * 0xfff97272373d413259a46990580e213a) >> 128;
                                              if (absTick & 0x4 != 0) ratio = (ratio * 0xfff2e50f5f656932ef12357cf3c7fdcc) >> 128;
                                              if (absTick & 0x8 != 0) ratio = (ratio * 0xffe5caca7e10e4e61c3624eaa0941cd0) >> 128;
                                              if (absTick & 0x10 != 0) ratio = (ratio * 0xffcb9843d60f6159c9db58835c926644) >> 128;
                                              if (absTick & 0x20 != 0) ratio = (ratio * 0xff973b41fa98c081472e6896dfb254c0) >> 128;
                                              if (absTick & 0x40 != 0) ratio = (ratio * 0xff2ea16466c96a3843ec78b326b52861) >> 128;
                                              if (absTick & 0x80 != 0) ratio = (ratio * 0xfe5dee046a99a2a811c461f1969c3053) >> 128;
                                              if (absTick & 0x100 != 0) ratio = (ratio * 0xfcbe86c7900a88aedcffc83b479aa3a4) >> 128;
                                              if (absTick & 0x200 != 0) ratio = (ratio * 0xf987a7253ac413176f2b074cf7815e54) >> 128;
                                              if (absTick & 0x400 != 0) ratio = (ratio * 0xf3392b0822b70005940c7a398e4b70f3) >> 128;
                                              if (absTick & 0x800 != 0) ratio = (ratio * 0xe7159475a2c29b7443b29c7fa6e889d9) >> 128;
                                              if (absTick & 0x1000 != 0) ratio = (ratio * 0xd097f3bdfd2022b8845ad8f792aa5825) >> 128;
                                              if (absTick & 0x2000 != 0) ratio = (ratio * 0xa9f746462d870fdf8a65dc1f90e061e5) >> 128;
                                              if (absTick & 0x4000 != 0) ratio = (ratio * 0x70d869a156d2a1b890bb3df62baf32f7) >> 128;
                                              if (absTick & 0x8000 != 0) ratio = (ratio * 0x31be135f97d08fd981231505542fcfa6) >> 128;
                                              if (absTick & 0x10000 != 0) ratio = (ratio * 0x9aa508b5b7a84e1c677de54f3e99bc9) >> 128;
                                              if (absTick & 0x20000 != 0) ratio = (ratio * 0x5d6af8dedb81196699c329225ee604) >> 128;
                                              if (absTick & 0x40000 != 0) ratio = (ratio * 0x2216e584f5fa1ea926041bedfe98) >> 128;
                                              if (absTick & 0x80000 != 0) ratio = (ratio * 0x48a170391f7dc42444e8fa2) >> 128;
                                              if (tick > 0) ratio = type(uint256).max / ratio;
                                              // this divides by 1<<32 rounding up to go from a Q128.128 to a Q128.96.
                                              // we then downcast because we know the result always fits within 160 bits due to our tick input constraint
                                              // we round up in the division so getTickAtSqrtRatio of the output price is always consistent
                                              sqrtPriceX96 = uint160((ratio >> 32) + (ratio % (1 << 32) == 0 ? 0 : 1));
                                          }
                                          /// @notice Calculates the greatest tick value such that getRatioAtTick(tick) <= ratio
                                          /// @dev Throws in case sqrtPriceX96 < MIN_SQRT_RATIO, as MIN_SQRT_RATIO is the lowest value getRatioAtTick may
                                          /// ever return.
                                          /// @param sqrtPriceX96 The sqrt ratio for which to compute the tick as a Q64.96
                                          /// @return tick The greatest tick for which the ratio is less than or equal to the input ratio
                                          function getTickAtSqrtRatio(uint160 sqrtPriceX96) internal pure returns (int24 tick) {
                                              // second inequality must be < because the price can never reach the price at the max tick
                                              require(sqrtPriceX96 >= MIN_SQRT_RATIO && sqrtPriceX96 < MAX_SQRT_RATIO, 'R');
                                              uint256 ratio = uint256(sqrtPriceX96) << 32;
                                              uint256 r = ratio;
                                              uint256 msb = 0;
                                              assembly {
                                                  let f := shl(7, gt(r, 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF))
                                                  msb := or(msb, f)
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  let f := shl(6, gt(r, 0xFFFFFFFFFFFFFFFF))
                                                  msb := or(msb, f)
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  let f := shl(5, gt(r, 0xFFFFFFFF))
                                                  msb := or(msb, f)
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  let f := shl(4, gt(r, 0xFFFF))
                                                  msb := or(msb, f)
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  let f := shl(3, gt(r, 0xFF))
                                                  msb := or(msb, f)
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  let f := shl(2, gt(r, 0xF))
                                                  msb := or(msb, f)
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  let f := shl(1, gt(r, 0x3))
                                                  msb := or(msb, f)
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  let f := gt(r, 0x1)
                                                  msb := or(msb, f)
                                              }
                                              if (msb >= 128) r = ratio >> (msb - 127);
                                              else r = ratio << (127 - msb);
                                              int256 log_2 = (int256(msb) - 128) << 64;
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(63, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(62, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(61, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(60, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(59, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(58, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(57, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(56, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(55, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(54, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(53, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(52, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(51, f))
                                                  r := shr(f, r)
                                              }
                                              assembly {
                                                  r := shr(127, mul(r, r))
                                                  let f := shr(128, r)
                                                  log_2 := or(log_2, shl(50, f))
                                              }
                                              int256 log_sqrt10001 = log_2 * 255738958999603826347141; // 128.128 number
                                              int24 tickLow = int24((log_sqrt10001 - 3402992956809132418596140100660247210) >> 128);
                                              int24 tickHi = int24((log_sqrt10001 + 291339464771989622907027621153398088495) >> 128);
                                              tick = tickLow == tickHi ? tickLow : getSqrtRatioAtTick(tickHi) <= sqrtPriceX96 ? tickHi : tickLow;
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Math library for liquidity
                                      library LiquidityMath {
                                          /// @notice Add a signed liquidity delta to liquidity and revert if it overflows or underflows
                                          /// @param x The liquidity before change
                                          /// @param y The delta by which liquidity should be changed
                                          /// @return z The liquidity delta
                                          function addDelta(uint128 x, int128 y) internal pure returns (uint128 z) {
                                              if (y < 0) {
                                                  require((z = x - uint128(-y)) < x, 'LS');
                                              } else {
                                                  require((z = x + uint128(y)) >= x, 'LA');
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: BUSL-1.1
                                      pragma solidity >=0.5.0;
                                      import './LowGasSafeMath.sol';
                                      import './SafeCast.sol';
                                      import './FullMath.sol';
                                      import './UnsafeMath.sol';
                                      import './FixedPoint96.sol';
                                      /// @title Functions based on Q64.96 sqrt price and liquidity
                                      /// @notice Contains the math that uses square root of price as a Q64.96 and liquidity to compute deltas
                                      library SqrtPriceMath {
                                          using LowGasSafeMath for uint256;
                                          using SafeCast for uint256;
                                          /// @notice Gets the next sqrt price given a delta of token0
                                          /// @dev Always rounds up, because in the exact output case (increasing price) we need to move the price at least
                                          /// far enough to get the desired output amount, and in the exact input case (decreasing price) we need to move the
                                          /// price less in order to not send too much output.
                                          /// The most precise formula for this is liquidity * sqrtPX96 / (liquidity +- amount * sqrtPX96),
                                          /// if this is impossible because of overflow, we calculate liquidity / (liquidity / sqrtPX96 +- amount).
                                          /// @param sqrtPX96 The starting price, i.e. before accounting for the token0 delta
                                          /// @param liquidity The amount of usable liquidity
                                          /// @param amount How much of token0 to add or remove from virtual reserves
                                          /// @param add Whether to add or remove the amount of token0
                                          /// @return The price after adding or removing amount, depending on add
                                          function getNextSqrtPriceFromAmount0RoundingUp(
                                              uint160 sqrtPX96,
                                              uint128 liquidity,
                                              uint256 amount,
                                              bool add
                                          ) internal pure returns (uint160) {
                                              // we short circuit amount == 0 because the result is otherwise not guaranteed to equal the input price
                                              if (amount == 0) return sqrtPX96;
                                              uint256 numerator1 = uint256(liquidity) << FixedPoint96.RESOLUTION;
                                              if (add) {
                                                  uint256 product;
                                                  if ((product = amount * sqrtPX96) / amount == sqrtPX96) {
                                                      uint256 denominator = numerator1 + product;
                                                      if (denominator >= numerator1)
                                                          // always fits in 160 bits
                                                          return uint160(FullMath.mulDivRoundingUp(numerator1, sqrtPX96, denominator));
                                                  }
                                                  return uint160(UnsafeMath.divRoundingUp(numerator1, (numerator1 / sqrtPX96).add(amount)));
                                              } else {
                                                  uint256 product;
                                                  // if the product overflows, we know the denominator underflows
                                                  // in addition, we must check that the denominator does not underflow
                                                  require((product = amount * sqrtPX96) / amount == sqrtPX96 && numerator1 > product);
                                                  uint256 denominator = numerator1 - product;
                                                  return FullMath.mulDivRoundingUp(numerator1, sqrtPX96, denominator).toUint160();
                                              }
                                          }
                                          /// @notice Gets the next sqrt price given a delta of token1
                                          /// @dev Always rounds down, because in the exact output case (decreasing price) we need to move the price at least
                                          /// far enough to get the desired output amount, and in the exact input case (increasing price) we need to move the
                                          /// price less in order to not send too much output.
                                          /// The formula we compute is within <1 wei of the lossless version: sqrtPX96 +- amount / liquidity
                                          /// @param sqrtPX96 The starting price, i.e., before accounting for the token1 delta
                                          /// @param liquidity The amount of usable liquidity
                                          /// @param amount How much of token1 to add, or remove, from virtual reserves
                                          /// @param add Whether to add, or remove, the amount of token1
                                          /// @return The price after adding or removing `amount`
                                          function getNextSqrtPriceFromAmount1RoundingDown(
                                              uint160 sqrtPX96,
                                              uint128 liquidity,
                                              uint256 amount,
                                              bool add
                                          ) internal pure returns (uint160) {
                                              // if we're adding (subtracting), rounding down requires rounding the quotient down (up)
                                              // in both cases, avoid a mulDiv for most inputs
                                              if (add) {
                                                  uint256 quotient =
                                                      (
                                                          amount <= type(uint160).max
                                                              ? (amount << FixedPoint96.RESOLUTION) / liquidity
                                                              : FullMath.mulDiv(amount, FixedPoint96.Q96, liquidity)
                                                      );
                                                  return uint256(sqrtPX96).add(quotient).toUint160();
                                              } else {
                                                  uint256 quotient =
                                                      (
                                                          amount <= type(uint160).max
                                                              ? UnsafeMath.divRoundingUp(amount << FixedPoint96.RESOLUTION, liquidity)
                                                              : FullMath.mulDivRoundingUp(amount, FixedPoint96.Q96, liquidity)
                                                      );
                                                  require(sqrtPX96 > quotient);
                                                  // always fits 160 bits
                                                  return uint160(sqrtPX96 - quotient);
                                              }
                                          }
                                          /// @notice Gets the next sqrt price given an input amount of token0 or token1
                                          /// @dev Throws if price or liquidity are 0, or if the next price is out of bounds
                                          /// @param sqrtPX96 The starting price, i.e., before accounting for the input amount
                                          /// @param liquidity The amount of usable liquidity
                                          /// @param amountIn How much of token0, or token1, is being swapped in
                                          /// @param zeroForOne Whether the amount in is token0 or token1
                                          /// @return sqrtQX96 The price after adding the input amount to token0 or token1
                                          function getNextSqrtPriceFromInput(
                                              uint160 sqrtPX96,
                                              uint128 liquidity,
                                              uint256 amountIn,
                                              bool zeroForOne
                                          ) internal pure returns (uint160 sqrtQX96) {
                                              require(sqrtPX96 > 0);
                                              require(liquidity > 0);
                                              // round to make sure that we don't pass the target price
                                              return
                                                  zeroForOne
                                                      ? getNextSqrtPriceFromAmount0RoundingUp(sqrtPX96, liquidity, amountIn, true)
                                                      : getNextSqrtPriceFromAmount1RoundingDown(sqrtPX96, liquidity, amountIn, true);
                                          }
                                          /// @notice Gets the next sqrt price given an output amount of token0 or token1
                                          /// @dev Throws if price or liquidity are 0 or the next price is out of bounds
                                          /// @param sqrtPX96 The starting price before accounting for the output amount
                                          /// @param liquidity The amount of usable liquidity
                                          /// @param amountOut How much of token0, or token1, is being swapped out
                                          /// @param zeroForOne Whether the amount out is token0 or token1
                                          /// @return sqrtQX96 The price after removing the output amount of token0 or token1
                                          function getNextSqrtPriceFromOutput(
                                              uint160 sqrtPX96,
                                              uint128 liquidity,
                                              uint256 amountOut,
                                              bool zeroForOne
                                          ) internal pure returns (uint160 sqrtQX96) {
                                              require(sqrtPX96 > 0);
                                              require(liquidity > 0);
                                              // round to make sure that we pass the target price
                                              return
                                                  zeroForOne
                                                      ? getNextSqrtPriceFromAmount1RoundingDown(sqrtPX96, liquidity, amountOut, false)
                                                      : getNextSqrtPriceFromAmount0RoundingUp(sqrtPX96, liquidity, amountOut, false);
                                          }
                                          /// @notice Gets the amount0 delta between two prices
                                          /// @dev Calculates liquidity / sqrt(lower) - liquidity / sqrt(upper),
                                          /// i.e. liquidity * (sqrt(upper) - sqrt(lower)) / (sqrt(upper) * sqrt(lower))
                                          /// @param sqrtRatioAX96 A sqrt price
                                          /// @param sqrtRatioBX96 Another sqrt price
                                          /// @param liquidity The amount of usable liquidity
                                          /// @param roundUp Whether to round the amount up or down
                                          /// @return amount0 Amount of token0 required to cover a position of size liquidity between the two passed prices
                                          function getAmount0Delta(
                                              uint160 sqrtRatioAX96,
                                              uint160 sqrtRatioBX96,
                                              uint128 liquidity,
                                              bool roundUp
                                          ) internal pure returns (uint256 amount0) {
                                              if (sqrtRatioAX96 > sqrtRatioBX96) (sqrtRatioAX96, sqrtRatioBX96) = (sqrtRatioBX96, sqrtRatioAX96);
                                              uint256 numerator1 = uint256(liquidity) << FixedPoint96.RESOLUTION;
                                              uint256 numerator2 = sqrtRatioBX96 - sqrtRatioAX96;
                                              require(sqrtRatioAX96 > 0);
                                              return
                                                  roundUp
                                                      ? UnsafeMath.divRoundingUp(
                                                          FullMath.mulDivRoundingUp(numerator1, numerator2, sqrtRatioBX96),
                                                          sqrtRatioAX96
                                                      )
                                                      : FullMath.mulDiv(numerator1, numerator2, sqrtRatioBX96) / sqrtRatioAX96;
                                          }
                                          /// @notice Gets the amount1 delta between two prices
                                          /// @dev Calculates liquidity * (sqrt(upper) - sqrt(lower))
                                          /// @param sqrtRatioAX96 A sqrt price
                                          /// @param sqrtRatioBX96 Another sqrt price
                                          /// @param liquidity The amount of usable liquidity
                                          /// @param roundUp Whether to round the amount up, or down
                                          /// @return amount1 Amount of token1 required to cover a position of size liquidity between the two passed prices
                                          function getAmount1Delta(
                                              uint160 sqrtRatioAX96,
                                              uint160 sqrtRatioBX96,
                                              uint128 liquidity,
                                              bool roundUp
                                          ) internal pure returns (uint256 amount1) {
                                              if (sqrtRatioAX96 > sqrtRatioBX96) (sqrtRatioAX96, sqrtRatioBX96) = (sqrtRatioBX96, sqrtRatioAX96);
                                              return
                                                  roundUp
                                                      ? FullMath.mulDivRoundingUp(liquidity, sqrtRatioBX96 - sqrtRatioAX96, FixedPoint96.Q96)
                                                      : FullMath.mulDiv(liquidity, sqrtRatioBX96 - sqrtRatioAX96, FixedPoint96.Q96);
                                          }
                                          /// @notice Helper that gets signed token0 delta
                                          /// @param sqrtRatioAX96 A sqrt price
                                          /// @param sqrtRatioBX96 Another sqrt price
                                          /// @param liquidity The change in liquidity for which to compute the amount0 delta
                                          /// @return amount0 Amount of token0 corresponding to the passed liquidityDelta between the two prices
                                          function getAmount0Delta(
                                              uint160 sqrtRatioAX96,
                                              uint160 sqrtRatioBX96,
                                              int128 liquidity
                                          ) internal pure returns (int256 amount0) {
                                              return
                                                  liquidity < 0
                                                      ? -getAmount0Delta(sqrtRatioAX96, sqrtRatioBX96, uint128(-liquidity), false).toInt256()
                                                      : getAmount0Delta(sqrtRatioAX96, sqrtRatioBX96, uint128(liquidity), true).toInt256();
                                          }
                                          /// @notice Helper that gets signed token1 delta
                                          /// @param sqrtRatioAX96 A sqrt price
                                          /// @param sqrtRatioBX96 Another sqrt price
                                          /// @param liquidity The change in liquidity for which to compute the amount1 delta
                                          /// @return amount1 Amount of token1 corresponding to the passed liquidityDelta between the two prices
                                          function getAmount1Delta(
                                              uint160 sqrtRatioAX96,
                                              uint160 sqrtRatioBX96,
                                              int128 liquidity
                                          ) internal pure returns (int256 amount1) {
                                              return
                                                  liquidity < 0
                                                      ? -getAmount1Delta(sqrtRatioAX96, sqrtRatioBX96, uint128(-liquidity), false).toInt256()
                                                      : getAmount1Delta(sqrtRatioAX96, sqrtRatioBX96, uint128(liquidity), true).toInt256();
                                          }
                                      }
                                      // SPDX-License-Identifier: BUSL-1.1
                                      pragma solidity >=0.5.0;
                                      import './FullMath.sol';
                                      import './SqrtPriceMath.sol';
                                      /// @title Computes the result of a swap within ticks
                                      /// @notice Contains methods for computing the result of a swap within a single tick price range, i.e., a single tick.
                                      library SwapMath {
                                          /// @notice Computes the result of swapping some amount in, or amount out, given the parameters of the swap
                                          /// @dev The fee, plus the amount in, will never exceed the amount remaining if the swap's `amountSpecified` is positive
                                          /// @param sqrtRatioCurrentX96 The current sqrt price of the pool
                                          /// @param sqrtRatioTargetX96 The price that cannot be exceeded, from which the direction of the swap is inferred
                                          /// @param liquidity The usable liquidity
                                          /// @param amountRemaining How much input or output amount is remaining to be swapped in/out
                                          /// @param feePips The fee taken from the input amount, expressed in hundredths of a bip
                                          /// @return sqrtRatioNextX96 The price after swapping the amount in/out, not to exceed the price target
                                          /// @return amountIn The amount to be swapped in, of either token0 or token1, based on the direction of the swap
                                          /// @return amountOut The amount to be received, of either token0 or token1, based on the direction of the swap
                                          /// @return feeAmount The amount of input that will be taken as a fee
                                          function computeSwapStep(
                                              uint160 sqrtRatioCurrentX96,
                                              uint160 sqrtRatioTargetX96,
                                              uint128 liquidity,
                                              int256 amountRemaining,
                                              uint24 feePips
                                          )
                                              internal
                                              pure
                                              returns (
                                                  uint160 sqrtRatioNextX96,
                                                  uint256 amountIn,
                                                  uint256 amountOut,
                                                  uint256 feeAmount
                                              )
                                          {
                                              bool zeroForOne = sqrtRatioCurrentX96 >= sqrtRatioTargetX96;
                                              bool exactIn = amountRemaining >= 0;
                                              if (exactIn) {
                                                  uint256 amountRemainingLessFee = FullMath.mulDiv(uint256(amountRemaining), 1e6 - feePips, 1e6);
                                                  amountIn = zeroForOne
                                                      ? SqrtPriceMath.getAmount0Delta(sqrtRatioTargetX96, sqrtRatioCurrentX96, liquidity, true)
                                                      : SqrtPriceMath.getAmount1Delta(sqrtRatioCurrentX96, sqrtRatioTargetX96, liquidity, true);
                                                  if (amountRemainingLessFee >= amountIn) sqrtRatioNextX96 = sqrtRatioTargetX96;
                                                  else
                                                      sqrtRatioNextX96 = SqrtPriceMath.getNextSqrtPriceFromInput(
                                                          sqrtRatioCurrentX96,
                                                          liquidity,
                                                          amountRemainingLessFee,
                                                          zeroForOne
                                                      );
                                              } else {
                                                  amountOut = zeroForOne
                                                      ? SqrtPriceMath.getAmount1Delta(sqrtRatioTargetX96, sqrtRatioCurrentX96, liquidity, false)
                                                      : SqrtPriceMath.getAmount0Delta(sqrtRatioCurrentX96, sqrtRatioTargetX96, liquidity, false);
                                                  if (uint256(-amountRemaining) >= amountOut) sqrtRatioNextX96 = sqrtRatioTargetX96;
                                                  else
                                                      sqrtRatioNextX96 = SqrtPriceMath.getNextSqrtPriceFromOutput(
                                                          sqrtRatioCurrentX96,
                                                          liquidity,
                                                          uint256(-amountRemaining),
                                                          zeroForOne
                                                      );
                                              }
                                              bool max = sqrtRatioTargetX96 == sqrtRatioNextX96;
                                              // get the input/output amounts
                                              if (zeroForOne) {
                                                  amountIn = max && exactIn
                                                      ? amountIn
                                                      : SqrtPriceMath.getAmount0Delta(sqrtRatioNextX96, sqrtRatioCurrentX96, liquidity, true);
                                                  amountOut = max && !exactIn
                                                      ? amountOut
                                                      : SqrtPriceMath.getAmount1Delta(sqrtRatioNextX96, sqrtRatioCurrentX96, liquidity, false);
                                              } else {
                                                  amountIn = max && exactIn
                                                      ? amountIn
                                                      : SqrtPriceMath.getAmount1Delta(sqrtRatioCurrentX96, sqrtRatioNextX96, liquidity, true);
                                                  amountOut = max && !exactIn
                                                      ? amountOut
                                                      : SqrtPriceMath.getAmount0Delta(sqrtRatioCurrentX96, sqrtRatioNextX96, liquidity, false);
                                              }
                                              // cap the output amount to not exceed the remaining output amount
                                              if (!exactIn && amountOut > uint256(-amountRemaining)) {
                                                  amountOut = uint256(-amountRemaining);
                                              }
                                              if (exactIn && sqrtRatioNextX96 != sqrtRatioTargetX96) {
                                                  // we didn't reach the target, so take the remainder of the maximum input as fee
                                                  feeAmount = uint256(amountRemaining) - amountIn;
                                              } else {
                                                  feeAmount = FullMath.mulDivRoundingUp(amountIn, feePips, 1e6 - feePips);
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title An interface for a contract that is capable of deploying Uniswap V3 Pools
                                      /// @notice A contract that constructs a pool must implement this to pass arguments to the pool
                                      /// @dev This is used to avoid having constructor arguments in the pool contract, which results in the init code hash
                                      /// of the pool being constant allowing the CREATE2 address of the pool to be cheaply computed on-chain
                                      interface IUniswapV3PoolDeployer {
                                          /// @notice Get the parameters to be used in constructing the pool, set transiently during pool creation.
                                          /// @dev Called by the pool constructor to fetch the parameters of the pool
                                          /// Returns factory The factory address
                                          /// Returns token0 The first token of the pool by address sort order
                                          /// Returns token1 The second token of the pool by address sort order
                                          /// Returns fee The fee collected upon every swap in the pool, denominated in hundredths of a bip
                                          /// Returns tickSpacing The minimum number of ticks between initialized ticks
                                          function parameters()
                                              external
                                              view
                                              returns (
                                                  address factory,
                                                  address token0,
                                                  address token1,
                                                  uint24 fee,
                                                  int24 tickSpacing
                                              );
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title The interface for the Uniswap V3 Factory
                                      /// @notice The Uniswap V3 Factory facilitates creation of Uniswap V3 pools and control over the protocol fees
                                      interface IUniswapV3Factory {
                                          /// @notice Emitted when the owner of the factory is changed
                                          /// @param oldOwner The owner before the owner was changed
                                          /// @param newOwner The owner after the owner was changed
                                          event OwnerChanged(address indexed oldOwner, address indexed newOwner);
                                          /// @notice Emitted when a pool is created
                                          /// @param token0 The first token of the pool by address sort order
                                          /// @param token1 The second token of the pool by address sort order
                                          /// @param fee The fee collected upon every swap in the pool, denominated in hundredths of a bip
                                          /// @param tickSpacing The minimum number of ticks between initialized ticks
                                          /// @param pool The address of the created pool
                                          event PoolCreated(
                                              address indexed token0,
                                              address indexed token1,
                                              uint24 indexed fee,
                                              int24 tickSpacing,
                                              address pool
                                          );
                                          /// @notice Emitted when a new fee amount is enabled for pool creation via the factory
                                          /// @param fee The enabled fee, denominated in hundredths of a bip
                                          /// @param tickSpacing The minimum number of ticks between initialized ticks for pools created with the given fee
                                          event FeeAmountEnabled(uint24 indexed fee, int24 indexed tickSpacing);
                                          /// @notice Returns the current owner of the factory
                                          /// @dev Can be changed by the current owner via setOwner
                                          /// @return The address of the factory owner
                                          function owner() external view returns (address);
                                          /// @notice Returns the tick spacing for a given fee amount, if enabled, or 0 if not enabled
                                          /// @dev A fee amount can never be removed, so this value should be hard coded or cached in the calling context
                                          /// @param fee The enabled fee, denominated in hundredths of a bip. Returns 0 in case of unenabled fee
                                          /// @return The tick spacing
                                          function feeAmountTickSpacing(uint24 fee) external view returns (int24);
                                          /// @notice Returns the pool address for a given pair of tokens and a fee, or address 0 if it does not exist
                                          /// @dev tokenA and tokenB may be passed in either token0/token1 or token1/token0 order
                                          /// @param tokenA The contract address of either token0 or token1
                                          /// @param tokenB The contract address of the other token
                                          /// @param fee The fee collected upon every swap in the pool, denominated in hundredths of a bip
                                          /// @return pool The pool address
                                          function getPool(
                                              address tokenA,
                                              address tokenB,
                                              uint24 fee
                                          ) external view returns (address pool);
                                          /// @notice Creates a pool for the given two tokens and fee
                                          /// @param tokenA One of the two tokens in the desired pool
                                          /// @param tokenB The other of the two tokens in the desired pool
                                          /// @param fee The desired fee for the pool
                                          /// @dev tokenA and tokenB may be passed in either order: token0/token1 or token1/token0. tickSpacing is retrieved
                                          /// from the fee. The call will revert if the pool already exists, the fee is invalid, or the token arguments
                                          /// are invalid.
                                          /// @return pool The address of the newly created pool
                                          function createPool(
                                              address tokenA,
                                              address tokenB,
                                              uint24 fee
                                          ) external returns (address pool);
                                          /// @notice Updates the owner of the factory
                                          /// @dev Must be called by the current owner
                                          /// @param _owner The new owner of the factory
                                          function setOwner(address _owner) external;
                                          /// @notice Enables a fee amount with the given tickSpacing
                                          /// @dev Fee amounts may never be removed once enabled
                                          /// @param fee The fee amount to enable, denominated in hundredths of a bip (i.e. 1e-6)
                                          /// @param tickSpacing The spacing between ticks to be enforced for all pools created with the given fee amount
                                          function enableFeeAmount(uint24 fee, int24 tickSpacing) external;
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Minimal ERC20 interface for Uniswap
                                      /// @notice Contains a subset of the full ERC20 interface that is used in Uniswap V3
                                      interface IERC20Minimal {
                                          /// @notice Returns the balance of a token
                                          /// @param account The account for which to look up the number of tokens it has, i.e. its balance
                                          /// @return The number of tokens held by the account
                                          function balanceOf(address account) external view returns (uint256);
                                          /// @notice Transfers the amount of token from the `msg.sender` to the recipient
                                          /// @param recipient The account that will receive the amount transferred
                                          /// @param amount The number of tokens to send from the sender to the recipient
                                          /// @return Returns true for a successful transfer, false for an unsuccessful transfer
                                          function transfer(address recipient, uint256 amount) external returns (bool);
                                          /// @notice Returns the current allowance given to a spender by an owner
                                          /// @param owner The account of the token owner
                                          /// @param spender The account of the token spender
                                          /// @return The current allowance granted by `owner` to `spender`
                                          function allowance(address owner, address spender) external view returns (uint256);
                                          /// @notice Sets the allowance of a spender from the `msg.sender` to the value `amount`
                                          /// @param spender The account which will be allowed to spend a given amount of the owners tokens
                                          /// @param amount The amount of tokens allowed to be used by `spender`
                                          /// @return Returns true for a successful approval, false for unsuccessful
                                          function approve(address spender, uint256 amount) external returns (bool);
                                          /// @notice Transfers `amount` tokens from `sender` to `recipient` up to the allowance given to the `msg.sender`
                                          /// @param sender The account from which the transfer will be initiated
                                          /// @param recipient The recipient of the transfer
                                          /// @param amount The amount of the transfer
                                          /// @return Returns true for a successful transfer, false for unsuccessful
                                          function transferFrom(
                                              address sender,
                                              address recipient,
                                              uint256 amount
                                          ) external returns (bool);
                                          /// @notice Event emitted when tokens are transferred from one address to another, either via `#transfer` or `#transferFrom`.
                                          /// @param from The account from which the tokens were sent, i.e. the balance decreased
                                          /// @param to The account to which the tokens were sent, i.e. the balance increased
                                          /// @param value The amount of tokens that were transferred
                                          event Transfer(address indexed from, address indexed to, uint256 value);
                                          /// @notice Event emitted when the approval amount for the spender of a given owner's tokens changes.
                                          /// @param owner The account that approved spending of its tokens
                                          /// @param spender The account for which the spending allowance was modified
                                          /// @param value The new allowance from the owner to the spender
                                          event Approval(address indexed owner, address indexed spender, uint256 value);
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Callback for IUniswapV3PoolActions#mint
                                      /// @notice Any contract that calls IUniswapV3PoolActions#mint must implement this interface
                                      interface IUniswapV3MintCallback {
                                          /// @notice Called to `msg.sender` after minting liquidity to a position from IUniswapV3Pool#mint.
                                          /// @dev In the implementation you must pay the pool tokens owed for the minted liquidity.
                                          /// The caller of this method must be checked to be a UniswapV3Pool deployed by the canonical UniswapV3Factory.
                                          /// @param amount0Owed The amount of token0 due to the pool for the minted liquidity
                                          /// @param amount1Owed The amount of token1 due to the pool for the minted liquidity
                                          /// @param data Any data passed through by the caller via the IUniswapV3PoolActions#mint call
                                          function uniswapV3MintCallback(
                                              uint256 amount0Owed,
                                              uint256 amount1Owed,
                                              bytes calldata data
                                          ) external;
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Callback for IUniswapV3PoolActions#swap
                                      /// @notice Any contract that calls IUniswapV3PoolActions#swap must implement this interface
                                      interface IUniswapV3SwapCallback {
                                          /// @notice Called to `msg.sender` after executing a swap via IUniswapV3Pool#swap.
                                          /// @dev In the implementation you must pay the pool tokens owed for the swap.
                                          /// The caller of this method must be checked to be a UniswapV3Pool deployed by the canonical UniswapV3Factory.
                                          /// amount0Delta and amount1Delta can both be 0 if no tokens were swapped.
                                          /// @param amount0Delta The amount of token0 that was sent (negative) or must be received (positive) by the pool by
                                          /// the end of the swap. If positive, the callback must send that amount of token0 to the pool.
                                          /// @param amount1Delta The amount of token1 that was sent (negative) or must be received (positive) by the pool by
                                          /// the end of the swap. If positive, the callback must send that amount of token1 to the pool.
                                          /// @param data Any data passed through by the caller via the IUniswapV3PoolActions#swap call
                                          function uniswapV3SwapCallback(
                                              int256 amount0Delta,
                                              int256 amount1Delta,
                                              bytes calldata data
                                          ) external;
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Callback for IUniswapV3PoolActions#flash
                                      /// @notice Any contract that calls IUniswapV3PoolActions#flash must implement this interface
                                      interface IUniswapV3FlashCallback {
                                          /// @notice Called to `msg.sender` after transferring to the recipient from IUniswapV3Pool#flash.
                                          /// @dev In the implementation you must repay the pool the tokens sent by flash plus the computed fee amounts.
                                          /// The caller of this method must be checked to be a UniswapV3Pool deployed by the canonical UniswapV3Factory.
                                          /// @param fee0 The fee amount in token0 due to the pool by the end of the flash
                                          /// @param fee1 The fee amount in token1 due to the pool by the end of the flash
                                          /// @param data Any data passed through by the caller via the IUniswapV3PoolActions#flash call
                                          function uniswapV3FlashCallback(
                                              uint256 fee0,
                                              uint256 fee1,
                                              bytes calldata data
                                          ) external;
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Pool state that never changes
                                      /// @notice These parameters are fixed for a pool forever, i.e., the methods will always return the same values
                                      interface IUniswapV3PoolImmutables {
                                          /// @notice The contract that deployed the pool, which must adhere to the IUniswapV3Factory interface
                                          /// @return The contract address
                                          function factory() external view returns (address);
                                          /// @notice The first of the two tokens of the pool, sorted by address
                                          /// @return The token contract address
                                          function token0() external view returns (address);
                                          /// @notice The second of the two tokens of the pool, sorted by address
                                          /// @return The token contract address
                                          function token1() external view returns (address);
                                          /// @notice The pool's fee in hundredths of a bip, i.e. 1e-6
                                          /// @return The fee
                                          function fee() external view returns (uint24);
                                          /// @notice The pool tick spacing
                                          /// @dev Ticks can only be used at multiples of this value, minimum of 1 and always positive
                                          /// e.g.: a tickSpacing of 3 means ticks can be initialized every 3rd tick, i.e., ..., -6, -3, 0, 3, 6, ...
                                          /// This value is an int24 to avoid casting even though it is always positive.
                                          /// @return The tick spacing
                                          function tickSpacing() external view returns (int24);
                                          /// @notice The maximum amount of position liquidity that can use any tick in the range
                                          /// @dev This parameter is enforced per tick to prevent liquidity from overflowing a uint128 at any point, and
                                          /// also prevents out-of-range liquidity from being used to prevent adding in-range liquidity to a pool
                                          /// @return The max amount of liquidity per tick
                                          function maxLiquidityPerTick() external view returns (uint128);
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Pool state that can change
                                      /// @notice These methods compose the pool's state, and can change with any frequency including multiple times
                                      /// per transaction
                                      interface IUniswapV3PoolState {
                                          /// @notice The 0th storage slot in the pool stores many values, and is exposed as a single method to save gas
                                          /// when accessed externally.
                                          /// @return sqrtPriceX96 The current price of the pool as a sqrt(token1/token0) Q64.96 value
                                          /// tick The current tick of the pool, i.e. according to the last tick transition that was run.
                                          /// This value may not always be equal to SqrtTickMath.getTickAtSqrtRatio(sqrtPriceX96) if the price is on a tick
                                          /// boundary.
                                          /// observationIndex The index of the last oracle observation that was written,
                                          /// observationCardinality The current maximum number of observations stored in the pool,
                                          /// observationCardinalityNext The next maximum number of observations, to be updated when the observation.
                                          /// feeProtocol The protocol fee for both tokens of the pool.
                                          /// Encoded as two 4 bit values, where the protocol fee of token1 is shifted 4 bits and the protocol fee of token0
                                          /// is the lower 4 bits. Used as the denominator of a fraction of the swap fee, e.g. 4 means 1/4th of the swap fee.
                                          /// unlocked Whether the pool is currently locked to reentrancy
                                          function slot0()
                                              external
                                              view
                                              returns (
                                                  uint160 sqrtPriceX96,
                                                  int24 tick,
                                                  uint16 observationIndex,
                                                  uint16 observationCardinality,
                                                  uint16 observationCardinalityNext,
                                                  uint8 feeProtocol,
                                                  bool unlocked
                                              );
                                          /// @notice The fee growth as a Q128.128 fees of token0 collected per unit of liquidity for the entire life of the pool
                                          /// @dev This value can overflow the uint256
                                          function feeGrowthGlobal0X128() external view returns (uint256);
                                          /// @notice The fee growth as a Q128.128 fees of token1 collected per unit of liquidity for the entire life of the pool
                                          /// @dev This value can overflow the uint256
                                          function feeGrowthGlobal1X128() external view returns (uint256);
                                          /// @notice The amounts of token0 and token1 that are owed to the protocol
                                          /// @dev Protocol fees will never exceed uint128 max in either token
                                          function protocolFees() external view returns (uint128 token0, uint128 token1);
                                          /// @notice The currently in range liquidity available to the pool
                                          /// @dev This value has no relationship to the total liquidity across all ticks
                                          function liquidity() external view returns (uint128);
                                          /// @notice Look up information about a specific tick in the pool
                                          /// @param tick The tick to look up
                                          /// @return liquidityGross the total amount of position liquidity that uses the pool either as tick lower or
                                          /// tick upper,
                                          /// liquidityNet how much liquidity changes when the pool price crosses the tick,
                                          /// feeGrowthOutside0X128 the fee growth on the other side of the tick from the current tick in token0,
                                          /// feeGrowthOutside1X128 the fee growth on the other side of the tick from the current tick in token1,
                                          /// tickCumulativeOutside the cumulative tick value on the other side of the tick from the current tick
                                          /// secondsPerLiquidityOutsideX128 the seconds spent per liquidity on the other side of the tick from the current tick,
                                          /// secondsOutside the seconds spent on the other side of the tick from the current tick,
                                          /// initialized Set to true if the tick is initialized, i.e. liquidityGross is greater than 0, otherwise equal to false.
                                          /// Outside values can only be used if the tick is initialized, i.e. if liquidityGross is greater than 0.
                                          /// In addition, these values are only relative and must be used only in comparison to previous snapshots for
                                          /// a specific position.
                                          function ticks(int24 tick)
                                              external
                                              view
                                              returns (
                                                  uint128 liquidityGross,
                                                  int128 liquidityNet,
                                                  uint256 feeGrowthOutside0X128,
                                                  uint256 feeGrowthOutside1X128,
                                                  int56 tickCumulativeOutside,
                                                  uint160 secondsPerLiquidityOutsideX128,
                                                  uint32 secondsOutside,
                                                  bool initialized
                                              );
                                          /// @notice Returns 256 packed tick initialized boolean values. See TickBitmap for more information
                                          function tickBitmap(int16 wordPosition) external view returns (uint256);
                                          /// @notice Returns the information about a position by the position's key
                                          /// @param key The position's key is a hash of a preimage composed by the owner, tickLower and tickUpper
                                          /// @return _liquidity The amount of liquidity in the position,
                                          /// Returns feeGrowthInside0LastX128 fee growth of token0 inside the tick range as of the last mint/burn/poke,
                                          /// Returns feeGrowthInside1LastX128 fee growth of token1 inside the tick range as of the last mint/burn/poke,
                                          /// Returns tokensOwed0 the computed amount of token0 owed to the position as of the last mint/burn/poke,
                                          /// Returns tokensOwed1 the computed amount of token1 owed to the position as of the last mint/burn/poke
                                          function positions(bytes32 key)
                                              external
                                              view
                                              returns (
                                                  uint128 _liquidity,
                                                  uint256 feeGrowthInside0LastX128,
                                                  uint256 feeGrowthInside1LastX128,
                                                  uint128 tokensOwed0,
                                                  uint128 tokensOwed1
                                              );
                                          /// @notice Returns data about a specific observation index
                                          /// @param index The element of the observations array to fetch
                                          /// @dev You most likely want to use #observe() instead of this method to get an observation as of some amount of time
                                          /// ago, rather than at a specific index in the array.
                                          /// @return blockTimestamp The timestamp of the observation,
                                          /// Returns tickCumulative the tick multiplied by seconds elapsed for the life of the pool as of the observation timestamp,
                                          /// Returns secondsPerLiquidityCumulativeX128 the seconds per in range liquidity for the life of the pool as of the observation timestamp,
                                          /// Returns initialized whether the observation has been initialized and the values are safe to use
                                          function observations(uint256 index)
                                              external
                                              view
                                              returns (
                                                  uint32 blockTimestamp,
                                                  int56 tickCumulative,
                                                  uint160 secondsPerLiquidityCumulativeX128,
                                                  bool initialized
                                              );
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Pool state that is not stored
                                      /// @notice Contains view functions to provide information about the pool that is computed rather than stored on the
                                      /// blockchain. The functions here may have variable gas costs.
                                      interface IUniswapV3PoolDerivedState {
                                          /// @notice Returns the cumulative tick and liquidity as of each timestamp `secondsAgo` from the current block timestamp
                                          /// @dev To get a time weighted average tick or liquidity-in-range, you must call this with two values, one representing
                                          /// the beginning of the period and another for the end of the period. E.g., to get the last hour time-weighted average tick,
                                          /// you must call it with secondsAgos = [3600, 0].
                                          /// @dev The time weighted average tick represents the geometric time weighted average price of the pool, in
                                          /// log base sqrt(1.0001) of token1 / token0. The TickMath library can be used to go from a tick value to a ratio.
                                          /// @param secondsAgos From how long ago each cumulative tick and liquidity value should be returned
                                          /// @return tickCumulatives Cumulative tick values as of each `secondsAgos` from the current block timestamp
                                          /// @return secondsPerLiquidityCumulativeX128s Cumulative seconds per liquidity-in-range value as of each `secondsAgos` from the current block
                                          /// timestamp
                                          function observe(uint32[] calldata secondsAgos)
                                              external
                                              view
                                              returns (int56[] memory tickCumulatives, uint160[] memory secondsPerLiquidityCumulativeX128s);
                                          /// @notice Returns a snapshot of the tick cumulative, seconds per liquidity and seconds inside a tick range
                                          /// @dev Snapshots must only be compared to other snapshots, taken over a period for which a position existed.
                                          /// I.e., snapshots cannot be compared if a position is not held for the entire period between when the first
                                          /// snapshot is taken and the second snapshot is taken.
                                          /// @param tickLower The lower tick of the range
                                          /// @param tickUpper The upper tick of the range
                                          /// @return tickCumulativeInside The snapshot of the tick accumulator for the range
                                          /// @return secondsPerLiquidityInsideX128 The snapshot of seconds per liquidity for the range
                                          /// @return secondsInside The snapshot of seconds per liquidity for the range
                                          function snapshotCumulativesInside(int24 tickLower, int24 tickUpper)
                                              external
                                              view
                                              returns (
                                                  int56 tickCumulativeInside,
                                                  uint160 secondsPerLiquidityInsideX128,
                                                  uint32 secondsInside
                                              );
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Permissionless pool actions
                                      /// @notice Contains pool methods that can be called by anyone
                                      interface IUniswapV3PoolActions {
                                          /// @notice Sets the initial price for the pool
                                          /// @dev Price is represented as a sqrt(amountToken1/amountToken0) Q64.96 value
                                          /// @param sqrtPriceX96 the initial sqrt price of the pool as a Q64.96
                                          function initialize(uint160 sqrtPriceX96) external;
                                          /// @notice Adds liquidity for the given recipient/tickLower/tickUpper position
                                          /// @dev The caller of this method receives a callback in the form of IUniswapV3MintCallback#uniswapV3MintCallback
                                          /// in which they must pay any token0 or token1 owed for the liquidity. The amount of token0/token1 due depends
                                          /// on tickLower, tickUpper, the amount of liquidity, and the current price.
                                          /// @param recipient The address for which the liquidity will be created
                                          /// @param tickLower The lower tick of the position in which to add liquidity
                                          /// @param tickUpper The upper tick of the position in which to add liquidity
                                          /// @param amount The amount of liquidity to mint
                                          /// @param data Any data that should be passed through to the callback
                                          /// @return amount0 The amount of token0 that was paid to mint the given amount of liquidity. Matches the value in the callback
                                          /// @return amount1 The amount of token1 that was paid to mint the given amount of liquidity. Matches the value in the callback
                                          function mint(
                                              address recipient,
                                              int24 tickLower,
                                              int24 tickUpper,
                                              uint128 amount,
                                              bytes calldata data
                                          ) external returns (uint256 amount0, uint256 amount1);
                                          /// @notice Collects tokens owed to a position
                                          /// @dev Does not recompute fees earned, which must be done either via mint or burn of any amount of liquidity.
                                          /// Collect must be called by the position owner. To withdraw only token0 or only token1, amount0Requested or
                                          /// amount1Requested may be set to zero. To withdraw all tokens owed, caller may pass any value greater than the
                                          /// actual tokens owed, e.g. type(uint128).max. Tokens owed may be from accumulated swap fees or burned liquidity.
                                          /// @param recipient The address which should receive the fees collected
                                          /// @param tickLower The lower tick of the position for which to collect fees
                                          /// @param tickUpper The upper tick of the position for which to collect fees
                                          /// @param amount0Requested How much token0 should be withdrawn from the fees owed
                                          /// @param amount1Requested How much token1 should be withdrawn from the fees owed
                                          /// @return amount0 The amount of fees collected in token0
                                          /// @return amount1 The amount of fees collected in token1
                                          function collect(
                                              address recipient,
                                              int24 tickLower,
                                              int24 tickUpper,
                                              uint128 amount0Requested,
                                              uint128 amount1Requested
                                          ) external returns (uint128 amount0, uint128 amount1);
                                          /// @notice Burn liquidity from the sender and account tokens owed for the liquidity to the position
                                          /// @dev Can be used to trigger a recalculation of fees owed to a position by calling with an amount of 0
                                          /// @dev Fees must be collected separately via a call to #collect
                                          /// @param tickLower The lower tick of the position for which to burn liquidity
                                          /// @param tickUpper The upper tick of the position for which to burn liquidity
                                          /// @param amount How much liquidity to burn
                                          /// @return amount0 The amount of token0 sent to the recipient
                                          /// @return amount1 The amount of token1 sent to the recipient
                                          function burn(
                                              int24 tickLower,
                                              int24 tickUpper,
                                              uint128 amount
                                          ) external returns (uint256 amount0, uint256 amount1);
                                          /// @notice Swap token0 for token1, or token1 for token0
                                          /// @dev The caller of this method receives a callback in the form of IUniswapV3SwapCallback#uniswapV3SwapCallback
                                          /// @param recipient The address to receive the output of the swap
                                          /// @param zeroForOne The direction of the swap, true for token0 to token1, false for token1 to token0
                                          /// @param amountSpecified The amount of the swap, which implicitly configures the swap as exact input (positive), or exact output (negative)
                                          /// @param sqrtPriceLimitX96 The Q64.96 sqrt price limit. If zero for one, the price cannot be less than this
                                          /// value after the swap. If one for zero, the price cannot be greater than this value after the swap
                                          /// @param data Any data to be passed through to the callback
                                          /// @return amount0 The delta of the balance of token0 of the pool, exact when negative, minimum when positive
                                          /// @return amount1 The delta of the balance of token1 of the pool, exact when negative, minimum when positive
                                          function swap(
                                              address recipient,
                                              bool zeroForOne,
                                              int256 amountSpecified,
                                              uint160 sqrtPriceLimitX96,
                                              bytes calldata data
                                          ) external returns (int256 amount0, int256 amount1);
                                          /// @notice Receive token0 and/or token1 and pay it back, plus a fee, in the callback
                                          /// @dev The caller of this method receives a callback in the form of IUniswapV3FlashCallback#uniswapV3FlashCallback
                                          /// @dev Can be used to donate underlying tokens pro-rata to currently in-range liquidity providers by calling
                                          /// with 0 amount{0,1} and sending the donation amount(s) from the callback
                                          /// @param recipient The address which will receive the token0 and token1 amounts
                                          /// @param amount0 The amount of token0 to send
                                          /// @param amount1 The amount of token1 to send
                                          /// @param data Any data to be passed through to the callback
                                          function flash(
                                              address recipient,
                                              uint256 amount0,
                                              uint256 amount1,
                                              bytes calldata data
                                          ) external;
                                          /// @notice Increase the maximum number of price and liquidity observations that this pool will store
                                          /// @dev This method is no-op if the pool already has an observationCardinalityNext greater than or equal to
                                          /// the input observationCardinalityNext.
                                          /// @param observationCardinalityNext The desired minimum number of observations for the pool to store
                                          function increaseObservationCardinalityNext(uint16 observationCardinalityNext) external;
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Permissioned pool actions
                                      /// @notice Contains pool methods that may only be called by the factory owner
                                      interface IUniswapV3PoolOwnerActions {
                                          /// @notice Set the denominator of the protocol's % share of the fees
                                          /// @param feeProtocol0 new protocol fee for token0 of the pool
                                          /// @param feeProtocol1 new protocol fee for token1 of the pool
                                          function setFeeProtocol(uint8 feeProtocol0, uint8 feeProtocol1) external;
                                          /// @notice Collect the protocol fee accrued to the pool
                                          /// @param recipient The address to which collected protocol fees should be sent
                                          /// @param amount0Requested The maximum amount of token0 to send, can be 0 to collect fees in only token1
                                          /// @param amount1Requested The maximum amount of token1 to send, can be 0 to collect fees in only token0
                                          /// @return amount0 The protocol fee collected in token0
                                          /// @return amount1 The protocol fee collected in token1
                                          function collectProtocol(
                                              address recipient,
                                              uint128 amount0Requested,
                                              uint128 amount1Requested
                                          ) external returns (uint128 amount0, uint128 amount1);
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Events emitted by a pool
                                      /// @notice Contains all events emitted by the pool
                                      interface IUniswapV3PoolEvents {
                                          /// @notice Emitted exactly once by a pool when #initialize is first called on the pool
                                          /// @dev Mint/Burn/Swap cannot be emitted by the pool before Initialize
                                          /// @param sqrtPriceX96 The initial sqrt price of the pool, as a Q64.96
                                          /// @param tick The initial tick of the pool, i.e. log base 1.0001 of the starting price of the pool
                                          event Initialize(uint160 sqrtPriceX96, int24 tick);
                                          /// @notice Emitted when liquidity is minted for a given position
                                          /// @param sender The address that minted the liquidity
                                          /// @param owner The owner of the position and recipient of any minted liquidity
                                          /// @param tickLower The lower tick of the position
                                          /// @param tickUpper The upper tick of the position
                                          /// @param amount The amount of liquidity minted to the position range
                                          /// @param amount0 How much token0 was required for the minted liquidity
                                          /// @param amount1 How much token1 was required for the minted liquidity
                                          event Mint(
                                              address sender,
                                              address indexed owner,
                                              int24 indexed tickLower,
                                              int24 indexed tickUpper,
                                              uint128 amount,
                                              uint256 amount0,
                                              uint256 amount1
                                          );
                                          /// @notice Emitted when fees are collected by the owner of a position
                                          /// @dev Collect events may be emitted with zero amount0 and amount1 when the caller chooses not to collect fees
                                          /// @param owner The owner of the position for which fees are collected
                                          /// @param tickLower The lower tick of the position
                                          /// @param tickUpper The upper tick of the position
                                          /// @param amount0 The amount of token0 fees collected
                                          /// @param amount1 The amount of token1 fees collected
                                          event Collect(
                                              address indexed owner,
                                              address recipient,
                                              int24 indexed tickLower,
                                              int24 indexed tickUpper,
                                              uint128 amount0,
                                              uint128 amount1
                                          );
                                          /// @notice Emitted when a position's liquidity is removed
                                          /// @dev Does not withdraw any fees earned by the liquidity position, which must be withdrawn via #collect
                                          /// @param owner The owner of the position for which liquidity is removed
                                          /// @param tickLower The lower tick of the position
                                          /// @param tickUpper The upper tick of the position
                                          /// @param amount The amount of liquidity to remove
                                          /// @param amount0 The amount of token0 withdrawn
                                          /// @param amount1 The amount of token1 withdrawn
                                          event Burn(
                                              address indexed owner,
                                              int24 indexed tickLower,
                                              int24 indexed tickUpper,
                                              uint128 amount,
                                              uint256 amount0,
                                              uint256 amount1
                                          );
                                          /// @notice Emitted by the pool for any swaps between token0 and token1
                                          /// @param sender The address that initiated the swap call, and that received the callback
                                          /// @param recipient The address that received the output of the swap
                                          /// @param amount0 The delta of the token0 balance of the pool
                                          /// @param amount1 The delta of the token1 balance of the pool
                                          /// @param sqrtPriceX96 The sqrt(price) of the pool after the swap, as a Q64.96
                                          /// @param liquidity The liquidity of the pool after the swap
                                          /// @param tick The log base 1.0001 of price of the pool after the swap
                                          event Swap(
                                              address indexed sender,
                                              address indexed recipient,
                                              int256 amount0,
                                              int256 amount1,
                                              uint160 sqrtPriceX96,
                                              uint128 liquidity,
                                              int24 tick
                                          );
                                          /// @notice Emitted by the pool for any flashes of token0/token1
                                          /// @param sender The address that initiated the swap call, and that received the callback
                                          /// @param recipient The address that received the tokens from flash
                                          /// @param amount0 The amount of token0 that was flashed
                                          /// @param amount1 The amount of token1 that was flashed
                                          /// @param paid0 The amount of token0 paid for the flash, which can exceed the amount0 plus the fee
                                          /// @param paid1 The amount of token1 paid for the flash, which can exceed the amount1 plus the fee
                                          event Flash(
                                              address indexed sender,
                                              address indexed recipient,
                                              uint256 amount0,
                                              uint256 amount1,
                                              uint256 paid0,
                                              uint256 paid1
                                          );
                                          /// @notice Emitted by the pool for increases to the number of observations that can be stored
                                          /// @dev observationCardinalityNext is not the observation cardinality until an observation is written at the index
                                          /// just before a mint/swap/burn.
                                          /// @param observationCardinalityNextOld The previous value of the next observation cardinality
                                          /// @param observationCardinalityNextNew The updated value of the next observation cardinality
                                          event IncreaseObservationCardinalityNext(
                                              uint16 observationCardinalityNextOld,
                                              uint16 observationCardinalityNextNew
                                          );
                                          /// @notice Emitted when the protocol fee is changed by the pool
                                          /// @param feeProtocol0Old The previous value of the token0 protocol fee
                                          /// @param feeProtocol1Old The previous value of the token1 protocol fee
                                          /// @param feeProtocol0New The updated value of the token0 protocol fee
                                          /// @param feeProtocol1New The updated value of the token1 protocol fee
                                          event SetFeeProtocol(uint8 feeProtocol0Old, uint8 feeProtocol1Old, uint8 feeProtocol0New, uint8 feeProtocol1New);
                                          /// @notice Emitted when the collected protocol fees are withdrawn by the factory owner
                                          /// @param sender The address that collects the protocol fees
                                          /// @param recipient The address that receives the collected protocol fees
                                          /// @param amount0 The amount of token0 protocol fees that is withdrawn
                                          /// @param amount0 The amount of token1 protocol fees that is withdrawn
                                          event CollectProtocol(address indexed sender, address indexed recipient, uint128 amount0, uint128 amount1);
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title BitMath
                                      /// @dev This library provides functionality for computing bit properties of an unsigned integer
                                      library BitMath {
                                          /// @notice Returns the index of the most significant bit of the number,
                                          ///     where the least significant bit is at index 0 and the most significant bit is at index 255
                                          /// @dev The function satisfies the property:
                                          ///     x >= 2**mostSignificantBit(x) and x < 2**(mostSignificantBit(x)+1)
                                          /// @param x the value for which to compute the most significant bit, must be greater than 0
                                          /// @return r the index of the most significant bit
                                          function mostSignificantBit(uint256 x) internal pure returns (uint8 r) {
                                              require(x > 0);
                                              if (x >= 0x100000000000000000000000000000000) {
                                                  x >>= 128;
                                                  r += 128;
                                              }
                                              if (x >= 0x10000000000000000) {
                                                  x >>= 64;
                                                  r += 64;
                                              }
                                              if (x >= 0x100000000) {
                                                  x >>= 32;
                                                  r += 32;
                                              }
                                              if (x >= 0x10000) {
                                                  x >>= 16;
                                                  r += 16;
                                              }
                                              if (x >= 0x100) {
                                                  x >>= 8;
                                                  r += 8;
                                              }
                                              if (x >= 0x10) {
                                                  x >>= 4;
                                                  r += 4;
                                              }
                                              if (x >= 0x4) {
                                                  x >>= 2;
                                                  r += 2;
                                              }
                                              if (x >= 0x2) r += 1;
                                          }
                                          /// @notice Returns the index of the least significant bit of the number,
                                          ///     where the least significant bit is at index 0 and the most significant bit is at index 255
                                          /// @dev The function satisfies the property:
                                          ///     (x & 2**leastSignificantBit(x)) != 0 and (x & (2**(leastSignificantBit(x)) - 1)) == 0)
                                          /// @param x the value for which to compute the least significant bit, must be greater than 0
                                          /// @return r the index of the least significant bit
                                          function leastSignificantBit(uint256 x) internal pure returns (uint8 r) {
                                              require(x > 0);
                                              r = 255;
                                              if (x & type(uint128).max > 0) {
                                                  r -= 128;
                                              } else {
                                                  x >>= 128;
                                              }
                                              if (x & type(uint64).max > 0) {
                                                  r -= 64;
                                              } else {
                                                  x >>= 64;
                                              }
                                              if (x & type(uint32).max > 0) {
                                                  r -= 32;
                                              } else {
                                                  x >>= 32;
                                              }
                                              if (x & type(uint16).max > 0) {
                                                  r -= 16;
                                              } else {
                                                  x >>= 16;
                                              }
                                              if (x & type(uint8).max > 0) {
                                                  r -= 8;
                                              } else {
                                                  x >>= 8;
                                              }
                                              if (x & 0xf > 0) {
                                                  r -= 4;
                                              } else {
                                                  x >>= 4;
                                              }
                                              if (x & 0x3 > 0) {
                                                  r -= 2;
                                              } else {
                                                  x >>= 2;
                                              }
                                              if (x & 0x1 > 0) r -= 1;
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.5.0;
                                      /// @title Math functions that do not check inputs or outputs
                                      /// @notice Contains methods that perform common math functions but do not do any overflow or underflow checks
                                      library UnsafeMath {
                                          /// @notice Returns ceil(x / y)
                                          /// @dev division by 0 has unspecified behavior, and must be checked externally
                                          /// @param x The dividend
                                          /// @param y The divisor
                                          /// @return z The quotient, ceil(x / y)
                                          function divRoundingUp(uint256 x, uint256 y) internal pure returns (uint256 z) {
                                              assembly {
                                                  z := add(div(x, y), gt(mod(x, y), 0))
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: GPL-2.0-or-later
                                      pragma solidity >=0.4.0;
                                      /// @title FixedPoint96
                                      /// @notice A library for handling binary fixed point numbers, see https://en.wikipedia.org/wiki/Q_(number_format)
                                      /// @dev Used in SqrtPriceMath.sol
                                      library FixedPoint96 {
                                          uint8 internal constant RESOLUTION = 96;
                                          uint256 internal constant Q96 = 0x1000000000000000000000000;
                                      }
                                      

                                      File 5 of 11: ZeroEx
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
                                      import "./migrations/LibBootstrap.sol";
                                      import "./features/Bootstrap.sol";
                                      import "./storage/LibProxyStorage.sol";
                                      import "./errors/LibProxyRichErrors.sol";
                                      /// @dev An extensible proxy contract that serves as a universal entry point for
                                      ///      interacting with the 0x protocol.
                                      contract ZeroEx {
                                          // solhint-disable separate-by-one-line-in-contract,indent,var-name-mixedcase
                                          using LibBytesV06 for bytes;
                                          /// @dev Construct this contract and register the `Bootstrap` feature.
                                          ///      After constructing this contract, `bootstrap()` should be called
                                          ///      to seed the initial feature set.
                                          constructor() public {
                                              // Temporarily create and register the bootstrap feature.
                                              // It will deregister itself after `bootstrap()` has been called.
                                              Bootstrap bootstrap = new Bootstrap(msg.sender);
                                              LibProxyStorage.getStorage().impls[bootstrap.bootstrap.selector] =
                                                  address(bootstrap);
                                          }
                                          // solhint-disable state-visibility
                                          /// @dev Forwards calls to the appropriate implementation contract.
                                          fallback() external payable {
                                              bytes4 selector = msg.data.readBytes4(0);
                                              address impl = getFunctionImplementation(selector);
                                              if (impl == address(0)) {
                                                  _revertWithData(LibProxyRichErrors.NotImplementedError(selector));
                                              }
                                              (bool success, bytes memory resultData) = impl.delegatecall(msg.data);
                                              if (!success) {
                                                  _revertWithData(resultData);
                                              }
                                              _returnWithData(resultData);
                                          }
                                          /// @dev Fallback for just receiving ether.
                                          receive() external payable {}
                                          // solhint-enable state-visibility
                                          /// @dev Get the implementation contract of a registered function.
                                          /// @param selector The function selector.
                                          /// @return impl The implementation contract address.
                                          function getFunctionImplementation(bytes4 selector)
                                              public
                                              view
                                              returns (address impl)
                                          {
                                              return LibProxyStorage.getStorage().impls[selector];
                                          }
                                          /// @dev Revert with arbitrary bytes.
                                          /// @param data Revert data.
                                          function _revertWithData(bytes memory data) private pure {
                                              assembly { revert(add(data, 32), mload(data)) }
                                          }
                                          /// @dev Return with arbitrary bytes.
                                          /// @param data Return data.
                                          function _returnWithData(bytes memory data) private pure {
                                              assembly { return(add(data, 32), mload(data)) }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./errors/LibBytesRichErrorsV06.sol";
                                      import "./errors/LibRichErrorsV06.sol";
                                      library LibBytesV06 {
                                          using LibBytesV06 for bytes;
                                          /// @dev Gets the memory address for a byte array.
                                          /// @param input Byte array to lookup.
                                          /// @return memoryAddress Memory address of byte array. This
                                          ///         points to the header of the byte array which contains
                                          ///         the length.
                                          function rawAddress(bytes memory input)
                                              internal
                                              pure
                                              returns (uint256 memoryAddress)
                                          {
                                              assembly {
                                                  memoryAddress := input
                                              }
                                              return memoryAddress;
                                          }
                                          /// @dev Gets the memory address for the contents of a byte array.
                                          /// @param input Byte array to lookup.
                                          /// @return memoryAddress Memory address of the contents of the byte array.
                                          function contentAddress(bytes memory input)
                                              internal
                                              pure
                                              returns (uint256 memoryAddress)
                                          {
                                              assembly {
                                                  memoryAddress := add(input, 32)
                                              }
                                              return memoryAddress;
                                          }
                                          /// @dev Copies `length` bytes from memory location `source` to `dest`.
                                          /// @param dest memory address to copy bytes to.
                                          /// @param source memory address to copy bytes from.
                                          /// @param length number of bytes to copy.
                                          function memCopy(
                                              uint256 dest,
                                              uint256 source,
                                              uint256 length
                                          )
                                              internal
                                              pure
                                          {
                                              if (length < 32) {
                                                  // Handle a partial word by reading destination and masking
                                                  // off the bits we are interested in.
                                                  // This correctly handles overlap, zero lengths and source == dest
                                                  assembly {
                                                      let mask := sub(exp(256, sub(32, length)), 1)
                                                      let s := and(mload(source), not(mask))
                                                      let d := and(mload(dest), mask)
                                                      mstore(dest, or(s, d))
                                                  }
                                              } else {
                                                  // Skip the O(length) loop when source == dest.
                                                  if (source == dest) {
                                                      return;
                                                  }
                                                  // For large copies we copy whole words at a time. The final
                                                  // word is aligned to the end of the range (instead of after the
                                                  // previous) to handle partial words. So a copy will look like this:
                                                  //
                                                  //  ####
                                                  //      ####
                                                  //          ####
                                                  //            ####
                                                  //
                                                  // We handle overlap in the source and destination range by
                                                  // changing the copying direction. This prevents us from
                                                  // overwriting parts of source that we still need to copy.
                                                  //
                                                  // This correctly handles source == dest
                                                  //
                                                  if (source > dest) {
                                                      assembly {
                                                          // We subtract 32 from `sEnd` and `dEnd` because it
                                                          // is easier to compare with in the loop, and these
                                                          // are also the addresses we need for copying the
                                                          // last bytes.
                                                          length := sub(length, 32)
                                                          let sEnd := add(source, length)
                                                          let dEnd := add(dest, length)
                                                          // Remember the last 32 bytes of source
                                                          // This needs to be done here and not after the loop
                                                          // because we may have overwritten the last bytes in
                                                          // source already due to overlap.
                                                          let last := mload(sEnd)
                                                          // Copy whole words front to back
                                                          // Note: the first check is always true,
                                                          // this could have been a do-while loop.
                                                          // solhint-disable-next-line no-empty-blocks
                                                          for {} lt(source, sEnd) {} {
                                                              mstore(dest, mload(source))
                                                              source := add(source, 32)
                                                              dest := add(dest, 32)
                                                          }
                                                          // Write the last 32 bytes
                                                          mstore(dEnd, last)
                                                      }
                                                  } else {
                                                      assembly {
                                                          // We subtract 32 from `sEnd` and `dEnd` because those
                                                          // are the starting points when copying a word at the end.
                                                          length := sub(length, 32)
                                                          let sEnd := add(source, length)
                                                          let dEnd := add(dest, length)
                                                          // Remember the first 32 bytes of source
                                                          // This needs to be done here and not after the loop
                                                          // because we may have overwritten the first bytes in
                                                          // source already due to overlap.
                                                          let first := mload(source)
                                                          // Copy whole words back to front
                                                          // We use a signed comparisson here to allow dEnd to become
                                                          // negative (happens when source and dest < 32). Valid
                                                          // addresses in local memory will never be larger than
                                                          // 2**255, so they can be safely re-interpreted as signed.
                                                          // Note: the first check is always true,
                                                          // this could have been a do-while loop.
                                                          // solhint-disable-next-line no-empty-blocks
                                                          for {} slt(dest, dEnd) {} {
                                                              mstore(dEnd, mload(sEnd))
                                                              sEnd := sub(sEnd, 32)
                                                              dEnd := sub(dEnd, 32)
                                                          }
                                                          // Write the first 32 bytes
                                                          mstore(dest, first)
                                                      }
                                                  }
                                              }
                                          }
                                          /// @dev Returns a slices from a byte array.
                                          /// @param b The byte array to take a slice from.
                                          /// @param from The starting index for the slice (inclusive).
                                          /// @param to The final index for the slice (exclusive).
                                          /// @return result The slice containing bytes at indices [from, to)
                                          function slice(
                                              bytes memory b,
                                              uint256 from,
                                              uint256 to
                                          )
                                              internal
                                              pure
                                              returns (bytes memory result)
                                          {
                                              // Ensure that the from and to positions are valid positions for a slice within
                                              // the byte array that is being used.
                                              if (from > to) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.FromLessThanOrEqualsToRequired,
                                                      from,
                                                      to
                                                  ));
                                              }
                                              if (to > b.length) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.ToLessThanOrEqualsLengthRequired,
                                                      to,
                                                      b.length
                                                  ));
                                              }
                                              // Create a new bytes structure and copy contents
                                              result = new bytes(to - from);
                                              memCopy(
                                                  result.contentAddress(),
                                                  b.contentAddress() + from,
                                                  result.length
                                              );
                                              return result;
                                          }
                                          /// @dev Returns a slice from a byte array without preserving the input.
                                          ///      When `from == 0`, the original array will match the slice.
                                          ///      In other cases its state will be corrupted.
                                          /// @param b The byte array to take a slice from. Will be destroyed in the process.
                                          /// @param from The starting index for the slice (inclusive).
                                          /// @param to The final index for the slice (exclusive).
                                          /// @return result The slice containing bytes at indices [from, to)
                                          function sliceDestructive(
                                              bytes memory b,
                                              uint256 from,
                                              uint256 to
                                          )
                                              internal
                                              pure
                                              returns (bytes memory result)
                                          {
                                              // Ensure that the from and to positions are valid positions for a slice within
                                              // the byte array that is being used.
                                              if (from > to) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.FromLessThanOrEqualsToRequired,
                                                      from,
                                                      to
                                                  ));
                                              }
                                              if (to > b.length) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.ToLessThanOrEqualsLengthRequired,
                                                      to,
                                                      b.length
                                                  ));
                                              }
                                              // Create a new bytes structure around [from, to) in-place.
                                              assembly {
                                                  result := add(b, from)
                                                  mstore(result, sub(to, from))
                                              }
                                              return result;
                                          }
                                          /// @dev Pops the last byte off of a byte array by modifying its length.
                                          /// @param b Byte array that will be modified.
                                          /// @return result The byte that was popped off.
                                          function popLastByte(bytes memory b)
                                              internal
                                              pure
                                              returns (bytes1 result)
                                          {
                                              if (b.length == 0) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanZeroRequired,
                                                      b.length,
                                                      0
                                                  ));
                                              }
                                              // Store last byte.
                                              result = b[b.length - 1];
                                              assembly {
                                                  // Decrement length of byte array.
                                                  let newLen := sub(mload(b), 1)
                                                  mstore(b, newLen)
                                              }
                                              return result;
                                          }
                                          /// @dev Tests equality of two byte arrays.
                                          /// @param lhs First byte array to compare.
                                          /// @param rhs Second byte array to compare.
                                          /// @return equal True if arrays are the same. False otherwise.
                                          function equals(
                                              bytes memory lhs,
                                              bytes memory rhs
                                          )
                                              internal
                                              pure
                                              returns (bool equal)
                                          {
                                              // Keccak gas cost is 30 + numWords * 6. This is a cheap way to compare.
                                              // We early exit on unequal lengths, but keccak would also correctly
                                              // handle this.
                                              return lhs.length == rhs.length && keccak256(lhs) == keccak256(rhs);
                                          }
                                          /// @dev Reads an address from a position in a byte array.
                                          /// @param b Byte array containing an address.
                                          /// @param index Index in byte array of address.
                                          /// @return result address from byte array.
                                          function readAddress(
                                              bytes memory b,
                                              uint256 index
                                          )
                                              internal
                                              pure
                                              returns (address result)
                                          {
                                              if (b.length < index + 20) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsTwentyRequired,
                                                      b.length,
                                                      index + 20 // 20 is length of address
                                                  ));
                                              }
                                              // Add offset to index:
                                              // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
                                              // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
                                              index += 20;
                                              // Read address from array memory
                                              assembly {
                                                  // 1. Add index to address of bytes array
                                                  // 2. Load 32-byte word from memory
                                                  // 3. Apply 20-byte mask to obtain address
                                                  result := and(mload(add(b, index)), 0xffffffffffffffffffffffffffffffffffffffff)
                                              }
                                              return result;
                                          }
                                          /// @dev Writes an address into a specific position in a byte array.
                                          /// @param b Byte array to insert address into.
                                          /// @param index Index in byte array of address.
                                          /// @param input Address to put into byte array.
                                          function writeAddress(
                                              bytes memory b,
                                              uint256 index,
                                              address input
                                          )
                                              internal
                                              pure
                                          {
                                              if (b.length < index + 20) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsTwentyRequired,
                                                      b.length,
                                                      index + 20 // 20 is length of address
                                                  ));
                                              }
                                              // Add offset to index:
                                              // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
                                              // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
                                              index += 20;
                                              // Store address into array memory
                                              assembly {
                                                  // The address occupies 20 bytes and mstore stores 32 bytes.
                                                  // First fetch the 32-byte word where we'll be storing the address, then
                                                  // apply a mask so we have only the bytes in the word that the address will not occupy.
                                                  // Then combine these bytes with the address and store the 32 bytes back to memory with mstore.
                                                  // 1. Add index to address of bytes array
                                                  // 2. Load 32-byte word from memory
                                                  // 3. Apply 12-byte mask to obtain extra bytes occupying word of memory where we'll store the address
                                                  let neighbors := and(
                                                      mload(add(b, index)),
                                                      0xffffffffffffffffffffffff0000000000000000000000000000000000000000
                                                  )
                                                  // Make sure input address is clean.
                                                  // (Solidity does not guarantee this)
                                                  input := and(input, 0xffffffffffffffffffffffffffffffffffffffff)
                                                  // Store the neighbors and address into memory
                                                  mstore(add(b, index), xor(input, neighbors))
                                              }
                                          }
                                          /// @dev Reads a bytes32 value from a position in a byte array.
                                          /// @param b Byte array containing a bytes32 value.
                                          /// @param index Index in byte array of bytes32 value.
                                          /// @return result bytes32 value from byte array.
                                          function readBytes32(
                                              bytes memory b,
                                              uint256 index
                                          )
                                              internal
                                              pure
                                              returns (bytes32 result)
                                          {
                                              if (b.length < index + 32) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsThirtyTwoRequired,
                                                      b.length,
                                                      index + 32
                                                  ));
                                              }
                                              // Arrays are prefixed by a 256 bit length parameter
                                              index += 32;
                                              // Read the bytes32 from array memory
                                              assembly {
                                                  result := mload(add(b, index))
                                              }
                                              return result;
                                          }
                                          /// @dev Writes a bytes32 into a specific position in a byte array.
                                          /// @param b Byte array to insert <input> into.
                                          /// @param index Index in byte array of <input>.
                                          /// @param input bytes32 to put into byte array.
                                          function writeBytes32(
                                              bytes memory b,
                                              uint256 index,
                                              bytes32 input
                                          )
                                              internal
                                              pure
                                          {
                                              if (b.length < index + 32) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsThirtyTwoRequired,
                                                      b.length,
                                                      index + 32
                                                  ));
                                              }
                                              // Arrays are prefixed by a 256 bit length parameter
                                              index += 32;
                                              // Read the bytes32 from array memory
                                              assembly {
                                                  mstore(add(b, index), input)
                                              }
                                          }
                                          /// @dev Reads a uint256 value from a position in a byte array.
                                          /// @param b Byte array containing a uint256 value.
                                          /// @param index Index in byte array of uint256 value.
                                          /// @return result uint256 value from byte array.
                                          function readUint256(
                                              bytes memory b,
                                              uint256 index
                                          )
                                              internal
                                              pure
                                              returns (uint256 result)
                                          {
                                              result = uint256(readBytes32(b, index));
                                              return result;
                                          }
                                          /// @dev Writes a uint256 into a specific position in a byte array.
                                          /// @param b Byte array to insert <input> into.
                                          /// @param index Index in byte array of <input>.
                                          /// @param input uint256 to put into byte array.
                                          function writeUint256(
                                              bytes memory b,
                                              uint256 index,
                                              uint256 input
                                          )
                                              internal
                                              pure
                                          {
                                              writeBytes32(b, index, bytes32(input));
                                          }
                                          /// @dev Reads an unpadded bytes4 value from a position in a byte array.
                                          /// @param b Byte array containing a bytes4 value.
                                          /// @param index Index in byte array of bytes4 value.
                                          /// @return result bytes4 value from byte array.
                                          function readBytes4(
                                              bytes memory b,
                                              uint256 index
                                          )
                                              internal
                                              pure
                                              returns (bytes4 result)
                                          {
                                              if (b.length < index + 4) {
                                                  LibRichErrorsV06.rrevert(LibBytesRichErrorsV06.InvalidByteOperationError(
                                                      LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsFourRequired,
                                                      b.length,
                                                      index + 4
                                                  ));
                                              }
                                              // Arrays are prefixed by a 32 byte length field
                                              index += 32;
                                              // Read the bytes4 from array memory
                                              assembly {
                                                  result := mload(add(b, index))
                                                  // Solidity does not require us to clean the trailing bytes.
                                                  // We do it anyway
                                                  result := and(result, 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000)
                                              }
                                              return result;
                                          }
                                          /// @dev Writes a new length to a byte array.
                                          ///      Decreasing length will lead to removing the corresponding lower order bytes from the byte array.
                                          ///      Increasing length may lead to appending adjacent in-memory bytes to the end of the byte array.
                                          /// @param b Bytes array to write new length to.
                                          /// @param length New length of byte array.
                                          function writeLength(bytes memory b, uint256 length)
                                              internal
                                              pure
                                          {
                                              assembly {
                                                  mstore(b, length)
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibBytesRichErrorsV06 {
                                          enum InvalidByteOperationErrorCodes {
                                              FromLessThanOrEqualsToRequired,
                                              ToLessThanOrEqualsLengthRequired,
                                              LengthGreaterThanZeroRequired,
                                              LengthGreaterThanOrEqualsFourRequired,
                                              LengthGreaterThanOrEqualsTwentyRequired,
                                              LengthGreaterThanOrEqualsThirtyTwoRequired,
                                              LengthGreaterThanOrEqualsNestedBytesLengthRequired,
                                              DestinationLengthGreaterThanOrEqualSourceLengthRequired
                                          }
                                          // bytes4(keccak256("InvalidByteOperationError(uint8,uint256,uint256)"))
                                          bytes4 internal constant INVALID_BYTE_OPERATION_ERROR_SELECTOR =
                                              0x28006595;
                                          // solhint-disable func-name-mixedcase
                                          function InvalidByteOperationError(
                                              InvalidByteOperationErrorCodes errorCode,
                                              uint256 offset,
                                              uint256 required
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  INVALID_BYTE_OPERATION_ERROR_SELECTOR,
                                                  errorCode,
                                                  offset,
                                                  required
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibRichErrorsV06 {
                                          // bytes4(keccak256("Error(string)"))
                                          bytes4 internal constant STANDARD_ERROR_SELECTOR = 0x08c379a0;
                                          // solhint-disable func-name-mixedcase
                                          /// @dev ABI encode a standard, string revert error payload.
                                          ///      This is the same payload that would be included by a `revert(string)`
                                          ///      solidity statement. It has the function signature `Error(string)`.
                                          /// @param message The error string.
                                          /// @return The ABI encoded error.
                                          function StandardError(string memory message)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  STANDARD_ERROR_SELECTOR,
                                                  bytes(message)
                                              );
                                          }
                                          // solhint-enable func-name-mixedcase
                                          /// @dev Reverts an encoded rich revert reason `errorData`.
                                          /// @param errorData ABI encoded error data.
                                          function rrevert(bytes memory errorData)
                                              internal
                                              pure
                                          {
                                              assembly {
                                                  revert(add(errorData, 0x20), mload(errorData))
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibProxyRichErrors.sol";
                                      library LibBootstrap {
                                          /// @dev Magic bytes returned by the bootstrapper to indicate success.
                                          ///      This is `keccack('BOOTSTRAP_SUCCESS')`.
                                          bytes4 internal constant BOOTSTRAP_SUCCESS = 0xd150751b;
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev Perform a delegatecall and ensure it returns the magic bytes.
                                          /// @param target The call target.
                                          /// @param data The call data.
                                          function delegatecallBootstrapFunction(
                                              address target,
                                              bytes memory data
                                          )
                                              internal
                                          {
                                              (bool success, bytes memory resultData) = target.delegatecall(data);
                                              if (!success ||
                                                  resultData.length != 32 ||
                                                  abi.decode(resultData, (bytes4)) != BOOTSTRAP_SUCCESS)
                                              {
                                                  LibProxyRichErrors.BootstrapCallFailedError(target, resultData).rrevert();
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibProxyRichErrors {
                                          // solhint-disable func-name-mixedcase
                                          function NotImplementedError(bytes4 selector)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("NotImplementedError(bytes4)")),
                                                  selector
                                              );
                                          }
                                          function InvalidBootstrapCallerError(address actual, address expected)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InvalidBootstrapCallerError(address,address)")),
                                                  actual,
                                                  expected
                                              );
                                          }
                                          function InvalidDieCallerError(address actual, address expected)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InvalidDieCallerError(address,address)")),
                                                  actual,
                                                  expected
                                              );
                                          }
                                          function BootstrapCallFailedError(address target, bytes memory resultData)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("BootstrapCallFailedError(address,bytes)")),
                                                  target,
                                                  resultData
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../migrations/LibBootstrap.sol";
                                      import "../storage/LibProxyStorage.sol";
                                      import "./IBootstrap.sol";
                                      /// @dev Detachable `bootstrap()` feature.
                                      contract Bootstrap is
                                          IBootstrap
                                      {
                                          // solhint-disable state-visibility,indent
                                          /// @dev The ZeroEx contract.
                                          ///      This has to be immutable to persist across delegatecalls.
                                          address immutable private _deployer;
                                          /// @dev The implementation address of this contract.
                                          ///      This has to be immutable to persist across delegatecalls.
                                          address immutable private _implementation;
                                          /// @dev The deployer.
                                          ///      This has to be immutable to persist across delegatecalls.
                                          address immutable private _bootstrapCaller;
                                          // solhint-enable state-visibility,indent
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev Construct this contract and set the bootstrap migration contract.
                                          ///      After constructing this contract, `bootstrap()` should be called
                                          ///      to seed the initial feature set.
                                          /// @param bootstrapCaller The allowed caller of `bootstrap()`.
                                          constructor(address bootstrapCaller) public {
                                              _deployer = msg.sender;
                                              _implementation = address(this);
                                              _bootstrapCaller = bootstrapCaller;
                                          }
                                          /// @dev Bootstrap the initial feature set of this contract by delegatecalling
                                          ///      into `target`. Before exiting the `bootstrap()` function will
                                          ///      deregister itself from the proxy to prevent being called again.
                                          /// @param target The bootstrapper contract address.
                                          /// @param callData The call data to execute on `target`.
                                          function bootstrap(address target, bytes calldata callData) external override {
                                              // Only the bootstrap caller can call this function.
                                              if (msg.sender != _bootstrapCaller) {
                                                  LibProxyRichErrors.InvalidBootstrapCallerError(
                                                      msg.sender,
                                                      _bootstrapCaller
                                                  ).rrevert();
                                              }
                                              // Deregister.
                                              LibProxyStorage.getStorage().impls[this.bootstrap.selector] = address(0);
                                              // Self-destruct.
                                              Bootstrap(_implementation).die();
                                              // Call the bootstrapper.
                                              LibBootstrap.delegatecallBootstrapFunction(target, callData);
                                          }
                                          /// @dev Self-destructs this contract.
                                          ///      Can only be called by the deployer.
                                          function die() external {
                                              if (msg.sender != _deployer) {
                                                  LibProxyRichErrors.InvalidDieCallerError(msg.sender, _deployer).rrevert();
                                              }
                                              selfdestruct(msg.sender);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "./LibStorage.sol";
                                      /// @dev Storage helpers for the proxy contract.
                                      library LibProxyStorage {
                                          /// @dev Storage bucket for proxy contract.
                                          struct Storage {
                                              // Mapping of function selector -> function implementation
                                              mapping(bytes4 => address) impls;
                                              // The owner of the proxy contract.
                                              address owner;
                                          }
                                          /// @dev Get the storage bucket for this contract.
                                          function getStorage() internal pure returns (Storage storage stor) {
                                              uint256 storageSlot = LibStorage.getStorageSlot(
                                                  LibStorage.StorageId.Proxy
                                              );
                                              // Dip into assembly to change the slot pointed to by the local
                                              // variable `stor`.
                                              // See https://solidity.readthedocs.io/en/v0.6.8/assembly.html?highlight=slot#access-to-external-variables-functions-and-libraries
                                              assembly { stor_slot := storageSlot }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Common storage helpers
                                      library LibStorage {
                                          /// @dev What to bit-shift a storage ID by to get its slot.
                                          ///      This gives us a maximum of 2**128 inline fields in each bucket.
                                          uint256 private constant STORAGE_SLOT_EXP = 128;
                                          /// @dev Storage IDs for feature storage buckets.
                                          ///      WARNING: APPEND-ONLY.
                                          enum StorageId {
                                              Proxy,
                                              SimpleFunctionRegistry,
                                              Ownable,
                                              TokenSpender,
                                              TransformERC20
                                          }
                                          /// @dev Get the storage slot given a storage ID. We assign unique, well-spaced
                                          ///     slots to storage bucket variables to ensure they do not overlap.
                                          ///     See: https://solidity.readthedocs.io/en/v0.6.6/assembly.html#access-to-external-variables-functions-and-libraries
                                          /// @param storageId An entry in `StorageId`
                                          /// @return slot The storage slot.
                                          function getStorageSlot(StorageId storageId)
                                              internal
                                              pure
                                              returns (uint256 slot)
                                          {
                                              // This should never overflow with a reasonable `STORAGE_SLOT_EXP`
                                              // because Solidity will do a range check on `storageId` during the cast.
                                              return (uint256(storageId) + 1) << STORAGE_SLOT_EXP;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Detachable `bootstrap()` feature.
                                      interface IBootstrap {
                                          /// @dev Bootstrap the initial feature set of this contract by delegatecalling
                                          ///      into `target`. Before exiting the `bootstrap()` function will
                                          ///      deregister itself from the proxy to prevent being called again.
                                          /// @param target The bootstrapper contract address.
                                          /// @param callData The call data to execute on `target`.
                                          function bootstrap(address target, bytes calldata callData) external;
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibCommonRichErrors {
                                          // solhint-disable func-name-mixedcase
                                          function OnlyCallableBySelfError(address sender)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("OnlyCallableBySelfError(address)")),
                                                  sender
                                              );
                                          }
                                          function IllegalReentrancyError()
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("IllegalReentrancyError()"))
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibOwnableRichErrors {
                                          // solhint-disable func-name-mixedcase
                                          function OnlyOwnerError(
                                              address sender,
                                              address owner
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("OnlyOwnerError(address,address)")),
                                                  sender,
                                                  owner
                                              );
                                          }
                                          function TransferOwnerToZeroError()
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("TransferOwnerToZeroError()"))
                                              );
                                          }
                                          function MigrateCallFailedError(address target, bytes memory resultData)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("MigrateCallFailedError(address,bytes)")),
                                                  target,
                                                  resultData
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibSimpleFunctionRegistryRichErrors {
                                          // solhint-disable func-name-mixedcase
                                          function NotInRollbackHistoryError(bytes4 selector, address targetImpl)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("NotInRollbackHistoryError(bytes4,address)")),
                                                  selector,
                                                  targetImpl
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibSpenderRichErrors {
                                          // solhint-disable func-name-mixedcase
                                          function SpenderERC20TransferFromFailedError(
                                              address token,
                                              address owner,
                                              address to,
                                              uint256 amount,
                                              bytes memory errorData
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("SpenderERC20TransferFromFailedError(address,address,address,uint256,bytes)")),
                                                  token,
                                                  owner,
                                                  to,
                                                  amount,
                                                  errorData
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibTransformERC20RichErrors {
                                          // solhint-disable func-name-mixedcase,separate-by-one-line-in-contract
                                          function InsufficientEthAttachedError(
                                              uint256 ethAttached,
                                              uint256 ethNeeded
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InsufficientEthAttachedError(uint256,uint256)")),
                                                  ethAttached,
                                                  ethNeeded
                                              );
                                          }
                                          function IncompleteTransformERC20Error(
                                              address outputToken,
                                              uint256 outputTokenAmount,
                                              uint256 minOutputTokenAmount
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("IncompleteTransformERC20Error(address,uint256,uint256)")),
                                                  outputToken,
                                                  outputTokenAmount,
                                                  minOutputTokenAmount
                                              );
                                          }
                                          function NegativeTransformERC20OutputError(
                                              address outputToken,
                                              uint256 outputTokenLostAmount
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("NegativeTransformERC20OutputError(address,uint256)")),
                                                  outputToken,
                                                  outputTokenLostAmount
                                              );
                                          }
                                          function TransformerFailedError(
                                              address transformer,
                                              bytes memory transformerData,
                                              bytes memory resultData
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("TransformerFailedError(address,bytes,bytes)")),
                                                  transformer,
                                                  transformerData,
                                                  resultData
                                              );
                                          }
                                          // Common Transformer errors ///////////////////////////////////////////////
                                          function OnlyCallableByDeployerError(
                                              address caller,
                                              address deployer
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("OnlyCallableByDeployerError(address,address)")),
                                                  caller,
                                                  deployer
                                              );
                                          }
                                          function InvalidExecutionContextError(
                                              address actualContext,
                                              address expectedContext
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InvalidExecutionContextError(address,address)")),
                                                  actualContext,
                                                  expectedContext
                                              );
                                          }
                                          enum InvalidTransformDataErrorCode {
                                              INVALID_TOKENS,
                                              INVALID_ARRAY_LENGTH
                                          }
                                          function InvalidTransformDataError(
                                              InvalidTransformDataErrorCode errorCode,
                                              bytes memory transformData
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InvalidTransformDataError(uint8,bytes)")),
                                                  errorCode,
                                                  transformData
                                              );
                                          }
                                          // FillQuoteTransformer errors /////////////////////////////////////////////
                                          function IncompleteFillSellQuoteError(
                                              address sellToken,
                                              uint256 soldAmount,
                                              uint256 sellAmount
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("IncompleteFillSellQuoteError(address,uint256,uint256)")),
                                                  sellToken,
                                                  soldAmount,
                                                  sellAmount
                                              );
                                          }
                                          function IncompleteFillBuyQuoteError(
                                              address buyToken,
                                              uint256 boughtAmount,
                                              uint256 buyAmount
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("IncompleteFillBuyQuoteError(address,uint256,uint256)")),
                                                  buyToken,
                                                  boughtAmount,
                                                  buyAmount
                                              );
                                          }
                                          function InsufficientTakerTokenError(
                                              uint256 tokenBalance,
                                              uint256 tokensNeeded
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InsufficientTakerTokenError(uint256,uint256)")),
                                                  tokenBalance,
                                                  tokensNeeded
                                              );
                                          }
                                          function InsufficientProtocolFeeError(
                                              uint256 ethBalance,
                                              uint256 ethNeeded
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InsufficientProtocolFeeError(uint256,uint256)")),
                                                  ethBalance,
                                                  ethNeeded
                                              );
                                          }
                                          function InvalidERC20AssetDataError(
                                              bytes memory assetData
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InvalidERC20AssetDataError(bytes)")),
                                                  assetData
                                              );
                                          }
                                          function InvalidTakerFeeTokenError(
                                              address token
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("InvalidTakerFeeTokenError(address)")),
                                                  token
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibWalletRichErrors {
                                          // solhint-disable func-name-mixedcase
                                          function WalletExecuteCallFailedError(
                                              address wallet,
                                              address callTarget,
                                              bytes memory callData,
                                              uint256 callValue,
                                              bytes memory errorData
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("WalletExecuteCallFailedError(address,address,bytes,uint256,bytes)")),
                                                  wallet,
                                                  callTarget,
                                                  callData,
                                                  callValue,
                                                  errorData
                                              );
                                          }
                                          function WalletExecuteDelegateCallFailedError(
                                              address wallet,
                                              address callTarget,
                                              bytes memory callData,
                                              bytes memory errorData
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  bytes4(keccak256("WalletExecuteDelegateCallFailedError(address,address,bytes,bytes)")),
                                                  wallet,
                                                  callTarget,
                                                  callData,
                                                  errorData
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/AuthorizableV06.sol";
                                      import "../errors/LibSpenderRichErrors.sol";
                                      import "./IAllowanceTarget.sol";
                                      /// @dev The allowance target for the TokenSpender feature.
                                      contract AllowanceTarget is
                                          IAllowanceTarget,
                                          AuthorizableV06
                                      {
                                          // solhint-disable no-unused-vars,indent,no-empty-blocks
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev Execute an arbitrary call. Only an authority can call this.
                                          /// @param target The call target.
                                          /// @param callData The call data.
                                          /// @return resultData The data returned by the call.
                                          function executeCall(
                                              address payable target,
                                              bytes calldata callData
                                          )
                                              external
                                              override
                                              onlyAuthorized
                                              returns (bytes memory resultData)
                                          {
                                              bool success;
                                              (success, resultData) = target.call(callData);
                                              if (!success) {
                                                  resultData.rrevert();
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./interfaces/IAuthorizableV06.sol";
                                      import "./errors/LibRichErrorsV06.sol";
                                      import "./errors/LibAuthorizableRichErrorsV06.sol";
                                      import "./OwnableV06.sol";
                                      // solhint-disable no-empty-blocks
                                      contract AuthorizableV06 is
                                          OwnableV06,
                                          IAuthorizableV06
                                      {
                                          /// @dev Only authorized addresses can invoke functions with this modifier.
                                          modifier onlyAuthorized {
                                              _assertSenderIsAuthorized();
                                              _;
                                          }
                                          // @dev Whether an address is authorized to call privileged functions.
                                          // @param 0 Address to query.
                                          // @return 0 Whether the address is authorized.
                                          mapping (address => bool) public override authorized;
                                          // @dev Whether an address is authorized to call privileged functions.
                                          // @param 0 Index of authorized address.
                                          // @return 0 Authorized address.
                                          address[] public override authorities;
                                          /// @dev Initializes the `owner` address.
                                          constructor()
                                              public
                                              OwnableV06()
                                          {}
                                          /// @dev Authorizes an address.
                                          /// @param target Address to authorize.
                                          function addAuthorizedAddress(address target)
                                              external
                                              override
                                              onlyOwner
                                          {
                                              _addAuthorizedAddress(target);
                                          }
                                          /// @dev Removes authorizion of an address.
                                          /// @param target Address to remove authorization from.
                                          function removeAuthorizedAddress(address target)
                                              external
                                              override
                                              onlyOwner
                                          {
                                              if (!authorized[target]) {
                                                  LibRichErrorsV06.rrevert(LibAuthorizableRichErrorsV06.TargetNotAuthorizedError(target));
                                              }
                                              for (uint256 i = 0; i < authorities.length; i++) {
                                                  if (authorities[i] == target) {
                                                      _removeAuthorizedAddressAtIndex(target, i);
                                                      break;
                                                  }
                                              }
                                          }
                                          /// @dev Removes authorizion of an address.
                                          /// @param target Address to remove authorization from.
                                          /// @param index Index of target in authorities array.
                                          function removeAuthorizedAddressAtIndex(
                                              address target,
                                              uint256 index
                                          )
                                              external
                                              override
                                              onlyOwner
                                          {
                                              _removeAuthorizedAddressAtIndex(target, index);
                                          }
                                          /// @dev Gets all authorized addresses.
                                          /// @return Array of authorized addresses.
                                          function getAuthorizedAddresses()
                                              external
                                              override
                                              view
                                              returns (address[] memory)
                                          {
                                              return authorities;
                                          }
                                          /// @dev Reverts if msg.sender is not authorized.
                                          function _assertSenderIsAuthorized()
                                              internal
                                              view
                                          {
                                              if (!authorized[msg.sender]) {
                                                  LibRichErrorsV06.rrevert(LibAuthorizableRichErrorsV06.SenderNotAuthorizedError(msg.sender));
                                              }
                                          }
                                          /// @dev Authorizes an address.
                                          /// @param target Address to authorize.
                                          function _addAuthorizedAddress(address target)
                                              internal
                                          {
                                              // Ensure that the target is not the zero address.
                                              if (target == address(0)) {
                                                  LibRichErrorsV06.rrevert(LibAuthorizableRichErrorsV06.ZeroCantBeAuthorizedError());
                                              }
                                              // Ensure that the target is not already authorized.
                                              if (authorized[target]) {
                                                  LibRichErrorsV06.rrevert(LibAuthorizableRichErrorsV06.TargetAlreadyAuthorizedError(target));
                                              }
                                              authorized[target] = true;
                                              authorities.push(target);
                                              emit AuthorizedAddressAdded(target, msg.sender);
                                          }
                                          /// @dev Removes authorizion of an address.
                                          /// @param target Address to remove authorization from.
                                          /// @param index Index of target in authorities array.
                                          function _removeAuthorizedAddressAtIndex(
                                              address target,
                                              uint256 index
                                          )
                                              internal
                                          {
                                              if (!authorized[target]) {
                                                  LibRichErrorsV06.rrevert(LibAuthorizableRichErrorsV06.TargetNotAuthorizedError(target));
                                              }
                                              if (index >= authorities.length) {
                                                  LibRichErrorsV06.rrevert(LibAuthorizableRichErrorsV06.IndexOutOfBoundsError(
                                                      index,
                                                      authorities.length
                                                  ));
                                              }
                                              if (authorities[index] != target) {
                                                  LibRichErrorsV06.rrevert(LibAuthorizableRichErrorsV06.AuthorizedAddressMismatchError(
                                                      authorities[index],
                                                      target
                                                  ));
                                              }
                                              delete authorized[target];
                                              authorities[index] = authorities[authorities.length - 1];
                                              authorities.pop();
                                              emit AuthorizedAddressRemoved(target, msg.sender);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./IOwnableV06.sol";
                                      interface IAuthorizableV06 is
                                          IOwnableV06
                                      {
                                          // Event logged when a new address is authorized.
                                          event AuthorizedAddressAdded(
                                              address indexed target,
                                              address indexed caller
                                          );
                                          // Event logged when a currently authorized address is unauthorized.
                                          event AuthorizedAddressRemoved(
                                              address indexed target,
                                              address indexed caller
                                          );
                                          /// @dev Authorizes an address.
                                          /// @param target Address to authorize.
                                          function addAuthorizedAddress(address target)
                                              external;
                                          /// @dev Removes authorizion of an address.
                                          /// @param target Address to remove authorization from.
                                          function removeAuthorizedAddress(address target)
                                              external;
                                          /// @dev Removes authorizion of an address.
                                          /// @param target Address to remove authorization from.
                                          /// @param index Index of target in authorities array.
                                          function removeAuthorizedAddressAtIndex(
                                              address target,
                                              uint256 index
                                          )
                                              external;
                                          /// @dev Gets all authorized addresses.
                                          /// @return authorizedAddresses Array of authorized addresses.
                                          function getAuthorizedAddresses()
                                              external
                                              view
                                              returns (address[] memory authorizedAddresses);
                                          /// @dev Whether an adderss is authorized to call privileged functions.
                                          /// @param addr Address to query.
                                          /// @return isAuthorized Whether the address is authorized.
                                          function authorized(address addr) external view returns (bool isAuthorized);
                                          /// @dev All addresseses authorized to call privileged functions.
                                          /// @param idx Index of authorized address.
                                          /// @return addr Authorized address.
                                          function authorities(uint256 idx) external view returns (address addr);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      interface IOwnableV06 {
                                          /// @dev Emitted by Ownable when ownership is transferred.
                                          /// @param previousOwner The previous owner of the contract.
                                          /// @param newOwner The new owner of the contract.
                                          event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
                                          /// @dev Transfers ownership of the contract to a new address.
                                          /// @param newOwner The address that will become the owner.
                                          function transferOwnership(address newOwner) external;
                                          /// @dev The owner of this contract.
                                          /// @return ownerAddress The owner address.
                                          function owner() external view returns (address ownerAddress);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibAuthorizableRichErrorsV06 {
                                          // bytes4(keccak256("AuthorizedAddressMismatchError(address,address)"))
                                          bytes4 internal constant AUTHORIZED_ADDRESS_MISMATCH_ERROR_SELECTOR =
                                              0x140a84db;
                                          // bytes4(keccak256("IndexOutOfBoundsError(uint256,uint256)"))
                                          bytes4 internal constant INDEX_OUT_OF_BOUNDS_ERROR_SELECTOR =
                                              0xe9f83771;
                                          // bytes4(keccak256("SenderNotAuthorizedError(address)"))
                                          bytes4 internal constant SENDER_NOT_AUTHORIZED_ERROR_SELECTOR =
                                              0xb65a25b9;
                                          // bytes4(keccak256("TargetAlreadyAuthorizedError(address)"))
                                          bytes4 internal constant TARGET_ALREADY_AUTHORIZED_ERROR_SELECTOR =
                                              0xde16f1a0;
                                          // bytes4(keccak256("TargetNotAuthorizedError(address)"))
                                          bytes4 internal constant TARGET_NOT_AUTHORIZED_ERROR_SELECTOR =
                                              0xeb5108a2;
                                          // bytes4(keccak256("ZeroCantBeAuthorizedError()"))
                                          bytes internal constant ZERO_CANT_BE_AUTHORIZED_ERROR_BYTES =
                                              hex"57654fe4";
                                          // solhint-disable func-name-mixedcase
                                          function AuthorizedAddressMismatchError(
                                              address authorized,
                                              address target
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  AUTHORIZED_ADDRESS_MISMATCH_ERROR_SELECTOR,
                                                  authorized,
                                                  target
                                              );
                                          }
                                          function IndexOutOfBoundsError(
                                              uint256 index,
                                              uint256 length
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  INDEX_OUT_OF_BOUNDS_ERROR_SELECTOR,
                                                  index,
                                                  length
                                              );
                                          }
                                          function SenderNotAuthorizedError(address sender)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  SENDER_NOT_AUTHORIZED_ERROR_SELECTOR,
                                                  sender
                                              );
                                          }
                                          function TargetAlreadyAuthorizedError(address target)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  TARGET_ALREADY_AUTHORIZED_ERROR_SELECTOR,
                                                  target
                                              );
                                          }
                                          function TargetNotAuthorizedError(address target)
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  TARGET_NOT_AUTHORIZED_ERROR_SELECTOR,
                                                  target
                                              );
                                          }
                                          function ZeroCantBeAuthorizedError()
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return ZERO_CANT_BE_AUTHORIZED_ERROR_BYTES;
                                          }
                                      }
                                      /*
                                        Copyright 2019 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./interfaces/IOwnableV06.sol";
                                      import "./errors/LibRichErrorsV06.sol";
                                      import "./errors/LibOwnableRichErrorsV06.sol";
                                      contract OwnableV06 is
                                          IOwnableV06
                                      {
                                          /// @dev The owner of this contract.
                                          /// @return 0 The owner address.
                                          address public override owner;
                                          constructor() public {
                                              owner = msg.sender;
                                          }
                                          modifier onlyOwner() {
                                              _assertSenderIsOwner();
                                              _;
                                          }
                                          /// @dev Change the owner of this contract.
                                          /// @param newOwner New owner address.
                                          function transferOwnership(address newOwner)
                                              public
                                              override
                                              onlyOwner
                                          {
                                              if (newOwner == address(0)) {
                                                  LibRichErrorsV06.rrevert(LibOwnableRichErrorsV06.TransferOwnerToZeroError());
                                              } else {
                                                  owner = newOwner;
                                                  emit OwnershipTransferred(msg.sender, newOwner);
                                              }
                                          }
                                          function _assertSenderIsOwner()
                                              internal
                                              view
                                          {
                                              if (msg.sender != owner) {
                                                  LibRichErrorsV06.rrevert(LibOwnableRichErrorsV06.OnlyOwnerError(
                                                      msg.sender,
                                                      owner
                                                  ));
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibOwnableRichErrorsV06 {
                                          // bytes4(keccak256("OnlyOwnerError(address,address)"))
                                          bytes4 internal constant ONLY_OWNER_ERROR_SELECTOR =
                                              0x1de45ad1;
                                          // bytes4(keccak256("TransferOwnerToZeroError()"))
                                          bytes internal constant TRANSFER_OWNER_TO_ZERO_ERROR_BYTES =
                                              hex"e69edc3e";
                                          // solhint-disable func-name-mixedcase
                                          function OnlyOwnerError(
                                              address sender,
                                              address owner
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  ONLY_OWNER_ERROR_SELECTOR,
                                                  sender,
                                                  owner
                                              );
                                          }
                                          function TransferOwnerToZeroError()
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return TRANSFER_OWNER_TO_ZERO_ERROR_BYTES;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/interfaces/IAuthorizableV06.sol";
                                      /// @dev The allowance target for the TokenSpender feature.
                                      interface IAllowanceTarget is
                                          IAuthorizableV06
                                      {
                                          /// @dev Execute an arbitrary call. Only an authority can call this.
                                          /// @param target The call target.
                                          /// @param callData The call data.
                                          /// @return resultData The data returned by the call.
                                          function executeCall(
                                              address payable target,
                                              bytes calldata callData
                                          )
                                              external
                                              returns (bytes memory resultData);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibOwnableRichErrorsV06.sol";
                                      import "../errors/LibWalletRichErrors.sol";
                                      import "./IFlashWallet.sol";
                                      /// @dev A contract that can execute arbitrary calls from its owner.
                                      contract FlashWallet is
                                          IFlashWallet
                                      {
                                          // solhint-disable no-unused-vars,indent,no-empty-blocks
                                          using LibRichErrorsV06 for bytes;
                                          // solhint-disable
                                          /// @dev Store the owner/deployer as an immutable to make this contract stateless.
                                          address public override immutable owner;
                                          // solhint-enable
                                          constructor() public {
                                              // The deployer is the owner.
                                              owner = msg.sender;
                                          }
                                          /// @dev Allows only the (immutable) owner to call a function.
                                          modifier onlyOwner() virtual {
                                              if (msg.sender != owner) {
                                                  LibOwnableRichErrorsV06.OnlyOwnerError(
                                                      msg.sender,
                                                      owner
                                                  ).rrevert();
                                              }
                                              _;
                                          }
                                          /// @dev Execute an arbitrary call. Only an authority can call this.
                                          /// @param target The call target.
                                          /// @param callData The call data.
                                          /// @param value Ether to attach to the call.
                                          /// @return resultData The data returned by the call.
                                          function executeCall(
                                              address payable target,
                                              bytes calldata callData,
                                              uint256 value
                                          )
                                              external
                                              payable
                                              override
                                              onlyOwner
                                              returns (bytes memory resultData)
                                          {
                                              bool success;
                                              (success, resultData) = target.call{value: value}(callData);
                                              if (!success) {
                                                  LibWalletRichErrors
                                                      .WalletExecuteCallFailedError(
                                                          address(this),
                                                          target,
                                                          callData,
                                                          value,
                                                          resultData
                                                      )
                                                      .rrevert();
                                              }
                                          }
                                          /// @dev Execute an arbitrary delegatecall, in the context of this puppet.
                                          ///      Only an authority can call this.
                                          /// @param target The call target.
                                          /// @param callData The call data.
                                          /// @return resultData The data returned by the call.
                                          function executeDelegateCall(
                                              address payable target,
                                              bytes calldata callData
                                          )
                                              external
                                              payable
                                              override
                                              onlyOwner
                                              returns (bytes memory resultData)
                                          {
                                              bool success;
                                              (success, resultData) = target.delegatecall(callData);
                                              if (!success) {
                                                  LibWalletRichErrors
                                                      .WalletExecuteDelegateCallFailedError(
                                                          address(this),
                                                          target,
                                                          callData,
                                                          resultData
                                                      )
                                                      .rrevert();
                                              }
                                          }
                                          // solhint-disable
                                          /// @dev Allows this contract to receive ether.
                                          receive() external override payable {}
                                          // solhint-enable
                                          /// @dev Signal support for receiving ERC1155 tokens.
                                          /// @param interfaceID The interface ID, as per ERC-165 rules.
                                          /// @return hasSupport `true` if this contract supports an ERC-165 interface.
                                          function supportsInterface(bytes4 interfaceID)
                                              external
                                              pure
                                              returns (bool hasSupport)
                                          {
                                              return  interfaceID == this.supportsInterface.selector ||
                                                      interfaceID == this.onERC1155Received.selector ^ this.onERC1155BatchReceived.selector ||
                                                      interfaceID == this.tokenFallback.selector;
                                          }
                                          ///  @dev Allow this contract to receive ERC1155 tokens.
                                          ///  @return success  `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
                                          function onERC1155Received(
                                              address, // operator,
                                              address, // from,
                                              uint256, // id,
                                              uint256, // value,
                                              bytes calldata //data
                                          )
                                              external
                                              pure
                                              returns (bytes4 success)
                                          {
                                              return this.onERC1155Received.selector;
                                          }
                                          ///  @dev Allow this contract to receive ERC1155 tokens.
                                          ///  @return success  `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
                                          function onERC1155BatchReceived(
                                              address, // operator,
                                              address, // from,
                                              uint256[] calldata, // ids,
                                              uint256[] calldata, // values,
                                              bytes calldata // data
                                          )
                                              external
                                              pure
                                              returns (bytes4 success)
                                          {
                                              return this.onERC1155BatchReceived.selector;
                                          }
                                          /// @dev Allows this contract to receive ERC223 tokens.
                                          function tokenFallback(
                                              address, // from,
                                              uint256, // value,
                                              bytes calldata // value
                                          )
                                              external
                                              pure
                                          {}
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/interfaces/IOwnableV06.sol";
                                      /// @dev A contract that can execute arbitrary calls from its owner.
                                      interface IFlashWallet {
                                          /// @dev Execute an arbitrary call. Only an authority can call this.
                                          /// @param target The call target.
                                          /// @param callData The call data.
                                          /// @param value Ether to attach to the call.
                                          /// @return resultData The data returned by the call.
                                          function executeCall(
                                              address payable target,
                                              bytes calldata callData,
                                              uint256 value
                                          )
                                              external
                                              payable
                                              returns (bytes memory resultData);
                                          /// @dev Execute an arbitrary delegatecall, in the context of this puppet.
                                          ///      Only an authority can call this.
                                          /// @param target The call target.
                                          /// @param callData The call data.
                                          /// @return resultData The data returned by the call.
                                          function executeDelegateCall(
                                              address payable target,
                                              bytes calldata callData
                                          )
                                              external
                                              payable
                                              returns (bytes memory resultData);
                                          /// @dev Allows the puppet to receive ETH.
                                          receive() external payable;
                                          /// @dev Fetch the immutable owner/deployer of this contract.
                                          /// @return owner_ The immutable owner/deployer/
                                          function owner() external view returns (address owner_);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/AuthorizableV06.sol";
                                      /// @dev A contract with a `die()` function.
                                      interface IKillable {
                                          function die() external;
                                      }
                                      /// @dev Deployer contract for ERC20 transformers.
                                      ///      Only authorities may call `deploy()` and `kill()`.
                                      contract TransformerDeployer is
                                          AuthorizableV06
                                      {
                                          /// @dev Emitted when a contract is deployed via `deploy()`.
                                          /// @param deployedAddress The address of the deployed contract.
                                          /// @param nonce The deployment nonce.
                                          /// @param sender The caller of `deploy()`.
                                          event Deployed(address deployedAddress, uint256 nonce, address sender);
                                          /// @dev Emitted when a contract is killed via `kill()`.
                                          /// @param target The address of the contract being killed..
                                          /// @param sender The caller of `kill()`.
                                          event Killed(address target, address sender);
                                          // @dev The current nonce of this contract.
                                          uint256 public nonce = 1;
                                          // @dev Mapping of deployed contract address to deployment nonce.
                                          mapping (address => uint256) public toDeploymentNonce;
                                          /// @dev Create this contract and register authorities.
                                          constructor(address[] memory authorities) public {
                                              for (uint256 i = 0; i < authorities.length; ++i) {
                                                  _addAuthorizedAddress(authorities[i]);
                                              }
                                          }
                                          /// @dev Deploy a new contract. Only callable by an authority.
                                          ///      Any attached ETH will also be forwarded.
                                          function deploy(bytes memory bytecode)
                                              public
                                              payable
                                              onlyAuthorized
                                              returns (address deployedAddress)
                                          {
                                              uint256 deploymentNonce = nonce;
                                              nonce += 1;
                                              assembly {
                                                  deployedAddress := create(callvalue(), add(bytecode, 32), mload(bytecode))
                                              }
                                              toDeploymentNonce[deployedAddress] = deploymentNonce;
                                              emit Deployed(deployedAddress, deploymentNonce, msg.sender);
                                          }
                                          /// @dev Call `die()` on a contract. Only callable by an authority.
                                          function kill(IKillable target)
                                              public
                                              onlyAuthorized
                                          {
                                              target.die();
                                              emit Killed(address(target), msg.sender);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Basic interface for a feature contract.
                                      interface IFeature {
                                          // solhint-disable func-name-mixedcase
                                          /// @dev The name of this feature set.
                                          function FEATURE_NAME() external view returns (string memory name);
                                          /// @dev The version of this feature set.
                                          function FEATURE_VERSION() external view returns (uint256 version);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/interfaces/IOwnableV06.sol";
                                      // solhint-disable no-empty-blocks
                                      /// @dev Owner management and migration features.
                                      interface IOwnable is
                                          IOwnableV06
                                      {
                                          /// @dev Emitted when `migrate()` is called.
                                          /// @param caller The caller of `migrate()`.
                                          /// @param migrator The migration contract.
                                          /// @param newOwner The address of the new owner.
                                          event Migrated(address caller, address migrator, address newOwner);
                                          /// @dev Execute a migration function in the context of the ZeroEx contract.
                                          ///      The result of the function being called should be the magic bytes
                                          ///      0x2c64c5ef (`keccack('MIGRATE_SUCCESS')`). Only callable by the owner.
                                          ///      The owner will be temporarily set to `address(this)` inside the call.
                                          ///      Before returning, the owner will be set to `newOwner`.
                                          /// @param target The migrator contract address.
                                          /// @param newOwner The address of the new owner.
                                          /// @param data The call data.
                                          function migrate(address target, bytes calldata data, address newOwner) external;
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Basic registry management features.
                                      interface ISimpleFunctionRegistry {
                                          /// @dev A function implementation was updated via `extend()` or `rollback()`.
                                          /// @param selector The function selector.
                                          /// @param oldImpl The implementation contract address being replaced.
                                          /// @param newImpl The replacement implementation contract address.
                                          event ProxyFunctionUpdated(bytes4 indexed selector, address oldImpl, address newImpl);
                                          /// @dev Roll back to a prior implementation of a function.
                                          /// @param selector The function selector.
                                          /// @param targetImpl The address of an older implementation of the function.
                                          function rollback(bytes4 selector, address targetImpl) external;
                                          /// @dev Register or replace a function.
                                          /// @param selector The function selector.
                                          /// @param impl The implementation contract for the function.
                                          function extend(bytes4 selector, address impl) external;
                                          /// @dev Retrieve the length of the rollback history for a function.
                                          /// @param selector The function selector.
                                          /// @return rollbackLength The number of items in the rollback history for
                                          ///         the function.
                                          function getRollbackLength(bytes4 selector)
                                              external
                                              view
                                              returns (uint256 rollbackLength);
                                          /// @dev Retrieve an entry in the rollback history for a function.
                                          /// @param selector The function selector.
                                          /// @param idx The index in the rollback history.
                                          /// @return impl An implementation address for the function at
                                          ///         index `idx`.
                                          function getRollbackEntryAtIndex(bytes4 selector, uint256 idx)
                                              external
                                              view
                                              returns (address impl);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      /// @dev Feature that allows spending token allowances.
                                      interface ITokenSpender {
                                          /// @dev Transfers ERC20 tokens from `owner` to `to`.
                                          ///      Only callable from within.
                                          /// @param token The token to spend.
                                          /// @param owner The owner of the tokens.
                                          /// @param to The recipient of the tokens.
                                          /// @param amount The amount of `token` to transfer.
                                          function _spendERC20Tokens(
                                              IERC20TokenV06 token,
                                              address owner,
                                              address to,
                                              uint256 amount
                                          )
                                              external;
                                          /// @dev Gets the maximum amount of an ERC20 token `token` that can be
                                          ///      pulled from `owner`.
                                          /// @param token The token to spend.
                                          /// @param owner The owner of the tokens.
                                          /// @return amount The amount of tokens that can be pulled.
                                          function getSpendableERC20BalanceOf(IERC20TokenV06 token, address owner)
                                              external
                                              view
                                              returns (uint256 amount);
                                          /// @dev Get the address of the allowance target.
                                          /// @return target The target of token allowances.
                                          function getAllowanceTarget() external view returns (address target);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      interface IERC20TokenV06 {
                                          // solhint-disable no-simple-event-func-name
                                          event Transfer(
                                              address indexed from,
                                              address indexed to,
                                              uint256 value
                                          );
                                          event Approval(
                                              address indexed owner,
                                              address indexed spender,
                                              uint256 value
                                          );
                                          /// @dev send `value` token to `to` from `msg.sender`
                                          /// @param to The address of the recipient
                                          /// @param value The amount of token to be transferred
                                          /// @return True if transfer was successful
                                          function transfer(address to, uint256 value)
                                              external
                                              returns (bool);
                                          /// @dev send `value` token to `to` from `from` on the condition it is approved by `from`
                                          /// @param from The address of the sender
                                          /// @param to The address of the recipient
                                          /// @param value The amount of token to be transferred
                                          /// @return True if transfer was successful
                                          function transferFrom(
                                              address from,
                                              address to,
                                              uint256 value
                                          )
                                              external
                                              returns (bool);
                                          /// @dev `msg.sender` approves `spender` to spend `value` tokens
                                          /// @param spender The address of the account able to transfer the tokens
                                          /// @param value The amount of wei to be approved for transfer
                                          /// @return Always true if the call has enough gas to complete execution
                                          function approve(address spender, uint256 value)
                                              external
                                              returns (bool);
                                          /// @dev Query total supply of token
                                          /// @return Total supply of token
                                          function totalSupply()
                                              external
                                              view
                                              returns (uint256);
                                          /// @dev Get the balance of `owner`.
                                          /// @param owner The address from which the balance will be retrieved
                                          /// @return Balance of owner
                                          function balanceOf(address owner)
                                              external
                                              view
                                              returns (uint256);
                                          /// @dev Get the allowance for `spender` to spend from `owner`.
                                          /// @param owner The address of the account owning tokens
                                          /// @param spender The address of the account able to transfer the tokens
                                          /// @return Amount of remaining tokens allowed to spent
                                          function allowance(address owner, address spender)
                                              external
                                              view
                                              returns (uint256);
                                          /// @dev Get the number of decimals this token has.
                                          function decimals()
                                              external
                                              view
                                              returns (uint8);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "../transformers/IERC20Transformer.sol";
                                      import "../external/IFlashWallet.sol";
                                      /// @dev Feature to composably transform between ERC20 tokens.
                                      interface ITransformERC20 {
                                          /// @dev Defines a transformation to run in `transformERC20()`.
                                          struct Transformation {
                                              // The deployment nonce for the transformer.
                                              // The address of the transformer contract will be derived from this
                                              // value.
                                              uint32 deploymentNonce;
                                              // Arbitrary data to pass to the transformer.
                                              bytes data;
                                          }
                                          /// @dev Raised upon a successful `transformERC20`.
                                          /// @param taker The taker (caller) address.
                                          /// @param inputToken The token being provided by the taker.
                                          ///        If `0xeee...`, ETH is implied and should be provided with the call.`
                                          /// @param outputToken The token to be acquired by the taker.
                                          ///        `0xeee...` implies ETH.
                                          /// @param inputTokenAmount The amount of `inputToken` to take from the taker.
                                          /// @param outputTokenAmount The amount of `outputToken` received by the taker.
                                          event TransformedERC20(
                                              address indexed taker,
                                              address inputToken,
                                              address outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 outputTokenAmount
                                          );
                                          /// @dev Raised when `setTransformerDeployer()` is called.
                                          /// @param transformerDeployer The new deployer address.
                                          event TransformerDeployerUpdated(address transformerDeployer);
                                          /// @dev Replace the allowed deployer for transformers.
                                          ///      Only callable by the owner.
                                          /// @param transformerDeployer The address of the trusted deployer for transformers.
                                          function setTransformerDeployer(address transformerDeployer)
                                              external;
                                          /// @dev Deploy a new flash wallet instance and replace the current one with it.
                                          ///      Useful if we somehow break the current wallet instance.
                                          ///      Anyone can call this.
                                          /// @return wallet The new wallet instance.
                                          function createTransformWallet()
                                              external
                                              returns (IFlashWallet wallet);
                                          /// @dev Executes a series of transformations to convert an ERC20 `inputToken`
                                          ///      to an ERC20 `outputToken`.
                                          /// @param inputToken The token being provided by the sender.
                                          ///        If `0xeee...`, ETH is implied and should be provided with the call.`
                                          /// @param outputToken The token to be acquired by the sender.
                                          ///        `0xeee...` implies ETH.
                                          /// @param inputTokenAmount The amount of `inputToken` to take from the sender.
                                          /// @param minOutputTokenAmount The minimum amount of `outputToken` the sender
                                          ///        must receive for the entire transformation to succeed.
                                          /// @param transformations The transformations to execute on the token balance(s)
                                          ///        in sequence.
                                          /// @return outputTokenAmount The amount of `outputToken` received by the sender.
                                          function transformERC20(
                                              IERC20TokenV06 inputToken,
                                              IERC20TokenV06 outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 minOutputTokenAmount,
                                              Transformation[] calldata transformations
                                          )
                                              external
                                              payable
                                              returns (uint256 outputTokenAmount);
                                          /// @dev Internal version of `transformERC20()`. Only callable from within.
                                          /// @param callDataHash Hash of the ingress calldata.
                                          /// @param taker The taker address.
                                          /// @param inputToken The token being provided by the taker.
                                          ///        If `0xeee...`, ETH is implied and should be provided with the call.`
                                          /// @param outputToken The token to be acquired by the taker.
                                          ///        `0xeee...` implies ETH.
                                          /// @param inputTokenAmount The amount of `inputToken` to take from the taker.
                                          /// @param minOutputTokenAmount The minimum amount of `outputToken` the taker
                                          ///        must receive for the entire transformation to succeed.
                                          /// @param transformations The transformations to execute on the token balance(s)
                                          ///        in sequence.
                                          /// @return outputTokenAmount The amount of `outputToken` received by the taker.
                                          function _transformERC20(
                                              bytes32 callDataHash,
                                              address payable taker,
                                              IERC20TokenV06 inputToken,
                                              IERC20TokenV06 outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 minOutputTokenAmount,
                                              Transformation[] calldata transformations
                                          )
                                              external
                                              payable
                                              returns (uint256 outputTokenAmount);
                                          /// @dev Return the current wallet instance that will serve as the execution
                                          ///      context for transformations.
                                          /// @return wallet The wallet instance.
                                          function getTransformWallet()
                                              external
                                              view
                                              returns (IFlashWallet wallet);
                                          /// @dev Return the allowed deployer for transformers.
                                          /// @return deployer The transform deployer address.
                                          function getTransformerDeployer()
                                              external
                                              view
                                              returns (address deployer);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      /// @dev A transformation callback used in `TransformERC20.transformERC20()`.
                                      interface IERC20Transformer {
                                          /// @dev Called from `TransformERC20.transformERC20()`. This will be
                                          ///      delegatecalled in the context of the FlashWallet instance being used.
                                          /// @param callDataHash The hash of the `TransformERC20.transformERC20()` calldata.
                                          /// @param taker The taker address (caller of `TransformERC20.transformERC20()`).
                                          /// @param data Arbitrary data to pass to the transformer.
                                          /// @return success The success bytes (`LibERC20Transformer.TRANSFORMER_SUCCESS`).
                                          function transform(
                                              bytes32 callDataHash,
                                              address payable taker,
                                              bytes calldata data
                                          )
                                              external
                                              returns (bytes4 success);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../fixins/FixinCommon.sol";
                                      import "../errors/LibOwnableRichErrors.sol";
                                      import "../storage/LibOwnableStorage.sol";
                                      import "../migrations/LibBootstrap.sol";
                                      import "../migrations/LibMigrate.sol";
                                      import "./IFeature.sol";
                                      import "./IOwnable.sol";
                                      import "./SimpleFunctionRegistry.sol";
                                      /// @dev Owner management features.
                                      contract Ownable is
                                          IFeature,
                                          IOwnable,
                                          FixinCommon
                                      {
                                          // solhint-disable
                                          /// @dev Name of this feature.
                                          string public constant override FEATURE_NAME = "Ownable";
                                          /// @dev Version of this feature.
                                          uint256 public immutable override FEATURE_VERSION = _encodeVersion(1, 0, 0);
                                          /// @dev The deployed address of this contract.
                                          address immutable private _implementation;
                                          // solhint-enable
                                          using LibRichErrorsV06 for bytes;
                                          constructor() public {
                                              _implementation = address(this);
                                          }
                                          /// @dev Initializes this feature. The intial owner will be set to this (ZeroEx)
                                          ///      to allow the bootstrappers to call `extend()`. Ownership should be
                                          ///      transferred to the real owner by the bootstrapper after
                                          ///      bootstrapping is complete.
                                          /// @return success Magic bytes if successful.
                                          function bootstrap() external returns (bytes4 success) {
                                              // Set the owner to ourselves to allow bootstrappers to call `extend()`.
                                              LibOwnableStorage.getStorage().owner = address(this);
                                              // Register feature functions.
                                              SimpleFunctionRegistry(address(this))._extendSelf(this.transferOwnership.selector, _implementation);
                                              SimpleFunctionRegistry(address(this))._extendSelf(this.owner.selector, _implementation);
                                              SimpleFunctionRegistry(address(this))._extendSelf(this.migrate.selector, _implementation);
                                              return LibBootstrap.BOOTSTRAP_SUCCESS;
                                          }
                                          /// @dev Change the owner of this contract.
                                          ///      Only directly callable by the owner.
                                          /// @param newOwner New owner address.
                                          function transferOwnership(address newOwner)
                                              external
                                              override
                                              onlyOwner
                                          {
                                              LibOwnableStorage.Storage storage proxyStor = LibOwnableStorage.getStorage();
                                              if (newOwner == address(0)) {
                                                  LibOwnableRichErrors.TransferOwnerToZeroError().rrevert();
                                              } else {
                                                  proxyStor.owner = newOwner;
                                                  emit OwnershipTransferred(msg.sender, newOwner);
                                              }
                                          }
                                          /// @dev Execute a migration function in the context of the ZeroEx contract.
                                          ///      The result of the function being called should be the magic bytes
                                          ///      0x2c64c5ef (`keccack('MIGRATE_SUCCESS')`). Only callable by the owner.
                                          ///      Temporarily sets the owner to ourselves so we can perform admin functions.
                                          ///      Before returning, the owner will be set to `newOwner`.
                                          /// @param target The migrator contract address.
                                          /// @param data The call data.
                                          /// @param newOwner The address of the new owner.
                                          function migrate(address target, bytes calldata data, address newOwner)
                                              external
                                              override
                                              onlyOwner
                                          {
                                              if (newOwner == address(0)) {
                                                  LibOwnableRichErrors.TransferOwnerToZeroError().rrevert();
                                              }
                                              LibOwnableStorage.Storage storage stor = LibOwnableStorage.getStorage();
                                              // The owner will be temporarily set to `address(this)` inside the call.
                                              stor.owner = address(this);
                                              // Perform the migration.
                                              LibMigrate.delegatecallMigrateFunction(target, data);
                                              // Update the owner.
                                              stor.owner = newOwner;
                                              emit Migrated(msg.sender, target, newOwner);
                                          }
                                          /// @dev Get the owner of this contract.
                                          /// @return owner_ The owner of this contract.
                                          function owner() external override view returns (address owner_) {
                                              return LibOwnableStorage.getStorage().owner;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibCommonRichErrors.sol";
                                      import "../errors/LibOwnableRichErrors.sol";
                                      import "../features/IOwnable.sol";
                                      /// @dev Common feature utilities.
                                      contract FixinCommon {
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev The caller must be this contract.
                                          modifier onlySelf() virtual {
                                              if (msg.sender != address(this)) {
                                                  LibCommonRichErrors.OnlyCallableBySelfError(msg.sender).rrevert();
                                              }
                                              _;
                                          }
                                          /// @dev The caller of this function must be the owner.
                                          modifier onlyOwner() virtual {
                                              {
                                                  address owner = IOwnable(address(this)).owner();
                                                  if (msg.sender != owner) {
                                                      LibOwnableRichErrors.OnlyOwnerError(
                                                          msg.sender,
                                                          owner
                                                      ).rrevert();
                                                  }
                                              }
                                              _;
                                          }
                                          /// @dev Encode a feature version as a `uint256`.
                                          /// @param major The major version number of the feature.
                                          /// @param minor The minor version number of the feature.
                                          /// @param revision The revision number of the feature.
                                          /// @return encodedVersion The encoded version number.
                                          function _encodeVersion(uint32 major, uint32 minor, uint32 revision)
                                              internal
                                              pure
                                              returns (uint256 encodedVersion)
                                          {
                                              return (major << 64) | (minor << 32) | revision;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "./LibStorage.sol";
                                      /// @dev Storage helpers for the `Ownable` feature.
                                      library LibOwnableStorage {
                                          /// @dev Storage bucket for this feature.
                                          struct Storage {
                                              // The owner of this contract.
                                              address owner;
                                          }
                                          /// @dev Get the storage bucket for this contract.
                                          function getStorage() internal pure returns (Storage storage stor) {
                                              uint256 storageSlot = LibStorage.getStorageSlot(
                                                  LibStorage.StorageId.Ownable
                                              );
                                              // Dip into assembly to change the slot pointed to by the local
                                              // variable `stor`.
                                              // See https://solidity.readthedocs.io/en/v0.6.8/assembly.html?highlight=slot#access-to-external-variables-functions-and-libraries
                                              assembly { stor_slot := storageSlot }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibOwnableRichErrors.sol";
                                      library LibMigrate {
                                          /// @dev Magic bytes returned by a migrator to indicate success.
                                          ///      This is `keccack('MIGRATE_SUCCESS')`.
                                          bytes4 internal constant MIGRATE_SUCCESS = 0x2c64c5ef;
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev Perform a delegatecall and ensure it returns the magic bytes.
                                          /// @param target The call target.
                                          /// @param data The call data.
                                          function delegatecallMigrateFunction(
                                              address target,
                                              bytes memory data
                                          )
                                              internal
                                          {
                                              (bool success, bytes memory resultData) = target.delegatecall(data);
                                              if (!success ||
                                                  resultData.length != 32 ||
                                                  abi.decode(resultData, (bytes4)) != MIGRATE_SUCCESS)
                                              {
                                                  LibOwnableRichErrors.MigrateCallFailedError(target, resultData).rrevert();
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../fixins/FixinCommon.sol";
                                      import "../storage/LibProxyStorage.sol";
                                      import "../storage/LibSimpleFunctionRegistryStorage.sol";
                                      import "../errors/LibSimpleFunctionRegistryRichErrors.sol";
                                      import "../migrations/LibBootstrap.sol";
                                      import "./IFeature.sol";
                                      import "./ISimpleFunctionRegistry.sol";
                                      /// @dev Basic registry management features.
                                      contract SimpleFunctionRegistry is
                                          IFeature,
                                          ISimpleFunctionRegistry,
                                          FixinCommon
                                      {
                                          // solhint-disable
                                          /// @dev Name of this feature.
                                          string public constant override FEATURE_NAME = "SimpleFunctionRegistry";
                                          /// @dev Version of this feature.
                                          uint256 public immutable override FEATURE_VERSION = _encodeVersion(1, 0, 0);
                                          /// @dev The deployed address of this contract.
                                          address private immutable _implementation;
                                          // solhint-enable
                                          using LibRichErrorsV06 for bytes;
                                          constructor() public {
                                              _implementation = address(this);
                                          }
                                          /// @dev Initializes this feature, registering its own functions.
                                          /// @return success Magic bytes if successful.
                                          function bootstrap()
                                              external
                                              returns (bytes4 success)
                                          {
                                              // Register the registration functions (inception vibes).
                                              _extend(this.extend.selector, _implementation);
                                              _extend(this._extendSelf.selector, _implementation);
                                              // Register the rollback function.
                                              _extend(this.rollback.selector, _implementation);
                                              // Register getters.
                                              _extend(this.getRollbackLength.selector, _implementation);
                                              _extend(this.getRollbackEntryAtIndex.selector, _implementation);
                                              return LibBootstrap.BOOTSTRAP_SUCCESS;
                                          }
                                          /// @dev Roll back to a prior implementation of a function.
                                          ///      Only directly callable by an authority.
                                          /// @param selector The function selector.
                                          /// @param targetImpl The address of an older implementation of the function.
                                          function rollback(bytes4 selector, address targetImpl)
                                              external
                                              override
                                              onlyOwner
                                          {
                                              (
                                                  LibSimpleFunctionRegistryStorage.Storage storage stor,
                                                  LibProxyStorage.Storage storage proxyStor
                                              ) = _getStorages();
                                              address currentImpl = proxyStor.impls[selector];
                                              if (currentImpl == targetImpl) {
                                                  // Do nothing if already at targetImpl.
                                                  return;
                                              }
                                              // Walk history backwards until we find the target implementation.
                                              address[] storage history = stor.implHistory[selector];
                                              uint256 i = history.length;
                                              for (; i > 0; --i) {
                                                  address impl = history[i - 1];
                                                  history.pop();
                                                  if (impl == targetImpl) {
                                                      break;
                                                  }
                                              }
                                              if (i == 0) {
                                                  LibSimpleFunctionRegistryRichErrors.NotInRollbackHistoryError(
                                                      selector,
                                                      targetImpl
                                                  ).rrevert();
                                              }
                                              proxyStor.impls[selector] = targetImpl;
                                              emit ProxyFunctionUpdated(selector, currentImpl, targetImpl);
                                          }
                                          /// @dev Register or replace a function.
                                          ///      Only directly callable by an authority.
                                          /// @param selector The function selector.
                                          /// @param impl The implementation contract for the function.
                                          function extend(bytes4 selector, address impl)
                                              external
                                              override
                                              onlyOwner
                                          {
                                              _extend(selector, impl);
                                          }
                                          /// @dev Register or replace a function.
                                          ///      Only callable from within.
                                          ///      This function is only used during the bootstrap process and
                                          ///      should be deregistered by the deployer after bootstrapping is
                                          ///      complete.
                                          /// @param selector The function selector.
                                          /// @param impl The implementation contract for the function.
                                          function _extendSelf(bytes4 selector, address impl)
                                              external
                                              onlySelf
                                          {
                                              _extend(selector, impl);
                                          }
                                          /// @dev Retrieve the length of the rollback history for a function.
                                          /// @param selector The function selector.
                                          /// @return rollbackLength The number of items in the rollback history for
                                          ///         the function.
                                          function getRollbackLength(bytes4 selector)
                                              external
                                              override
                                              view
                                              returns (uint256 rollbackLength)
                                          {
                                              return LibSimpleFunctionRegistryStorage.getStorage().implHistory[selector].length;
                                          }
                                          /// @dev Retrieve an entry in the rollback history for a function.
                                          /// @param selector The function selector.
                                          /// @param idx The index in the rollback history.
                                          /// @return impl An implementation address for the function at
                                          ///         index `idx`.
                                          function getRollbackEntryAtIndex(bytes4 selector, uint256 idx)
                                              external
                                              override
                                              view
                                              returns (address impl)
                                          {
                                              return LibSimpleFunctionRegistryStorage.getStorage().implHistory[selector][idx];
                                          }
                                          /// @dev Register or replace a function.
                                          /// @param selector The function selector.
                                          /// @param impl The implementation contract for the function.
                                          function _extend(bytes4 selector, address impl)
                                              private
                                          {
                                              (
                                                  LibSimpleFunctionRegistryStorage.Storage storage stor,
                                                  LibProxyStorage.Storage storage proxyStor
                                              ) = _getStorages();
                                              address oldImpl = proxyStor.impls[selector];
                                              address[] storage history = stor.implHistory[selector];
                                              history.push(oldImpl);
                                              proxyStor.impls[selector] = impl;
                                              emit ProxyFunctionUpdated(selector, oldImpl, impl);
                                          }
                                          /// @dev Get the storage buckets for this feature and the proxy.
                                          /// @return stor Storage bucket for this feature.
                                          /// @return proxyStor age bucket for the proxy.
                                          function _getStorages()
                                              private
                                              pure
                                              returns (
                                                  LibSimpleFunctionRegistryStorage.Storage storage stor,
                                                  LibProxyStorage.Storage storage proxyStor
                                              )
                                          {
                                              return (
                                                  LibSimpleFunctionRegistryStorage.getStorage(),
                                                  LibProxyStorage.getStorage()
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "./LibStorage.sol";
                                      /// @dev Storage helpers for the `SimpleFunctionRegistry` feature.
                                      library LibSimpleFunctionRegistryStorage {
                                          /// @dev Storage bucket for this feature.
                                          struct Storage {
                                              // Mapping of function selector -> implementation history.
                                              mapping(bytes4 => address[]) implHistory;
                                          }
                                          /// @dev Get the storage bucket for this contract.
                                          function getStorage() internal pure returns (Storage storage stor) {
                                              uint256 storageSlot = LibStorage.getStorageSlot(
                                                  LibStorage.StorageId.SimpleFunctionRegistry
                                              );
                                              // Dip into assembly to change the slot pointed to by the local
                                              // variable `stor`.
                                              // See https://solidity.readthedocs.io/en/v0.6.8/assembly.html?highlight=slot#access-to-external-variables-functions-and-libraries
                                              assembly { stor_slot := storageSlot }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
                                      import "../errors/LibSpenderRichErrors.sol";
                                      import "../fixins/FixinCommon.sol";
                                      import "../migrations/LibMigrate.sol";
                                      import "../external/IAllowanceTarget.sol";
                                      import "../storage/LibTokenSpenderStorage.sol";
                                      import "./ITokenSpender.sol";
                                      import "./IFeature.sol";
                                      import "./ISimpleFunctionRegistry.sol";
                                      /// @dev Feature that allows spending token allowances.
                                      contract TokenSpender is
                                          IFeature,
                                          ITokenSpender,
                                          FixinCommon
                                      {
                                          // solhint-disable
                                          /// @dev Name of this feature.
                                          string public constant override FEATURE_NAME = "TokenSpender";
                                          /// @dev Version of this feature.
                                          uint256 public immutable override FEATURE_VERSION = _encodeVersion(1, 0, 0);
                                          /// @dev The implementation address of this feature.
                                          address private immutable _implementation;
                                          // solhint-enable
                                          using LibRichErrorsV06 for bytes;
                                          constructor() public {
                                              _implementation = address(this);
                                          }
                                          /// @dev Initialize and register this feature. Should be delegatecalled
                                          ///      into during a `Migrate.migrate()`.
                                          /// @param allowanceTarget An `allowanceTarget` instance, configured to have
                                          ///        the ZeroeEx contract as an authority.
                                          /// @return success `MIGRATE_SUCCESS` on success.
                                          function migrate(IAllowanceTarget allowanceTarget) external returns (bytes4 success) {
                                              LibTokenSpenderStorage.getStorage().allowanceTarget = allowanceTarget;
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this.getAllowanceTarget.selector, _implementation);
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this._spendERC20Tokens.selector, _implementation);
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this.getSpendableERC20BalanceOf.selector, _implementation);
                                              return LibMigrate.MIGRATE_SUCCESS;
                                          }
                                          /// @dev Transfers ERC20 tokens from `owner` to `to`. Only callable from within.
                                          /// @param token The token to spend.
                                          /// @param owner The owner of the tokens.
                                          /// @param to The recipient of the tokens.
                                          /// @param amount The amount of `token` to transfer.
                                          function _spendERC20Tokens(
                                              IERC20TokenV06 token,
                                              address owner,
                                              address to,
                                              uint256 amount
                                          )
                                              external
                                              override
                                              onlySelf
                                          {
                                              IAllowanceTarget spender = LibTokenSpenderStorage.getStorage().allowanceTarget;
                                              // Have the allowance target execute an ERC20 `transferFrom()`.
                                              (bool didSucceed, bytes memory resultData) = address(spender).call(
                                                  abi.encodeWithSelector(
                                                      IAllowanceTarget.executeCall.selector,
                                                      address(token),
                                                      abi.encodeWithSelector(
                                                          IERC20TokenV06.transferFrom.selector,
                                                          owner,
                                                          to,
                                                          amount
                                                      )
                                                  )
                                              );
                                              if (didSucceed) {
                                                  resultData = abi.decode(resultData, (bytes));
                                              }
                                              if (!didSucceed || !LibERC20TokenV06.isSuccessfulResult(resultData)) {
                                                  LibSpenderRichErrors.SpenderERC20TransferFromFailedError(
                                                      address(token),
                                                      owner,
                                                      to,
                                                      amount,
                                                      resultData
                                                  ).rrevert();
                                              }
                                          }
                                          /// @dev Gets the maximum amount of an ERC20 token `token` that can be
                                          ///      pulled from `owner` by the token spender.
                                          /// @param token The token to spend.
                                          /// @param owner The owner of the tokens.
                                          /// @return amount The amount of tokens that can be pulled.
                                          function getSpendableERC20BalanceOf(IERC20TokenV06 token, address owner)
                                              external
                                              override
                                              view
                                              returns (uint256 amount)
                                          {
                                              return LibSafeMathV06.min256(
                                                  token.allowance(owner, address(LibTokenSpenderStorage.getStorage().allowanceTarget)),
                                                  token.balanceOf(owner)
                                              );
                                          }
                                          /// @dev Get the address of the allowance target.
                                          /// @return target The target of token allowances.
                                          function getAllowanceTarget()
                                              external
                                              override
                                              view
                                              returns (address target)
                                          {
                                              return address(LibTokenSpenderStorage.getStorage().allowanceTarget);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./errors/LibRichErrorsV06.sol";
                                      import "./errors/LibSafeMathRichErrorsV06.sol";
                                      library LibSafeMathV06 {
                                          function safeMul(uint256 a, uint256 b)
                                              internal
                                              pure
                                              returns (uint256)
                                          {
                                              if (a == 0) {
                                                  return 0;
                                              }
                                              uint256 c = a * b;
                                              if (c / a != b) {
                                                  LibRichErrorsV06.rrevert(LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                      LibSafeMathRichErrorsV06.BinOpErrorCodes.MULTIPLICATION_OVERFLOW,
                                                      a,
                                                      b
                                                  ));
                                              }
                                              return c;
                                          }
                                          function safeDiv(uint256 a, uint256 b)
                                              internal
                                              pure
                                              returns (uint256)
                                          {
                                              if (b == 0) {
                                                  LibRichErrorsV06.rrevert(LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                      LibSafeMathRichErrorsV06.BinOpErrorCodes.DIVISION_BY_ZERO,
                                                      a,
                                                      b
                                                  ));
                                              }
                                              uint256 c = a / b;
                                              return c;
                                          }
                                          function safeSub(uint256 a, uint256 b)
                                              internal
                                              pure
                                              returns (uint256)
                                          {
                                              if (b > a) {
                                                  LibRichErrorsV06.rrevert(LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                      LibSafeMathRichErrorsV06.BinOpErrorCodes.SUBTRACTION_UNDERFLOW,
                                                      a,
                                                      b
                                                  ));
                                              }
                                              return a - b;
                                          }
                                          function safeAdd(uint256 a, uint256 b)
                                              internal
                                              pure
                                              returns (uint256)
                                          {
                                              uint256 c = a + b;
                                              if (c < a) {
                                                  LibRichErrorsV06.rrevert(LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                      LibSafeMathRichErrorsV06.BinOpErrorCodes.ADDITION_OVERFLOW,
                                                      a,
                                                      b
                                                  ));
                                              }
                                              return c;
                                          }
                                          function max256(uint256 a, uint256 b)
                                              internal
                                              pure
                                              returns (uint256)
                                          {
                                              return a >= b ? a : b;
                                          }
                                          function min256(uint256 a, uint256 b)
                                              internal
                                              pure
                                              returns (uint256)
                                          {
                                              return a < b ? a : b;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibSafeMathRichErrorsV06 {
                                          // bytes4(keccak256("Uint256BinOpError(uint8,uint256,uint256)"))
                                          bytes4 internal constant UINT256_BINOP_ERROR_SELECTOR =
                                              0xe946c1bb;
                                          // bytes4(keccak256("Uint256DowncastError(uint8,uint256)"))
                                          bytes4 internal constant UINT256_DOWNCAST_ERROR_SELECTOR =
                                              0xc996af7b;
                                          enum BinOpErrorCodes {
                                              ADDITION_OVERFLOW,
                                              MULTIPLICATION_OVERFLOW,
                                              SUBTRACTION_UNDERFLOW,
                                              DIVISION_BY_ZERO
                                          }
                                          enum DowncastErrorCodes {
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT32,
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT64,
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT96
                                          }
                                          // solhint-disable func-name-mixedcase
                                          function Uint256BinOpError(
                                              BinOpErrorCodes errorCode,
                                              uint256 a,
                                              uint256 b
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  UINT256_BINOP_ERROR_SELECTOR,
                                                  errorCode,
                                                  a,
                                                  b
                                              );
                                          }
                                          function Uint256DowncastError(
                                              DowncastErrorCodes errorCode,
                                              uint256 a
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  UINT256_DOWNCAST_ERROR_SELECTOR,
                                                  errorCode,
                                                  a
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
                                      import "./IERC20TokenV06.sol";
                                      library LibERC20TokenV06 {
                                          bytes constant private DECIMALS_CALL_DATA = hex"313ce567";
                                          /// @dev Calls `IERC20TokenV06(token).approve()`.
                                          ///      Reverts if the result fails `isSuccessfulResult()` or the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param spender The address that receives an allowance.
                                          /// @param allowance The allowance to set.
                                          function compatApprove(
                                              IERC20TokenV06 token,
                                              address spender,
                                              uint256 allowance
                                          )
                                              internal
                                          {
                                              bytes memory callData = abi.encodeWithSelector(
                                                  token.approve.selector,
                                                  spender,
                                                  allowance
                                              );
                                              _callWithOptionalBooleanResult(address(token), callData);
                                          }
                                          /// @dev Calls `IERC20TokenV06(token).approve()` and sets the allowance to the
                                          ///      maximum if the current approval is not already >= an amount.
                                          ///      Reverts if the result fails `isSuccessfulResult()` or the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param spender The address that receives an allowance.
                                          /// @param amount The minimum allowance needed.
                                          function approveIfBelow(
                                              IERC20TokenV06 token,
                                              address spender,
                                              uint256 amount
                                          )
                                              internal
                                          {
                                              if (token.allowance(address(this), spender) < amount) {
                                                  compatApprove(token, spender, uint256(-1));
                                              }
                                          }
                                          /// @dev Calls `IERC20TokenV06(token).transfer()`.
                                          ///      Reverts if the result fails `isSuccessfulResult()` or the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param to The address that receives the tokens
                                          /// @param amount Number of tokens to transfer.
                                          function compatTransfer(
                                              IERC20TokenV06 token,
                                              address to,
                                              uint256 amount
                                          )
                                              internal
                                          {
                                              bytes memory callData = abi.encodeWithSelector(
                                                  token.transfer.selector,
                                                  to,
                                                  amount
                                              );
                                              _callWithOptionalBooleanResult(address(token), callData);
                                          }
                                          /// @dev Calls `IERC20TokenV06(token).transferFrom()`.
                                          ///      Reverts if the result fails `isSuccessfulResult()` or the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param from The owner of the tokens.
                                          /// @param to The address that receives the tokens
                                          /// @param amount Number of tokens to transfer.
                                          function compatTransferFrom(
                                              IERC20TokenV06 token,
                                              address from,
                                              address to,
                                              uint256 amount
                                          )
                                              internal
                                          {
                                              bytes memory callData = abi.encodeWithSelector(
                                                  token.transferFrom.selector,
                                                  from,
                                                  to,
                                                  amount
                                              );
                                              _callWithOptionalBooleanResult(address(token), callData);
                                          }
                                          /// @dev Retrieves the number of decimals for a token.
                                          ///      Returns `18` if the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @return tokenDecimals The number of decimals places for the token.
                                          function compatDecimals(IERC20TokenV06 token)
                                              internal
                                              view
                                              returns (uint8 tokenDecimals)
                                          {
                                              tokenDecimals = 18;
                                              (bool didSucceed, bytes memory resultData) = address(token).staticcall(DECIMALS_CALL_DATA);
                                              if (didSucceed && resultData.length == 32) {
                                                  tokenDecimals = uint8(LibBytesV06.readUint256(resultData, 0));
                                              }
                                          }
                                          /// @dev Retrieves the allowance for a token, owner, and spender.
                                          ///      Returns `0` if the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param owner The owner of the tokens.
                                          /// @param spender The address the spender.
                                          /// @return allowance_ The allowance for a token, owner, and spender.
                                          function compatAllowance(IERC20TokenV06 token, address owner, address spender)
                                              internal
                                              view
                                              returns (uint256 allowance_)
                                          {
                                              (bool didSucceed, bytes memory resultData) = address(token).staticcall(
                                                  abi.encodeWithSelector(
                                                      token.allowance.selector,
                                                      owner,
                                                      spender
                                                  )
                                              );
                                              if (didSucceed && resultData.length == 32) {
                                                  allowance_ = LibBytesV06.readUint256(resultData, 0);
                                              }
                                          }
                                          /// @dev Retrieves the balance for a token owner.
                                          ///      Returns `0` if the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param owner The owner of the tokens.
                                          /// @return balance The token balance of an owner.
                                          function compatBalanceOf(IERC20TokenV06 token, address owner)
                                              internal
                                              view
                                              returns (uint256 balance)
                                          {
                                              (bool didSucceed, bytes memory resultData) = address(token).staticcall(
                                                  abi.encodeWithSelector(
                                                      token.balanceOf.selector,
                                                      owner
                                                  )
                                              );
                                              if (didSucceed && resultData.length == 32) {
                                                  balance = LibBytesV06.readUint256(resultData, 0);
                                              }
                                          }
                                          /// @dev Check if the data returned by a non-static call to an ERC20 token
                                          ///      is a successful result. Supported functions are `transfer()`,
                                          ///      `transferFrom()`, and `approve()`.
                                          /// @param resultData The raw data returned by a non-static call to the ERC20 token.
                                          /// @return isSuccessful Whether the result data indicates success.
                                          function isSuccessfulResult(bytes memory resultData)
                                              internal
                                              pure
                                              returns (bool isSuccessful)
                                          {
                                              if (resultData.length == 0) {
                                                  return true;
                                              }
                                              if (resultData.length == 32) {
                                                  uint256 result = LibBytesV06.readUint256(resultData, 0);
                                                  if (result == 1) {
                                                      return true;
                                                  }
                                              }
                                          }
                                          /// @dev Executes a call on address `target` with calldata `callData`
                                          ///      and asserts that either nothing was returned or a single boolean
                                          ///      was returned equal to `true`.
                                          /// @param target The call target.
                                          /// @param callData The abi-encoded call data.
                                          function _callWithOptionalBooleanResult(
                                              address target,
                                              bytes memory callData
                                          )
                                              private
                                          {
                                              (bool didSucceed, bytes memory resultData) = target.call(callData);
                                              if (didSucceed && isSuccessfulResult(resultData)) {
                                                  return;
                                              }
                                              LibRichErrorsV06.rrevert(resultData);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "./LibStorage.sol";
                                      import "../external/IAllowanceTarget.sol";
                                      /// @dev Storage helpers for the `TokenSpender` feature.
                                      library LibTokenSpenderStorage {
                                          /// @dev Storage bucket for this feature.
                                          struct Storage {
                                              // Allowance target contract.
                                              IAllowanceTarget allowanceTarget;
                                          }
                                          /// @dev Get the storage bucket for this contract.
                                          function getStorage() internal pure returns (Storage storage stor) {
                                              uint256 storageSlot = LibStorage.getStorageSlot(
                                                  LibStorage.StorageId.TokenSpender
                                              );
                                              // Dip into assembly to change the slot pointed to by the local
                                              // variable `stor`.
                                              // See https://solidity.readthedocs.io/en/v0.6.8/assembly.html?highlight=slot#access-to-external-variables-functions-and-libraries
                                              assembly { stor_slot := storageSlot }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../errors/LibTransformERC20RichErrors.sol";
                                      import "../fixins/FixinCommon.sol";
                                      import "../migrations/LibMigrate.sol";
                                      import "../external/IFlashWallet.sol";
                                      import "../external/FlashWallet.sol";
                                      import "../storage/LibTransformERC20Storage.sol";
                                      import "../transformers/IERC20Transformer.sol";
                                      import "../transformers/LibERC20Transformer.sol";
                                      import "./ITransformERC20.sol";
                                      import "./ITokenSpender.sol";
                                      import "./IFeature.sol";
                                      import "./ISimpleFunctionRegistry.sol";
                                      /// @dev Feature to composably transform between ERC20 tokens.
                                      contract TransformERC20 is
                                          IFeature,
                                          ITransformERC20,
                                          FixinCommon
                                      {
                                          /// @dev Stack vars for `_transformERC20Private()`.
                                          struct TransformERC20PrivateState {
                                              IFlashWallet wallet;
                                              address transformerDeployer;
                                              uint256 takerOutputTokenBalanceBefore;
                                              uint256 takerOutputTokenBalanceAfter;
                                          }
                                          // solhint-disable
                                          /// @dev Name of this feature.
                                          string public constant override FEATURE_NAME = "TransformERC20";
                                          /// @dev Version of this feature.
                                          uint256 public immutable override FEATURE_VERSION = _encodeVersion(1, 0, 0);
                                          /// @dev The implementation address of this feature.
                                          address private immutable _implementation;
                                          // solhint-enable
                                          using LibSafeMathV06 for uint256;
                                          using LibRichErrorsV06 for bytes;
                                          constructor() public {
                                              _implementation = address(this);
                                          }
                                          /// @dev Initialize and register this feature.
                                          ///      Should be delegatecalled by `Migrate.migrate()`.
                                          /// @param transformerDeployer The trusted deployer for transformers.
                                          /// @return success `LibMigrate.SUCCESS` on success.
                                          function migrate(address transformerDeployer) external returns (bytes4 success) {
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this.getTransformerDeployer.selector, _implementation);
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this.createTransformWallet.selector, _implementation);
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this.getTransformWallet.selector, _implementation);
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this.setTransformerDeployer.selector, _implementation);
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this.transformERC20.selector, _implementation);
                                              ISimpleFunctionRegistry(address(this))
                                                  .extend(this._transformERC20.selector, _implementation);
                                              createTransformWallet();
                                              LibTransformERC20Storage.getStorage().transformerDeployer = transformerDeployer;
                                              return LibMigrate.MIGRATE_SUCCESS;
                                          }
                                          /// @dev Replace the allowed deployer for transformers.
                                          ///      Only callable by the owner.
                                          /// @param transformerDeployer The address of the trusted deployer for transformers.
                                          function setTransformerDeployer(address transformerDeployer)
                                              external
                                              override
                                              onlyOwner
                                          {
                                              LibTransformERC20Storage.getStorage().transformerDeployer = transformerDeployer;
                                              emit TransformerDeployerUpdated(transformerDeployer);
                                          }
                                          /// @dev Return the allowed deployer for transformers.
                                          /// @return deployer The transform deployer address.
                                          function getTransformerDeployer()
                                              public
                                              override
                                              view
                                              returns (address deployer)
                                          {
                                              return LibTransformERC20Storage.getStorage().transformerDeployer;
                                          }
                                          /// @dev Deploy a new wallet instance and replace the current one with it.
                                          ///      Useful if we somehow break the current wallet instance.
                                          ///      Anyone can call this.
                                          /// @return wallet The new wallet instance.
                                          function createTransformWallet()
                                              public
                                              override
                                              returns (IFlashWallet wallet)
                                          {
                                              wallet = new FlashWallet();
                                              LibTransformERC20Storage.getStorage().wallet = wallet;
                                          }
                                          /// @dev Executes a series of transformations to convert an ERC20 `inputToken`
                                          ///      to an ERC20 `outputToken`.
                                          /// @param inputToken The token being provided by the sender.
                                          ///        If `0xeee...`, ETH is implied and should be provided with the call.`
                                          /// @param outputToken The token to be acquired by the sender.
                                          ///        `0xeee...` implies ETH.
                                          /// @param inputTokenAmount The amount of `inputToken` to take from the sender.
                                          ///        If set to `uint256(-1)`, the entire spendable balance of the taker
                                          ///        will be solt.
                                          /// @param minOutputTokenAmount The minimum amount of `outputToken` the sender
                                          ///        must receive for the entire transformation to succeed. If set to zero,
                                          ///        the minimum output token transfer will not be asserted.
                                          /// @param transformations The transformations to execute on the token balance(s)
                                          ///        in sequence.
                                          /// @return outputTokenAmount The amount of `outputToken` received by the sender.
                                          function transformERC20(
                                              IERC20TokenV06 inputToken,
                                              IERC20TokenV06 outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 minOutputTokenAmount,
                                              Transformation[] memory transformations
                                          )
                                              public
                                              override
                                              payable
                                              returns (uint256 outputTokenAmount)
                                          {
                                              return _transformERC20Private(
                                                  keccak256(msg.data),
                                                  msg.sender,
                                                  inputToken,
                                                  outputToken,
                                                  inputTokenAmount,
                                                  minOutputTokenAmount,
                                                  transformations
                                              );
                                          }
                                          /// @dev Internal version of `transformERC20()`. Only callable from within.
                                          /// @param callDataHash Hash of the ingress calldata.
                                          /// @param taker The taker address.
                                          /// @param inputToken The token being provided by the taker.
                                          ///        If `0xeee...`, ETH is implied and should be provided with the call.`
                                          /// @param outputToken The token to be acquired by the taker.
                                          ///        `0xeee...` implies ETH.
                                          /// @param inputTokenAmount The amount of `inputToken` to take from the taker.
                                          ///        If set to `uint256(-1)`, the entire spendable balance of the taker
                                          ///        will be solt.
                                          /// @param minOutputTokenAmount The minimum amount of `outputToken` the taker
                                          ///        must receive for the entire transformation to succeed. If set to zero,
                                          ///        the minimum output token transfer will not be asserted.
                                          /// @param transformations The transformations to execute on the token balance(s)
                                          ///        in sequence.
                                          /// @return outputTokenAmount The amount of `outputToken` received by the taker.
                                          function _transformERC20(
                                              bytes32 callDataHash,
                                              address payable taker,
                                              IERC20TokenV06 inputToken,
                                              IERC20TokenV06 outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 minOutputTokenAmount,
                                              Transformation[] memory transformations
                                          )
                                              public
                                              override
                                              payable
                                              onlySelf
                                              returns (uint256 outputTokenAmount)
                                          {
                                              return _transformERC20Private(
                                                  callDataHash,
                                                  taker,
                                                  inputToken,
                                                  outputToken,
                                                  inputTokenAmount,
                                                  minOutputTokenAmount,
                                                  transformations
                                              );
                                          }
                                          /// @dev Private version of `transformERC20()`.
                                          /// @param callDataHash Hash of the ingress calldata.
                                          /// @param taker The taker address.
                                          /// @param inputToken The token being provided by the taker.
                                          ///        If `0xeee...`, ETH is implied and should be provided with the call.`
                                          /// @param outputToken The token to be acquired by the taker.
                                          ///        `0xeee...` implies ETH.
                                          /// @param inputTokenAmount The amount of `inputToken` to take from the taker.
                                          ///        If set to `uint256(-1)`, the entire spendable balance of the taker
                                          ///        will be solt.
                                          /// @param minOutputTokenAmount The minimum amount of `outputToken` the taker
                                          ///        must receive for the entire transformation to succeed. If set to zero,
                                          ///        the minimum output token transfer will not be asserted.
                                          /// @param transformations The transformations to execute on the token balance(s)
                                          ///        in sequence.
                                          /// @return outputTokenAmount The amount of `outputToken` received by the taker.
                                          function _transformERC20Private(
                                              bytes32 callDataHash,
                                              address payable taker,
                                              IERC20TokenV06 inputToken,
                                              IERC20TokenV06 outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 minOutputTokenAmount,
                                              Transformation[] memory transformations
                                          )
                                              private
                                              returns (uint256 outputTokenAmount)
                                          {
                                              // If the input token amount is -1, transform the taker's entire
                                              // spendable balance.
                                              if (inputTokenAmount == uint256(-1)) {
                                                  inputTokenAmount = ITokenSpender(address(this))
                                                      .getSpendableERC20BalanceOf(inputToken, taker);
                                              }
                                              TransformERC20PrivateState memory state;
                                              state.wallet = getTransformWallet();
                                              state.transformerDeployer = getTransformerDeployer();
                                              // Remember the initial output token balance of the taker.
                                              state.takerOutputTokenBalanceBefore =
                                                  LibERC20Transformer.getTokenBalanceOf(outputToken, taker);
                                              // Pull input tokens from the taker to the wallet and transfer attached ETH.
                                              _transferInputTokensAndAttachedEth(
                                                  inputToken,
                                                  taker,
                                                  address(state.wallet),
                                                  inputTokenAmount
                                              );
                                              // Perform transformations.
                                              for (uint256 i = 0; i < transformations.length; ++i) {
                                                  _executeTransformation(
                                                      state.wallet,
                                                      transformations[i],
                                                      state.transformerDeployer,
                                                      taker,
                                                      callDataHash
                                                  );
                                              }
                                              // Compute how much output token has been transferred to the taker.
                                              state.takerOutputTokenBalanceAfter =
                                                  LibERC20Transformer.getTokenBalanceOf(outputToken, taker);
                                              if (state.takerOutputTokenBalanceAfter > state.takerOutputTokenBalanceBefore) {
                                                  outputTokenAmount = state.takerOutputTokenBalanceAfter.safeSub(
                                                      state.takerOutputTokenBalanceBefore
                                                  );
                                              } else if (state.takerOutputTokenBalanceAfter < state.takerOutputTokenBalanceBefore) {
                                                  LibTransformERC20RichErrors.NegativeTransformERC20OutputError(
                                                      address(outputToken),
                                                      state.takerOutputTokenBalanceBefore - state.takerOutputTokenBalanceAfter
                                                  ).rrevert();
                                              }
                                              // Ensure enough output token has been sent to the taker.
                                              if (outputTokenAmount < minOutputTokenAmount) {
                                                  LibTransformERC20RichErrors.IncompleteTransformERC20Error(
                                                      address(outputToken),
                                                      outputTokenAmount,
                                                      minOutputTokenAmount
                                                  ).rrevert();
                                              }
                                              // Emit an event.
                                              emit TransformedERC20(
                                                  taker,
                                                  address(inputToken),
                                                  address(outputToken),
                                                  inputTokenAmount,
                                                  outputTokenAmount
                                              );
                                          }
                                          /// @dev Return the current wallet instance that will serve as the execution
                                          ///      context for transformations.
                                          /// @return wallet The wallet instance.
                                          function getTransformWallet()
                                              public
                                              override
                                              view
                                              returns (IFlashWallet wallet)
                                          {
                                              return LibTransformERC20Storage.getStorage().wallet;
                                          }
                                          /// @dev Transfer input tokens from the taker and any attached ETH to `to`
                                          /// @param inputToken The token to pull from the taker.
                                          /// @param from The from (taker) address.
                                          /// @param to The recipient of tokens and ETH.
                                          /// @param amount Amount of `inputToken` tokens to transfer.
                                          function _transferInputTokensAndAttachedEth(
                                              IERC20TokenV06 inputToken,
                                              address from,
                                              address payable to,
                                              uint256 amount
                                          )
                                              private
                                          {
                                              // Transfer any attached ETH.
                                              if (msg.value != 0) {
                                                  to.transfer(msg.value);
                                              }
                                              // Transfer input tokens.
                                              if (!LibERC20Transformer.isTokenETH(inputToken)) {
                                                  // Token is not ETH, so pull ERC20 tokens.
                                                  ITokenSpender(address(this))._spendERC20Tokens(
                                                      inputToken,
                                                      from,
                                                      to,
                                                      amount
                                                  );
                                              } else if (msg.value < amount) {
                                                   // Token is ETH, so the caller must attach enough ETH to the call.
                                                  LibTransformERC20RichErrors.InsufficientEthAttachedError(
                                                      msg.value,
                                                      amount
                                                  ).rrevert();
                                              }
                                          }
                                          /// @dev Executs a transformer in the context of `wallet`.
                                          /// @param wallet The wallet instance.
                                          /// @param transformation The transformation.
                                          /// @param transformerDeployer The address of the transformer deployer.
                                          /// @param taker The taker address.
                                          /// @param callDataHash Hash of the calldata.
                                          function _executeTransformation(
                                              IFlashWallet wallet,
                                              Transformation memory transformation,
                                              address transformerDeployer,
                                              address payable taker,
                                              bytes32 callDataHash
                                          )
                                              private
                                          {
                                              // Derive the transformer address from the deployment nonce.
                                              address payable transformer = LibERC20Transformer.getDeployedAddress(
                                                  transformerDeployer,
                                                  transformation.deploymentNonce
                                              );
                                              // Call `transformer.transform()` as the wallet.
                                              bytes memory resultData = wallet.executeDelegateCall(
                                                  // The call target.
                                                  transformer,
                                                  // Call data.
                                                  abi.encodeWithSelector(
                                                      IERC20Transformer.transform.selector,
                                                      callDataHash,
                                                      taker,
                                                      transformation.data
                                                  )
                                              );
                                              // Ensure the transformer returned the magic bytes.
                                              if (resultData.length != 32 ||
                                                  abi.decode(resultData, (bytes4)) != LibERC20Transformer.TRANSFORMER_SUCCESS
                                              ) {
                                                  LibTransformERC20RichErrors.TransformerFailedError(
                                                      transformer,
                                                      transformation.data,
                                                      resultData
                                                  ).rrevert();
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "./LibStorage.sol";
                                      import "../external/IFlashWallet.sol";
                                      /// @dev Storage helpers for the `TokenSpender` feature.
                                      library LibTransformERC20Storage {
                                          /// @dev Storage bucket for this feature.
                                          struct Storage {
                                              // The current wallet instance.
                                              IFlashWallet wallet;
                                              // The transformer deployer address.
                                              address transformerDeployer;
                                          }
                                          /// @dev Get the storage bucket for this contract.
                                          function getStorage() internal pure returns (Storage storage stor) {
                                              uint256 storageSlot = LibStorage.getStorageSlot(
                                                  LibStorage.StorageId.TransformERC20
                                              );
                                              // Dip into assembly to change the slot pointed to by the local
                                              // variable `stor`.
                                              // See https://solidity.readthedocs.io/en/v0.6.8/assembly.html?highlight=slot#access-to-external-variables-functions-and-libraries
                                              assembly { stor_slot := storageSlot }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
                                      library LibERC20Transformer {
                                          using LibERC20TokenV06 for IERC20TokenV06;
                                          /// @dev ETH pseudo-token address.
                                          address constant internal ETH_TOKEN_ADDRESS = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
                                          /// @dev Return value indicating success in `IERC20Transformer.transform()`.
                                          ///      This is just `keccak256('TRANSFORMER_SUCCESS')`.
                                          bytes4 constant internal TRANSFORMER_SUCCESS = 0x13c9929e;
                                          /// @dev Transfer ERC20 tokens and ETH.
                                          /// @param token An ERC20 or the ETH pseudo-token address (`ETH_TOKEN_ADDRESS`).
                                          /// @param to The recipient.
                                          /// @param amount The transfer amount.
                                          function transformerTransfer(
                                              IERC20TokenV06 token,
                                              address payable to,
                                              uint256 amount
                                          )
                                              internal
                                          {
                                              if (isTokenETH(token)) {
                                                  to.transfer(amount);
                                              } else {
                                                  token.compatTransfer(to, amount);
                                              }
                                          }
                                          /// @dev Check if a token is the ETH pseudo-token.
                                          /// @param token The token to check.
                                          /// @return isETH `true` if the token is the ETH pseudo-token.
                                          function isTokenETH(IERC20TokenV06 token)
                                              internal
                                              pure
                                              returns (bool isETH)
                                          {
                                              return address(token) == ETH_TOKEN_ADDRESS;
                                          }
                                          /// @dev Check the balance of an ERC20 token or ETH.
                                          /// @param token An ERC20 or the ETH pseudo-token address (`ETH_TOKEN_ADDRESS`).
                                          /// @param owner Holder of the tokens.
                                          /// @return tokenBalance The balance of `owner`.
                                          function getTokenBalanceOf(IERC20TokenV06 token, address owner)
                                              internal
                                              view
                                              returns (uint256 tokenBalance)
                                          {
                                              if (isTokenETH(token)) {
                                                  return owner.balance;
                                              }
                                              return token.balanceOf(owner);
                                          }
                                          /// @dev RLP-encode a 32-bit or less account nonce.
                                          /// @param nonce A positive integer in the range 0 <= nonce < 2^32.
                                          /// @return rlpNonce The RLP encoding.
                                          function rlpEncodeNonce(uint32 nonce)
                                              internal
                                              pure
                                              returns (bytes memory rlpNonce)
                                          {
                                              // See https://github.com/ethereum/wiki/wiki/RLP for RLP encoding rules.
                                              if (nonce == 0) {
                                                  rlpNonce = new bytes(1);
                                                  rlpNonce[0] = 0x80;
                                              } else if (nonce < 0x80) {
                                                  rlpNonce = new bytes(1);
                                                  rlpNonce[0] = byte(uint8(nonce));
                                              } else if (nonce <= 0xFF) {
                                                  rlpNonce = new bytes(2);
                                                  rlpNonce[0] = 0x81;
                                                  rlpNonce[1] = byte(uint8(nonce));
                                              } else if (nonce <= 0xFFFF) {
                                                  rlpNonce = new bytes(3);
                                                  rlpNonce[0] = 0x82;
                                                  rlpNonce[1] = byte(uint8((nonce & 0xFF00) >> 8));
                                                  rlpNonce[2] = byte(uint8(nonce));
                                              } else if (nonce <= 0xFFFFFF) {
                                                  rlpNonce = new bytes(4);
                                                  rlpNonce[0] = 0x83;
                                                  rlpNonce[1] = byte(uint8((nonce & 0xFF0000) >> 16));
                                                  rlpNonce[2] = byte(uint8((nonce & 0xFF00) >> 8));
                                                  rlpNonce[3] = byte(uint8(nonce));
                                              } else {
                                                  rlpNonce = new bytes(5);
                                                  rlpNonce[0] = 0x84;
                                                  rlpNonce[1] = byte(uint8((nonce & 0xFF000000) >> 24));
                                                  rlpNonce[2] = byte(uint8((nonce & 0xFF0000) >> 16));
                                                  rlpNonce[3] = byte(uint8((nonce & 0xFF00) >> 8));
                                                  rlpNonce[4] = byte(uint8(nonce));
                                              }
                                          }
                                          /// @dev Compute the expected deployment address by `deployer` at
                                          ///      the nonce given by `deploymentNonce`.
                                          /// @param deployer The address of the deployer.
                                          /// @param deploymentNonce The nonce that the deployer had when deploying
                                          ///        a contract.
                                          /// @return deploymentAddress The deployment address.
                                          function getDeployedAddress(address deployer, uint32 deploymentNonce)
                                              internal
                                              pure
                                              returns (address payable deploymentAddress)
                                          {
                                              // The address of if a deployed contract is the lower 20 bytes of the
                                              // hash of the RLP-encoded deployer's account address + account nonce.
                                              // See: https://ethereum.stackexchange.com/questions/760/how-is-the-address-of-an-ethereum-contract-computed
                                              bytes memory rlpNonce = rlpEncodeNonce(deploymentNonce);
                                              return address(uint160(uint256(keccak256(abi.encodePacked(
                                                  byte(uint8(0xC0 + 21 + rlpNonce.length)),
                                                  byte(uint8(0x80 + 20)),
                                                  deployer,
                                                  rlpNonce
                                              )))));
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../ZeroEx.sol";
                                      import "../features/IOwnable.sol";
                                      import "../features/TokenSpender.sol";
                                      import "../features/TransformERC20.sol";
                                      import "../external/AllowanceTarget.sol";
                                      import "./InitialMigration.sol";
                                      /// @dev A contract for deploying and configuring the full ZeroEx contract.
                                      contract FullMigration {
                                          // solhint-disable no-empty-blocks,indent
                                          /// @dev Features to add the the proxy contract.
                                          struct Features {
                                              SimpleFunctionRegistry registry;
                                              Ownable ownable;
                                              TokenSpender tokenSpender;
                                              TransformERC20 transformERC20;
                                          }
                                          /// @dev Parameters needed to initialize features.
                                          struct MigrateOpts {
                                              address transformerDeployer;
                                          }
                                          /// @dev The allowed caller of `deploy()`.
                                          address public immutable deployer;
                                          /// @dev The initial migration contract.
                                          InitialMigration private _initialMigration;
                                          /// @dev Instantiate this contract and set the allowed caller of `deploy()`
                                          ///      to `deployer`.
                                          /// @param deployer_ The allowed caller of `deploy()`.
                                          constructor(address payable deployer_)
                                              public
                                          {
                                              deployer = deployer_;
                                              // Create an initial migration contract with this contract set to the
                                              // allowed deployer.
                                              _initialMigration = new InitialMigration(address(this));
                                          }
                                          /// @dev Deploy the `ZeroEx` contract with the full feature set,
                                          ///      transfer ownership to `owner`, then self-destruct.
                                          /// @param owner The owner of the contract.
                                          /// @param features Features to add to the proxy.
                                          /// @return zeroEx The deployed and configured `ZeroEx` contract.
                                          /// @param migrateOpts Parameters needed to initialize features.
                                          function deploy(
                                              address payable owner,
                                              Features memory features,
                                              MigrateOpts memory migrateOpts
                                          )
                                              public
                                              returns (ZeroEx zeroEx)
                                          {
                                              require(msg.sender == deployer, "FullMigration/INVALID_SENDER");
                                              // Perform the initial migration with the owner set to this contract.
                                              zeroEx = _initialMigration.deploy(
                                                  address(uint160(address(this))),
                                                  InitialMigration.BootstrapFeatures({
                                                      registry: features.registry,
                                                      ownable: features.ownable
                                                  })
                                              );
                                              // Add features.
                                              _addFeatures(zeroEx, owner, features, migrateOpts);
                                              // Transfer ownership to the real owner.
                                              IOwnable(address(zeroEx)).transferOwnership(owner);
                                              // Self-destruct.
                                              this.die(owner);
                                          }
                                          /// @dev Destroy this contract. Only callable from ourselves (from `deploy()`).
                                          /// @param ethRecipient Receiver of any ETH in this contract.
                                          function die(address payable ethRecipient)
                                              external
                                              virtual
                                          {
                                              require(msg.sender == address(this), "FullMigration/INVALID_SENDER");
                                              // This contract should not hold any funds but we send
                                              // them to the ethRecipient just in case.
                                              selfdestruct(ethRecipient);
                                          }
                                          /// @dev Deploy and register features to the ZeroEx contract.
                                          /// @param zeroEx The bootstrapped ZeroEx contract.
                                          /// @param owner The ultimate owner of the ZeroEx contract.
                                          /// @param features Features to add to the proxy.
                                          /// @param migrateOpts Parameters needed to initialize features.
                                          function _addFeatures(
                                              ZeroEx zeroEx,
                                              address owner,
                                              Features memory features,
                                              MigrateOpts memory migrateOpts
                                          )
                                              private
                                          {
                                              IOwnable ownable = IOwnable(address(zeroEx));
                                              // TokenSpender
                                              {
                                                  // Create the allowance target.
                                                  AllowanceTarget allowanceTarget = new AllowanceTarget();
                                                  // Let the ZeroEx contract use the allowance target.
                                                  allowanceTarget.addAuthorizedAddress(address(zeroEx));
                                                  // Transfer ownership of the allowance target to the (real) owner.
                                                  allowanceTarget.transferOwnership(owner);
                                                  // Register the feature.
                                                  ownable.migrate(
                                                      address(features.tokenSpender),
                                                      abi.encodeWithSelector(
                                                          TokenSpender.migrate.selector,
                                                          allowanceTarget
                                                      ),
                                                      address(this)
                                                  );
                                              }
                                              // TransformERC20
                                              {
                                                  // Register the feature.
                                                  ownable.migrate(
                                                      address(features.transformERC20),
                                                      abi.encodeWithSelector(
                                                          TransformERC20.migrate.selector,
                                                          migrateOpts.transformerDeployer
                                                      ),
                                                      address(this)
                                                  );
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../ZeroEx.sol";
                                      import "../features/IBootstrap.sol";
                                      import "../features/SimpleFunctionRegistry.sol";
                                      import "../features/Ownable.sol";
                                      import "./LibBootstrap.sol";
                                      /// @dev A contract for deploying and configuring a minimal ZeroEx contract.
                                      contract InitialMigration {
                                          /// @dev Features to bootstrap into the the proxy contract.
                                          struct BootstrapFeatures {
                                              SimpleFunctionRegistry registry;
                                              Ownable ownable;
                                          }
                                          /// @dev The allowed caller of `deploy()`. In production, this would be
                                          ///      the governor.
                                          address public immutable deployer;
                                          /// @dev The real address of this contract.
                                          address private immutable _implementation;
                                          /// @dev Instantiate this contract and set the allowed caller of `deploy()`
                                          ///      to `deployer_`.
                                          /// @param deployer_ The allowed caller of `deploy()`.
                                          constructor(address deployer_) public {
                                              deployer = deployer_;
                                              _implementation = address(this);
                                          }
                                          /// @dev Deploy the `ZeroEx` contract with the minimum feature set,
                                          ///      transfers ownership to `owner`, then self-destructs.
                                          ///      Only callable by `deployer` set in the contstructor.
                                          /// @param owner The owner of the contract.
                                          /// @param features Features to bootstrap into the proxy.
                                          /// @return zeroEx The deployed and configured `ZeroEx` contract.
                                          function deploy(address payable owner, BootstrapFeatures memory features)
                                              public
                                              virtual
                                              returns (ZeroEx zeroEx)
                                          {
                                              // Must be called by the allowed deployer.
                                              require(msg.sender == deployer, "InitialMigration/INVALID_SENDER");
                                              // Deploy the ZeroEx contract, setting ourselves as the bootstrapper.
                                              zeroEx = new ZeroEx();
                                              // Bootstrap the initial feature set.
                                              IBootstrap(address(zeroEx)).bootstrap(
                                                  address(this),
                                                  abi.encodeWithSelector(this.bootstrap.selector, owner, features)
                                              );
                                              // Self-destruct. This contract should not hold any funds but we send
                                              // them to the owner just in case.
                                              this.die(owner);
                                          }
                                          /// @dev Sets up the initial state of the `ZeroEx` contract.
                                          ///      The `ZeroEx` contract will delegatecall into this function.
                                          /// @param owner The new owner of the ZeroEx contract.
                                          /// @param features Features to bootstrap into the proxy.
                                          /// @return success Magic bytes if successful.
                                          function bootstrap(address owner, BootstrapFeatures memory features)
                                              public
                                              virtual
                                              returns (bytes4 success)
                                          {
                                              // Deploy and migrate the initial features.
                                              // Order matters here.
                                              // Initialize Registry.
                                              LibBootstrap.delegatecallBootstrapFunction(
                                                  address(features.registry),
                                                  abi.encodeWithSelector(
                                                      SimpleFunctionRegistry.bootstrap.selector
                                                  )
                                              );
                                              // Initialize Ownable.
                                              LibBootstrap.delegatecallBootstrapFunction(
                                                  address(features.ownable),
                                                  abi.encodeWithSelector(
                                                      Ownable.bootstrap.selector
                                                  )
                                              );
                                              // De-register `SimpleFunctionRegistry._extendSelf`.
                                              SimpleFunctionRegistry(address(this)).rollback(
                                                  SimpleFunctionRegistry._extendSelf.selector,
                                                  address(0)
                                              );
                                              // Transfer ownership to the real owner.
                                              Ownable(address(this)).transferOwnership(owner);
                                              success = LibBootstrap.BOOTSTRAP_SUCCESS;
                                          }
                                          /// @dev Self-destructs this contract. Only callable by this contract.
                                          /// @param ethRecipient Who to transfer outstanding ETH to.
                                          function die(address payable ethRecipient) public virtual {
                                              require(msg.sender == _implementation, "InitialMigration/INVALID_SENDER");
                                              selfdestruct(ethRecipient);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
                                      import "../errors/LibTransformERC20RichErrors.sol";
                                      import "./Transformer.sol";
                                      import "./LibERC20Transformer.sol";
                                      /// @dev A transformer that transfers tokens to arbitrary addresses.
                                      contract AffiliateFeeTransformer is
                                          Transformer
                                      {
                                          // solhint-disable no-empty-blocks
                                          using LibRichErrorsV06 for bytes;
                                          using LibSafeMathV06 for uint256;
                                          using LibERC20Transformer for IERC20TokenV06;
                                          /// @dev Information for a single fee.
                                          struct TokenFee {
                                              // The token to transfer to `recipient`.
                                              IERC20TokenV06 token;
                                              // Amount of each `token` to transfer to `recipient`.
                                              // If `amount == uint256(-1)`, the entire balance of `token` will be
                                              // transferred.
                                              uint256 amount;
                                              // Recipient of `token`.
                                              address payable recipient;
                                          }
                                          uint256 private constant MAX_UINT256 = uint256(-1);
                                          /// @dev Create this contract.
                                          constructor()
                                              public
                                              Transformer()
                                          {}
                                          /// @dev Transfers tokens to recipients.
                                          /// @param data ABI-encoded `TokenFee[]`, indicating which tokens to transfer.
                                          /// @return success The success bytes (`LibERC20Transformer.TRANSFORMER_SUCCESS`).
                                          function transform(
                                              bytes32, // callDataHash,
                                              address payable, // taker,
                                              bytes calldata data
                                          )
                                              external
                                              override
                                              returns (bytes4 success)
                                          {
                                              TokenFee[] memory fees = abi.decode(data, (TokenFee[]));
                                              // Transfer tokens to recipients.
                                              for (uint256 i = 0; i < fees.length; ++i) {
                                                  uint256 amount = fees[i].amount;
                                                  if (amount == MAX_UINT256) {
                                                      amount = LibERC20Transformer.getTokenBalanceOf(fees[i].token, address(this));
                                                  }
                                                  if (amount != 0) {
                                                      fees[i].token.transformerTransfer(fees[i].recipient, amount);
                                                  }
                                              }
                                              return LibERC20Transformer.TRANSFORMER_SUCCESS;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibTransformERC20RichErrors.sol";
                                      import "./IERC20Transformer.sol";
                                      /// @dev Abstract base class for transformers.
                                      abstract contract Transformer is
                                          IERC20Transformer
                                      {
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev The address of the deployer.
                                          address public immutable deployer;
                                          /// @dev The original address of this contract.
                                          address private immutable _implementation;
                                          /// @dev Create this contract.
                                          constructor() public {
                                              deployer = msg.sender;
                                              _implementation = address(this);
                                          }
                                          /// @dev Destruct this contract. Only callable by the deployer and will not
                                          ///      succeed in the context of a delegatecall (from another contract).
                                          /// @param ethRecipient The recipient of ETH held in this contract.
                                          function die(address payable ethRecipient)
                                              external
                                              virtual
                                          {
                                              // Only the deployer can call this.
                                              if (msg.sender != deployer) {
                                                  LibTransformERC20RichErrors
                                                      .OnlyCallableByDeployerError(msg.sender, deployer)
                                                      .rrevert();
                                              }
                                              // Must be executing our own context.
                                              if (address(this) != _implementation) {
                                                  LibTransformERC20RichErrors
                                                      .InvalidExecutionContextError(address(this), _implementation)
                                                      .rrevert();
                                              }
                                              selfdestruct(ethRecipient);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibMathV06.sol";
                                      import "../errors/LibTransformERC20RichErrors.sol";
                                      import "../vendor/v3/IExchange.sol";
                                      import "./Transformer.sol";
                                      import "./LibERC20Transformer.sol";
                                      /// @dev A transformer that fills an ERC20 market sell/buy quote.
                                      contract FillQuoteTransformer is
                                          Transformer
                                      {
                                          using LibERC20TokenV06 for IERC20TokenV06;
                                          using LibERC20Transformer for IERC20TokenV06;
                                          using LibSafeMathV06 for uint256;
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev Whether we are performing a market sell or buy.
                                          enum Side {
                                              Sell,
                                              Buy
                                          }
                                          /// @dev Transform data to ABI-encode and pass into `transform()`.
                                          struct TransformData {
                                              // Whether we aer performing a market sell or buy.
                                              Side side;
                                              // The token being sold.
                                              // This should be an actual token, not the ETH pseudo-token.
                                              IERC20TokenV06 sellToken;
                                              // The token being bought.
                                              // This should be an actual token, not the ETH pseudo-token.
                                              IERC20TokenV06 buyToken;
                                              // The orders to fill.
                                              IExchange.Order[] orders;
                                              // Signatures for each respective order in `orders`.
                                              bytes[] signatures;
                                              // Maximum fill amount for each order. This may be shorter than the
                                              // number of orders, where missing entries will be treated as `uint256(-1)`.
                                              // For sells, this will be the maximum sell amount (taker asset).
                                              // For buys, this will be the maximum buy amount (maker asset).
                                              uint256[] maxOrderFillAmounts;
                                              // Amount of `sellToken` to sell or `buyToken` to buy.
                                              // For sells, this may be `uint256(-1)` to sell the entire balance of
                                              // `sellToken`.
                                              uint256 fillAmount;
                                          }
                                          /// @dev Results of a call to `_fillOrder()`.
                                          struct FillOrderResults {
                                              // The amount of taker tokens sold, according to balance checks.
                                              uint256 takerTokenSoldAmount;
                                              // The amount of maker tokens sold, according to balance checks.
                                              uint256 makerTokenBoughtAmount;
                                              // The amount of protocol fee paid.
                                              uint256 protocolFeePaid;
                                          }
                                          /// @dev The Exchange ERC20Proxy ID.
                                          bytes4 private constant ERC20_ASSET_PROXY_ID = 0xf47261b0;
                                          /// @dev Maximum uint256 value.
                                          uint256 private constant MAX_UINT256 = uint256(-1);
                                          /// @dev The Exchange contract.
                                          IExchange public immutable exchange;
                                          /// @dev The ERC20Proxy address.
                                          address public immutable erc20Proxy;
                                          /// @dev Create this contract.
                                          /// @param exchange_ The Exchange V3 instance.
                                          constructor(IExchange exchange_)
                                              public
                                              Transformer()
                                          {
                                              exchange = exchange_;
                                              erc20Proxy = exchange_.getAssetProxy(ERC20_ASSET_PROXY_ID);
                                          }
                                          /// @dev Sell this contract's entire balance of of `sellToken` in exchange
                                          ///      for `buyToken` by filling `orders`. Protocol fees should be attached
                                          ///      to this call. `buyToken` and excess ETH will be transferred back to the caller.
                                          /// @param data_ ABI-encoded `TransformData`.
                                          /// @return success The success bytes (`LibERC20Transformer.TRANSFORMER_SUCCESS`).
                                          function transform(
                                              bytes32, // callDataHash,
                                              address payable, // taker,
                                              bytes calldata data_
                                          )
                                              external
                                              override
                                              returns (bytes4 success)
                                          {
                                              TransformData memory data = abi.decode(data_, (TransformData));
                                              // Validate data fields.
                                              if (data.sellToken.isTokenETH() || data.buyToken.isTokenETH()) {
                                                  LibTransformERC20RichErrors.InvalidTransformDataError(
                                                      LibTransformERC20RichErrors.InvalidTransformDataErrorCode.INVALID_TOKENS,
                                                      data_
                                                  ).rrevert();
                                              }
                                              if (data.orders.length != data.signatures.length) {
                                                  LibTransformERC20RichErrors.InvalidTransformDataError(
                                                      LibTransformERC20RichErrors.InvalidTransformDataErrorCode.INVALID_ARRAY_LENGTH,
                                                      data_
                                                  ).rrevert();
                                              }
                                              if (data.side == Side.Sell && data.fillAmount == MAX_UINT256) {
                                                  // If `sellAmount == -1 then we are selling
                                                  // the entire balance of `sellToken`. This is useful in cases where
                                                  // the exact sell amount is not exactly known in advance, like when
                                                  // unwrapping Chai/cUSDC/cDAI.
                                                  data.fillAmount = data.sellToken.getTokenBalanceOf(address(this));
                                              }
                                              // Approve the ERC20 proxy to spend `sellToken`.
                                              data.sellToken.approveIfBelow(erc20Proxy, data.fillAmount);
                                              // Fill the orders.
                                              uint256 singleProtocolFee = exchange.protocolFeeMultiplier().safeMul(tx.gasprice);
                                              uint256 ethRemaining = address(this).balance;
                                              uint256 boughtAmount = 0;
                                              uint256 soldAmount = 0;
                                              for (uint256 i = 0; i < data.orders.length; ++i) {
                                                  // Check if we've hit our targets.
                                                  if (data.side == Side.Sell) {
                                                      // Market sell check.
                                                      if (soldAmount >= data.fillAmount) {
                                                          break;
                                                      }
                                                  } else {
                                                      // Market buy check.
                                                      if (boughtAmount >= data.fillAmount) {
                                                          break;
                                                      }
                                                  }
                                                  // Ensure we have enough ETH to cover the protocol fee.
                                                  if (ethRemaining < singleProtocolFee) {
                                                      LibTransformERC20RichErrors
                                                          .InsufficientProtocolFeeError(ethRemaining, singleProtocolFee)
                                                          .rrevert();
                                                  }
                                                  // Fill the order.
                                                  FillOrderResults memory results;
                                                  if (data.side == Side.Sell) {
                                                      // Market sell.
                                                      results = _sellToOrder(
                                                          data.buyToken,
                                                          data.sellToken,
                                                          data.orders[i],
                                                          data.signatures[i],
                                                          data.fillAmount.safeSub(soldAmount).min256(
                                                              data.maxOrderFillAmounts.length > i
                                                              ? data.maxOrderFillAmounts[i]
                                                              : MAX_UINT256
                                                          ),
                                                          singleProtocolFee
                                                      );
                                                  } else {
                                                      // Market buy.
                                                      results = _buyFromOrder(
                                                          data.buyToken,
                                                          data.sellToken,
                                                          data.orders[i],
                                                          data.signatures[i],
                                                          data.fillAmount.safeSub(boughtAmount).min256(
                                                              data.maxOrderFillAmounts.length > i
                                                              ? data.maxOrderFillAmounts[i]
                                                              : MAX_UINT256
                                                          ),
                                                          singleProtocolFee
                                                      );
                                                  }
                                                  // Accumulate totals.
                                                  soldAmount = soldAmount.safeAdd(results.takerTokenSoldAmount);
                                                  boughtAmount = boughtAmount.safeAdd(results.makerTokenBoughtAmount);
                                                  ethRemaining = ethRemaining.safeSub(results.protocolFeePaid);
                                              }
                                              // Ensure we hit our targets.
                                              if (data.side == Side.Sell) {
                                                  // Market sell check.
                                                  if (soldAmount < data.fillAmount) {
                                                      LibTransformERC20RichErrors
                                                          .IncompleteFillSellQuoteError(
                                                              address(data.sellToken),
                                                              soldAmount,
                                                              data.fillAmount
                                                          ).rrevert();
                                                  }
                                              } else {
                                                  // Market buy check.
                                                  if (boughtAmount < data.fillAmount) {
                                                      LibTransformERC20RichErrors
                                                          .IncompleteFillBuyQuoteError(
                                                              address(data.buyToken),
                                                              boughtAmount,
                                                              data.fillAmount
                                                          ).rrevert();
                                                  }
                                              }
                                              return LibERC20Transformer.TRANSFORMER_SUCCESS;
                                          }
                                          /// @dev Try to sell up to `sellAmount` from an order.
                                          /// @param makerToken The maker/buy token.
                                          /// @param takerToken The taker/sell token.
                                          /// @param order The order to fill.
                                          /// @param signature The signature for `order`.
                                          /// @param sellAmount Amount of taker token to sell.
                                          /// @param protocolFee The protocol fee needed to fill `order`.
                                          function _sellToOrder(
                                              IERC20TokenV06 makerToken,
                                              IERC20TokenV06 takerToken,
                                              IExchange.Order memory order,
                                              bytes memory signature,
                                              uint256 sellAmount,
                                              uint256 protocolFee
                                          )
                                              private
                                              returns (FillOrderResults memory results)
                                          {
                                              IERC20TokenV06 takerFeeToken =
                                                  _getTokenFromERC20AssetData(order.takerFeeAssetData);
                                              uint256 takerTokenFillAmount = sellAmount;
                                              if (order.takerFee != 0) {
                                                  if (takerFeeToken == makerToken) {
                                                      // Taker fee is payable in the maker token, so we need to
                                                      // approve the proxy to spend the maker token.
                                                      // It isn't worth computing the actual taker fee
                                                      // since `approveIfBelow()` will set the allowance to infinite. We
                                                      // just need a reasonable upper bound to avoid unnecessarily re-approving.
                                                      takerFeeToken.approveIfBelow(erc20Proxy, order.takerFee);
                                                  } else if (takerFeeToken == takerToken){
                                                      // Taker fee is payable in the taker token, so we need to
                                                      // reduce the fill amount to cover the fee.
                                                      // takerTokenFillAmount' =
                                                      //   (takerTokenFillAmount * order.takerAssetAmount) /
                                                      //   (order.takerAssetAmount + order.takerFee)
                                                      takerTokenFillAmount = LibMathV06.getPartialAmountCeil(
                                                          order.takerAssetAmount,
                                                          order.takerAssetAmount.safeAdd(order.takerFee),
                                                          sellAmount
                                                      );
                                                  } else {
                                                      //  Only support taker or maker asset denominated taker fees.
                                                      LibTransformERC20RichErrors.InvalidTakerFeeTokenError(
                                                          address(takerFeeToken)
                                                      ).rrevert();
                                                  }
                                              }
                                              // Clamp fill amount to order size.
                                              takerTokenFillAmount = LibSafeMathV06.min256(
                                                  takerTokenFillAmount,
                                                  order.takerAssetAmount
                                              );
                                              // Perform the fill.
                                              return _fillOrder(
                                                  order,
                                                  signature,
                                                  takerTokenFillAmount,
                                                  protocolFee,
                                                  makerToken,
                                                  takerFeeToken == takerToken
                                              );
                                          }
                                          /// @dev Try to buy up to `buyAmount` from an order.
                                          /// @param makerToken The maker/buy token.
                                          /// @param takerToken The taker/sell token.
                                          /// @param order The order to fill.
                                          /// @param signature The signature for `order`.
                                          /// @param buyAmount Amount of maker token to buy.
                                          /// @param protocolFee The protocol fee needed to fill `order`.
                                          function _buyFromOrder(
                                              IERC20TokenV06 makerToken,
                                              IERC20TokenV06 takerToken,
                                              IExchange.Order memory order,
                                              bytes memory signature,
                                              uint256 buyAmount,
                                              uint256 protocolFee
                                          )
                                              private
                                              returns (FillOrderResults memory results)
                                          {
                                              IERC20TokenV06 takerFeeToken =
                                                  _getTokenFromERC20AssetData(order.takerFeeAssetData);
                                              // Compute the default taker token fill amount.
                                              uint256 takerTokenFillAmount = LibMathV06.getPartialAmountCeil(
                                                  buyAmount,
                                                  order.makerAssetAmount,
                                                  order.takerAssetAmount
                                              );
                                              if (order.takerFee != 0) {
                                                  if (takerFeeToken == makerToken) {
                                                      // Taker fee is payable in the maker token.
                                                      // Adjust the taker token fill amount to account for maker
                                                      // tokens being lost to the taker fee.
                                                      // takerTokenFillAmount' =
                                                      //  (order.takerAssetAmount * buyAmount) /
                                                      //  (order.makerAssetAmount - order.takerFee)
                                                      takerTokenFillAmount = LibMathV06.getPartialAmountCeil(
                                                          buyAmount,
                                                          order.makerAssetAmount.safeSub(order.takerFee),
                                                          order.takerAssetAmount
                                                      );
                                                      // Approve the proxy to spend the maker token.
                                                      // It isn't worth computing the actual taker fee
                                                      // since `approveIfBelow()` will set the allowance to infinite. We
                                                      // just need a reasonable upper bound to avoid unnecessarily re-approving.
                                                      takerFeeToken.approveIfBelow(erc20Proxy, order.takerFee);
                                                  } else if (takerFeeToken != takerToken) {
                                                      //  Only support taker or maker asset denominated taker fees.
                                                      LibTransformERC20RichErrors.InvalidTakerFeeTokenError(
                                                          address(takerFeeToken)
                                                      ).rrevert();
                                                  }
                                              }
                                              // Clamp to order size.
                                              takerTokenFillAmount = LibSafeMathV06.min256(
                                                  order.takerAssetAmount,
                                                  takerTokenFillAmount
                                              );
                                              // Perform the fill.
                                              return _fillOrder(
                                                  order,
                                                  signature,
                                                  takerTokenFillAmount,
                                                  protocolFee,
                                                  makerToken,
                                                  takerFeeToken == takerToken
                                              );
                                          }
                                          /// @dev Attempt to fill an order. If the fill reverts, the revert will be
                                          ///      swallowed and `results` will be zeroed out.
                                          /// @param order The order to fill.
                                          /// @param signature The order signature.
                                          /// @param takerAssetFillAmount How much taker asset to fill.
                                          /// @param protocolFee The protocol fee needed to fill this order.
                                          /// @param makerToken The maker token.
                                          /// @param isTakerFeeInTakerToken Whether the taker fee token is the same as the
                                          ///        taker token.
                                          function _fillOrder(
                                              IExchange.Order memory order,
                                              bytes memory signature,
                                              uint256 takerAssetFillAmount,
                                              uint256 protocolFee,
                                              IERC20TokenV06 makerToken,
                                              bool isTakerFeeInTakerToken
                                          )
                                              private
                                              returns (FillOrderResults memory results)
                                          {
                                              // Track changes in the maker token balance.
                                              uint256 initialMakerTokenBalance = makerToken.balanceOf(address(this));
                                              try
                                                  exchange.fillOrder
                                                      {value: protocolFee}
                                                      (order, takerAssetFillAmount, signature)
                                                  returns (IExchange.FillResults memory fillResults)
                                              {
                                                  // Update maker quantity based on changes in token balances.
                                                  results.makerTokenBoughtAmount = makerToken.balanceOf(address(this))
                                                      .safeSub(initialMakerTokenBalance);
                                                  // We can trust the other fill result quantities.
                                                  results.protocolFeePaid = fillResults.protocolFeePaid;
                                                  results.takerTokenSoldAmount = fillResults.takerAssetFilledAmount;
                                                  // If the taker fee is payable in the taker asset, include the
                                                  // taker fee in the total amount sold.
                                                  if (isTakerFeeInTakerToken) {
                                                      results.takerTokenSoldAmount =
                                                          results.takerTokenSoldAmount.safeAdd(fillResults.takerFeePaid);
                                                  }
                                              } catch (bytes memory) {
                                                  // Swallow failures, leaving all results as zero.
                                              }
                                          }
                                          /// @dev Extract the token from plain ERC20 asset data.
                                          ///      If the asset-data is empty, a zero token address will be returned.
                                          /// @param assetData The order asset data.
                                          function _getTokenFromERC20AssetData(bytes memory assetData)
                                              private
                                              pure
                                              returns (IERC20TokenV06 token)
                                          {
                                              if (assetData.length == 0) {
                                                  return IERC20TokenV06(address(0));
                                              }
                                              if (assetData.length != 36 ||
                                                  LibBytesV06.readBytes4(assetData, 0) != ERC20_ASSET_PROXY_ID)
                                              {
                                                  LibTransformERC20RichErrors
                                                      .InvalidERC20AssetDataError(assetData)
                                                      .rrevert();
                                              }
                                              return IERC20TokenV06(LibBytesV06.readAddress(assetData, 16));
                                          }
                                      }
                                      /*
                                        Copyright 2019 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./LibSafeMathV06.sol";
                                      import "./errors/LibRichErrorsV06.sol";
                                      import "./errors/LibMathRichErrorsV06.sol";
                                      library LibMathV06 {
                                          using LibSafeMathV06 for uint256;
                                          /// @dev Calculates partial value given a numerator and denominator rounded down.
                                          ///      Reverts if rounding error is >= 0.1%
                                          /// @param numerator Numerator.
                                          /// @param denominator Denominator.
                                          /// @param target Value to calculate partial of.
                                          /// @return partialAmount Partial value of target rounded down.
                                          function safeGetPartialAmountFloor(
                                              uint256 numerator,
                                              uint256 denominator,
                                              uint256 target
                                          )
                                              internal
                                              pure
                                              returns (uint256 partialAmount)
                                          {
                                              if (isRoundingErrorFloor(
                                                      numerator,
                                                      denominator,
                                                      target
                                              )) {
                                                  LibRichErrorsV06.rrevert(LibMathRichErrorsV06.RoundingError(
                                                      numerator,
                                                      denominator,
                                                      target
                                                  ));
                                              }
                                              partialAmount = numerator.safeMul(target).safeDiv(denominator);
                                              return partialAmount;
                                          }
                                          /// @dev Calculates partial value given a numerator and denominator rounded down.
                                          ///      Reverts if rounding error is >= 0.1%
                                          /// @param numerator Numerator.
                                          /// @param denominator Denominator.
                                          /// @param target Value to calculate partial of.
                                          /// @return partialAmount Partial value of target rounded up.
                                          function safeGetPartialAmountCeil(
                                              uint256 numerator,
                                              uint256 denominator,
                                              uint256 target
                                          )
                                              internal
                                              pure
                                              returns (uint256 partialAmount)
                                          {
                                              if (isRoundingErrorCeil(
                                                      numerator,
                                                      denominator,
                                                      target
                                              )) {
                                                  LibRichErrorsV06.rrevert(LibMathRichErrorsV06.RoundingError(
                                                      numerator,
                                                      denominator,
                                                      target
                                                  ));
                                              }
                                              // safeDiv computes `floor(a / b)`. We use the identity (a, b integer):
                                              //       ceil(a / b) = floor((a + b - 1) / b)
                                              // To implement `ceil(a / b)` using safeDiv.
                                              partialAmount = numerator.safeMul(target)
                                                  .safeAdd(denominator.safeSub(1))
                                                  .safeDiv(denominator);
                                              return partialAmount;
                                          }
                                          /// @dev Calculates partial value given a numerator and denominator rounded down.
                                          /// @param numerator Numerator.
                                          /// @param denominator Denominator.
                                          /// @param target Value to calculate partial of.
                                          /// @return partialAmount Partial value of target rounded down.
                                          function getPartialAmountFloor(
                                              uint256 numerator,
                                              uint256 denominator,
                                              uint256 target
                                          )
                                              internal
                                              pure
                                              returns (uint256 partialAmount)
                                          {
                                              partialAmount = numerator.safeMul(target).safeDiv(denominator);
                                              return partialAmount;
                                          }
                                          /// @dev Calculates partial value given a numerator and denominator rounded down.
                                          /// @param numerator Numerator.
                                          /// @param denominator Denominator.
                                          /// @param target Value to calculate partial of.
                                          /// @return partialAmount Partial value of target rounded up.
                                          function getPartialAmountCeil(
                                              uint256 numerator,
                                              uint256 denominator,
                                              uint256 target
                                          )
                                              internal
                                              pure
                                              returns (uint256 partialAmount)
                                          {
                                              // safeDiv computes `floor(a / b)`. We use the identity (a, b integer):
                                              //       ceil(a / b) = floor((a + b - 1) / b)
                                              // To implement `ceil(a / b)` using safeDiv.
                                              partialAmount = numerator.safeMul(target)
                                                  .safeAdd(denominator.safeSub(1))
                                                  .safeDiv(denominator);
                                              return partialAmount;
                                          }
                                          /// @dev Checks if rounding error >= 0.1% when rounding down.
                                          /// @param numerator Numerator.
                                          /// @param denominator Denominator.
                                          /// @param target Value to multiply with numerator/denominator.
                                          /// @return isError Rounding error is present.
                                          function isRoundingErrorFloor(
                                              uint256 numerator,
                                              uint256 denominator,
                                              uint256 target
                                          )
                                              internal
                                              pure
                                              returns (bool isError)
                                          {
                                              if (denominator == 0) {
                                                  LibRichErrorsV06.rrevert(LibMathRichErrorsV06.DivisionByZeroError());
                                              }
                                              // The absolute rounding error is the difference between the rounded
                                              // value and the ideal value. The relative rounding error is the
                                              // absolute rounding error divided by the absolute value of the
                                              // ideal value. This is undefined when the ideal value is zero.
                                              //
                                              // The ideal value is `numerator * target / denominator`.
                                              // Let's call `numerator * target % denominator` the remainder.
                                              // The absolute error is `remainder / denominator`.
                                              //
                                              // When the ideal value is zero, we require the absolute error to
                                              // be zero. Fortunately, this is always the case. The ideal value is
                                              // zero iff `numerator == 0` and/or `target == 0`. In this case the
                                              // remainder and absolute error are also zero.
                                              if (target == 0 || numerator == 0) {
                                                  return false;
                                              }
                                              // Otherwise, we want the relative rounding error to be strictly
                                              // less than 0.1%.
                                              // The relative error is `remainder / (numerator * target)`.
                                              // We want the relative error less than 1 / 1000:
                                              //        remainder / (numerator * denominator)  <  1 / 1000
                                              // or equivalently:
                                              //        1000 * remainder  <  numerator * target
                                              // so we have a rounding error iff:
                                              //        1000 * remainder  >=  numerator * target
                                              uint256 remainder = mulmod(
                                                  target,
                                                  numerator,
                                                  denominator
                                              );
                                              isError = remainder.safeMul(1000) >= numerator.safeMul(target);
                                              return isError;
                                          }
                                          /// @dev Checks if rounding error >= 0.1% when rounding up.
                                          /// @param numerator Numerator.
                                          /// @param denominator Denominator.
                                          /// @param target Value to multiply with numerator/denominator.
                                          /// @return isError Rounding error is present.
                                          function isRoundingErrorCeil(
                                              uint256 numerator,
                                              uint256 denominator,
                                              uint256 target
                                          )
                                              internal
                                              pure
                                              returns (bool isError)
                                          {
                                              if (denominator == 0) {
                                                  LibRichErrorsV06.rrevert(LibMathRichErrorsV06.DivisionByZeroError());
                                              }
                                              // See the comments in `isRoundingError`.
                                              if (target == 0 || numerator == 0) {
                                                  // When either is zero, the ideal value and rounded value are zero
                                                  // and there is no rounding error. (Although the relative error
                                                  // is undefined.)
                                                  return false;
                                              }
                                              // Compute remainder as before
                                              uint256 remainder = mulmod(
                                                  target,
                                                  numerator,
                                                  denominator
                                              );
                                              remainder = denominator.safeSub(remainder) % denominator;
                                              isError = remainder.safeMul(1000) >= numerator.safeMul(target);
                                              return isError;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibMathRichErrorsV06 {
                                          // bytes4(keccak256("DivisionByZeroError()"))
                                          bytes internal constant DIVISION_BY_ZERO_ERROR =
                                              hex"a791837c";
                                          // bytes4(keccak256("RoundingError(uint256,uint256,uint256)"))
                                          bytes4 internal constant ROUNDING_ERROR_SELECTOR =
                                              0x339f3de2;
                                          // solhint-disable func-name-mixedcase
                                          function DivisionByZeroError()
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return DIVISION_BY_ZERO_ERROR;
                                          }
                                          function RoundingError(
                                              uint256 numerator,
                                              uint256 denominator,
                                              uint256 target
                                          )
                                              internal
                                              pure
                                              returns (bytes memory)
                                          {
                                              return abi.encodeWithSelector(
                                                  ROUNDING_ERROR_SELECTOR,
                                                  numerator,
                                                  denominator,
                                                  target
                                              );
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Interface to the V3 Exchange.
                                      interface IExchange {
                                          /// @dev V3 Order structure.
                                          struct Order {
                                              // Address that created the order.
                                              address makerAddress;
                                              // Address that is allowed to fill the order.
                                              // If set to 0, any address is allowed to fill the order.
                                              address takerAddress;
                                              // Address that will recieve fees when order is filled.
                                              address feeRecipientAddress;
                                              // Address that is allowed to call Exchange contract methods that affect this order.
                                              // If set to 0, any address is allowed to call these methods.
                                              address senderAddress;
                                              // Amount of makerAsset being offered by maker. Must be greater than 0.
                                              uint256 makerAssetAmount;
                                              // Amount of takerAsset being bid on by maker. Must be greater than 0.
                                              uint256 takerAssetAmount;
                                              // Fee paid to feeRecipient by maker when order is filled.
                                              uint256 makerFee;
                                              // Fee paid to feeRecipient by taker when order is filled.
                                              uint256 takerFee;
                                              // Timestamp in seconds at which order expires.
                                              uint256 expirationTimeSeconds;
                                              // Arbitrary number to facilitate uniqueness of the order's hash.
                                              uint256 salt;
                                              // Encoded data that can be decoded by a specified proxy contract when transferring makerAsset.
                                              // The leading bytes4 references the id of the asset proxy.
                                              bytes makerAssetData;
                                              // Encoded data that can be decoded by a specified proxy contract when transferring takerAsset.
                                              // The leading bytes4 references the id of the asset proxy.
                                              bytes takerAssetData;
                                              // Encoded data that can be decoded by a specified proxy contract when transferring makerFeeAsset.
                                              // The leading bytes4 references the id of the asset proxy.
                                              bytes makerFeeAssetData;
                                              // Encoded data that can be decoded by a specified proxy contract when transferring takerFeeAsset.
                                              // The leading bytes4 references the id of the asset proxy.
                                              bytes takerFeeAssetData;
                                          }
                                          /// @dev V3 `fillOrder()` results.`
                                          struct FillResults {
                                              // Total amount of makerAsset(s) filled.
                                              uint256 makerAssetFilledAmount;
                                              // Total amount of takerAsset(s) filled.
                                              uint256 takerAssetFilledAmount;
                                              // Total amount of fees paid by maker(s) to feeRecipient(s).
                                              uint256 makerFeePaid;
                                              // Total amount of fees paid by taker to feeRecipients(s).
                                              uint256 takerFeePaid;
                                              // Total amount of fees paid by taker to the staking contract.
                                              uint256 protocolFeePaid;
                                          }
                                          /// @dev Fills the input order.
                                          /// @param order Order struct containing order specifications.
                                          /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
                                          /// @param signature Proof that order has been created by maker.
                                          /// @return fillResults Amounts filled and fees paid by maker and taker.
                                          function fillOrder(
                                              Order calldata order,
                                              uint256 takerAssetFillAmount,
                                              bytes calldata signature
                                          )
                                              external
                                              payable
                                              returns (FillResults memory fillResults);
                                          /// @dev Returns the protocolFeeMultiplier
                                          /// @return multiplier The multiplier for protocol fees.
                                          function protocolFeeMultiplier()
                                              external
                                              view
                                              returns (uint256 multiplier);
                                          /// @dev Gets an asset proxy.
                                          /// @param assetProxyId Id of the asset proxy.
                                          /// @return proxyAddress The asset proxy registered to assetProxyId.
                                          ///         Returns 0x0 if no proxy is registered.
                                          function getAssetProxy(bytes4 assetProxyId)
                                              external
                                              view
                                              returns (address proxyAddress);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
                                      import "../errors/LibTransformERC20RichErrors.sol";
                                      import "./Transformer.sol";
                                      import "./LibERC20Transformer.sol";
                                      /// @dev A transformer that transfers tokens to the taker.
                                      contract PayTakerTransformer is
                                          Transformer
                                      {
                                          // solhint-disable no-empty-blocks
                                          using LibRichErrorsV06 for bytes;
                                          using LibSafeMathV06 for uint256;
                                          using LibERC20Transformer for IERC20TokenV06;
                                          /// @dev Transform data to ABI-encode and pass into `transform()`.
                                          struct TransformData {
                                              // The tokens to transfer to the taker.
                                              IERC20TokenV06[] tokens;
                                              // Amount of each token in `tokens` to transfer to the taker.
                                              // `uint(-1)` will transfer the entire balance.
                                              uint256[] amounts;
                                          }
                                          /// @dev Maximum uint256 value.
                                          uint256 private constant MAX_UINT256 = uint256(-1);
                                          /// @dev Create this contract.
                                          constructor()
                                              public
                                              Transformer()
                                          {}
                                          /// @dev Forwards tokens to the taker.
                                          /// @param taker The taker address (caller of `TransformERC20.transformERC20()`).
                                          /// @param data_ ABI-encoded `TransformData`, indicating which tokens to transfer.
                                          /// @return success The success bytes (`LibERC20Transformer.TRANSFORMER_SUCCESS`).
                                          function transform(
                                              bytes32, // callDataHash,
                                              address payable taker,
                                              bytes calldata data_
                                          )
                                              external
                                              override
                                              returns (bytes4 success)
                                          {
                                              TransformData memory data = abi.decode(data_, (TransformData));
                                              // Transfer tokens directly to the taker.
                                              for (uint256 i = 0; i < data.tokens.length; ++i) {
                                                  // The `amounts` array can be shorter than the `tokens` array.
                                                  // Missing elements are treated as `uint256(-1)`.
                                                  uint256 amount = data.amounts.length > i ? data.amounts[i] : uint256(-1);
                                                  if (amount == MAX_UINT256) {
                                                      amount = data.tokens[i].getTokenBalanceOf(address(this));
                                                  }
                                                  if (amount != 0) {
                                                      data.tokens[i].transformerTransfer(taker, amount);
                                                  }
                                              }
                                              return LibERC20Transformer.TRANSFORMER_SUCCESS;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/IEtherTokenV06.sol";
                                      import "../errors/LibTransformERC20RichErrors.sol";
                                      import "./Transformer.sol";
                                      import "./LibERC20Transformer.sol";
                                      /// @dev A transformer that wraps or unwraps WETH.
                                      contract WethTransformer is
                                          Transformer
                                      {
                                          using LibRichErrorsV06 for bytes;
                                          using LibSafeMathV06 for uint256;
                                          using LibERC20Transformer for IERC20TokenV06;
                                          /// @dev Transform data to ABI-encode and pass into `transform()`.
                                          struct TransformData {
                                              // The token to wrap/unwrap. Must be either ETH or WETH.
                                              IERC20TokenV06 token;
                                              // Amount of `token` to wrap or unwrap.
                                              // `uint(-1)` will unwrap the entire balance.
                                              uint256 amount;
                                          }
                                          /// @dev The WETH contract address.
                                          IEtherTokenV06 public immutable weth;
                                          /// @dev Maximum uint256 value.
                                          uint256 private constant MAX_UINT256 = uint256(-1);
                                          /// @dev Construct the transformer and store the WETH address in an immutable.
                                          /// @param weth_ The weth token.
                                          constructor(IEtherTokenV06 weth_)
                                              public
                                              Transformer()
                                          {
                                              weth = weth_;
                                          }
                                          /// @dev Wraps and unwraps WETH.
                                          /// @param data_ ABI-encoded `TransformData`, indicating which token to wrap/umwrap.
                                          /// @return success The success bytes (`LibERC20Transformer.TRANSFORMER_SUCCESS`).
                                          function transform(
                                              bytes32, // callDataHash,
                                              address payable, // taker,
                                              bytes calldata data_
                                          )
                                              external
                                              override
                                              returns (bytes4 success)
                                          {
                                              TransformData memory data = abi.decode(data_, (TransformData));
                                              if (!data.token.isTokenETH() && data.token != weth) {
                                                  LibTransformERC20RichErrors.InvalidTransformDataError(
                                                      LibTransformERC20RichErrors.InvalidTransformDataErrorCode.INVALID_TOKENS,
                                                      data_
                                                  ).rrevert();
                                              }
                                              uint256 amount = data.amount;
                                              if (amount == MAX_UINT256) {
                                                  amount = data.token.getTokenBalanceOf(address(this));
                                              }
                                              if (amount != 0) {
                                                  if (data.token.isTokenETH()) {
                                                      // Wrap ETH.
                                                      weth.deposit{value: amount}();
                                                  } else {
                                                      // Unwrap WETH.
                                                      weth.withdraw(amount);
                                                  }
                                              }
                                              return LibERC20Transformer.TRANSFORMER_SUCCESS;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./IERC20TokenV06.sol";
                                      interface IEtherTokenV06 is
                                          IERC20TokenV06
                                      {
                                          /// @dev Wrap ether.
                                          function deposit() external payable;
                                          /// @dev Unwrap ether.
                                          function withdraw(uint256 amount) external;
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      interface ITestSimpleFunctionRegistryFeature {
                                          function testFn() external view returns (uint256 id);
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      contract TestCallTarget {
                                          event CallTargetCalled(
                                              address context,
                                              address sender,
                                              bytes data,
                                              uint256 value
                                          );
                                          bytes4 private constant MAGIC_BYTES = 0x12345678;
                                          bytes private constant REVERTING_DATA = hex"1337";
                                          fallback() external payable {
                                              if (keccak256(msg.data) == keccak256(REVERTING_DATA)) {
                                                  revert("TestCallTarget/REVERT");
                                              }
                                              emit CallTargetCalled(
                                                  address(this),
                                                  msg.sender,
                                                  msg.data,
                                                  msg.value
                                              );
                                              bytes4 rval = MAGIC_BYTES;
                                              assembly {
                                                  mstore(0, rval)
                                                  return(0, 32)
                                              }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      contract TestDelegateCaller {
                                          function executeDelegateCall(
                                              address target,
                                              bytes calldata callData
                                          )
                                              external
                                          {
                                              (bool success, bytes memory resultData) = target.delegatecall(callData);
                                              if (!success) {
                                                  assembly { revert(add(resultData, 32), mload(resultData)) }
                                              }
                                              assembly { return(add(resultData, 32), mload(resultData)) }
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibMathV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../src/vendor/v3/IExchange.sol";
                                      import "./TestMintableERC20Token.sol";
                                      contract TestFillQuoteTransformerExchange {
                                          struct FillBehavior {
                                              // How much of the order is filled, in taker asset amount.
                                              uint256 filledTakerAssetAmount;
                                              // Scaling for maker assets minted, in 1e18.
                                              uint256 makerAssetMintRatio;
                                          }
                                          uint256 private constant PROTOCOL_FEE_MULTIPLIER = 1337;
                                          using LibSafeMathV06 for uint256;
                                          function fillOrder(
                                              IExchange.Order calldata order,
                                              uint256 takerAssetFillAmount,
                                              bytes calldata signature
                                          )
                                              external
                                              payable
                                              returns (IExchange.FillResults memory fillResults)
                                          {
                                              require(
                                                  signature.length != 0,
                                                  "TestFillQuoteTransformerExchange/INVALID_SIGNATURE"
                                              );
                                              // The signature is the ABI-encoded FillBehavior data.
                                              FillBehavior memory behavior = abi.decode(signature, (FillBehavior));
                                              uint256 protocolFee = PROTOCOL_FEE_MULTIPLIER * tx.gasprice;
                                              require(
                                                  msg.value == protocolFee,
                                                  "TestFillQuoteTransformerExchange/INSUFFICIENT_PROTOCOL_FEE"
                                              );
                                              // Return excess protocol fee.
                                              msg.sender.transfer(msg.value - protocolFee);
                                              // Take taker tokens.
                                              TestMintableERC20Token takerToken = _getTokenFromAssetData(order.takerAssetData);
                                              takerAssetFillAmount = LibSafeMathV06.min256(
                                                  order.takerAssetAmount.safeSub(behavior.filledTakerAssetAmount),
                                                  takerAssetFillAmount
                                              );
                                              require(
                                                  takerToken.getSpendableAmount(msg.sender, address(this)) >= takerAssetFillAmount,
                                                  "TestFillQuoteTransformerExchange/INSUFFICIENT_TAKER_FUNDS"
                                              );
                                              takerToken.transferFrom(msg.sender, order.makerAddress, takerAssetFillAmount);
                                              // Mint maker tokens.
                                              uint256 makerAssetFilledAmount = LibMathV06.getPartialAmountFloor(
                                                  takerAssetFillAmount,
                                                  order.takerAssetAmount,
                                                  order.makerAssetAmount
                                              );
                                              TestMintableERC20Token makerToken = _getTokenFromAssetData(order.makerAssetData);
                                              makerToken.mint(
                                                  msg.sender,
                                                  LibMathV06.getPartialAmountFloor(
                                                      behavior.makerAssetMintRatio,
                                                      1e18,
                                                      makerAssetFilledAmount
                                                  )
                                              );
                                              // Take taker fee.
                                              TestMintableERC20Token takerFeeToken = _getTokenFromAssetData(order.takerFeeAssetData);
                                              uint256 takerFee = LibMathV06.getPartialAmountFloor(
                                                  takerAssetFillAmount,
                                                  order.takerAssetAmount,
                                                  order.takerFee
                                              );
                                              require(
                                                  takerFeeToken.getSpendableAmount(msg.sender, address(this)) >= takerFee,
                                                  "TestFillQuoteTransformerExchange/INSUFFICIENT_TAKER_FEE_FUNDS"
                                              );
                                              takerFeeToken.transferFrom(msg.sender, order.feeRecipientAddress, takerFee);
                                              fillResults.makerAssetFilledAmount = makerAssetFilledAmount;
                                              fillResults.takerAssetFilledAmount = takerAssetFillAmount;
                                              fillResults.makerFeePaid = uint256(-1);
                                              fillResults.takerFeePaid = takerFee;
                                              fillResults.protocolFeePaid = protocolFee;
                                          }
                                          function encodeBehaviorData(FillBehavior calldata behavior)
                                              external
                                              pure
                                              returns (bytes memory encoded)
                                          {
                                              return abi.encode(behavior);
                                          }
                                          function protocolFeeMultiplier()
                                              external
                                              pure
                                              returns (uint256)
                                          {
                                              return PROTOCOL_FEE_MULTIPLIER;
                                          }
                                          function getAssetProxy(bytes4)
                                              external
                                              view
                                              returns (address)
                                          {
                                              return address(this);
                                          }
                                          function _getTokenFromAssetData(bytes memory assetData)
                                              private
                                              pure
                                              returns (TestMintableERC20Token token)
                                          {
                                              return TestMintableERC20Token(LibBytesV06.readAddress(assetData, 16));
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      contract TestMintableERC20Token {
                                          mapping(address => uint256) public balanceOf;
                                          mapping(address => mapping(address => uint256)) public allowance;
                                          function transfer(address to, uint256 amount)
                                              external
                                              virtual
                                              returns (bool)
                                          {
                                              return transferFrom(msg.sender, to, amount);
                                          }
                                          function approve(address spender, uint256 amount)
                                              external
                                              virtual
                                              returns (bool)
                                          {
                                              allowance[msg.sender][spender] = amount;
                                              return true;
                                          }
                                          function mint(address owner, uint256 amount)
                                              external
                                              virtual
                                          {
                                              balanceOf[owner] += amount;
                                          }
                                          function burn(address owner, uint256 amount)
                                              external
                                              virtual
                                          {
                                              require(balanceOf[owner] >= amount, "TestMintableERC20Token/INSUFFICIENT_FUNDS");
                                              balanceOf[owner] -= amount;
                                          }
                                          function transferFrom(address from, address to, uint256 amount)
                                              public
                                              virtual
                                              returns (bool)
                                          {
                                              if (from != msg.sender) {
                                                  require(
                                                      allowance[from][msg.sender] >= amount,
                                                      "TestMintableERC20Token/INSUFFICIENT_ALLOWANCE"
                                                  );
                                                  allowance[from][msg.sender] -= amount;
                                              }
                                              require(balanceOf[from] >= amount, "TestMintableERC20Token/INSUFFICIENT_FUNDS");
                                              balanceOf[from] -= amount;
                                              balanceOf[to] += amount;
                                              return true;
                                          }
                                          function getSpendableAmount(address owner, address spender)
                                              external
                                              view
                                              returns (uint256)
                                          {
                                              return balanceOf[owner] < allowance[owner][spender]
                                                  ? balanceOf[owner]
                                                  : allowance[owner][spender];
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/transformers/IERC20Transformer.sol";
                                      import "./TestMintableERC20Token.sol";
                                      import "./TestTransformerHost.sol";
                                      contract TestFillQuoteTransformerHost is
                                          TestTransformerHost
                                      {
                                          function executeTransform(
                                              IERC20Transformer transformer,
                                              TestMintableERC20Token inputToken,
                                              uint256 inputTokenAmount,
                                              bytes calldata data
                                          )
                                              external
                                              payable
                                          {
                                              if (inputTokenAmount != 0) {
                                                  inputToken.mint(address(this), inputTokenAmount);
                                              }
                                              // Have to make this call externally because transformers aren't payable.
                                              this.rawExecuteTransform(transformer, bytes32(0), msg.sender, data);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "../src/transformers/IERC20Transformer.sol";
                                      import "../src/transformers/LibERC20Transformer.sol";
                                      contract TestTransformerHost {
                                          using LibERC20Transformer for IERC20TokenV06;
                                          using LibRichErrorsV06 for bytes;
                                          function rawExecuteTransform(
                                              IERC20Transformer transformer,
                                              bytes32 callDataHash,
                                              address taker,
                                              bytes calldata data
                                          )
                                              external
                                          {
                                              (bool _success, bytes memory resultData) =
                                                  address(transformer).delegatecall(abi.encodeWithSelector(
                                                      transformer.transform.selector,
                                                      callDataHash,
                                                      taker,
                                                      data
                                                  ));
                                              if (!_success) {
                                                  resultData.rrevert();
                                              }
                                              require(
                                                  abi.decode(resultData, (bytes4)) == LibERC20Transformer.TRANSFORMER_SUCCESS,
                                                  "TestTransformerHost/INVALID_TRANSFORMER_RESULT"
                                              );
                                          }
                                          // solhint-disable
                                          receive() external payable {}
                                          // solhint-enable
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/ZeroEx.sol";
                                      import "../src/features/IBootstrap.sol";
                                      import "../src/migrations/FullMigration.sol";
                                      contract TestFullMigration is
                                          FullMigration
                                      {
                                          address public dieRecipient;
                                          // solhint-disable-next-line no-empty-blocks
                                          constructor(address payable deployer) public FullMigration(deployer) {}
                                          function die(address payable ethRecipient) external override {
                                              dieRecipient = ethRecipient;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/ZeroEx.sol";
                                      import "../src/features/IBootstrap.sol";
                                      import "../src/migrations/InitialMigration.sol";
                                      contract TestInitialMigration is
                                          InitialMigration
                                      {
                                          address public bootstrapFeature;
                                          address public dieRecipient;
                                          // solhint-disable-next-line no-empty-blocks
                                          constructor(address deployer) public InitialMigration(deployer) {}
                                          function callBootstrap(ZeroEx zeroEx) external {
                                              IBootstrap(address(zeroEx)).bootstrap(address(this), new bytes(0));
                                          }
                                          function bootstrap(address owner, BootstrapFeatures memory features)
                                              public
                                              override
                                              returns (bytes4 success)
                                          {
                                              success = InitialMigration.bootstrap(owner, features);
                                              // Snoop the bootstrap feature contract.
                                              bootstrapFeature = ZeroEx(address(uint160(address(this))))
                                                  .getFunctionImplementation(IBootstrap.bootstrap.selector);
                                          }
                                          function die(address payable ethRecipient) public override {
                                              dieRecipient = ethRecipient;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/migrations/LibMigrate.sol";
                                      import "../src/features/IOwnable.sol";
                                      contract TestMigrator {
                                          event TestMigrateCalled(
                                              bytes callData,
                                              address owner
                                          );
                                          function succeedingMigrate() external returns (bytes4 success) {
                                              emit TestMigrateCalled(
                                                  msg.data,
                                                  IOwnable(address(this)).owner()
                                              );
                                              return LibMigrate.MIGRATE_SUCCESS;
                                          }
                                          function failingMigrate() external returns (bytes4 success) {
                                              emit TestMigrateCalled(
                                                  msg.data,
                                                  IOwnable(address(this)).owner()
                                              );
                                              return 0xdeadbeef;
                                          }
                                          function revertingMigrate() external pure {
                                              revert("OOPSIE");
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
                                      import "../src/transformers/IERC20Transformer.sol";
                                      import "../src/transformers/LibERC20Transformer.sol";
                                      import "./TestMintableERC20Token.sol";
                                      contract TestMintTokenERC20Transformer is
                                          IERC20Transformer
                                      {
                                          struct TransformData {
                                              IERC20TokenV06 inputToken;
                                              TestMintableERC20Token outputToken;
                                              uint256 burnAmount;
                                              uint256 mintAmount;
                                              uint256 feeAmount;
                                          }
                                          event MintTransform(
                                              address context,
                                              address caller,
                                              bytes32 callDataHash,
                                              address taker,
                                              bytes data,
                                              uint256 inputTokenBalance,
                                              uint256 ethBalance
                                          );
                                          function transform(
                                              bytes32 callDataHash,
                                              address payable taker,
                                              bytes calldata data_
                                          )
                                              external
                                              override
                                              returns (bytes4 success)
                                          {
                                              TransformData memory data = abi.decode(data_, (TransformData));
                                              emit MintTransform(
                                                  address(this),
                                                  msg.sender,
                                                  callDataHash,
                                                  taker,
                                                  data_,
                                                  data.inputToken.balanceOf(address(this)),
                                                  address(this).balance
                                              );
                                              // "Burn" input tokens.
                                              data.inputToken.transfer(address(0), data.burnAmount);
                                              // Mint output tokens.
                                              if (LibERC20Transformer.isTokenETH(IERC20TokenV06(address(data.outputToken)))) {
                                                  taker.transfer(data.mintAmount);
                                              } else {
                                                  data.outputToken.mint(
                                                      taker,
                                                      data.mintAmount
                                                  );
                                                  // Burn fees from output.
                                                  data.outputToken.burn(taker, data.feeAmount);
                                              }
                                              return LibERC20Transformer.TRANSFORMER_SUCCESS;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/fixins/FixinCommon.sol";
                                      contract TestSimpleFunctionRegistryFeatureImpl1 is
                                          FixinCommon
                                      {
                                          function testFn()
                                              external
                                              pure
                                              returns (uint256 id)
                                          {
                                              return 1337;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/fixins/FixinCommon.sol";
                                      contract TestSimpleFunctionRegistryFeatureImpl2 is
                                          FixinCommon
                                      {
                                          function testFn()
                                              external
                                              pure
                                              returns (uint256 id)
                                          {
                                              return 1338;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/features/TokenSpender.sol";
                                      contract TestTokenSpender is
                                          TokenSpender
                                      {
                                          modifier onlySelf() override {
                                              _;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "./TestMintableERC20Token.sol";
                                      contract TestTokenSpenderERC20Token is
                                          TestMintableERC20Token
                                      {
                                          event TransferFromCalled(
                                              address sender,
                                              address from,
                                              address to,
                                              uint256 amount
                                          );
                                          // `transferFrom()` behavior depends on the value of `amount`.
                                          uint256 constant private EMPTY_RETURN_AMOUNT = 1337;
                                          uint256 constant private FALSE_RETURN_AMOUNT = 1338;
                                          uint256 constant private REVERT_RETURN_AMOUNT = 1339;
                                          function transferFrom(address from, address to, uint256 amount)
                                              public
                                              override
                                              returns (bool)
                                          {
                                              emit TransferFromCalled(msg.sender, from, to, amount);
                                              if (amount == EMPTY_RETURN_AMOUNT) {
                                                  assembly { return(0, 0) }
                                              }
                                              if (amount == FALSE_RETURN_AMOUNT) {
                                                  return false;
                                              }
                                              if (amount == REVERT_RETURN_AMOUNT) {
                                                  revert("TestTokenSpenderERC20Token/Revert");
                                              }
                                              return true;
                                          }
                                          function setBalanceAndAllowanceOf(
                                              address owner,
                                              uint256 balance,
                                              address spender,
                                              uint256 allowance_
                                          )
                                              external
                                          {
                                              balanceOf[owner] = balance;
                                              allowance[owner][spender] = allowance_;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/features/TransformERC20.sol";
                                      contract TestTransformERC20 is
                                          TransformERC20
                                      {
                                          // solhint-disable no-empty-blocks
                                          constructor()
                                              TransformERC20()
                                              public
                                          {}
                                          modifier onlySelf() override {
                                              _;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/transformers/Transformer.sol";
                                      import "../src/transformers/LibERC20Transformer.sol";
                                      contract TestTransformerBase is
                                          Transformer
                                      {
                                          function transform(
                                              bytes32,
                                              address payable,
                                              bytes calldata
                                          )
                                              external
                                              override
                                              returns (bytes4 success)
                                          {
                                              return LibERC20Transformer.TRANSFORMER_SUCCESS;
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/transformers/LibERC20Transformer.sol";
                                      contract TestTransformerDeployerTransformer {
                                          address payable public immutable deployer;
                                          constructor() public payable {
                                              deployer = msg.sender;
                                          }
                                          modifier onlyDeployer() {
                                              require(msg.sender == deployer, "TestTransformerDeployerTransformer/ONLY_DEPLOYER");
                                              _;
                                          }
                                          function die()
                                              external
                                              onlyDeployer
                                          {
                                              selfdestruct(deployer);
                                          }
                                          function isDeployedByDeployer(uint32 nonce)
                                              external
                                              view
                                              returns (bool)
                                          {
                                              return LibERC20Transformer.getDeployedAddress(deployer, nonce) == address(this);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "./TestMintableERC20Token.sol";
                                      contract TestWeth is
                                          TestMintableERC20Token
                                      {
                                          function deposit()
                                              external
                                              payable
                                          {
                                              this.mint(msg.sender, msg.value);
                                          }
                                          function withdraw(uint256 amount)
                                              external
                                          {
                                              require(balanceOf[msg.sender] >= amount, "TestWeth/INSUFFICIENT_FUNDS");
                                              balanceOf[msg.sender] -= amount;
                                              msg.sender.transfer(amount);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/transformers/IERC20Transformer.sol";
                                      import "./TestMintableERC20Token.sol";
                                      import "./TestTransformerHost.sol";
                                      import "./TestWeth.sol";
                                      contract TestWethTransformerHost is
                                          TestTransformerHost
                                      {
                                          // solhint-disable
                                          TestWeth private immutable _weth;
                                          // solhint-enable
                                          constructor(TestWeth weth) public {
                                              _weth = weth;
                                          }
                                          function executeTransform(
                                              uint256 wethAmount,
                                              IERC20Transformer transformer,
                                              bytes calldata data
                                          )
                                              external
                                              payable
                                          {
                                              if (wethAmount != 0) {
                                                  _weth.deposit{value: wethAmount}();
                                              }
                                              // Have to make this call externally because transformers aren't payable.
                                              this.rawExecuteTransform(transformer, bytes32(0), msg.sender, data);
                                          }
                                      }
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../src/fixins/FixinCommon.sol";
                                      import "../src/ZeroEx.sol";
                                      contract TestZeroExFeature is
                                          FixinCommon
                                      {
                                          event PayableFnCalled(uint256 value);
                                          event NotPayableFnCalled();
                                          function payableFn()
                                              external
                                              payable
                                          {
                                              emit PayableFnCalled(msg.value);
                                          }
                                          function notPayableFn()
                                              external
                                          {
                                              emit NotPayableFnCalled();
                                          }
                                          // solhint-disable no-empty-blocks
                                          function unimplmentedFn()
                                              external
                                          {}
                                          function internalFn()
                                              external
                                              onlySelf
                                          {}
                                      }
                                      

                                      File 6 of 11: WETH9
                                      // Copyright (C) 2015, 2016, 2017 Dapphub
                                      
                                      // This program is free software: you can redistribute it and/or modify
                                      // it under the terms of the GNU General Public License as published by
                                      // the Free Software Foundation, either version 3 of the License, or
                                      // (at your option) any later version.
                                      
                                      // This program is distributed in the hope that it will be useful,
                                      // but WITHOUT ANY WARRANTY; without even the implied warranty of
                                      // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                                      // GNU General Public License for more details.
                                      
                                      // You should have received a copy of the GNU General Public License
                                      // along with this program.  If not, see <http://www.gnu.org/licenses/>.
                                      
                                      pragma solidity ^0.4.18;
                                      
                                      contract WETH9 {
                                          string public name     = "Wrapped Ether";
                                          string public symbol   = "WETH";
                                          uint8  public decimals = 18;
                                      
                                          event  Approval(address indexed src, address indexed guy, uint wad);
                                          event  Transfer(address indexed src, address indexed dst, uint wad);
                                          event  Deposit(address indexed dst, uint wad);
                                          event  Withdrawal(address indexed src, uint wad);
                                      
                                          mapping (address => uint)                       public  balanceOf;
                                          mapping (address => mapping (address => uint))  public  allowance;
                                      
                                          function() public payable {
                                              deposit();
                                          }
                                          function deposit() public payable {
                                              balanceOf[msg.sender] += msg.value;
                                              Deposit(msg.sender, msg.value);
                                          }
                                          function withdraw(uint wad) public {
                                              require(balanceOf[msg.sender] >= wad);
                                              balanceOf[msg.sender] -= wad;
                                              msg.sender.transfer(wad);
                                              Withdrawal(msg.sender, wad);
                                          }
                                      
                                          function totalSupply() public view returns (uint) {
                                              return this.balance;
                                          }
                                      
                                          function approve(address guy, uint wad) public returns (bool) {
                                              allowance[msg.sender][guy] = wad;
                                              Approval(msg.sender, guy, wad);
                                              return true;
                                          }
                                      
                                          function transfer(address dst, uint wad) public returns (bool) {
                                              return transferFrom(msg.sender, dst, wad);
                                          }
                                      
                                          function transferFrom(address src, address dst, uint wad)
                                              public
                                              returns (bool)
                                          {
                                              require(balanceOf[src] >= wad);
                                      
                                              if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
                                                  require(allowance[src][msg.sender] >= wad);
                                                  allowance[src][msg.sender] -= wad;
                                              }
                                      
                                              balanceOf[src] -= wad;
                                              balanceOf[dst] += wad;
                                      
                                              Transfer(src, dst, wad);
                                      
                                              return true;
                                          }
                                      }
                                      
                                      
                                      /*
                                                          GNU GENERAL PUBLIC LICENSE
                                                             Version 3, 29 June 2007
                                      
                                       Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
                                       Everyone is permitted to copy and distribute verbatim copies
                                       of this license document, but changing it is not allowed.
                                      
                                                                  Preamble
                                      
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                                      software and other kinds of works.
                                      
                                        The licenses for most software and other practical works are designed
                                      to take away your freedom to share and change the works.  By contrast,
                                      the GNU General Public License is intended to guarantee your freedom to
                                      share and change all versions of a program--to make sure it remains free
                                      software for all its users.  We, the Free Software Foundation, use the
                                      GNU General Public License for most of our software; it applies also to
                                      any other work released this way by its authors.  You can apply it to
                                      your programs, too.
                                      
                                        When we speak of free software, we are referring to freedom, not
                                      price.  Our General Public Licenses are designed to make sure that you
                                      have the freedom to distribute copies of free software (and charge for
                                      them if you wish), that you receive source code or can get it if you
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                                      */

                                      File 7 of 11: AdminUpgradeabilityProxy
                                      /**
                                       *Submitted for verification at Etherscan.io on 2018-10-22
                                      */
                                      
                                      pragma solidity ^0.4.24;
                                      
                                      // File: contracts/upgradeability/Proxy.sol
                                      
                                      /**
                                       * @title Proxy
                                       * @dev Implements delegation of calls to other contracts, with proper
                                       * forwarding of return values and bubbling of failures.
                                       * It defines a fallback function that delegates all calls to the address
                                       * returned by the abstract _implementation() internal function.
                                       */
                                      contract Proxy {
                                        /**
                                         * @dev Fallback function.
                                         * Implemented entirely in `_fallback`.
                                         */
                                        function () payable external {
                                          _fallback();
                                        }
                                      
                                        /**
                                         * @return The Address of the implementation.
                                         */
                                        function _implementation() internal view returns (address);
                                      
                                        /**
                                         * @dev Delegates execution to an implementation contract.
                                         * This is a low level function that doesn't return to its internal call site.
                                         * It will return to the external caller whatever the implementation returns.
                                         * @param implementation Address to delegate.
                                         */
                                        function _delegate(address implementation) internal {
                                          assembly {
                                            // Copy msg.data. We take full control of memory in this inline assembly
                                            // block because it will not return to Solidity code. We overwrite the
                                            // Solidity scratch pad at memory position 0.
                                            calldatacopy(0, 0, calldatasize)
                                      
                                            // Call the implementation.
                                            // out and outsize are 0 because we don't know the size yet.
                                            let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)
                                      
                                            // Copy the returned data.
                                            returndatacopy(0, 0, returndatasize)
                                      
                                            switch result
                                            // delegatecall returns 0 on error.
                                            case 0 { revert(0, returndatasize) }
                                            default { return(0, returndatasize) }
                                          }
                                        }
                                      
                                        /**
                                         * @dev Function that is run as the first thing in the fallback function.
                                         * Can be redefined in derived contracts to add functionality.
                                         * Redefinitions must call super._willFallback().
                                         */
                                        function _willFallback() internal {
                                        }
                                      
                                        /**
                                         * @dev fallback implementation.
                                         * Extracted to enable manual triggering.
                                         */
                                        function _fallback() internal {
                                          _willFallback();
                                          _delegate(_implementation());
                                        }
                                      }
                                      
                                      // File: openzeppelin-solidity/contracts/AddressUtils.sol
                                      
                                      /**
                                       * Utility library of inline functions on addresses
                                       */
                                      library AddressUtils {
                                      
                                        /**
                                         * Returns whether the target address is a contract
                                         * @dev This function will return false if invoked during the constructor of a contract,
                                         *  as the code is not actually created until after the constructor finishes.
                                         * @param addr address to check
                                         * @return whether the target address is a contract
                                         */
                                        function isContract(address addr) internal view returns (bool) {
                                          uint256 size;
                                          // XXX Currently there is no better way to check if there is a contract in an address
                                          // than to check the size of the code at that address.
                                          // See https://ethereum.stackexchange.com/a/14016/36603
                                          // for more details about how this works.
                                          // TODO Check this again before the Serenity release, because all addresses will be
                                          // contracts then.
                                          // solium-disable-next-line security/no-inline-assembly
                                          assembly { size := extcodesize(addr) }
                                          return size > 0;
                                        }
                                      
                                      }
                                      
                                      // File: contracts/upgradeability/UpgradeabilityProxy.sol
                                      
                                      /**
                                       * @title UpgradeabilityProxy
                                       * @dev This contract implements a proxy that allows to change the
                                       * implementation address to which it will delegate.
                                       * Such a change is called an implementation upgrade.
                                       */
                                      contract UpgradeabilityProxy is Proxy {
                                        /**
                                         * @dev Emitted when the implementation is upgraded.
                                         * @param implementation Address of the new implementation.
                                         */
                                        event Upgraded(address indexed implementation);
                                      
                                        /**
                                         * @dev Storage slot with the address of the current implementation.
                                         * This is the keccak-256 hash of "org.zeppelinos.proxy.implementation", and is
                                         * validated in the constructor.
                                         */
                                        bytes32 private constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;
                                      
                                        /**
                                         * @dev Contract constructor.
                                         * @param _implementation Address of the initial implementation.
                                         * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
                                         * It should include the signature and the parameters of the function to be called, as described in
                                         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
                                         * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
                                         */
                                        constructor(address _implementation, bytes _data) public payable {
                                          assert(IMPLEMENTATION_SLOT == keccak256("org.zeppelinos.proxy.implementation"));
                                          _setImplementation(_implementation);
                                          if(_data.length > 0) {
                                            require(_implementation.delegatecall(_data));
                                          }
                                        }
                                      
                                        /**
                                         * @dev Returns the current implementation.
                                         * @return Address of the current implementation
                                         */
                                        function _implementation() internal view returns (address impl) {
                                          bytes32 slot = IMPLEMENTATION_SLOT;
                                          assembly {
                                            impl := sload(slot)
                                          }
                                        }
                                      
                                        /**
                                         * @dev Upgrades the proxy to a new implementation.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function _upgradeTo(address newImplementation) internal {
                                          _setImplementation(newImplementation);
                                          emit Upgraded(newImplementation);
                                        }
                                      
                                        /**
                                         * @dev Sets the implementation address of the proxy.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function _setImplementation(address newImplementation) private {
                                          require(AddressUtils.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");
                                      
                                          bytes32 slot = IMPLEMENTATION_SLOT;
                                      
                                          assembly {
                                            sstore(slot, newImplementation)
                                          }
                                        }
                                      }
                                      
                                      // File: contracts/upgradeability/AdminUpgradeabilityProxy.sol
                                      
                                      /**
                                       * @title AdminUpgradeabilityProxy
                                       * @dev This contract combines an upgradeability proxy with an authorization
                                       * mechanism for administrative tasks.
                                       * All external functions in this contract must be guarded by the
                                       * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
                                       * feature proposal that would enable this to be done automatically.
                                       */
                                      contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
                                        /**
                                         * @dev Emitted when the administration has been transferred.
                                         * @param previousAdmin Address of the previous admin.
                                         * @param newAdmin Address of the new admin.
                                         */
                                        event AdminChanged(address previousAdmin, address newAdmin);
                                      
                                        /**
                                         * @dev Storage slot with the admin of the contract.
                                         * This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
                                         * validated in the constructor.
                                         */
                                        bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;
                                      
                                        /**
                                         * @dev Modifier to check whether the `msg.sender` is the admin.
                                         * If it is, it will run the function. Otherwise, it will delegate the call
                                         * to the implementation.
                                         */
                                        modifier ifAdmin() {
                                          if (msg.sender == _admin()) {
                                            _;
                                          } else {
                                            _fallback();
                                          }
                                        }
                                      
                                        /**
                                         * Contract constructor.
                                         * It sets the `msg.sender` as the proxy administrator.
                                         * @param _implementation address of the initial implementation.
                                         * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
                                         * It should include the signature and the parameters of the function to be called, as described in
                                         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
                                         * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
                                         */
                                        constructor(address _implementation, bytes _data) UpgradeabilityProxy(_implementation, _data) public payable {
                                          assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));
                                      
                                          _setAdmin(msg.sender);
                                        }
                                      
                                        /**
                                         * @return The address of the proxy admin.
                                         */
                                        function admin() external view ifAdmin returns (address) {
                                          return _admin();
                                        }
                                      
                                        /**
                                         * @return The address of the implementation.
                                         */
                                        function implementation() external view ifAdmin returns (address) {
                                          return _implementation();
                                        }
                                      
                                        /**
                                         * @dev Changes the admin of the proxy.
                                         * Only the current admin can call this function.
                                         * @param newAdmin Address to transfer proxy administration to.
                                         */
                                        function changeAdmin(address newAdmin) external ifAdmin {
                                          require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
                                          emit AdminChanged(_admin(), newAdmin);
                                          _setAdmin(newAdmin);
                                        }
                                      
                                        /**
                                         * @dev Upgrade the backing implementation of the proxy.
                                         * Only the admin can call this function.
                                         * @param newImplementation Address of the new implementation.
                                         */
                                        function upgradeTo(address newImplementation) external ifAdmin {
                                          _upgradeTo(newImplementation);
                                        }
                                      
                                        /**
                                         * @dev Upgrade the backing implementation of the proxy and call a function
                                         * on the new implementation.
                                         * This is useful to initialize the proxied contract.
                                         * @param newImplementation Address of the new implementation.
                                         * @param data Data to send as msg.data in the low level call.
                                         * It should include the signature and the parameters of the function to be called, as described in
                                         * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
                                         */
                                        function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
                                          _upgradeTo(newImplementation);
                                          require(newImplementation.delegatecall(data));
                                        }
                                      
                                        /**
                                         * @return The admin slot.
                                         */
                                        function _admin() internal view returns (address adm) {
                                          bytes32 slot = ADMIN_SLOT;
                                          assembly {
                                            adm := sload(slot)
                                          }
                                        }
                                      
                                        /**
                                         * @dev Sets the address of the proxy admin.
                                         * @param newAdmin Address of the new proxy admin.
                                         */
                                        function _setAdmin(address newAdmin) internal {
                                          bytes32 slot = ADMIN_SLOT;
                                      
                                          assembly {
                                            sstore(slot, newAdmin)
                                          }
                                        }
                                      
                                        /**
                                         * @dev Only fall back when the sender is not the admin.
                                         */
                                        function _willFallback() internal {
                                          require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
                                          super._willFallback();
                                        }
                                      }

                                      File 8 of 11: ZeroDAOToken
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.3;
                                      // Slight modifiations from base Open Zeppelin Contracts
                                      // Consult /oz/README.md for more information
                                      import "./oz/ERC20Upgradeable.sol";
                                      import "./oz/ERC20SnapshotUpgradeable.sol";
                                      import "./oz/ERC20PausableUpgradeable.sol";
                                      import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
                                      contract ZeroDAOToken is
                                        OwnableUpgradeable,
                                        ERC20Upgradeable,
                                        ERC20PausableUpgradeable,
                                        ERC20SnapshotUpgradeable
                                      {
                                        event AuthorizedSnapshotter(address account);
                                        event DeauthorizedSnapshotter(address account);
                                        // Mapping which stores all addresses allowed to snapshot
                                        mapping(address => bool) authorizedToSnapshot;
                                        function initialize(string memory name, string memory symbol)
                                          public
                                          initializer
                                        {
                                          __Ownable_init();
                                          __ERC20_init(name, symbol);
                                          __ERC20Snapshot_init();
                                          __ERC20Pausable_init();
                                        }
                                        // Call this on the implementation contract (not the proxy)
                                        function initializeImplementation() public initializer {
                                          __Ownable_init();
                                          _pause();
                                        }
                                        /**
                                         * Mints new tokens.
                                         * @param account the account to mint the tokens for
                                         * @param amount the amount of tokens to mint.
                                         */
                                        function mint(address account, uint256 amount) external onlyOwner {
                                          _mint(account, amount);
                                        }
                                        /**
                                         * Burns tokens from an address.
                                         * @param account the account to mint the tokens for
                                         * @param amount the amount of tokens to mint.
                                         */
                                        function burn(address account, uint256 amount) external onlyOwner {
                                          _burn(account, amount);
                                        }
                                        /**
                                         * Pauses the token contract preventing any token mint/transfer/burn operations.
                                         * Can only be called if the contract is unpaused.
                                         */
                                        function pause() external onlyOwner {
                                          _pause();
                                        }
                                        /**
                                         * Unpauses the token contract preventing any token mint/transfer/burn operations
                                         * Can only be called if the contract is paused.
                                         */
                                        function unpause() external onlyOwner {
                                          _unpause();
                                        }
                                        /**
                                         * Creates a token balance snapshot. Ideally this would be called by the
                                         * controlling DAO whenever a proposal is made.
                                         */
                                        function snapshot() external returns (uint256) {
                                          require(
                                            authorizedToSnapshot[_msgSender()] || _msgSender() == owner(),
                                            "zDAOToken: Not authorized to snapshot"
                                          );
                                          return _snapshot();
                                        }
                                        /**
                                         * Authorizes an account to take snapshots
                                         * @param account The account to authorize
                                         */
                                        function authorizeSnapshotter(address account) external onlyOwner {
                                          require(
                                            !authorizedToSnapshot[account],
                                            "zDAOToken: Account already authorized"
                                          );
                                          authorizedToSnapshot[account] = true;
                                          emit AuthorizedSnapshotter(account);
                                        }
                                        /**
                                         * Deauthorizes an account to take snapshots
                                         * @param account The account to de-authorize
                                         */
                                        function deauthorizeSnapshotter(address account) external onlyOwner {
                                          require(authorizedToSnapshot[account], "zDAOToken: Account not authorized");
                                          authorizedToSnapshot[account] = false;
                                          emit DeauthorizedSnapshotter(account);
                                        }
                                        /**
                                         * Utility function to transfer tokens to many addresses at once.
                                         * @param recipients The addresses to send tokens to
                                         * @param amount The amount of tokens to send
                                         * @return Boolean if the transfer was a success
                                         */
                                        function transferBulk(address[] calldata recipients, uint256 amount)
                                          external
                                          returns (bool)
                                        {
                                          address sender = _msgSender();
                                          uint256 total = amount * recipients.length;
                                          require(
                                            _balances[sender] >= total,
                                            "ERC20: transfer amount exceeds balance"
                                          );
                                          require(!paused(), "ERC20Pausable: token transfer while paused");
                                          _balances[sender] -= total;
                                          _updateAccountSnapshot(sender);
                                          for (uint256 i = 0; i < recipients.length; ++i) {
                                            address recipient = recipients[i];
                                            require(recipient != address(0), "ERC20: transfer to the zero address");
                                            // Note: _beforeTokenTransfer isn't called here
                                            // This function emulates what it would do (paused and snapshot)
                                            _balances[recipient] += amount;
                                            _updateAccountSnapshot(recipient);
                                            emit Transfer(sender, recipient, amount);
                                          }
                                          return true;
                                        }
                                        /**
                                         * Utility function to transfer tokens to many addresses at once.
                                         * @param sender The address to send the tokens from
                                         * @param recipients The addresses to send tokens to
                                         * @param amount The amount of tokens to send
                                         * @return Boolean if the transfer was a success
                                         */
                                        function transferFromBulk(
                                          address sender,
                                          address[] calldata recipients,
                                          uint256 amount
                                        ) external returns (bool) {
                                          require(!paused(), "ERC20Pausable: token transfer while paused");
                                          uint256 total = amount * recipients.length;
                                          require(
                                            _balances[sender] >= total,
                                            "ERC20: transfer amount exceeds balance"
                                          );
                                          // Ensure enough allowance
                                          uint256 currentAllowance = _allowances[sender][_msgSender()];
                                          require(
                                            currentAllowance >= total,
                                            "ERC20: transfer total exceeds allowance"
                                          );
                                          _approve(sender, _msgSender(), currentAllowance - total);
                                          _balances[sender] -= total;
                                          _updateAccountSnapshot(sender);
                                          for (uint256 i = 0; i < recipients.length; ++i) {
                                            address recipient = recipients[i];
                                            require(recipient != address(0), "ERC20: transfer to the zero address");
                                            // Note: _beforeTokenTransfer isn't called here
                                            // This function emulates what it would do (paused and snapshot)
                                            _balances[recipient] += amount;
                                            _updateAccountSnapshot(recipient);
                                            emit Transfer(sender, recipient, amount);
                                          }
                                          return true;
                                        }
                                        function _beforeTokenTransfer(
                                          address from,
                                          address to,
                                          uint256 amount
                                        )
                                          internal
                                          virtual
                                          override(
                                            ERC20PausableUpgradeable,
                                            ERC20SnapshotUpgradeable,
                                            ERC20Upgradeable
                                          )
                                        {
                                          super._beforeTokenTransfer(from, to, amount);
                                        }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      import "@openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";
                                      import "@openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol";
                                      import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
                                      /**
                                       * @dev Implementation of the {IERC20} interface.
                                       *
                                       * This implementation is agnostic to the way tokens are created. This means
                                       * that a supply mechanism has to be added in a derived contract using {_mint}.
                                       * For a generic mechanism see {ERC20PresetMinterPauser}.
                                       *
                                       * TIP: For a detailed writeup see our guide
                                       * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
                                       * to implement supply mechanisms].
                                       *
                                       * We have followed general OpenZeppelin guidelines: functions revert instead
                                       * of returning `false` on failure. This behavior is nonetheless conventional
                                       * and does not conflict with the expectations of ERC20 applications.
                                       *
                                       * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
                                       * This allows applications to reconstruct the allowance for all accounts just
                                       * by listening to said events. Other implementations of the EIP may not emit
                                       * these events, as it isn't required by the specification.
                                       *
                                       * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
                                       * functions have been added to mitigate the well-known issues around setting
                                       * allowances. See {IERC20-approve}.
                                       */
                                      contract ERC20Upgradeable is
                                        Initializable,
                                        ContextUpgradeable,
                                        IERC20Upgradeable
                                      {
                                        // Diff from Open Zeppelin Standard
                                        mapping(address => uint256) internal _balances;
                                        mapping(address => mapping(address => uint256)) internal _allowances;
                                        uint256 private _totalSupply;
                                        string private _name;
                                        string private _symbol;
                                        /**
                                         * @dev Sets the values for {name} and {symbol}.
                                         *
                                         * The defaut value of {decimals} is 18. To select a different value for
                                         * {decimals} you should overload it.
                                         *
                                         * All three of these values are immutable: they can only be set once during
                                         * construction.
                                         */
                                        function __ERC20_init(string memory name_, string memory symbol_)
                                          internal
                                          initializer
                                        {
                                          __Context_init_unchained();
                                          __ERC20_init_unchained(name_, symbol_);
                                        }
                                        function __ERC20_init_unchained(string memory name_, string memory symbol_)
                                          internal
                                          initializer
                                        {
                                          _name = name_;
                                          _symbol = symbol_;
                                        }
                                        /**
                                         * @dev Returns the name of the token.
                                         */
                                        function name() public view virtual returns (string memory) {
                                          return _name;
                                        }
                                        /**
                                         * @dev Returns the symbol of the token, usually a shorter version of the
                                         * name.
                                         */
                                        function symbol() public view virtual returns (string memory) {
                                          return _symbol;
                                        }
                                        /**
                                         * @dev Returns the number of decimals used to get its user representation.
                                         * For example, if `decimals` equals `2`, a balance of `505` tokens should
                                         * be displayed to a user as `5,05` (`505 / 10 ** 2`).
                                         *
                                         * Tokens usually opt for a value of 18, imitating the relationship between
                                         * Ether and Wei. This is the value {ERC20} uses, unless this function is
                                         * overloaded;
                                         *
                                         * NOTE: This information is only used for _display_ purposes: it in
                                         * no way affects any of the arithmetic of the contract, including
                                         * {IERC20-balanceOf} and {IERC20-transfer}.
                                         */
                                        function decimals() public view virtual returns (uint8) {
                                          return 18;
                                        }
                                        /**
                                         * @dev See {IERC20-totalSupply}.
                                         */
                                        function totalSupply() public view virtual override returns (uint256) {
                                          return _totalSupply;
                                        }
                                        /**
                                         * @dev See {IERC20-balanceOf}.
                                         */
                                        function balanceOf(address account)
                                          public
                                          view
                                          virtual
                                          override
                                          returns (uint256)
                                        {
                                          return _balances[account];
                                        }
                                        /**
                                         * @dev See {IERC20-transfer}.
                                         *
                                         * Requirements:
                                         *
                                         * - `recipient` cannot be the zero address.
                                         * - the caller must have a balance of at least `amount`.
                                         */
                                        function transfer(address recipient, uint256 amount)
                                          public
                                          virtual
                                          override
                                          returns (bool)
                                        {
                                          _transfer(_msgSender(), recipient, amount);
                                          return true;
                                        }
                                        /**
                                         * @dev See {IERC20-allowance}.
                                         */
                                        function allowance(address owner, address spender)
                                          public
                                          view
                                          virtual
                                          override
                                          returns (uint256)
                                        {
                                          return _allowances[owner][spender];
                                        }
                                        /**
                                         * @dev See {IERC20-approve}.
                                         *
                                         * Requirements:
                                         *
                                         * - `spender` cannot be the zero address.
                                         */
                                        function approve(address spender, uint256 amount)
                                          public
                                          virtual
                                          override
                                          returns (bool)
                                        {
                                          _approve(_msgSender(), spender, amount);
                                          return true;
                                        }
                                        /**
                                         * @dev See {IERC20-transferFrom}.
                                         *
                                         * Emits an {Approval} event indicating the updated allowance. This is not
                                         * required by the EIP. See the note at the beginning of {ERC20}.
                                         *
                                         * Requirements:
                                         *
                                         * - `sender` and `recipient` cannot be the zero address.
                                         * - `sender` must have a balance of at least `amount`.
                                         * - the caller must have allowance for ``sender``'s tokens of at least
                                         * `amount`.
                                         */
                                        function transferFrom(
                                          address sender,
                                          address recipient,
                                          uint256 amount
                                        ) public virtual override returns (bool) {
                                          _transfer(sender, recipient, amount);
                                          uint256 currentAllowance = _allowances[sender][_msgSender()];
                                          require(
                                            currentAllowance >= amount,
                                            "ERC20: transfer amount exceeds allowance"
                                          );
                                          _approve(sender, _msgSender(), currentAllowance - amount);
                                          return true;
                                        }
                                        /**
                                         * @dev Atomically increases the allowance granted to `spender` by the caller.
                                         *
                                         * This is an alternative to {approve} that can be used as a mitigation for
                                         * problems described in {IERC20-approve}.
                                         *
                                         * Emits an {Approval} event indicating the updated allowance.
                                         *
                                         * Requirements:
                                         *
                                         * - `spender` cannot be the zero address.
                                         */
                                        function increaseAllowance(address spender, uint256 addedValue)
                                          public
                                          virtual
                                          returns (bool)
                                        {
                                          _approve(
                                            _msgSender(),
                                            spender,
                                            _allowances[_msgSender()][spender] + addedValue
                                          );
                                          return true;
                                        }
                                        /**
                                         * @dev Atomically decreases the allowance granted to `spender` by the caller.
                                         *
                                         * This is an alternative to {approve} that can be used as a mitigation for
                                         * problems described in {IERC20-approve}.
                                         *
                                         * Emits an {Approval} event indicating the updated allowance.
                                         *
                                         * Requirements:
                                         *
                                         * - `spender` cannot be the zero address.
                                         * - `spender` must have allowance for the caller of at least
                                         * `subtractedValue`.
                                         */
                                        function decreaseAllowance(address spender, uint256 subtractedValue)
                                          public
                                          virtual
                                          returns (bool)
                                        {
                                          uint256 currentAllowance = _allowances[_msgSender()][spender];
                                          require(
                                            currentAllowance >= subtractedValue,
                                            "ERC20: decreased allowance below zero"
                                          );
                                          _approve(_msgSender(), spender, currentAllowance - subtractedValue);
                                          return true;
                                        }
                                        /**
                                         * @dev Moves tokens `amount` from `sender` to `recipient`.
                                         *
                                         * This is internal function is equivalent to {transfer}, and can be used to
                                         * e.g. implement automatic token fees, slashing mechanisms, etc.
                                         *
                                         * Emits a {Transfer} event.
                                         *
                                         * Requirements:
                                         *
                                         * - `sender` cannot be the zero address.
                                         * - `recipient` cannot be the zero address.
                                         * - `sender` must have a balance of at least `amount`.
                                         */
                                        function _transfer(
                                          address sender,
                                          address recipient,
                                          uint256 amount
                                        ) internal virtual {
                                          require(sender != address(0), "ERC20: transfer from the zero address");
                                          require(recipient != address(0), "ERC20: transfer to the zero address");
                                          _beforeTokenTransfer(sender, recipient, amount);
                                          uint256 senderBalance = _balances[sender];
                                          require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
                                          _balances[sender] = senderBalance - amount;
                                          _balances[recipient] += amount;
                                          emit Transfer(sender, recipient, amount);
                                        }
                                        /** @dev Creates `amount` tokens and assigns them to `account`, increasing
                                         * the total supply.
                                         *
                                         * Emits a {Transfer} event with `from` set to the zero address.
                                         *
                                         * Requirements:
                                         *
                                         * - `to` cannot be the zero address.
                                         */
                                        function _mint(address account, uint256 amount) internal virtual {
                                          require(account != address(0), "ERC20: mint to the zero address");
                                          _beforeTokenTransfer(address(0), account, amount);
                                          _totalSupply += amount;
                                          _balances[account] += amount;
                                          emit Transfer(address(0), account, amount);
                                        }
                                        /**
                                         * @dev Destroys `amount` tokens from `account`, reducing the
                                         * total supply.
                                         *
                                         * Emits a {Transfer} event with `to` set to the zero address.
                                         *
                                         * Requirements:
                                         *
                                         * - `account` cannot be the zero address.
                                         * - `account` must have at least `amount` tokens.
                                         */
                                        function _burn(address account, uint256 amount) internal virtual {
                                          require(account != address(0), "ERC20: burn from the zero address");
                                          _beforeTokenTransfer(account, address(0), amount);
                                          uint256 accountBalance = _balances[account];
                                          require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
                                          _balances[account] = accountBalance - amount;
                                          _totalSupply -= amount;
                                          emit Transfer(account, address(0), amount);
                                        }
                                        /**
                                         * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
                                         *
                                         * This internal function is equivalent to `approve`, and can be used to
                                         * e.g. set automatic allowances for certain subsystems, etc.
                                         *
                                         * Emits an {Approval} event.
                                         *
                                         * Requirements:
                                         *
                                         * - `owner` cannot be the zero address.
                                         * - `spender` cannot be the zero address.
                                         */
                                        function _approve(
                                          address owner,
                                          address spender,
                                          uint256 amount
                                        ) internal virtual {
                                          require(owner != address(0), "ERC20: approve from the zero address");
                                          require(spender != address(0), "ERC20: approve to the zero address");
                                          _allowances[owner][spender] = amount;
                                          emit Approval(owner, spender, amount);
                                        }
                                        /**
                                         * @dev Hook that is called before any transfer of tokens. This includes
                                         * minting and burning.
                                         *
                                         * Calling conditions:
                                         *
                                         * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
                                         * will be to transferred to `to`.
                                         * - when `from` is zero, `amount` tokens will be minted for `to`.
                                         * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
                                         * - `from` and `to` are never both zero.
                                         *
                                         * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
                                         */
                                        function _beforeTokenTransfer(
                                          address from,
                                          address to,
                                          uint256 amount
                                        ) internal virtual {}
                                        uint256[45] private __gap;
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      import "./ERC20Upgradeable.sol";
                                      import "@openzeppelin/contracts-upgradeable/utils/ArraysUpgradeable.sol";
                                      import "@openzeppelin/contracts-upgradeable/utils/CountersUpgradeable.sol";
                                      import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
                                      /**
                                       * @dev This contract extends an ERC20 token with a snapshot mechanism. When a snapshot is created, the balances and
                                       * total supply at the time are recorded for later access.
                                       *
                                       * This can be used to safely create mechanisms based on token balances such as trustless dividends or weighted voting.
                                       * In naive implementations it's possible to perform a "double spend" attack by reusing the same balance from different
                                       * accounts. By using snapshots to calculate dividends or voting power, those attacks no longer apply. It can also be
                                       * used to create an efficient ERC20 forking mechanism.
                                       *
                                       * Snapshots are created by the internal {_snapshot} function, which will emit the {Snapshot} event and return a
                                       * snapshot id. To get the total supply at the time of a snapshot, call the function {totalSupplyAt} with the snapshot
                                       * id. To get the balance of an account at the time of a snapshot, call the {balanceOfAt} function with the snapshot id
                                       * and the account address.
                                       *
                                       * ==== Gas Costs
                                       *
                                       * Snapshots are efficient. Snapshot creation is _O(1)_. Retrieval of balances or total supply from a snapshot is _O(log
                                       * n)_ in the number of snapshots that have been created, although _n_ for a specific account will generally be much
                                       * smaller since identical balances in subsequent snapshots are stored as a single entry.
                                       *
                                       * There is a constant overhead for normal ERC20 transfers due to the additional snapshot bookkeeping. This overhead is
                                       * only significant for the first transfer that immediately follows a snapshot for a particular account. Subsequent
                                       * transfers will have normal cost until the next snapshot, and so on.
                                       */
                                      abstract contract ERC20SnapshotUpgradeable is Initializable, ERC20Upgradeable {
                                        function __ERC20Snapshot_init() internal initializer {
                                          __Context_init_unchained();
                                          __ERC20Snapshot_init_unchained();
                                        }
                                        function __ERC20Snapshot_init_unchained() internal initializer {}
                                        // Inspired by Jordi Baylina's MiniMeToken to record historical balances:
                                        // https://github.com/Giveth/minimd/blob/ea04d950eea153a04c51fa510b068b9dded390cb/contracts/MiniMeToken.sol
                                        using ArraysUpgradeable for uint256[];
                                        using CountersUpgradeable for CountersUpgradeable.Counter;
                                        // Snapshotted values have arrays of ids and the value corresponding to that id. These could be an array of a
                                        // Snapshot struct, but that would impede usage of functions that work on an array.
                                        struct Snapshots {
                                          uint256[] ids;
                                          uint256[] values;
                                        }
                                        mapping(address => Snapshots) private _accountBalanceSnapshots;
                                        Snapshots private _totalSupplySnapshots;
                                        // Snapshot ids increase monotonically, with the first value being 1. An id of 0 is invalid.
                                        CountersUpgradeable.Counter private _currentSnapshotId;
                                        /**
                                         * @dev Emitted by {_snapshot} when a snapshot identified by `id` is created.
                                         */
                                        event Snapshot(uint256 id);
                                        /**
                                         * @dev Creates a new snapshot and returns its snapshot id.
                                         *
                                         * Emits a {Snapshot} event that contains the same id.
                                         *
                                         * {_snapshot} is `internal` and you have to decide how to expose it externally. Its usage may be restricted to a
                                         * set of accounts, for example using {AccessControl}, or it may be open to the public.
                                         *
                                         * [WARNING]
                                         * ====
                                         * While an open way of calling {_snapshot} is required for certain trust minimization mechanisms such as forking,
                                         * you must consider that it can potentially be used by attackers in two ways.
                                         *
                                         * First, it can be used to increase the cost of retrieval of values from snapshots, although it will grow
                                         * logarithmically thus rendering this attack ineffective in the long term. Second, it can be used to target
                                         * specific accounts and increase the cost of ERC20 transfers for them, in the ways specified in the Gas Costs
                                         * section above.
                                         *
                                         * We haven't measured the actual numbers; if this is something you're interested in please reach out to us.
                                         * ====
                                         */
                                        function _snapshot() internal virtual returns (uint256) {
                                          _currentSnapshotId.increment();
                                          uint256 currentId = _currentSnapshotId.current();
                                          emit Snapshot(currentId);
                                          return currentId;
                                        }
                                        /**
                                         * @dev Retrieves the balance of `account` at the time `snapshotId` was created.
                                         */
                                        function balanceOfAt(address account, uint256 snapshotId)
                                          public
                                          view
                                          virtual
                                          returns (uint256)
                                        {
                                          (bool snapshotted, uint256 value) =
                                            _valueAt(snapshotId, _accountBalanceSnapshots[account]);
                                          return snapshotted ? value : balanceOf(account);
                                        }
                                        /**
                                         * @dev Retrieves the total supply at the time `snapshotId` was created.
                                         */
                                        function totalSupplyAt(uint256 snapshotId)
                                          public
                                          view
                                          virtual
                                          returns (uint256)
                                        {
                                          (bool snapshotted, uint256 value) =
                                            _valueAt(snapshotId, _totalSupplySnapshots);
                                          return snapshotted ? value : totalSupply();
                                        }
                                        // Update balance and/or total supply snapshots before the values are modified. This is implemented
                                        // in the _beforeTokenTransfer hook, which is executed for _mint, _burn, and _transfer operations.
                                        function _beforeTokenTransfer(
                                          address from,
                                          address to,
                                          uint256 amount
                                        ) internal virtual override {
                                          super._beforeTokenTransfer(from, to, amount);
                                          if (from == address(0)) {
                                            // mint
                                            _updateAccountSnapshot(to);
                                            _updateTotalSupplySnapshot();
                                          } else if (to == address(0)) {
                                            // burn
                                            _updateAccountSnapshot(from);
                                            _updateTotalSupplySnapshot();
                                          } else {
                                            // transfer
                                            _updateAccountSnapshot(from);
                                            _updateAccountSnapshot(to);
                                          }
                                        }
                                        function _valueAt(uint256 snapshotId, Snapshots storage snapshots)
                                          private
                                          view
                                          returns (bool, uint256)
                                        {
                                          require(snapshotId > 0, "ERC20Snapshot: id is 0");
                                          // solhint-disable-next-line max-line-length
                                          require(
                                            snapshotId <= _currentSnapshotId.current(),
                                            "ERC20Snapshot: nonexistent id"
                                          );
                                          // When a valid snapshot is queried, there are three possibilities:
                                          //  a) The queried value was not modified after the snapshot was taken. Therefore, a snapshot entry was never
                                          //  created for this id, and all stored snapshot ids are smaller than the requested one. The value that corresponds
                                          //  to this id is the current one.
                                          //  b) The queried value was modified after the snapshot was taken. Therefore, there will be an entry with the
                                          //  requested id, and its value is the one to return.
                                          //  c) More snapshots were created after the requested one, and the queried value was later modified. There will be
                                          //  no entry for the requested id: the value that corresponds to it is that of the smallest snapshot id that is
                                          //  larger than the requested one.
                                          //
                                          // In summary, we need to find an element in an array, returning the index of the smallest value that is larger if
                                          // it is not found, unless said value doesn't exist (e.g. when all values are smaller). Arrays.findUpperBound does
                                          // exactly this.
                                          uint256 index = snapshots.ids.findUpperBound(snapshotId);
                                          if (index == snapshots.ids.length) {
                                            return (false, 0);
                                          } else {
                                            return (true, snapshots.values[index]);
                                          }
                                        }
                                        function _updateAccountSnapshot(address account) internal {
                                          _updateSnapshot(_accountBalanceSnapshots[account], balanceOf(account));
                                        }
                                        function _updateTotalSupplySnapshot() internal {
                                          _updateSnapshot(_totalSupplySnapshots, totalSupply());
                                        }
                                        function _updateSnapshot(Snapshots storage snapshots, uint256 currentValue)
                                          private
                                        {
                                          uint256 currentId = _currentSnapshotId.current();
                                          if (_lastSnapshotId(snapshots.ids) < currentId) {
                                            snapshots.ids.push(currentId);
                                            snapshots.values.push(currentValue);
                                          }
                                        }
                                        function _lastSnapshotId(uint256[] storage ids)
                                          private
                                          view
                                          returns (uint256)
                                        {
                                          if (ids.length == 0) {
                                            return 0;
                                          } else {
                                            return ids[ids.length - 1];
                                          }
                                        }
                                        uint256[46] private __gap;
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      import "./ERC20Upgradeable.sol";
                                      import "@openzeppelin/contracts-upgradeable/security/PausableUpgradeable.sol";
                                      import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";
                                      /**
                                       * @dev ERC20 token with pausable token transfers, minting and burning.
                                       *
                                       * Useful for scenarios such as preventing trades until the end of an evaluation
                                       * period, or having an emergency switch for freezing all token transfers in the
                                       * event of a large bug.
                                       */
                                      abstract contract ERC20PausableUpgradeable is
                                        Initializable,
                                        ERC20Upgradeable,
                                        PausableUpgradeable
                                      {
                                        function __ERC20Pausable_init() internal initializer {
                                          __Context_init_unchained();
                                          __Pausable_init_unchained();
                                          __ERC20Pausable_init_unchained();
                                        }
                                        function __ERC20Pausable_init_unchained() internal initializer {}
                                        /**
                                         * @dev See {ERC20-_beforeTokenTransfer}.
                                         *
                                         * Requirements:
                                         *
                                         * - the contract must not be paused.
                                         */
                                        function _beforeTokenTransfer(
                                          address from,
                                          address to,
                                          uint256 amount
                                        ) internal virtual override {
                                          super._beforeTokenTransfer(from, to, amount);
                                          require(!paused(), "ERC20Pausable: token transfer while paused");
                                        }
                                        uint256[50] private __gap;
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      import "../utils/ContextUpgradeable.sol";
                                      import "../proxy/utils/Initializable.sol";
                                      /**
                                       * @dev Contract module which provides a basic access control mechanism, where
                                       * there is an account (an owner) that can be granted exclusive access to
                                       * specific functions.
                                       *
                                       * By default, the owner account will be the one that deploys the contract. This
                                       * can later be changed with {transferOwnership}.
                                       *
                                       * This module is used through inheritance. It will make available the modifier
                                       * `onlyOwner`, which can be applied to your functions to restrict their use to
                                       * the owner.
                                       */
                                      abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
                                          address private _owner;
                                          event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
                                          /**
                                           * @dev Initializes the contract setting the deployer as the initial owner.
                                           */
                                          function __Ownable_init() internal initializer {
                                              __Context_init_unchained();
                                              __Ownable_init_unchained();
                                          }
                                          function __Ownable_init_unchained() internal initializer {
                                              address msgSender = _msgSender();
                                              _owner = msgSender;
                                              emit OwnershipTransferred(address(0), msgSender);
                                          }
                                          /**
                                           * @dev Returns the address of the current owner.
                                           */
                                          function owner() public view virtual returns (address) {
                                              return _owner;
                                          }
                                          /**
                                           * @dev Throws if called by any account other than the owner.
                                           */
                                          modifier onlyOwner() {
                                              require(owner() == _msgSender(), "Ownable: caller is not the owner");
                                              _;
                                          }
                                          /**
                                           * @dev Leaves the contract without owner. It will not be possible to call
                                           * `onlyOwner` functions anymore. Can only be called by the current owner.
                                           *
                                           * NOTE: Renouncing ownership will leave the contract without an owner,
                                           * thereby removing any functionality that is only available to the owner.
                                           */
                                          function renounceOwnership() public virtual onlyOwner {
                                              emit OwnershipTransferred(_owner, address(0));
                                              _owner = address(0);
                                          }
                                          /**
                                           * @dev Transfers ownership of the contract to a new account (`newOwner`).
                                           * Can only be called by the current owner.
                                           */
                                          function transferOwnership(address newOwner) public virtual onlyOwner {
                                              require(newOwner != address(0), "Ownable: new owner is the zero address");
                                              emit OwnershipTransferred(_owner, newOwner);
                                              _owner = newOwner;
                                          }
                                          uint256[49] private __gap;
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      /**
                                       * @dev Interface of the ERC20 standard as defined in the EIP.
                                       */
                                      interface IERC20Upgradeable {
                                          /**
                                           * @dev Returns the amount of tokens in existence.
                                           */
                                          function totalSupply() external view returns (uint256);
                                          /**
                                           * @dev Returns the amount of tokens owned by `account`.
                                           */
                                          function balanceOf(address account) external view returns (uint256);
                                          /**
                                           * @dev Moves `amount` tokens from the caller's account to `recipient`.
                                           *
                                           * Returns a boolean value indicating whether the operation succeeded.
                                           *
                                           * Emits a {Transfer} event.
                                           */
                                          function transfer(address recipient, uint256 amount) external returns (bool);
                                          /**
                                           * @dev Returns the remaining number of tokens that `spender` will be
                                           * allowed to spend on behalf of `owner` through {transferFrom}. This is
                                           * zero by default.
                                           *
                                           * This value changes when {approve} or {transferFrom} are called.
                                           */
                                          function allowance(address owner, address spender) external view returns (uint256);
                                          /**
                                           * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
                                           *
                                           * Returns a boolean value indicating whether the operation succeeded.
                                           *
                                           * IMPORTANT: Beware that changing an allowance with this method brings the risk
                                           * that someone may use both the old and the new allowance by unfortunate
                                           * transaction ordering. One possible solution to mitigate this race
                                           * condition is to first reduce the spender's allowance to 0 and set the
                                           * desired value afterwards:
                                           * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                                           *
                                           * Emits an {Approval} event.
                                           */
                                          function approve(address spender, uint256 amount) external returns (bool);
                                          /**
                                           * @dev Moves `amount` tokens from `sender` to `recipient` using the
                                           * allowance mechanism. `amount` is then deducted from the caller's
                                           * allowance.
                                           *
                                           * Returns a boolean value indicating whether the operation succeeded.
                                           *
                                           * Emits a {Transfer} event.
                                           */
                                          function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
                                          /**
                                           * @dev Emitted when `value` tokens are moved from one account (`from`) to
                                           * another (`to`).
                                           *
                                           * Note that `value` may be zero.
                                           */
                                          event Transfer(address indexed from, address indexed to, uint256 value);
                                          /**
                                           * @dev Emitted when the allowance of a `spender` for an `owner` is set by
                                           * a call to {approve}. `value` is the new allowance.
                                           */
                                          event Approval(address indexed owner, address indexed spender, uint256 value);
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      import "../proxy/utils/Initializable.sol";
                                      /*
                                       * @dev Provides information about the current execution context, including the
                                       * sender of the transaction and its data. While these are generally available
                                       * via msg.sender and msg.data, they should not be accessed in such a direct
                                       * manner, since when dealing with meta-transactions the account sending and
                                       * paying for execution may not be the actual sender (as far as an application
                                       * is concerned).
                                       *
                                       * This contract is only required for intermediate, library-like contracts.
                                       */
                                      abstract contract ContextUpgradeable is Initializable {
                                          function __Context_init() internal initializer {
                                              __Context_init_unchained();
                                          }
                                          function __Context_init_unchained() internal initializer {
                                          }
                                          function _msgSender() internal view virtual returns (address) {
                                              return msg.sender;
                                          }
                                          function _msgData() internal view virtual returns (bytes calldata) {
                                              this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
                                              return msg.data;
                                          }
                                          uint256[50] private __gap;
                                      }
                                      // SPDX-License-Identifier: MIT
                                      // solhint-disable-next-line compiler-version
                                      pragma solidity ^0.8.0;
                                      import "../../utils/AddressUpgradeable.sol";
                                      /**
                                       * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
                                       * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
                                       * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
                                       * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
                                       *
                                       * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
                                       * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
                                       *
                                       * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
                                       * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
                                       */
                                      abstract contract Initializable {
                                          /**
                                           * @dev Indicates that the contract has been initialized.
                                           */
                                          bool private _initialized;
                                          /**
                                           * @dev Indicates that the contract is in the process of being initialized.
                                           */
                                          bool private _initializing;
                                          /**
                                           * @dev Modifier to protect an initializer function from being invoked twice.
                                           */
                                          modifier initializer() {
                                              require(_initializing || !_initialized, "Initializable: contract is already initialized");
                                              bool isTopLevelCall = !_initializing;
                                              if (isTopLevelCall) {
                                                  _initializing = true;
                                                  _initialized = true;
                                              }
                                              _;
                                              if (isTopLevelCall) {
                                                  _initializing = false;
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      /**
                                       * @dev Collection of functions related to the address type
                                       */
                                      library AddressUpgradeable {
                                          /**
                                           * @dev Returns true if `account` is a contract.
                                           *
                                           * [IMPORTANT]
                                           * ====
                                           * It is unsafe to assume that an address for which this function returns
                                           * false is an externally-owned account (EOA) and not a contract.
                                           *
                                           * Among others, `isContract` will return false for the following
                                           * types of addresses:
                                           *
                                           *  - an externally-owned account
                                           *  - a contract in construction
                                           *  - an address where a contract will be created
                                           *  - an address where a contract lived, but was destroyed
                                           * ====
                                           */
                                          function isContract(address account) internal view returns (bool) {
                                              // This method relies on extcodesize, which returns 0 for contracts in
                                              // construction, since the code is only stored at the end of the
                                              // constructor execution.
                                              uint256 size;
                                              // solhint-disable-next-line no-inline-assembly
                                              assembly { size := extcodesize(account) }
                                              return size > 0;
                                          }
                                          /**
                                           * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
                                           * `recipient`, forwarding all available gas and reverting on errors.
                                           *
                                           * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
                                           * of certain opcodes, possibly making contracts go over the 2300 gas limit
                                           * imposed by `transfer`, making them unable to receive funds via
                                           * `transfer`. {sendValue} removes this limitation.
                                           *
                                           * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
                                           *
                                           * IMPORTANT: because control is transferred to `recipient`, care must be
                                           * taken to not create reentrancy vulnerabilities. Consider using
                                           * {ReentrancyGuard} or the
                                           * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
                                           */
                                          function sendValue(address payable recipient, uint256 amount) internal {
                                              require(address(this).balance >= amount, "Address: insufficient balance");
                                              // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
                                              (bool success, ) = recipient.call{ value: amount }("");
                                              require(success, "Address: unable to send value, recipient may have reverted");
                                          }
                                          /**
                                           * @dev Performs a Solidity function call using a low level `call`. A
                                           * plain`call` is an unsafe replacement for a function call: use this
                                           * function instead.
                                           *
                                           * If `target` reverts with a revert reason, it is bubbled up by this
                                           * function (like regular Solidity function calls).
                                           *
                                           * Returns the raw returned data. To convert to the expected return value,
                                           * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
                                           *
                                           * Requirements:
                                           *
                                           * - `target` must be a contract.
                                           * - calling `target` with `data` must not revert.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCall(address target, bytes memory data) internal returns (bytes memory) {
                                            return functionCall(target, data, "Address: low-level call failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
                                           * `errorMessage` as a fallback revert reason when `target` reverts.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
                                              return functionCallWithValue(target, data, 0, errorMessage);
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                                           * but also transferring `value` wei to `target`.
                                           *
                                           * Requirements:
                                           *
                                           * - the calling contract must have an ETH balance of at least `value`.
                                           * - the called Solidity function must be `payable`.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
                                              return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
                                           * with `errorMessage` as a fallback revert reason when `target` reverts.
                                           *
                                           * _Available since v3.1._
                                           */
                                          function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
                                              require(address(this).balance >= value, "Address: insufficient balance for call");
                                              require(isContract(target), "Address: call to non-contract");
                                              // solhint-disable-next-line avoid-low-level-calls
                                              (bool success, bytes memory returndata) = target.call{ value: value }(data);
                                              return _verifyCallResult(success, returndata, errorMessage);
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
                                           * but performing a static call.
                                           *
                                           * _Available since v3.3._
                                           */
                                          function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
                                              return functionStaticCall(target, data, "Address: low-level static call failed");
                                          }
                                          /**
                                           * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
                                           * but performing a static call.
                                           *
                                           * _Available since v3.3._
                                           */
                                          function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
                                              require(isContract(target), "Address: static call to non-contract");
                                              // solhint-disable-next-line avoid-low-level-calls
                                              (bool success, bytes memory returndata) = target.staticcall(data);
                                              return _verifyCallResult(success, returndata, errorMessage);
                                          }
                                          function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
                                              if (success) {
                                                  return returndata;
                                              } else {
                                                  // Look for revert reason and bubble it up if present
                                                  if (returndata.length > 0) {
                                                      // The easiest way to bubble the revert reason is using memory via assembly
                                                      // solhint-disable-next-line no-inline-assembly
                                                      assembly {
                                                          let returndata_size := mload(returndata)
                                                          revert(add(32, returndata), returndata_size)
                                                      }
                                                  } else {
                                                      revert(errorMessage);
                                                  }
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      import "./math/MathUpgradeable.sol";
                                      /**
                                       * @dev Collection of functions related to array types.
                                       */
                                      library ArraysUpgradeable {
                                         /**
                                           * @dev Searches a sorted `array` and returns the first index that contains
                                           * a value greater or equal to `element`. If no such index exists (i.e. all
                                           * values in the array are strictly less than `element`), the array length is
                                           * returned. Time complexity O(log n).
                                           *
                                           * `array` is expected to be sorted in ascending order, and to contain no
                                           * repeated elements.
                                           */
                                          function findUpperBound(uint256[] storage array, uint256 element) internal view returns (uint256) {
                                              if (array.length == 0) {
                                                  return 0;
                                              }
                                              uint256 low = 0;
                                              uint256 high = array.length;
                                              while (low < high) {
                                                  uint256 mid = MathUpgradeable.average(low, high);
                                                  // Note that mid will always be strictly less than high (i.e. it will be a valid array index)
                                                  // because Math.average rounds down (it does integer division with truncation).
                                                  if (array[mid] > element) {
                                                      high = mid;
                                                  } else {
                                                      low = mid + 1;
                                                  }
                                              }
                                              // At this point `low` is the exclusive upper bound. We will return the inclusive upper bound.
                                              if (low > 0 && array[low - 1] == element) {
                                                  return low - 1;
                                              } else {
                                                  return low;
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      /**
                                       * @title Counters
                                       * @author Matt Condon (@shrugs)
                                       * @dev Provides counters that can only be incremented or decremented by one. This can be used e.g. to track the number
                                       * of elements in a mapping, issuing ERC721 ids, or counting request ids.
                                       *
                                       * Include with `using Counters for Counters.Counter;`
                                       */
                                      library CountersUpgradeable {
                                          struct Counter {
                                              // This variable should never be directly accessed by users of the library: interactions must be restricted to
                                              // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
                                              // this feature: see https://github.com/ethereum/solidity/issues/4637
                                              uint256 _value; // default: 0
                                          }
                                          function current(Counter storage counter) internal view returns (uint256) {
                                              return counter._value;
                                          }
                                          function increment(Counter storage counter) internal {
                                              unchecked {
                                                  counter._value += 1;
                                              }
                                          }
                                          function decrement(Counter storage counter) internal {
                                              uint256 value = counter._value;
                                              require(value > 0, "Counter: decrement overflow");
                                              unchecked {
                                                  counter._value = value - 1;
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      /**
                                       * @dev Standard math utilities missing in the Solidity language.
                                       */
                                      library MathUpgradeable {
                                          /**
                                           * @dev Returns the largest of two numbers.
                                           */
                                          function max(uint256 a, uint256 b) internal pure returns (uint256) {
                                              return a >= b ? a : b;
                                          }
                                          /**
                                           * @dev Returns the smallest of two numbers.
                                           */
                                          function min(uint256 a, uint256 b) internal pure returns (uint256) {
                                              return a < b ? a : b;
                                          }
                                          /**
                                           * @dev Returns the average of two numbers. The result is rounded towards
                                           * zero.
                                           */
                                          function average(uint256 a, uint256 b) internal pure returns (uint256) {
                                              // (a + b) / 2 can overflow, so we distribute
                                              return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
                                          }
                                      }
                                      // SPDX-License-Identifier: MIT
                                      pragma solidity ^0.8.0;
                                      import "../utils/ContextUpgradeable.sol";
                                      import "../proxy/utils/Initializable.sol";
                                      /**
                                       * @dev Contract module which allows children to implement an emergency stop
                                       * mechanism that can be triggered by an authorized account.
                                       *
                                       * This module is used through inheritance. It will make available the
                                       * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
                                       * the functions of your contract. Note that they will not be pausable by
                                       * simply including this module, only once the modifiers are put in place.
                                       */
                                      abstract contract PausableUpgradeable is Initializable, ContextUpgradeable {
                                          /**
                                           * @dev Emitted when the pause is triggered by `account`.
                                           */
                                          event Paused(address account);
                                          /**
                                           * @dev Emitted when the pause is lifted by `account`.
                                           */
                                          event Unpaused(address account);
                                          bool private _paused;
                                          /**
                                           * @dev Initializes the contract in unpaused state.
                                           */
                                          function __Pausable_init() internal initializer {
                                              __Context_init_unchained();
                                              __Pausable_init_unchained();
                                          }
                                          function __Pausable_init_unchained() internal initializer {
                                              _paused = false;
                                          }
                                          /**
                                           * @dev Returns true if the contract is paused, and false otherwise.
                                           */
                                          function paused() public view virtual returns (bool) {
                                              return _paused;
                                          }
                                          /**
                                           * @dev Modifier to make a function callable only when the contract is not paused.
                                           *
                                           * Requirements:
                                           *
                                           * - The contract must not be paused.
                                           */
                                          modifier whenNotPaused() {
                                              require(!paused(), "Pausable: paused");
                                              _;
                                          }
                                          /**
                                           * @dev Modifier to make a function callable only when the contract is paused.
                                           *
                                           * Requirements:
                                           *
                                           * - The contract must be paused.
                                           */
                                          modifier whenPaused() {
                                              require(paused(), "Pausable: not paused");
                                              _;
                                          }
                                          /**
                                           * @dev Triggers stopped state.
                                           *
                                           * Requirements:
                                           *
                                           * - The contract must not be paused.
                                           */
                                          function _pause() internal virtual whenNotPaused {
                                              _paused = true;
                                              emit Paused(_msgSender());
                                          }
                                          /**
                                           * @dev Returns to normal state.
                                           *
                                           * Requirements:
                                           *
                                           * - The contract must be paused.
                                           */
                                          function _unpause() internal virtual whenPaused {
                                              _paused = false;
                                              emit Unpaused(_msgSender());
                                          }
                                          uint256[49] private __gap;
                                      }
                                      

                                      File 9 of 11: MultiplexFeature
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "@0x/contracts-erc20/src/IEtherToken.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../../external/ILiquidityProviderSandbox.sol";
                                      import "../../fixins/FixinCommon.sol";
                                      import "../../fixins/FixinEIP712.sol";
                                      import "../../migrations/LibMigrate.sol";
                                      import "../interfaces/IFeature.sol";
                                      import "../interfaces/IMultiplexFeature.sol";
                                      import "./MultiplexLiquidityProvider.sol";
                                      import "./MultiplexOtc.sol";
                                      import "./MultiplexRfq.sol";
                                      import "./MultiplexTransformERC20.sol";
                                      import "./MultiplexUniswapV2.sol";
                                      import "./MultiplexUniswapV3.sol";
                                      /// @dev This feature enables efficient batch and multi-hop trades
                                      ///      using different liquidity sources.
                                      contract MultiplexFeature is
                                          IFeature,
                                          IMultiplexFeature,
                                          FixinCommon,
                                          MultiplexLiquidityProvider,
                                          MultiplexOtc,
                                          MultiplexRfq,
                                          MultiplexTransformERC20,
                                          MultiplexUniswapV2,
                                          MultiplexUniswapV3
                                      {
                                          /// @dev Name of this feature.
                                          string public constant override FEATURE_NAME = "MultiplexFeature";
                                          /// @dev Version of this feature.
                                          uint256 public immutable override FEATURE_VERSION = _encodeVersion(2, 0, 0);
                                          /// @dev The highest bit of a uint256 value.
                                          uint256 private constant HIGH_BIT = 2 ** 255;
                                          /// @dev Mask of the lower 255 bits of a uint256 value.
                                          uint256 private constant LOWER_255_BITS = HIGH_BIT - 1;
                                          /// @dev The WETH token contract.
                                          IEtherToken private immutable WETH;
                                          constructor(
                                              address zeroExAddress,
                                              IEtherToken weth,
                                              ILiquidityProviderSandbox sandbox,
                                              address uniswapFactory,
                                              address sushiswapFactory,
                                              bytes32 uniswapPairInitCodeHash,
                                              bytes32 sushiswapPairInitCodeHash
                                          )
                                              public
                                              FixinEIP712(zeroExAddress)
                                              MultiplexLiquidityProvider(sandbox)
                                              MultiplexUniswapV2(uniswapFactory, sushiswapFactory, uniswapPairInitCodeHash, sushiswapPairInitCodeHash)
                                          {
                                              WETH = weth;
                                          }
                                          /// @dev Initialize and register this feature.
                                          ///      Should be delegatecalled by `Migrate.migrate()`.
                                          /// @return success `LibMigrate.SUCCESS` on success.
                                          function migrate() external returns (bytes4 success) {
                                              _registerFeatureFunction(this.multiplexBatchSellEthForToken.selector);
                                              _registerFeatureFunction(this.multiplexBatchSellTokenForEth.selector);
                                              _registerFeatureFunction(this.multiplexBatchSellTokenForToken.selector);
                                              _registerFeatureFunction(this._multiplexBatchSell.selector);
                                              _registerFeatureFunction(this.multiplexMultiHopSellEthForToken.selector);
                                              _registerFeatureFunction(this.multiplexMultiHopSellTokenForEth.selector);
                                              _registerFeatureFunction(this.multiplexMultiHopSellTokenForToken.selector);
                                              _registerFeatureFunction(this._multiplexMultiHopSell.selector);
                                              return LibMigrate.MIGRATE_SUCCESS;
                                          }
                                          /// @dev Sells attached ETH for `outputToken` using the provided
                                          ///      calls.
                                          /// @param outputToken The token to buy.
                                          /// @param calls The calls to use to sell the attached ETH.
                                          /// @param minBuyAmount The minimum amount of `outputToken` that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of `outputToken` bought.
                                          function multiplexBatchSellEthForToken(
                                              IERC20Token outputToken,
                                              BatchSellSubcall[] memory calls,
                                              uint256 minBuyAmount
                                          ) public payable override returns (uint256 boughtAmount) {
                                              // Wrap ETH.
                                              WETH.deposit{value: msg.value}();
                                              // WETH is now held by this contract,
                                              // so `useSelfBalance` is true.
                                              return
                                                  _multiplexBatchSellPrivate(
                                                      BatchSellParams({
                                                          inputToken: WETH,
                                                          outputToken: outputToken,
                                                          sellAmount: msg.value,
                                                          calls: calls,
                                                          useSelfBalance: true,
                                                          recipient: msg.sender,
                                                          payer: msg.sender
                                                      }),
                                                      minBuyAmount
                                                  );
                                          }
                                          /// @dev Sells `sellAmount` of the given `inputToken` for ETH
                                          ///      using the provided calls.
                                          /// @param inputToken The token to sell.
                                          /// @param calls The calls to use to sell the input tokens.
                                          /// @param sellAmount The amount of `inputToken` to sell.
                                          /// @param minBuyAmount The minimum amount of ETH that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of ETH bought.
                                          function multiplexBatchSellTokenForEth(
                                              IERC20Token inputToken,
                                              BatchSellSubcall[] memory calls,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount
                                          ) public override returns (uint256 boughtAmount) {
                                              // The outputToken is implicitly WETH. The `recipient`
                                              // of the WETH is set to  this contract, since we
                                              // must unwrap the WETH and transfer the resulting ETH.
                                              boughtAmount = _multiplexBatchSellPrivate(
                                                  BatchSellParams({
                                                      inputToken: inputToken,
                                                      outputToken: WETH,
                                                      sellAmount: sellAmount,
                                                      calls: calls,
                                                      useSelfBalance: false,
                                                      recipient: address(this),
                                                      payer: msg.sender
                                                  }),
                                                  minBuyAmount
                                              );
                                              // Unwrap WETH.
                                              WETH.withdraw(boughtAmount);
                                              // Transfer ETH to `msg.sender`.
                                              _transferEth(msg.sender, boughtAmount);
                                          }
                                          /// @dev Sells `sellAmount` of the given `inputToken` for
                                          ///      `outputToken` using the provided calls.
                                          /// @param inputToken The token to sell.
                                          /// @param outputToken The token to buy.
                                          /// @param calls The calls to use to sell the input tokens.
                                          /// @param sellAmount The amount of `inputToken` to sell.
                                          /// @param minBuyAmount The minimum amount of `outputToken`
                                          ///        that must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of `outputToken` bought.
                                          function multiplexBatchSellTokenForToken(
                                              IERC20Token inputToken,
                                              IERC20Token outputToken,
                                              BatchSellSubcall[] memory calls,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount
                                          ) public override returns (uint256 boughtAmount) {
                                              return
                                                  _multiplexBatchSellPrivate(
                                                      BatchSellParams({
                                                          inputToken: inputToken,
                                                          outputToken: outputToken,
                                                          sellAmount: sellAmount,
                                                          calls: calls,
                                                          useSelfBalance: false,
                                                          recipient: msg.sender,
                                                          payer: msg.sender
                                                      }),
                                                      minBuyAmount
                                                  );
                                          }
                                          /// @dev Executes a batch sell and checks that at least
                                          ///      `minBuyAmount` of `outputToken` was bought. Internal variant.
                                          /// @param params Batch sell parameters.
                                          /// @param minBuyAmount The minimum amount of `outputToken` that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of `outputToken` bought.
                                          function _multiplexBatchSell(
                                              BatchSellParams memory params,
                                              uint256 minBuyAmount
                                          ) public override onlySelf returns (uint256 boughtAmount) {
                                              return _multiplexBatchSellPrivate(params, minBuyAmount);
                                          }
                                          /// @dev Executes a batch sell and checks that at least
                                          ///      `minBuyAmount` of `outputToken` was bought.
                                          /// @param params Batch sell parameters.
                                          /// @param minBuyAmount The minimum amount of `outputToken` that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of `outputToken` bought.
                                          function _multiplexBatchSellPrivate(
                                              BatchSellParams memory params,
                                              uint256 minBuyAmount
                                          ) private returns (uint256 boughtAmount) {
                                              // Cache the recipient's initial balance of the output token.
                                              uint256 balanceBefore = params.outputToken.balanceOf(params.recipient);
                                              // Execute the batch sell.
                                              BatchSellState memory state = _executeBatchSell(params);
                                              // Compute the change in balance of the output token.
                                              uint256 balanceDelta = params.outputToken.balanceOf(params.recipient).safeSub(balanceBefore);
                                              // Use the minimum of the balanceDelta and the returned bought
                                              // amount in case of weird tokens and whatnot.
                                              boughtAmount = LibSafeMathV06.min256(balanceDelta, state.boughtAmount);
                                              // Enforce `minBuyAmount`.
                                              require(boughtAmount >= minBuyAmount, "MultiplexFeature::_multiplexBatchSell/UNDERBOUGHT");
                                          }
                                          /// @dev Sells attached ETH via the given sequence of tokens
                                          ///      and calls. `tokens[0]` must be WETH.
                                          ///      The last token in `tokens` is the output token that
                                          ///      will ultimately be sent to `msg.sender`
                                          /// @param tokens The sequence of tokens to use for the sell,
                                          ///        i.e. `tokens[i]` will be sold for `tokens[i+1]` via
                                          ///        `calls[i]`.
                                          /// @param calls The sequence of calls to use for the sell.
                                          /// @param minBuyAmount The minimum amount of output tokens that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of output tokens bought.
                                          function multiplexMultiHopSellEthForToken(
                                              address[] memory tokens,
                                              MultiHopSellSubcall[] memory calls,
                                              uint256 minBuyAmount
                                          ) public payable override returns (uint256 boughtAmount) {
                                              // First token must be WETH.
                                              require(tokens[0] == address(WETH), "MultiplexFeature::multiplexMultiHopSellEthForToken/NOT_WETH");
                                              // Wrap ETH.
                                              WETH.deposit{value: msg.value}();
                                              // WETH is now held by this contract,
                                              // so `useSelfBalance` is true.
                                              return
                                                  _multiplexMultiHopSellPrivate(
                                                      MultiHopSellParams({
                                                          tokens: tokens,
                                                          sellAmount: msg.value,
                                                          calls: calls,
                                                          useSelfBalance: true,
                                                          recipient: msg.sender,
                                                          payer: msg.sender
                                                      }),
                                                      minBuyAmount
                                                  );
                                          }
                                          /// @dev Sells `sellAmount` of the input token (`tokens[0]`)
                                          ///      for ETH via the given sequence of tokens and calls.
                                          ///      The last token in `tokens` must be WETH.
                                          /// @param tokens The sequence of tokens to use for the sell,
                                          ///        i.e. `tokens[i]` will be sold for `tokens[i+1]` via
                                          ///        `calls[i]`.
                                          /// @param calls The sequence of calls to use for the sell.
                                          /// @param sellAmount The amount of `inputToken` to sell.
                                          /// @param minBuyAmount The minimum amount of ETH that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of ETH bought.
                                          function multiplexMultiHopSellTokenForEth(
                                              address[] memory tokens,
                                              MultiHopSellSubcall[] memory calls,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount
                                          ) public override returns (uint256 boughtAmount) {
                                              // Last token must be WETH.
                                              require(
                                                  tokens[tokens.length - 1] == address(WETH),
                                                  "MultiplexFeature::multiplexMultiHopSellTokenForEth/NOT_WETH"
                                              );
                                              // The `recipient of the WETH is set to  this contract, since
                                              // we must unwrap the WETH and transfer the resulting ETH.
                                              boughtAmount = _multiplexMultiHopSellPrivate(
                                                  MultiHopSellParams({
                                                      tokens: tokens,
                                                      sellAmount: sellAmount,
                                                      calls: calls,
                                                      useSelfBalance: false,
                                                      recipient: address(this),
                                                      payer: msg.sender
                                                  }),
                                                  minBuyAmount
                                              );
                                              // Unwrap WETH.
                                              WETH.withdraw(boughtAmount);
                                              // Transfer ETH to `msg.sender`.
                                              _transferEth(msg.sender, boughtAmount);
                                          }
                                          /// @dev Sells `sellAmount` of the input token (`tokens[0]`)
                                          ///      via the given sequence of tokens and calls.
                                          ///      The last token in `tokens` is the output token that
                                          ///      will ultimately be sent to `msg.sender`
                                          /// @param tokens The sequence of tokens to use for the sell,
                                          ///        i.e. `tokens[i]` will be sold for `tokens[i+1]` via
                                          ///        `calls[i]`.
                                          /// @param calls The sequence of calls to use for the sell.
                                          /// @param sellAmount The amount of `inputToken` to sell.
                                          /// @param minBuyAmount The minimum amount of output tokens that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of output tokens bought.
                                          function multiplexMultiHopSellTokenForToken(
                                              address[] memory tokens,
                                              MultiHopSellSubcall[] memory calls,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount
                                          ) public override returns (uint256 boughtAmount) {
                                              return
                                                  _multiplexMultiHopSellPrivate(
                                                      MultiHopSellParams({
                                                          tokens: tokens,
                                                          sellAmount: sellAmount,
                                                          calls: calls,
                                                          useSelfBalance: false,
                                                          recipient: msg.sender,
                                                          payer: msg.sender
                                                      }),
                                                      minBuyAmount
                                                  );
                                          }
                                          /// @dev Executes a multi-hop sell. Internal variant.
                                          /// @param params Multi-hop sell parameters.
                                          /// @param minBuyAmount The minimum amount of output tokens that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of output tokens bought.
                                          function _multiplexMultiHopSell(
                                              MultiHopSellParams memory params,
                                              uint256 minBuyAmount
                                          ) public override onlySelf returns (uint256 boughtAmount) {
                                              return _multiplexMultiHopSellPrivate(params, minBuyAmount);
                                          }
                                          /// @dev Executes a multi-hop sell and checks that at least
                                          ///      `minBuyAmount` of output tokens were bought.
                                          /// @param params Multi-hop sell parameters.
                                          /// @param minBuyAmount The minimum amount of output tokens that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of output tokens bought.
                                          function _multiplexMultiHopSellPrivate(
                                              MultiHopSellParams memory params,
                                              uint256 minBuyAmount
                                          ) private returns (uint256 boughtAmount) {
                                              // There should be one call/hop between every two tokens
                                              // in the path.
                                              // tokens[0]b\u0000\u0013b\u0000\u0013calls[0]b\u0000\u0013b\u0000\u0013>tokens[1]b\u0000\u0013b\u0000\u0013...b\u0000\u0013b\u0000\u0013calls[n-1]b\u0000\u0013b\u0000\u0013>tokens[n]
                                              require(
                                                  params.tokens.length == params.calls.length + 1,
                                                  "MultiplexFeature::_multiplexMultiHopSell/MISMATCHED_ARRAY_LENGTHS"
                                              );
                                              // The output token is the last token in the path.
                                              IERC20Token outputToken = IERC20Token(params.tokens[params.tokens.length - 1]);
                                              // Cache the recipient's balance of the output token.
                                              uint256 balanceBefore = outputToken.balanceOf(params.recipient);
                                              // Execute the multi-hop sell.
                                              MultiHopSellState memory state = _executeMultiHopSell(params);
                                              // Compute the change in balance of the output token.
                                              uint256 balanceDelta = outputToken.balanceOf(params.recipient).safeSub(balanceBefore);
                                              // Use the minimum of the balanceDelta and the returned bought
                                              // amount in case of weird tokens and whatnot.
                                              boughtAmount = LibSafeMathV06.min256(balanceDelta, state.outputTokenAmount);
                                              // Enforce `minBuyAmount`.
                                              require(boughtAmount >= minBuyAmount, "MultiplexFeature::_multiplexMultiHopSell/UNDERBOUGHT");
                                          }
                                          /// @dev Iterates through the constituent calls of a batch
                                          ///      sell and executes each one, until the full amount
                                          //       has been sold.
                                          /// @param params Batch sell parameters.
                                          /// @return state A struct containing the amounts of `inputToken`
                                          ///         sold and `outputToken` bought.
                                          function _executeBatchSell(BatchSellParams memory params) private returns (BatchSellState memory state) {
                                              // Iterate through the calls and execute each one
                                              // until the full amount has been sold.
                                              for (uint256 i = 0; i != params.calls.length; i++) {
                                                  // Check if we've hit our target.
                                                  if (state.soldAmount >= params.sellAmount) {
                                                      break;
                                                  }
                                                  BatchSellSubcall memory subcall = params.calls[i];
                                                  // Compute the input token amount.
                                                  uint256 inputTokenAmount = _normalizeSellAmount(subcall.sellAmount, params.sellAmount, state.soldAmount);
                                                  if (subcall.id == MultiplexSubcall.RFQ) {
                                                      _batchSellRfqOrder(state, params, subcall.data, inputTokenAmount);
                                                  } else if (subcall.id == MultiplexSubcall.OTC) {
                                                      _batchSellOtcOrder(state, params, subcall.data, inputTokenAmount);
                                                  } else if (subcall.id == MultiplexSubcall.UniswapV2) {
                                                      _batchSellUniswapV2(state, params, subcall.data, inputTokenAmount);
                                                  } else if (subcall.id == MultiplexSubcall.UniswapV3) {
                                                      _batchSellUniswapV3(state, params, subcall.data, inputTokenAmount);
                                                  } else if (subcall.id == MultiplexSubcall.LiquidityProvider) {
                                                      _batchSellLiquidityProvider(state, params, subcall.data, inputTokenAmount);
                                                  } else if (subcall.id == MultiplexSubcall.TransformERC20) {
                                                      _batchSellTransformERC20(state, params, subcall.data, inputTokenAmount);
                                                  } else if (subcall.id == MultiplexSubcall.MultiHopSell) {
                                                      _nestedMultiHopSell(state, params, subcall.data, inputTokenAmount);
                                                  } else {
                                                      revert("MultiplexFeature::_executeBatchSell/INVALID_SUBCALL");
                                                  }
                                              }
                                              require(state.soldAmount == params.sellAmount, "MultiplexFeature::_executeBatchSell/INCORRECT_AMOUNT_SOLD");
                                          }
                                          // This function executes a sequence of fills "hopping" through the
                                          // path of tokens given by `params.tokens`.
                                          function _executeMultiHopSell(MultiHopSellParams memory params) private returns (MultiHopSellState memory state) {
                                              // This variable is used for the input and output amounts of
                                              // each hop. After the final hop, this will contain the output
                                              // amount of the multi-hop fill.
                                              state.outputTokenAmount = params.sellAmount;
                                              // The first call may expect the input tokens to be held by
                                              // `payer`, `address(this)`, or some other address.
                                              // Compute the expected address and transfer the input tokens
                                              // there if necessary.
                                              state.from = _computeHopTarget(params, 0);
                                              // If the input tokens are currently held by `payer` but
                                              // the first hop expects them elsewhere, perform a `transferFrom`.
                                              if (!params.useSelfBalance && state.from != params.payer) {
                                                  _transferERC20TokensFrom(IERC20Token(params.tokens[0]), params.payer, state.from, params.sellAmount);
                                              }
                                              // If the input tokens are currently held by `address(this)` but
                                              // the first hop expects them elsewhere, perform a `transfer`.
                                              if (params.useSelfBalance && state.from != address(this)) {
                                                  _transferERC20Tokens(IERC20Token(params.tokens[0]), state.from, params.sellAmount);
                                              }
                                              // Iterate through the calls and execute each one.
                                              for (state.hopIndex = 0; state.hopIndex != params.calls.length; state.hopIndex++) {
                                                  MultiHopSellSubcall memory subcall = params.calls[state.hopIndex];
                                                  // Compute the recipient of the tokens that will be
                                                  // bought by the current hop.
                                                  state.to = _computeHopTarget(params, state.hopIndex + 1);
                                                  if (subcall.id == MultiplexSubcall.UniswapV2) {
                                                      _multiHopSellUniswapV2(state, params, subcall.data);
                                                  } else if (subcall.id == MultiplexSubcall.UniswapV3) {
                                                      _multiHopSellUniswapV3(state, params, subcall.data);
                                                  } else if (subcall.id == MultiplexSubcall.LiquidityProvider) {
                                                      _multiHopSellLiquidityProvider(state, params, subcall.data);
                                                  } else if (subcall.id == MultiplexSubcall.BatchSell) {
                                                      _nestedBatchSell(state, params, subcall.data);
                                                  } else if (subcall.id == MultiplexSubcall.OTC) {
                                                      _multiHopSellOtcOrder(state, params, subcall.data);
                                                  } else {
                                                      revert("MultiplexFeature::_executeMultiHopSell/INVALID_SUBCALL");
                                                  }
                                                  // The recipient of the current hop will be the source
                                                  // of tokens for the next hop.
                                                  state.from = state.to;
                                              }
                                          }
                                          function _nestedMultiHopSell(
                                              IMultiplexFeature.BatchSellState memory state,
                                              IMultiplexFeature.BatchSellParams memory params,
                                              bytes memory data,
                                              uint256 sellAmount
                                          ) private {
                                              MultiHopSellParams memory multiHopParams;
                                              // Decode the tokens and calls for the nested
                                              // multi-hop sell.
                                              (multiHopParams.tokens, multiHopParams.calls) = abi.decode(data, (address[], MultiHopSellSubcall[]));
                                              multiHopParams.sellAmount = sellAmount;
                                              // If the batch sell is using input tokens held by
                                              // `address(this)`, then so should the nested
                                              // multi-hop sell.
                                              multiHopParams.useSelfBalance = params.useSelfBalance;
                                              // Likewise, the recipient of the multi-hop sell is
                                              // equal to the recipient of its containing batch sell.
                                              multiHopParams.recipient = params.recipient;
                                              // The payer is the same too.
                                              multiHopParams.payer = params.payer;
                                              // Execute the nested multi-hop sell.
                                              uint256 outputTokenAmount = _executeMultiHopSell(multiHopParams).outputTokenAmount;
                                              // Increment the sold and bought amounts.
                                              state.soldAmount = state.soldAmount.safeAdd(sellAmount);
                                              state.boughtAmount = state.boughtAmount.safeAdd(outputTokenAmount);
                                          }
                                          function _nestedBatchSell(
                                              IMultiplexFeature.MultiHopSellState memory state,
                                              IMultiplexFeature.MultiHopSellParams memory params,
                                              bytes memory data
                                          ) private {
                                              BatchSellParams memory batchSellParams;
                                              // Decode the calls for the nested batch sell.
                                              batchSellParams.calls = abi.decode(data, (BatchSellSubcall[]));
                                              // The input and output tokens of the batch
                                              // sell are the current and next tokens in
                                              // `params.tokens`, respectively.
                                              batchSellParams.inputToken = IERC20Token(params.tokens[state.hopIndex]);
                                              batchSellParams.outputToken = IERC20Token(params.tokens[state.hopIndex + 1]);
                                              // The `sellAmount` for the batch sell is the
                                              // `outputTokenAmount` from the previous hop.
                                              batchSellParams.sellAmount = state.outputTokenAmount;
                                              // If the nested batch sell is the first hop
                                              // and `useSelfBalance` for the containing multi-
                                              // hop sell is false, the nested batch sell should
                                              // pull tokens from `payer` (so  `batchSellParams.useSelfBalance`
                                              // should be false). Otherwise `batchSellParams.useSelfBalance`
                                              // should be true.
                                              batchSellParams.useSelfBalance = state.hopIndex > 0 || params.useSelfBalance;
                                              // `state.to` has been populated with the address
                                              // that should receive the output tokens of the
                                              // batch sell.
                                              batchSellParams.recipient = state.to;
                                              // payer shound be the same too.
                                              batchSellParams.payer = params.payer;
                                              // Execute the nested batch sell.
                                              state.outputTokenAmount = _executeBatchSell(batchSellParams).boughtAmount;
                                          }
                                          // This function computes the "target" address of hop index `i` within
                                          // a multi-hop sell.
                                          // If `i == 0`, the target is the address which should hold the input
                                          // tokens prior to executing `calls[0]`. Otherwise, it is the address
                                          // that should receive `tokens[i]` upon executing `calls[i-1]`.
                                          function _computeHopTarget(MultiHopSellParams memory params, uint256 i) private view returns (address target) {
                                              if (i == params.calls.length) {
                                                  // The last call should send the output tokens to the
                                                  // multi-hop sell recipient.
                                                  target = params.recipient;
                                              } else {
                                                  MultiHopSellSubcall memory subcall = params.calls[i];
                                                  if (subcall.id == MultiplexSubcall.UniswapV2) {
                                                      // UniswapV2 (and Sushiswap) allow tokens to be
                                                      // transferred into the pair contract before `swap`
                                                      // is called, so we compute the pair contract's address.
                                                      (address[] memory tokens, bool isSushi) = abi.decode(subcall.data, (address[], bool));
                                                      target = _computeUniswapPairAddress(tokens[0], tokens[1], isSushi);
                                                  } else if (subcall.id == MultiplexSubcall.LiquidityProvider) {
                                                      // Similar to UniswapV2, LiquidityProvider contracts
                                                      // allow tokens to be transferred in before the swap
                                                      // is executed, so we the target is the address encoded
                                                      // in the subcall data.
                                                      (target, ) = abi.decode(subcall.data, (address, bytes));
                                                  } else if (
                                                      subcall.id == MultiplexSubcall.UniswapV3 ||
                                                      subcall.id == MultiplexSubcall.BatchSell ||
                                                      subcall.id == MultiplexSubcall.OTC
                                                  ) {
                                                      // UniswapV3 uses a callback to pull in the tokens being
                                                      // sold to it. The callback implemented in `UniswapV3Feature`
                                                      // can either:
                                                      // - call `transferFrom` to move tokens from `payer` to the
                                                      //   UniswapV3 pool, or
                                                      // - call `transfer` to move tokens from `address(this)` to the
                                                      //   UniswapV3 pool.
                                                      // A nested batch sell is similar, in that it can either:
                                                      // - use tokens from `payer`, or
                                                      // - use tokens held by `address(this)`.
                                                      // Suppose UniswapV3/BatchSell is the first call in the multi-hop
                                                      // path. The input tokens are either held by `payer`,
                                                      // or in the case of `multiplexMultiHopSellEthForToken` WETH is
                                                      // held by `address(this)`. The target is set accordingly.
                                                      // If this is _not_ the first call in the multi-hop path, we
                                                      // are dealing with an "intermediate" token in the multi-hop path,
                                                      // which `payer` may not have an allowance set for. Thus
                                                      // target must be set to `address(this)` for `i > 0`.
                                                      if (i == 0 && !params.useSelfBalance) {
                                                          target = params.payer;
                                                      } else {
                                                          target = address(this);
                                                      }
                                                  } else {
                                                      revert("MultiplexFeature::_computeHopTarget/INVALID_SUBCALL");
                                                  }
                                              }
                                              require(target != address(0), "MultiplexFeature::_computeHopTarget/TARGET_IS_NULL");
                                          }
                                          // If `rawAmount` encodes a proportion of `totalSellAmount`, this function
                                          // converts it to an absolute quantity. Caps the normalized amount to
                                          // the remaining sell amount (`totalSellAmount - soldAmount`).
                                          function _normalizeSellAmount(
                                              uint256 rawAmount,
                                              uint256 totalSellAmount,
                                              uint256 soldAmount
                                          ) private pure returns (uint256 normalized) {
                                              if ((rawAmount & HIGH_BIT) == HIGH_BIT) {
                                                  // If the high bit of `rawAmount` is set then the lower 255 bits
                                                  // specify a fraction of `totalSellAmount`.
                                                  return
                                                      LibSafeMathV06.min256(
                                                          (totalSellAmount * LibSafeMathV06.min256(rawAmount & LOWER_255_BITS, 1e18)) / 1e18,
                                                          totalSellAmount.safeSub(soldAmount)
                                                      );
                                              } else {
                                                  return LibSafeMathV06.min256(rawAmount, totalSellAmount.safeSub(soldAmount));
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity >=0.6.5 <0.9;
                                      interface IERC20Token {
                                          event Transfer(address indexed from, address indexed to, uint256 value);
                                          event Approval(address indexed owner, address indexed spender, uint256 value);
                                          /// @dev send `value` token to `to` from `msg.sender`
                                          /// @param to The address of the recipient
                                          /// @param value The amount of token to be transferred
                                          /// @return True if transfer was successful
                                          function transfer(address to, uint256 value) external returns (bool);
                                          /// @dev send `value` token to `to` from `from` on the condition it is approved by `from`
                                          /// @param from The address of the sender
                                          /// @param to The address of the recipient
                                          /// @param value The amount of token to be transferred
                                          /// @return True if transfer was successful
                                          function transferFrom(address from, address to, uint256 value) external returns (bool);
                                          /// @dev `msg.sender` approves `spender` to spend `value` tokens
                                          /// @param spender The address of the account able to transfer the tokens
                                          /// @param value The amount of wei to be approved for transfer
                                          /// @return Always true if the call has enough gas to complete execution
                                          function approve(address spender, uint256 value) external returns (bool);
                                          /// @dev Query total supply of token
                                          /// @return Total supply of token
                                          function totalSupply() external view returns (uint256);
                                          /// @dev Get the balance of `owner`.
                                          /// @param owner The address from which the balance will be retrieved
                                          /// @return Balance of owner
                                          function balanceOf(address owner) external view returns (uint256);
                                          /// @dev Get the allowance for `spender` to spend from `owner`.
                                          /// @param owner The address of the account owning tokens
                                          /// @param spender The address of the account able to transfer the tokens
                                          /// @return Amount of remaining tokens allowed to spent
                                          function allowance(address owner, address spender) external view returns (uint256);
                                          /// @dev Get the number of decimals this token has.
                                          function decimals() external view returns (uint8);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./IERC20Token.sol";
                                      interface IEtherToken is IERC20Token {
                                          /// @dev Wrap ether.
                                          function deposit() external payable;
                                          /// @dev Unwrap ether.
                                          function withdraw(uint256 amount) external;
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./errors/LibRichErrorsV06.sol";
                                      import "./errors/LibSafeMathRichErrorsV06.sol";
                                      library LibSafeMathV06 {
                                          function safeMul(uint256 a, uint256 b) internal pure returns (uint256) {
                                              if (a == 0) {
                                                  return 0;
                                              }
                                              uint256 c = a * b;
                                              if (c / a != b) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.MULTIPLICATION_OVERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return c;
                                          }
                                          function safeDiv(uint256 a, uint256 b) internal pure returns (uint256) {
                                              if (b == 0) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.DIVISION_BY_ZERO,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              uint256 c = a / b;
                                              return c;
                                          }
                                          function safeSub(uint256 a, uint256 b) internal pure returns (uint256) {
                                              if (b > a) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.SUBTRACTION_UNDERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return a - b;
                                          }
                                          function safeAdd(uint256 a, uint256 b) internal pure returns (uint256) {
                                              uint256 c = a + b;
                                              if (c < a) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.ADDITION_OVERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return c;
                                          }
                                          function max256(uint256 a, uint256 b) internal pure returns (uint256) {
                                              return a >= b ? a : b;
                                          }
                                          function min256(uint256 a, uint256 b) internal pure returns (uint256) {
                                              return a < b ? a : b;
                                          }
                                          function safeMul128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              if (a == 0) {
                                                  return 0;
                                              }
                                              uint128 c = a * b;
                                              if (c / a != b) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.MULTIPLICATION_OVERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return c;
                                          }
                                          function safeDiv128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              if (b == 0) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.DIVISION_BY_ZERO,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              uint128 c = a / b;
                                              return c;
                                          }
                                          function safeSub128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              if (b > a) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.SUBTRACTION_UNDERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return a - b;
                                          }
                                          function safeAdd128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              uint128 c = a + b;
                                              if (c < a) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.ADDITION_OVERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return c;
                                          }
                                          function max128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              return a >= b ? a : b;
                                          }
                                          function min128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              return a < b ? a : b;
                                          }
                                          function safeDowncastToUint128(uint256 a) internal pure returns (uint128) {
                                              if (a > type(uint128).max) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256DowncastError(
                                                          LibSafeMathRichErrorsV06.DowncastErrorCodes.VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT128,
                                                          a
                                                      )
                                                  );
                                              }
                                              return uint128(a);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibRichErrorsV06 {
                                          // bytes4(keccak256("Error(string)"))
                                          bytes4 internal constant STANDARD_ERROR_SELECTOR = 0x08c379a0;
                                          /// @dev ABI encode a standard, string revert error payload.
                                          ///      This is the same payload that would be included by a `revert(string)`
                                          ///      solidity statement. It has the function signature `Error(string)`.
                                          /// @param message The error string.
                                          /// @return The ABI encoded error.
                                          function StandardError(string memory message) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(STANDARD_ERROR_SELECTOR, bytes(message));
                                          }
                                          /// @dev Reverts an encoded rich revert reason `errorData`.
                                          /// @param errorData ABI encoded error data.
                                          function rrevert(bytes memory errorData) internal pure {
                                              assembly {
                                                  revert(add(errorData, 0x20), mload(errorData))
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibSafeMathRichErrorsV06 {
                                          // bytes4(keccak256("Uint256BinOpError(uint8,uint256,uint256)"))
                                          bytes4 internal constant UINT256_BINOP_ERROR_SELECTOR = 0xe946c1bb;
                                          // bytes4(keccak256("Uint256DowncastError(uint8,uint256)"))
                                          bytes4 internal constant UINT256_DOWNCAST_ERROR_SELECTOR = 0xc996af7b;
                                          enum BinOpErrorCodes {
                                              ADDITION_OVERFLOW,
                                              MULTIPLICATION_OVERFLOW,
                                              SUBTRACTION_UNDERFLOW,
                                              DIVISION_BY_ZERO
                                          }
                                          enum DowncastErrorCodes {
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT32,
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT64,
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT96,
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT128
                                          }
                                          function Uint256BinOpError(BinOpErrorCodes errorCode, uint256 a, uint256 b) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(UINT256_BINOP_ERROR_SELECTOR, errorCode, a, b);
                                          }
                                          function Uint256DowncastError(DowncastErrorCodes errorCode, uint256 a) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(UINT256_DOWNCAST_ERROR_SELECTOR, errorCode, a);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "../vendor/ILiquidityProvider.sol";
                                      interface ILiquidityProviderSandbox {
                                          /// @dev Calls `sellTokenForToken` on the given `provider` contract to
                                          ///      trigger a trade.
                                          /// @param provider The address of the on-chain liquidity provider.
                                          /// @param inputToken The token being sold.
                                          /// @param outputToken The token being bought.
                                          /// @param recipient The recipient of the bought tokens.
                                          /// @param minBuyAmount The minimum acceptable amount of `outputToken` to buy.
                                          /// @param auxiliaryData Auxiliary data supplied to the `provider` contract.
                                          function executeSellTokenForToken(
                                              ILiquidityProvider provider,
                                              IERC20Token inputToken,
                                              IERC20Token outputToken,
                                              address recipient,
                                              uint256 minBuyAmount,
                                              bytes calldata auxiliaryData
                                          ) external;
                                          /// @dev Calls `sellEthForToken` on the given `provider` contract to
                                          ///      trigger a trade.
                                          /// @param provider The address of the on-chain liquidity provider.
                                          /// @param outputToken The token being bought.
                                          /// @param recipient The recipient of the bought tokens.
                                          /// @param minBuyAmount The minimum acceptable amount of `outputToken` to buy.
                                          /// @param auxiliaryData Auxiliary data supplied to the `provider` contract.
                                          function executeSellEthForToken(
                                              ILiquidityProvider provider,
                                              IERC20Token outputToken,
                                              address recipient,
                                              uint256 minBuyAmount,
                                              bytes calldata auxiliaryData
                                          ) external;
                                          /// @dev Calls `sellTokenForEth` on the given `provider` contract to
                                          ///      trigger a trade.
                                          /// @param provider The address of the on-chain liquidity provider.
                                          /// @param inputToken The token being sold.
                                          /// @param recipient The recipient of the bought tokens.
                                          /// @param minBuyAmount The minimum acceptable amount of ETH to buy.
                                          /// @param auxiliaryData Auxiliary data supplied to the `provider` contract.
                                          function executeSellTokenForEth(
                                              ILiquidityProvider provider,
                                              IERC20Token inputToken,
                                              address recipient,
                                              uint256 minBuyAmount,
                                              bytes calldata auxiliaryData
                                          ) external;
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      interface ILiquidityProvider {
                                          /// @dev An optional event an LP can emit for each fill against a source.
                                          /// @param inputToken The input token.
                                          /// @param outputToken The output token.
                                          /// @param inputTokenAmount How much input token was sold.
                                          /// @param outputTokenAmount How much output token was bought.
                                          /// @param sourceId A bytes32 encoded ascii source ID. E.g., `bytes32('Curve')`/
                                          /// @param sourceAddress An optional address associated with the source (e.g, a curve pool).
                                          /// @param sourceId A bytes32 encoded ascii source ID. E.g., `bytes32('Curve')`/
                                          /// @param sourceAddress An optional address associated with the source (e.g, a curve pool).
                                          /// @param sender The caller of the LP.
                                          /// @param recipient The recipient of the output tokens.
                                          event LiquidityProviderFill(
                                              IERC20Token inputToken,
                                              IERC20Token outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 outputTokenAmount,
                                              bytes32 sourceId,
                                              address sourceAddress,
                                              address sender,
                                              address recipient
                                          );
                                          /// @dev Trades `inputToken` for `outputToken`. The amount of `inputToken`
                                          ///      to sell must be transferred to the contract prior to calling this
                                          ///      function to trigger the trade.
                                          /// @param inputToken The token being sold.
                                          /// @param outputToken The token being bought.
                                          /// @param recipient The recipient of the bought tokens.
                                          /// @param minBuyAmount The minimum acceptable amount of `outputToken` to buy.
                                          /// @param auxiliaryData Arbitrary auxiliary data supplied to the contract.
                                          /// @return boughtAmount The amount of `outputToken` bought.
                                          function sellTokenForToken(
                                              IERC20Token inputToken,
                                              IERC20Token outputToken,
                                              address recipient,
                                              uint256 minBuyAmount,
                                              bytes calldata auxiliaryData
                                          ) external returns (uint256 boughtAmount);
                                          /// @dev Trades ETH for token. ETH must either be attached to this function
                                          ///      call or sent to the contract prior to calling this function to
                                          ///      trigger the trade.
                                          /// @param outputToken The token being bought.
                                          /// @param recipient The recipient of the bought tokens.
                                          /// @param minBuyAmount The minimum acceptable amount of `outputToken` to buy.
                                          /// @param auxiliaryData Arbitrary auxiliary data supplied to the contract.
                                          /// @return boughtAmount The amount of `outputToken` bought.
                                          function sellEthForToken(
                                              IERC20Token outputToken,
                                              address recipient,
                                              uint256 minBuyAmount,
                                              bytes calldata auxiliaryData
                                          ) external payable returns (uint256 boughtAmount);
                                          /// @dev Trades token for ETH. The token must be sent to the contract prior
                                          ///      to calling this function to trigger the trade.
                                          /// @param inputToken The token being sold.
                                          /// @param recipient The recipient of the bought tokens.
                                          /// @param minBuyAmount The minimum acceptable amount of ETH to buy.
                                          /// @param auxiliaryData Arbitrary auxiliary data supplied to the contract.
                                          /// @return boughtAmount The amount of ETH bought.
                                          function sellTokenForEth(
                                              IERC20Token inputToken,
                                              address payable recipient,
                                              uint256 minBuyAmount,
                                              bytes calldata auxiliaryData
                                          ) external returns (uint256 boughtAmount);
                                          /// @dev Quotes the amount of `outputToken` that would be obtained by
                                          ///      selling `sellAmount` of `inputToken`.
                                          /// @param inputToken Address of the taker token (what to sell). Use
                                          ///        the wETH address if selling ETH.
                                          /// @param outputToken Address of the maker token (what to buy). Use
                                          ///        the wETH address if buying ETH.
                                          /// @param sellAmount Amount of `inputToken` to sell.
                                          /// @return outputTokenAmount Amount of `outputToken` that would be obtained.
                                          function getSellQuote(
                                              IERC20Token inputToken,
                                              IERC20Token outputToken,
                                              uint256 sellAmount
                                          ) external view returns (uint256 outputTokenAmount);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibCommonRichErrors.sol";
                                      import "../errors/LibOwnableRichErrors.sol";
                                      import "../features/interfaces/IOwnableFeature.sol";
                                      import "../features/interfaces/ISimpleFunctionRegistryFeature.sol";
                                      /// @dev Common feature utilities.
                                      abstract contract FixinCommon {
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev The implementation address of this feature.
                                          address internal immutable _implementation;
                                          /// @dev The caller must be this contract.
                                          modifier onlySelf() virtual {
                                              if (msg.sender != address(this)) {
                                                  LibCommonRichErrors.OnlyCallableBySelfError(msg.sender).rrevert();
                                              }
                                              _;
                                          }
                                          /// @dev The caller of this function must be the owner.
                                          modifier onlyOwner() virtual {
                                              {
                                                  address owner = IOwnableFeature(address(this)).owner();
                                                  if (msg.sender != owner) {
                                                      LibOwnableRichErrors.OnlyOwnerError(msg.sender, owner).rrevert();
                                                  }
                                              }
                                              _;
                                          }
                                          constructor() internal {
                                              // Remember this feature's original address.
                                              _implementation = address(this);
                                          }
                                          /// @dev Registers a function implemented by this feature at `_implementation`.
                                          ///      Can and should only be called within a `migrate()`.
                                          /// @param selector The selector of the function whose implementation
                                          ///        is at `_implementation`.
                                          function _registerFeatureFunction(bytes4 selector) internal {
                                              ISimpleFunctionRegistryFeature(address(this)).extend(selector, _implementation);
                                          }
                                          /// @dev Encode a feature version as a `uint256`.
                                          /// @param major The major version number of the feature.
                                          /// @param minor The minor version number of the feature.
                                          /// @param revision The revision number of the feature.
                                          /// @return encodedVersion The encoded version number.
                                          function _encodeVersion(
                                              uint32 major,
                                              uint32 minor,
                                              uint32 revision
                                          ) internal pure returns (uint256 encodedVersion) {
                                              return (uint256(major) << 64) | (uint256(minor) << 32) | uint256(revision);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibCommonRichErrors {
                                          function OnlyCallableBySelfError(address sender) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("OnlyCallableBySelfError(address)")), sender);
                                          }
                                          function IllegalReentrancyError(bytes4 selector, uint256 reentrancyFlags) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("IllegalReentrancyError(bytes4,uint256)")),
                                                      selector,
                                                      reentrancyFlags
                                                  );
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibOwnableRichErrors {
                                          function OnlyOwnerError(address sender, address owner) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("OnlyOwnerError(address,address)")), sender, owner);
                                          }
                                          function TransferOwnerToZeroError() internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("TransferOwnerToZeroError()")));
                                          }
                                          function MigrateCallFailedError(address target, bytes memory resultData) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("MigrateCallFailedError(address,bytes)")), target, resultData);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/interfaces/IOwnableV06.sol";
                                      /// @dev Owner management and migration features.
                                      interface IOwnableFeature is IOwnableV06 {
                                          /// @dev Emitted when `migrate()` is called.
                                          /// @param caller The caller of `migrate()`.
                                          /// @param migrator The migration contract.
                                          /// @param newOwner The address of the new owner.
                                          event Migrated(address caller, address migrator, address newOwner);
                                          /// @dev Execute a migration function in the context of the ZeroEx contract.
                                          ///      The result of the function being called should be the magic bytes
                                          ///      0x2c64c5ef (`keccack('MIGRATE_SUCCESS')`). Only callable by the owner.
                                          ///      The owner will be temporarily set to `address(this)` inside the call.
                                          ///      Before returning, the owner will be set to `newOwner`.
                                          /// @param target The migrator contract address.
                                          /// @param newOwner The address of the new owner.
                                          /// @param data The call data.
                                          function migrate(address target, bytes calldata data, address newOwner) external;
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      interface IOwnableV06 {
                                          /// @dev Emitted by Ownable when ownership is transferred.
                                          /// @param previousOwner The previous owner of the contract.
                                          /// @param newOwner The new owner of the contract.
                                          event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
                                          /// @dev Transfers ownership of the contract to a new address.
                                          /// @param newOwner The address that will become the owner.
                                          function transferOwnership(address newOwner) external;
                                          /// @dev The owner of this contract.
                                          /// @return ownerAddress The owner address.
                                          function owner() external view returns (address ownerAddress);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Basic registry management features.
                                      interface ISimpleFunctionRegistryFeature {
                                          /// @dev A function implementation was updated via `extend()` or `rollback()`.
                                          /// @param selector The function selector.
                                          /// @param oldImpl The implementation contract address being replaced.
                                          /// @param newImpl The replacement implementation contract address.
                                          event ProxyFunctionUpdated(bytes4 indexed selector, address oldImpl, address newImpl);
                                          /// @dev Roll back to a prior implementation of a function.
                                          /// @param selector The function selector.
                                          /// @param targetImpl The address of an older implementation of the function.
                                          function rollback(bytes4 selector, address targetImpl) external;
                                          /// @dev Register or replace a function.
                                          /// @param selector The function selector.
                                          /// @param impl The implementation contract for the function.
                                          function extend(bytes4 selector, address impl) external;
                                          /// @dev Retrieve the length of the rollback history for a function.
                                          /// @param selector The function selector.
                                          /// @return rollbackLength The number of items in the rollback history for
                                          ///         the function.
                                          function getRollbackLength(bytes4 selector) external view returns (uint256 rollbackLength);
                                          /// @dev Retrieve an entry in the rollback history for a function.
                                          /// @param selector The function selector.
                                          /// @param idx The index in the rollback history.
                                          /// @return impl An implementation address for the function at
                                          ///         index `idx`.
                                          function getRollbackEntryAtIndex(bytes4 selector, uint256 idx) external view returns (address impl);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibCommonRichErrors.sol";
                                      import "../errors/LibOwnableRichErrors.sol";
                                      /// @dev EIP712 helpers for features.
                                      abstract contract FixinEIP712 {
                                          /// @dev The domain hash separator for the entire exchange proxy.
                                          bytes32 public immutable EIP712_DOMAIN_SEPARATOR;
                                          constructor(address zeroExAddress) internal {
                                              // Compute `EIP712_DOMAIN_SEPARATOR`
                                              {
                                                  uint256 chainId;
                                                  assembly {
                                                      chainId := chainid()
                                                  }
                                                  EIP712_DOMAIN_SEPARATOR = keccak256(
                                                      abi.encode(
                                                          keccak256(
                                                              "EIP712Domain("
                                                              "string name,"
                                                              "string version,"
                                                              "uint256 chainId,"
                                                              "address verifyingContract"
                                                              ")"
                                                          ),
                                                          keccak256("ZeroEx"),
                                                          keccak256("1.0.0"),
                                                          chainId,
                                                          zeroExAddress
                                                      )
                                                  );
                                              }
                                          }
                                          function _getEIP712Hash(bytes32 structHash) internal view returns (bytes32 eip712Hash) {
                                              return keccak256(abi.encodePacked(hex"1901", EIP712_DOMAIN_SEPARATOR, structHash));
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibOwnableRichErrors.sol";
                                      library LibMigrate {
                                          /// @dev Magic bytes returned by a migrator to indicate success.
                                          ///      This is `keccack('MIGRATE_SUCCESS')`.
                                          bytes4 internal constant MIGRATE_SUCCESS = 0x2c64c5ef;
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev Perform a delegatecall and ensure it returns the magic bytes.
                                          /// @param target The call target.
                                          /// @param data The call data.
                                          function delegatecallMigrateFunction(address target, bytes memory data) internal {
                                              (bool success, bytes memory resultData) = target.delegatecall(data);
                                              if (!success || resultData.length != 32 || abi.decode(resultData, (bytes4)) != MIGRATE_SUCCESS) {
                                                  LibOwnableRichErrors.MigrateCallFailedError(target, resultData).rrevert();
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Basic interface for a feature contract.
                                      interface IFeature {
                                          /// @dev The name of this feature set.
                                          function FEATURE_NAME() external view returns (string memory name);
                                          /// @dev The version of this feature set.
                                          function FEATURE_VERSION() external view returns (uint256 version);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      interface IMultiplexFeature {
                                          // Identifies the type of subcall.
                                          enum MultiplexSubcall {
                                              Invalid,
                                              RFQ,
                                              OTC,
                                              UniswapV2,
                                              UniswapV3,
                                              LiquidityProvider,
                                              TransformERC20,
                                              BatchSell,
                                              MultiHopSell
                                          }
                                          // Parameters for a batch sell.
                                          struct BatchSellParams {
                                              // The token being sold.
                                              IERC20Token inputToken;
                                              // The token being bought.
                                              IERC20Token outputToken;
                                              // The amount of `inputToken` to sell.
                                              uint256 sellAmount;
                                              // The nested calls to perform.
                                              BatchSellSubcall[] calls;
                                              // Whether to use the Exchange Proxy's balance
                                              // of input tokens.
                                              bool useSelfBalance;
                                              // The recipient of the bought output tokens.
                                              address recipient;
                                              // The sender of the input tokens.
                                              address payer;
                                          }
                                          // Represents a constituent call of a batch sell.
                                          struct BatchSellSubcall {
                                              // The function to call.
                                              MultiplexSubcall id;
                                              // Amount of input token to sell. If the highest bit is 1,
                                              // this value represents a proportion of the total
                                              // `sellAmount` of the batch sell. See `_normalizeSellAmount`
                                              // for details.
                                              uint256 sellAmount;
                                              // ABI-encoded parameters needed to perform the call.
                                              bytes data;
                                          }
                                          // Parameters for a multi-hop sell.
                                          struct MultiHopSellParams {
                                              // The sell path, i.e.
                                              // tokens = [inputToken, hopToken1, ..., hopTokenN, outputToken]
                                              address[] tokens;
                                              // The amount of `tokens[0]` to sell.
                                              uint256 sellAmount;
                                              // The nested calls to perform.
                                              MultiHopSellSubcall[] calls;
                                              // Whether to use the Exchange Proxy's balance
                                              // of input tokens.
                                              bool useSelfBalance;
                                              // The recipient of the bought output tokens.
                                              address recipient;
                                              // The sender of the input tokens.
                                              address payer;
                                          }
                                          // Represents a constituent call of a multi-hop sell.
                                          struct MultiHopSellSubcall {
                                              // The function to call.
                                              MultiplexSubcall id;
                                              // ABI-encoded parameters needed to perform the call.
                                              bytes data;
                                          }
                                          struct BatchSellState {
                                              // Tracks the amount of input token sold.
                                              uint256 soldAmount;
                                              // Tracks the amount of output token bought.
                                              uint256 boughtAmount;
                                          }
                                          struct MultiHopSellState {
                                              // This variable is used for the input and output amounts of
                                              // each hop. After the final hop, this will contain the output
                                              // amount of the multi-hop sell.
                                              uint256 outputTokenAmount;
                                              // For each hop in a multi-hop sell, `from` is the
                                              // address that holds the input tokens of the hop,
                                              // `to` is the address that receives the output tokens
                                              // of the hop.
                                              // See `_computeHopTarget` for details.
                                              address from;
                                              address to;
                                              // The index of the current hop in the multi-hop chain.
                                              uint256 hopIndex;
                                          }
                                          /// @dev Sells attached ETH for `outputToken` using the provided
                                          ///      calls.
                                          /// @param outputToken The token to buy.
                                          /// @param calls The calls to use to sell the attached ETH.
                                          /// @param minBuyAmount The minimum amount of `outputToken` that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of `outputToken` bought.
                                          function multiplexBatchSellEthForToken(
                                              IERC20Token outputToken,
                                              BatchSellSubcall[] calldata calls,
                                              uint256 minBuyAmount
                                          ) external payable returns (uint256 boughtAmount);
                                          /// @dev Sells `sellAmount` of the given `inputToken` for ETH
                                          ///      using the provided calls.
                                          /// @param inputToken The token to sell.
                                          /// @param calls The calls to use to sell the input tokens.
                                          /// @param sellAmount The amount of `inputToken` to sell.
                                          /// @param minBuyAmount The minimum amount of ETH that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of ETH bought.
                                          function multiplexBatchSellTokenForEth(
                                              IERC20Token inputToken,
                                              BatchSellSubcall[] calldata calls,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount
                                          ) external returns (uint256 boughtAmount);
                                          /// @dev Sells `sellAmount` of the given `inputToken` for
                                          ///      `outputToken` using the provided calls.
                                          /// @param inputToken The token to sell.
                                          /// @param outputToken The token to buy.
                                          /// @param calls The calls to use to sell the input tokens.
                                          /// @param sellAmount The amount of `inputToken` to sell.
                                          /// @param minBuyAmount The minimum amount of `outputToken`
                                          ///        that must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of `outputToken` bought.
                                          function multiplexBatchSellTokenForToken(
                                              IERC20Token inputToken,
                                              IERC20Token outputToken,
                                              BatchSellSubcall[] calldata calls,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount
                                          ) external returns (uint256 boughtAmount);
                                          /// @dev Executes a multiplex BatchSell using the given
                                          ///      parameters. Internal only.
                                          /// @param params The parameters for the BatchSell.
                                          /// @param minBuyAmount The minimum amount of `params.outputToken`
                                          ///        that must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of `params.outputToken` bought.
                                          function _multiplexBatchSell(
                                              BatchSellParams memory params,
                                              uint256 minBuyAmount
                                          ) external returns (uint256 boughtAmount);
                                          /// @dev Sells attached ETH via the given sequence of tokens
                                          ///      and calls. `tokens[0]` must be WETH.
                                          ///      The last token in `tokens` is the output token that
                                          ///      will ultimately be sent to `msg.sender`
                                          /// @param tokens The sequence of tokens to use for the sell,
                                          ///        i.e. `tokens[i]` will be sold for `tokens[i+1]` via
                                          ///        `calls[i]`.
                                          /// @param calls The sequence of calls to use for the sell.
                                          /// @param minBuyAmount The minimum amount of output tokens that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of output tokens bought.
                                          function multiplexMultiHopSellEthForToken(
                                              address[] calldata tokens,
                                              MultiHopSellSubcall[] calldata calls,
                                              uint256 minBuyAmount
                                          ) external payable returns (uint256 boughtAmount);
                                          /// @dev Sells `sellAmount` of the input token (`tokens[0]`)
                                          ///      for ETH via the given sequence of tokens and calls.
                                          ///      The last token in `tokens` must be WETH.
                                          /// @param tokens The sequence of tokens to use for the sell,
                                          ///        i.e. `tokens[i]` will be sold for `tokens[i+1]` via
                                          ///        `calls[i]`.
                                          /// @param calls The sequence of calls to use for the sell.
                                          /// @param minBuyAmount The minimum amount of ETH that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of ETH bought.
                                          function multiplexMultiHopSellTokenForEth(
                                              address[] calldata tokens,
                                              MultiHopSellSubcall[] calldata calls,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount
                                          ) external returns (uint256 boughtAmount);
                                          /// @dev Sells `sellAmount` of the input token (`tokens[0]`)
                                          ///      via the given sequence of tokens and calls.
                                          ///      The last token in `tokens` is the output token that
                                          ///      will ultimately be sent to `msg.sender`
                                          /// @param tokens The sequence of tokens to use for the sell,
                                          ///        i.e. `tokens[i]` will be sold for `tokens[i+1]` via
                                          ///        `calls[i]`.
                                          /// @param calls The sequence of calls to use for the sell.
                                          /// @param minBuyAmount The minimum amount of output tokens that
                                          ///        must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of output tokens bought.
                                          function multiplexMultiHopSellTokenForToken(
                                              address[] calldata tokens,
                                              MultiHopSellSubcall[] calldata calls,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount
                                          ) external returns (uint256 boughtAmount);
                                          /// @dev Executes a multiplex MultiHopSell using the given
                                          ///      parameters. Internal only.
                                          /// @param params The parameters for the MultiHopSell.
                                          /// @param minBuyAmount The minimum amount of the output token
                                          ///        that must be bought for this function to not revert.
                                          /// @return boughtAmount The amount of the output token bought.
                                          function _multiplexMultiHopSell(
                                              MultiHopSellParams memory params,
                                              uint256 minBuyAmount
                                          ) external returns (uint256 boughtAmount);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "@0x/contracts-erc20/src/v06/LibERC20TokenV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../../external/ILiquidityProviderSandbox.sol";
                                      import "../../fixins/FixinCommon.sol";
                                      import "../../fixins/FixinTokenSpender.sol";
                                      import "../../vendor/ILiquidityProvider.sol";
                                      import "../interfaces/IMultiplexFeature.sol";
                                      abstract contract MultiplexLiquidityProvider is FixinCommon, FixinTokenSpender {
                                          using LibERC20TokenV06 for IERC20Token;
                                          using LibSafeMathV06 for uint256;
                                          // Same event fired by LiquidityProviderFeature
                                          event LiquidityProviderSwap(
                                              address inputToken,
                                              address outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 outputTokenAmount,
                                              address provider,
                                              address recipient
                                          );
                                          /// @dev The sandbox contract address.
                                          ILiquidityProviderSandbox private immutable SANDBOX;
                                          constructor(ILiquidityProviderSandbox sandbox) internal {
                                              SANDBOX = sandbox;
                                          }
                                          // A payable external function that we can delegatecall to
                                          // swallow reverts and roll back the input token transfer.
                                          function _batchSellLiquidityProviderExternal(
                                              IMultiplexFeature.BatchSellParams calldata params,
                                              bytes calldata wrappedCallData,
                                              uint256 sellAmount
                                          ) external payable returns (uint256 boughtAmount) {
                                              // Revert if not a delegatecall.
                                              require(
                                                  address(this) != _implementation,
                                                  "MultiplexLiquidityProvider::_batchSellLiquidityProviderExternal/ONLY_DELEGATECALL"
                                              );
                                              // Decode the provider address and auxiliary data.
                                              (address provider, bytes memory auxiliaryData) = abi.decode(wrappedCallData, (address, bytes));
                                              if (params.useSelfBalance) {
                                                  // If `useSelfBalance` is true, use the input tokens
                                                  // held by `address(this)`.
                                                  _transferERC20Tokens(params.inputToken, provider, sellAmount);
                                              } else {
                                                  // Otherwise, transfer the input tokens from `msg.sender`.
                                                  _transferERC20TokensFrom(params.inputToken, params.payer, provider, sellAmount);
                                              }
                                              // Cache the recipient's balance of the output token.
                                              uint256 balanceBefore = params.outputToken.balanceOf(params.recipient);
                                              // Execute the swap.
                                              SANDBOX.executeSellTokenForToken(
                                                  ILiquidityProvider(provider),
                                                  params.inputToken,
                                                  params.outputToken,
                                                  params.recipient,
                                                  0,
                                                  auxiliaryData
                                              );
                                              // Compute amount of output token received by the
                                              // recipient.
                                              boughtAmount = params.outputToken.balanceOf(params.recipient).safeSub(balanceBefore);
                                              emit LiquidityProviderSwap(
                                                  address(params.inputToken),
                                                  address(params.outputToken),
                                                  sellAmount,
                                                  boughtAmount,
                                                  provider,
                                                  params.recipient
                                              );
                                          }
                                          function _batchSellLiquidityProvider(
                                              IMultiplexFeature.BatchSellState memory state,
                                              IMultiplexFeature.BatchSellParams memory params,
                                              bytes memory wrappedCallData,
                                              uint256 sellAmount
                                          ) internal {
                                              // Swallow reverts
                                              (bool success, bytes memory resultData) = _implementation.delegatecall(
                                                  abi.encodeWithSelector(
                                                      this._batchSellLiquidityProviderExternal.selector,
                                                      params,
                                                      wrappedCallData,
                                                      sellAmount
                                                  )
                                              );
                                              if (success) {
                                                  // Decode the output token amount on success.
                                                  uint256 boughtAmount = abi.decode(resultData, (uint256));
                                                  // Increment the sold and bought amounts.
                                                  state.soldAmount = state.soldAmount.safeAdd(sellAmount);
                                                  state.boughtAmount = state.boughtAmount.safeAdd(boughtAmount);
                                              }
                                          }
                                          // This function is called after tokens have already been transferred
                                          // into the liquidity provider contract (in the previous hop).
                                          function _multiHopSellLiquidityProvider(
                                              IMultiplexFeature.MultiHopSellState memory state,
                                              IMultiplexFeature.MultiHopSellParams memory params,
                                              bytes memory wrappedCallData
                                          ) internal {
                                              IERC20Token inputToken = IERC20Token(params.tokens[state.hopIndex]);
                                              IERC20Token outputToken = IERC20Token(params.tokens[state.hopIndex + 1]);
                                              // Decode the provider address and auxiliary data.
                                              (address provider, bytes memory auxiliaryData) = abi.decode(wrappedCallData, (address, bytes));
                                              // Cache the recipient's balance of the output token.
                                              uint256 balanceBefore = outputToken.balanceOf(state.to);
                                              // Execute the swap.
                                              SANDBOX.executeSellTokenForToken(
                                                  ILiquidityProvider(provider),
                                                  inputToken,
                                                  outputToken,
                                                  state.to,
                                                  0,
                                                  auxiliaryData
                                              );
                                              // The previous `ouputTokenAmount` was effectively the
                                              // input amount for this call. Cache the value before
                                              // overwriting it with the new output token amount so
                                              // that both the input and ouput amounts can be in the
                                              // `LiquidityProviderSwap` event.
                                              uint256 sellAmount = state.outputTokenAmount;
                                              // Compute amount of output token received by the
                                              // recipient.
                                              state.outputTokenAmount = outputToken.balanceOf(state.to).safeSub(balanceBefore);
                                              emit LiquidityProviderSwap(
                                                  address(inputToken),
                                                  address(outputToken),
                                                  sellAmount,
                                                  state.outputTokenAmount,
                                                  provider,
                                                  state.to
                                              );
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
                                      import "../IERC20Token.sol";
                                      library LibERC20TokenV06 {
                                          bytes private constant DECIMALS_CALL_DATA = hex"313ce567";
                                          /// @dev Calls `IERC20Token(token).approve()`.
                                          ///      Reverts if the return data is invalid or the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param spender The address that receives an allowance.
                                          /// @param allowance The allowance to set.
                                          function compatApprove(IERC20Token token, address spender, uint256 allowance) internal {
                                              bytes memory callData = abi.encodeWithSelector(token.approve.selector, spender, allowance);
                                              _callWithOptionalBooleanResult(address(token), callData);
                                          }
                                          /// @dev Calls `IERC20Token(token).approve()` and sets the allowance to the
                                          ///      maximum if the current approval is not already >= an amount.
                                          ///      Reverts if the return data is invalid or the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param spender The address that receives an allowance.
                                          /// @param amount The minimum allowance needed.
                                          function approveIfBelow(IERC20Token token, address spender, uint256 amount) internal {
                                              if (token.allowance(address(this), spender) < amount) {
                                                  compatApprove(token, spender, uint256(-1));
                                              }
                                          }
                                          /// @dev Calls `IERC20Token(token).transfer()`.
                                          ///      Reverts if the return data is invalid or the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param to The address that receives the tokens
                                          /// @param amount Number of tokens to transfer.
                                          function compatTransfer(IERC20Token token, address to, uint256 amount) internal {
                                              bytes memory callData = abi.encodeWithSelector(token.transfer.selector, to, amount);
                                              _callWithOptionalBooleanResult(address(token), callData);
                                          }
                                          /// @dev Calls `IERC20Token(token).transferFrom()`.
                                          ///      Reverts if the return data is invalid or the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param from The owner of the tokens.
                                          /// @param to The address that receives the tokens
                                          /// @param amount Number of tokens to transfer.
                                          function compatTransferFrom(IERC20Token token, address from, address to, uint256 amount) internal {
                                              bytes memory callData = abi.encodeWithSelector(token.transferFrom.selector, from, to, amount);
                                              _callWithOptionalBooleanResult(address(token), callData);
                                          }
                                          /// @dev Retrieves the number of decimals for a token.
                                          ///      Returns `18` if the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @return tokenDecimals The number of decimals places for the token.
                                          function compatDecimals(IERC20Token token) internal view returns (uint8 tokenDecimals) {
                                              tokenDecimals = 18;
                                              (bool didSucceed, bytes memory resultData) = address(token).staticcall(DECIMALS_CALL_DATA);
                                              if (didSucceed && resultData.length >= 32) {
                                                  tokenDecimals = uint8(LibBytesV06.readUint256(resultData, 0));
                                              }
                                          }
                                          /// @dev Retrieves the allowance for a token, owner, and spender.
                                          ///      Returns `0` if the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param owner The owner of the tokens.
                                          /// @param spender The address the spender.
                                          /// @return allowance_ The allowance for a token, owner, and spender.
                                          function compatAllowance(
                                              IERC20Token token,
                                              address owner,
                                              address spender
                                          ) internal view returns (uint256 allowance_) {
                                              (bool didSucceed, bytes memory resultData) = address(token).staticcall(
                                                  abi.encodeWithSelector(token.allowance.selector, owner, spender)
                                              );
                                              if (didSucceed && resultData.length >= 32) {
                                                  allowance_ = LibBytesV06.readUint256(resultData, 0);
                                              }
                                          }
                                          /// @dev Retrieves the balance for a token owner.
                                          ///      Returns `0` if the call reverts.
                                          /// @param token The address of the token contract.
                                          /// @param owner The owner of the tokens.
                                          /// @return balance The token balance of an owner.
                                          function compatBalanceOf(IERC20Token token, address owner) internal view returns (uint256 balance) {
                                              (bool didSucceed, bytes memory resultData) = address(token).staticcall(
                                                  abi.encodeWithSelector(token.balanceOf.selector, owner)
                                              );
                                              if (didSucceed && resultData.length >= 32) {
                                                  balance = LibBytesV06.readUint256(resultData, 0);
                                              }
                                          }
                                          /// @dev Executes a call on address `target` with calldata `callData`
                                          ///      and asserts that either nothing was returned or a single boolean
                                          ///      was returned equal to `true`.
                                          /// @param target The call target.
                                          /// @param callData The abi-encoded call data.
                                          function _callWithOptionalBooleanResult(address target, bytes memory callData) private {
                                              (bool didSucceed, bytes memory resultData) = target.call(callData);
                                              // Revert if the call reverted.
                                              if (!didSucceed) {
                                                  LibRichErrorsV06.rrevert(resultData);
                                              }
                                              // If we get back 0 returndata, this may be a non-standard ERC-20 that
                                              // does not return a boolean. Check that it at least contains code.
                                              if (resultData.length == 0) {
                                                  uint256 size;
                                                  assembly {
                                                      size := extcodesize(target)
                                                  }
                                                  require(size > 0, "invalid token address, contains no code");
                                                  return;
                                              }
                                              // If we get back at least 32 bytes, we know the target address
                                              // contains code, and we assume it is a token that returned a boolean
                                              // success value, which must be true.
                                              if (resultData.length >= 32) {
                                                  uint256 result = LibBytesV06.readUint256(resultData, 0);
                                                  if (result == 1) {
                                                      return;
                                                  } else {
                                                      LibRichErrorsV06.rrevert(resultData);
                                                  }
                                              }
                                              // If 0 < returndatasize < 32, the target is a contract, but not a
                                              // valid token.
                                              LibRichErrorsV06.rrevert(resultData);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./errors/LibBytesRichErrorsV06.sol";
                                      import "./errors/LibRichErrorsV06.sol";
                                      library LibBytesV06 {
                                          using LibBytesV06 for bytes;
                                          /// @dev Gets the memory address for a byte array.
                                          /// @param input Byte array to lookup.
                                          /// @return memoryAddress Memory address of byte array. This
                                          ///         points to the header of the byte array which contains
                                          ///         the length.
                                          function rawAddress(bytes memory input) internal pure returns (uint256 memoryAddress) {
                                              assembly {
                                                  memoryAddress := input
                                              }
                                              return memoryAddress;
                                          }
                                          /// @dev Gets the memory address for the contents of a byte array.
                                          /// @param input Byte array to lookup.
                                          /// @return memoryAddress Memory address of the contents of the byte array.
                                          function contentAddress(bytes memory input) internal pure returns (uint256 memoryAddress) {
                                              assembly {
                                                  memoryAddress := add(input, 32)
                                              }
                                              return memoryAddress;
                                          }
                                          /// @dev Copies `length` bytes from memory location `source` to `dest`.
                                          /// @param dest memory address to copy bytes to.
                                          /// @param source memory address to copy bytes from.
                                          /// @param length number of bytes to copy.
                                          function memCopy(uint256 dest, uint256 source, uint256 length) internal pure {
                                              if (length < 32) {
                                                  // Handle a partial word by reading destination and masking
                                                  // off the bits we are interested in.
                                                  // This correctly handles overlap, zero lengths and source == dest
                                                  assembly {
                                                      let mask := sub(exp(256, sub(32, length)), 1)
                                                      let s := and(mload(source), not(mask))
                                                      let d := and(mload(dest), mask)
                                                      mstore(dest, or(s, d))
                                                  }
                                              } else {
                                                  // Skip the O(length) loop when source == dest.
                                                  if (source == dest) {
                                                      return;
                                                  }
                                                  // For large copies we copy whole words at a time. The final
                                                  // word is aligned to the end of the range (instead of after the
                                                  // previous) to handle partial words. So a copy will look like this:
                                                  //
                                                  //  ####
                                                  //      ####
                                                  //          ####
                                                  //            ####
                                                  //
                                                  // We handle overlap in the source and destination range by
                                                  // changing the copying direction. This prevents us from
                                                  // overwriting parts of source that we still need to copy.
                                                  //
                                                  // This correctly handles source == dest
                                                  //
                                                  if (source > dest) {
                                                      assembly {
                                                          // We subtract 32 from `sEnd` and `dEnd` because it
                                                          // is easier to compare with in the loop, and these
                                                          // are also the addresses we need for copying the
                                                          // last bytes.
                                                          length := sub(length, 32)
                                                          let sEnd := add(source, length)
                                                          let dEnd := add(dest, length)
                                                          // Remember the last 32 bytes of source
                                                          // This needs to be done here and not after the loop
                                                          // because we may have overwritten the last bytes in
                                                          // source already due to overlap.
                                                          let last := mload(sEnd)
                                                          // Copy whole words front to back
                                                          // Note: the first check is always true,
                                                          // this could have been a do-while loop.
                                                          for {
                                                          } lt(source, sEnd) {
                                                          } {
                                                              mstore(dest, mload(source))
                                                              source := add(source, 32)
                                                              dest := add(dest, 32)
                                                          }
                                                          // Write the last 32 bytes
                                                          mstore(dEnd, last)
                                                      }
                                                  } else {
                                                      assembly {
                                                          // We subtract 32 from `sEnd` and `dEnd` because those
                                                          // are the starting points when copying a word at the end.
                                                          length := sub(length, 32)
                                                          let sEnd := add(source, length)
                                                          let dEnd := add(dest, length)
                                                          // Remember the first 32 bytes of source
                                                          // This needs to be done here and not after the loop
                                                          // because we may have overwritten the first bytes in
                                                          // source already due to overlap.
                                                          let first := mload(source)
                                                          // Copy whole words back to front
                                                          // We use a signed comparisson here to allow dEnd to become
                                                          // negative (happens when source and dest < 32). Valid
                                                          // addresses in local memory will never be larger than
                                                          // 2**255, so they can be safely re-interpreted as signed.
                                                          // Note: the first check is always true,
                                                          // this could have been a do-while loop.
                                                          for {
                                                          } slt(dest, dEnd) {
                                                          } {
                                                              mstore(dEnd, mload(sEnd))
                                                              sEnd := sub(sEnd, 32)
                                                              dEnd := sub(dEnd, 32)
                                                          }
                                                          // Write the first 32 bytes
                                                          mstore(dest, first)
                                                      }
                                                  }
                                              }
                                          }
                                          /// @dev Returns a slices from a byte array.
                                          /// @param b The byte array to take a slice from.
                                          /// @param from The starting index for the slice (inclusive).
                                          /// @param to The final index for the slice (exclusive).
                                          /// @return result The slice containing bytes at indices [from, to)
                                          function slice(bytes memory b, uint256 from, uint256 to) internal pure returns (bytes memory result) {
                                              // Ensure that the from and to positions are valid positions for a slice within
                                              // the byte array that is being used.
                                              if (from > to) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.FromLessThanOrEqualsToRequired,
                                                          from,
                                                          to
                                                      )
                                                  );
                                              }
                                              if (to > b.length) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.ToLessThanOrEqualsLengthRequired,
                                                          to,
                                                          b.length
                                                      )
                                                  );
                                              }
                                              // Create a new bytes structure and copy contents
                                              result = new bytes(to - from);
                                              memCopy(result.contentAddress(), b.contentAddress() + from, result.length);
                                              return result;
                                          }
                                          /// @dev Returns a slice from a byte array without preserving the input.
                                          ///      When `from == 0`, the original array will match the slice.
                                          ///      In other cases its state will be corrupted.
                                          /// @param b The byte array to take a slice from. Will be destroyed in the process.
                                          /// @param from The starting index for the slice (inclusive).
                                          /// @param to The final index for the slice (exclusive).
                                          /// @return result The slice containing bytes at indices [from, to)
                                          function sliceDestructive(bytes memory b, uint256 from, uint256 to) internal pure returns (bytes memory result) {
                                              // Ensure that the from and to positions are valid positions for a slice within
                                              // the byte array that is being used.
                                              if (from > to) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.FromLessThanOrEqualsToRequired,
                                                          from,
                                                          to
                                                      )
                                                  );
                                              }
                                              if (to > b.length) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.ToLessThanOrEqualsLengthRequired,
                                                          to,
                                                          b.length
                                                      )
                                                  );
                                              }
                                              // Create a new bytes structure around [from, to) in-place.
                                              assembly {
                                                  result := add(b, from)
                                                  mstore(result, sub(to, from))
                                              }
                                              return result;
                                          }
                                          /// @dev Pops the last byte off of a byte array by modifying its length.
                                          /// @param b Byte array that will be modified.
                                          /// @return result The byte that was popped off.
                                          function popLastByte(bytes memory b) internal pure returns (bytes1 result) {
                                              if (b.length == 0) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanZeroRequired,
                                                          b.length,
                                                          0
                                                      )
                                                  );
                                              }
                                              // Store last byte.
                                              result = b[b.length - 1];
                                              assembly {
                                                  // Decrement length of byte array.
                                                  let newLen := sub(mload(b), 1)
                                                  mstore(b, newLen)
                                              }
                                              return result;
                                          }
                                          /// @dev Tests equality of two byte arrays.
                                          /// @param lhs First byte array to compare.
                                          /// @param rhs Second byte array to compare.
                                          /// @return equal True if arrays are the same. False otherwise.
                                          function equals(bytes memory lhs, bytes memory rhs) internal pure returns (bool equal) {
                                              // Keccak gas cost is 30 + numWords * 6. This is a cheap way to compare.
                                              // We early exit on unequal lengths, but keccak would also correctly
                                              // handle this.
                                              return lhs.length == rhs.length && keccak256(lhs) == keccak256(rhs);
                                          }
                                          /// @dev Reads an address from a position in a byte array.
                                          /// @param b Byte array containing an address.
                                          /// @param index Index in byte array of address.
                                          /// @return result address from byte array.
                                          function readAddress(bytes memory b, uint256 index) internal pure returns (address result) {
                                              if (b.length < index + 20) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsTwentyRequired,
                                                          b.length,
                                                          index + 20 // 20 is length of address
                                                      )
                                                  );
                                              }
                                              // Add offset to index:
                                              // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
                                              // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
                                              index += 20;
                                              // Read address from array memory
                                              assembly {
                                                  // 1. Add index to address of bytes array
                                                  // 2. Load 32-byte word from memory
                                                  // 3. Apply 20-byte mask to obtain address
                                                  result := and(mload(add(b, index)), 0xffffffffffffffffffffffffffffffffffffffff)
                                              }
                                              return result;
                                          }
                                          /// @dev Writes an address into a specific position in a byte array.
                                          /// @param b Byte array to insert address into.
                                          /// @param index Index in byte array of address.
                                          /// @param input Address to put into byte array.
                                          function writeAddress(bytes memory b, uint256 index, address input) internal pure {
                                              if (b.length < index + 20) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsTwentyRequired,
                                                          b.length,
                                                          index + 20 // 20 is length of address
                                                      )
                                                  );
                                              }
                                              // Add offset to index:
                                              // 1. Arrays are prefixed by 32-byte length parameter (add 32 to index)
                                              // 2. Account for size difference between address length and 32-byte storage word (subtract 12 from index)
                                              index += 20;
                                              // Store address into array memory
                                              assembly {
                                                  // The address occupies 20 bytes and mstore stores 32 bytes.
                                                  // First fetch the 32-byte word where we'll be storing the address, then
                                                  // apply a mask so we have only the bytes in the word that the address will not occupy.
                                                  // Then combine these bytes with the address and store the 32 bytes back to memory with mstore.
                                                  // 1. Add index to address of bytes array
                                                  // 2. Load 32-byte word from memory
                                                  // 3. Apply 12-byte mask to obtain extra bytes occupying word of memory where we'll store the address
                                                  let neighbors := and(
                                                      mload(add(b, index)),
                                                      0xffffffffffffffffffffffff0000000000000000000000000000000000000000
                                                  )
                                                  // Make sure input address is clean.
                                                  // (Solidity does not guarantee this)
                                                  input := and(input, 0xffffffffffffffffffffffffffffffffffffffff)
                                                  // Store the neighbors and address into memory
                                                  mstore(add(b, index), xor(input, neighbors))
                                              }
                                          }
                                          /// @dev Reads a bytes32 value from a position in a byte array.
                                          /// @param b Byte array containing a bytes32 value.
                                          /// @param index Index in byte array of bytes32 value.
                                          /// @return result bytes32 value from byte array.
                                          function readBytes32(bytes memory b, uint256 index) internal pure returns (bytes32 result) {
                                              if (b.length < index + 32) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsThirtyTwoRequired,
                                                          b.length,
                                                          index + 32
                                                      )
                                                  );
                                              }
                                              // Arrays are prefixed by a 256 bit length parameter
                                              index += 32;
                                              // Read the bytes32 from array memory
                                              assembly {
                                                  result := mload(add(b, index))
                                              }
                                              return result;
                                          }
                                          /// @dev Writes a bytes32 into a specific position in a byte array.
                                          /// @param b Byte array to insert <input> into.
                                          /// @param index Index in byte array of <input>.
                                          /// @param input bytes32 to put into byte array.
                                          function writeBytes32(bytes memory b, uint256 index, bytes32 input) internal pure {
                                              if (b.length < index + 32) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsThirtyTwoRequired,
                                                          b.length,
                                                          index + 32
                                                      )
                                                  );
                                              }
                                              // Arrays are prefixed by a 256 bit length parameter
                                              index += 32;
                                              // Read the bytes32 from array memory
                                              assembly {
                                                  mstore(add(b, index), input)
                                              }
                                          }
                                          /// @dev Reads a uint256 value from a position in a byte array.
                                          /// @param b Byte array containing a uint256 value.
                                          /// @param index Index in byte array of uint256 value.
                                          /// @return result uint256 value from byte array.
                                          function readUint256(bytes memory b, uint256 index) internal pure returns (uint256 result) {
                                              result = uint256(readBytes32(b, index));
                                              return result;
                                          }
                                          /// @dev Writes a uint256 into a specific position in a byte array.
                                          /// @param b Byte array to insert <input> into.
                                          /// @param index Index in byte array of <input>.
                                          /// @param input uint256 to put into byte array.
                                          function writeUint256(bytes memory b, uint256 index, uint256 input) internal pure {
                                              writeBytes32(b, index, bytes32(input));
                                          }
                                          /// @dev Reads an unpadded bytes4 value from a position in a byte array.
                                          /// @param b Byte array containing a bytes4 value.
                                          /// @param index Index in byte array of bytes4 value.
                                          /// @return result bytes4 value from byte array.
                                          function readBytes4(bytes memory b, uint256 index) internal pure returns (bytes4 result) {
                                              if (b.length < index + 4) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibBytesRichErrorsV06.InvalidByteOperationError(
                                                          LibBytesRichErrorsV06.InvalidByteOperationErrorCodes.LengthGreaterThanOrEqualsFourRequired,
                                                          b.length,
                                                          index + 4
                                                      )
                                                  );
                                              }
                                              // Arrays are prefixed by a 32 byte length field
                                              index += 32;
                                              // Read the bytes4 from array memory
                                              assembly {
                                                  result := mload(add(b, index))
                                                  // Solidity does not require us to clean the trailing bytes.
                                                  // We do it anyway
                                                  result := and(result, 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000)
                                              }
                                              return result;
                                          }
                                          /// @dev Writes a new length to a byte array.
                                          ///      Decreasing length will lead to removing the corresponding lower order bytes from the byte array.
                                          ///      Increasing length may lead to appending adjacent in-memory bytes to the end of the byte array.
                                          /// @param b Bytes array to write new length to.
                                          /// @param length New length of byte array.
                                          function writeLength(bytes memory b, uint256 length) internal pure {
                                              assembly {
                                                  mstore(b, length)
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibBytesRichErrorsV06 {
                                          enum InvalidByteOperationErrorCodes {
                                              FromLessThanOrEqualsToRequired,
                                              ToLessThanOrEqualsLengthRequired,
                                              LengthGreaterThanZeroRequired,
                                              LengthGreaterThanOrEqualsFourRequired,
                                              LengthGreaterThanOrEqualsTwentyRequired,
                                              LengthGreaterThanOrEqualsThirtyTwoRequired,
                                              LengthGreaterThanOrEqualsNestedBytesLengthRequired,
                                              DestinationLengthGreaterThanOrEqualSourceLengthRequired
                                          }
                                          // bytes4(keccak256("InvalidByteOperationError(uint8,uint256,uint256)"))
                                          bytes4 internal constant INVALID_BYTE_OPERATION_ERROR_SELECTOR = 0x28006595;
                                          function InvalidByteOperationError(
                                              InvalidByteOperationErrorCodes errorCode,
                                              uint256 offset,
                                              uint256 required
                                          ) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(INVALID_BYTE_OPERATION_ERROR_SELECTOR, errorCode, offset, required);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      /// @dev Helpers for moving tokens around.
                                      abstract contract FixinTokenSpender {
                                          // Mask of the lower 20 bytes of a bytes32.
                                          uint256 private constant ADDRESS_MASK = 0x000000000000000000000000ffffffffffffffffffffffffffffffffffffffff;
                                          /// @dev Transfers ERC20 tokens from `owner` to `to`.
                                          /// @param token The token to spend.
                                          /// @param owner The owner of the tokens.
                                          /// @param to The recipient of the tokens.
                                          /// @param amount The amount of `token` to transfer.
                                          function _transferERC20TokensFrom(IERC20Token token, address owner, address to, uint256 amount) internal {
                                              require(address(token) != address(this), "FixinTokenSpender/CANNOT_INVOKE_SELF");
                                              assembly {
                                                  let ptr := mload(0x40) // free memory pointer
                                                  // selector for transferFrom(address,address,uint256)
                                                  mstore(ptr, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
                                                  mstore(add(ptr, 0x04), and(owner, ADDRESS_MASK))
                                                  mstore(add(ptr, 0x24), and(to, ADDRESS_MASK))
                                                  mstore(add(ptr, 0x44), amount)
                                                  let success := call(gas(), and(token, ADDRESS_MASK), 0, ptr, 0x64, ptr, 32)
                                                  let rdsize := returndatasize()
                                                  // Check for ERC20 success. ERC20 tokens should return a boolean,
                                                  // but some don't. We accept 0-length return data as success, or at
                                                  // least 32 bytes that starts with a 32-byte boolean true.
                                                  success := and(
                                                      success, // call itself succeeded
                                                      or(
                                                          iszero(rdsize), // no return data, or
                                                          and(
                                                              iszero(lt(rdsize, 32)), // at least 32 bytes
                                                              eq(mload(ptr), 1) // starts with uint256(1)
                                                          )
                                                      )
                                                  )
                                                  if iszero(success) {
                                                      returndatacopy(ptr, 0, rdsize)
                                                      revert(ptr, rdsize)
                                                  }
                                              }
                                          }
                                          /// @dev Transfers ERC20 tokens from ourselves to `to`.
                                          /// @param token The token to spend.
                                          /// @param to The recipient of the tokens.
                                          /// @param amount The amount of `token` to transfer.
                                          function _transferERC20Tokens(IERC20Token token, address to, uint256 amount) internal {
                                              require(address(token) != address(this), "FixinTokenSpender/CANNOT_INVOKE_SELF");
                                              assembly {
                                                  let ptr := mload(0x40) // free memory pointer
                                                  // selector for transfer(address,uint256)
                                                  mstore(ptr, 0xa9059cbb00000000000000000000000000000000000000000000000000000000)
                                                  mstore(add(ptr, 0x04), and(to, ADDRESS_MASK))
                                                  mstore(add(ptr, 0x24), amount)
                                                  let success := call(gas(), and(token, ADDRESS_MASK), 0, ptr, 0x44, ptr, 32)
                                                  let rdsize := returndatasize()
                                                  // Check for ERC20 success. ERC20 tokens should return a boolean,
                                                  // but some don't. We accept 0-length return data as success, or at
                                                  // least 32 bytes that starts with a 32-byte boolean true.
                                                  success := and(
                                                      success, // call itself succeeded
                                                      or(
                                                          iszero(rdsize), // no return data, or
                                                          and(
                                                              iszero(lt(rdsize, 32)), // at least 32 bytes
                                                              eq(mload(ptr), 1) // starts with uint256(1)
                                                          )
                                                      )
                                                  )
                                                  if iszero(success) {
                                                      returndatacopy(ptr, 0, rdsize)
                                                      revert(ptr, rdsize)
                                                  }
                                              }
                                          }
                                          /// @dev Transfers some amount of ETH to the given recipient and
                                          ///      reverts if the transfer fails.
                                          /// @param recipient The recipient of the ETH.
                                          /// @param amount The amount of ETH to transfer.
                                          function _transferEth(address payable recipient, uint256 amount) internal {
                                              if (amount > 0) {
                                                  (bool success, ) = recipient.call{value: amount}("");
                                                  require(success, "FixinTokenSpender::_transferEth/TRANSFER_FAILED");
                                              }
                                          }
                                          /// @dev Gets the maximum amount of an ERC20 token `token` that can be
                                          ///      pulled from `owner` by this address.
                                          /// @param token The token to spend.
                                          /// @param owner The owner of the tokens.
                                          /// @return amount The amount of tokens that can be pulled.
                                          function _getSpendableERC20BalanceOf(IERC20Token token, address owner) internal view returns (uint256) {
                                              return LibSafeMathV06.min256(token.allowance(owner, address(this)), token.balanceOf(owner));
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../../fixins/FixinEIP712.sol";
                                      import "../interfaces/IMultiplexFeature.sol";
                                      import "../interfaces/IOtcOrdersFeature.sol";
                                      import "../libs/LibNativeOrder.sol";
                                      abstract contract MultiplexOtc is FixinEIP712 {
                                          using LibSafeMathV06 for uint256;
                                          event ExpiredOtcOrder(bytes32 orderHash, address maker, uint64 expiry);
                                          function _batchSellOtcOrder(
                                              IMultiplexFeature.BatchSellState memory state,
                                              IMultiplexFeature.BatchSellParams memory params,
                                              bytes memory wrappedCallData,
                                              uint256 sellAmount
                                          ) internal {
                                              // Decode the Otc order and signature.
                                              (LibNativeOrder.OtcOrder memory order, LibSignature.Signature memory signature) = abi.decode(
                                                  wrappedCallData,
                                                  (LibNativeOrder.OtcOrder, LibSignature.Signature)
                                              );
                                              // Validate tokens.
                                              require(
                                                  order.takerToken == params.inputToken && order.makerToken == params.outputToken,
                                                  "MultiplexOtc::_batchSellOtcOrder/OTC_ORDER_INVALID_TOKENS"
                                              );
                                              // Pre-emptively check if the order is expired.
                                              uint64 expiry = uint64(order.expiryAndNonce >> 192);
                                              if (expiry <= uint64(block.timestamp)) {
                                                  bytes32 orderHash = _getEIP712Hash(LibNativeOrder.getOtcOrderStructHash(order));
                                                  emit ExpiredOtcOrder(orderHash, order.maker, expiry);
                                                  return;
                                              }
                                              // Try filling the Otc order. Swallows reverts.
                                              try
                                                  IOtcOrdersFeature(address(this))._fillOtcOrder(
                                                      order,
                                                      signature,
                                                      sellAmount.safeDowncastToUint128(),
                                                      params.payer,
                                                      params.useSelfBalance,
                                                      params.recipient
                                                  )
                                              returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount) {
                                                  // Increment the sold and bought amounts.
                                                  state.soldAmount = state.soldAmount.safeAdd(takerTokenFilledAmount);
                                                  state.boughtAmount = state.boughtAmount.safeAdd(makerTokenFilledAmount);
                                              } catch {}
                                          }
                                          function _multiHopSellOtcOrder(
                                              IMultiplexFeature.MultiHopSellState memory state,
                                              IMultiplexFeature.MultiHopSellParams memory params,
                                              bytes memory wrappedCallData
                                          ) internal {
                                              // Decode the Otc order, and signature.
                                              (LibNativeOrder.OtcOrder memory order, LibSignature.Signature memory signature) = abi.decode(
                                                  wrappedCallData,
                                                  (LibNativeOrder.OtcOrder, LibSignature.Signature)
                                              );
                                              //Make sure that the otc orders maker and taker tokens match the fill sequence in params.tokens[]
                                              require(
                                                  address(order.takerToken) == params.tokens[state.hopIndex] &&
                                                      address(order.makerToken) == params.tokens[state.hopIndex + 1],
                                                  "MultiplexOtcOrder::_multiHopSellOtcOrder/INVALID_TOKENS"
                                              );
                                              // Try filling the Otc order. Bubble up reverts.
                                              (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount) = IOtcOrdersFeature(address(this))
                                                  ._fillOtcOrder(
                                                      order,
                                                      signature,
                                                      state.outputTokenAmount.safeDowncastToUint128(),
                                                      state.from,
                                                      params.useSelfBalance,
                                                      state.to
                                                  );
                                              //store the bought amount for the next hop
                                              state.outputTokenAmount = makerTokenFilledAmount;
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../libs/LibNativeOrder.sol";
                                      import "../libs/LibSignature.sol";
                                      /// @dev Feature for interacting with OTC orders.
                                      interface IOtcOrdersFeature {
                                          /// @dev Emitted whenever an `OtcOrder` is filled.
                                          /// @param orderHash The canonical hash of the order.
                                          /// @param maker The maker of the order.
                                          /// @param taker The taker of the order.
                                          /// @param makerTokenFilledAmount How much maker token was filled.
                                          /// @param takerTokenFilledAmount How much taker token was filled.
                                          event OtcOrderFilled(
                                              bytes32 orderHash,
                                              address maker,
                                              address taker,
                                              address makerToken,
                                              address takerToken,
                                              uint128 makerTokenFilledAmount,
                                              uint128 takerTokenFilledAmount
                                          );
                                          /// @dev Fill an OTC order for up to `takerTokenFillAmount` taker tokens.
                                          /// @param order The OTC order.
                                          /// @param makerSignature The order signature from the maker.
                                          /// @param takerTokenFillAmount Maximum taker token amount to fill this
                                          ///        order with.
                                          /// @return takerTokenFilledAmount How much taker token was filled.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function fillOtcOrder(
                                              LibNativeOrder.OtcOrder calldata order,
                                              LibSignature.Signature calldata makerSignature,
                                              uint128 takerTokenFillAmount
                                          ) external returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount);
                                          /// @dev Fill an OTC order for up to `takerTokenFillAmount` taker tokens.
                                          ///      Unwraps bought WETH into ETH before sending it to
                                          ///      the taker.
                                          /// @param order The OTC order.
                                          /// @param makerSignature The order signature from the maker.
                                          /// @param takerTokenFillAmount Maximum taker token amount to fill this
                                          ///        order with.
                                          /// @return takerTokenFilledAmount How much taker token was filled.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function fillOtcOrderForEth(
                                              LibNativeOrder.OtcOrder calldata order,
                                              LibSignature.Signature calldata makerSignature,
                                              uint128 takerTokenFillAmount
                                          ) external returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount);
                                          /// @dev Fill an OTC order whose taker token is WETH for up
                                          ///      to `msg.value`.
                                          /// @param order The OTC order.
                                          /// @param makerSignature The order signature from the maker.
                                          /// @return takerTokenFilledAmount How much taker token was filled.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function fillOtcOrderWithEth(
                                              LibNativeOrder.OtcOrder calldata order,
                                              LibSignature.Signature calldata makerSignature
                                          ) external payable returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount);
                                          /// @dev Fully fill an OTC order. "Meta-transaction" variant,
                                          ///      requires order to be signed by both maker and taker.
                                          /// @param order The OTC order.
                                          /// @param makerSignature The order signature from the maker.
                                          /// @param takerSignature The order signature from the taker.
                                          function fillTakerSignedOtcOrder(
                                              LibNativeOrder.OtcOrder calldata order,
                                              LibSignature.Signature calldata makerSignature,
                                              LibSignature.Signature calldata takerSignature
                                          ) external;
                                          /// @dev Fully fill an OTC order. "Meta-transaction" variant,
                                          ///      requires order to be signed by both maker and taker.
                                          ///      Unwraps bought WETH into ETH before sending it to
                                          ///      the taker.
                                          /// @param order The OTC order.
                                          /// @param makerSignature The order signature from the maker.
                                          /// @param takerSignature The order signature from the taker.
                                          function fillTakerSignedOtcOrderForEth(
                                              LibNativeOrder.OtcOrder calldata order,
                                              LibSignature.Signature calldata makerSignature,
                                              LibSignature.Signature calldata takerSignature
                                          ) external;
                                          /// @dev Fills multiple taker-signed OTC orders.
                                          /// @param orders Array of OTC orders.
                                          /// @param makerSignatures Array of maker signatures for each order.
                                          /// @param takerSignatures Array of taker signatures for each order.
                                          /// @param unwrapWeth Array of booleans representing whether or not
                                          ///        to unwrap bought WETH into ETH for each order. Should be set
                                          ///        to false if the maker token is not WETH.
                                          /// @return successes Array of booleans representing whether or not
                                          ///         each order in `orders` was filled successfully.
                                          function batchFillTakerSignedOtcOrders(
                                              LibNativeOrder.OtcOrder[] calldata orders,
                                              LibSignature.Signature[] calldata makerSignatures,
                                              LibSignature.Signature[] calldata takerSignatures,
                                              bool[] calldata unwrapWeth
                                          ) external returns (bool[] memory successes);
                                          /// @dev Fill an OTC order for up to `takerTokenFillAmount` taker tokens.
                                          ///      Internal variant.
                                          /// @param order The OTC order.
                                          /// @param makerSignature The order signature from the maker.
                                          /// @param takerTokenFillAmount Maximum taker token amount to fill this
                                          ///        order with.
                                          /// @param taker The address to fill the order in the context of.
                                          /// @param useSelfBalance Whether to use the Exchange Proxy's balance
                                          ///        of input tokens.
                                          /// @param recipient The recipient of the bought maker tokens.
                                          /// @return takerTokenFilledAmount How much taker token was filled.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function _fillOtcOrder(
                                              LibNativeOrder.OtcOrder calldata order,
                                              LibSignature.Signature calldata makerSignature,
                                              uint128 takerTokenFillAmount,
                                              address taker,
                                              bool useSelfBalance,
                                              address recipient
                                          ) external returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount);
                                          /// @dev Get the order info for an OTC order.
                                          /// @param order The OTC order.
                                          /// @return orderInfo Info about the order.
                                          function getOtcOrderInfo(
                                              LibNativeOrder.OtcOrder calldata order
                                          ) external view returns (LibNativeOrder.OtcOrderInfo memory orderInfo);
                                          /// @dev Get the canonical hash of an OTC order.
                                          /// @param order The OTC order.
                                          /// @return orderHash The order hash.
                                          function getOtcOrderHash(LibNativeOrder.OtcOrder calldata order) external view returns (bytes32 orderHash);
                                          /// @dev Get the last nonce used for a particular
                                          ///      tx.origin address and nonce bucket.
                                          /// @param txOrigin The address.
                                          /// @param nonceBucket The nonce bucket index.
                                          /// @return lastNonce The last nonce value used.
                                          function lastOtcTxOriginNonce(address txOrigin, uint64 nonceBucket) external view returns (uint128 lastNonce);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../../errors/LibNativeOrdersRichErrors.sol";
                                      /// @dev A library for common native order operations.
                                      library LibNativeOrder {
                                          using LibSafeMathV06 for uint256;
                                          using LibRichErrorsV06 for bytes;
                                          enum OrderStatus {
                                              INVALID,
                                              FILLABLE,
                                              FILLED,
                                              CANCELLED,
                                              EXPIRED
                                          }
                                          /// @dev A standard OTC or OO limit order.
                                          struct LimitOrder {
                                              IERC20Token makerToken;
                                              IERC20Token takerToken;
                                              uint128 makerAmount;
                                              uint128 takerAmount;
                                              uint128 takerTokenFeeAmount;
                                              address maker;
                                              address taker;
                                              address sender;
                                              address feeRecipient;
                                              bytes32 pool;
                                              uint64 expiry;
                                              uint256 salt;
                                          }
                                          /// @dev An RFQ limit order.
                                          struct RfqOrder {
                                              IERC20Token makerToken;
                                              IERC20Token takerToken;
                                              uint128 makerAmount;
                                              uint128 takerAmount;
                                              address maker;
                                              address taker;
                                              address txOrigin;
                                              bytes32 pool;
                                              uint64 expiry;
                                              uint256 salt;
                                          }
                                          /// @dev An OTC limit order.
                                          struct OtcOrder {
                                              IERC20Token makerToken;
                                              IERC20Token takerToken;
                                              uint128 makerAmount;
                                              uint128 takerAmount;
                                              address maker;
                                              address taker;
                                              address txOrigin;
                                              uint256 expiryAndNonce; // [uint64 expiry, uint64 nonceBucket, uint128 nonce]
                                          }
                                          /// @dev Info on a limit or RFQ order.
                                          struct OrderInfo {
                                              bytes32 orderHash;
                                              OrderStatus status;
                                              uint128 takerTokenFilledAmount;
                                          }
                                          /// @dev Info on an OTC order.
                                          struct OtcOrderInfo {
                                              bytes32 orderHash;
                                              OrderStatus status;
                                          }
                                          uint256 private constant UINT_128_MASK = (1 << 128) - 1;
                                          uint256 private constant UINT_64_MASK = (1 << 64) - 1;
                                          uint256 private constant ADDRESS_MASK = (1 << 160) - 1;
                                          // The type hash for limit orders, which is:
                                          // keccak256(abi.encodePacked(
                                          //     "LimitOrder(",
                                          //       "address makerToken,",
                                          //       "address takerToken,",
                                          //       "uint128 makerAmount,",
                                          //       "uint128 takerAmount,",
                                          //       "uint128 takerTokenFeeAmount,",
                                          //       "address maker,",
                                          //       "address taker,",
                                          //       "address sender,",
                                          //       "address feeRecipient,",
                                          //       "bytes32 pool,",
                                          //       "uint64 expiry,",
                                          //       "uint256 salt"
                                          //     ")"
                                          // ))
                                          uint256 private constant _LIMIT_ORDER_TYPEHASH = 0xce918627cb55462ddbb85e73de69a8b322f2bc88f4507c52fcad6d4c33c29d49;
                                          // The type hash for RFQ orders, which is:
                                          // keccak256(abi.encodePacked(
                                          //     "RfqOrder(",
                                          //       "address makerToken,",
                                          //       "address takerToken,",
                                          //       "uint128 makerAmount,",
                                          //       "uint128 takerAmount,",
                                          //       "address maker,",
                                          //       "address taker,",
                                          //       "address txOrigin,",
                                          //       "bytes32 pool,",
                                          //       "uint64 expiry,",
                                          //       "uint256 salt"
                                          //     ")"
                                          // ))
                                          uint256 private constant _RFQ_ORDER_TYPEHASH = 0xe593d3fdfa8b60e5e17a1b2204662ecbe15c23f2084b9ad5bae40359540a7da9;
                                          // The type hash for OTC orders, which is:
                                          // keccak256(abi.encodePacked(
                                          //     "OtcOrder(",
                                          //       "address makerToken,",
                                          //       "address takerToken,",
                                          //       "uint128 makerAmount,",
                                          //       "uint128 takerAmount,",
                                          //       "address maker,",
                                          //       "address taker,",
                                          //       "address txOrigin,",
                                          //       "uint256 expiryAndNonce"
                                          //     ")"
                                          // ))
                                          uint256 private constant _OTC_ORDER_TYPEHASH = 0x2f754524de756ae72459efbe1ec88c19a745639821de528ac3fb88f9e65e35c8;
                                          /// @dev Get the struct hash of a limit order.
                                          /// @param order The limit order.
                                          /// @return structHash The struct hash of the order.
                                          function getLimitOrderStructHash(LimitOrder memory order) internal pure returns (bytes32 structHash) {
                                              // The struct hash is:
                                              // keccak256(abi.encode(
                                              //   TYPE_HASH,
                                              //   order.makerToken,
                                              //   order.takerToken,
                                              //   order.makerAmount,
                                              //   order.takerAmount,
                                              //   order.takerTokenFeeAmount,
                                              //   order.maker,
                                              //   order.taker,
                                              //   order.sender,
                                              //   order.feeRecipient,
                                              //   order.pool,
                                              //   order.expiry,
                                              //   order.salt,
                                              // ))
                                              assembly {
                                                  let mem := mload(0x40)
                                                  mstore(mem, _LIMIT_ORDER_TYPEHASH)
                                                  // order.makerToken;
                                                  mstore(add(mem, 0x20), and(ADDRESS_MASK, mload(order)))
                                                  // order.takerToken;
                                                  mstore(add(mem, 0x40), and(ADDRESS_MASK, mload(add(order, 0x20))))
                                                  // order.makerAmount;
                                                  mstore(add(mem, 0x60), and(UINT_128_MASK, mload(add(order, 0x40))))
                                                  // order.takerAmount;
                                                  mstore(add(mem, 0x80), and(UINT_128_MASK, mload(add(order, 0x60))))
                                                  // order.takerTokenFeeAmount;
                                                  mstore(add(mem, 0xA0), and(UINT_128_MASK, mload(add(order, 0x80))))
                                                  // order.maker;
                                                  mstore(add(mem, 0xC0), and(ADDRESS_MASK, mload(add(order, 0xA0))))
                                                  // order.taker;
                                                  mstore(add(mem, 0xE0), and(ADDRESS_MASK, mload(add(order, 0xC0))))
                                                  // order.sender;
                                                  mstore(add(mem, 0x100), and(ADDRESS_MASK, mload(add(order, 0xE0))))
                                                  // order.feeRecipient;
                                                  mstore(add(mem, 0x120), and(ADDRESS_MASK, mload(add(order, 0x100))))
                                                  // order.pool;
                                                  mstore(add(mem, 0x140), mload(add(order, 0x120)))
                                                  // order.expiry;
                                                  mstore(add(mem, 0x160), and(UINT_64_MASK, mload(add(order, 0x140))))
                                                  // order.salt;
                                                  mstore(add(mem, 0x180), mload(add(order, 0x160)))
                                                  structHash := keccak256(mem, 0x1A0)
                                              }
                                          }
                                          /// @dev Get the struct hash of a RFQ order.
                                          /// @param order The RFQ order.
                                          /// @return structHash The struct hash of the order.
                                          function getRfqOrderStructHash(RfqOrder memory order) internal pure returns (bytes32 structHash) {
                                              // The struct hash is:
                                              // keccak256(abi.encode(
                                              //   TYPE_HASH,
                                              //   order.makerToken,
                                              //   order.takerToken,
                                              //   order.makerAmount,
                                              //   order.takerAmount,
                                              //   order.maker,
                                              //   order.taker,
                                              //   order.txOrigin,
                                              //   order.pool,
                                              //   order.expiry,
                                              //   order.salt,
                                              // ))
                                              assembly {
                                                  let mem := mload(0x40)
                                                  mstore(mem, _RFQ_ORDER_TYPEHASH)
                                                  // order.makerToken;
                                                  mstore(add(mem, 0x20), and(ADDRESS_MASK, mload(order)))
                                                  // order.takerToken;
                                                  mstore(add(mem, 0x40), and(ADDRESS_MASK, mload(add(order, 0x20))))
                                                  // order.makerAmount;
                                                  mstore(add(mem, 0x60), and(UINT_128_MASK, mload(add(order, 0x40))))
                                                  // order.takerAmount;
                                                  mstore(add(mem, 0x80), and(UINT_128_MASK, mload(add(order, 0x60))))
                                                  // order.maker;
                                                  mstore(add(mem, 0xA0), and(ADDRESS_MASK, mload(add(order, 0x80))))
                                                  // order.taker;
                                                  mstore(add(mem, 0xC0), and(ADDRESS_MASK, mload(add(order, 0xA0))))
                                                  // order.txOrigin;
                                                  mstore(add(mem, 0xE0), and(ADDRESS_MASK, mload(add(order, 0xC0))))
                                                  // order.pool;
                                                  mstore(add(mem, 0x100), mload(add(order, 0xE0)))
                                                  // order.expiry;
                                                  mstore(add(mem, 0x120), and(UINT_64_MASK, mload(add(order, 0x100))))
                                                  // order.salt;
                                                  mstore(add(mem, 0x140), mload(add(order, 0x120)))
                                                  structHash := keccak256(mem, 0x160)
                                              }
                                          }
                                          /// @dev Get the struct hash of an OTC order.
                                          /// @param order The OTC order.
                                          /// @return structHash The struct hash of the order.
                                          function getOtcOrderStructHash(OtcOrder memory order) internal pure returns (bytes32 structHash) {
                                              // The struct hash is:
                                              // keccak256(abi.encode(
                                              //   TYPE_HASH,
                                              //   order.makerToken,
                                              //   order.takerToken,
                                              //   order.makerAmount,
                                              //   order.takerAmount,
                                              //   order.maker,
                                              //   order.taker,
                                              //   order.txOrigin,
                                              //   order.expiryAndNonce,
                                              // ))
                                              assembly {
                                                  let mem := mload(0x40)
                                                  mstore(mem, _OTC_ORDER_TYPEHASH)
                                                  // order.makerToken;
                                                  mstore(add(mem, 0x20), and(ADDRESS_MASK, mload(order)))
                                                  // order.takerToken;
                                                  mstore(add(mem, 0x40), and(ADDRESS_MASK, mload(add(order, 0x20))))
                                                  // order.makerAmount;
                                                  mstore(add(mem, 0x60), and(UINT_128_MASK, mload(add(order, 0x40))))
                                                  // order.takerAmount;
                                                  mstore(add(mem, 0x80), and(UINT_128_MASK, mload(add(order, 0x60))))
                                                  // order.maker;
                                                  mstore(add(mem, 0xA0), and(ADDRESS_MASK, mload(add(order, 0x80))))
                                                  // order.taker;
                                                  mstore(add(mem, 0xC0), and(ADDRESS_MASK, mload(add(order, 0xA0))))
                                                  // order.txOrigin;
                                                  mstore(add(mem, 0xE0), and(ADDRESS_MASK, mload(add(order, 0xC0))))
                                                  // order.expiryAndNonce;
                                                  mstore(add(mem, 0x100), mload(add(order, 0xE0)))
                                                  structHash := keccak256(mem, 0x120)
                                              }
                                          }
                                          /// @dev Refund any leftover protocol fees in `msg.value` to `msg.sender`.
                                          /// @param ethProtocolFeePaid How much ETH was paid in protocol fees.
                                          function refundExcessProtocolFeeToSender(uint256 ethProtocolFeePaid) internal {
                                              if (msg.value > ethProtocolFeePaid && msg.sender != address(this)) {
                                                  uint256 refundAmount = msg.value.safeSub(ethProtocolFeePaid);
                                                  (bool success, ) = msg.sender.call{value: refundAmount}("");
                                                  if (!success) {
                                                      LibNativeOrdersRichErrors.ProtocolFeeRefundFailed(msg.sender, refundAmount).rrevert();
                                                  }
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibNativeOrdersRichErrors {
                                          function ProtocolFeeRefundFailed(address receiver, uint256 refundAmount) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("ProtocolFeeRefundFailed(address,uint256)")),
                                                      receiver,
                                                      refundAmount
                                                  );
                                          }
                                          function OrderNotFillableByOriginError(
                                              bytes32 orderHash,
                                              address txOrigin,
                                              address orderTxOrigin
                                          ) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("OrderNotFillableByOriginError(bytes32,address,address)")),
                                                      orderHash,
                                                      txOrigin,
                                                      orderTxOrigin
                                                  );
                                          }
                                          function OrderNotFillableError(bytes32 orderHash, uint8 orderStatus) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(bytes4(keccak256("OrderNotFillableError(bytes32,uint8)")), orderHash, orderStatus);
                                          }
                                          function OrderNotSignedByMakerError(
                                              bytes32 orderHash,
                                              address signer,
                                              address maker
                                          ) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("OrderNotSignedByMakerError(bytes32,address,address)")),
                                                      orderHash,
                                                      signer,
                                                      maker
                                                  );
                                          }
                                          function InvalidSignerError(address maker, address signer) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("InvalidSignerError(address,address)")), maker, signer);
                                          }
                                          function OrderNotFillableBySenderError(
                                              bytes32 orderHash,
                                              address sender,
                                              address orderSender
                                          ) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("OrderNotFillableBySenderError(bytes32,address,address)")),
                                                      orderHash,
                                                      sender,
                                                      orderSender
                                                  );
                                          }
                                          function OrderNotFillableByTakerError(
                                              bytes32 orderHash,
                                              address taker,
                                              address orderTaker
                                          ) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("OrderNotFillableByTakerError(bytes32,address,address)")),
                                                      orderHash,
                                                      taker,
                                                      orderTaker
                                                  );
                                          }
                                          function CancelSaltTooLowError(uint256 minValidSalt, uint256 oldMinValidSalt) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("CancelSaltTooLowError(uint256,uint256)")),
                                                      minValidSalt,
                                                      oldMinValidSalt
                                                  );
                                          }
                                          function FillOrKillFailedError(
                                              bytes32 orderHash,
                                              uint256 takerTokenFilledAmount,
                                              uint256 takerTokenFillAmount
                                          ) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("FillOrKillFailedError(bytes32,uint256,uint256)")),
                                                      orderHash,
                                                      takerTokenFilledAmount,
                                                      takerTokenFillAmount
                                                  );
                                          }
                                          function OnlyOrderMakerAllowed(
                                              bytes32 orderHash,
                                              address sender,
                                              address maker
                                          ) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("OnlyOrderMakerAllowed(bytes32,address,address)")),
                                                      orderHash,
                                                      sender,
                                                      maker
                                                  );
                                          }
                                          function BatchFillIncompleteError(
                                              bytes32 orderHash,
                                              uint256 takerTokenFilledAmount,
                                              uint256 takerTokenFillAmount
                                          ) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("BatchFillIncompleteError(bytes32,uint256,uint256)")),
                                                      orderHash,
                                                      takerTokenFilledAmount,
                                                      takerTokenFillAmount
                                                  );
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../../errors/LibSignatureRichErrors.sol";
                                      /// @dev A library for validating signatures.
                                      library LibSignature {
                                          using LibRichErrorsV06 for bytes;
                                          // '\\x19Ethereum Signed Message:\
                                      32\\x00\\x00\\x00\\x00' in a word.
                                          uint256 private constant ETH_SIGN_HASH_PREFIX = 0x19457468657265756d205369676e6564204d6573736167653a0a333200000000;
                                          /// @dev Exclusive upper limit on ECDSA signatures 'R' values.
                                          ///      The valid range is given by fig (282) of the yellow paper.
                                          uint256 private constant ECDSA_SIGNATURE_R_LIMIT =
                                              uint256(0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141);
                                          /// @dev Exclusive upper limit on ECDSA signatures 'S' values.
                                          ///      The valid range is given by fig (283) of the yellow paper.
                                          uint256 private constant ECDSA_SIGNATURE_S_LIMIT = ECDSA_SIGNATURE_R_LIMIT / 2 + 1;
                                          /// @dev Allowed signature types.
                                          enum SignatureType {
                                              ILLEGAL,
                                              INVALID,
                                              EIP712,
                                              ETHSIGN,
                                              PRESIGNED
                                          }
                                          /// @dev Encoded EC signature.
                                          struct Signature {
                                              // How to validate the signature.
                                              SignatureType signatureType;
                                              // EC Signature data.
                                              uint8 v;
                                              // EC Signature data.
                                              bytes32 r;
                                              // EC Signature data.
                                              bytes32 s;
                                          }
                                          /// @dev Retrieve the signer of a signature.
                                          ///      Throws if the signature can't be validated.
                                          /// @param hash The hash that was signed.
                                          /// @param signature The signature.
                                          /// @return recovered The recovered signer address.
                                          function getSignerOfHash(bytes32 hash, Signature memory signature) internal pure returns (address recovered) {
                                              // Ensure this is a signature type that can be validated against a hash.
                                              _validateHashCompatibleSignature(hash, signature);
                                              if (signature.signatureType == SignatureType.EIP712) {
                                                  // Signed using EIP712
                                                  recovered = ecrecover(hash, signature.v, signature.r, signature.s);
                                              } else if (signature.signatureType == SignatureType.ETHSIGN) {
                                                  // Signed using `eth_sign`
                                                  // Need to hash `hash` with "\\x19Ethereum Signed Message:\
                                      32" prefix
                                                  // in packed encoding.
                                                  bytes32 ethSignHash;
                                                  assembly {
                                                      // Use scratch space
                                                      mstore(0, ETH_SIGN_HASH_PREFIX) // length of 28 bytes
                                                      mstore(28, hash) // length of 32 bytes
                                                      ethSignHash := keccak256(0, 60)
                                                  }
                                                  recovered = ecrecover(ethSignHash, signature.v, signature.r, signature.s);
                                              }
                                              // `recovered` can be null if the signature values are out of range.
                                              if (recovered == address(0)) {
                                                  LibSignatureRichErrors
                                                      .SignatureValidationError(LibSignatureRichErrors.SignatureValidationErrorCodes.BAD_SIGNATURE_DATA, hash)
                                                      .rrevert();
                                              }
                                          }
                                          /// @dev Validates that a signature is compatible with a hash signee.
                                          /// @param hash The hash that was signed.
                                          /// @param signature The signature.
                                          function _validateHashCompatibleSignature(bytes32 hash, Signature memory signature) private pure {
                                              // Ensure the r and s are within malleability limits.
                                              if (uint256(signature.r) >= ECDSA_SIGNATURE_R_LIMIT || uint256(signature.s) >= ECDSA_SIGNATURE_S_LIMIT) {
                                                  LibSignatureRichErrors
                                                      .SignatureValidationError(LibSignatureRichErrors.SignatureValidationErrorCodes.BAD_SIGNATURE_DATA, hash)
                                                      .rrevert();
                                              }
                                              // Always illegal signature.
                                              if (signature.signatureType == SignatureType.ILLEGAL) {
                                                  LibSignatureRichErrors
                                                      .SignatureValidationError(LibSignatureRichErrors.SignatureValidationErrorCodes.ILLEGAL, hash)
                                                      .rrevert();
                                              }
                                              // Always invalid.
                                              if (signature.signatureType == SignatureType.INVALID) {
                                                  LibSignatureRichErrors
                                                      .SignatureValidationError(LibSignatureRichErrors.SignatureValidationErrorCodes.ALWAYS_INVALID, hash)
                                                      .rrevert();
                                              }
                                              // If a feature supports pre-signing, it wouldn't use
                                              // `getSignerOfHash` on a pre-signed order.
                                              if (signature.signatureType == SignatureType.PRESIGNED) {
                                                  LibSignatureRichErrors
                                                      .SignatureValidationError(LibSignatureRichErrors.SignatureValidationErrorCodes.UNSUPPORTED, hash)
                                                      .rrevert();
                                              }
                                              // Solidity should check that the signature type is within enum range for us
                                              // when abi-decoding.
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibSignatureRichErrors {
                                          enum SignatureValidationErrorCodes {
                                              ALWAYS_INVALID,
                                              INVALID_LENGTH,
                                              UNSUPPORTED,
                                              ILLEGAL,
                                              WRONG_SIGNER,
                                              BAD_SIGNATURE_DATA
                                          }
                                          function SignatureValidationError(
                                              SignatureValidationErrorCodes code,
                                              bytes32 hash,
                                              address signerAddress,
                                              bytes memory signature
                                          ) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("SignatureValidationError(uint8,bytes32,address,bytes)")),
                                                      code,
                                                      hash,
                                                      signerAddress,
                                                      signature
                                                  );
                                          }
                                          function SignatureValidationError(
                                              SignatureValidationErrorCodes code,
                                              bytes32 hash
                                          ) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("SignatureValidationError(uint8,bytes32)")), code, hash);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../../fixins/FixinEIP712.sol";
                                      import "../interfaces/IMultiplexFeature.sol";
                                      import "../interfaces/INativeOrdersFeature.sol";
                                      import "../libs/LibNativeOrder.sol";
                                      abstract contract MultiplexRfq is FixinEIP712 {
                                          using LibSafeMathV06 for uint256;
                                          event ExpiredRfqOrder(bytes32 orderHash, address maker, uint64 expiry);
                                          function _batchSellRfqOrder(
                                              IMultiplexFeature.BatchSellState memory state,
                                              IMultiplexFeature.BatchSellParams memory params,
                                              bytes memory wrappedCallData,
                                              uint256 sellAmount
                                          ) internal {
                                              // Decode the RFQ order and signature.
                                              (LibNativeOrder.RfqOrder memory order, LibSignature.Signature memory signature) = abi.decode(
                                                  wrappedCallData,
                                                  (LibNativeOrder.RfqOrder, LibSignature.Signature)
                                              );
                                              // Pre-emptively check if the order is expired.
                                              if (order.expiry <= uint64(block.timestamp)) {
                                                  bytes32 orderHash = _getEIP712Hash(LibNativeOrder.getRfqOrderStructHash(order));
                                                  emit ExpiredRfqOrder(orderHash, order.maker, order.expiry);
                                                  return;
                                              }
                                              // Validate tokens.
                                              require(
                                                  order.takerToken == params.inputToken && order.makerToken == params.outputToken,
                                                  "MultiplexRfq::_batchSellRfqOrder/RFQ_ORDER_INVALID_TOKENS"
                                              );
                                              // Try filling the RFQ order. Swallows reverts.
                                              try
                                                  INativeOrdersFeature(address(this))._fillRfqOrder(
                                                      order,
                                                      signature,
                                                      sellAmount.safeDowncastToUint128(),
                                                      params.payer,
                                                      params.useSelfBalance,
                                                      params.recipient
                                                  )
                                              returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount) {
                                                  // Increment the sold and bought amounts.
                                                  state.soldAmount = state.soldAmount.safeAdd(takerTokenFilledAmount);
                                                  state.boughtAmount = state.boughtAmount.safeAdd(makerTokenFilledAmount);
                                              } catch {}
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "../libs/LibSignature.sol";
                                      import "../libs/LibNativeOrder.sol";
                                      import "./INativeOrdersEvents.sol";
                                      /// @dev Feature for interacting with limit orders.
                                      interface INativeOrdersFeature is INativeOrdersEvents {
                                          /// @dev Transfers protocol fees from the `FeeCollector` pools into
                                          ///      the staking contract.
                                          /// @param poolIds Staking pool IDs
                                          function transferProtocolFeesForPools(bytes32[] calldata poolIds) external;
                                          /// @dev Fill a limit order. The taker and sender will be the caller.
                                          /// @param order The limit order. ETH protocol fees can be
                                          ///      attached to this call. Any unspent ETH will be refunded to
                                          ///      the caller.
                                          /// @param signature The order signature.
                                          /// @param takerTokenFillAmount Maximum taker token amount to fill this order with.
                                          /// @return takerTokenFilledAmount How much maker token was filled.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function fillLimitOrder(
                                              LibNativeOrder.LimitOrder calldata order,
                                              LibSignature.Signature calldata signature,
                                              uint128 takerTokenFillAmount
                                          ) external payable returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount);
                                          /// @dev Fill an RFQ order for up to `takerTokenFillAmount` taker tokens.
                                          ///      The taker will be the caller.
                                          /// @param order The RFQ order.
                                          /// @param signature The order signature.
                                          /// @param takerTokenFillAmount Maximum taker token amount to fill this order with.
                                          /// @return takerTokenFilledAmount How much maker token was filled.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function fillRfqOrder(
                                              LibNativeOrder.RfqOrder calldata order,
                                              LibSignature.Signature calldata signature,
                                              uint128 takerTokenFillAmount
                                          ) external returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount);
                                          /// @dev Fill an RFQ order for exactly `takerTokenFillAmount` taker tokens.
                                          ///      The taker will be the caller. ETH protocol fees can be
                                          ///      attached to this call. Any unspent ETH will be refunded to
                                          ///      the caller.
                                          /// @param order The limit order.
                                          /// @param signature The order signature.
                                          /// @param takerTokenFillAmount How much taker token to fill this order with.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function fillOrKillLimitOrder(
                                              LibNativeOrder.LimitOrder calldata order,
                                              LibSignature.Signature calldata signature,
                                              uint128 takerTokenFillAmount
                                          ) external payable returns (uint128 makerTokenFilledAmount);
                                          /// @dev Fill an RFQ order for exactly `takerTokenFillAmount` taker tokens.
                                          ///      The taker will be the caller.
                                          /// @param order The RFQ order.
                                          /// @param signature The order signature.
                                          /// @param takerTokenFillAmount How much taker token to fill this order with.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function fillOrKillRfqOrder(
                                              LibNativeOrder.RfqOrder calldata order,
                                              LibSignature.Signature calldata signature,
                                              uint128 takerTokenFillAmount
                                          ) external returns (uint128 makerTokenFilledAmount);
                                          /// @dev Fill a limit order. Internal variant. ETH protocol fees can be
                                          ///      attached to this call. Any unspent ETH will be refunded to
                                          ///      `msg.sender` (not `sender`).
                                          /// @param order The limit order.
                                          /// @param signature The order signature.
                                          /// @param takerTokenFillAmount Maximum taker token to fill this order with.
                                          /// @param taker The order taker.
                                          /// @param sender The order sender.
                                          /// @return takerTokenFilledAmount How much maker token was filled.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function _fillLimitOrder(
                                              LibNativeOrder.LimitOrder calldata order,
                                              LibSignature.Signature calldata signature,
                                              uint128 takerTokenFillAmount,
                                              address taker,
                                              address sender
                                          ) external payable returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount);
                                          /// @dev Fill an RFQ order. Internal variant.
                                          /// @param order The RFQ order.
                                          /// @param signature The order signature.
                                          /// @param takerTokenFillAmount Maximum taker token to fill this order with.
                                          /// @param taker The order taker.
                                          /// @param useSelfBalance Whether to use the ExchangeProxy's transient
                                          ///        balance of taker tokens to fill the order.
                                          /// @param recipient The recipient of the maker tokens.
                                          /// @return takerTokenFilledAmount How much maker token was filled.
                                          /// @return makerTokenFilledAmount How much maker token was filled.
                                          function _fillRfqOrder(
                                              LibNativeOrder.RfqOrder calldata order,
                                              LibSignature.Signature calldata signature,
                                              uint128 takerTokenFillAmount,
                                              address taker,
                                              bool useSelfBalance,
                                              address recipient
                                          ) external returns (uint128 takerTokenFilledAmount, uint128 makerTokenFilledAmount);
                                          /// @dev Cancel a single limit order. The caller must be the maker or a valid order signer.
                                          ///      Silently succeeds if the order has already been cancelled.
                                          /// @param order The limit order.
                                          function cancelLimitOrder(LibNativeOrder.LimitOrder calldata order) external;
                                          /// @dev Cancel a single RFQ order. The caller must be the maker or a valid order signer.
                                          ///      Silently succeeds if the order has already been cancelled.
                                          /// @param order The RFQ order.
                                          function cancelRfqOrder(LibNativeOrder.RfqOrder calldata order) external;
                                          /// @dev Mark what tx.origin addresses are allowed to fill an order that
                                          ///      specifies the message sender as its txOrigin.
                                          /// @param origins An array of origin addresses to update.
                                          /// @param allowed True to register, false to unregister.
                                          function registerAllowedRfqOrigins(address[] memory origins, bool allowed) external;
                                          /// @dev Cancel multiple limit orders. The caller must be the maker or a valid order signer.
                                          ///      Silently succeeds if the order has already been cancelled.
                                          /// @param orders The limit orders.
                                          function batchCancelLimitOrders(LibNativeOrder.LimitOrder[] calldata orders) external;
                                          /// @dev Cancel multiple RFQ orders. The caller must be the maker or a valid order signer.
                                          ///      Silently succeeds if the order has already been cancelled.
                                          /// @param orders The RFQ orders.
                                          function batchCancelRfqOrders(LibNativeOrder.RfqOrder[] calldata orders) external;
                                          /// @dev Cancel all limit orders for a given maker and pair with a salt less
                                          ///      than the value provided. The caller must be the maker. Subsequent
                                          ///      calls to this function with the same caller and pair require the
                                          ///      new salt to be >= the old salt.
                                          /// @param makerToken The maker token.
                                          /// @param takerToken The taker token.
                                          /// @param minValidSalt The new minimum valid salt.
                                          function cancelPairLimitOrders(IERC20Token makerToken, IERC20Token takerToken, uint256 minValidSalt) external;
                                          /// @dev Cancel all limit orders for a given maker and pair with a salt less
                                          ///      than the value provided. The caller must be a signer registered to the maker.
                                          ///      Subsequent calls to this function with the same maker and pair require the
                                          ///      new salt to be >= the old salt.
                                          /// @param maker The maker for which to cancel.
                                          /// @param makerToken The maker token.
                                          /// @param takerToken The taker token.
                                          /// @param minValidSalt The new minimum valid salt.
                                          function cancelPairLimitOrdersWithSigner(
                                              address maker,
                                              IERC20Token makerToken,
                                              IERC20Token takerToken,
                                              uint256 minValidSalt
                                          ) external;
                                          /// @dev Cancel all limit orders for a given maker and pairs with salts less
                                          ///      than the values provided. The caller must be the maker. Subsequent
                                          ///      calls to this function with the same caller and pair require the
                                          ///      new salt to be >= the old salt.
                                          /// @param makerTokens The maker tokens.
                                          /// @param takerTokens The taker tokens.
                                          /// @param minValidSalts The new minimum valid salts.
                                          function batchCancelPairLimitOrders(
                                              IERC20Token[] calldata makerTokens,
                                              IERC20Token[] calldata takerTokens,
                                              uint256[] calldata minValidSalts
                                          ) external;
                                          /// @dev Cancel all limit orders for a given maker and pairs with salts less
                                          ///      than the values provided. The caller must be a signer registered to the maker.
                                          ///      Subsequent calls to this function with the same maker and pair require the
                                          ///      new salt to be >= the old salt.
                                          /// @param maker The maker for which to cancel.
                                          /// @param makerTokens The maker tokens.
                                          /// @param takerTokens The taker tokens.
                                          /// @param minValidSalts The new minimum valid salts.
                                          function batchCancelPairLimitOrdersWithSigner(
                                              address maker,
                                              IERC20Token[] memory makerTokens,
                                              IERC20Token[] memory takerTokens,
                                              uint256[] memory minValidSalts
                                          ) external;
                                          /// @dev Cancel all RFQ orders for a given maker and pair with a salt less
                                          ///      than the value provided. The caller must be the maker. Subsequent
                                          ///      calls to this function with the same caller and pair require the
                                          ///      new salt to be >= the old salt.
                                          /// @param makerToken The maker token.
                                          /// @param takerToken The taker token.
                                          /// @param minValidSalt The new minimum valid salt.
                                          function cancelPairRfqOrders(IERC20Token makerToken, IERC20Token takerToken, uint256 minValidSalt) external;
                                          /// @dev Cancel all RFQ orders for a given maker and pair with a salt less
                                          ///      than the value provided. The caller must be a signer registered to the maker.
                                          ///      Subsequent calls to this function with the same maker and pair require the
                                          ///      new salt to be >= the old salt.
                                          /// @param maker The maker for which to cancel.
                                          /// @param makerToken The maker token.
                                          /// @param takerToken The taker token.
                                          /// @param minValidSalt The new minimum valid salt.
                                          function cancelPairRfqOrdersWithSigner(
                                              address maker,
                                              IERC20Token makerToken,
                                              IERC20Token takerToken,
                                              uint256 minValidSalt
                                          ) external;
                                          /// @dev Cancel all RFQ orders for a given maker and pairs with salts less
                                          ///      than the values provided. The caller must be the maker. Subsequent
                                          ///      calls to this function with the same caller and pair require the
                                          ///      new salt to be >= the old salt.
                                          /// @param makerTokens The maker tokens.
                                          /// @param takerTokens The taker tokens.
                                          /// @param minValidSalts The new minimum valid salts.
                                          function batchCancelPairRfqOrders(
                                              IERC20Token[] calldata makerTokens,
                                              IERC20Token[] calldata takerTokens,
                                              uint256[] calldata minValidSalts
                                          ) external;
                                          /// @dev Cancel all RFQ orders for a given maker and pairs with salts less
                                          ///      than the values provided. The caller must be a signer registered to the maker.
                                          ///      Subsequent calls to this function with the same maker and pair require the
                                          ///      new salt to be >= the old salt.
                                          /// @param maker The maker for which to cancel.
                                          /// @param makerTokens The maker tokens.
                                          /// @param takerTokens The taker tokens.
                                          /// @param minValidSalts The new minimum valid salts.
                                          function batchCancelPairRfqOrdersWithSigner(
                                              address maker,
                                              IERC20Token[] memory makerTokens,
                                              IERC20Token[] memory takerTokens,
                                              uint256[] memory minValidSalts
                                          ) external;
                                          /// @dev Get the order info for a limit order.
                                          /// @param order The limit order.
                                          /// @return orderInfo Info about the order.
                                          function getLimitOrderInfo(
                                              LibNativeOrder.LimitOrder calldata order
                                          ) external view returns (LibNativeOrder.OrderInfo memory orderInfo);
                                          /// @dev Get the order info for an RFQ order.
                                          /// @param order The RFQ order.
                                          /// @return orderInfo Info about the order.
                                          function getRfqOrderInfo(
                                              LibNativeOrder.RfqOrder calldata order
                                          ) external view returns (LibNativeOrder.OrderInfo memory orderInfo);
                                          /// @dev Get the canonical hash of a limit order.
                                          /// @param order The limit order.
                                          /// @return orderHash The order hash.
                                          function getLimitOrderHash(LibNativeOrder.LimitOrder calldata order) external view returns (bytes32 orderHash);
                                          /// @dev Get the canonical hash of an RFQ order.
                                          /// @param order The RFQ order.
                                          /// @return orderHash The order hash.
                                          function getRfqOrderHash(LibNativeOrder.RfqOrder calldata order) external view returns (bytes32 orderHash);
                                          /// @dev Get the protocol fee multiplier. This should be multiplied by the
                                          ///      gas price to arrive at the required protocol fee to fill a native order.
                                          /// @return multiplier The protocol fee multiplier.
                                          function getProtocolFeeMultiplier() external view returns (uint32 multiplier);
                                          /// @dev Get order info, fillable amount, and signature validity for a limit order.
                                          ///      Fillable amount is determined using balances and allowances of the maker.
                                          /// @param order The limit order.
                                          /// @param signature The order signature.
                                          /// @return orderInfo Info about the order.
                                          /// @return actualFillableTakerTokenAmount How much of the order is fillable
                                          ///         based on maker funds, in taker tokens.
                                          /// @return isSignatureValid Whether the signature is valid.
                                          function getLimitOrderRelevantState(
                                              LibNativeOrder.LimitOrder calldata order,
                                              LibSignature.Signature calldata signature
                                          )
                                              external
                                              view
                                              returns (
                                                  LibNativeOrder.OrderInfo memory orderInfo,
                                                  uint128 actualFillableTakerTokenAmount,
                                                  bool isSignatureValid
                                              );
                                          /// @dev Get order info, fillable amount, and signature validity for an RFQ order.
                                          ///      Fillable amount is determined using balances and allowances of the maker.
                                          /// @param order The RFQ order.
                                          /// @param signature The order signature.
                                          /// @return orderInfo Info about the order.
                                          /// @return actualFillableTakerTokenAmount How much of the order is fillable
                                          ///         based on maker funds, in taker tokens.
                                          /// @return isSignatureValid Whether the signature is valid.
                                          function getRfqOrderRelevantState(
                                              LibNativeOrder.RfqOrder calldata order,
                                              LibSignature.Signature calldata signature
                                          )
                                              external
                                              view
                                              returns (
                                                  LibNativeOrder.OrderInfo memory orderInfo,
                                                  uint128 actualFillableTakerTokenAmount,
                                                  bool isSignatureValid
                                              );
                                          /// @dev Batch version of `getLimitOrderRelevantState()`, without reverting.
                                          ///      Orders that would normally cause `getLimitOrderRelevantState()`
                                          ///      to revert will have empty results.
                                          /// @param orders The limit orders.
                                          /// @param signatures The order signatures.
                                          /// @return orderInfos Info about the orders.
                                          /// @return actualFillableTakerTokenAmounts How much of each order is fillable
                                          ///         based on maker funds, in taker tokens.
                                          /// @return isSignatureValids Whether each signature is valid for the order.
                                          function batchGetLimitOrderRelevantStates(
                                              LibNativeOrder.LimitOrder[] calldata orders,
                                              LibSignature.Signature[] calldata signatures
                                          )
                                              external
                                              view
                                              returns (
                                                  LibNativeOrder.OrderInfo[] memory orderInfos,
                                                  uint128[] memory actualFillableTakerTokenAmounts,
                                                  bool[] memory isSignatureValids
                                              );
                                          /// @dev Batch version of `getRfqOrderRelevantState()`, without reverting.
                                          ///      Orders that would normally cause `getRfqOrderRelevantState()`
                                          ///      to revert will have empty results.
                                          /// @param orders The RFQ orders.
                                          /// @param signatures The order signatures.
                                          /// @return orderInfos Info about the orders.
                                          /// @return actualFillableTakerTokenAmounts How much of each order is fillable
                                          ///         based on maker funds, in taker tokens.
                                          /// @return isSignatureValids Whether each signature is valid for the order.
                                          function batchGetRfqOrderRelevantStates(
                                              LibNativeOrder.RfqOrder[] calldata orders,
                                              LibSignature.Signature[] calldata signatures
                                          )
                                              external
                                              view
                                              returns (
                                                  LibNativeOrder.OrderInfo[] memory orderInfos,
                                                  uint128[] memory actualFillableTakerTokenAmounts,
                                                  bool[] memory isSignatureValids
                                              );
                                          /// @dev Register a signer who can sign on behalf of msg.sender
                                          ///      This allows one to sign on behalf of a contract that calls this function
                                          /// @param signer The address from which you plan to generate signatures
                                          /// @param allowed True to register, false to unregister.
                                          function registerAllowedOrderSigner(address signer, bool allowed) external;
                                          /// @dev checks if a given address is registered to sign on behalf of a maker address
                                          /// @param maker The maker address encoded in an order (can be a contract)
                                          /// @param signer The address that is providing a signature
                                          function isValidOrderSigner(address maker, address signer) external view returns (bool isAllowed);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "../libs/LibSignature.sol";
                                      import "../libs/LibNativeOrder.sol";
                                      /// @dev Events emitted by NativeOrdersFeature.
                                      interface INativeOrdersEvents {
                                          /// @dev Emitted whenever a `LimitOrder` is filled.
                                          /// @param orderHash The canonical hash of the order.
                                          /// @param maker The maker of the order.
                                          /// @param taker The taker of the order.
                                          /// @param feeRecipient Fee recipient of the order.
                                          /// @param takerTokenFilledAmount How much taker token was filled.
                                          /// @param makerTokenFilledAmount How much maker token was filled.
                                          /// @param protocolFeePaid How much protocol fee was paid.
                                          /// @param pool The fee pool associated with this order.
                                          event LimitOrderFilled(
                                              bytes32 orderHash,
                                              address maker,
                                              address taker,
                                              address feeRecipient,
                                              address makerToken,
                                              address takerToken,
                                              uint128 takerTokenFilledAmount,
                                              uint128 makerTokenFilledAmount,
                                              uint128 takerTokenFeeFilledAmount,
                                              uint256 protocolFeePaid,
                                              bytes32 pool
                                          );
                                          /// @dev Emitted whenever an `RfqOrder` is filled.
                                          /// @param orderHash The canonical hash of the order.
                                          /// @param maker The maker of the order.
                                          /// @param taker The taker of the order.
                                          /// @param takerTokenFilledAmount How much taker token was filled.
                                          /// @param makerTokenFilledAmount How much maker token was filled.
                                          /// @param pool The fee pool associated with this order.
                                          event RfqOrderFilled(
                                              bytes32 orderHash,
                                              address maker,
                                              address taker,
                                              address makerToken,
                                              address takerToken,
                                              uint128 takerTokenFilledAmount,
                                              uint128 makerTokenFilledAmount,
                                              bytes32 pool
                                          );
                                          /// @dev Emitted whenever a limit or RFQ order is cancelled.
                                          /// @param orderHash The canonical hash of the order.
                                          /// @param maker The order maker.
                                          event OrderCancelled(bytes32 orderHash, address maker);
                                          /// @dev Emitted whenever Limit orders are cancelled by pair by a maker.
                                          /// @param maker The maker of the order.
                                          /// @param makerToken The maker token in a pair for the orders cancelled.
                                          /// @param takerToken The taker token in a pair for the orders cancelled.
                                          /// @param minValidSalt The new minimum valid salt an order with this pair must
                                          ///        have.
                                          event PairCancelledLimitOrders(address maker, address makerToken, address takerToken, uint256 minValidSalt);
                                          /// @dev Emitted whenever RFQ orders are cancelled by pair by a maker.
                                          /// @param maker The maker of the order.
                                          /// @param makerToken The maker token in a pair for the orders cancelled.
                                          /// @param takerToken The taker token in a pair for the orders cancelled.
                                          /// @param minValidSalt The new minimum valid salt an order with this pair must
                                          ///        have.
                                          event PairCancelledRfqOrders(address maker, address makerToken, address takerToken, uint256 minValidSalt);
                                          /// @dev Emitted when new addresses are allowed or disallowed to fill
                                          ///      orders with a given txOrigin.
                                          /// @param origin The address doing the allowing.
                                          /// @param addrs The address being allowed/disallowed.
                                          /// @param allowed Indicates whether the address should be allowed.
                                          event RfqOrderOriginsAllowed(address origin, address[] addrs, bool allowed);
                                          /// @dev Emitted when new order signers are registered
                                          /// @param maker The maker address that is registering a designated signer.
                                          /// @param signer The address that will sign on behalf of maker.
                                          /// @param allowed Indicates whether the address should be allowed.
                                          event OrderSignerRegistered(address maker, address signer, bool allowed);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../interfaces/IMultiplexFeature.sol";
                                      import "../interfaces/ITransformERC20Feature.sol";
                                      abstract contract MultiplexTransformERC20 {
                                          using LibSafeMathV06 for uint256;
                                          function _batchSellTransformERC20(
                                              IMultiplexFeature.BatchSellState memory state,
                                              IMultiplexFeature.BatchSellParams memory params,
                                              bytes memory wrappedCallData,
                                              uint256 sellAmount
                                          ) internal {
                                              ITransformERC20Feature.TransformERC20Args memory args;
                                              // We want the TransformedERC20 event to have
                                              // `payer` as the taker.
                                              args.taker = payable(params.payer);
                                              args.inputToken = params.inputToken;
                                              args.outputToken = params.outputToken;
                                              args.inputTokenAmount = sellAmount;
                                              args.minOutputTokenAmount = 0;
                                              args.useSelfBalance = params.useSelfBalance;
                                              args.recipient = payable(params.recipient);
                                              (args.transformations) = abi.decode(wrappedCallData, (ITransformERC20Feature.Transformation[]));
                                              // Execute the transformations and swallow reverts.
                                              try ITransformERC20Feature(address(this))._transformERC20(args) returns (uint256 outputTokenAmount) {
                                                  // Increment the sold and bought amounts.
                                                  state.soldAmount = state.soldAmount.safeAdd(sellAmount);
                                                  state.boughtAmount = state.boughtAmount.safeAdd(outputTokenAmount);
                                              } catch {}
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "../../transformers/IERC20Transformer.sol";
                                      import "../../external/IFlashWallet.sol";
                                      /// @dev Feature to composably transform between ERC20 tokens.
                                      interface ITransformERC20Feature {
                                          /// @dev Defines a transformation to run in `transformERC20()`.
                                          struct Transformation {
                                              // The deployment nonce for the transformer.
                                              // The address of the transformer contract will be derived from this
                                              // value.
                                              uint32 deploymentNonce;
                                              // Arbitrary data to pass to the transformer.
                                              bytes data;
                                          }
                                          /// @dev Arguments for `_transformERC20()`.
                                          struct TransformERC20Args {
                                              // The taker address.
                                              address payable taker;
                                              // The token being provided by the taker.
                                              // If `0xeee...`, ETH is implied and should be provided with the call.`
                                              IERC20Token inputToken;
                                              // The token to be acquired by the taker.
                                              // `0xeee...` implies ETH.
                                              IERC20Token outputToken;
                                              // The amount of `inputToken` to take from the taker.
                                              // If set to `uint256(-1)`, the entire spendable balance of the taker
                                              // will be solt.
                                              uint256 inputTokenAmount;
                                              // The minimum amount of `outputToken` the taker
                                              // must receive for the entire transformation to succeed. If set to zero,
                                              // the minimum output token transfer will not be asserted.
                                              uint256 minOutputTokenAmount;
                                              // The transformations to execute on the token balance(s)
                                              // in sequence.
                                              Transformation[] transformations;
                                              // Whether to use the Exchange Proxy's balance of `inputToken`.
                                              bool useSelfBalance;
                                              // The recipient of the bought `outputToken`.
                                              address payable recipient;
                                          }
                                          /// @dev Raised upon a successful `transformERC20`.
                                          /// @param taker The taker (caller) address.
                                          /// @param inputToken The token being provided by the taker.
                                          ///        If `0xeee...`, ETH is implied and should be provided with the call.`
                                          /// @param outputToken The token to be acquired by the taker.
                                          ///        `0xeee...` implies ETH.
                                          /// @param inputTokenAmount The amount of `inputToken` to take from the taker.
                                          /// @param outputTokenAmount The amount of `outputToken` received by the taker.
                                          event TransformedERC20(
                                              address indexed taker,
                                              address inputToken,
                                              address outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 outputTokenAmount
                                          );
                                          /// @dev Raised when `setTransformerDeployer()` is called.
                                          /// @param transformerDeployer The new deployer address.
                                          event TransformerDeployerUpdated(address transformerDeployer);
                                          /// @dev Raised when `setQuoteSigner()` is called.
                                          /// @param quoteSigner The new quote signer.
                                          event QuoteSignerUpdated(address quoteSigner);
                                          /// @dev Replace the allowed deployer for transformers.
                                          ///      Only callable by the owner.
                                          /// @param transformerDeployer The address of the new trusted deployer
                                          ///        for transformers.
                                          function setTransformerDeployer(address transformerDeployer) external;
                                          /// @dev Replace the optional signer for `transformERC20()` calldata.
                                          ///      Only callable by the owner.
                                          /// @param quoteSigner The address of the new calldata signer.
                                          function setQuoteSigner(address quoteSigner) external;
                                          /// @dev Deploy a new flash wallet instance and replace the current one with it.
                                          ///      Useful if we somehow break the current wallet instance.
                                          ///       Only callable by the owner.
                                          /// @return wallet The new wallet instance.
                                          function createTransformWallet() external returns (IFlashWallet wallet);
                                          /// @dev Executes a series of transformations to convert an ERC20 `inputToken`
                                          ///      to an ERC20 `outputToken`.
                                          /// @param inputToken The token being provided by the sender.
                                          ///        If `0xeee...`, ETH is implied and should be provided with the call.`
                                          /// @param outputToken The token to be acquired by the sender.
                                          ///        `0xeee...` implies ETH.
                                          /// @param inputTokenAmount The amount of `inputToken` to take from the sender.
                                          /// @param minOutputTokenAmount The minimum amount of `outputToken` the sender
                                          ///        must receive for the entire transformation to succeed.
                                          /// @param transformations The transformations to execute on the token balance(s)
                                          ///        in sequence.
                                          /// @return outputTokenAmount The amount of `outputToken` received by the sender.
                                          function transformERC20(
                                              IERC20Token inputToken,
                                              IERC20Token outputToken,
                                              uint256 inputTokenAmount,
                                              uint256 minOutputTokenAmount,
                                              Transformation[] calldata transformations
                                          ) external payable returns (uint256 outputTokenAmount);
                                          /// @dev Internal version of `transformERC20()`. Only callable from within.
                                          /// @param args A `TransformERC20Args` struct.
                                          /// @return outputTokenAmount The amount of `outputToken` received by the taker.
                                          function _transformERC20(TransformERC20Args calldata args) external payable returns (uint256 outputTokenAmount);
                                          /// @dev Return the current wallet instance that will serve as the execution
                                          ///      context for transformations.
                                          /// @return wallet The wallet instance.
                                          function getTransformWallet() external view returns (IFlashWallet wallet);
                                          /// @dev Return the allowed deployer for transformers.
                                          /// @return deployer The transform deployer address.
                                          function getTransformerDeployer() external view returns (address deployer);
                                          /// @dev Return the optional signer for `transformERC20()` calldata.
                                          /// @return signer The transform deployer address.
                                          function getQuoteSigner() external view returns (address signer);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev A transformation callback used in `TransformERC20.transformERC20()`.
                                      interface IERC20Transformer {
                                          /// @dev Context information to pass into `transform()` by `TransformERC20.transformERC20()`.
                                          struct TransformContext {
                                              // The caller of `TransformERC20.transformERC20()`.
                                              address payable sender;
                                              // The recipient address, which may be distinct from `sender` e.g. in
                                              // meta-transactions.
                                              address payable recipient;
                                              // Arbitrary data to pass to the transformer.
                                              bytes data;
                                          }
                                          /// @dev Called from `TransformERC20.transformERC20()`. This will be
                                          ///      delegatecalled in the context of the FlashWallet instance being used.
                                          /// @param context Context information.
                                          /// @return success The success bytes (`LibERC20Transformer.TRANSFORMER_SUCCESS`).
                                          function transform(TransformContext calldata context) external returns (bytes4 success);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/interfaces/IOwnableV06.sol";
                                      /// @dev A contract that can execute arbitrary calls from its owner.
                                      interface IFlashWallet {
                                          /// @dev Execute an arbitrary call. Only an authority can call this.
                                          /// @param target The call target.
                                          /// @param callData The call data.
                                          /// @param value Ether to attach to the call.
                                          /// @return resultData The data returned by the call.
                                          function executeCall(
                                              address payable target,
                                              bytes calldata callData,
                                              uint256 value
                                          ) external payable returns (bytes memory resultData);
                                          /// @dev Execute an arbitrary delegatecall, in the context of this puppet.
                                          ///      Only an authority can call this.
                                          /// @param target The call target.
                                          /// @param callData The call data.
                                          /// @return resultData The data returned by the call.
                                          function executeDelegateCall(
                                              address payable target,
                                              bytes calldata callData
                                          ) external payable returns (bytes memory resultData);
                                          /// @dev Allows the puppet to receive ETH.
                                          receive() external payable;
                                          /// @dev Fetch the immutable owner/deployer of this contract.
                                          /// @return owner_ The immutable owner/deployer/
                                          function owner() external view returns (address owner_);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../../fixins/FixinCommon.sol";
                                      import "../../fixins/FixinTokenSpender.sol";
                                      import "../../vendor/IUniswapV2Pair.sol";
                                      import "../interfaces/IMultiplexFeature.sol";
                                      abstract contract MultiplexUniswapV2 is FixinCommon, FixinTokenSpender {
                                          using LibSafeMathV06 for uint256;
                                          // address of the UniswapV2Factory contract.
                                          address private immutable UNISWAP_FACTORY;
                                          // address of the (Sushiswap) UniswapV2Factory contract.
                                          address private immutable SUSHISWAP_FACTORY;
                                          // Init code hash of the UniswapV2Pair contract.
                                          bytes32 private immutable UNISWAP_PAIR_INIT_CODE_HASH;
                                          // Init code hash of the (Sushiswap) UniswapV2Pair contract.
                                          bytes32 private immutable SUSHISWAP_PAIR_INIT_CODE_HASH;
                                          constructor(
                                              address uniswapFactory,
                                              address sushiswapFactory,
                                              bytes32 uniswapPairInitCodeHash,
                                              bytes32 sushiswapPairInitCodeHash
                                          ) internal {
                                              UNISWAP_FACTORY = uniswapFactory;
                                              SUSHISWAP_FACTORY = sushiswapFactory;
                                              UNISWAP_PAIR_INIT_CODE_HASH = uniswapPairInitCodeHash;
                                              SUSHISWAP_PAIR_INIT_CODE_HASH = sushiswapPairInitCodeHash;
                                          }
                                          // A payable external function that we can delegatecall to
                                          // swallow reverts and roll back the input token transfer.
                                          function _batchSellUniswapV2External(
                                              IMultiplexFeature.BatchSellParams calldata params,
                                              bytes calldata wrappedCallData,
                                              uint256 sellAmount
                                          ) external payable returns (uint256 boughtAmount) {
                                              // Revert is not a delegatecall.
                                              require(
                                                  address(this) != _implementation,
                                                  "MultiplexLiquidityProvider::_batchSellUniswapV2External/ONLY_DELEGATECALL"
                                              );
                                              (address[] memory tokens, bool isSushi) = abi.decode(wrappedCallData, (address[], bool));
                                              // Validate tokens
                                              require(
                                                  tokens.length >= 2 &&
                                                      tokens[0] == address(params.inputToken) &&
                                                      tokens[tokens.length - 1] == address(params.outputToken),
                                                  "MultiplexUniswapV2::_batchSellUniswapV2/INVALID_TOKENS"
                                              );
                                              // Compute the address of the first Uniswap pair
                                              // contract that will execute a swap.
                                              address firstPairAddress = _computeUniswapPairAddress(tokens[0], tokens[1], isSushi);
                                              // `_sellToUniswapV2` assumes the input tokens have been
                                              // transferred into the pair contract before it is called,
                                              // so we transfer the tokens in now (either from `msg.sender`
                                              // or using the Exchange Proxy's balance).
                                              if (params.useSelfBalance) {
                                                  _transferERC20Tokens(IERC20Token(tokens[0]), firstPairAddress, sellAmount);
                                              } else {
                                                  _transferERC20TokensFrom(IERC20Token(tokens[0]), params.payer, firstPairAddress, sellAmount);
                                              }
                                              // Execute the Uniswap/Sushiswap trade.
                                              return _sellToUniswapV2(tokens, sellAmount, isSushi, firstPairAddress, params.recipient);
                                          }
                                          function _batchSellUniswapV2(
                                              IMultiplexFeature.BatchSellState memory state,
                                              IMultiplexFeature.BatchSellParams memory params,
                                              bytes memory wrappedCallData,
                                              uint256 sellAmount
                                          ) internal {
                                              // Swallow reverts
                                              (bool success, bytes memory resultData) = _implementation.delegatecall(
                                                  abi.encodeWithSelector(this._batchSellUniswapV2External.selector, params, wrappedCallData, sellAmount)
                                              );
                                              if (success) {
                                                  // Decode the output token amount on success.
                                                  uint256 boughtAmount = abi.decode(resultData, (uint256));
                                                  // Increment the sold and bought amounts.
                                                  state.soldAmount = state.soldAmount.safeAdd(sellAmount);
                                                  state.boughtAmount = state.boughtAmount.safeAdd(boughtAmount);
                                              }
                                          }
                                          function _multiHopSellUniswapV2(
                                              IMultiplexFeature.MultiHopSellState memory state,
                                              IMultiplexFeature.MultiHopSellParams memory params,
                                              bytes memory wrappedCallData
                                          ) internal {
                                              (address[] memory tokens, bool isSushi) = abi.decode(wrappedCallData, (address[], bool));
                                              // Validate the tokens
                                              require(
                                                  tokens.length >= 2 &&
                                                      tokens[0] == params.tokens[state.hopIndex] &&
                                                      tokens[tokens.length - 1] == params.tokens[state.hopIndex + 1],
                                                  "MultiplexUniswapV2::_multiHopSellUniswapV2/INVALID_TOKENS"
                                              );
                                              // Execute the Uniswap/Sushiswap trade.
                                              state.outputTokenAmount = _sellToUniswapV2(tokens, state.outputTokenAmount, isSushi, state.from, state.to);
                                          }
                                          function _sellToUniswapV2(
                                              address[] memory tokens,
                                              uint256 sellAmount,
                                              bool isSushi,
                                              address pairAddress,
                                              address recipient
                                          ) private returns (uint256 outputTokenAmount) {
                                              // Iterate through `tokens` perform a swap against the Uniswap
                                              // pair contract for each `(tokens[i], tokens[i+1])`.
                                              for (uint256 i = 0; i < tokens.length - 1; i++) {
                                                  (address inputToken, address outputToken) = (tokens[i], tokens[i + 1]);
                                                  // Compute the output token amount
                                                  outputTokenAmount = _computeUniswapOutputAmount(pairAddress, inputToken, outputToken, sellAmount);
                                                  (uint256 amount0Out, uint256 amount1Out) = inputToken < outputToken
                                                      ? (uint256(0), outputTokenAmount)
                                                      : (outputTokenAmount, uint256(0));
                                                  // The Uniswap pair contract will transfer the output tokens to
                                                  // the next pair contract if there is one, otherwise transfer to
                                                  // `recipient`.
                                                  address to = i < tokens.length - 2
                                                      ? _computeUniswapPairAddress(outputToken, tokens[i + 2], isSushi)
                                                      : recipient;
                                                  // Execute the swap.
                                                  IUniswapV2Pair(pairAddress).swap(amount0Out, amount1Out, to, new bytes(0));
                                                  // To avoid recomputing the pair address of the next pair, store
                                                  // `to` in `pairAddress`.
                                                  pairAddress = to;
                                                  // The outputTokenAmount
                                                  sellAmount = outputTokenAmount;
                                              }
                                          }
                                          // Computes the Uniswap/Sushiswap pair contract address for the
                                          // given tokens.
                                          function _computeUniswapPairAddress(
                                              address tokenA,
                                              address tokenB,
                                              bool isSushi
                                          ) internal view returns (address pairAddress) {
                                              // Tokens are lexicographically sorted in the Uniswap contract.
                                              (address token0, address token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
                                              if (isSushi) {
                                                  // Use the Sushiswap factory address and codehash
                                                  return
                                                      address(
                                                          uint256(
                                                              keccak256(
                                                                  abi.encodePacked(
                                                                      hex"ff",
                                                                      SUSHISWAP_FACTORY,
                                                                      keccak256(abi.encodePacked(token0, token1)),
                                                                      SUSHISWAP_PAIR_INIT_CODE_HASH
                                                                  )
                                                              )
                                                          )
                                                      );
                                              } else {
                                                  // Use the Uniswap factory address and codehash
                                                  return
                                                      address(
                                                          uint256(
                                                              keccak256(
                                                                  abi.encodePacked(
                                                                      hex"ff",
                                                                      UNISWAP_FACTORY,
                                                                      keccak256(abi.encodePacked(token0, token1)),
                                                                      UNISWAP_PAIR_INIT_CODE_HASH
                                                                  )
                                                              )
                                                          )
                                                      );
                                              }
                                          }
                                          // Computes the the amount of output token that would be bought
                                          // from Uniswap/Sushiswap given the input amount.
                                          function _computeUniswapOutputAmount(
                                              address pairAddress,
                                              address inputToken,
                                              address outputToken,
                                              uint256 inputAmount
                                          ) private view returns (uint256 outputAmount) {
                                              // Input amount should be non-zero.
                                              require(inputAmount > 0, "MultiplexUniswapV2::_computeUniswapOutputAmount/INSUFFICIENT_INPUT_AMOUNT");
                                              // Query the reserves of the pair contract.
                                              (uint256 reserve0, uint256 reserve1, ) = IUniswapV2Pair(pairAddress).getReserves();
                                              // Reserves must be non-zero.
                                              require(reserve0 > 0 && reserve1 > 0, "MultiplexUniswapV2::_computeUniswapOutputAmount/INSUFFICIENT_LIQUIDITY");
                                              // Tokens are lexicographically sorted in the Uniswap contract.
                                              (uint256 inputReserve, uint256 outputReserve) = inputToken < outputToken
                                                  ? (reserve0, reserve1)
                                                  : (reserve1, reserve0);
                                              // Compute the output amount.
                                              uint256 inputAmountWithFee = inputAmount.safeMul(997);
                                              uint256 numerator = inputAmountWithFee.safeMul(outputReserve);
                                              uint256 denominator = inputReserve.safeMul(1000).safeAdd(inputAmountWithFee);
                                              return numerator / denominator;
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.12;
                                      interface IUniswapV2Pair {
                                          event Swap(
                                              address indexed sender,
                                              uint256 amount0In,
                                              uint256 amount1In,
                                              uint256 amount0Out,
                                              uint256 amount1Out,
                                              address indexed to
                                          );
                                          function swap(uint256 amount0Out, uint256 amount1Out, address to, bytes calldata data) external;
                                          function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      import "../../fixins/FixinTokenSpender.sol";
                                      import "../interfaces/IMultiplexFeature.sol";
                                      import "../interfaces/IUniswapV3Feature.sol";
                                      abstract contract MultiplexUniswapV3 is FixinTokenSpender {
                                          using LibSafeMathV06 for uint256;
                                          function _batchSellUniswapV3(
                                              IMultiplexFeature.BatchSellState memory state,
                                              IMultiplexFeature.BatchSellParams memory params,
                                              bytes memory wrappedCallData,
                                              uint256 sellAmount
                                          ) internal {
                                              bool success;
                                              bytes memory resultData;
                                              if (params.useSelfBalance) {
                                                  // If the tokens are held by `address(this)`, we call
                                                  // the `onlySelf` variant `_sellHeldTokenForTokenToUniswapV3`,
                                                  // which uses the Exchange Proxy's balance of input token.
                                                  (success, resultData) = address(this).call(
                                                      abi.encodeWithSelector(
                                                          IUniswapV3Feature._sellHeldTokenForTokenToUniswapV3.selector,
                                                          wrappedCallData,
                                                          sellAmount,
                                                          0,
                                                          params.recipient
                                                      )
                                                  );
                                              } else {
                                                  // Otherwise, we self-call `_sellTokenForTokenToUniswapV3`,
                                                  // which pulls the input token from a specified `payer`.
                                                  (success, resultData) = address(this).call(
                                                      abi.encodeWithSelector(
                                                          IUniswapV3Feature._sellTokenForTokenToUniswapV3.selector,
                                                          wrappedCallData,
                                                          sellAmount,
                                                          0,
                                                          params.recipient,
                                                          params.payer
                                                      )
                                                  );
                                              }
                                              if (success) {
                                                  // Decode the output token amount on success.
                                                  uint256 outputTokenAmount = abi.decode(resultData, (uint256));
                                                  // Increment the sold and bought amounts.
                                                  state.soldAmount = state.soldAmount.safeAdd(sellAmount);
                                                  state.boughtAmount = state.boughtAmount.safeAdd(outputTokenAmount);
                                              }
                                          }
                                          function _multiHopSellUniswapV3(
                                              IMultiplexFeature.MultiHopSellState memory state,
                                              IMultiplexFeature.MultiHopSellParams memory params,
                                              bytes memory wrappedCallData
                                          ) internal {
                                              bool success;
                                              bytes memory resultData;
                                              if (state.from == address(this)) {
                                                  // If the tokens are held by `address(this)`, we call
                                                  // the `onlySelf` variant `_sellHeldTokenForTokenToUniswapV3`,
                                                  // which uses the Exchange Proxy's balance of input token.
                                                  (success, resultData) = address(this).call(
                                                      abi.encodeWithSelector(
                                                          IUniswapV3Feature._sellHeldTokenForTokenToUniswapV3.selector,
                                                          wrappedCallData,
                                                          state.outputTokenAmount,
                                                          0,
                                                          state.to
                                                      )
                                                  );
                                              } else {
                                                  // Otherwise, we self-call `_sellTokenForTokenToUniswapV3`,
                                                  // which pulls the input token from `payer`.
                                                  (success, resultData) = address(this).call(
                                                      abi.encodeWithSelector(
                                                          IUniswapV3Feature._sellTokenForTokenToUniswapV3.selector,
                                                          wrappedCallData,
                                                          state.outputTokenAmount,
                                                          0,
                                                          state.to,
                                                          params.payer
                                                      )
                                                  );
                                              }
                                              if (success) {
                                                  // Decode the output token amount on success.
                                                  state.outputTokenAmount = abi.decode(resultData, (uint256));
                                              } else {
                                                  revert("MultiplexUniswapV3::_multiHopSellUniswapV3/SWAP_FAILED");
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev VIP uniswap v3 fill functions.
                                      interface IUniswapV3Feature {
                                          /// @dev Sell attached ETH directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path, where the first token is WETH.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function sellEthForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) external payable returns (uint256 buyAmount);
                                          /// @dev Sell a token for ETH directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path, where the last token is WETH.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of ETH to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of ETH bought.
                                          function sellTokenForEthToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address payable recipient
                                          ) external returns (uint256 buyAmount);
                                          /// @dev Sell a token for another token directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function sellTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) external returns (uint256 buyAmount);
                                          /// @dev Sell a token for another token directly against uniswap v3. Internal variant.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for payer.
                                          /// @param payer The address to pull the sold tokens from.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function _sellTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient,
                                              address payer
                                          ) external returns (uint256 buyAmount);
                                          /// @dev Sell a token for another token directly against uniswap v3.
                                          ///      Private variant, uses tokens held by `address(this)`.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function _sellHeldTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) external returns (uint256 buyAmount);
                                          /// @dev The UniswapV3 pool swap callback which pays the funds requested
                                          ///      by the caller/pool to the pool. Can only be called by a valid
                                          ///      UniswapV3 pool.
                                          /// @param amount0Delta Token0 amount owed.
                                          /// @param amount1Delta Token1 amount owed.
                                          /// @param data Arbitrary data forwarded from swap() caller. An ABI-encoded
                                          ///        struct of: inputToken, outputToken, fee, payer
                                          function uniswapV3SwapCallback(int256 amount0Delta, int256 amount1Delta, bytes calldata data) external;
                                      }
                                      

                                      File 10 of 11: RenderToken
                                      pragma solidity ^0.4.24;
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/node_modules/openzeppelin-zos/contracts/token/ERC20/ERC20Basic.sol
                                      
                                      /**
                                       * @title ERC20Basic
                                       * @dev Simpler version of ERC20 interface
                                       * @dev see https://github.com/ethereum/EIPs/issues/179
                                       */
                                      contract ERC20Basic {
                                        function totalSupply() public view returns (uint256);
                                        function balanceOf(address who) public view returns (uint256);
                                        function transfer(address to, uint256 value) public returns (bool);
                                        event Transfer(address indexed from, address indexed to, uint256 value);
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/node_modules/openzeppelin-zos/contracts/token/ERC20/ERC20.sol
                                      
                                      /**
                                       * @title ERC20 interface
                                       * @dev see https://github.com/ethereum/EIPs/issues/20
                                       */
                                      contract ERC20 is ERC20Basic {
                                        function allowance(address owner, address spender) public view returns (uint256);
                                        function transferFrom(address from, address to, uint256 value) public returns (bool);
                                        function approve(address spender, uint256 value) public returns (bool);
                                        event Approval(address indexed owner, address indexed spender, uint256 value);
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/node_modules/openzeppelin-zos/contracts/token/ERC20/SafeERC20.sol
                                      
                                      /**
                                       * @title SafeERC20
                                       * @dev Wrappers around ERC20 operations that throw on failure.
                                       * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
                                       * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
                                       */
                                      library SafeERC20 {
                                        function safeTransfer(ERC20Basic token, address to, uint256 value) internal {
                                          assert(token.transfer(to, value));
                                        }
                                      
                                        function safeTransferFrom(
                                          ERC20 token,
                                          address from,
                                          address to,
                                          uint256 value
                                        )
                                          internal
                                        {
                                          assert(token.transferFrom(from, to, value));
                                        }
                                      
                                        function safeApprove(ERC20 token, address spender, uint256 value) internal {
                                          assert(token.approve(spender, value));
                                        }
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/node_modules/zos-lib/contracts/migrations/Migratable.sol
                                      
                                      /**
                                       * @title Migratable
                                       * Helper contract to support intialization and migration schemes between
                                       * different implementations of a contract in the context of upgradeability.
                                       * To use it, replace the constructor with a function that has the
                                       * `isInitializer` modifier starting with `"0"` as `migrationId`.
                                       * When you want to apply some migration code during an upgrade, increase
                                       * the `migrationId`. Or, if the migration code must be applied only after
                                       * another migration has been already applied, use the `isMigration` modifier.
                                       * This helper supports multiple inheritance.
                                       * WARNING: It is the developer's responsibility to ensure that migrations are
                                       * applied in a correct order, or that they are run at all.
                                       * See `Initializable` for a simpler version.
                                       */
                                      contract Migratable {
                                        /**
                                         * @dev Emitted when the contract applies a migration.
                                         * @param contractName Name of the Contract.
                                         * @param migrationId Identifier of the migration applied.
                                         */
                                        event Migrated(string contractName, string migrationId);
                                      
                                        /**
                                         * @dev Mapping of the already applied migrations.
                                         * (contractName => (migrationId => bool))
                                         */
                                        mapping (string => mapping (string => bool)) internal migrated;
                                      
                                        /**
                                         * @dev Internal migration id used to specify that a contract has already been initialized.
                                         */
                                        string constant private INITIALIZED_ID = "initialized";
                                      
                                      
                                        /**
                                         * @dev Modifier to use in the initialization function of a contract.
                                         * @param contractName Name of the contract.
                                         * @param migrationId Identifier of the migration.
                                         */
                                        modifier isInitializer(string contractName, string migrationId) {
                                          validateMigrationIsPending(contractName, INITIALIZED_ID);
                                          validateMigrationIsPending(contractName, migrationId);
                                          _;
                                          emit Migrated(contractName, migrationId);
                                          migrated[contractName][migrationId] = true;
                                          migrated[contractName][INITIALIZED_ID] = true;
                                        }
                                      
                                        /**
                                         * @dev Modifier to use in the migration of a contract.
                                         * @param contractName Name of the contract.
                                         * @param requiredMigrationId Identifier of the previous migration, required
                                         * to apply new one.
                                         * @param newMigrationId Identifier of the new migration to be applied.
                                         */
                                        modifier isMigration(string contractName, string requiredMigrationId, string newMigrationId) {
                                          require(isMigrated(contractName, requiredMigrationId), "Prerequisite migration ID has not been run yet");
                                          validateMigrationIsPending(contractName, newMigrationId);
                                          _;
                                          emit Migrated(contractName, newMigrationId);
                                          migrated[contractName][newMigrationId] = true;
                                        }
                                      
                                        /**
                                         * @dev Returns true if the contract migration was applied.
                                         * @param contractName Name of the contract.
                                         * @param migrationId Identifier of the migration.
                                         * @return true if the contract migration was applied, false otherwise.
                                         */
                                        function isMigrated(string contractName, string migrationId) public view returns(bool) {
                                          return migrated[contractName][migrationId];
                                        }
                                      
                                        /**
                                         * @dev Initializer that marks the contract as initialized.
                                         * It is important to run this if you had deployed a previous version of a Migratable contract.
                                         * For more information see https://github.com/zeppelinos/zos-lib/issues/158.
                                         */
                                        function initialize() isInitializer("Migratable", "1.2.1") public {
                                        }
                                      
                                        /**
                                         * @dev Reverts if the requested migration was already executed.
                                         * @param contractName Name of the contract.
                                         * @param migrationId Identifier of the migration.
                                         */
                                        function validateMigrationIsPending(string contractName, string migrationId) private {
                                          require(!isMigrated(contractName, migrationId), "Requested target migration ID has already been run");
                                        }
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/node_modules/openzeppelin-zos/contracts/ownership/Ownable.sol
                                      
                                      /**
                                       * @title Ownable
                                       * @dev The Ownable contract has an owner address, and provides basic authorization control
                                       * functions, this simplifies the implementation of "user permissions".
                                       */
                                      contract Ownable is Migratable {
                                        address public owner;
                                      
                                      
                                        event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
                                      
                                        /**
                                         * @dev The Ownable constructor sets the original `owner` of the contract to the sender
                                         * account.
                                         */
                                        function initialize(address _sender) public isInitializer("Ownable", "1.9.0") {
                                          owner = _sender;
                                        }
                                      
                                        /**
                                         * @dev Throws if called by any account other than the owner.
                                         */
                                        modifier onlyOwner() {
                                          require(msg.sender == owner);
                                          _;
                                        }
                                      
                                        /**
                                         * @dev Allows the current owner to transfer control of the contract to a newOwner.
                                         * @param newOwner The address to transfer ownership to.
                                         */
                                        function transferOwnership(address newOwner) public onlyOwner {
                                          require(newOwner != address(0));
                                          emit OwnershipTransferred(owner, newOwner);
                                          owner = newOwner;
                                        }
                                      
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/node_modules/openzeppelin-zos/contracts/math/SafeMath.sol
                                      
                                      /**
                                       * @title SafeMath
                                       * @dev Math operations with safety checks that throw on error
                                       */
                                      library SafeMath {
                                      
                                        /**
                                        * @dev Multiplies two numbers, throws on overflow.
                                        */
                                        function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
                                          if (a == 0) {
                                            return 0;
                                          }
                                          c = a * b;
                                          assert(c / a == b);
                                          return c;
                                        }
                                      
                                        /**
                                        * @dev Integer division of two numbers, truncating the quotient.
                                        */
                                        function div(uint256 a, uint256 b) internal pure returns (uint256) {
                                          // assert(b > 0); // Solidity automatically throws when dividing by 0
                                          // uint256 c = a / b;
                                          // assert(a == b * c + a % b); // There is no case in which this doesn't hold
                                          return a / b;
                                        }
                                      
                                        /**
                                        * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
                                        */
                                        function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                                          assert(b <= a);
                                          return a - b;
                                        }
                                      
                                        /**
                                        * @dev Adds two numbers, throws on overflow.
                                        */
                                        function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
                                          c = a + b;
                                          assert(c >= a);
                                          return c;
                                        }
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/contracts/Escrow.sol
                                      
                                      /**
                                       * @title Escrow
                                       * @dev Escrow contract that works with RNDR token
                                       * This contract holds tokens while render jobs are being completed
                                       * and information on token allottment per job
                                       */
                                      contract Escrow is Migratable, Ownable {
                                        using SafeERC20 for ERC20;
                                        using SafeMath for uint256;
                                      
                                        // This is a mapping of job IDs to the number of tokens allotted to the job
                                        mapping(string => uint256) private jobBalances;
                                        // This is the address of the render token contract
                                        address public renderTokenAddress;
                                        // This is the address with authority to call the disburseJob function
                                        address public disbursalAddress;
                                      
                                        // Emit new disbursal address when disbursalAddress has been changed
                                        event DisbursalAddressUpdate(address disbursalAddress);
                                        // Emit the jobId along with the new balance of the job
                                        // Used on job creation, additional funding added to jobs, and job disbursal
                                        // Internal systems for assigning jobs will watch this event to determine balances available
                                        event JobBalanceUpdate(string _jobId, uint256 _balance);
                                        // Emit new contract address when renderTokenAddress has been changed
                                        event RenderTokenAddressUpdate(address renderTokenAddress);
                                      
                                        /**
                                         * @dev Modifier to check if the message sender can call the disburseJob function
                                         */
                                        modifier canDisburse() {
                                          require(msg.sender == disbursalAddress, "message sender not authorized to disburse funds");
                                          _;
                                        }
                                      
                                        /**
                                         * @dev Initailization
                                         * @param _owner because this contract uses proxies, owner must be passed in as a param
                                         * @param _renderTokenAddress see renderTokenAddress
                                         */
                                        function initialize (address _owner, address _renderTokenAddress) public isInitializer("Escrow", "0") {
                                          require(_owner != address(0), "_owner must not be null");
                                          require(_renderTokenAddress != address(0), "_renderTokenAddress must not be null");
                                          Ownable.initialize(_owner);
                                          disbursalAddress = _owner;
                                          renderTokenAddress = _renderTokenAddress;
                                        }
                                      
                                        /**
                                         * @dev Change the address authorized to distribute tokens for completed jobs
                                         *
                                         * Because there are no on-chain details to indicate who performed a render, an outside
                                         * system must call the disburseJob function with the information needed to properly
                                         * distribute tokens. This function updates the address with the authority to perform distributions
                                         * @param _newDisbursalAddress see disbursalAddress
                                         */
                                        function changeDisbursalAddress(address _newDisbursalAddress) external onlyOwner {
                                          disbursalAddress = _newDisbursalAddress;
                                      
                                          emit DisbursalAddressUpdate(disbursalAddress);
                                        }
                                      
                                        /**
                                         * @dev Change the address allowances will be sent to after job completion
                                         *
                                         * Ideally, this will not be used, but is included as a failsafe.
                                         * RNDR is still in its infancy, and changes may need to be made to this
                                         * contract and / or the renderToken contract. Including methods to update the
                                         * addresses allows the contracts to update independently.
                                         * If the RNDR token contract is ever migrated to another address for
                                         * either added security or functionality, this will need to be called.
                                         * @param _newRenderTokenAddress see renderTokenAddress
                                         */
                                        function changeRenderTokenAddress(address _newRenderTokenAddress) external onlyOwner {
                                          require(_newRenderTokenAddress != address(0), "_newRenderTokenAddress must not be null");
                                          renderTokenAddress = _newRenderTokenAddress;
                                      
                                          emit RenderTokenAddressUpdate(renderTokenAddress);
                                        }
                                      
                                        /**
                                         * @dev Send allowances to node(s) that performed a job
                                         *
                                         * This can only be called by the disbursalAddress, an accound owned
                                         * by OTOY, and it provides the number of tokens to send to each node
                                         * @param _jobId the ID of the job used in the jobBalances mapping
                                         * @param _recipients the address(es) of the nodes that performed rendering
                                         * @param _amounts the amount(s) to send to each address. These must be in the same
                                         * order as the recipient addresses
                                         */
                                        function disburseJob(string _jobId, address[] _recipients, uint256[] _amounts) external canDisburse {
                                          require(jobBalances[_jobId] > 0, "_jobId has no available balance");
                                          require(_recipients.length == _amounts.length, "_recipients and _amounts must be the same length");
                                      
                                          for(uint256 i = 0; i < _recipients.length; i++) {
                                            jobBalances[_jobId] = jobBalances[_jobId].sub(_amounts[i]);
                                            ERC20(renderTokenAddress).safeTransfer(_recipients[i], _amounts[i]);
                                          }
                                      
                                          emit JobBalanceUpdate(_jobId, jobBalances[_jobId]);
                                        }
                                      
                                        /**
                                         * @dev Add RNDR tokens to a job
                                         *
                                         * This can only be called by a function on the RNDR token contract
                                         * @param _jobId the ID of the job used in the jobBalances mapping
                                         * @param _tokens the number of tokens sent by the artist to fund the job
                                         */
                                        function fundJob(string _jobId, uint256 _tokens) external {
                                          // Jobs can only be created by the address stored in the renderTokenAddress variable
                                          require(msg.sender == renderTokenAddress, "message sender not authorized");
                                          jobBalances[_jobId] = jobBalances[_jobId].add(_tokens);
                                      
                                          emit JobBalanceUpdate(_jobId, jobBalances[_jobId]);
                                        }
                                      
                                        /**
                                         * @dev See the tokens available for a job
                                         *
                                         * @param _jobId the ID used to lookup the job balance
                                         */
                                        function jobBalance(string _jobId) external view returns(uint256) {
                                          return jobBalances[_jobId];
                                        }
                                      
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/contracts/MigratableERC20.sol
                                      
                                      /**
                                       * @title MigratableERC20
                                       * @dev This strategy carries out an optional migration of the token balances. This migration is performed and paid for
                                       * @dev by the token holders. The new token contract starts with no initial supply and no balances. The only way to
                                       * @dev "mint" the new tokens is for users to "turn in" their old ones. This is done by first approving the amount they
                                       * @dev want to migrate via `ERC20.approve(newTokenAddress, amountToMigrate)` and then calling a function of the new
                                       * @dev token called `migrateTokens`. The old tokens are sent to a burn address, and the holder receives an equal amount
                                       * @dev in the new contract.
                                       */
                                      contract MigratableERC20 is Migratable {
                                        using SafeERC20 for ERC20;
                                      
                                        /// Burn address where the old tokens are going to be transferred
                                        address public constant BURN_ADDRESS = address(0xdead);
                                      
                                        /// Address of the old token contract
                                        ERC20 public legacyToken;
                                      
                                        /**
                                         * @dev Initializes the new token contract
                                         * @param _legacyToken address of the old token contract
                                         */
                                        function initialize(address _legacyToken) isInitializer("OptInERC20Migration", "1.9.0") public {
                                          legacyToken = ERC20(_legacyToken);
                                        }
                                      
                                        /**
                                         * @dev Migrates the total balance of the token holder to this token contract
                                         * @dev This function will burn the old token balance and mint the same balance in the new token contract
                                         */
                                        function migrate() public {
                                          uint256 amount = legacyToken.balanceOf(msg.sender);
                                          migrateToken(amount);
                                        }
                                      
                                        /**
                                         * @dev Migrates the given amount of old-token balance to the new token contract
                                         * @dev This function will burn a given amount of tokens from the old contract and mint the same amount in the new one
                                         * @param _amount uint256 representing the amount of tokens to be migrated
                                         */
                                        function migrateToken(uint256 _amount) public {
                                          migrateTokenTo(msg.sender, _amount);
                                        }
                                      
                                        /**
                                         * @dev Burns a given amount of the old token contract for a token holder and mints the same amount of
                                         * @dev new tokens for a given recipient address
                                         * @param _amount uint256 representing the amount of tokens to be migrated
                                         * @param _to address the recipient that will receive the new minted tokens
                                         */
                                        function migrateTokenTo(address _to, uint256 _amount) public {
                                          _mintMigratedTokens(_to, _amount);
                                          legacyToken.safeTransferFrom(msg.sender, BURN_ADDRESS, _amount);
                                        }
                                      
                                        /**
                                         * @dev Internal minting function
                                         * This function must be overwritten by the implementation
                                         */
                                        function _mintMigratedTokens(address _to, uint256 _amount) internal;
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/node_modules/openzeppelin-zos/contracts/token/ERC20/BasicToken.sol
                                      
                                      /**
                                       * @title Basic token
                                       * @dev Basic version of StandardToken, with no allowances.
                                       */
                                      contract BasicToken is ERC20Basic {
                                        using SafeMath for uint256;
                                      
                                        mapping(address => uint256) balances;
                                      
                                        uint256 totalSupply_;
                                      
                                        /**
                                        * @dev total number of tokens in existence
                                        */
                                        function totalSupply() public view returns (uint256) {
                                          return totalSupply_;
                                        }
                                      
                                        /**
                                        * @dev transfer token for a specified address
                                        * @param _to The address to transfer to.
                                        * @param _value The amount to be transferred.
                                        */
                                        function transfer(address _to, uint256 _value) public returns (bool) {
                                          require(_to != address(0));
                                          require(_value <= balances[msg.sender]);
                                      
                                          balances[msg.sender] = balances[msg.sender].sub(_value);
                                          balances[_to] = balances[_to].add(_value);
                                          emit Transfer(msg.sender, _to, _value);
                                          return true;
                                        }
                                      
                                        /**
                                        * @dev Gets the balance of the specified address.
                                        * @param _owner The address to query the the balance of.
                                        * @return An uint256 representing the amount owned by the passed address.
                                        */
                                        function balanceOf(address _owner) public view returns (uint256) {
                                          return balances[_owner];
                                        }
                                      
                                      }
                                      
                                      // File: /Users/matthewmcclure/repos/Token-Audit/node_modules/openzeppelin-zos/contracts/token/ERC20/StandardToken.sol
                                      
                                      /**
                                       * @title Standard ERC20 token
                                       *
                                       * @dev Implementation of the basic standard token.
                                       * @dev https://github.com/ethereum/EIPs/issues/20
                                       * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
                                       */
                                      contract StandardToken is ERC20, BasicToken {
                                      
                                        mapping (address => mapping (address => uint256)) internal allowed;
                                      
                                      
                                        /**
                                         * @dev Transfer tokens from one address to another
                                         * @param _from address The address which you want to send tokens from
                                         * @param _to address The address which you want to transfer to
                                         * @param _value uint256 the amount of tokens to be transferred
                                         */
                                        function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
                                          require(_to != address(0));
                                          require(_value <= balances[_from]);
                                          require(_value <= allowed[_from][msg.sender]);
                                      
                                          balances[_from] = balances[_from].sub(_value);
                                          balances[_to] = balances[_to].add(_value);
                                          allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
                                          emit Transfer(_from, _to, _value);
                                          return true;
                                        }
                                      
                                        /**
                                         * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
                                         *
                                         * Beware that changing an allowance with this method brings the risk that someone may use both the old
                                         * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
                                         * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
                                         * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
                                         * @param _spender The address which will spend the funds.
                                         * @param _value The amount of tokens to be spent.
                                         */
                                        function approve(address _spender, uint256 _value) public returns (bool) {
                                          allowed[msg.sender][_spender] = _value;
                                          emit Approval(msg.sender, _spender, _value);
                                          return true;
                                        }
                                      
                                        /**
                                         * @dev Function to check the amount of tokens that an owner allowed to a spender.
                                         * @param _owner address The address which owns the funds.
                                         * @param _spender address The address which will spend the funds.
                                         * @return A uint256 specifying the amount of tokens still available for the spender.
                                         */
                                        function allowance(address _owner, address _spender) public view returns (uint256) {
                                          return allowed[_owner][_spender];
                                        }
                                      
                                        /**
                                         * @dev Increase the amount of tokens that an owner allowed to a spender.
                                         *
                                         * approve should be called when allowed[_spender] == 0. To increment
                                         * allowed value is better to use this function to avoid 2 calls (and wait until
                                         * the first transaction is mined)
                                         * From MonolithDAO Token.sol
                                         * @param _spender The address which will spend the funds.
                                         * @param _addedValue The amount of tokens to increase the allowance by.
                                         */
                                        function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
                                          allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
                                          emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
                                          return true;
                                        }
                                      
                                        /**
                                         * @dev Decrease the amount of tokens that an owner allowed to a spender.
                                         *
                                         * approve should be called when allowed[_spender] == 0. To decrement
                                         * allowed value is better to use this function to avoid 2 calls (and wait until
                                         * the first transaction is mined)
                                         * From MonolithDAO Token.sol
                                         * @param _spender The address which will spend the funds.
                                         * @param _subtractedValue The amount of tokens to decrease the allowance by.
                                         */
                                        function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
                                          uint oldValue = allowed[msg.sender][_spender];
                                          if (_subtractedValue > oldValue) {
                                            allowed[msg.sender][_spender] = 0;
                                          } else {
                                            allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
                                          }
                                          emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
                                          return true;
                                        }
                                      
                                      }
                                      
                                      // File: contracts/RenderToken.sol
                                      
                                      // Escrow constract
                                      
                                      
                                      
                                      
                                      
                                      
                                      /**
                                       * @title RenderToken
                                       * @dev ERC20 mintable token
                                       * The token will be minted by the crowdsale contract only
                                       */
                                      contract RenderToken is Migratable, MigratableERC20, Ownable, StandardToken {
                                      
                                        string public constant name = "Render Token";
                                        string public constant symbol = "RNDR";
                                        uint8 public constant decimals = 18;
                                      
                                        // The address of the contract that manages job balances. Address is used for forwarding tokens
                                        // that come in to fund jobs
                                        address public escrowContractAddress;
                                      
                                        // Emit new contract address when escrowContractAddress has been changed
                                        event EscrowContractAddressUpdate(address escrowContractAddress);
                                        // Emit information related to tokens being escrowed
                                        event TokensEscrowed(address indexed sender, string jobId, uint256 amount);
                                        // Emit information related to legacy tokens being migrated
                                        event TokenMigration(address indexed receiver, uint256 amount);
                                      
                                        /**
                                         * @dev Initailization
                                         * @param _owner because this contract uses proxies, owner must be passed in as a param
                                         */
                                        function initialize(address _owner, address _legacyToken) public isInitializer("RenderToken", "0") {
                                          require(_owner != address(0), "_owner must not be null");
                                          require(_legacyToken != address(0), "_legacyToken must not be null");
                                          Ownable.initialize(_owner);
                                          MigratableERC20.initialize(_legacyToken);
                                        }
                                      
                                        /**
                                         * @dev Take tokens prior to beginning a job
                                         *
                                         * This function is called by the artist, and it will transfer tokens
                                         * to a separate escrow contract to be held until the job is completed
                                         * @param _jobID is the ID of the job used within the ORC backend
                                         * @param _amount is the number of RNDR tokens being held in escrow
                                         */
                                        function holdInEscrow(string _jobID, uint256 _amount) public {
                                          require(transfer(escrowContractAddress, _amount), "token transfer to escrow address failed");
                                          Escrow(escrowContractAddress).fundJob(_jobID, _amount);
                                      
                                          emit TokensEscrowed(msg.sender, _jobID, _amount);
                                        }
                                      
                                        /**
                                         * @dev Mints new tokens equal to the amount of legacy tokens burned
                                         *
                                         * This function is called internally, but triggered by a user choosing to
                                         * migrate their balance.
                                         * @param _to is the address tokens will be sent to
                                         * @param _amount is the number of RNDR tokens being sent to the address
                                         */
                                        function _mintMigratedTokens(address _to, uint256 _amount) internal {
                                          require(_to != address(0), "_to address must not be null");
                                          totalSupply_ = totalSupply_.add(_amount);
                                          balances[_to] = balances[_to].add(_amount);
                                      
                                          emit TokenMigration(_to, _amount);
                                          emit Transfer(address(0), _to, _amount);
                                        }
                                      
                                        /**
                                         * @dev Set the address of the escrow contract
                                         *
                                         * This will dictate the contract that will hold tokens in escrow and keep
                                         * a ledger of funds available for jobs.
                                         * RNDR is still in its infancy, and changes may need to be made to this
                                         * contract and / or the escrow contract. Including methods to update the
                                         * addresses allows the contracts to update independently.
                                         * If the escrow contract is ever migrated to another address for
                                         * either added security or functionality, this will need to be called.
                                         * @param _escrowAddress see escrowContractAddress
                                         */
                                        function setEscrowContractAddress(address _escrowAddress) public onlyOwner {
                                          require(_escrowAddress != address(0), "_escrowAddress must not be null");
                                          escrowContractAddress = _escrowAddress;
                                      
                                          emit EscrowContractAddressUpdate(escrowContractAddress);
                                        }
                                      
                                      }

                                      File 11 of 11: UniswapV3Feature
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity >=0.6.5 <0.9;
                                      interface IERC20Token {
                                          event Transfer(address indexed from, address indexed to, uint256 value);
                                          event Approval(address indexed owner, address indexed spender, uint256 value);
                                          /// @dev send `value` token to `to` from `msg.sender`
                                          /// @param to The address of the recipient
                                          /// @param value The amount of token to be transferred
                                          /// @return True if transfer was successful
                                          function transfer(address to, uint256 value) external returns (bool);
                                          /// @dev send `value` token to `to` from `from` on the condition it is approved by `from`
                                          /// @param from The address of the sender
                                          /// @param to The address of the recipient
                                          /// @param value The amount of token to be transferred
                                          /// @return True if transfer was successful
                                          function transferFrom(address from, address to, uint256 value) external returns (bool);
                                          /// @dev `msg.sender` approves `spender` to spend `value` tokens
                                          /// @param spender The address of the account able to transfer the tokens
                                          /// @param value The amount of wei to be approved for transfer
                                          /// @return Always true if the call has enough gas to complete execution
                                          function approve(address spender, uint256 value) external returns (bool);
                                          /// @dev Query total supply of token
                                          /// @return Total supply of token
                                          function totalSupply() external view returns (uint256);
                                          /// @dev Get the balance of `owner`.
                                          /// @param owner The address from which the balance will be retrieved
                                          /// @return Balance of owner
                                          function balanceOf(address owner) external view returns (uint256);
                                          /// @dev Get the allowance for `spender` to spend from `owner`.
                                          /// @param owner The address of the account owning tokens
                                          /// @param spender The address of the account able to transfer the tokens
                                          /// @return Amount of remaining tokens allowed to spent
                                          function allowance(address owner, address spender) external view returns (uint256);
                                          /// @dev Get the number of decimals this token has.
                                          function decimals() external view returns (uint8);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./IERC20Token.sol";
                                      interface IEtherToken is IERC20Token {
                                          /// @dev Wrap ether.
                                          function deposit() external payable;
                                          /// @dev Unwrap ether.
                                          function withdraw(uint256 amount) external;
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      import "./errors/LibRichErrorsV06.sol";
                                      import "./errors/LibSafeMathRichErrorsV06.sol";
                                      library LibSafeMathV06 {
                                          function safeMul(uint256 a, uint256 b) internal pure returns (uint256) {
                                              if (a == 0) {
                                                  return 0;
                                              }
                                              uint256 c = a * b;
                                              if (c / a != b) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.MULTIPLICATION_OVERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return c;
                                          }
                                          function safeDiv(uint256 a, uint256 b) internal pure returns (uint256) {
                                              if (b == 0) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.DIVISION_BY_ZERO,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              uint256 c = a / b;
                                              return c;
                                          }
                                          function safeSub(uint256 a, uint256 b) internal pure returns (uint256) {
                                              if (b > a) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.SUBTRACTION_UNDERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return a - b;
                                          }
                                          function safeAdd(uint256 a, uint256 b) internal pure returns (uint256) {
                                              uint256 c = a + b;
                                              if (c < a) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.ADDITION_OVERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return c;
                                          }
                                          function max256(uint256 a, uint256 b) internal pure returns (uint256) {
                                              return a >= b ? a : b;
                                          }
                                          function min256(uint256 a, uint256 b) internal pure returns (uint256) {
                                              return a < b ? a : b;
                                          }
                                          function safeMul128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              if (a == 0) {
                                                  return 0;
                                              }
                                              uint128 c = a * b;
                                              if (c / a != b) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.MULTIPLICATION_OVERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return c;
                                          }
                                          function safeDiv128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              if (b == 0) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.DIVISION_BY_ZERO,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              uint128 c = a / b;
                                              return c;
                                          }
                                          function safeSub128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              if (b > a) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.SUBTRACTION_UNDERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return a - b;
                                          }
                                          function safeAdd128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              uint128 c = a + b;
                                              if (c < a) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256BinOpError(
                                                          LibSafeMathRichErrorsV06.BinOpErrorCodes.ADDITION_OVERFLOW,
                                                          a,
                                                          b
                                                      )
                                                  );
                                              }
                                              return c;
                                          }
                                          function max128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              return a >= b ? a : b;
                                          }
                                          function min128(uint128 a, uint128 b) internal pure returns (uint128) {
                                              return a < b ? a : b;
                                          }
                                          function safeDowncastToUint128(uint256 a) internal pure returns (uint128) {
                                              if (a > type(uint128).max) {
                                                  LibRichErrorsV06.rrevert(
                                                      LibSafeMathRichErrorsV06.Uint256DowncastError(
                                                          LibSafeMathRichErrorsV06.DowncastErrorCodes.VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT128,
                                                          a
                                                      )
                                                  );
                                              }
                                              return uint128(a);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibRichErrorsV06 {
                                          // bytes4(keccak256("Error(string)"))
                                          bytes4 internal constant STANDARD_ERROR_SELECTOR = 0x08c379a0;
                                          /// @dev ABI encode a standard, string revert error payload.
                                          ///      This is the same payload that would be included by a `revert(string)`
                                          ///      solidity statement. It has the function signature `Error(string)`.
                                          /// @param message The error string.
                                          /// @return The ABI encoded error.
                                          function StandardError(string memory message) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(STANDARD_ERROR_SELECTOR, bytes(message));
                                          }
                                          /// @dev Reverts an encoded rich revert reason `errorData`.
                                          /// @param errorData ABI encoded error data.
                                          function rrevert(bytes memory errorData) internal pure {
                                              assembly {
                                                  revert(add(errorData, 0x20), mload(errorData))
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibSafeMathRichErrorsV06 {
                                          // bytes4(keccak256("Uint256BinOpError(uint8,uint256,uint256)"))
                                          bytes4 internal constant UINT256_BINOP_ERROR_SELECTOR = 0xe946c1bb;
                                          // bytes4(keccak256("Uint256DowncastError(uint8,uint256)"))
                                          bytes4 internal constant UINT256_DOWNCAST_ERROR_SELECTOR = 0xc996af7b;
                                          enum BinOpErrorCodes {
                                              ADDITION_OVERFLOW,
                                              MULTIPLICATION_OVERFLOW,
                                              SUBTRACTION_UNDERFLOW,
                                              DIVISION_BY_ZERO
                                          }
                                          enum DowncastErrorCodes {
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT32,
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT64,
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT96,
                                              VALUE_TOO_LARGE_TO_DOWNCAST_TO_UINT128
                                          }
                                          function Uint256BinOpError(BinOpErrorCodes errorCode, uint256 a, uint256 b) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(UINT256_BINOP_ERROR_SELECTOR, errorCode, a, b);
                                          }
                                          function Uint256DowncastError(DowncastErrorCodes errorCode, uint256 a) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(UINT256_DOWNCAST_ERROR_SELECTOR, errorCode, a);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2020 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      interface IOwnableV06 {
                                          /// @dev Emitted by Ownable when ownership is transferred.
                                          /// @param previousOwner The previous owner of the contract.
                                          /// @param newOwner The new owner of the contract.
                                          event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
                                          /// @dev Transfers ownership of the contract to a new address.
                                          /// @param newOwner The address that will become the owner.
                                          function transferOwnership(address newOwner) external;
                                          /// @dev The owner of this contract.
                                          /// @return ownerAddress The owner address.
                                          function owner() external view returns (address ownerAddress);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibCommonRichErrors {
                                          function OnlyCallableBySelfError(address sender) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("OnlyCallableBySelfError(address)")), sender);
                                          }
                                          function IllegalReentrancyError(bytes4 selector, uint256 reentrancyFlags) internal pure returns (bytes memory) {
                                              return
                                                  abi.encodeWithSelector(
                                                      bytes4(keccak256("IllegalReentrancyError(bytes4,uint256)")),
                                                      selector,
                                                      reentrancyFlags
                                                  );
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      library LibOwnableRichErrors {
                                          function OnlyOwnerError(address sender, address owner) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("OnlyOwnerError(address,address)")), sender, owner);
                                          }
                                          function TransferOwnerToZeroError() internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("TransferOwnerToZeroError()")));
                                          }
                                          function MigrateCallFailedError(address target, bytes memory resultData) internal pure returns (bytes memory) {
                                              return abi.encodeWithSelector(bytes4(keccak256("MigrateCallFailedError(address,bytes)")), target, resultData);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "@0x/contracts-erc20/src/IEtherToken.sol";
                                      import "../vendor/IUniswapV3Pool.sol";
                                      import "../migrations/LibMigrate.sol";
                                      import "../fixins/FixinCommon.sol";
                                      import "../fixins/FixinTokenSpender.sol";
                                      import "./interfaces/IFeature.sol";
                                      import "./interfaces/IUniswapV3Feature.sol";
                                      /// @dev VIP uniswap fill functions.
                                      contract UniswapV3Feature is IFeature, IUniswapV3Feature, FixinCommon, FixinTokenSpender {
                                          /// @dev Name of this feature.
                                          string public constant override FEATURE_NAME = "UniswapV3Feature";
                                          /// @dev Version of this feature.
                                          uint256 public immutable override FEATURE_VERSION = _encodeVersion(1, 1, 0);
                                          /// @dev WETH contract.
                                          IEtherToken private immutable WETH;
                                          /// @dev UniswapV3 Factory contract address prepended with '0xff' and left-aligned.
                                          bytes32 private immutable UNI_FF_FACTORY_ADDRESS;
                                          /// @dev UniswapV3 pool init code hash.
                                          bytes32 private immutable UNI_POOL_INIT_CODE_HASH;
                                          /// @dev Minimum size of an encoded swap path:
                                          ///      sizeof(address(inputToken) | uint24(fee) | address(outputToken))
                                          uint256 private constant SINGLE_HOP_PATH_SIZE = 20 + 3 + 20;
                                          /// @dev How many bytes to skip ahead in an encoded path to start at the next hop:
                                          ///      sizeof(address(inputToken) | uint24(fee))
                                          uint256 private constant PATH_SKIP_HOP_SIZE = 20 + 3;
                                          /// @dev The size of the swap callback data.
                                          uint256 private constant SWAP_CALLBACK_DATA_SIZE = 128;
                                          /// @dev Minimum tick price sqrt ratio.
                                          uint160 internal constant MIN_PRICE_SQRT_RATIO = 4295128739;
                                          /// @dev Minimum tick price sqrt ratio.
                                          uint160 internal constant MAX_PRICE_SQRT_RATIO = 1461446703485210103287273052203988822378723970342;
                                          /// @dev Mask of lower 20 bytes.
                                          uint256 private constant ADDRESS_MASK = 0x00ffffffffffffffffffffffffffffffffffffffff;
                                          /// @dev Mask of lower 3 bytes.
                                          uint256 private constant UINT24_MASK = 0xffffff;
                                          /// @dev Construct this contract.
                                          /// @param weth The WETH contract.
                                          /// @param uniFactory The UniswapV3 factory contract.
                                          /// @param poolInitCodeHash The UniswapV3 pool init code hash.
                                          constructor(IEtherToken weth, address uniFactory, bytes32 poolInitCodeHash) public {
                                              WETH = weth;
                                              UNI_FF_FACTORY_ADDRESS = bytes32((uint256(0xff) << 248) | (uint256(uniFactory) << 88));
                                              UNI_POOL_INIT_CODE_HASH = poolInitCodeHash;
                                          }
                                          /// @dev Initialize and register this feature.
                                          ///      Should be delegatecalled by `Migrate.migrate()`.
                                          /// @return success `LibMigrate.SUCCESS` on success.
                                          function migrate() external returns (bytes4 success) {
                                              _registerFeatureFunction(this.sellEthForTokenToUniswapV3.selector);
                                              _registerFeatureFunction(this.sellTokenForEthToUniswapV3.selector);
                                              _registerFeatureFunction(this.sellTokenForTokenToUniswapV3.selector);
                                              _registerFeatureFunction(this._sellTokenForTokenToUniswapV3.selector);
                                              _registerFeatureFunction(this._sellHeldTokenForTokenToUniswapV3.selector);
                                              _registerFeatureFunction(this.uniswapV3SwapCallback.selector);
                                              return LibMigrate.MIGRATE_SUCCESS;
                                          }
                                          /// @dev Sell attached ETH directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path, where the first token is WETH.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function sellEthForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) public payable override returns (uint256 buyAmount) {
                                              // Wrap ETH.
                                              WETH.deposit{value: msg.value}();
                                              return
                                                  _swap(
                                                      encodedPath,
                                                      msg.value,
                                                      minBuyAmount,
                                                      address(this), // we are payer because we hold the WETH
                                                      _normalizeRecipient(recipient)
                                                  );
                                          }
                                          /// @dev Sell a token for ETH directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path, where the last token is WETH.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of ETH to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of ETH bought.
                                          function sellTokenForEthToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address payable recipient
                                          ) public override returns (uint256 buyAmount) {
                                              buyAmount = _swap(
                                                  encodedPath,
                                                  sellAmount,
                                                  minBuyAmount,
                                                  msg.sender,
                                                  address(this) // we are recipient because we need to unwrap WETH
                                              );
                                              WETH.withdraw(buyAmount);
                                              // Transfer ETH to recipient.
                                              (bool success, bytes memory revertData) = _normalizeRecipient(recipient).call{value: buyAmount}("");
                                              if (!success) {
                                                  revertData.rrevert();
                                              }
                                          }
                                          /// @dev Sell a token for another token directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function sellTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) public override returns (uint256 buyAmount) {
                                              buyAmount = _swap(encodedPath, sellAmount, minBuyAmount, msg.sender, _normalizeRecipient(recipient));
                                          }
                                          /// @dev Sell a token for another token directly against uniswap v3. Internal variant.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for payer.
                                          /// @param payer The address to pull the sold tokens from.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function _sellTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient,
                                              address payer
                                          ) public override onlySelf returns (uint256 buyAmount) {
                                              buyAmount = _swap(encodedPath, sellAmount, minBuyAmount, payer, _normalizeRecipient(recipient, payer));
                                          }
                                          /// @dev Sell a token for another token directly against uniswap v3.
                                          ///      Private variant, uses tokens held by `address(this)`.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function _sellHeldTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) public override onlySelf returns (uint256 buyAmount) {
                                              buyAmount = _swap(encodedPath, sellAmount, minBuyAmount, address(this), _normalizeRecipient(recipient));
                                          }
                                          /// @dev The UniswapV3 pool swap callback which pays the funds requested
                                          ///      by the caller/pool to the pool. Can only be called by a valid
                                          ///      UniswapV3 pool.
                                          /// @param amount0Delta Token0 amount owed.
                                          /// @param amount1Delta Token1 amount owed.
                                          /// @param data Arbitrary data forwarded from swap() caller. An ABI-encoded
                                          ///        struct of: inputToken, outputToken, fee, payer
                                          function uniswapV3SwapCallback(int256 amount0Delta, int256 amount1Delta, bytes calldata data) external override {
                                              IERC20Token token0;
                                              IERC20Token token1;
                                              address payer;
                                              {
                                                  uint24 fee;
                                                  // Decode the data.
                                                  require(data.length == SWAP_CALLBACK_DATA_SIZE, "UniswapFeature/INVALID_SWAP_CALLBACK_DATA");
                                                  assembly {
                                                      let p := add(36, calldataload(68))
                                                      token0 := calldataload(p)
                                                      token1 := calldataload(add(p, 32))
                                                      fee := calldataload(add(p, 64))
                                                      payer := calldataload(add(p, 96))
                                                  }
                                                  (token0, token1) = token0 < token1 ? (token0, token1) : (token1, token0);
                                                  // Only a valid pool contract can call this function.
                                                  require(
                                                      msg.sender == address(_toPool(token0, fee, token1)),
                                                      "UniswapV3Feature/INVALID_SWAP_CALLBACK_CALLER"
                                                  );
                                              }
                                              // Pay the amount owed to the pool.
                                              if (amount0Delta > 0) {
                                                  _pay(token0, payer, msg.sender, uint256(amount0Delta));
                                              } else if (amount1Delta > 0) {
                                                  _pay(token1, payer, msg.sender, uint256(amount1Delta));
                                              } else {
                                                  revert("UniswapV3Feature/INVALID_SWAP_AMOUNTS");
                                              }
                                          }
                                          // Executes successive swaps along an encoded uniswap path.
                                          function _swap(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address payer,
                                              address recipient
                                          ) private returns (uint256 buyAmount) {
                                              if (sellAmount != 0) {
                                                  require(sellAmount <= uint256(type(int256).max), "UniswapV3Feature/SELL_AMOUNT_OVERFLOW");
                                                  // Perform a swap for each hop in the path.
                                                  bytes memory swapCallbackData = new bytes(SWAP_CALLBACK_DATA_SIZE);
                                                  while (true) {
                                                      bool isPathMultiHop = _isPathMultiHop(encodedPath);
                                                      bool zeroForOne;
                                                      IUniswapV3Pool pool;
                                                      {
                                                          (IERC20Token inputToken, uint24 fee, IERC20Token outputToken) = _decodeFirstPoolInfoFromPath(
                                                              encodedPath
                                                          );
                                                          pool = _toPool(inputToken, fee, outputToken);
                                                          zeroForOne = inputToken < outputToken;
                                                          _updateSwapCallbackData(swapCallbackData, inputToken, outputToken, fee, payer);
                                                      }
                                                      (int256 amount0, int256 amount1) = pool.swap(
                                                          // Intermediate tokens go to this contract.
                                                          isPathMultiHop ? address(this) : recipient,
                                                          zeroForOne,
                                                          int256(sellAmount),
                                                          zeroForOne ? MIN_PRICE_SQRT_RATIO + 1 : MAX_PRICE_SQRT_RATIO - 1,
                                                          swapCallbackData
                                                      );
                                                      {
                                                          int256 _buyAmount = -(zeroForOne ? amount1 : amount0);
                                                          require(_buyAmount >= 0, "UniswapV3Feature/INVALID_BUY_AMOUNT");
                                                          buyAmount = uint256(_buyAmount);
                                                      }
                                                      if (!isPathMultiHop) {
                                                          // Done.
                                                          break;
                                                      }
                                                      // Continue with next hop.
                                                      payer = address(this); // Subsequent hops are paid for by us.
                                                      sellAmount = buyAmount;
                                                      // Skip to next hop along path.
                                                      encodedPath = _shiftHopFromPathInPlace(encodedPath);
                                                  }
                                              }
                                              require(minBuyAmount <= buyAmount, "UniswapV3Feature/UNDERBOUGHT");
                                          }
                                          // Pay tokens from `payer` to `to`, using `transferFrom()` if
                                          // `payer` != this contract.
                                          function _pay(IERC20Token token, address payer, address to, uint256 amount) private {
                                              if (payer != address(this)) {
                                                  _transferERC20TokensFrom(token, payer, to, amount);
                                              } else {
                                                  _transferERC20Tokens(token, to, amount);
                                              }
                                          }
                                          // Update `swapCallbackData` in place with new values.
                                          function _updateSwapCallbackData(
                                              bytes memory swapCallbackData,
                                              IERC20Token inputToken,
                                              IERC20Token outputToken,
                                              uint24 fee,
                                              address payer
                                          ) private pure {
                                              assembly {
                                                  let p := add(swapCallbackData, 32)
                                                  mstore(p, inputToken)
                                                  mstore(add(p, 32), outputToken)
                                                  mstore(add(p, 64), and(UINT24_MASK, fee))
                                                  mstore(add(p, 96), and(ADDRESS_MASK, payer))
                                              }
                                          }
                                          // Compute the pool address given two tokens and a fee.
                                          function _toPool(
                                              IERC20Token inputToken,
                                              uint24 fee,
                                              IERC20Token outputToken
                                          ) private view returns (IUniswapV3Pool pool) {
                                              // address(keccak256(abi.encodePacked(
                                              //     hex"ff",
                                              //     UNI_FACTORY_ADDRESS,
                                              //     keccak256(abi.encode(inputToken, outputToken, fee)),
                                              //     UNI_POOL_INIT_CODE_HASH
                                              // )))
                                              bytes32 ffFactoryAddress = UNI_FF_FACTORY_ADDRESS;
                                              bytes32 poolInitCodeHash = UNI_POOL_INIT_CODE_HASH;
                                              (IERC20Token token0, IERC20Token token1) = inputToken < outputToken
                                                  ? (inputToken, outputToken)
                                                  : (outputToken, inputToken);
                                              assembly {
                                                  let s := mload(0x40)
                                                  let p := s
                                                  mstore(p, ffFactoryAddress)
                                                  p := add(p, 21)
                                                  // Compute the inner hash in-place
                                                  mstore(p, token0)
                                                  mstore(add(p, 32), token1)
                                                  mstore(add(p, 64), and(UINT24_MASK, fee))
                                                  mstore(p, keccak256(p, 96))
                                                  p := add(p, 32)
                                                  mstore(p, poolInitCodeHash)
                                                  pool := and(ADDRESS_MASK, keccak256(s, 85))
                                              }
                                          }
                                          // Return whether or not an encoded uniswap path contains more than one hop.
                                          function _isPathMultiHop(bytes memory encodedPath) private pure returns (bool isMultiHop) {
                                              return encodedPath.length > SINGLE_HOP_PATH_SIZE;
                                          }
                                          // Return the first input token, output token, and fee of an encoded uniswap path.
                                          function _decodeFirstPoolInfoFromPath(
                                              bytes memory encodedPath
                                          ) private pure returns (IERC20Token inputToken, uint24 fee, IERC20Token outputToken) {
                                              require(encodedPath.length >= SINGLE_HOP_PATH_SIZE, "UniswapV3Feature/BAD_PATH_ENCODING");
                                              assembly {
                                                  let p := add(encodedPath, 32)
                                                  inputToken := shr(96, mload(p))
                                                  p := add(p, 20)
                                                  fee := shr(232, mload(p))
                                                  p := add(p, 3)
                                                  outputToken := shr(96, mload(p))
                                              }
                                          }
                                          // Skip past the first hop of an encoded uniswap path in-place.
                                          function _shiftHopFromPathInPlace(bytes memory encodedPath) private pure returns (bytes memory shiftedEncodedPath) {
                                              require(encodedPath.length >= PATH_SKIP_HOP_SIZE, "UniswapV3Feature/BAD_PATH_ENCODING");
                                              uint256 shiftSize = PATH_SKIP_HOP_SIZE;
                                              uint256 newSize = encodedPath.length - shiftSize;
                                              assembly {
                                                  shiftedEncodedPath := add(encodedPath, shiftSize)
                                                  mstore(shiftedEncodedPath, newSize)
                                              }
                                          }
                                          // Convert null address values to alternative address.
                                          function _normalizeRecipient(
                                              address recipient,
                                              address alternative
                                          ) private pure returns (address payable normalizedRecipient) {
                                              return recipient == address(0) ? payable(alternative) : payable(recipient);
                                          }
                                          // Convert null address values to msg.sender.
                                          function _normalizeRecipient(address recipient) private view returns (address payable normalizedRecipient) {
                                              return _normalizeRecipient(recipient, msg.sender);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Basic interface for a feature contract.
                                      interface IFeature {
                                          /// @dev The name of this feature set.
                                          function FEATURE_NAME() external view returns (string memory name);
                                          /// @dev The version of this feature set.
                                          function FEATURE_VERSION() external view returns (uint256 version);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/interfaces/IOwnableV06.sol";
                                      /// @dev Owner management and migration features.
                                      interface IOwnableFeature is IOwnableV06 {
                                          /// @dev Emitted when `migrate()` is called.
                                          /// @param caller The caller of `migrate()`.
                                          /// @param migrator The migration contract.
                                          /// @param newOwner The address of the new owner.
                                          event Migrated(address caller, address migrator, address newOwner);
                                          /// @dev Execute a migration function in the context of the ZeroEx contract.
                                          ///      The result of the function being called should be the magic bytes
                                          ///      0x2c64c5ef (`keccack('MIGRATE_SUCCESS')`). Only callable by the owner.
                                          ///      The owner will be temporarily set to `address(this)` inside the call.
                                          ///      Before returning, the owner will be set to `newOwner`.
                                          /// @param target The migrator contract address.
                                          /// @param newOwner The address of the new owner.
                                          /// @param data The call data.
                                          function migrate(address target, bytes calldata data, address newOwner) external;
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev Basic registry management features.
                                      interface ISimpleFunctionRegistryFeature {
                                          /// @dev A function implementation was updated via `extend()` or `rollback()`.
                                          /// @param selector The function selector.
                                          /// @param oldImpl The implementation contract address being replaced.
                                          /// @param newImpl The replacement implementation contract address.
                                          event ProxyFunctionUpdated(bytes4 indexed selector, address oldImpl, address newImpl);
                                          /// @dev Roll back to a prior implementation of a function.
                                          /// @param selector The function selector.
                                          /// @param targetImpl The address of an older implementation of the function.
                                          function rollback(bytes4 selector, address targetImpl) external;
                                          /// @dev Register or replace a function.
                                          /// @param selector The function selector.
                                          /// @param impl The implementation contract for the function.
                                          function extend(bytes4 selector, address impl) external;
                                          /// @dev Retrieve the length of the rollback history for a function.
                                          /// @param selector The function selector.
                                          /// @return rollbackLength The number of items in the rollback history for
                                          ///         the function.
                                          function getRollbackLength(bytes4 selector) external view returns (uint256 rollbackLength);
                                          /// @dev Retrieve an entry in the rollback history for a function.
                                          /// @param selector The function selector.
                                          /// @param idx The index in the rollback history.
                                          /// @return impl An implementation address for the function at
                                          ///         index `idx`.
                                          function getRollbackEntryAtIndex(bytes4 selector, uint256 idx) external view returns (address impl);
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      /// @dev VIP uniswap v3 fill functions.
                                      interface IUniswapV3Feature {
                                          /// @dev Sell attached ETH directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path, where the first token is WETH.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function sellEthForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) external payable returns (uint256 buyAmount);
                                          /// @dev Sell a token for ETH directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path, where the last token is WETH.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of ETH to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of ETH bought.
                                          function sellTokenForEthToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address payable recipient
                                          ) external returns (uint256 buyAmount);
                                          /// @dev Sell a token for another token directly against uniswap v3.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function sellTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) external returns (uint256 buyAmount);
                                          /// @dev Sell a token for another token directly against uniswap v3. Internal variant.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for payer.
                                          /// @param payer The address to pull the sold tokens from.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function _sellTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient,
                                              address payer
                                          ) external returns (uint256 buyAmount);
                                          /// @dev Sell a token for another token directly against uniswap v3.
                                          ///      Private variant, uses tokens held by `address(this)`.
                                          /// @param encodedPath Uniswap-encoded path.
                                          /// @param sellAmount amount of the first token in the path to sell.
                                          /// @param minBuyAmount Minimum amount of the last token in the path to buy.
                                          /// @param recipient The recipient of the bought tokens. Can be zero for sender.
                                          /// @return buyAmount Amount of the last token in the path bought.
                                          function _sellHeldTokenForTokenToUniswapV3(
                                              bytes memory encodedPath,
                                              uint256 sellAmount,
                                              uint256 minBuyAmount,
                                              address recipient
                                          ) external returns (uint256 buyAmount);
                                          /// @dev The UniswapV3 pool swap callback which pays the funds requested
                                          ///      by the caller/pool to the pool. Can only be called by a valid
                                          ///      UniswapV3 pool.
                                          /// @param amount0Delta Token0 amount owed.
                                          /// @param amount1Delta Token1 amount owed.
                                          /// @param data Arbitrary data forwarded from swap() caller. An ABI-encoded
                                          ///        struct of: inputToken, outputToken, fee, payer
                                          function uniswapV3SwapCallback(int256 amount0Delta, int256 amount1Delta, bytes calldata data) external;
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibCommonRichErrors.sol";
                                      import "../errors/LibOwnableRichErrors.sol";
                                      import "../features/interfaces/IOwnableFeature.sol";
                                      import "../features/interfaces/ISimpleFunctionRegistryFeature.sol";
                                      /// @dev Common feature utilities.
                                      abstract contract FixinCommon {
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev The implementation address of this feature.
                                          address internal immutable _implementation;
                                          /// @dev The caller must be this contract.
                                          modifier onlySelf() virtual {
                                              if (msg.sender != address(this)) {
                                                  LibCommonRichErrors.OnlyCallableBySelfError(msg.sender).rrevert();
                                              }
                                              _;
                                          }
                                          /// @dev The caller of this function must be the owner.
                                          modifier onlyOwner() virtual {
                                              {
                                                  address owner = IOwnableFeature(address(this)).owner();
                                                  if (msg.sender != owner) {
                                                      LibOwnableRichErrors.OnlyOwnerError(msg.sender, owner).rrevert();
                                                  }
                                              }
                                              _;
                                          }
                                          constructor() internal {
                                              // Remember this feature's original address.
                                              _implementation = address(this);
                                          }
                                          /// @dev Registers a function implemented by this feature at `_implementation`.
                                          ///      Can and should only be called within a `migrate()`.
                                          /// @param selector The selector of the function whose implementation
                                          ///        is at `_implementation`.
                                          function _registerFeatureFunction(bytes4 selector) internal {
                                              ISimpleFunctionRegistryFeature(address(this)).extend(selector, _implementation);
                                          }
                                          /// @dev Encode a feature version as a `uint256`.
                                          /// @param major The major version number of the feature.
                                          /// @param minor The minor version number of the feature.
                                          /// @param revision The revision number of the feature.
                                          /// @return encodedVersion The encoded version number.
                                          function _encodeVersion(
                                              uint32 major,
                                              uint32 minor,
                                              uint32 revision
                                          ) internal pure returns (uint256 encodedVersion) {
                                              return (uint256(major) << 64) | (uint256(minor) << 32) | uint256(revision);
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-erc20/src/IERC20Token.sol";
                                      import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
                                      /// @dev Helpers for moving tokens around.
                                      abstract contract FixinTokenSpender {
                                          // Mask of the lower 20 bytes of a bytes32.
                                          uint256 private constant ADDRESS_MASK = 0x000000000000000000000000ffffffffffffffffffffffffffffffffffffffff;
                                          /// @dev Transfers ERC20 tokens from `owner` to `to`.
                                          /// @param token The token to spend.
                                          /// @param owner The owner of the tokens.
                                          /// @param to The recipient of the tokens.
                                          /// @param amount The amount of `token` to transfer.
                                          function _transferERC20TokensFrom(IERC20Token token, address owner, address to, uint256 amount) internal {
                                              require(address(token) != address(this), "FixinTokenSpender/CANNOT_INVOKE_SELF");
                                              assembly {
                                                  let ptr := mload(0x40) // free memory pointer
                                                  // selector for transferFrom(address,address,uint256)
                                                  mstore(ptr, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
                                                  mstore(add(ptr, 0x04), and(owner, ADDRESS_MASK))
                                                  mstore(add(ptr, 0x24), and(to, ADDRESS_MASK))
                                                  mstore(add(ptr, 0x44), amount)
                                                  let success := call(gas(), and(token, ADDRESS_MASK), 0, ptr, 0x64, ptr, 32)
                                                  let rdsize := returndatasize()
                                                  // Check for ERC20 success. ERC20 tokens should return a boolean,
                                                  // but some don't. We accept 0-length return data as success, or at
                                                  // least 32 bytes that starts with a 32-byte boolean true.
                                                  success := and(
                                                      success, // call itself succeeded
                                                      or(
                                                          iszero(rdsize), // no return data, or
                                                          and(
                                                              iszero(lt(rdsize, 32)), // at least 32 bytes
                                                              eq(mload(ptr), 1) // starts with uint256(1)
                                                          )
                                                      )
                                                  )
                                                  if iszero(success) {
                                                      returndatacopy(ptr, 0, rdsize)
                                                      revert(ptr, rdsize)
                                                  }
                                              }
                                          }
                                          /// @dev Transfers ERC20 tokens from ourselves to `to`.
                                          /// @param token The token to spend.
                                          /// @param to The recipient of the tokens.
                                          /// @param amount The amount of `token` to transfer.
                                          function _transferERC20Tokens(IERC20Token token, address to, uint256 amount) internal {
                                              require(address(token) != address(this), "FixinTokenSpender/CANNOT_INVOKE_SELF");
                                              assembly {
                                                  let ptr := mload(0x40) // free memory pointer
                                                  // selector for transfer(address,uint256)
                                                  mstore(ptr, 0xa9059cbb00000000000000000000000000000000000000000000000000000000)
                                                  mstore(add(ptr, 0x04), and(to, ADDRESS_MASK))
                                                  mstore(add(ptr, 0x24), amount)
                                                  let success := call(gas(), and(token, ADDRESS_MASK), 0, ptr, 0x44, ptr, 32)
                                                  let rdsize := returndatasize()
                                                  // Check for ERC20 success. ERC20 tokens should return a boolean,
                                                  // but some don't. We accept 0-length return data as success, or at
                                                  // least 32 bytes that starts with a 32-byte boolean true.
                                                  success := and(
                                                      success, // call itself succeeded
                                                      or(
                                                          iszero(rdsize), // no return data, or
                                                          and(
                                                              iszero(lt(rdsize, 32)), // at least 32 bytes
                                                              eq(mload(ptr), 1) // starts with uint256(1)
                                                          )
                                                      )
                                                  )
                                                  if iszero(success) {
                                                      returndatacopy(ptr, 0, rdsize)
                                                      revert(ptr, rdsize)
                                                  }
                                              }
                                          }
                                          /// @dev Transfers some amount of ETH to the given recipient and
                                          ///      reverts if the transfer fails.
                                          /// @param recipient The recipient of the ETH.
                                          /// @param amount The amount of ETH to transfer.
                                          function _transferEth(address payable recipient, uint256 amount) internal {
                                              if (amount > 0) {
                                                  (bool success, ) = recipient.call{value: amount}("");
                                                  require(success, "FixinTokenSpender::_transferEth/TRANSFER_FAILED");
                                              }
                                          }
                                          /// @dev Gets the maximum amount of an ERC20 token `token` that can be
                                          ///      pulled from `owner` by this address.
                                          /// @param token The token to spend.
                                          /// @param owner The owner of the tokens.
                                          /// @return amount The amount of tokens that can be pulled.
                                          function _getSpendableERC20BalanceOf(IERC20Token token, address owner) internal view returns (uint256) {
                                              return LibSafeMathV06.min256(token.allowance(owner, address(this)), token.balanceOf(owner));
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.5;
                                      pragma experimental ABIEncoderV2;
                                      import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
                                      import "../errors/LibOwnableRichErrors.sol";
                                      library LibMigrate {
                                          /// @dev Magic bytes returned by a migrator to indicate success.
                                          ///      This is `keccack('MIGRATE_SUCCESS')`.
                                          bytes4 internal constant MIGRATE_SUCCESS = 0x2c64c5ef;
                                          using LibRichErrorsV06 for bytes;
                                          /// @dev Perform a delegatecall and ensure it returns the magic bytes.
                                          /// @param target The call target.
                                          /// @param data The call data.
                                          function delegatecallMigrateFunction(address target, bytes memory data) internal {
                                              (bool success, bytes memory resultData) = target.delegatecall(data);
                                              if (!success || resultData.length != 32 || abi.decode(resultData, (bytes4)) != MIGRATE_SUCCESS) {
                                                  LibOwnableRichErrors.MigrateCallFailedError(target, resultData).rrevert();
                                              }
                                          }
                                      }
                                      // SPDX-License-Identifier: Apache-2.0
                                      /*
                                        Copyright 2023 ZeroEx Intl.
                                        Licensed under the Apache License, Version 2.0 (the "License");
                                        you may not use this file except in compliance with the License.
                                        You may obtain a copy of the License at
                                          http://www.apache.org/licenses/LICENSE-2.0
                                        Unless required by applicable law or agreed to in writing, software
                                        distributed under the License is distributed on an "AS IS" BASIS,
                                        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
                                        See the License for the specific language governing permissions and
                                        limitations under the License.
                                      */
                                      pragma solidity ^0.6.12;
                                      interface IUniswapV3Pool {
                                          /// @notice Swap token0 for token1, or token1 for token0
                                          /// @dev The caller of this method receives a callback in the form of IUniswapV3SwapCallback#uniswapV3SwapCallback
                                          /// @param recipient The address to receive the output of the swap
                                          /// @param zeroForOne The direction of the swap, true for token0 to token1, false for token1 to token0
                                          /// @param amountSpecified The amount of the swap, which implicitly configures the swap as exact input (positive),
                                          /// or exact output (negative)
                                          /// @param sqrtPriceLimitX96 The Q64.96 sqrt price limit. If zero for one, the price cannot be less than this
                                          /// value after the swap. If one for zero, the price cannot be greater than this value after the swap
                                          /// @param data Any data to be passed through to the callback
                                          /// @return amount0 The delta of the balance of token0 of the pool, exact when negative, minimum when positive
                                          /// @return amount1 The delta of the balance of token1 of the pool, exact when negative, minimum when positive
                                          function swap(
                                              address recipient,
                                              bool zeroForOne,
                                              int256 amountSpecified,
                                              uint160 sqrtPriceLimitX96,
                                              bytes calldata data
                                          ) external returns (int256 amount0, int256 amount1);
                                      }