ETH Price: $2,643.32 (+3.65%)

Transaction Decoder

Block:
22709701 at Jun-15-2025 11:40:11 AM +UTC
Transaction Fee:
0.000283346898485536 ETH $0.75
Gas Used:
204,718 Gas / 1.384083952 Gwei

Emitted Events:

204 DexRouter.SwapOrderId( id=112925 )
205 WETH9.Deposit( dst=DexRouter, wad=59475000000000000 )
206 WETH9.Transfer( src=DexRouter, dst=UniswapV2Pair, wad=59475000000000000 )
207 VraToken.Sent( operator=UniswapV2Pair, from=UniswapV2Pair, to=Spender, amount=115313407852509835777404, data=0x, operatorData=0x )
208 VraToken.Transfer( from=UniswapV2Pair, to=Spender, value=115313407852509835777404 )
209 UniswapV2Pair.Sync( reserve0=64163917121267814162, reserve1=124663215025275342393168509 )
210 UniswapV2Pair.Swap( sender=DexRouter, amount0In=59475000000000000, amount1In=0, amount0Out=0, amount1Out=115313407852509835777404, to=Spender )
211 DexRouter.OrderRecord( fromToken=0x00000000...000000000, toToken=VraToken, sender=[Sender] 0x269971b34c6027d5d1b49a14982e6f077e232a83, fromAmount=59475000000000000, returnAmount=115313407852509835777404 )
212 Proxy.0x3d0ce9bfc3ed7d6862dbb28b2dea94561fe714a1b4d019aa8af39730d1ad7c3d( 0x3d0ce9bfc3ed7d6862dbb28b2dea94561fe714a1b4d019aa8af39730d1ad7c3d, 0x00000000000000000000000074de5d4fcbf63e00296fd95d33236b9794016631, 0000000000000000000000000000000000000000000000000001dd7c1681d000 )
213 VraToken.Sent( operator=Spender, from=Spender, to=[Sender] 0x269971b34c6027d5d1b49a14982e6f077e232a83, amount=115313407852509835777404, data=0x, operatorData=0x )
214 VraToken.Transfer( from=Spender, to=[Sender] 0x269971b34c6027d5d1b49a14982e6f077e232a83, value=115313407852509835777404 )
215 MetaSwap.Swap( 0xbeee1e6e7fe307ddcf84b0a16137a4430ad5e2480fc4f4a8e250ab56ccd7630d, 0xd6b6d5e0aacce0469a313983d889ed10d0bb7c9545af0285a19b4ff094b4041d, 0x000000000000000000000000269971b34c6027d5d1b49a14982e6f077e232a83 )

Account State Difference:

  Address   Before After State Difference Code
0x269971b3...77e232a83
0.061361936908913295 Eth
Nonce: 125
0.001078590010427759 Eth
Nonce: 126
0.060283346898485536
(Titan Builder)
14.816546531568448159 Eth14.816751249569267031 Eth0.000204718000818872
0x60031819...b6c2B5D75
0xC02aaA39...83C756Cc2 2,625,481.880074335837454076 Eth2,625,481.939549335837454076 Eth0.059475
0xF326e4dE...3c79f1915
(MetaMask: DS Proxy)
3,839.104480379999962742 Eth3,839.105005379999962742 Eth0.000525
0xF411903c...a66507255

Execution Trace

ETH 0.06 MetaSwap.swap( aggregatorId=okx, tokenFrom=0x0000000000000000000000000000000000000000, amount=60000000000000000, data=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
  • ETH 0.06 Spender.swap( adapter=0xa65Ed75603BeA45f821CEefE02D999AD99D2AfCA, data=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
    • ETH 0.06 0xa65ed75603bea45f821ceefe02d999ad99d2afca.92f5f037( )
      • ETH 0.059475 DexRouter.unxswapByOrderId( ) => ( returnAmount=115313407852509835777404 )
        • ETH 0.059475 WETH9.CALL( )
        • WETH9.transfer( dst=0x60031819a16266d896268cfEa5d5be0b6c2B5D75, wad=59475000000000000 ) => ( True )
        • UniswapV2Pair.STATICCALL( )
        • VraToken.balanceOf( tokenHolder=0x74de5d4FCbf63E00296fd95d33236B9794016631 ) => ( 0 )
        • UniswapV2Pair.STATICCALL( )
        • UniswapV2Pair.STATICCALL( )
        • WETH9.balanceOf( 0x60031819a16266d896268cfEa5d5be0b6c2B5D75 ) => ( 64163917121267814162 )
        • UniswapV2Pair.swap( amount0Out=0, amount1Out=115313407852509835777404, to=0x74de5d4FCbf63E00296fd95d33236B9794016631, data=0x )
          • VraToken.transfer( recipient=0x74de5d4FCbf63E00296fd95d33236B9794016631, amount=115313407852509835777404 ) => ( True )
            • ERC1820Registry.getInterfaceImplementer( _addr=0x60031819a16266d896268cfEa5d5be0b6c2B5D75, _interfaceHash=29DDB589B1FB5FC7CF394961C1ADF5F8C6454761ADF795E67FE149F658ABE895 ) => ( 0x0000000000000000000000000000000000000000 )
            • ERC1820Registry.getInterfaceImplementer( _addr=0x74de5d4FCbf63E00296fd95d33236B9794016631, _interfaceHash=B281FC8C12954D22544DB45DE3159A39272895B169A852B314F9CC762E44C53B ) => ( 0x0000000000000000000000000000000000000000 )
            • WETH9.balanceOf( 0x60031819a16266d896268cfEa5d5be0b6c2B5D75 ) => ( 64163917121267814162 )
            • VraToken.balanceOf( tokenHolder=0x60031819a16266d896268cfEa5d5be0b6c2B5D75 ) => ( 124663215025275342393168509 )
            • VraToken.balanceOf( tokenHolder=0x74de5d4FCbf63E00296fd95d33236B9794016631 ) => ( 115313407852509835777404 )
            • ETH 0.000525 Proxy.CALL( )
              • ETH 0.000525 GnosisSafe.DELEGATECALL( )
              • VraToken.balanceOf( tokenHolder=0x74de5d4FCbf63E00296fd95d33236B9794016631 ) => ( 115313407852509835777404 )
              • VraToken.transfer( recipient=0x269971b34C6027D5D1b49a14982e6F077e232a83, amount=115313407852509835777404 ) => ( True )
                • ERC1820Registry.getInterfaceImplementer( _addr=0x74de5d4FCbf63E00296fd95d33236B9794016631, _interfaceHash=29DDB589B1FB5FC7CF394961C1ADF5F8C6454761ADF795E67FE149F658ABE895 ) => ( 0x0000000000000000000000000000000000000000 )
                • ERC1820Registry.getInterfaceImplementer( _addr=0x269971b34C6027D5D1b49a14982e6F077e232a83, _interfaceHash=B281FC8C12954D22544DB45DE3159A39272895B169A852B314F9CC762E44C53B ) => ( 0x0000000000000000000000000000000000000000 )
                  File 1 of 9: MetaSwap
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                  import "@openzeppelin/contracts/utils/Address.sol";
                  import "../Constants.sol";
                  contract CommonAdapter {
                      using SafeERC20 for IERC20;
                      using Address for address;
                      using Address for address payable;
                      /**
                       * @dev Performs a swap
                       * @param recipient The original msg.sender performing the swap
                       * @param aggregator Address of the aggregator's contract
                       * @param spender Address to which tokens will be approved
                       * @param method Selector of the function to be called in the aggregator's contract
                       * @param tokenFrom Token to be swapped
                       * @param tokenTo Token to be received
                       * @param amountFrom Amount of tokenFrom to swap
                       * @param amountTo Minimum amount of tokenTo to receive
                       * @param data Data used for the call made to the aggregator's contract
                       */
                      function swap(
                          address payable recipient,
                          address aggregator,
                          address spender,
                          bytes4 method,
                          IERC20 tokenFrom,
                          IERC20 tokenTo,
                          uint256 amountFrom,
                          uint256 amountTo,
                          bytes calldata data
                      ) external payable {
                          require(tokenFrom != tokenTo, "TOKEN_PAIR_INVALID");
                          if (address(tokenFrom) != Constants.ETH) {
                              _approveSpender(tokenFrom, spender, amountFrom);
                          }
                          // We always forward msg.value as it may be necessary to pay fees
                          bytes memory encodedData = abi.encodePacked(method, data);
                          aggregator.functionCallWithValue(encodedData, msg.value);
                          // Transfer remaining balance of tokenFrom to sender
                          if (address(tokenFrom) != Constants.ETH) {
                              uint256 balance = tokenFrom.balanceOf(address(this));
                              _transfer(tokenFrom, balance, recipient);
                          }
                          uint256 weiBalance = address(this).balance;
                          // Transfer remaining balance of tokenTo to sender
                          if (address(tokenTo) != Constants.ETH) {
                              uint256 balance = tokenTo.balanceOf(address(this));
                              require(balance >= amountTo, "INSUFFICIENT_AMOUNT");
                              _transfer(tokenTo, balance, recipient);
                          } else {
                              // If tokenTo == ETH, then check that the remaining ETH balance >= amountTo
                              require(weiBalance >= amountTo, "INSUFFICIENT_AMOUNT");
                          }
                          // If there are unused fees or if tokenTo is ETH, transfer to sender
                          if (weiBalance > 0) {
                              recipient.sendValue(weiBalance);
                          }
                      }
                      /**
                       * @dev Transfers token to sender if amount > 0
                       * @param token IERC20 token to transfer to sender
                       * @param amount Amount of token to transfer
                       * @param recipient Address that will receive the tokens
                       */
                      function _transfer(
                          IERC20 token,
                          uint256 amount,
                          address recipient
                      ) internal {
                          if (amount > 0) {
                              token.safeTransfer(recipient, amount);
                          }
                      }
                      // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/SafeERC20.sol
                      /**
                       * @dev Approves max amount of token to the spender if the allowance is lower than amount
                       * @param token The ERC20 token to approve
                       * @param spender Address to which funds will be approved
                       * @param amount Amount used to compare current allowance
                       */
                      function _approveSpender(
                          IERC20 token,
                          address spender,
                          uint256 amount
                      ) internal {
                          // If allowance is not enough, approve max possible amount
                          uint256 allowance = token.allowance(address(this), spender);
                          if (allowance < amount) {
                              bytes memory returndata = address(token).functionCall(
                                  abi.encodeWithSelector(
                                      token.approve.selector,
                                      spender,
                                      type(uint256).max
                                  )
                              );
                              if (returndata.length > 0) {
                                  // Return data is optional
                                  require(abi.decode(returndata, (bool)), "APPROVAL_FAILED");
                              }
                          }
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.0;
                  /**
                   * @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;
                  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 ^0.6.0;
                  /**
                   * @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, 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) {
                          return sub(a, b, "SafeMath: subtraction overflow");
                      }
                      /**
                       * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                       * overflow (when the result is negative).
                       *
                       * 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);
                          uint256 c = a - b;
                          return c;
                      }
                      /**
                       * @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) {
                          // 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 0;
                          }
                          uint256 c = a * b;
                          require(c / a == b, "SafeMath: multiplication overflow");
                          return c;
                      }
                      /**
                       * @dev Returns the integer division of two unsigned integers. Reverts 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) {
                          return div(a, b, "SafeMath: division by zero");
                      }
                      /**
                       * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
                          require(b > 0, errorMessage);
                          uint256 c = a / b;
                          // assert(a == b * c + a % b); // There is no case in which this doesn't hold
                          return c;
                      }
                      /**
                       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                       * Reverts 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) {
                          return mod(a, b, "SafeMath: modulo by zero");
                      }
                      /**
                       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                       * Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
                          require(b != 0, errorMessage);
                          return a % b;
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.2;
                  /**
                   * @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 in 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");
                          return _functionCallWithValue(target, data, value, errorMessage);
                      }
                      function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
                          require(isContract(target), "Address: call to non-contract");
                          // solhint-disable-next-line avoid-low-level-calls
                          (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
                          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;
                  library Constants {
                      address internal constant ETH = 0x0000000000000000000000000000000000000000;
                  }
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                  import "@openzeppelin/contracts/math/SafeMath.sol";
                  import "@openzeppelin/contracts/utils/Address.sol";
                  import "../Constants.sol";
                  contract FeeCommonAdapter {
                      using SafeERC20 for IERC20;
                      using Address for address;
                      using Address for address payable;
                      using SafeMath for uint256;
                      // solhint-disable-next-line var-name-mixedcase
                      address payable public immutable FEE_WALLET;
                      constructor(address payable feeWallet) public {
                          FEE_WALLET = feeWallet;
                      }
                      /**
                       * @dev Performs a swap
                       * @param recipient The original msg.sender performing the swap
                       * @param aggregator Address of the aggregator's contract
                       * @param spender Address to which tokens will be approved
                       * @param method Selector of the function to be called in the aggregator's contract
                       * @param tokenFrom Token to be swapped
                       * @param tokenTo Token to be received
                       * @param amountFrom Amount of tokenFrom to swap
                       * @param amountTo Minimum amount of tokenTo to receive
                       * @param data Data used for the call made to the aggregator's contract
                       * @param fee Amount of tokenFrom sent to the fee wallet
                       */
                      function swap(
                          address payable recipient,
                          address aggregator,
                          address spender,
                          bytes4 method,
                          IERC20 tokenFrom,
                          IERC20 tokenTo,
                          uint256 amountFrom,
                          uint256 amountTo,
                          bytes calldata data,
                          uint256 fee
                      ) external payable {
                          require(tokenFrom != tokenTo, "TOKEN_PAIR_INVALID");
                          if (address(tokenFrom) == Constants.ETH) {
                              FEE_WALLET.sendValue(fee);
                          } else {
                              _transfer(tokenFrom, fee, FEE_WALLET);
                              _approveSpender(tokenFrom, spender, amountFrom);
                          }
                          // We always forward msg.value as it may be necessary to pay fees
                          aggregator.functionCallWithValue(
                              abi.encodePacked(method, data),
                              address(this).balance
                          );
                          // Transfer remaining balance of tokenFrom to sender
                          if (address(tokenFrom) != Constants.ETH) {
                              _transfer(tokenFrom, tokenFrom.balanceOf(address(this)), recipient);
                          }
                          uint256 weiBalance = address(this).balance;
                          // Transfer remaining balance of tokenTo to sender
                          if (address(tokenTo) != Constants.ETH) {
                              uint256 balance = tokenTo.balanceOf(address(this));
                              require(balance >= amountTo, "INSUFFICIENT_AMOUNT");
                              _transfer(tokenTo, balance, recipient);
                          } else {
                              // If tokenTo == ETH, then check that the remaining ETH balance >= amountTo
                              require(weiBalance >= amountTo, "INSUFFICIENT_AMOUNT");
                          }
                          // If there are unused fees or if tokenTo is ETH, transfer to sender
                          if (weiBalance > 0) {
                              recipient.sendValue(weiBalance);
                          }
                      }
                      /**
                       * @dev Transfers token to sender if amount > 0
                       * @param token IERC20 token to transfer to sender
                       * @param amount Amount of token to transfer
                       * @param recipient Address that will receive the tokens
                       */
                      function _transfer(
                          IERC20 token,
                          uint256 amount,
                          address recipient
                      ) internal {
                          if (amount > 0) {
                              token.safeTransfer(recipient, amount);
                          }
                      }
                      // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/SafeERC20.sol
                      /**
                       * @dev Approves max amount of token to the spender if the allowance is lower than amount
                       * @param token The ERC20 token to approve
                       * @param spender Address to which funds will be approved
                       * @param amount Amount used to compare current allowance
                       */
                      function _approveSpender(
                          IERC20 token,
                          address spender,
                          uint256 amount
                      ) internal {
                          // If allowance is not enough, approve max possible amount
                          uint256 allowance = token.allowance(address(this), spender);
                          if (allowance < amount) {
                              bytes memory returndata = address(token).functionCall(
                                  abi.encodeWithSelector(
                                      token.approve.selector,
                                      spender,
                                      type(uint256).max
                                  )
                              );
                              if (returndata.length > 0) {
                                  // Return data is optional
                                  require(abi.decode(returndata, (bool)), "APPROVAL_FAILED");
                              }
                          }
                      }
                  }
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                  import "@openzeppelin/contracts/math/SafeMath.sol";
                  import "@openzeppelin/contracts/utils/Address.sol";
                  import "../Constants.sol";
                  import "../IWETH.sol";
                  contract FeeWethAdapter {
                      using SafeERC20 for IERC20;
                      using Address for address;
                      using Address for address payable;
                      using SafeMath for uint256;
                      IWETH public immutable weth;
                      // solhint-disable-next-line var-name-mixedcase
                      address payable public immutable FEE_WALLET;
                      constructor(IWETH _weth, address payable feeWallet) public {
                          weth = _weth;
                          FEE_WALLET = feeWallet;
                      }
                      /**
                       * @dev Performs a swap
                       * @param recipient The original msg.sender performing the swap
                       * @param aggregator Address of the aggregator's contract
                       * @param spender Address to which tokens will be approved
                       * @param method Selector of the function to be called in the aggregator's contract
                       * @param tokenFrom Token to be swapped
                       * @param tokenTo Token to be received
                       * @param amountFrom Amount of tokenFrom to swap
                       * @param amountTo Minimum amount of tokenTo to receive
                       * @param data Data used for the call made to the aggregator's contract
                       * @param fee Amount of tokenFrom sent to the fee wallet
                       */
                      function swap(
                          address payable recipient,
                          address aggregator,
                          address spender,
                          bytes4 method,
                          IERC20 tokenFrom,
                          IERC20 tokenTo,
                          uint256 amountFrom,
                          uint256 amountTo,
                          bytes calldata data,
                          uint256 fee
                      ) external payable {
                          require(tokenFrom != tokenTo, "TOKEN_PAIR_INVALID");
                          if (address(tokenFrom) == Constants.ETH) {
                              FEE_WALLET.sendValue(fee);
                              // If tokenFrom is ETH, msg.value = fee + amountFrom (total fee could be 0)
                              // Can't deal with ETH, convert to WETH, the remaining balance will be the fee
                              weth.deposit{value: amountFrom}();
                              _approveSpender(weth, spender, amountFrom);
                          } else {
                              _transfer(tokenFrom, fee, FEE_WALLET);
                              // Otherwise capture tokens from sender
                              _approveSpender(tokenFrom, spender, amountFrom);
                          }
                          // Perform the swap
                          aggregator.functionCallWithValue(
                              abi.encodePacked(method, data),
                              address(this).balance
                          );
                          // Transfer remaining balance of tokenFrom to sender
                          if (address(tokenFrom) != Constants.ETH) {
                              _transfer(tokenFrom, tokenFrom.balanceOf(address(this)), recipient);
                          } else {
                              // If using ETH, just unwrap any remaining WETH
                              // At the end of this function all ETH will be transferred to the sender
                              _unwrapWETH();
                          }
                          uint256 weiBalance = address(this).balance;
                          // Transfer remaining balance of tokenTo to sender
                          if (address(tokenTo) != Constants.ETH) {
                              uint256 balance = tokenTo.balanceOf(address(this));
                              require(balance >= amountTo, "INSUFFICIENT_AMOUNT");
                              _transfer(tokenTo, balance, recipient);
                          } else {
                              // If tokenTo == ETH, unwrap received WETH and add it to the wei balance,
                              // then check that the remaining ETH balance >= amountTo
                              // It is safe to not use safeMath as no one can have enough Ether to overflow
                              weiBalance += _unwrapWETH();
                              require(weiBalance >= amountTo, "INSUFFICIENT_AMOUNT");
                          }
                          // If there are unused fees or if tokenTo is ETH, transfer to sender
                          if (weiBalance > 0) {
                              recipient.sendValue(weiBalance);
                          }
                      }
                      /**
                       * @dev Unwraps all available WETH into ETH
                       */
                      function _unwrapWETH() internal returns (uint256) {
                          uint256 balance = weth.balanceOf(address(this));
                          weth.withdraw(balance);
                          return balance;
                      }
                      /**
                       * @dev Transfers token to sender if amount > 0
                       * @param token IERC20 token to transfer to sender
                       * @param amount Amount of token to transfer
                       * @param recipient Address that will receive the tokens
                       */
                      function _transfer(
                          IERC20 token,
                          uint256 amount,
                          address recipient
                      ) internal {
                          if (amount > 0) {
                              token.safeTransfer(recipient, amount);
                          }
                      }
                      // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/SafeERC20.sol
                      /**
                       * @dev Approves max amount of token to the spender if the allowance is lower than amount
                       * @param token The ERC20 token to approve
                       * @param spender Address to which funds will be approved
                       * @param amount Amount used to compare current allowance
                       */
                      function _approveSpender(
                          IERC20 token,
                          address spender,
                          uint256 amount
                      ) internal {
                          // If allowance is not enough, approve max possible amount
                          uint256 allowance = token.allowance(address(this), spender);
                          if (allowance < amount) {
                              bytes memory returndata = address(token).functionCall(
                                  abi.encodeWithSelector(
                                      token.approve.selector,
                                      spender,
                                      type(uint256).max
                                  )
                              );
                              if (returndata.length > 0) {
                                  // Return data is optional
                                  require(abi.decode(returndata, (bool)), "APPROVAL_FAILED");
                              }
                          }
                      }
                  }
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  interface IWETH is IERC20 {
                      function deposit() external payable;
                      function withdraw(uint256) external;
                  }
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                  import "@openzeppelin/contracts/math/SafeMath.sol";
                  import "@openzeppelin/contracts/utils/Address.sol";
                  import "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";
                  import "../Constants.sol";
                  contract UniswapAdapter {
                      using SafeERC20 for IERC20;
                      using Address for address;
                      using Address for address payable;
                      using SafeMath for uint256;
                      // solhint-disable-next-line var-name-mixedcase
                      IUniswapV2Router02 public immutable UNISWAP;
                      // solhint-disable-next-line var-name-mixedcase
                      address payable public immutable FEE_WALLET;
                      constructor(address payable feeWallet, IUniswapV2Router02 uniswap) public {
                          FEE_WALLET = feeWallet;
                          UNISWAP = uniswap;
                      }
                      /**
                       * @dev Performs a swap
                       * @param recipient The original msg.sender performing the swap
                       * @param tokenFrom Token to be swapped
                       * @param tokenTo Token to be received
                       * @param amountFrom Amount of tokenFrom to swap
                       * @param amountTo Minimum amount of tokenTo to receive
                       * @param path Used by Uniswap
                       * @param deadline Timestamp at which the swap becomes invalid. Used by Uniswap
                       * @param feeOnTransfer Use `supportingFeeOnTransfer` Uniswap methods
                       * @param fee Amount of tokenFrom sent to the fee wallet
                       */
                      function swap(
                          address payable recipient,
                          IERC20 tokenFrom,
                          IERC20 tokenTo,
                          uint256 amountFrom,
                          uint256 amountTo,
                          address[] calldata path,
                          uint256 deadline,
                          bool feeOnTransfer,
                          uint256 fee
                      ) external payable {
                          require(tokenFrom != tokenTo, "TOKEN_PAIR_INVALID");
                          if (address(tokenFrom) == Constants.ETH) {
                              FEE_WALLET.sendValue(fee);
                          } else {
                              _transfer(tokenFrom, fee, FEE_WALLET);
                          }
                          if (address(tokenFrom) == Constants.ETH) {
                              if (feeOnTransfer) {
                                  UNISWAP.swapExactETHForTokensSupportingFeeOnTransferTokens{
                                      value: address(this).balance
                                  }(amountTo, path, address(this), deadline);
                              } else {
                                  UNISWAP.swapExactETHForTokens{value: address(this).balance}(
                                      amountTo,
                                      path,
                                      address(this),
                                      deadline
                                  );
                              }
                          } else {
                              _approveSpender(tokenFrom, address(UNISWAP), amountFrom);
                              if (address(tokenTo) == Constants.ETH) {
                                  if (feeOnTransfer) {
                                      UNISWAP.swapExactTokensForETHSupportingFeeOnTransferTokens(
                                          amountFrom,
                                          amountTo,
                                          path,
                                          address(this),
                                          deadline
                                      );
                                  } else {
                                      UNISWAP.swapExactTokensForETH(
                                          amountFrom,
                                          amountTo,
                                          path,
                                          address(this),
                                          deadline
                                      );
                                  }
                              } else {
                                  if (feeOnTransfer) {
                                      UNISWAP
                                          .swapExactTokensForTokensSupportingFeeOnTransferTokens(
                                          amountFrom,
                                          amountTo,
                                          path,
                                          address(this),
                                          deadline
                                      );
                                  } else {
                                      UNISWAP.swapExactTokensForTokens(
                                          amountFrom,
                                          amountTo,
                                          path,
                                          address(this),
                                          deadline
                                      );
                                  }
                              }
                          }
                          // Transfer remaining balance of tokenFrom to sender
                          if (address(tokenFrom) != Constants.ETH) {
                              _transfer(tokenFrom, tokenFrom.balanceOf(address(this)), recipient);
                          }
                          uint256 weiBalance = address(this).balance;
                          // Transfer remaining balance of tokenTo to sender
                          if (address(tokenTo) != Constants.ETH) {
                              uint256 balance = tokenTo.balanceOf(address(this));
                              require(balance >= amountTo, "INSUFFICIENT_AMOUNT");
                              _transfer(tokenTo, balance, recipient);
                          } else {
                              // If tokenTo == ETH, then check that the remaining ETH balance >= amountTo
                              require(weiBalance >= amountTo, "INSUFFICIENT_AMOUNT");
                          }
                          // If there are unused fees or if tokenTo is ETH, transfer to sender
                          if (weiBalance > 0) {
                              recipient.sendValue(weiBalance);
                          }
                      }
                      /**
                       * @dev Transfers token to sender if amount > 0
                       * @param token IERC20 token to transfer to sender
                       * @param amount Amount of token to transfer
                       * @param recipient Address that will receive the tokens
                       */
                      function _transfer(
                          IERC20 token,
                          uint256 amount,
                          address recipient
                      ) internal {
                          if (amount > 0) {
                              token.safeTransfer(recipient, amount);
                          }
                      }
                      // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/SafeERC20.sol
                      /**
                       * @dev Approves max amount of token to the spender if the allowance is lower than amount
                       * @param token The ERC20 token to approve
                       * @param spender Address to which funds will be approved
                       * @param amount Amount used to compare current allowance
                       */
                      function _approveSpender(
                          IERC20 token,
                          address spender,
                          uint256 amount
                      ) internal {
                          // If allowance is not enough, approve max possible amount
                          uint256 allowance = token.allowance(address(this), spender);
                          if (allowance < amount) {
                              bytes memory returndata = address(token).functionCall(
                                  abi.encodeWithSelector(
                                      token.approve.selector,
                                      spender,
                                      type(uint256).max
                                  )
                              );
                              if (returndata.length > 0) {
                                  // Return data is optional
                                  require(abi.decode(returndata, (bool)), "APPROVAL_FAILED");
                              }
                          }
                      }
                  }
                  pragma solidity >=0.6.2;
                  import './IUniswapV2Router01.sol';
                  interface IUniswapV2Router02 is IUniswapV2Router01 {
                      function removeLiquidityETHSupportingFeeOnTransferTokens(
                          address token,
                          uint liquidity,
                          uint amountTokenMin,
                          uint amountETHMin,
                          address to,
                          uint deadline
                      ) external returns (uint amountETH);
                      function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
                          address token,
                          uint liquidity,
                          uint amountTokenMin,
                          uint amountETHMin,
                          address to,
                          uint deadline,
                          bool approveMax, uint8 v, bytes32 r, bytes32 s
                      ) external returns (uint amountETH);
                      function swapExactTokensForTokensSupportingFeeOnTransferTokens(
                          uint amountIn,
                          uint amountOutMin,
                          address[] calldata path,
                          address to,
                          uint deadline
                      ) external;
                      function swapExactETHForTokensSupportingFeeOnTransferTokens(
                          uint amountOutMin,
                          address[] calldata path,
                          address to,
                          uint deadline
                      ) external payable;
                      function swapExactTokensForETHSupportingFeeOnTransferTokens(
                          uint amountIn,
                          uint amountOutMin,
                          address[] calldata path,
                          address to,
                          uint deadline
                      ) external;
                  }
                  pragma solidity >=0.6.2;
                  interface IUniswapV2Router01 {
                      function factory() external pure returns (address);
                      function WETH() external pure returns (address);
                      function addLiquidity(
                          address tokenA,
                          address tokenB,
                          uint amountADesired,
                          uint amountBDesired,
                          uint amountAMin,
                          uint amountBMin,
                          address to,
                          uint deadline
                      ) external returns (uint amountA, uint amountB, uint liquidity);
                      function addLiquidityETH(
                          address token,
                          uint amountTokenDesired,
                          uint amountTokenMin,
                          uint amountETHMin,
                          address to,
                          uint deadline
                      ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
                      function removeLiquidity(
                          address tokenA,
                          address tokenB,
                          uint liquidity,
                          uint amountAMin,
                          uint amountBMin,
                          address to,
                          uint deadline
                      ) external returns (uint amountA, uint amountB);
                      function removeLiquidityETH(
                          address token,
                          uint liquidity,
                          uint amountTokenMin,
                          uint amountETHMin,
                          address to,
                          uint deadline
                      ) external returns (uint amountToken, uint amountETH);
                      function removeLiquidityWithPermit(
                          address tokenA,
                          address tokenB,
                          uint liquidity,
                          uint amountAMin,
                          uint amountBMin,
                          address to,
                          uint deadline,
                          bool approveMax, uint8 v, bytes32 r, bytes32 s
                      ) external returns (uint amountA, uint amountB);
                      function removeLiquidityETHWithPermit(
                          address token,
                          uint liquidity,
                          uint amountTokenMin,
                          uint amountETHMin,
                          address to,
                          uint deadline,
                          bool approveMax, uint8 v, bytes32 r, bytes32 s
                      ) external returns (uint amountToken, uint amountETH);
                      function swapExactTokensForTokens(
                          uint amountIn,
                          uint amountOutMin,
                          address[] calldata path,
                          address to,
                          uint deadline
                      ) external returns (uint[] memory amounts);
                      function swapTokensForExactTokens(
                          uint amountOut,
                          uint amountInMax,
                          address[] calldata path,
                          address to,
                          uint deadline
                      ) external returns (uint[] memory amounts);
                      function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
                          external
                          payable
                          returns (uint[] memory amounts);
                      function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
                          external
                          returns (uint[] memory amounts);
                      function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
                          external
                          returns (uint[] memory amounts);
                      function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
                          external
                          payable
                          returns (uint[] memory amounts);
                      function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
                      function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
                      function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
                      function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
                      function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
                  }
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                  import "@openzeppelin/contracts/utils/Address.sol";
                  import "../Constants.sol";
                  import "../IWETH.sol";
                  contract WethAdapter {
                      using SafeERC20 for IERC20;
                      using Address for address;
                      using Address for address payable;
                      IWETH public immutable weth;
                      constructor(IWETH _weth) public {
                          weth = _weth;
                      }
                      /**
                       * @dev Performs a swap
                       * @param recipient The original msg.sender performing the swap
                       * @param aggregator Address of the aggregator's contract
                       * @param spender Address to which tokens will be approved
                       * @param method Selector of the function to be called in the aggregator's contract
                       * @param tokenFrom Token to be swapped
                       * @param tokenTo Token to be received
                       * @param amountFrom Amount of tokenFrom to swap
                       * @param amountTo Minimum amount of tokenTo to receive
                       * @param data Data used for the call made to the aggregator's contract
                       */
                      function swap(
                          address payable recipient,
                          address aggregator,
                          address spender,
                          bytes4 method,
                          IERC20 tokenFrom,
                          IERC20 tokenTo,
                          uint256 amountFrom,
                          uint256 amountTo,
                          bytes calldata data
                      ) external payable {
                          require(tokenFrom != tokenTo, "TOKEN_PAIR_INVALID");
                          if (address(tokenFrom) == Constants.ETH) {
                              // If tokenFrom is ETH, msg.value = fee + amountFrom (total fee could be 0)
                              // Can't deal with ETH, convert to WETH, the remaining balance will be the fee
                              weth.deposit{value: amountFrom}();
                              _approveSpender(weth, spender, amountFrom);
                          } else {
                              // Otherwise capture tokens from sender
                              _approveSpender(tokenFrom, spender, amountFrom);
                          }
                          // Perform the swap
                          aggregator.functionCallWithValue(
                              abi.encodePacked(method, data),
                              address(this).balance
                          );
                          // Transfer remaining balance of tokenFrom to sender
                          if (address(tokenFrom) != Constants.ETH) {
                              _transfer(tokenFrom, tokenFrom.balanceOf(address(this)), recipient);
                          } else {
                              // If using ETH, just unwrap any remaining WETH
                              // At the end of this function all ETH will be transferred to the sender
                              _unwrapWETH();
                          }
                          uint256 weiBalance = address(this).balance;
                          // Transfer remaining balance of tokenTo to sender
                          if (address(tokenTo) != Constants.ETH) {
                              uint256 balance = tokenTo.balanceOf(address(this));
                              require(balance >= amountTo, "INSUFFICIENT_AMOUNT");
                              _transfer(tokenTo, balance, recipient);
                          } else {
                              // If tokenTo == ETH, unwrap received WETH and add it to the wei balance,
                              // then check that the remaining ETH balance >= amountTo
                              // It is safe to not use safeMath as no one can have enough Ether to overflow
                              weiBalance += _unwrapWETH();
                              require(weiBalance >= amountTo, "INSUFFICIENT_AMOUNT");
                          }
                          // If there are unused fees or if tokenTo is ETH, transfer to sender
                          if (weiBalance > 0) {
                              recipient.sendValue(weiBalance);
                          }
                      }
                      /**
                       * @dev Unwraps all available WETH into ETH
                       */
                      function _unwrapWETH() internal returns (uint256) {
                          uint256 balance = weth.balanceOf(address(this));
                          weth.withdraw(balance);
                          return balance;
                      }
                      /**
                       * @dev Transfers token to sender if amount > 0
                       * @param token IERC20 token to transfer to sender
                       * @param amount Amount of token to transfer
                       * @param recipient Address that will receive the tokens
                       */
                      function _transfer(
                          IERC20 token,
                          uint256 amount,
                          address recipient
                      ) internal {
                          if (amount > 0) {
                              token.safeTransfer(recipient, amount);
                          }
                      }
                      // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/SafeERC20.sol
                      /**
                       * @dev Approves max amount of token to the spender if the allowance is lower than amount
                       * @param token The ERC20 token to approve
                       * @param spender Address to which funds will be approved
                       * @param amount Amount used to compare current allowance
                       */
                      function _approveSpender(
                          IERC20 token,
                          address spender,
                          uint256 amount
                      ) internal {
                          // If allowance is not enough, approve max possible amount
                          uint256 allowance = token.allowance(address(this), spender);
                          if (allowance < amount) {
                              bytes memory returndata = address(token).functionCall(
                                  abi.encodeWithSelector(
                                      token.approve.selector,
                                      spender,
                                      type(uint256).max
                                  )
                              );
                              if (returndata.length > 0) {
                                  // Return data is optional
                                  require(abi.decode(returndata, (bool)), "APPROVAL_FAILED");
                              }
                          }
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  interface ICHI is IERC20 {
                      function freeUpTo(uint256 value) external returns (uint256);
                      function freeFromUpTo(
                          address from,
                          uint256 value
                      ) external returns (uint256);
                      function mint(uint256 value) external;
                  }
                    
                  // SPDX-License-Identifier: UNLICENSED
                  pragma solidity ^0.6.0;
                  // We import the contract so truffle compiles it, and we have the ABI
                  // available when working from truffle console.
                  import "@openzeppelin/contracts/token/ERC20/ERC20.sol"; //helpers// SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.0;
                  import "../../GSN/Context.sol";
                  import "./IERC20.sol";
                  import "../../math/SafeMath.sol";
                  import "../../utils/Address.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 ERC20 is Context, IERC20 {
                      using SafeMath for uint256;
                      using Address for address;
                      mapping (address => uint256) private _balances;
                      mapping (address => mapping (address => uint256)) private _allowances;
                      uint256 private _totalSupply;
                      string private _name;
                      string private _symbol;
                      uint8 private _decimals;
                      /**
                       * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
                       * a default value of 18.
                       *
                       * To select a different value for {decimals}, use {_setupDecimals}.
                       *
                       * All three of these values are immutable: they can only be set once during
                       * construction.
                       */
                      constructor (string memory name, string memory symbol) public {
                          _name = name;
                          _symbol = symbol;
                          _decimals = 18;
                      }
                      /**
                       * @dev Returns the name of the token.
                       */
                      function name() public view returns (string memory) {
                          return _name;
                      }
                      /**
                       * @dev Returns the symbol of the token, usually a shorter version of the
                       * name.
                       */
                      function symbol() public view 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 {_setupDecimals} is
                       * called.
                       *
                       * 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 returns (uint8) {
                          return _decimals;
                      }
                      /**
                       * @dev See {IERC20-totalSupply}.
                       */
                      function totalSupply() public view override returns (uint256) {
                          return _totalSupply;
                      }
                      /**
                       * @dev See {IERC20-balanceOf}.
                       */
                      function balanceOf(address account) public view 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);
                          _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
                          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].add(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) {
                          _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
                          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);
                          _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
                          _balances[recipient] = _balances[recipient].add(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 = _totalSupply.add(amount);
                          _balances[account] = _balances[account].add(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);
                          _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
                          _totalSupply = _totalSupply.sub(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 Sets {decimals} to a value other than the default one of 18.
                       *
                       * WARNING: This function should only be called from the constructor. Most
                       * applications that interact with token contracts will not expect
                       * {decimals} to ever change, and may work incorrectly if it does.
                       */
                      function _setupDecimals(uint8 decimals_) internal {
                          _decimals = decimals_;
                      }
                      /**
                       * @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 { }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.0;
                  /*
                   * @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;
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/access/Ownable.sol";
                  import "@openzeppelin/contracts/utils/Pausable.sol";
                  import "@openzeppelin/contracts/utils/Address.sol";
                  import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                  import "./ICHI.sol";
                  import "./Spender.sol";
                  /**
                   * @title MetaSwap
                   */
                  contract MetaSwap is Ownable, Pausable, ReentrancyGuard {
                      using SafeERC20 for IERC20;
                      using Address for address;
                      using Address for address payable;
                      struct Adapter {
                          address addr; // adapter's address
                          bytes4 selector;
                          bytes data; // adapter's fixed data
                      }
                      ICHI public immutable chi;
                      Spender public immutable spender;
                      // Mapping of aggregatorId to aggregator
                      mapping(string => Adapter) public adapters;
                      mapping(string => bool) public adapterRemoved;
                      event AdapterSet(
                          string indexed aggregatorId,
                          address indexed addr,
                          bytes4 selector,
                          bytes data
                      );
                      event AdapterRemoved(string indexed aggregatorId);
                      event Swap(string indexed aggregatorId, address indexed sender);
                      constructor(ICHI _chi) public {
                          chi = _chi;
                          spender = new Spender();
                      }
                      /**
                       * @dev Sets the adapter for an aggregator. It can't be changed later.
                       * @param aggregatorId Aggregator's identifier
                       * @param addr Address of the contract that contains the logic for this aggregator
                       * @param selector The function selector of the swap function in the adapter
                       * @param data Fixed abi encoded data the will be passed in each delegatecall made to the adapter
                       */
                      function setAdapter(
                          string calldata aggregatorId,
                          address addr,
                          bytes4 selector,
                          bytes calldata data
                      ) external onlyOwner {
                          require(addr.isContract(), "ADAPTER_IS_NOT_A_CONTRACT");
                          require(!adapterRemoved[aggregatorId], "ADAPTER_REMOVED");
                          Adapter storage adapter = adapters[aggregatorId];
                          require(adapter.addr == address(0), "ADAPTER_EXISTS");
                          adapter.addr = addr;
                          adapter.selector = selector;
                          adapter.data = data;
                          emit AdapterSet(aggregatorId, addr, selector, data);
                      }
                      /**
                       * @dev Removes the adapter for an existing aggregator. This can't be undone.
                       * @param aggregatorId Aggregator's identifier
                       */
                      function removeAdapter(string calldata aggregatorId) external onlyOwner {
                          require(
                              adapters[aggregatorId].addr != address(0),
                              "ADAPTER_DOES_NOT_EXIST"
                          );
                          delete adapters[aggregatorId];
                          adapterRemoved[aggregatorId] = true;
                          emit AdapterRemoved(aggregatorId);
                      }
                      /**
                       * @dev Performs a swap
                       * @param aggregatorId Identifier of the aggregator to be used for the swap
                       * @param data Dynamic data which is concatenated with the fixed aggregator's
                       * data in the delecatecall made to the adapter
                       */
                      function swap(
                          string calldata aggregatorId,
                          IERC20 tokenFrom,
                          uint256 amount,
                          bytes calldata data
                      ) external payable whenNotPaused nonReentrant {
                          _swap(aggregatorId, tokenFrom, amount, data);
                      }
                      /**
                       * @dev Performs a swap
                       * @param aggregatorId Identifier of the aggregator to be used for the swap
                       * @param data Dynamic data which is concatenated with the fixed aggregator's
                       * data in the delecatecall made to the adapter
                       */
                      function swapUsingGasToken(
                          string calldata aggregatorId,
                          IERC20 tokenFrom,
                          uint256 amount,
                          bytes calldata data
                      ) external payable whenNotPaused nonReentrant {
                          uint256 gas = gasleft();
                          _swap(aggregatorId, tokenFrom, amount, data);
                          uint256 gasSpent = 21000 + gas - gasleft() + 16 * msg.data.length;
                          chi.freeFromUpTo(msg.sender, (gasSpent + 14154) / 41947);
                      }
                      function pauseSwaps() external onlyOwner {
                          _pause();
                      }
                      function unpauseSwaps() external onlyOwner {
                          _unpause();
                      }
                      function _swap(
                          string calldata aggregatorId,
                          IERC20 tokenFrom,
                          uint256 amount,
                          bytes calldata data
                      ) internal {
                          Adapter storage adapter = adapters[aggregatorId];
                          if (address(tokenFrom) != Constants.ETH) {
                              tokenFrom.safeTransferFrom(msg.sender, address(spender), amount);
                          }
                          spender.swap{value: msg.value}(
                              adapter.addr,
                              abi.encodePacked(
                                  adapter.selector,
                                  abi.encode(msg.sender),
                                  adapter.data,
                                  data
                              )
                          );
                          emit Swap(aggregatorId, msg.sender);
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.0;
                  import "../GSN/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.
                   */
                  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 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;
                  import "../GSN/Context.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.
                   */
                  contract Pausable is Context {
                      /**
                       * @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.
                       */
                      constructor () internal {
                          _paused = false;
                      }
                      /**
                       * @dev Returns true if the contract is paused, and false otherwise.
                       */
                      function paused() public view 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());
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.0;
                  /**
                   * @dev Contract module that helps prevent reentrant calls to a function.
                   *
                   * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
                   * available, which can be applied to functions to make sure there are no nested
                   * (reentrant) calls to them.
                   *
                   * Note that because there is a single `nonReentrant` guard, functions marked as
                   * `nonReentrant` may not call one another. This can be worked around by making
                   * those functions `private`, and then adding `external` `nonReentrant` entry
                   * points to them.
                   *
                   * TIP: If you would like to learn more about reentrancy and alternative ways
                   * to protect against it, check out our blog post
                   * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
                   */
                  contract ReentrancyGuard {
                      // Booleans are more expensive than uint256 or any type that takes up a full
                      // word because each write operation emits an extra SLOAD to first read the
                      // slot's contents, replace the bits taken up by the boolean, and then write
                      // back. This is the compiler's defense against contract upgrades and
                      // pointer aliasing, and it cannot be disabled.
                      // The values being non-zero value makes deployment a bit more expensive,
                      // but in exchange the refund on every call to nonReentrant will be lower in
                      // amount. Since refunds are capped to a percentage of the total
                      // transaction's gas, it is best to keep them low in cases like this one, to
                      // increase the likelihood of the full refund coming into effect.
                      uint256 private constant _NOT_ENTERED = 1;
                      uint256 private constant _ENTERED = 2;
                      uint256 private _status;
                      constructor () internal {
                          _status = _NOT_ENTERED;
                      }
                      /**
                       * @dev Prevents a contract from calling itself, directly or indirectly.
                       * Calling a `nonReentrant` function from another `nonReentrant`
                       * function is not supported. It is possible to prevent this from happening
                       * by making the `nonReentrant` function external, and make it call a
                       * `private` function that does the actual work.
                       */
                      modifier nonReentrant() {
                          // On the first call to nonReentrant, _notEntered will be true
                          require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
                          // Any calls to nonReentrant after this point will fail
                          _status = _ENTERED;
                          _;
                          // By storing the original value once again, a refund is triggered (see
                          // https://eips.ethereum.org/EIPS/eip-2200)
                          _status = _NOT_ENTERED;
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.6.0;
                  import "./Constants.sol";
                  contract Spender {
                      address public immutable metaswap;
                      constructor() public {
                          metaswap = msg.sender;
                      }
                      /// @dev Receives ether from swaps
                      fallback() external payable {}
                      function swap(address adapter, bytes calldata data) external payable {
                          require(msg.sender == metaswap, "FORBIDDEN");
                          require(adapter != address(0), "ADAPTER_NOT_PROVIDED");
                          _delegate(adapter, data, "ADAPTER_DELEGATECALL_FAILED");
                      }
                      /**
                       * @dev Performs a delegatecall and bubbles up the errors, adapted from
                       * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Address.sol
                       * @param target Address of the contract to delegatecall
                       * @param data Data passed in the delegatecall
                       * @param errorMessage Fallback revert reason
                       */
                      function _delegate(
                          address target,
                          bytes memory data,
                          string memory errorMessage
                      ) private returns (bytes memory) {
                          // solhint-disable-next-line avoid-low-level-calls
                          (bool success, bytes memory returndata) = target.delegatecall(data);
                          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);
                              }
                          }
                      }
                  }
                  pragma solidity ^0.6.0;
                  import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
                  import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
                  import "@openzeppelin/contracts/utils/Address.sol";
                  contract MockAdapter {
                      using SafeERC20 for IERC20;
                      using Address for address;
                      using Address for address payable;
                      event MockAdapterEvent(
                          address sender,
                          uint256 valueFixed,
                          uint256 valueDynamic
                      );
                      function test(
                          address sender,
                          uint256 valueFixed,
                          uint256 valueDynamic
                      ) external payable {
                          emit MockAdapterEvent(sender, valueFixed, valueDynamic);
                      }
                      function testRevert(
                          address,
                          uint256,
                          uint256
                      ) external payable {
                          revert("SWAP_FAILED");
                      }
                      function testRevertNoReturnData(
                          address,
                          uint256,
                          uint256
                      ) external payable {
                          revert();
                      }
                  }
                  pragma solidity ^0.6.0;
                  // TAKEN FROM https://github.com/gnosis/mock-contract
                  // TODO: use their npm package once it is published for solidity 0.6
                  interface MockInterface {
                      /**
                       * @dev After calling this method, the mock will return `response` when it is called
                       * with any calldata that is not mocked more specifically below
                       * (e.g. using givenMethodReturn).
                       * @param response ABI encoded response that will be returned if method is invoked
                       */
                      function givenAnyReturn(bytes calldata response) external;
                      function givenAnyReturnBool(bool response) external;
                      function givenAnyReturnUint(uint256 response) external;
                      function givenAnyReturnAddress(address response) external;
                      function givenAnyRevert() external;
                      function givenAnyRevertWithMessage(string calldata message) external;
                      function givenAnyRunOutOfGas() external;
                      /**
                       * @dev After calling this method, the mock will return `response` when the given
                       * methodId is called regardless of arguments. If the methodId and arguments
                       * are mocked more specifically (using `givenMethodAndArguments`) the latter
                       * will take precedence.
                       * @param method ABI encoded methodId. It is valid to pass full calldata (including arguments). The mock will extract the methodId from it
                       * @param response ABI encoded response that will be returned if method is invoked
                       */
                      function givenMethodReturn(bytes calldata method, bytes calldata response)
                          external;
                      function givenMethodReturnBool(bytes calldata method, bool response)
                          external;
                      function givenMethodReturnUint(bytes calldata method, uint256 response)
                          external;
                      function givenMethodReturnAddress(bytes calldata method, address response)
                          external;
                      function givenMethodRevert(bytes calldata method) external;
                      function givenMethodRevertWithMessage(
                          bytes calldata method,
                          string calldata message
                      ) external;
                      function givenMethodRunOutOfGas(bytes calldata method) external;
                      /**
                       * @dev After calling this method, the mock will return `response` when the given
                       * methodId is called with matching arguments. These exact calldataMocks will take
                       * precedence over all other calldataMocks.
                       * @param call ABI encoded calldata (methodId and arguments)
                       * @param response ABI encoded response that will be returned if contract is invoked with calldata
                       */
                      function givenCalldataReturn(bytes calldata call, bytes calldata response)
                          external;
                      function givenCalldataReturnBool(bytes calldata call, bool response)
                          external;
                      function givenCalldataReturnUint(bytes calldata call, uint256 response)
                          external;
                      function givenCalldataReturnAddress(bytes calldata call, address response)
                          external;
                      function givenCalldataRevert(bytes calldata call) external;
                      function givenCalldataRevertWithMessage(
                          bytes calldata call,
                          string calldata message
                      ) external;
                      function givenCalldataRunOutOfGas(bytes calldata call) external;
                      /**
                       * @dev Returns the number of times anything has been called on this mock since last reset
                       */
                      function invocationCount() external returns (uint256);
                      /**
                       * @dev Returns the number of times the given method has been called on this mock since last reset
                       * @param method ABI encoded methodId. It is valid to pass full calldata (including arguments). The mock will extract the methodId from it
                       */
                      function invocationCountForMethod(bytes calldata method)
                          external
                          returns (uint256);
                      /**
                       * @dev Returns the number of times this mock has been called with the exact calldata since last reset.
                       * @param call ABI encoded calldata (methodId and arguments)
                       */
                      function invocationCountForCalldata(bytes calldata call)
                          external
                          returns (uint256);
                      /**
                       * @dev Resets all mocked methods and invocation counts.
                       */
                      function reset() external;
                  }
                  /**
                   * Implementation of the MockInterface.
                   */
                  contract MockContract is MockInterface {
                      enum MockType {Return, Revert, OutOfGas}
                      bytes32 public constant MOCKS_LIST_START = hex"01";
                      bytes public constant MOCKS_LIST_END = "0xff";
                      bytes32 public constant MOCKS_LIST_END_HASH = keccak256(MOCKS_LIST_END);
                      bytes4 public constant SENTINEL_ANY_MOCKS = hex"01";
                      bytes public constant DEFAULT_FALLBACK_VALUE = abi.encode(false);
                      // A linked list allows easy iteration and inclusion checks
                      mapping(bytes32 => bytes) calldataMocks;
                      mapping(bytes => MockType) calldataMockTypes;
                      mapping(bytes => bytes) calldataExpectations;
                      mapping(bytes => string) calldataRevertMessage;
                      mapping(bytes32 => uint256) calldataInvocations;
                      mapping(bytes4 => bytes4) methodIdMocks;
                      mapping(bytes4 => MockType) methodIdMockTypes;
                      mapping(bytes4 => bytes) methodIdExpectations;
                      mapping(bytes4 => string) methodIdRevertMessages;
                      mapping(bytes32 => uint256) methodIdInvocations;
                      MockType fallbackMockType;
                      bytes fallbackExpectation = DEFAULT_FALLBACK_VALUE;
                      string fallbackRevertMessage;
                      uint256 invocations;
                      uint256 resetCount;
                      constructor() public {
                          calldataMocks[MOCKS_LIST_START] = MOCKS_LIST_END;
                          methodIdMocks[SENTINEL_ANY_MOCKS] = SENTINEL_ANY_MOCKS;
                      }
                      function trackCalldataMock(bytes memory call) private {
                          bytes32 callHash = keccak256(call);
                          if (calldataMocks[callHash].length == 0) {
                              calldataMocks[callHash] = calldataMocks[MOCKS_LIST_START];
                              calldataMocks[MOCKS_LIST_START] = call;
                          }
                      }
                      function trackMethodIdMock(bytes4 methodId) private {
                          if (methodIdMocks[methodId] == 0x0) {
                              methodIdMocks[methodId] = methodIdMocks[SENTINEL_ANY_MOCKS];
                              methodIdMocks[SENTINEL_ANY_MOCKS] = methodId;
                          }
                      }
                      function _givenAnyReturn(bytes memory response) internal {
                          fallbackMockType = MockType.Return;
                          fallbackExpectation = response;
                      }
                      function givenAnyReturn(bytes calldata response) external override {
                          _givenAnyReturn(response);
                      }
                      function givenAnyReturnBool(bool response) external override {
                          uint256 flag = response ? 1 : 0;
                          _givenAnyReturn(uintToBytes(flag));
                      }
                      function givenAnyReturnUint(uint256 response) external override {
                          _givenAnyReturn(uintToBytes(response));
                      }
                      function givenAnyReturnAddress(address response) external override {
                          _givenAnyReturn(uintToBytes(uint256(response)));
                      }
                      function givenAnyRevert() external override {
                          fallbackMockType = MockType.Revert;
                          fallbackRevertMessage = "";
                      }
                      function givenAnyRevertWithMessage(string calldata message)
                          external
                          override
                      {
                          fallbackMockType = MockType.Revert;
                          fallbackRevertMessage = message;
                      }
                      function givenAnyRunOutOfGas() external override {
                          fallbackMockType = MockType.OutOfGas;
                      }
                      function _givenCalldataReturn(bytes memory call, bytes memory response)
                          private
                      {
                          calldataMockTypes[call] = MockType.Return;
                          calldataExpectations[call] = response;
                          trackCalldataMock(call);
                      }
                      function givenCalldataReturn(bytes calldata call, bytes calldata response)
                          external
                          override
                      {
                          _givenCalldataReturn(call, response);
                      }
                      function givenCalldataReturnBool(bytes calldata call, bool response)
                          external
                          override
                      {
                          uint256 flag = response ? 1 : 0;
                          _givenCalldataReturn(call, uintToBytes(flag));
                      }
                      function givenCalldataReturnUint(bytes calldata call, uint256 response)
                          external
                          override
                      {
                          _givenCalldataReturn(call, uintToBytes(response));
                      }
                      function givenCalldataReturnAddress(bytes calldata call, address response)
                          external
                          override
                      {
                          _givenCalldataReturn(call, uintToBytes(uint256(response)));
                      }
                      function _givenMethodReturn(bytes memory call, bytes memory response)
                          private
                      {
                          bytes4 method = bytesToBytes4(call);
                          methodIdMockTypes[method] = MockType.Return;
                          methodIdExpectations[method] = response;
                          trackMethodIdMock(method);
                      }
                      function givenMethodReturn(bytes calldata call, bytes calldata response)
                          external
                          override
                      {
                          _givenMethodReturn(call, response);
                      }
                      function givenMethodReturnBool(bytes calldata call, bool response)
                          external
                          override
                      {
                          uint256 flag = response ? 1 : 0;
                          _givenMethodReturn(call, uintToBytes(flag));
                      }
                      function givenMethodReturnUint(bytes calldata call, uint256 response)
                          external
                          override
                      {
                          _givenMethodReturn(call, uintToBytes(response));
                      }
                      function givenMethodReturnAddress(bytes calldata call, address response)
                          external
                          override
                      {
                          _givenMethodReturn(call, uintToBytes(uint256(response)));
                      }
                      function givenCalldataRevert(bytes calldata call) external override {
                          calldataMockTypes[call] = MockType.Revert;
                          calldataRevertMessage[call] = "";
                          trackCalldataMock(call);
                      }
                      function givenMethodRevert(bytes calldata call) external override {
                          bytes4 method = bytesToBytes4(call);
                          methodIdMockTypes[method] = MockType.Revert;
                          trackMethodIdMock(method);
                      }
                      function givenCalldataRevertWithMessage(
                          bytes calldata call,
                          string calldata message
                      ) external override {
                          calldataMockTypes[call] = MockType.Revert;
                          calldataRevertMessage[call] = message;
                          trackCalldataMock(call);
                      }
                      function givenMethodRevertWithMessage(
                          bytes calldata call,
                          string calldata message
                      ) external override {
                          bytes4 method = bytesToBytes4(call);
                          methodIdMockTypes[method] = MockType.Revert;
                          methodIdRevertMessages[method] = message;
                          trackMethodIdMock(method);
                      }
                      function givenCalldataRunOutOfGas(bytes calldata call) external override {
                          calldataMockTypes[call] = MockType.OutOfGas;
                          trackCalldataMock(call);
                      }
                      function givenMethodRunOutOfGas(bytes calldata call) external override {
                          bytes4 method = bytesToBytes4(call);
                          methodIdMockTypes[method] = MockType.OutOfGas;
                          trackMethodIdMock(method);
                      }
                      function invocationCount() external override returns (uint256) {
                          return invocations;
                      }
                      function invocationCountForMethod(bytes calldata call)
                          external
                          override
                          returns (uint256)
                      {
                          bytes4 method = bytesToBytes4(call);
                          return
                              methodIdInvocations[keccak256(
                                  abi.encodePacked(resetCount, method)
                              )];
                      }
                      function invocationCountForCalldata(bytes calldata call)
                          external
                          override
                          returns (uint256)
                      {
                          return
                              calldataInvocations[keccak256(abi.encodePacked(resetCount, call))];
                      }
                      function reset() external override {
                          // Reset all exact calldataMocks
                          bytes memory nextMock = calldataMocks[MOCKS_LIST_START];
                          bytes32 mockHash = keccak256(nextMock);
                          // We cannot compary bytes
                          while (mockHash != MOCKS_LIST_END_HASH) {
                              // Reset all mock maps
                              calldataMockTypes[nextMock] = MockType.Return;
                              calldataExpectations[nextMock] = hex"";
                              calldataRevertMessage[nextMock] = "";
                              // Set next mock to remove
                              nextMock = calldataMocks[mockHash];
                              // Remove from linked list
                              calldataMocks[mockHash] = "";
                              // Update mock hash
                              mockHash = keccak256(nextMock);
                          }
                          // Clear list
                          calldataMocks[MOCKS_LIST_START] = MOCKS_LIST_END;
                          // Reset all any calldataMocks
                          bytes4 nextAnyMock = methodIdMocks[SENTINEL_ANY_MOCKS];
                          while (nextAnyMock != SENTINEL_ANY_MOCKS) {
                              bytes4 currentAnyMock = nextAnyMock;
                              methodIdMockTypes[currentAnyMock] = MockType.Return;
                              methodIdExpectations[currentAnyMock] = hex"";
                              methodIdRevertMessages[currentAnyMock] = "";
                              nextAnyMock = methodIdMocks[currentAnyMock];
                              // Remove from linked list
                              methodIdMocks[currentAnyMock] = 0x0;
                          }
                          // Clear list
                          methodIdMocks[SENTINEL_ANY_MOCKS] = SENTINEL_ANY_MOCKS;
                          fallbackExpectation = DEFAULT_FALLBACK_VALUE;
                          fallbackMockType = MockType.Return;
                          invocations = 0;
                          resetCount += 1;
                      }
                      function useAllGas() private {
                          while (true) {
                              bool s;
                              assembly {
                                  //expensive call to EC multiply contract
                                  s := call(sub(gas(), 2000), 6, 0, 0x0, 0xc0, 0x0, 0x60)
                              }
                          }
                      }
                      function bytesToBytes4(bytes memory b) private pure returns (bytes4) {
                          bytes4 out;
                          for (uint256 i = 0; i < 4; i++) {
                              out |= bytes4(b[i] & 0xFF) >> (i * 8);
                          }
                          return out;
                      }
                      function uintToBytes(uint256 x) private pure returns (bytes memory b) {
                          b = new bytes(32);
                          assembly {
                              mstore(add(b, 32), x)
                          }
                      }
                      function updateInvocationCount(
                          bytes4 methodId,
                          bytes memory originalMsgData
                      ) public {
                          require(
                              msg.sender == address(this),
                              "Can only be called from the contract itself"
                          );
                          invocations += 1;
                          methodIdInvocations[keccak256(
                              abi.encodePacked(resetCount, methodId)
                          )] += 1;
                          calldataInvocations[keccak256(
                              abi.encodePacked(resetCount, originalMsgData)
                          )] += 1;
                      }
                      fallback() external payable {
                          bytes4 methodId;
                          assembly {
                              methodId := calldataload(0)
                          }
                          // First, check exact matching overrides
                          if (calldataMockTypes[msg.data] == MockType.Revert) {
                              revert(calldataRevertMessage[msg.data]);
                          }
                          if (calldataMockTypes[msg.data] == MockType.OutOfGas) {
                              useAllGas();
                          }
                          bytes memory result = calldataExpectations[msg.data];
                          // Then check method Id overrides
                          if (result.length == 0) {
                              if (methodIdMockTypes[methodId] == MockType.Revert) {
                                  revert(methodIdRevertMessages[methodId]);
                              }
                              if (methodIdMockTypes[methodId] == MockType.OutOfGas) {
                                  useAllGas();
                              }
                              result = methodIdExpectations[methodId];
                          }
                          // Last, use the fallback override
                          if (result.length == 0) {
                              if (fallbackMockType == MockType.Revert) {
                                  revert(fallbackRevertMessage);
                              }
                              if (fallbackMockType == MockType.OutOfGas) {
                                  useAllGas();
                              }
                              result = fallbackExpectation;
                          }
                          // Record invocation as separate call so we don't rollback in case we are called with STATICCALL
                          (, bytes memory r) = address(this).call{gas: 100000}(
                              abi.encodeWithSignature(
                                  "updateInvocationCount(bytes4,bytes)",
                                  methodId,
                                  msg.data
                              )
                          );
                          assert(r.length == 0);
                          assembly {
                              return(add(0x20, result), mload(result))
                          }
                      }
                  }
                  pragma solidity ^0.6.0;
                  contract MockSelfDestruct {
                      constructor() public payable {}
                      fallback() external payable {
                          selfdestruct(msg.sender);
                      }
                      function kill(address payable target) external payable {
                          selfdestruct(target);
                      }
                  }
                  

                  File 2 of 9: DexRouter
                  // SPDX-License-Identifier: MIT
                  // OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)
                  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 onlyInitializing {
                          __Ownable_init_unchained();
                      }
                      function __Ownable_init_unchained() internal onlyInitializing {
                          _transferOwnership(_msgSender());
                      }
                      /**
                       * @dev Throws if called by any account other than the owner.
                       */
                      modifier onlyOwner() {
                          _checkOwner();
                          _;
                      }
                      /**
                       * @dev Returns the address of the current owner.
                       */
                      function owner() public view virtual returns (address) {
                          return _owner;
                      }
                      /**
                       * @dev Throws if the sender is not the owner.
                       */
                      function _checkOwner() internal view virtual {
                          require(owner() == _msgSender(), "Ownable: caller is not the owner");
                      }
                      /**
                       * @dev Leaves the contract without owner. It will not be possible to call
                       * `onlyOwner` functions. Can only be called by the current owner.
                       *
                       * NOTE: Renouncing ownership will leave the contract without an owner,
                       * thereby disabling any functionality that is only available to the owner.
                       */
                      function renounceOwnership() public virtual onlyOwner {
                          _transferOwnership(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");
                          _transferOwnership(newOwner);
                      }
                      /**
                       * @dev Transfers ownership of the contract to a new account (`newOwner`).
                       * Internal function without access restriction.
                       */
                      function _transferOwnership(address newOwner) internal virtual {
                          address oldOwner = _owner;
                          _owner = newOwner;
                          emit OwnershipTransferred(oldOwner, newOwner);
                      }
                      /**
                       * @dev This empty reserved space is put in place to allow future versions to add new
                       * variables without shifting down storage in the inheritance chain.
                       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
                       */
                      uint256[49] private __gap;
                  }
                  // SPDX-License-Identifier: MIT
                  // OpenZeppelin Contracts (last updated v4.9.0) (proxy/utils/Initializable.sol)
                  pragma solidity ^0.8.2;
                  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 proxied contracts do not make use of 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.
                   *
                   * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
                   * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
                   * case an upgrade adds a module that needs to be initialized.
                   *
                   * For example:
                   *
                   * [.hljs-theme-light.nopadding]
                   * ```solidity
                   * contract MyToken is ERC20Upgradeable {
                   *     function initialize() initializer public {
                   *         __ERC20_init("MyToken", "MTK");
                   *     }
                   * }
                   *
                   * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
                   *     function initializeV2() reinitializer(2) public {
                   *         __ERC20Permit_init("MyToken");
                   *     }
                   * }
                   * ```
                   *
                   * 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 {ERC1967Proxy-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.
                   *
                   * [CAUTION]
                   * ====
                   * Avoid leaving a contract uninitialized.
                   *
                   * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
                   * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
                   * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
                   *
                   * [.hljs-theme-light.nopadding]
                   * ```
                   * /// @custom:oz-upgrades-unsafe-allow constructor
                   * constructor() {
                   *     _disableInitializers();
                   * }
                   * ```
                   * ====
                   */
                  abstract contract Initializable {
                      /**
                       * @dev Indicates that the contract has been initialized.
                       * @custom:oz-retyped-from bool
                       */
                      uint8 private _initialized;
                      /**
                       * @dev Indicates that the contract is in the process of being initialized.
                       */
                      bool private _initializing;
                      /**
                       * @dev Triggered when the contract has been initialized or reinitialized.
                       */
                      event Initialized(uint8 version);
                      /**
                       * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
                       * `onlyInitializing` functions can be used to initialize parent contracts.
                       *
                       * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
                       * constructor.
                       *
                       * Emits an {Initialized} event.
                       */
                      modifier initializer() {
                          bool isTopLevelCall = !_initializing;
                          require(
                              (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
                              "Initializable: contract is already initialized"
                          );
                          _initialized = 1;
                          if (isTopLevelCall) {
                              _initializing = true;
                          }
                          _;
                          if (isTopLevelCall) {
                              _initializing = false;
                              emit Initialized(1);
                          }
                      }
                      /**
                       * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
                       * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
                       * used to initialize parent contracts.
                       *
                       * A reinitializer may be used after the original initialization step. This is essential to configure modules that
                       * are added through upgrades and that require initialization.
                       *
                       * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
                       * cannot be nested. If one is invoked in the context of another, execution will revert.
                       *
                       * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
                       * a contract, executing them in the right order is up to the developer or operator.
                       *
                       * WARNING: setting the version to 255 will prevent any future reinitialization.
                       *
                       * Emits an {Initialized} event.
                       */
                      modifier reinitializer(uint8 version) {
                          require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
                          _initialized = version;
                          _initializing = true;
                          _;
                          _initializing = false;
                          emit Initialized(version);
                      }
                      /**
                       * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
                       * {initializer} and {reinitializer} modifiers, directly or indirectly.
                       */
                      modifier onlyInitializing() {
                          require(_initializing, "Initializable: contract is not initializing");
                          _;
                      }
                      /**
                       * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
                       * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
                       * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
                       * through proxies.
                       *
                       * Emits an {Initialized} event the first time it is successfully executed.
                       */
                      function _disableInitializers() internal virtual {
                          require(!_initializing, "Initializable: contract is initializing");
                          if (_initialized != type(uint8).max) {
                              _initialized = type(uint8).max;
                              emit Initialized(type(uint8).max);
                          }
                      }
                      /**
                       * @dev Returns the highest version that has been initialized. See {reinitializer}.
                       */
                      function _getInitializedVersion() internal view returns (uint8) {
                          return _initialized;
                      }
                      /**
                       * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
                       */
                      function _isInitializing() internal view returns (bool) {
                          return _initializing;
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  // OpenZeppelin Contracts (last updated v4.9.0) (security/ReentrancyGuard.sol)
                  pragma solidity ^0.8.0;
                  import "../proxy/utils/Initializable.sol";
                  /**
                   * @dev Contract module that helps prevent reentrant calls to a function.
                   *
                   * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
                   * available, which can be applied to functions to make sure there are no nested
                   * (reentrant) calls to them.
                   *
                   * Note that because there is a single `nonReentrant` guard, functions marked as
                   * `nonReentrant` may not call one another. This can be worked around by making
                   * those functions `private`, and then adding `external` `nonReentrant` entry
                   * points to them.
                   *
                   * TIP: If you would like to learn more about reentrancy and alternative ways
                   * to protect against it, check out our blog post
                   * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
                   */
                  abstract contract ReentrancyGuardUpgradeable is Initializable {
                      // Booleans are more expensive than uint256 or any type that takes up a full
                      // word because each write operation emits an extra SLOAD to first read the
                      // slot's contents, replace the bits taken up by the boolean, and then write
                      // back. This is the compiler's defense against contract upgrades and
                      // pointer aliasing, and it cannot be disabled.
                      // The values being non-zero value makes deployment a bit more expensive,
                      // but in exchange the refund on every call to nonReentrant will be lower in
                      // amount. Since refunds are capped to a percentage of the total
                      // transaction's gas, it is best to keep them low in cases like this one, to
                      // increase the likelihood of the full refund coming into effect.
                      uint256 private constant _NOT_ENTERED = 1;
                      uint256 private constant _ENTERED = 2;
                      uint256 private _status;
                      function __ReentrancyGuard_init() internal onlyInitializing {
                          __ReentrancyGuard_init_unchained();
                      }
                      function __ReentrancyGuard_init_unchained() internal onlyInitializing {
                          _status = _NOT_ENTERED;
                      }
                      /**
                       * @dev Prevents a contract from calling itself, directly or indirectly.
                       * Calling a `nonReentrant` function from another `nonReentrant`
                       * function is not supported. It is possible to prevent this from happening
                       * by making the `nonReentrant` function external, and making it call a
                       * `private` function that does the actual work.
                       */
                      modifier nonReentrant() {
                          _nonReentrantBefore();
                          _;
                          _nonReentrantAfter();
                      }
                      function _nonReentrantBefore() private {
                          // On the first call to nonReentrant, _status will be _NOT_ENTERED
                          require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
                          // Any calls to nonReentrant after this point will fail
                          _status = _ENTERED;
                      }
                      function _nonReentrantAfter() private {
                          // By storing the original value once again, a refund is triggered (see
                          // https://eips.ethereum.org/EIPS/eip-2200)
                          _status = _NOT_ENTERED;
                      }
                      /**
                       * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
                       * `nonReentrant` function in the call stack.
                       */
                      function _reentrancyGuardEntered() internal view returns (bool) {
                          return _status == _ENTERED;
                      }
                      /**
                       * @dev This empty reserved space is put in place to allow future versions to add new
                       * variables without shifting down storage in the inheritance chain.
                       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
                       */
                      uint256[49] private __gap;
                  }
                  // SPDX-License-Identifier: MIT
                  // OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)
                  pragma solidity ^0.8.1;
                  /**
                   * @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
                       *
                       * Furthermore, `isContract` will also return true if the target contract within
                       * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
                       * which only has an effect at the end of a transaction.
                       * ====
                       *
                       * [IMPORTANT]
                       * ====
                       * You shouldn't rely on `isContract` to protect against flash loan attacks!
                       *
                       * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
                       * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
                       * constructor.
                       * ====
                       */
                      function isContract(address account) internal view returns (bool) {
                          // This method relies on extcodesize/address.code.length, which returns 0
                          // for contracts in construction, since the code is only stored at the end
                          // of the constructor execution.
                          return account.code.length > 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://consensys.net/diligence/blog/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/v0.8.0/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");
                          (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 functionCallWithValue(target, data, 0, "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");
                          (bool success, bytes memory returndata) = target.call{value: value}(data);
                          return verifyCallResultFromTarget(target, 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) {
                          (bool success, bytes memory returndata) = target.staticcall(data);
                          return verifyCallResultFromTarget(target, 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) {
                          (bool success, bytes memory returndata) = target.delegatecall(data);
                          return verifyCallResultFromTarget(target, success, returndata, errorMessage);
                      }
                      /**
                       * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
                       * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
                       *
                       * _Available since v4.8._
                       */
                      function verifyCallResultFromTarget(
                          address target,
                          bool success,
                          bytes memory returndata,
                          string memory errorMessage
                      ) internal view returns (bytes memory) {
                          if (success) {
                              if (returndata.length == 0) {
                                  // only check isContract if the call was successful and the return data is empty
                                  // otherwise we already know that it was a contract
                                  require(isContract(target), "Address: call to non-contract");
                              }
                              return returndata;
                          } else {
                              _revert(returndata, errorMessage);
                          }
                      }
                      /**
                       * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
                       * revert reason or using the provided one.
                       *
                       * _Available since v4.3._
                       */
                      function verifyCallResult(
                          bool success,
                          bytes memory returndata,
                          string memory errorMessage
                      ) internal pure returns (bytes memory) {
                          if (success) {
                              return returndata;
                          } else {
                              _revert(returndata, errorMessage);
                          }
                      }
                      function _revert(bytes memory returndata, string memory errorMessage) private pure {
                          // 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
                              /// @solidity memory-safe-assembly
                              assembly {
                                  let returndata_size := mload(returndata)
                                  revert(add(32, returndata), returndata_size)
                              }
                          } else {
                              revert(errorMessage);
                          }
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  // OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
                  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 onlyInitializing {
                      }
                      function __Context_init_unchained() internal onlyInitializing {
                      }
                      function _msgSender() internal view virtual returns (address) {
                          return msg.sender;
                      }
                      function _msgData() internal view virtual returns (bytes calldata) {
                          return msg.data;
                      }
                      /**
                       * @dev This empty reserved space is put in place to allow future versions to add new
                       * variables without shifting down storage in the inheritance chain.
                       * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
                       */
                      uint256[50] private __gap;
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  pragma abicoder v2;
                  import "@openzeppelin/contracts-upgradeable/access/OwnableUpgradeable.sol";
                  import "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";
                  import "./UnxswapRouter.sol";
                  import "./UnxswapV3Router.sol";
                  import "./interfaces/IWETH.sol";
                  import "./interfaces/IAdapter.sol";
                  import "./interfaces/IApproveProxy.sol";
                  import "./interfaces/IWNativeRelayer.sol";
                  import "./interfaces/IXBridge.sol";
                  import "./libraries/Permitable.sol";
                  import "./libraries/PMMLib.sol";
                  import "./libraries/CommissionLib.sol";
                  import "./libraries/EthReceiver.sol";
                  import "./libraries/WrapETHSwap.sol";
                  import "./libraries/CommonUtils.sol";
                  import "./storage/DexRouterStorage.sol";
                  /// @title DexRouterV1
                  /// @notice Entrance of Split trading in Dex platform
                  /// @dev Entrance of Split trading in Dex platform
                  contract DexRouter is
                      OwnableUpgradeable,
                      ReentrancyGuardUpgradeable,
                      Permitable,
                      EthReceiver,
                      UnxswapRouter,
                      UnxswapV3Router,
                      DexRouterStorage,
                      WrapETHSwap,
                      CommissionLib
                  {
                      using UniversalERC20 for IERC20;
                      struct BaseRequest {
                          uint256 fromToken;
                          address toToken;
                          uint256 fromTokenAmount;
                          uint256 minReturnAmount;
                          uint256 deadLine;
                      }
                      struct RouterPath {
                          address[] mixAdapters;
                          address[] assetTo;
                          uint256[] rawData;
                          bytes[] extraData;
                          uint256 fromToken;
                      }
                      /// @notice Initializes the contract with necessary setup for ownership and reentrancy protection.
                      /// @dev This function serves as a constructor for upgradeable contracts and should be called
                      /// through a proxy during the initial deployment. It initializes inherited contracts
                      /// such as `OwnableUpgradeable` and `ReentrancyGuardUpgradeable` to set up the contract's owner
                      /// and reentrancy guard.
                      function initialize() public initializer {
                          __Ownable_init();
                          __ReentrancyGuard_init();
                      }
                      //-------------------------------
                      //------- Events ----------------
                      //-------------------------------
                      /// @notice Emitted when a priority address status is updated.
                      /// @param priorityAddress The address whose priority status has been changed.
                      /// @param valid A boolean indicating the new status of the priority address.
                      /// True means the address is now considered a priority address, and false means it is not.
                      event PriorityAddressChanged(address priorityAddress, bool valid);
                      /// @notice Emitted when the admin address of the contract is changed.
                      /// @param newAdmin The address of the new admin.
                      event AdminChanged(address newAdmin);
                      //-------------------------------
                      //------- Modifier --------------
                      //-------------------------------
                      /// @notice Ensures a function is called before a specified deadline.
                      /// @param deadLine The UNIX timestamp deadline.
                      modifier isExpired(uint256 deadLine) {
                          require(deadLine >= block.timestamp, "Route: expired");
                          _;
                      }
                      /// @notice Restricts function access to addresses marked as priority.
                      /// Ensures that only addresses designated with specific privileges can execute the function.
                      modifier onlyPriorityAddress() {
                          require(priorityAddresses[msg.sender] == true, "only priority");
                          _;
                      }
                      //-------------------------------
                      //------- Internal Functions ----
                      //-------------------------------
                      /// @notice Executes multiple adapters for a transaction pair.
                      /// @param payer The address of the payer.
                      /// @param to The address of the receiver.
                      /// @param batchAmount The amount to be transferred in each batch.
                      /// @param path The routing path for the swap.
                      /// @param noTransfer A flag to indicate whether the token transfer should be skipped.
                      /// @dev It includes checks for the total weight of the paths and executes the swapping through the adapters.
                      function _exeForks(
                          address payer,
                          address to,
                          uint256 batchAmount,
                          RouterPath calldata path,
                          bool noTransfer
                      ) private {
                          address fromToken = _bytes32ToAddress(path.fromToken);
                          // fix post audit DRW-01: lack of check on Weights
                          uint256 totalWeight;
                          // execute multiple Adapters for a transaction pair
                          uint256 pathLength = path.mixAdapters.length;
                          for (uint256 i = 0; i < pathLength; ) {
                              bytes32 rawData = bytes32(path.rawData[i]);
                              address poolAddress;
                              bool reserves;
                              uint256 weight;
                              assembly {
                                  poolAddress := and(rawData, _ADDRESS_MASK)
                                  reserves := and(rawData, _REVERSE_MASK)
                                  weight := shr(160, and(rawData, _WEIGHT_MASK))
                              }
                              totalWeight += weight;
                              if (i == pathLength - 1) {
                                  require(
                                      totalWeight <= 10_000,
                                      "totalWeight can not exceed 10000 limit"
                                  );
                              }
                              if (!noTransfer) {
                                  uint256 _fromTokenAmount = weight == 10_000
                                      ? batchAmount
                                      : (batchAmount * weight) / 10_000;
                                  _transferInternal(
                                      payer,
                                      path.assetTo[i],
                                      fromToken,
                                      _fromTokenAmount
                                  );
                              }
                              if (reserves) {
                                  IAdapter(path.mixAdapters[i]).sellQuote(
                                      to,
                                      poolAddress,
                                      path.extraData[i]
                                  );
                              } else {
                                  IAdapter(path.mixAdapters[i]).sellBase(
                                      to,
                                      poolAddress,
                                      path.extraData[i]
                                  );
                              }
                              unchecked {
                                  ++i;
                              }
                          }
                      }
                      /// @notice Executes a series of swaps or operations defined by a set of routing paths, potentially across different protocols or pools.
                      /// @param payer The address providing the tokens for the swap.
                      /// @param receiver The address receiving the output tokens.
                      /// @param isToNative Indicates whether the final asset should be converted to the native blockchain asset (e.g., ETH).
                      /// @param batchAmount The total amount of the input token to be swapped.
                      /// @param hops An array of RouterPath structures, each defining a segment of the swap route.
                      /// @dev This function manages complex swap routes that might involve multiple hops through different liquidity pools or swapping protocols.
                      /// It iterates through the provided `hops`, executing each segment of the route in sequence.
                      function _exeHop(
                          address payer,
                          address receiver,
                          bool isToNative,
                          uint256 batchAmount,
                          RouterPath[] calldata hops
                      ) private {
                          address fromToken = _bytes32ToAddress(hops[0].fromToken);
                          bool toNext;
                          bool noTransfer;
                          // execute hop
                          uint256 hopLength = hops.length;
                          for (uint256 i = 0; i < hopLength; ) {
                              if (i > 0) {
                                  fromToken = _bytes32ToAddress(hops[i].fromToken);
                                  batchAmount = IERC20(fromToken).universalBalanceOf(
                                      address(this)
                                  );
                                  payer = address(this);
                              }
                              address to = address(this);
                              if (i == hopLength - 1 && !isToNative) {
                                  to = receiver;
                              } else if (i < hopLength - 1 && hops[i + 1].assetTo.length == 1) {
                                  to = hops[i + 1].assetTo[0];
                                  toNext = true;
                              } else {
                                  toNext = false;
                              }
                              // 3.2 execute forks
                              _exeForks(payer, to, batchAmount, hops[i], noTransfer);
                              noTransfer = toNext;
                              unchecked {
                                  ++i;
                              }
                          }
                      }
                      /// @notice Transfers tokens internally within the contract.
                      /// @param payer The address of the payer.
                      /// @param to The address of the receiver.
                      /// @param token The address of the token to be transferred.
                      /// @param amount The amount of tokens to be transferred.
                      /// @dev Handles the transfer of ERC20 tokens or native tokens within the contract.
                      function _transferInternal(
                          address payer,
                          address to,
                          address token,
                          uint256 amount
                      ) private {
                          if (payer == address(this)) {
                              SafeERC20.safeTransfer(IERC20(token), to, amount);
                          } else {
                              IApproveProxy(_APPROVE_PROXY).claimTokens(token, payer, to, amount);
                          }
                      }
                      /// @notice Transfers the specified token to the user.
                      /// @param token The address of the token to be transferred.
                      /// @param to The address of the receiver.
                      /// @dev Handles the withdrawal of tokens to the user, converting WETH to ETH if necessary.
                      function _transferTokenToUser(address token, address to) private {
                          if ((IERC20(token).isETH())) {
                              uint256 wethBal = IERC20(address(uint160(_WETH))).balanceOf(
                                  address(this)
                              );
                              if (wethBal > 0) {
                                  IWETH(address(uint160(_WETH))).transfer(
                                      _WNATIVE_RELAY,
                                      wethBal
                                  );
                                  IWNativeRelayer(_WNATIVE_RELAY).withdraw(wethBal);
                              }
                              if (to != address(this)) {
                                  uint256 ethBal = address(this).balance;
                                  if (ethBal > 0) {
                                      (bool success, ) = payable(to).call{value: ethBal}("");
                                      require(success, "transfer native token failed");
                                  }
                              }
                          } else {
                              if (to != address(this)) {
                                  uint256 bal = IERC20(token).balanceOf(address(this));
                                  if (bal > 0) {
                                      SafeERC20.safeTransfer(IERC20(token), to, bal);
                                  }
                              }
                          }
                      }
                      /// @notice Converts a uint256 value into an address.
                      /// @param param The uint256 value to be converted.
                      /// @return result The address obtained from the conversion.
                      /// @dev This function is used to extract an address from a uint256,
                      /// typically used when dealing with low-level data operations or when addresses are packed into larger data types.
                      function _bytes32ToAddress(
                          uint256 param
                      ) private pure returns (address result) {
                          assembly {
                              result := and(param, _ADDRESS_MASK)
                          }
                      }
                      /// @notice Executes a complex swap based on provided parameters and paths.
                      /// @param baseRequest Basic swap details including tokens, amounts, and deadline.
                      /// @param batchesAmount Amounts for each swap batch.
                      /// @param batches Detailed swap paths for execution.
                      /// @param payer Address providing the tokens.
                      /// @param receiver Address receiving the swapped tokens.
                      /// @return returnAmount Total received tokens from the swap.
                      function _smartSwapInternal(
                          BaseRequest memory baseRequest,
                          uint256[] memory batchesAmount,
                          RouterPath[][] calldata batches,
                          address payer,
                          address receiver
                      ) private returns (uint256 returnAmount) {
                          // 1. transfer from token in
                          BaseRequest memory _baseRequest = baseRequest;
                          require(
                              _baseRequest.fromTokenAmount > 0,
                              "Route: fromTokenAmount must be > 0"
                          );
                          address fromToken = _bytes32ToAddress(_baseRequest.fromToken);
                          returnAmount = IERC20(_baseRequest.toToken).universalBalanceOf(
                              receiver
                          );
                          // In order to deal with ETH/WETH transfer rules in a unified manner,
                          // we do not need to judge according to fromToken.
                          if (UniversalERC20.isETH(IERC20(fromToken))) {
                              IWETH(address(uint160(_WETH))).deposit{
                                  value: _baseRequest.fromTokenAmount
                              }();
                              payer = address(this);
                          }
                          // 2. check total batch amount
                          {
                              // avoid stack too deep
                              uint256 totalBatchAmount;
                              for (uint256 i = 0; i < batchesAmount.length; ) {
                                  totalBatchAmount += batchesAmount[i];
                                  unchecked {
                                      ++i;
                                  }
                              }
                              require(
                                  totalBatchAmount <= _baseRequest.fromTokenAmount,
                                  "Route: number of batches should be <= fromTokenAmount"
                              );
                          }
                          // 4. execute batch
                          // check length, fix DRW-02: LACK OF LENGTH CHECK ON BATATCHES
                          require(batchesAmount.length == batches.length, "length mismatch");
                          for (uint256 i = 0; i < batches.length; ) {
                              // execute hop, if the whole swap replacing by pmm fails, the funds will return to dexRouter
                              _exeHop(
                                  payer,
                                  receiver,
                                  IERC20(_baseRequest.toToken).isETH(),
                                  batchesAmount[i],
                                  batches[i]
                              );
                              unchecked {
                                  ++i;
                              }
                          }
                          // 5. transfer tokens to user
                          _transferTokenToUser(_baseRequest.toToken, receiver);
                          // 6. check minReturnAmount
                          returnAmount =
                              IERC20(_baseRequest.toToken).universalBalanceOf(receiver) -
                              returnAmount;
                          require(
                              returnAmount >= _baseRequest.minReturnAmount,
                              "Min return not reached"
                          );
                          emit OrderRecord(
                              fromToken,
                              _baseRequest.toToken,
                              tx.origin,
                              _baseRequest.fromTokenAmount,
                              returnAmount
                          );
                          return returnAmount;
                      }
                      //-------------------------------
                      //------- Admin functions -------
                      //-------------------------------
                      /// @notice Updates the priority status of an address, allowing or disallowing it from performing certain actions.
                      /// @param _priorityAddress The address whose priority status is to be updated.
                      /// @param valid A boolean indicating whether the address should be marked as a priority (true) or not (false).
                      /// @dev This function can only be called by the contract owner or another authorized entity.
                      /// It is typically used to grant or revoke special permissions to certain addresses.
                      function setPriorityAddress(address _priorityAddress, bool valid) external {
                          require(msg.sender == admin || msg.sender == owner(), "na");
                          priorityAddresses[_priorityAddress] = valid;
                          emit PriorityAddressChanged(_priorityAddress, valid);
                      }
                      /// @notice Assigns a new admin address for the protocol.
                      /// @param _newAdmin The address to be granted admin privileges.
                      /// @dev Only the current owner or existing admin can assign a new admin, ensuring secure management of protocol permissions.
                      /// Changing the admin address is a critical operation that should be performed with caution.
                      function setProtocolAdmin(address _newAdmin) external {
                          require(msg.sender == admin || msg.sender == owner(), "na");
                          admin = _newAdmin;
                          emit AdminChanged(_newAdmin);
                      }
                      //-------------------------------
                      //------- Users Functions -------
                      //-------------------------------
                      /// @notice Executes a smart swap operation through the XBridge, identified by a specific order ID.
                      /// @param orderId The unique identifier for the swap order, facilitating tracking and reference.
                      /// @param baseRequest Contains essential parameters for the swap, such as source and destination tokens, amount, minimum return, and deadline.
                      /// @param batchesAmount Array of amounts for each batch in the swap, allowing for split operations across different routes or pools.
                      /// @param batches Detailed paths for each swap batch, including adapters and target assets.
                      /// @param extraData Additional data required for executing the swap, which may include specific instructions or parameters for adapters.
                      /// @return returnAmount The total amount of the destination token received from the swap.
                      /// @dev This function allows for complex swap operations across different liquidity sources or protocols, initiated via the XBridge.
                      /// It's designed to be called by authorized addresses, ensuring that the swap meets predefined criteria and security measures.
                      function smartSwapByOrderIdByXBridge(
                          uint256 orderId,
                          BaseRequest calldata baseRequest,
                          uint256[] calldata batchesAmount,
                          RouterPath[][] calldata batches,
                          PMMLib.PMMSwapRequest[] calldata extraData
                      )
                          external
                          payable
                          isExpired(baseRequest.deadLine)
                          nonReentrant
                          onlyPriorityAddress
                          returns (uint256 returnAmount)
                      {
                          emit SwapOrderId(orderId);
                          (address payer, address receiver) = IXBridge(msg.sender)
                              .payerReceiver();
                          require(receiver != address(0), "not address(0)");
                          return
                              _smartSwapTo(payer, receiver, baseRequest, batchesAmount, batches);
                      }
                      /// @notice Executes a token swap using Unxswap protocol via XBridge for a specific order ID.
                      /// @param srcToken The source token's address to be swapped.
                      /// @param amount The amount of the source token to be swapped.
                      /// @param minReturn The minimum acceptable return amount of destination tokens to ensure the swap is executed within acceptable slippage.
                      /// @param pools Pool identifiers used for the swap, allowing for route optimization.
                      /// @return returnAmount The amount of destination tokens received from the swap.
                      /// @dev This function is designed to facilitate cross-protocol swaps through the XBridge,
                      /// enabling swaps that adhere to specific routing paths defined by the pools parameter.
                      /// It is accessible only to priority addresses, ensuring controlled access and execution.
                      function unxswapByOrderIdByXBridge(
                          uint256 srcToken,
                          uint256 amount,
                          uint256 minReturn,
                          // solhint-disable-next-line no-unused-vars
                          bytes32[] calldata pools
                      ) external payable onlyPriorityAddress returns (uint256 returnAmount) {
                          emit SwapOrderId((srcToken & _ORDER_ID_MASK) >> 160);
                          (address payer, address receiver) = IXBridge(msg.sender)
                              .payerReceiver();
                          require(receiver != address(0), "not address(0)");
                          return _unxswapTo(srcToken, amount, minReturn, payer, receiver, pools);
                      }
                      /// @notice Executes a token swap using the Uniswap V3 protocol through the XBridge, specifically catering to priority addresses.
                      /// @param receiver The address that will receive the swap funds.
                      /// @param amount The amount of the source token to be swapped.
                      /// @param minReturn The minimum acceptable amount of tokens to be received from the swap. This parameter ensures the swap does not proceed if the return is below the specified threshold, guarding against excessive slippage.
                      /// @param pools An array of pool identifiers used to define the swap route in the Uniswap V3 pools.
                      /// @return returnAmount The amount of tokens received from the swap.
                      /// @dev This function is exclusively accessible to priority addresses and is responsible for executing swaps on Uniswap V3 through the XBridge interface. It ensures that the swap meets the criteria set by the parameters and utilizes the _uniswapV3Swap internal function to perform the actual swap.
                      function uniswapV3SwapToByXBridge(
                          uint256 receiver,
                          uint256 amount,
                          uint256 minReturn,
                          uint256[] calldata pools
                      ) external payable onlyPriorityAddress returns (uint256 returnAmount) {
                          emit SwapOrderId((receiver & _ORDER_ID_MASK) >> 160);
                          (address payer, address receiver_) = IXBridge(msg.sender)
                              .payerReceiver();
                          require(receiver_ != address(0), "not address(0)");
                          return
                              _uniswapV3SwapTo(
                                  payer,
                                  uint160(receiver_),
                                  amount,
                                  minReturn,
                                  pools
                              );
                      }
                      /// @notice Executes a smart swap based on the given order ID, supporting complex multi-path swaps.
                      /// @param orderId The unique identifier for the swap order, facilitating tracking and reference.
                      /// @param baseRequest Struct containing the base parameters for the swap, including the source and destination tokens, amount, minimum return, and deadline.
                      /// @param batchesAmount An array specifying the amount to be swapped in each batch, allowing for split operations.
                      /// @param batches An array of RouterPath structs defining the routing paths for each batch, enabling swaps through multiple protocols or liquidity pools.
                      /// @param extraData Additional data required for some swaps, accommodating special instructions or parameters necessary for executing the swap.
                      /// @return returnAmount The total amount of destination tokens received from executing the swap.
                      /// @dev This function orchestrates a swap operation that may involve multiple steps, routes, or protocols based on the provided parameters.
                      /// It's designed to ensure flexibility and efficiency in finding the best swap paths.
                      function smartSwapByOrderId(
                          uint256 orderId,
                          BaseRequest calldata baseRequest,
                          uint256[] calldata batchesAmount,
                          RouterPath[][] calldata batches,
                          PMMLib.PMMSwapRequest[] calldata extraData
                      )
                          external
                          payable
                          isExpired(baseRequest.deadLine)
                          nonReentrant
                          returns (uint256 returnAmount)
                      {
                          emit SwapOrderId(orderId);
                          return
                              _smartSwapTo(
                                  msg.sender,
                                  msg.sender,
                                  baseRequest,
                                  batchesAmount,
                                  batches
                              );
                      }
                      /// @notice Executes a token swap using the Unxswap protocol based on a specified order ID.
                      /// @param srcToken The source token involved in the swap.
                      /// @param amount The amount of the source token to be swapped.
                      /// @param minReturn The minimum amount of tokens expected to be received to ensure the swap does not proceed under unfavorable conditions.
                      /// @param pools An array of pool identifiers specifying the pools to use for the swap, allowing for optimized routing.
                      /// @return returnAmount The amount of destination tokens received from the swap.
                      /// @dev This function allows users to perform token swaps based on predefined orders, leveraging the Unxswap protocol's liquidity pools. It ensures that the swap meets the user's specified minimum return criteria, enhancing trade efficiency and security.
                      function unxswapByOrderId(
                          uint256 srcToken,
                          uint256 amount,
                          uint256 minReturn,
                          // solhint-disable-next-line no-unused-vars
                          bytes32[] calldata pools
                      ) external payable returns (uint256 returnAmount) {
                          emit SwapOrderId((srcToken & _ORDER_ID_MASK) >> 160);
                          return
                              _unxswapTo(
                                  srcToken,
                                  amount,
                                  minReturn,
                                  msg.sender,
                                  msg.sender,
                                  pools
                              );
                      }
                      /// @notice Executes a swap tailored for investment purposes, adjusting swap amounts based on the contract's balance.
                      /// @param baseRequest Struct containing essential swap parameters like source and destination tokens, amounts, and deadline.
                      /// @param batchesAmount Array indicating how much of the source token to swap in each batch, facilitating diversified investments.
                      /// @param batches Detailed routing information for executing the swap across different paths or protocols.
                      /// @param extraData Additional data for swaps, supporting protocol-specific requirements.
                      /// @param to The address where the swapped tokens will be sent, typically an investment contract or pool.
                      /// @return returnAmount The total amount of destination tokens received, ready for investment.
                      /// @dev This function is designed for scenarios where investments are made in batches or through complex paths to optimize returns. Adjustments are made based on the contract's current token balance to ensure precise allocation.
                      function smartSwapByInvest(
                          BaseRequest calldata baseRequest,
                          uint256[] calldata batchesAmount,
                          RouterPath[][] calldata batches,
                          PMMLib.PMMSwapRequest[] calldata extraData,
                          address to
                      )
                          external
                          payable
                          isExpired(baseRequest.deadLine)
                          nonReentrant
                          returns (uint256 returnAmount)
                      {
                          address fromToken = _bytes32ToAddress(baseRequest.fromToken);
                          require(fromToken != _ETH, "Invalid source token");
                          uint256 amount = IERC20(fromToken).balanceOf(address(this));
                          BaseRequest memory newBaseRequest = BaseRequest({
                              fromToken: baseRequest.fromToken,
                              toToken: baseRequest.toToken,
                              fromTokenAmount: amount,
                              minReturnAmount: baseRequest.minReturnAmount,
                              deadLine: baseRequest.deadLine
                          });
                          uint256[] memory newBatchesAmount = new uint256[](batchesAmount.length);
                          for (uint256 i = 0; i < batchesAmount.length; ) {
                              newBatchesAmount[i] =
                                  (batchesAmount[i] * amount) /
                                  baseRequest.fromTokenAmount;
                              unchecked {
                                  ++i;
                              }
                          }
                          returnAmount = _smartSwapInternal(
                              newBaseRequest,
                              newBatchesAmount,
                              batches,
                              address(this),
                              to
                          );
                      }
                      /// @notice Executes a Uniswap V3 swap after obtaining a permit, allowing the approval of token spending and swap execution in a single transaction.
                      /// @param receiver The address that will receive the funds from the swap.
                      /// @param srcToken The token that will be swapped.
                      /// @param amount The amount of source tokens to be swapped.
                      /// @param minReturn The minimum acceptable amount of tokens to receive from the swap, guarding against slippage.
                      /// @param pools An array of Uniswap V3 pool identifiers, specifying the pools to be used for the swap.
                      /// @param permit A signed permit message that allows the router to spend the source tokens without requiring a separate `approve` transaction.
                      /// @return returnAmount The amount of tokens received from the swap.
                      /// @dev This function first utilizes the `_permit` function to approve token spending, then proceeds to execute the swap through `_uniswapV3Swap`. It's designed to streamline transactions by combining token approval and swap execution into a single operation.
                      function uniswapV3SwapToWithPermit(
                          uint256 receiver,
                          IERC20 srcToken,
                          uint256 amount,
                          uint256 minReturn,
                          uint256[] calldata pools,
                          bytes calldata permit
                      ) external returns (uint256 returnAmount) {
                          emit SwapOrderId((receiver & _ORDER_ID_MASK) >> 160);
                          _permit(address(srcToken), permit);
                          return _uniswapV3SwapTo(msg.sender, receiver, amount, minReturn, pools);
                      }
                      /// @notice Executes a swap using the Uniswap V3 protocol.
                      /// @param receiver The address that will receive the swap funds.
                      /// @param amount The amount of the source token to be swapped.
                      /// @param minReturn The minimum acceptable amount of tokens to receive from the swap, guarding against excessive slippage.
                      /// @param pools An array of pool identifiers used to define the swap route within Uniswap V3.
                      /// @return returnAmount The amount of tokens received after the completion of the swap.
                      /// @dev This function wraps and unwraps ETH as required, ensuring the transaction only accepts non-zero `msg.value` for ETH swaps. It invokes `_uniswapV3Swap` to execute the actual swap and handles commission post-swap.
                      function uniswapV3SwapTo(
                          uint256 receiver,
                          uint256 amount,
                          uint256 minReturn,
                          uint256[] calldata pools
                      ) external payable returns (uint256 returnAmount) {
                          emit SwapOrderId((receiver & _ORDER_ID_MASK) >> 160);
                          return _uniswapV3SwapTo(msg.sender, receiver, amount, minReturn, pools);
                      }
                      function _uniswapV3SwapTo(
                          address payer,
                          uint256 receiver,
                          uint256 amount,
                          uint256 minReturn,
                          uint256[] calldata pools
                      ) internal returns (uint256 returnAmount) {
                          CommissionInfo memory commissionInfo = _getCommissionInfo();
                          (
                              address middleReceiver,
                              uint256 balanceBefore
                          ) = _doCommissionFromToken(
                                  commissionInfo,
                                  address(uint160(receiver)),
                                  amount
                              );
                          (uint256 swappedAmount, ) = _uniswapV3Swap(
                              payer,
                              payable(middleReceiver),
                              amount,
                              minReturn,
                              pools
                          );
                          uint256 commissionAmount = _doCommissionToToken(
                              commissionInfo,
                              address(uint160(receiver)),
                              balanceBefore
                          );
                          return swappedAmount - commissionAmount;
                      }
                      /// @notice Executes a smart swap directly to a specified receiver address.
                      /// @param orderId Unique identifier for the swap order, facilitating tracking.
                      /// @param receiver Address to receive the output tokens from the swap.
                      /// @param baseRequest Contains essential parameters for the swap such as source and destination tokens, amounts, and deadline.
                      /// @param batchesAmount Array indicating amounts for each batch in the swap, allowing for split operations.
                      /// @param batches Detailed routing information for executing the swap across different paths or protocols.
                      /// @param extraData Additional data required for certain swaps, accommodating specific protocol needs.
                      /// @return returnAmount The total amount of destination tokens received from the swap.
                      /// @dev This function enables users to perform token swaps with complex routing directly to a specified address,
                      /// optimizing for best returns and accommodating specific trading strategies.
                      function smartSwapTo(
                          uint256 orderId,
                          address receiver,
                          BaseRequest calldata baseRequest,
                          uint256[] calldata batchesAmount,
                          RouterPath[][] calldata batches,
                          PMMLib.PMMSwapRequest[] calldata extraData
                      )
                          external
                          payable
                          isExpired(baseRequest.deadLine)
                          nonReentrant
                          returns (uint256 returnAmount)
                      {
                          emit SwapOrderId(orderId);
                          return
                              _smartSwapTo(
                                  msg.sender,
                                  receiver,
                                  baseRequest,
                                  batchesAmount,
                                  batches
                              );
                      }
                      function _smartSwapTo(
                          address payer,
                          address receiver,
                          BaseRequest calldata baseRequest,
                          uint256[] calldata batchesAmount,
                          RouterPath[][] calldata batches
                      ) internal returns (uint256) {
                          require(receiver != address(0), "not addr(0)");
                          CommissionInfo memory commissionInfo = _getCommissionInfo();
                          (
                              address middleReceiver,
                              uint256 balanceBefore
                          ) = _doCommissionFromToken(
                                  commissionInfo,
                                  receiver,
                                  baseRequest.fromTokenAmount
                              );
                          address _payer = payer; // avoid stack too deep
                          uint256 swappedAmount = _smartSwapInternal(
                              baseRequest,
                              batchesAmount,
                              batches,
                              _payer,
                              middleReceiver
                          );
                          uint256 commissionAmount = _doCommissionToToken(
                              commissionInfo,
                              receiver,
                              balanceBefore
                          );
                          return swappedAmount - commissionAmount;
                      }
                      /// @notice Executes a token swap using the Unxswap protocol, sending the output directly to a specified receiver.
                      /// @param srcToken The source token to be swapped.
                      /// @param amount The amount of the source token to be swapped.
                      /// @param minReturn The minimum amount of destination tokens expected from the swap, ensuring the trade does not proceed under unfavorable conditions.
                      /// @param receiver The address where the swapped tokens will be sent.
                      /// @param pools An array of pool identifiers to specify the swap route, optimizing for best rates.
                      /// @return returnAmount The total amount of destination tokens received from the swap.
                      /// @dev This function facilitates direct swaps using Unxswap, allowing users to specify custom swap routes and ensuring that the output is sent to a predetermined address. It is designed for scenarios where the user wants to directly receive the tokens in their wallet or another contract.
                      function unxswapTo(
                          uint256 srcToken,
                          uint256 amount,
                          uint256 minReturn,
                          address receiver,
                          // solhint-disable-next-line no-unused-vars
                          bytes32[] calldata pools
                      ) external payable returns (uint256 returnAmount) {
                          emit SwapOrderId((srcToken & _ORDER_ID_MASK) >> 160);
                          return
                              _unxswapTo(
                                  srcToken,
                                  amount,
                                  minReturn,
                                  msg.sender,
                                  receiver,
                                  pools
                              );
                      }
                      function _unxswapTo(
                          uint256 srcToken,
                          uint256 amount,
                          uint256 minReturn,
                          address payer,
                          address receiver,
                          // solhint-disable-next-line no-unused-vars
                          bytes32[] calldata pools
                      ) internal returns (uint256 returnAmount) {
                          require(receiver != address(0), "not addr(0)");
                          CommissionInfo memory commissionInfo = _getCommissionInfo();
                          (
                              address middleReceiver,
                              uint256 balanceBefore
                          ) = _doCommissionFromToken(commissionInfo, receiver, amount);
                          uint256 swappedAmount = _unxswapInternal(
                              IERC20(address(uint160(srcToken & _ADDRESS_MASK))),
                              amount,
                              minReturn,
                              pools,
                              payer,
                              middleReceiver
                          );
                          uint256 commissionAmount = _doCommissionToToken(
                              commissionInfo,
                              receiver,
                              balanceBefore
                          );
                          return swappedAmount - commissionAmount;
                      }
                      /// @notice Allows the contract owner to withdraw any tokens or native currency considered as "dust".
                      /// @param token The address of the token to withdraw, or the zero address for native currency.
                      /// @param to The address where the dust tokens or native currency should be sent.
                      /// @param amount The amount of the token or native currency to withdraw.
                      /// @dev This function is intended for recovering small amounts of tokens or native currency
                      /// left in the contract, which might not be recoverable through normal operations.
                      /// It can only be executed by the contract owner to ensure control over the contract's assets.
                      function withdrawDust(
                          address token,
                          address to,
                          uint256 amount
                      ) external onlyOwner {
                          if (token == _ETH) {
                              (bool success, bytes memory data) = payable(to).call{value: amount}(
                                  ""
                              );
                              require(success, string(data));
                          } else {
                              SafeERC20.safeTransfer(IERC20(token), to, amount);
                          }
                      }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  pragma abicoder v2;
                  interface IAdapter {
                      function sellBase(
                          address to,
                          address pool,
                          bytes memory data
                      ) external;
                      function sellQuote(
                          address to,
                          address pool,
                          bytes memory data
                      ) external;
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  interface IApproveProxy {
                      function isAllowedProxy(address _proxy) external view returns (bool);
                      function claimTokens(
                          address token,
                          address who,
                          address dest,
                          uint256 amount
                      ) external;
                      function tokenApprove() external view returns (address);
                      function addProxy(address) external;
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  /// @title Interface for DAI-style permits
                  interface IDaiLikePermit {
                      function permit(
                          address holder,
                          address spender,
                          uint256 nonce,
                          uint256 expiry,
                          bool allowed,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) external;
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  interface IERC20 {
                      event Approval(
                          address indexed owner,
                          address indexed spender,
                          uint256 value
                      );
                      event Transfer(address indexed from, address indexed to, uint256 value);
                      function name() external view returns (string memory);
                      function symbol() external view returns (string memory);
                      function decimals() external view returns (uint8);
                      function totalSupply() external view returns (uint256);
                      function balanceOf(address owner) external view returns (uint256);
                      function allowance(address owner, address spender)
                          external
                          view
                          returns (uint256);
                      function approve(address spender, uint256 value) external returns (bool);
                      function transfer(address to, uint256 value) external returns (bool);
                      function transferFrom(
                          address from,
                          address to,
                          uint256 value
                      ) external returns (bool);
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  /**
                   * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
                   * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
                   *
                   * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
                   * presenting a message signed by the account. By not relying on `{IERC20-approve}`, the token holder account doesn't
                   * need to send a transaction, and thus is not required to hold Ether at all.
                   */
                  interface IERC20Permit {
                      /**
                       * @dev Sets `value` as the allowance of `spender` over `owner`'s tokens,
                       * given `owner`'s signed approval.
                       *
                       * IMPORTANT: The same issues {IERC20-approve} has related to transaction
                       * ordering also apply here.
                       *
                       * Emits an {Approval} event.
                       *
                       * Requirements:
                       *
                       * - `spender` cannot be the zero address.
                       * - `deadline` must be a timestamp in the future.
                       * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
                       * over the EIP712-formatted function arguments.
                       * - the signature must use ``owner``'s current nonce (see {nonces}).
                       *
                       * For more information on the signature format, see the
                       * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
                       * section].
                       */
                      function permit(
                          address owner,
                          address spender,
                          uint256 value,
                          uint256 deadline,
                          uint8 v,
                          bytes32 r,
                          bytes32 s
                      ) external;
                      /**
                       * @dev Returns the current nonce for `owner`. This value must be
                       * included whenever a signature is generated for {permit}.
                       *
                       * Every successful call to {permit} increases ``owner``'s nonce by one. This
                       * prevents a signature from being used multiple times.
                       */
                      function nonces(address owner) external view returns (uint256);
                      /**
                       * @dev Returns the domain separator used in the encoding of the signature for `permit`, as defined by {EIP712}.
                       */
                      // solhint-disable-next-line func-name-mixedcase
                      function DOMAIN_SEPARATOR() external view returns (bytes32);
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  pragma abicoder v2;
                  interface IUni {
                      function swapExactTokensForTokens(
                          uint256 amountIn,
                          uint256 amountOutMin,
                          address[] calldata path,
                          address to,
                          uint256 deadline
                      ) external returns (uint256[] memory amounts);
                      function swap(
                          uint256 amount0Out,
                          uint256 amount1Out,
                          address to,
                          bytes calldata data
                      ) external;
                      function getReserves()
                          external
                          view
                          returns (
                              uint112 reserve0,
                              uint112 reserve1,
                              uint32 blockTimestampLast
                          );
                      function token0() external view returns (address);
                      function token1() external view returns (address);
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  /// @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: MIT
                  pragma solidity ^0.8.0;
                  pragma abicoder v2;
                  interface IUniV3 {
                      function swap(
                          address recipient,
                          bool zeroForOne,
                          int256 amountSpecified,
                          uint160 sqrtPriceLimitX96,
                          bytes calldata data
                      ) external returns (int256 amount0, int256 amount1);
                      function slot0()
                          external
                          view
                          returns (
                              uint160 sqrtPriceX96,
                              int24 tick,
                              uint16 observationIndex,
                              uint16 observationCardinality,
                              uint16 observationCardinalityNext,
                              uint8 feeProtocol,
                              bool unlocked
                          );
                      function token0() external view returns (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);
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  pragma abicoder v2;
                  interface IWETH {
                      function totalSupply() external view returns (uint256);
                      function balanceOf(address account) external view returns (uint256);
                      function transfer(address recipient, uint256 amount)
                          external
                          returns (bool);
                      function allowance(address owner, address spender)
                          external
                          view
                          returns (uint256);
                      function approve(address spender, uint256 amount) external returns (bool);
                      function transferFrom(
                          address src,
                          address dst,
                          uint256 wad
                      ) external returns (bool);
                      function deposit() external payable;
                      function withdraw(uint256 wad) external;
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  pragma abicoder v2;
                  interface IWNativeRelayer {
                      function withdraw(uint256 _amount) external;
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  pragma abicoder v2;
                  interface IXBridge {
                      function payerReceiver() external view returns(address, address);
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^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) {
                          // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
                          // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
                          // for accounts without code, i.e. `keccak256('')`
                          bytes32 codehash;
                          bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              codehash := extcodehash(account)
                          }
                          return (codehash != accountHash && codehash != 0x0);
                      }
                      /**
                       * @dev Converts an `address` into `address payable`. Note that this is
                       * simply a type cast: the actual underlying value is not changed.
                       *
                       * _Available since v2.4.0._
                       */
                      function toPayable(address account)
                          internal
                          pure
                          returns (address payable)
                      {
                          return payable(account);
                      }
                      /**
                       * @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].
                       *
                       * _Available since v2.4.0._
                       */
                      function sendValue(address recipient, uint256 amount) internal {
                          require(
                              address(this).balance >= amount,
                              "Address: insufficient balance"
                          );
                          // solhint-disable-next-line avoid-call-value
                          (bool success, ) = recipient.call{value: amount}("");
                          require(
                              success,
                              "Address: unable to send value, recipient may have reverted"
                          );
                      }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  import "./CommonUtils.sol";
                  /// @title Base contract with common permit handling logics
                  abstract contract CommissionLib is CommonUtils {
                      uint256 internal constant _COMMISSION_FEE_MASK =
                          0x000000000000ffffffffffff0000000000000000000000000000000000000000;
                      uint256 internal constant _COMMISSION_FLAG_MASK =
                          0xffffffffffff0000000000000000000000000000000000000000000000000000;
                      uint256 internal constant FROM_TOKEN_COMMISSION =
                          0x3ca20afc2aaa0000000000000000000000000000000000000000000000000000;
                      uint256 internal constant TO_TOKEN_COMMISSION =
                          0x3ca20afc2bbb0000000000000000000000000000000000000000000000000000;
                      event CommissionRecord(uint256 commissionAmount, address referrerAddress);
                      // set default vaule. can change when need.
                      uint256 public constant commissionRateLimit = 300;
                      struct CommissionInfo {
                          bool isFromTokenCommission;
                          bool isToTokenCommission;
                          uint256 commissionRate;
                          address refererAddress;
                          address token;
                      }
                      function _getCommissionInfo()
                          internal
                          pure
                          returns (CommissionInfo memory commissionInfo)
                      {
                          assembly ("memory-safe") {
                              let freePtr := mload(0x40)
                              mstore(0x40, add(freePtr, 0xa0))
                              let commissionData := calldataload(sub(calldatasize(), 0x20))
                              mstore(
                                  commissionInfo,
                                  eq(
                                      FROM_TOKEN_COMMISSION,
                                      and(commissionData, _COMMISSION_FLAG_MASK)
                                  )
                              ) // isFromTokenCommission
                              mstore(
                                  add(0x20, commissionInfo),
                                  eq(
                                      TO_TOKEN_COMMISSION,
                                      and(commissionData, _COMMISSION_FLAG_MASK)
                                  )
                              )
                              mstore(
                                  add(0x40, commissionInfo),
                                  shr(160, and(commissionData, _COMMISSION_FEE_MASK))
                              )
                              mstore(
                                  add(0x60, commissionInfo),
                                  and(commissionData, _ADDRESS_MASK)
                              )
                              mstore(
                                  add(0x80, commissionInfo),
                                  and(calldataload(sub(calldatasize(), 0x40)), _ADDRESS_MASK)
                              )
                          }
                      }
                      function _getBalanceOf(
                          address token,
                          address user
                      ) internal returns (uint256 amount) {
                          assembly {
                              function _revertWithReason(m, len) {
                                  mstore(
                                      0,
                                      0x08c379a000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(
                                      0x20,
                                      0x0000002000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(0x40, m)
                                  revert(0, len)
                              }
                              switch eq(token, _ETH)
                              case 1 {
                                  amount := selfbalance()
                              }
                              default {
                                  let freePtr := mload(0x40)
                                  mstore(0x40, add(freePtr, 0x24))
                                  mstore(
                                      freePtr,
                                      0x70a0823100000000000000000000000000000000000000000000000000000000
                                  ) //balanceOf
                                  mstore(add(freePtr, 0x04), user)
                                  let success := staticcall(gas(), token, freePtr, 0x24, 0, 0x20)
                                  if eq(success, 0) {
                                      _revertWithReason(
                                          0x000000146765742062616c616e63654f66206661696c65640000000000000000,
                                          0x58
                                      )
                                  }
                                  amount := mload(0x00)
                              }
                          }
                      }
                      function _doCommissionFromToken(
                          CommissionInfo memory commissionInfo,
                          address receiver,
                          uint256 inputAmount
                      ) internal returns (address, uint256) {
                          if (commissionInfo.isToTokenCommission) {
                              return (
                                  address(this),
                                  _getBalanceOf(commissionInfo.token, address(this))
                              );
                          }
                          if (!commissionInfo.isFromTokenCommission) {
                              return (receiver, 0);
                          }
                          assembly ("memory-safe") {
                              function _revertWithReason(m, len) {
                                  mstore(
                                      0,
                                      0x08c379a000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(
                                      0x20,
                                      0x0000002000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(0x40, m)
                                  revert(0, len)
                              }
                              let rate := mload(add(commissionInfo, 0x40))
                              if gt(rate, commissionRateLimit) {
                                  _revertWithReason(
                                      0x0000001b6572726f7220636f6d6d697373696f6e2072617465206c696d697400,
                                      0x5f
                                  ) //"error commission rate limit"
                              }
                              let token := mload(add(commissionInfo, 0x80))
                              let referer := mload(add(commissionInfo, 0x60))
                              let amount := div(mul(inputAmount, rate), sub(10000, rate))
                              switch eq(token, _ETH)
                              case 1 {
                                  let success := call(gas(), referer, amount, 0, 0, 0, 0)
                                  if eq(success, 0) {
                                      _revertWithReason(
                                          0x0000001b636f6d6d697373696f6e2077697468206574686572206572726f7200,
                                          0x5f
                                      )
                                  }
                              }
                              default {
                                  let freePtr := mload(0x40)
                                  mstore(0x40, add(freePtr, 0x84))
                                  mstore(
                                      freePtr,
                                      0x0a5ea46600000000000000000000000000000000000000000000000000000000
                                  ) // claimTokens
                                  mstore(add(freePtr, 0x04), token)
                                  mstore(add(freePtr, 0x24), caller())
                                  mstore(add(freePtr, 0x44), referer)
                                  mstore(add(freePtr, 0x64), amount)
                                  let success := call(
                                      gas(),
                                      _APPROVE_PROXY,
                                      0,
                                      freePtr,
                                      0x84,
                                      0,
                                      0
                                  )
                                  if eq(success, 0) {
                                      _revertWithReason(
                                          0x00000013636c61696d20746f6b656e73206661696c6564000000000000000000,
                                          0x57
                                      )
                                  }
                              }
                              let freePtr := mload(0x40)
                              mstore(0x40, add(freePtr, 0x40))
                              mstore(freePtr, amount)
                              mstore(add(freePtr, 0x20), referer)
                              log1(
                                  freePtr,
                                  0x40,
                                  0xffc60ee157a42f4d8edbd1897e6581a96d9ed04e44fb2ab53a47ce1eb8f2775b
                              ) //emit CommissionRecord(commissionAmount, refererAddress);
                          }
                          return (receiver, 0);
                      }
                      function _doCommissionToToken(
                          CommissionInfo memory commissionInfo,
                          address receiver,
                          uint256 balanceBefore
                      ) internal returns (uint256 amount) {
                          if (!commissionInfo.isToTokenCommission) {
                              return 0;
                          }
                          assembly ("memory-safe") {
                              function _revertWithReason(m, len) {
                                  mstore(
                                      0,
                                      0x08c379a000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(
                                      0x20,
                                      0x0000002000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(0x40, m)
                                  revert(0, len)
                              }
                              let rate := mload(add(commissionInfo, 0x40))
                              if gt(rate, commissionRateLimit) {
                                  _revertWithReason(
                                      0x0000001b6572726f7220636f6d6d697373696f6e2072617465206c696d697400,
                                      0x5f
                                  ) //"error commission rate limit"
                              }
                              let token := mload(add(commissionInfo, 0x80))
                              let referer := mload(add(commissionInfo, 0x60))
                              switch eq(token, _ETH)
                              case 1 {
                                  if lt(selfbalance(), balanceBefore) {
                                      _revertWithReason(
                                          0x0000000a737562206661696c65640000000000000000000000000000000000000,
                                          0x4d
                                      ) // sub failed
                                  }
                                  let inputAmount := sub(selfbalance(), balanceBefore)
                                  amount := div(mul(inputAmount, rate), 10000)
                                  let success := call(gas(), referer, amount, 0, 0, 0, 0)
                                  if eq(success, 0) {
                                      _revertWithReason(
                                          0x000000197472616e73666572206574682072656665726572206661696c000000,
                                          0x5d
                                      ) // transfer eth referer fail
                                  }
                                  success := call(
                                      gas(),
                                      receiver,
                                      sub(inputAmount, amount),
                                      0,
                                      0,
                                      0,
                                      0
                                  )
                                  if eq(success, 0) {
                                      _revertWithReason(
                                          0x0000001a7472616e7366657220657468207265636569766572206661696c0000,
                                          0x5e
                                      ) // transfer eth receiver fail
                                  }
                              }
                              default {
                                  let freePtr := mload(0x40)
                                  mstore(0x40, add(freePtr, 0x48))
                                  mstore(
                                      freePtr,
                                      0xa9059cbba9059cbb70a082310000000000000000000000000000000000000000
                                  ) // transfer transfer balanceOf
                                  mstore(add(freePtr, 0x0c), address())
                                  let success := staticcall(
                                      gas(),
                                      token,
                                      add(freePtr, 8),
                                      36,
                                      0,
                                      0x20
                                  )
                                  if eq(success, 0) {
                                      _revertWithReason(
                                          0x000000146765742062616c616e63654f66206661696c65640000000000000000,
                                          0x58
                                      )
                                  }
                                  let balanceAfter := mload(0x00)
                                  if lt(balanceAfter, balanceBefore) {
                                      _revertWithReason(
                                          0x0000000a737562206661696c65640000000000000000000000000000000000000,
                                          0x4d
                                      ) // sub failed
                                  }
                                  let inputAmount := sub(balanceAfter, balanceBefore)
                                  amount := div(mul(inputAmount, rate), 10000)
                                  mstore(add(freePtr, 0x08), referer)
                                  mstore(add(freePtr, 0x28), amount)
                                  success := call(gas(), token, 0, add(freePtr, 4), 0x44, 0, 0)
                                  if eq(success, 0) {
                                      _revertWithReason(
                                          0x0000001b7472616e7366657220746f6b656e2072656665726572206661696c00,
                                          0x5f
                                      ) //transfer token referer fail
                                  }
                                  mstore(add(freePtr, 0x04), receiver)
                                  mstore(add(freePtr, 0x24), sub(inputAmount, amount))
                                  success := call(gas(), token, 0, freePtr, 0x44, 0, 0)
                                  if eq(success, 0) {
                                      _revertWithReason(
                                          0x0000001c7472616e7366657220746f6b656e207265636569766572206661696c,
                                          0x60
                                      ) //transfer token receiver fail
                                  }
                              }
                              let freePtr := mload(0x40)
                              mstore(0x40, add(freePtr, 0x40))
                              mstore(freePtr, amount)
                              mstore(add(freePtr, 0x20), referer)
                              log1(
                                  freePtr,
                                  0x40,
                                  0xffc60ee157a42f4d8edbd1897e6581a96d9ed04e44fb2ab53a47ce1eb8f2775b
                              ) //emit CommissionRecord(commissionAmount, refererAddress);
                          }
                      }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  /// @title Base contract with common permit handling logics
                  abstract contract CommonUtils {
                    address internal constant _ETH = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
                    uint256 internal constant _ADDRESS_MASK = 0x000000000000000000000000ffffffffffffffffffffffffffffffffffffffff;
                    uint256 internal constant _REVERSE_MASK = 0x8000000000000000000000000000000000000000000000000000000000000000;
                    uint256 internal constant _ORDER_ID_MASK = 0xffffffffffffffffffffffff0000000000000000000000000000000000000000;
                    uint256 internal constant _WEIGHT_MASK = 0x00000000000000000000ffff0000000000000000000000000000000000000000;
                    uint256 internal constant _CALL_GAS_LIMIT = 5000;
                    /// @dev WETH address is network-specific and needs to be changed before deployment.
                    /// It can not be moved to immutable as immutables are not supported in assembly
                    // ETH:     C02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2
                    // BSC:     bb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c
                    // OEC:     8f8526dbfd6e38e3d8307702ca8469bae6c56c15
                    // LOCAL:   5FbDB2315678afecb367f032d93F642f64180aa3
                    // LOCAL2:  02121128f1Ed0AdA5Df3a87f42752fcE4Ad63e59
                    // POLYGON: 0d500B1d8E8eF31E21C99d1Db9A6444d3ADf1270
                    // AVAX:    B31f66AA3C1e785363F0875A1B74E27b85FD66c7
                    // FTM:     21be370D5312f44cB42ce377BC9b8a0cEF1A4C83
                    // ARB:     82aF49447D8a07e3bd95BD0d56f35241523fBab1
                    // OP:      4200000000000000000000000000000000000006
                    // CRO:     5C7F8A570d578ED84E63fdFA7b1eE72dEae1AE23
                    // CFX:     14b2D3bC65e74DAE1030EAFd8ac30c533c976A9b
                    // POLYZK   4F9A0e7FD2Bf6067db6994CF12E4495Df938E6e9
                    address public constant _WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
                    // address public constant _WETH = 0x5FbDB2315678afecb367f032d93F642f64180aa3;    // hardhat1
                    // address public constant _WETH = 0x707531c9999AaeF9232C8FEfBA31FBa4cB78d84a;    // hardhat2
                    // ETH:     70cBb871E8f30Fc8Ce23609E9E0Ea87B6b222F58
                    // ETH-DEV:02D0131E5Cc86766e234EbF1eBe33444443b98a3
                    // BSC:     d99cAE3FAC551f6b6Ba7B9f19bDD316951eeEE98
                    // OEC:     E9BBD6eC0c9Ca71d3DcCD1282EE9de4F811E50aF
                    // LOCAL:   e7f1725E7734CE288F8367e1Bb143E90bb3F0512
                    // LOCAL2:  95D7fF1684a8F2e202097F28Dc2e56F773A55D02
                    // POLYGON: 40aA958dd87FC8305b97f2BA922CDdCa374bcD7f
                    // AVAX:    70cBb871E8f30Fc8Ce23609E9E0Ea87B6b222F58
                    // FTM:     E9BBD6eC0c9Ca71d3DcCD1282EE9de4F811E50aF
                    // ARB:     E9BBD6eC0c9Ca71d3DcCD1282EE9de4F811E50aF
                    // OP:      100F3f74125C8c724C7C0eE81E4dd5626830dD9a
                    // CRO:     E9BBD6eC0c9Ca71d3DcCD1282EE9de4F811E50aF
                    // CFX:     100F3f74125C8c724C7C0eE81E4dd5626830dD9a
                    // POLYZK   1b5d39419C268b76Db06DE49e38B010fbFB5e226
                    address public constant _APPROVE_PROXY = 0x70cBb871E8f30Fc8Ce23609E9E0Ea87B6b222F58;
                    // address public constant _APPROVE_PROXY = 0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512;    // hardhat1
                    // address public constant _APPROVE_PROXY = 0x2538a10b7fFb1B78c890c870FC152b10be121f04;    // hardhat2
                    // ETH:     5703B683c7F928b721CA95Da988d73a3299d4757
                    // BSC:     0B5f474ad0e3f7ef629BD10dbf9e4a8Fd60d9A48
                    // OEC:     d99cAE3FAC551f6b6Ba7B9f19bDD316951eeEE98
                    // LOCAL:   D49a0e9A4CD5979aE36840f542D2d7f02C4817Be
                    // LOCAL2:  11457D5b1025D162F3d9B7dBeab6E1fBca20e043
                    // POLYGON: f332761c673b59B21fF6dfa8adA44d78c12dEF09
                    // AVAX:    3B86917369B83a6892f553609F3c2F439C184e31
                    // FTM:     40aA958dd87FC8305b97f2BA922CDdCa374bcD7f
                    // ARB:     d99cAE3FAC551f6b6Ba7B9f19bDD316951eeEE98
                    // OP:      40aA958dd87FC8305b97f2BA922CDdCa374bcD7f
                    // CRO:     40aA958dd87FC8305b97f2BA922CDdCa374bcD7f
                    // CFX:     40aA958dd87FC8305b97f2BA922CDdCa374bcD7f
                    // POLYZK   d2F0aC2012C8433F235c8e5e97F2368197DD06C7
                    address public constant _WNATIVE_RELAY = 0x5703B683c7F928b721CA95Da988d73a3299d4757;
                    // address public constant _WNATIVE_RELAY = 0x0B306BF915C4d645ff596e518fAf3F9669b97016;   // hardhat1
                    // address public constant _WNATIVE_RELAY = 0x6A47346e722937B60Df7a1149168c0E76DD6520f;   // hardhat2
                    event OrderRecord(address fromToken, address toToken, address sender, uint256 fromAmount, uint256 returnAmount);
                    event SwapOrderId(uint256 id);
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  /// @title Base contract with common payable logics
                  abstract contract EthReceiver {
                    receive() external payable {
                      // solhint-disable-next-line avoid-tx-origin
                      require(msg.sender != tx.origin, "ETH deposit rejected");
                    }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  import "../interfaces/IERC20Permit.sol";
                  import "../interfaces/IDaiLikePermit.sol";
                  import "./RevertReasonParser.sol";
                  /// @title Base contract with common permit handling logics
                  abstract contract Permitable {
                    function _permit(address token, bytes calldata permit) internal {
                      if (permit.length > 0) {
                        bool success;
                        bytes memory result;
                        if (permit.length == 32 * 7) {
                          // solhint-disable-next-line avoid-low-level-calls
                          (success, result) = token.call(abi.encodePacked(IERC20Permit.permit.selector, permit));
                        } else if (permit.length == 32 * 8) {
                          // solhint-disable-next-line avoid-low-level-calls
                          (success, result) = token.call(abi.encodePacked(IDaiLikePermit.permit.selector, permit));
                        } else {
                          revert("Wrong permit length");
                        }
                        if (!success) {
                          revert(RevertReasonParser.parse(result, "Permit failed: "));
                        }
                      }
                    }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  library PMMLib {
                    // ============ Struct ============
                    struct PMMSwapRequest {
                        uint256 pathIndex;
                        address payer;
                        address fromToken;
                        address toToken;
                        uint256 fromTokenAmountMax;
                        uint256 toTokenAmountMax;
                        uint256 salt;
                        uint256 deadLine;
                        bool isPushOrder;
                        bytes extension;
                        // address marketMaker;
                        // uint256 subIndex;
                        // bytes signature;
                        // uint256 source;  1byte type + 1byte bool(reverse) + 0...0 + 20 bytes address
                    }
                    struct PMMBaseRequest {
                      uint256 fromTokenAmount;
                      uint256 minReturnAmount;
                      uint256 deadLine;
                      bool fromNative;
                      bool toNative;
                    }
                    enum PMM_ERROR {
                        NO_ERROR,
                        INVALID_OPERATOR,
                        QUOTE_EXPIRED,
                        ORDER_CANCELLED_OR_FINALIZED,
                        REMAINING_AMOUNT_NOT_ENOUGH,
                        INVALID_AMOUNT_REQUEST,
                        FROM_TOKEN_PAYER_ERROR,
                        TO_TOKEN_PAYER_ERROR,
                        WRONG_FROM_TOKEN
                    }
                    event PMMSwap(
                      uint256 pathIndex,
                      uint256 subIndex,
                      uint256 errorCode
                    );
                    error PMMErrorCode(uint256 errorCode);
                  }/// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  library RevertReasonForwarder {
                      function reRevert() internal pure {
                          // bubble up revert reason from latest external call
                          /// @solidity memory-safe-assembly
                          assembly { // solhint-disable-line no-inline-assembly
                              let ptr := mload(0x40)
                              returndatacopy(ptr, 0, returndatasize())
                              revert(ptr, returndatasize())
                          }
                      }
                  }// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  /// @title Library that allows to parse unsuccessful arbitrary calls revert reasons.
                  /// See https://solidity.readthedocs.io/en/latest/control-structures.html#revert for details.
                  /// Note that we assume revert reason being abi-encoded as Error(string) so it may fail to parse reason
                  /// if structured reverts appear in the future.
                  ///
                  /// All unsuccessful parsings get encoded as Unknown(data) string
                  library RevertReasonParser {
                      bytes4 private constant _PANIC_SELECTOR =
                          bytes4(keccak256("Panic(uint256)"));
                      bytes4 private constant _ERROR_SELECTOR =
                          bytes4(keccak256("Error(string)"));
                      function parse(bytes memory data, string memory prefix)
                          internal
                          pure
                          returns (string memory)
                      {
                          if (data.length >= 4) {
                              bytes4 selector;
                              assembly {
                                  // solhint-disable-line no-inline-assembly
                                  selector := mload(add(data, 0x20))
                              }
                              // 68 = 4-byte selector + 32 bytes offset + 32 bytes length
                              if (selector == _ERROR_SELECTOR && data.length >= 68) {
                                  uint256 offset;
                                  bytes memory reason;
                                  // solhint-disable no-inline-assembly
                                  assembly {
                                      // 36 = 32 bytes data length + 4-byte selector
                                      offset := mload(add(data, 36))
                                      reason := add(data, add(36, offset))
                                  }
                                  /*
                                      revert reason is padded up to 32 bytes with ABI encoder: Error(string)
                                      also sometimes there is extra 32 bytes of zeros padded in the end:
                                      https://github.com/ethereum/solidity/issues/10170
                                      because of that we can't check for equality and instead check
                                      that offset + string length + extra 36 bytes is less than overall data length
                                  */
                                  require(
                                      data.length >= 36 + offset + reason.length,
                                      "Invalid revert reason"
                                  );
                                  return string(abi.encodePacked(prefix, "Error(", reason, ")"));
                              }
                              // 36 = 4-byte selector + 32 bytes integer
                              else if (selector == _PANIC_SELECTOR && data.length == 36) {
                                  uint256 code;
                                  // solhint-disable no-inline-assembly
                                  assembly {
                                      // 36 = 32 bytes data length + 4-byte selector
                                      code := mload(add(data, 36))
                                  }
                                  return
                                      string(
                                          abi.encodePacked(prefix, "Panic(", _toHex(code), ")")
                                      );
                              }
                          }
                          return string(abi.encodePacked(prefix, "Unknown(", _toHex(data), ")"));
                      }
                      function _toHex(uint256 value) private pure returns (string memory) {
                          return _toHex(abi.encodePacked(value));
                      }
                      function _toHex(bytes memory data) private pure returns (string memory) {
                          bytes16 alphabet = 0x30313233343536373839616263646566;
                          bytes memory str = new bytes(2 + data.length * 2);
                          str[0] = "0";
                          str[1] = "x";
                          for (uint256 i = 0; i < data.length; i++) {
                              str[2 * i + 2] = alphabet[uint8(data[i] >> 4)];
                              str[2 * i + 3] = alphabet[uint8(data[i] & 0x0f)];
                          }
                          return string(str);
                      }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity 0.8.17;
                  library RouterErrors {
                      error ReturnAmountIsNotEnough();
                      error InvalidMsgValue();
                      error ERC20TransferFailed();
                      error EmptyPools();
                      error InvalidFromToken();
                      error MsgValuedNotRequired();
                  }/// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  /**
                   * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
                   * checks.
                   *
                   * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
                   * easily result in undesired exploitation or bugs, since developers usually
                   * assume that overflows raise errors. `SafeCast` restores this intuition by
                   * reverting the transaction when such 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.
                   *
                   * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
                   * all math on `uint256` and `int256` and then downcasting.
                   */
                  library SafeCast {
                      /**
                       * @dev Returns the downcasted uint248 from uint256, reverting on
                       * overflow (when the input is greater than largest uint248).
                       *
                       * Counterpart to Solidity's `uint248` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 248 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint248(uint256 value) internal pure returns (uint248) {
                          require(value <= type(uint248).max, "SafeCast: value doesn't fit in 248 bits");
                          return uint248(value);
                      }
                      /**
                       * @dev Returns the downcasted uint240 from uint256, reverting on
                       * overflow (when the input is greater than largest uint240).
                       *
                       * Counterpart to Solidity's `uint240` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 240 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint240(uint256 value) internal pure returns (uint240) {
                          require(value <= type(uint240).max, "SafeCast: value doesn't fit in 240 bits");
                          return uint240(value);
                      }
                      /**
                       * @dev Returns the downcasted uint232 from uint256, reverting on
                       * overflow (when the input is greater than largest uint232).
                       *
                       * Counterpart to Solidity's `uint232` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 232 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint232(uint256 value) internal pure returns (uint232) {
                          require(value <= type(uint232).max, "SafeCast: value doesn't fit in 232 bits");
                          return uint232(value);
                      }
                      /**
                       * @dev Returns the downcasted uint224 from uint256, reverting on
                       * overflow (when the input is greater than largest uint224).
                       *
                       * Counterpart to Solidity's `uint224` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 224 bits
                       *
                       * _Available since v4.2._
                       */
                      function toUint224(uint256 value) internal pure returns (uint224) {
                          require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
                          return uint224(value);
                      }
                      /**
                       * @dev Returns the downcasted uint216 from uint256, reverting on
                       * overflow (when the input is greater than largest uint216).
                       *
                       * Counterpart to Solidity's `uint216` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 216 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint216(uint256 value) internal pure returns (uint216) {
                          require(value <= type(uint216).max, "SafeCast: value doesn't fit in 216 bits");
                          return uint216(value);
                      }
                      /**
                       * @dev Returns the downcasted uint208 from uint256, reverting on
                       * overflow (when the input is greater than largest uint208).
                       *
                       * Counterpart to Solidity's `uint208` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 208 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint208(uint256 value) internal pure returns (uint208) {
                          require(value <= type(uint208).max, "SafeCast: value doesn't fit in 208 bits");
                          return uint208(value);
                      }
                      /**
                       * @dev Returns the downcasted uint200 from uint256, reverting on
                       * overflow (when the input is greater than largest uint200).
                       *
                       * Counterpart to Solidity's `uint200` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 200 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint200(uint256 value) internal pure returns (uint200) {
                          require(value <= type(uint200).max, "SafeCast: value doesn't fit in 200 bits");
                          return uint200(value);
                      }
                      /**
                       * @dev Returns the downcasted uint192 from uint256, reverting on
                       * overflow (when the input is greater than largest uint192).
                       *
                       * Counterpart to Solidity's `uint192` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 192 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint192(uint256 value) internal pure returns (uint192) {
                          require(value <= type(uint192).max, "SafeCast: value doesn't fit in 192 bits");
                          return uint192(value);
                      }
                      /**
                       * @dev Returns the downcasted uint184 from uint256, reverting on
                       * overflow (when the input is greater than largest uint184).
                       *
                       * Counterpart to Solidity's `uint184` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 184 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint184(uint256 value) internal pure returns (uint184) {
                          require(value <= type(uint184).max, "SafeCast: value doesn't fit in 184 bits");
                          return uint184(value);
                      }
                      /**
                       * @dev Returns the downcasted uint176 from uint256, reverting on
                       * overflow (when the input is greater than largest uint176).
                       *
                       * Counterpart to Solidity's `uint176` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 176 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint176(uint256 value) internal pure returns (uint176) {
                          require(value <= type(uint176).max, "SafeCast: value doesn't fit in 176 bits");
                          return uint176(value);
                      }
                      /**
                       * @dev Returns the downcasted uint168 from uint256, reverting on
                       * overflow (when the input is greater than largest uint168).
                       *
                       * Counterpart to Solidity's `uint168` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 168 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint168(uint256 value) internal pure returns (uint168) {
                          require(value <= type(uint168).max, "SafeCast: value doesn't fit in 168 bits");
                          return uint168(value);
                      }
                      /**
                       * @dev Returns the downcasted uint160 from uint256, reverting on
                       * overflow (when the input is greater than largest uint160).
                       *
                       * Counterpart to Solidity's `uint160` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 160 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint160(uint256 value) internal pure returns (uint160) {
                          require(value <= type(uint160).max, "SafeCast: value doesn't fit in 160 bits");
                          return uint160(value);
                      }
                      /**
                       * @dev Returns the downcasted uint152 from uint256, reverting on
                       * overflow (when the input is greater than largest uint152).
                       *
                       * Counterpart to Solidity's `uint152` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 152 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint152(uint256 value) internal pure returns (uint152) {
                          require(value <= type(uint152).max, "SafeCast: value doesn't fit in 152 bits");
                          return uint152(value);
                      }
                      /**
                       * @dev Returns the downcasted uint144 from uint256, reverting on
                       * overflow (when the input is greater than largest uint144).
                       *
                       * Counterpart to Solidity's `uint144` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 144 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint144(uint256 value) internal pure returns (uint144) {
                          require(value <= type(uint144).max, "SafeCast: value doesn't fit in 144 bits");
                          return uint144(value);
                      }
                      /**
                       * @dev Returns the downcasted uint136 from uint256, reverting on
                       * overflow (when the input is greater than largest uint136).
                       *
                       * Counterpart to Solidity's `uint136` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 136 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint136(uint256 value) internal pure returns (uint136) {
                          require(value <= type(uint136).max, "SafeCast: value doesn't fit in 136 bits");
                          return uint136(value);
                      }
                      /**
                       * @dev Returns the downcasted uint128 from uint256, reverting on
                       * overflow (when the input is greater than largest uint128).
                       *
                       * Counterpart to Solidity's `uint128` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 128 bits
                       *
                       * _Available since v2.5._
                       */
                      function toUint128(uint256 value) internal pure returns (uint128) {
                          require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
                          return uint128(value);
                      }
                      /**
                       * @dev Returns the downcasted uint120 from uint256, reverting on
                       * overflow (when the input is greater than largest uint120).
                       *
                       * Counterpart to Solidity's `uint120` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 120 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint120(uint256 value) internal pure returns (uint120) {
                          require(value <= type(uint120).max, "SafeCast: value doesn't fit in 120 bits");
                          return uint120(value);
                      }
                      /**
                       * @dev Returns the downcasted uint112 from uint256, reverting on
                       * overflow (when the input is greater than largest uint112).
                       *
                       * Counterpart to Solidity's `uint112` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 112 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint112(uint256 value) internal pure returns (uint112) {
                          require(value <= type(uint112).max, "SafeCast: value doesn't fit in 112 bits");
                          return uint112(value);
                      }
                      /**
                       * @dev Returns the downcasted uint104 from uint256, reverting on
                       * overflow (when the input is greater than largest uint104).
                       *
                       * Counterpart to Solidity's `uint104` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 104 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint104(uint256 value) internal pure returns (uint104) {
                          require(value <= type(uint104).max, "SafeCast: value doesn't fit in 104 bits");
                          return uint104(value);
                      }
                      /**
                       * @dev Returns the downcasted uint96 from uint256, reverting on
                       * overflow (when the input is greater than largest uint96).
                       *
                       * Counterpart to Solidity's `uint96` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 96 bits
                       *
                       * _Available since v4.2._
                       */
                      function toUint96(uint256 value) internal pure returns (uint96) {
                          require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
                          return uint96(value);
                      }
                      /**
                       * @dev Returns the downcasted uint88 from uint256, reverting on
                       * overflow (when the input is greater than largest uint88).
                       *
                       * Counterpart to Solidity's `uint88` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 88 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint88(uint256 value) internal pure returns (uint88) {
                          require(value <= type(uint88).max, "SafeCast: value doesn't fit in 88 bits");
                          return uint88(value);
                      }
                      /**
                       * @dev Returns the downcasted uint80 from uint256, reverting on
                       * overflow (when the input is greater than largest uint80).
                       *
                       * Counterpart to Solidity's `uint80` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 80 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint80(uint256 value) internal pure returns (uint80) {
                          require(value <= type(uint80).max, "SafeCast: value doesn't fit in 80 bits");
                          return uint80(value);
                      }
                      /**
                       * @dev Returns the downcasted uint72 from uint256, reverting on
                       * overflow (when the input is greater than largest uint72).
                       *
                       * Counterpart to Solidity's `uint72` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 72 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint72(uint256 value) internal pure returns (uint72) {
                          require(value <= type(uint72).max, "SafeCast: value doesn't fit in 72 bits");
                          return uint72(value);
                      }
                      /**
                       * @dev Returns the downcasted uint64 from uint256, reverting on
                       * overflow (when the input is greater than largest uint64).
                       *
                       * Counterpart to Solidity's `uint64` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 64 bits
                       *
                       * _Available since v2.5._
                       */
                      function toUint64(uint256 value) internal pure returns (uint64) {
                          require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
                          return uint64(value);
                      }
                      /**
                       * @dev Returns the downcasted uint56 from uint256, reverting on
                       * overflow (when the input is greater than largest uint56).
                       *
                       * Counterpart to Solidity's `uint56` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 56 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint56(uint256 value) internal pure returns (uint56) {
                          require(value <= type(uint56).max, "SafeCast: value doesn't fit in 56 bits");
                          return uint56(value);
                      }
                      /**
                       * @dev Returns the downcasted uint48 from uint256, reverting on
                       * overflow (when the input is greater than largest uint48).
                       *
                       * Counterpart to Solidity's `uint48` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 48 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint48(uint256 value) internal pure returns (uint48) {
                          require(value <= type(uint48).max, "SafeCast: value doesn't fit in 48 bits");
                          return uint48(value);
                      }
                      /**
                       * @dev Returns the downcasted uint40 from uint256, reverting on
                       * overflow (when the input is greater than largest uint40).
                       *
                       * Counterpart to Solidity's `uint40` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 40 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint40(uint256 value) internal pure returns (uint40) {
                          require(value <= type(uint40).max, "SafeCast: value doesn't fit in 40 bits");
                          return uint40(value);
                      }
                      /**
                       * @dev Returns the downcasted uint32 from uint256, reverting on
                       * overflow (when the input is greater than largest uint32).
                       *
                       * Counterpart to Solidity's `uint32` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 32 bits
                       *
                       * _Available since v2.5._
                       */
                      function toUint32(uint256 value) internal pure returns (uint32) {
                          require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
                          return uint32(value);
                      }
                      /**
                       * @dev Returns the downcasted uint24 from uint256, reverting on
                       * overflow (when the input is greater than largest uint24).
                       *
                       * Counterpart to Solidity's `uint24` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 24 bits
                       *
                       * _Available since v4.7._
                       */
                      function toUint24(uint256 value) internal pure returns (uint24) {
                          require(value <= type(uint24).max, "SafeCast: value doesn't fit in 24 bits");
                          return uint24(value);
                      }
                      /**
                       * @dev Returns the downcasted uint16 from uint256, reverting on
                       * overflow (when the input is greater than largest uint16).
                       *
                       * Counterpart to Solidity's `uint16` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 16 bits
                       *
                       * _Available since v2.5._
                       */
                      function toUint16(uint256 value) internal pure returns (uint16) {
                          require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
                          return uint16(value);
                      }
                      /**
                       * @dev Returns the downcasted uint8 from uint256, reverting on
                       * overflow (when the input is greater than largest uint8).
                       *
                       * Counterpart to Solidity's `uint8` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 8 bits
                       *
                       * _Available since v2.5._
                       */
                      function toUint8(uint256 value) internal pure returns (uint8) {
                          require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
                          return uint8(value);
                      }
                      /**
                       * @dev Converts a signed int256 into an unsigned uint256.
                       *
                       * Requirements:
                       *
                       * - input must be greater than or equal to 0.
                       *
                       * _Available since v3.0._
                       */
                      function toUint256(int256 value) internal pure returns (uint256) {
                          require(value >= 0, "SafeCast: value must be positive");
                          return uint256(value);
                      }
                      /**
                       * @dev Returns the downcasted int248 from int256, reverting on
                       * overflow (when the input is less than smallest int248 or
                       * greater than largest int248).
                       *
                       * Counterpart to Solidity's `int248` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 248 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt248(int256 value) internal pure returns (int248) {
                          require(value >= type(int248).min && value <= type(int248).max, "SafeCast: value doesn't fit in 248 bits");
                          return int248(value);
                      }
                      /**
                       * @dev Returns the downcasted int240 from int256, reverting on
                       * overflow (when the input is less than smallest int240 or
                       * greater than largest int240).
                       *
                       * Counterpart to Solidity's `int240` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 240 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt240(int256 value) internal pure returns (int240) {
                          require(value >= type(int240).min && value <= type(int240).max, "SafeCast: value doesn't fit in 240 bits");
                          return int240(value);
                      }
                      /**
                       * @dev Returns the downcasted int232 from int256, reverting on
                       * overflow (when the input is less than smallest int232 or
                       * greater than largest int232).
                       *
                       * Counterpart to Solidity's `int232` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 232 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt232(int256 value) internal pure returns (int232) {
                          require(value >= type(int232).min && value <= type(int232).max, "SafeCast: value doesn't fit in 232 bits");
                          return int232(value);
                      }
                      /**
                       * @dev Returns the downcasted int224 from int256, reverting on
                       * overflow (when the input is less than smallest int224 or
                       * greater than largest int224).
                       *
                       * Counterpart to Solidity's `int224` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 224 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt224(int256 value) internal pure returns (int224) {
                          require(value >= type(int224).min && value <= type(int224).max, "SafeCast: value doesn't fit in 224 bits");
                          return int224(value);
                      }
                      /**
                       * @dev Returns the downcasted int216 from int256, reverting on
                       * overflow (when the input is less than smallest int216 or
                       * greater than largest int216).
                       *
                       * Counterpart to Solidity's `int216` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 216 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt216(int256 value) internal pure returns (int216) {
                          require(value >= type(int216).min && value <= type(int216).max, "SafeCast: value doesn't fit in 216 bits");
                          return int216(value);
                      }
                      /**
                       * @dev Returns the downcasted int208 from int256, reverting on
                       * overflow (when the input is less than smallest int208 or
                       * greater than largest int208).
                       *
                       * Counterpart to Solidity's `int208` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 208 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt208(int256 value) internal pure returns (int208) {
                          require(value >= type(int208).min && value <= type(int208).max, "SafeCast: value doesn't fit in 208 bits");
                          return int208(value);
                      }
                      /**
                       * @dev Returns the downcasted int200 from int256, reverting on
                       * overflow (when the input is less than smallest int200 or
                       * greater than largest int200).
                       *
                       * Counterpart to Solidity's `int200` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 200 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt200(int256 value) internal pure returns (int200) {
                          require(value >= type(int200).min && value <= type(int200).max, "SafeCast: value doesn't fit in 200 bits");
                          return int200(value);
                      }
                      /**
                       * @dev Returns the downcasted int192 from int256, reverting on
                       * overflow (when the input is less than smallest int192 or
                       * greater than largest int192).
                       *
                       * Counterpart to Solidity's `int192` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 192 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt192(int256 value) internal pure returns (int192) {
                          require(value >= type(int192).min && value <= type(int192).max, "SafeCast: value doesn't fit in 192 bits");
                          return int192(value);
                      }
                      /**
                       * @dev Returns the downcasted int184 from int256, reverting on
                       * overflow (when the input is less than smallest int184 or
                       * greater than largest int184).
                       *
                       * Counterpart to Solidity's `int184` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 184 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt184(int256 value) internal pure returns (int184) {
                          require(value >= type(int184).min && value <= type(int184).max, "SafeCast: value doesn't fit in 184 bits");
                          return int184(value);
                      }
                      /**
                       * @dev Returns the downcasted int176 from int256, reverting on
                       * overflow (when the input is less than smallest int176 or
                       * greater than largest int176).
                       *
                       * Counterpart to Solidity's `int176` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 176 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt176(int256 value) internal pure returns (int176) {
                          require(value >= type(int176).min && value <= type(int176).max, "SafeCast: value doesn't fit in 176 bits");
                          return int176(value);
                      }
                      /**
                       * @dev Returns the downcasted int168 from int256, reverting on
                       * overflow (when the input is less than smallest int168 or
                       * greater than largest int168).
                       *
                       * Counterpart to Solidity's `int168` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 168 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt168(int256 value) internal pure returns (int168) {
                          require(value >= type(int168).min && value <= type(int168).max, "SafeCast: value doesn't fit in 168 bits");
                          return int168(value);
                      }
                      /**
                       * @dev Returns the downcasted int160 from int256, reverting on
                       * overflow (when the input is less than smallest int160 or
                       * greater than largest int160).
                       *
                       * Counterpart to Solidity's `int160` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 160 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt160(int256 value) internal pure returns (int160) {
                          require(value >= type(int160).min && value <= type(int160).max, "SafeCast: value doesn't fit in 160 bits");
                          return int160(value);
                      }
                      /**
                       * @dev Returns the downcasted int152 from int256, reverting on
                       * overflow (when the input is less than smallest int152 or
                       * greater than largest int152).
                       *
                       * Counterpart to Solidity's `int152` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 152 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt152(int256 value) internal pure returns (int152) {
                          require(value >= type(int152).min && value <= type(int152).max, "SafeCast: value doesn't fit in 152 bits");
                          return int152(value);
                      }
                      /**
                       * @dev Returns the downcasted int144 from int256, reverting on
                       * overflow (when the input is less than smallest int144 or
                       * greater than largest int144).
                       *
                       * Counterpart to Solidity's `int144` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 144 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt144(int256 value) internal pure returns (int144) {
                          require(value >= type(int144).min && value <= type(int144).max, "SafeCast: value doesn't fit in 144 bits");
                          return int144(value);
                      }
                      /**
                       * @dev Returns the downcasted int136 from int256, reverting on
                       * overflow (when the input is less than smallest int136 or
                       * greater than largest int136).
                       *
                       * Counterpart to Solidity's `int136` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 136 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt136(int256 value) internal pure returns (int136) {
                          require(value >= type(int136).min && value <= type(int136).max, "SafeCast: value doesn't fit in 136 bits");
                          return int136(value);
                      }
                      /**
                       * @dev Returns the downcasted int128 from int256, reverting on
                       * overflow (when the input is less than smallest int128 or
                       * greater than largest int128).
                       *
                       * Counterpart to Solidity's `int128` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 128 bits
                       *
                       * _Available since v3.1._
                       */
                      function toInt128(int256 value) internal pure returns (int128) {
                          require(value >= type(int128).min && value <= type(int128).max, "SafeCast: value doesn't fit in 128 bits");
                          return int128(value);
                      }
                      /**
                       * @dev Returns the downcasted int120 from int256, reverting on
                       * overflow (when the input is less than smallest int120 or
                       * greater than largest int120).
                       *
                       * Counterpart to Solidity's `int120` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 120 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt120(int256 value) internal pure returns (int120) {
                          require(value >= type(int120).min && value <= type(int120).max, "SafeCast: value doesn't fit in 120 bits");
                          return int120(value);
                      }
                      /**
                       * @dev Returns the downcasted int112 from int256, reverting on
                       * overflow (when the input is less than smallest int112 or
                       * greater than largest int112).
                       *
                       * Counterpart to Solidity's `int112` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 112 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt112(int256 value) internal pure returns (int112) {
                          require(value >= type(int112).min && value <= type(int112).max, "SafeCast: value doesn't fit in 112 bits");
                          return int112(value);
                      }
                      /**
                       * @dev Returns the downcasted int104 from int256, reverting on
                       * overflow (when the input is less than smallest int104 or
                       * greater than largest int104).
                       *
                       * Counterpart to Solidity's `int104` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 104 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt104(int256 value) internal pure returns (int104) {
                          require(value >= type(int104).min && value <= type(int104).max, "SafeCast: value doesn't fit in 104 bits");
                          return int104(value);
                      }
                      /**
                       * @dev Returns the downcasted int96 from int256, reverting on
                       * overflow (when the input is less than smallest int96 or
                       * greater than largest int96).
                       *
                       * Counterpart to Solidity's `int96` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 96 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt96(int256 value) internal pure returns (int96) {
                          require(value >= type(int96).min && value <= type(int96).max, "SafeCast: value doesn't fit in 96 bits");
                          return int96(value);
                      }
                      /**
                       * @dev Returns the downcasted int88 from int256, reverting on
                       * overflow (when the input is less than smallest int88 or
                       * greater than largest int88).
                       *
                       * Counterpart to Solidity's `int88` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 88 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt88(int256 value) internal pure returns (int88) {
                          require(value >= type(int88).min && value <= type(int88).max, "SafeCast: value doesn't fit in 88 bits");
                          return int88(value);
                      }
                      /**
                       * @dev Returns the downcasted int80 from int256, reverting on
                       * overflow (when the input is less than smallest int80 or
                       * greater than largest int80).
                       *
                       * Counterpart to Solidity's `int80` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 80 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt80(int256 value) internal pure returns (int80) {
                          require(value >= type(int80).min && value <= type(int80).max, "SafeCast: value doesn't fit in 80 bits");
                          return int80(value);
                      }
                      /**
                       * @dev Returns the downcasted int72 from int256, reverting on
                       * overflow (when the input is less than smallest int72 or
                       * greater than largest int72).
                       *
                       * Counterpart to Solidity's `int72` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 72 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt72(int256 value) internal pure returns (int72) {
                          require(value >= type(int72).min && value <= type(int72).max, "SafeCast: value doesn't fit in 72 bits");
                          return int72(value);
                      }
                      /**
                       * @dev Returns the downcasted int64 from int256, reverting on
                       * overflow (when the input is less than smallest int64 or
                       * greater than largest int64).
                       *
                       * Counterpart to Solidity's `int64` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 64 bits
                       *
                       * _Available since v3.1._
                       */
                      function toInt64(int256 value) internal pure returns (int64) {
                          require(value >= type(int64).min && value <= type(int64).max, "SafeCast: value doesn't fit in 64 bits");
                          return int64(value);
                      }
                      /**
                       * @dev Returns the downcasted int56 from int256, reverting on
                       * overflow (when the input is less than smallest int56 or
                       * greater than largest int56).
                       *
                       * Counterpart to Solidity's `int56` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 56 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt56(int256 value) internal pure returns (int56) {
                          require(value >= type(int56).min && value <= type(int56).max, "SafeCast: value doesn't fit in 56 bits");
                          return int56(value);
                      }
                      /**
                       * @dev Returns the downcasted int48 from int256, reverting on
                       * overflow (when the input is less than smallest int48 or
                       * greater than largest int48).
                       *
                       * Counterpart to Solidity's `int48` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 48 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt48(int256 value) internal pure returns (int48) {
                          require(value >= type(int48).min && value <= type(int48).max, "SafeCast: value doesn't fit in 48 bits");
                          return int48(value);
                      }
                      /**
                       * @dev Returns the downcasted int40 from int256, reverting on
                       * overflow (when the input is less than smallest int40 or
                       * greater than largest int40).
                       *
                       * Counterpart to Solidity's `int40` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 40 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt40(int256 value) internal pure returns (int40) {
                          require(value >= type(int40).min && value <= type(int40).max, "SafeCast: value doesn't fit in 40 bits");
                          return int40(value);
                      }
                      /**
                       * @dev Returns the downcasted int32 from int256, reverting on
                       * overflow (when the input is less than smallest int32 or
                       * greater than largest int32).
                       *
                       * Counterpart to Solidity's `int32` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 32 bits
                       *
                       * _Available since v3.1._
                       */
                      function toInt32(int256 value) internal pure returns (int32) {
                          require(value >= type(int32).min && value <= type(int32).max, "SafeCast: value doesn't fit in 32 bits");
                          return int32(value);
                      }
                      /**
                       * @dev Returns the downcasted int24 from int256, reverting on
                       * overflow (when the input is less than smallest int24 or
                       * greater than largest int24).
                       *
                       * Counterpart to Solidity's `int24` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 24 bits
                       *
                       * _Available since v4.7._
                       */
                      function toInt24(int256 value) internal pure returns (int24) {
                          require(value >= type(int24).min && value <= type(int24).max, "SafeCast: value doesn't fit in 24 bits");
                          return int24(value);
                      }
                      /**
                       * @dev Returns the downcasted int16 from int256, reverting on
                       * overflow (when the input is less than smallest int16 or
                       * greater than largest int16).
                       *
                       * Counterpart to Solidity's `int16` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 16 bits
                       *
                       * _Available since v3.1._
                       */
                      function toInt16(int256 value) internal pure returns (int16) {
                          require(value >= type(int16).min && value <= type(int16).max, "SafeCast: value doesn't fit in 16 bits");
                          return int16(value);
                      }
                      /**
                       * @dev Returns the downcasted int8 from int256, reverting on
                       * overflow (when the input is less than smallest int8 or
                       * greater than largest int8).
                       *
                       * Counterpart to Solidity's `int8` operator.
                       *
                       * Requirements:
                       *
                       * - input must fit into 8 bits
                       *
                       * _Available since v3.1._
                       */
                      function toInt8(int256 value) internal pure returns (int8) {
                          require(value >= type(int8).min && value <= type(int8).max, "SafeCast: value doesn't fit in 8 bits");
                          return int8(value);
                      }
                      /**
                       * @dev Converts an unsigned uint256 into a signed int256.
                       *
                       * Requirements:
                       *
                       * - input must be less than or equal to maxInt256.
                       *
                       * _Available since v3.0._
                       */
                      function toInt256(uint256 value) internal pure returns (int256) {
                          // Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
                          require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
                          return int256(value);
                      }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  import "./SafeMath.sol";
                  import "./Address.sol";
                  import "./RevertReasonForwarder.sol";
                  import "../interfaces/IERC20.sol";
                  import "../interfaces/IERC20Permit.sol";
                  import "../interfaces/IDaiLikePermit.sol";
                  // File @1inch/solidity-utils/contracts/libraries/[email protected]
                  library SafeERC20 {
                      error SafeTransferFailed();
                      error SafeTransferFromFailed();
                      error ForceApproveFailed();
                      error SafeIncreaseAllowanceFailed();
                      error SafeDecreaseAllowanceFailed();
                      error SafePermitBadLength();
                      // Ensures method do not revert or return boolean `true`, admits call to non-smart-contract
                      function safeTransferFrom(IERC20 token, address from, address to, uint256 amount) internal {
                          bytes4 selector = token.transferFrom.selector;
                          bool success;
                          /// @solidity memory-safe-assembly
                          assembly { // solhint-disable-line no-inline-assembly
                              let data := mload(0x40)
                              mstore(data, selector)
                              mstore(add(data, 0x04), from)
                              mstore(add(data, 0x24), to)
                              mstore(add(data, 0x44), amount)
                              success := call(gas(), token, 0, data, 100, 0x0, 0x20)
                              if success {
                                  switch returndatasize()
                                  case 0 { success := gt(extcodesize(token), 0) }
                                  default { success := and(gt(returndatasize(), 31), eq(mload(0), 1)) }
                              }
                          }
                          if (!success) revert SafeTransferFromFailed();
                      }
                      // Ensures method do not revert or return boolean `true`, admits call to non-smart-contract
                      function safeTransfer(IERC20 token, address to, uint256 value) internal {
                          if (!_makeCall(token, token.transfer.selector, to, value)) {
                              revert SafeTransferFailed();
                          }
                      }
                      function safeApprove(IERC20 token, address spender, uint256 value) internal {
                          forceApprove(token, spender, value);
                      }
                      // If `approve(from, to, amount)` fails, try to `approve(from, to, 0)` before retry
                      function forceApprove(IERC20 token, address spender, uint256 value) internal {
                          if (!_makeCall(token, token.approve.selector, spender, value)) {
                              if (!_makeCall(token, token.approve.selector, spender, 0) ||
                                  !_makeCall(token, token.approve.selector, spender, value))
                              {
                                  revert ForceApproveFailed();
                              }
                          }
                      }
                      
                      function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                          uint256 allowance = token.allowance(address(this), spender);
                          if (value > type(uint256).max - allowance) revert SafeIncreaseAllowanceFailed();
                          forceApprove(token, spender, allowance + value);
                      }
                      function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
                          uint256 allowance = token.allowance(address(this), spender);
                          if (value > allowance) revert SafeDecreaseAllowanceFailed();
                          forceApprove(token, spender, allowance - value);
                      }
                      function safePermit(IERC20 token, bytes calldata permit) internal {
                          bool success;
                          if (permit.length == 32 * 7) {
                              success = _makeCalldataCall(token, IERC20Permit.permit.selector, permit);
                          } else if (permit.length == 32 * 8) {
                              success = _makeCalldataCall(token, IDaiLikePermit.permit.selector, permit);
                          } else {
                              revert SafePermitBadLength();
                          }
                          if (!success) RevertReasonForwarder.reRevert();
                      }
                      function _makeCall(IERC20 token, bytes4 selector, address to, uint256 amount) private returns(bool success) {
                          /// @solidity memory-safe-assembly
                          assembly { // solhint-disable-line no-inline-assembly
                              let data := mload(0x40)
                              mstore(data, selector)
                              mstore(add(data, 0x04), to)
                              mstore(add(data, 0x24), amount)
                              success := call(gas(), token, 0, data, 0x44, 0x0, 0x20)
                              if success {
                                  switch returndatasize()
                                  case 0 { success := gt(extcodesize(token), 0) }
                                  default { success := and(gt(returndatasize(), 31), eq(mload(0), 1)) }
                              }
                          }
                      }
                      function _makeCalldataCall(IERC20 token, bytes4 selector, bytes calldata args) private returns(bool success) {
                          /// @solidity memory-safe-assembly
                          assembly { // solhint-disable-line no-inline-assembly
                              let len := add(4, args.length)
                              let data := mload(0x40)
                              mstore(data, selector)
                              calldatacopy(add(data, 0x04), args.offset, args.length)
                              success := call(gas(), token, 0, data, len, 0x0, 0x20)
                              if success {
                                  switch returndatasize()
                                  case 0 { success := gt(extcodesize(token), 0) }
                                  default { success := and(gt(returndatasize(), 31), eq(mload(0), 1)) }
                              }
                          }
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  library SafeMath {
                      uint256 constant WAD = 10**18;
                      uint256 constant RAY = 10**27;
                      function wad() public pure returns (uint256) {
                          return WAD;
                      }
                      function ray() public pure returns (uint256) {
                          return RAY;
                      }
                      function add(uint256 a, uint256 b) internal pure returns (uint256) {
                          uint256 c = a + b;
                          require(c >= a, "SafeMath: addition overflow");
                          return c;
                      }
                      function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                          return sub(a, b, "SafeMath: subtraction overflow");
                      }
                      function sub(
                          uint256 a,
                          uint256 b,
                          string memory errorMessage
                      ) internal pure returns (uint256) {
                          require(b <= a, errorMessage);
                          uint256 c = a - b;
                          return c;
                      }
                      function mul(uint256 a, uint256 b) internal pure returns (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 0;
                          }
                          uint256 c = a * b;
                          require(c / a == b, "SafeMath: multiplication overflow");
                          return c;
                      }
                      function div(uint256 a, uint256 b) internal pure returns (uint256) {
                          return div(a, b, "SafeMath: division by zero");
                      }
                      function div(
                          uint256 a,
                          uint256 b,
                          string memory errorMessage
                      ) internal pure returns (uint256) {
                          // Solidity only automatically asserts when dividing by 0
                          require(b > 0, errorMessage);
                          uint256 c = a / b;
                          // assert(a == b * c + a % b); // There is no case in which this doesn't hold
                          return c;
                      }
                      function mod(uint256 a, uint256 b) internal pure returns (uint256) {
                          return mod(a, b, "SafeMath: modulo by zero");
                      }
                      function mod(
                          uint256 a,
                          uint256 b,
                          string memory errorMessage
                      ) internal pure returns (uint256) {
                          require(b != 0, errorMessage);
                          return a % b;
                      }
                      function min(uint256 a, uint256 b) internal pure returns (uint256) {
                          return a <= b ? a : b;
                      }
                      function max(uint256 a, uint256 b) internal pure returns (uint256) {
                          return a >= b ? a : b;
                      }
                      function sqrt(uint256 a) internal pure returns (uint256 b) {
                          if (a > 3) {
                              b = a;
                              uint256 x = a / 2 + 1;
                              while (x < b) {
                                  b = x;
                                  x = (a / x + x) / 2;
                              }
                          } else if (a != 0) {
                              b = 1;
                          }
                      }
                      function wmul(uint256 a, uint256 b) internal pure returns (uint256) {
                          return mul(a, b) / WAD;
                      }
                      function wmulRound(uint256 a, uint256 b) internal pure returns (uint256) {
                          return add(mul(a, b), WAD / 2) / WAD;
                      }
                      function rmul(uint256 a, uint256 b) internal pure returns (uint256) {
                          return mul(a, b) / RAY;
                      }
                      function rmulRound(uint256 a, uint256 b) internal pure returns (uint256) {
                          return add(mul(a, b), RAY / 2) / RAY;
                      }
                      function wdiv(uint256 a, uint256 b) internal pure returns (uint256) {
                          return div(mul(a, WAD), b);
                      }
                      function wdivRound(uint256 a, uint256 b) internal pure returns (uint256) {
                          return add(mul(a, WAD), b / 2) / b;
                      }
                      function rdiv(uint256 a, uint256 b) internal pure returns (uint256) {
                          return div(mul(a, RAY), b);
                      }
                      function rdivRound(uint256 a, uint256 b) internal pure returns (uint256) {
                          return add(mul(a, RAY), b / 2) / b;
                      }
                      function wpow(uint256 x, uint256 n) internal pure returns (uint256) {
                          uint256 result = WAD;
                          while (n > 0) {
                              if (n % 2 != 0) {
                                  result = wmul(result, x);
                              }
                              x = wmul(x, x);
                              n /= 2;
                          }
                          return result;
                      }
                      function rpow(uint256 x, uint256 n) internal pure returns (uint256) {
                          uint256 result = RAY;
                          while (n > 0) {
                              if (n % 2 != 0) {
                                  result = rmul(result, x);
                              }
                              x = rmul(x, x);
                              n /= 2;
                          }
                          return result;
                      }
                      function divCeil(uint256 a, uint256 b) internal pure returns (uint256) {
                          uint256 quotient = div(a, b);
                          uint256 remainder = a - quotient * b;
                          if (remainder > 0) {
                              return quotient + 1;
                          } else {
                              return quotient;
                          }
                      }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  import {SafeMath} from "./SafeMath.sol";
                  import {IERC20} from "../interfaces/IERC20.sol";
                  import {SafeERC20} from "./SafeERC20.sol";
                  library UniversalERC20 {
                      using SafeMath for uint256;
                      using SafeERC20 for IERC20;
                      IERC20 private constant ETH_ADDRESS =
                          IERC20(0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE);
                      function universalTransfer(
                          IERC20 token,
                          address payable to,
                          uint256 amount
                      ) internal {
                          if (amount > 0) {
                              if (isETH(token)) {
                                  to.transfer(amount);
                              } else {
                                  token.safeTransfer(to, amount);
                              }
                          }
                      }
                      function universalTransferFrom(
                          IERC20 token,
                          address from,
                          address payable to,
                          uint256 amount
                      ) internal {
                          if (amount > 0) {
                              token.safeTransferFrom(from, to, amount);
                          }
                      }
                      function universalApproveMax(
                          IERC20 token,
                          address to,
                          uint256 amount
                      ) internal {
                          uint256 allowance = token.allowance(address(this), to);
                          if (allowance < amount) {
                              token.forceApprove(to, type(uint256).max);
                          }
                      }
                      function universalBalanceOf(IERC20 token, address who)
                          internal
                          view
                          returns (uint256)
                      {
                          if (isETH(token)) {
                              return who.balance;
                          } else {
                              return token.balanceOf(who);
                          }
                      }
                      function tokenBalanceOf(IERC20 token, address who)
                          internal
                          view
                          returns (uint256)
                      {
                          return token.balanceOf(who);
                      }
                      function isETH(IERC20 token) internal pure returns (bool) {
                          return token == ETH_ADDRESS;
                      }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  import "../libraries/CommonUtils.sol";
                  import "../libraries/SafeERC20.sol";
                  import "../interfaces/IWETH.sol";
                  import "../interfaces/IWNativeRelayer.sol";
                  import "../interfaces/IERC20.sol";
                  import "../interfaces/IApproveProxy.sol";
                  /// @title Base contract with common payable logics
                  abstract contract WrapETHSwap is CommonUtils {
                    uint256 private constant SWAP_AMOUNT = 0x00000000000000000000000000000000ffffffffffffffffffffffffffffffff;
                    
                    function swapWrap(uint256 orderId, uint256 rawdata) external payable {
                      bool reversed;
                      uint128 amount;
                      assembly {
                        reversed := and(rawdata, _REVERSE_MASK)
                        amount := and(rawdata, SWAP_AMOUNT)
                      }
                      require(amount > 0, "amount must be > 0");
                      if (reversed) {
                        IApproveProxy(_APPROVE_PROXY).claimTokens(_WETH, msg.sender, _WNATIVE_RELAY, amount);
                        IWNativeRelayer(_WNATIVE_RELAY).withdraw(amount);
                        (bool success, ) = payable(msg.sender).call{value: address(this).balance}("");
                        require(success, "transfer native token failed");
                      } else {
                        require(msg.value == amount, "value not equal amount");
                        IWETH(_WETH).deposit{value: amount}();
                        SafeERC20.safeTransfer(IERC20(_WETH), msg.sender, amount);
                      }
                      emit SwapOrderId(orderId);
                      emit OrderRecord(reversed ? _WETH : _ETH, reversed ? _ETH: _WETH, msg.sender, amount, amount);
                    }
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  contract DexRouterStorage {
                      // In the test scenario, we take it as a settable state and adjust it to a constant after it stabilizes
                      address public approveProxy;
                      address public wNativeRelayer;
                      mapping(address => bool) public priorityAddresses;
                      uint256[19] internal _dexRouterGap;
                      address public admin;
                  }
                  // SPDX-License-Identifier: MIT
                  pragma solidity ^0.8.0;
                  import "./interfaces/IUni.sol";
                  import "./libraries/UniversalERC20.sol";
                  import "./libraries/CommonUtils.sol";
                  contract UnxswapRouter is CommonUtils {
                      uint256 private constant _IS_TOKEN0_TAX =
                          0x1000000000000000000000000000000000000000000000000000000000000000;
                      uint256 private constant _IS_TOKEN1_TAX =
                          0x2000000000000000000000000000000000000000000000000000000000000000;
                      uint256 private constant _CLAIM_TOKENS_CALL_SELECTOR_32 =
                          0x0a5ea46600000000000000000000000000000000000000000000000000000000;
                      uint256 private constant _TRANSFER_DEPOSIT_SELECTOR =
                          0xa9059cbbd0e30db0000000000000000000000000000000000000000000000000;
                      uint256 private constant _SWAP_GETRESERVES_SELECTOR =
                          0x022c0d9f0902f1ac000000000000000000000000000000000000000000000000;
                      uint256 private constant _WITHDRAW_TRNASFER_SELECTOR =
                          0x2e1a7d4da9059cbb000000000000000000000000000000000000000000000000;
                      uint256 private constant _BALANCEOF_TOKEN0_SELECTOR =
                          0x70a082310dfe1681000000000000000000000000000000000000000000000000;
                      uint256 private constant _BALANCEOF_TOKEN1_SELECTOR =
                          0x70a08231d21220a7000000000000000000000000000000000000000000000000;
                      uint256 private constant _WETH_MASK =
                          0x4000000000000000000000000000000000000000000000000000000000000000;
                      uint256 private constant _NUMERATOR_MASK =
                          0x0000000000000000ffffffff0000000000000000000000000000000000000000;
                      uint256 private constant _DENOMINATOR = 1_000_000_000;
                      uint256 private constant _NUMERATOR_OFFSET = 160;
                      uint256 private constant ETH_ADDRESS = 0x00;
                      //-------------------------------
                      //------- Internal Functions ----
                      //-------------------------------
                      /// @notice Performs the internal logic for executing a swap using the Unxswap protocol.
                      /// @param srcToken The token to be swapped.
                      /// @param amount The amount of the source token to be swapped.
                      /// @param minReturn The minimum amount of tokens that must be received for the swap to be valid, protecting against slippage.
                      /// @param pools The array of pool identifiers that define the swap route.
                      /// @param payer The address of the entity providing the source tokens for the swap.
                      /// @param receiver The address that will receive the tokens after the swap.
                      /// @return returnAmount The amount of tokens received from the swap.
                      /// @dev This internal function encapsulates the core logic of the Unxswap token swap process. It is meant to be called by other external functions that set up the required parameters. The actual interaction with the Unxswap pools and the token transfer mechanics are implemented here.
                      function _unxswapInternal(
                          IERC20 srcToken,
                          uint256 amount,
                          uint256 minReturn,
                          // solhint-disable-next-line no-unused-vars
                          bytes32[] calldata pools,
                          address payer,
                          address receiver
                      ) internal returns (uint256 returnAmount) {
                          assembly {
                              // solhint-disable-line no-inline-assembly
                              function revertWithReason(m, len) {
                                  mstore(
                                      0,
                                      0x08c379a000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(
                                      0x20,
                                      0x0000002000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(0x40, m)
                                  revert(0, len)
                              }
                              function _getTokenAddr(emptyPtr, pair, selector) -> token {
                                  mstore(emptyPtr, selector)
                                  if iszero(
                                      staticcall(
                                          gas(),
                                          pair,
                                          add(0x04, emptyPtr),
                                          0x04,
                                          0x00,
                                          0x20
                                      )
                                  ) {
                                      revertWithReason(
                                          0x0000001067657420746f6b656e206661696c6564000000000000000000000000,
                                          0x54
                                      ) // "get token failed"
                                  }
                                  token := mload(0x00)
                              }
                              function _getBalanceOfToken0(emptyPtr, pair) -> token0, balance0 {
                                  mstore(emptyPtr, _BALANCEOF_TOKEN0_SELECTOR)
                                  if iszero(
                                      staticcall(
                                          gas(),
                                          pair,
                                          add(0x04, emptyPtr),
                                          0x04,
                                          0x00,
                                          0x20
                                      )
                                  ) {
                                      revertWithReason(
                                          0x00000012746f6b656e302063616c6c206661696c656400000000000000000000,
                                          0x56
                                      ) // "token0 call failed"
                                  }
                                  token0 := mload(0x00)
                                  mstore(add(0x04, emptyPtr), pair)
                                  if iszero(
                                      staticcall(gas(), token0, emptyPtr, 0x24, 0x00, 0x20)
                                  ) {
                                      revertWithReason(
                                          0x0000001562616c616e63654f662063616c6c206661696c656400000000000000,
                                          0x59
                                      ) // "balanceOf call failed"
                                  }
                                  balance0 := mload(0x00)
                              }
                              function _getBalanceOfToken1(emptyPtr, pair) -> token1, balance1 {
                                  mstore(emptyPtr, _BALANCEOF_TOKEN1_SELECTOR)
                                  if iszero(
                                      staticcall(
                                          gas(),
                                          pair,
                                          add(0x04, emptyPtr),
                                          0x04,
                                          0x00,
                                          0x20
                                      )
                                  ) {
                                      revertWithReason(
                                          0x00000012746f6b656e312063616c6c206661696c656400000000000000000000,
                                          0x56
                                      ) // "token1 call failed"
                                  }
                                  token1 := mload(0x00)
                                  mstore(add(0x04, emptyPtr), pair)
                                  if iszero(
                                      staticcall(gas(), token1, emptyPtr, 0x24, 0x00, 0x20)
                                  ) {
                                      revertWithReason(
                                          0x0000001562616c616e63654f662063616c6c206661696c656400000000000000,
                                          0x59
                                      ) // "balanceOf call failed"
                                  }
                                  balance1 := mload(0x00)
                              }
                              function swap(
                                  emptyPtr,
                                  swapAmount,
                                  pair,
                                  reversed,
                                  isToken0Tax,
                                  isToken1Tax,
                                  numerator,
                                  dst
                              ) -> ret {
                                  mstore(emptyPtr, _SWAP_GETRESERVES_SELECTOR)
                                  if iszero(
                                      staticcall(
                                          gas(),
                                          pair,
                                          add(0x04, emptyPtr),
                                          0x4,
                                          0x00,
                                          0x40
                                      )
                                  ) {
                                      // we only need the first 0x40 bytes, no need timestamp info
                                      revertWithReason(
                                          0x0000001472657365727665732063616c6c206661696c65640000000000000000,
                                          0x58
                                      ) // "reserves call failed"
                                  }
                                  let reserve0 := mload(0x00)
                                  let reserve1 := mload(0x20)
                                  switch reversed
                                  case 0 {
                                      //swap token0 for token1
                                      if isToken0Tax {
                                          let token0, balance0 := _getBalanceOfToken0(
                                              emptyPtr,
                                              pair
                                          )
                                          swapAmount := sub(balance0, reserve0)
                                      }
                                  }
                                  default {
                                      //swap token1 for token0
                                      if isToken1Tax {
                                          let token1, balance1 := _getBalanceOfToken1(
                                              emptyPtr,
                                              pair
                                          )
                                          swapAmount := sub(balance1, reserve1)
                                      }
                                      let temp := reserve0
                                      reserve0 := reserve1
                                      reserve1 := temp
                                  }
                                  ret := mul(swapAmount, numerator)
                                  ret := div(
                                      mul(ret, reserve1),
                                      add(ret, mul(reserve0, _DENOMINATOR))
                                  )
                                  mstore(emptyPtr, _SWAP_GETRESERVES_SELECTOR)
                                  switch reversed
                                  case 0 {
                                      mstore(add(emptyPtr, 0x04), 0)
                                      mstore(add(emptyPtr, 0x24), ret)
                                  }
                                  default {
                                      mstore(add(emptyPtr, 0x04), ret)
                                      mstore(add(emptyPtr, 0x24), 0)
                                  }
                                  mstore(add(emptyPtr, 0x44), dst)
                                  mstore(add(emptyPtr, 0x64), 0x80)
                                  mstore(add(emptyPtr, 0x84), 0)
                                  if iszero(call(gas(), pair, 0, emptyPtr, 0xa4, 0, 0)) {
                                      revertWithReason(
                                          0x00000010737761702063616c6c206661696c6564000000000000000000000000,
                                          0x54
                                      ) // "swap call failed"
                                  }
                              }
                              let poolsOffset
                              let poolsEndOffset
                              {
                                  let len := pools.length
                                  poolsOffset := pools.offset //
                                  poolsEndOffset := add(poolsOffset, mul(len, 32))
                                  if eq(len, 0) {
                                      revertWithReason(
                                          0x000000b656d70747920706f6f6c73000000000000000000000000000000000000,
                                          0x4e
                                      ) // "empty pools"
                                  }
                              }
                              let emptyPtr := mload(0x40)
                              let rawPair := calldataload(poolsOffset)
                              switch eq(ETH_ADDRESS, srcToken)
                              case 1 {
                                  // require callvalue() >= amount, lt: if x < y return 1,else return 0
                                  if eq(lt(callvalue(), amount), 1) {
                                      revertWithReason(
                                          0x00000011696e76616c6964206d73672e76616c75650000000000000000000000,
                                          0x55
                                      ) // "invalid msg.value"
                                  }
                                  mstore(emptyPtr, _TRANSFER_DEPOSIT_SELECTOR)
                                  if iszero(
                                      call(gas(), _WETH, amount, add(emptyPtr, 0x04), 0x4, 0, 0)
                                  ) {
                                      revertWithReason(
                                          0x000000126465706f73697420455448206661696c656400000000000000000000,
                                          0x56
                                      ) // "deposit ETH failed"
                                  }
                                  mstore(add(0x04, emptyPtr), and(rawPair, _ADDRESS_MASK))
                                  mstore(add(0x24, emptyPtr), amount)
                                  if iszero(call(gas(), _WETH, 0, emptyPtr, 0x44, 0, 0x20)) {
                                      revertWithReason(
                                          0x000000147472616e736665722057455448206661696c65640000000000000000,
                                          0x58
                                      ) // "transfer WETH failed"
                                  }
                              }
                              default {
                                  if callvalue() {
                                      revertWithReason(
                                          0x00000011696e76616c6964206d73672e76616c75650000000000000000000000,
                                          0x55
                                      ) // "invalid msg.value"
                                  }
                                  mstore(emptyPtr, _CLAIM_TOKENS_CALL_SELECTOR_32)
                                  mstore(add(emptyPtr, 0x4), srcToken)
                                  mstore(add(emptyPtr, 0x24), payer)
                                  mstore(add(emptyPtr, 0x44), and(rawPair, _ADDRESS_MASK))
                                  mstore(add(emptyPtr, 0x64), amount)
                                  if iszero(
                                      call(gas(), _APPROVE_PROXY, 0, emptyPtr, 0x84, 0, 0)
                                  ) {
                                      revertWithReason(
                                          0x00000012636c61696d20746f6b656e206661696c656400000000000000000000,
                                          0x56
                                      ) // "claim token failed"
                                  }
                              }
                              returnAmount := amount
                              for {
                                  let i := add(poolsOffset, 0x20)
                              } lt(i, poolsEndOffset) {
                                  i := add(i, 0x20)
                              } {
                                  let nextRawPair := calldataload(i)
                                  returnAmount := swap(
                                      emptyPtr,
                                      returnAmount,
                                      and(rawPair, _ADDRESS_MASK),
                                      and(rawPair, _REVERSE_MASK),
                                      and(rawPair, _IS_TOKEN0_TAX),
                                      and(rawPair, _IS_TOKEN1_TAX),
                                      shr(_NUMERATOR_OFFSET, and(rawPair, _NUMERATOR_MASK)),
                                      and(nextRawPair, _ADDRESS_MASK)
                                  )
                                  rawPair := nextRawPair
                              }
                              let toToken
                              switch and(rawPair, _WETH_MASK)
                              case 0 {
                                  let beforeAmount
                                  switch and(rawPair, _REVERSE_MASK)
                                  case 0 {
                                      if and(rawPair, _IS_TOKEN1_TAX) {
                                          mstore(emptyPtr, _BALANCEOF_TOKEN1_SELECTOR)
                                          if iszero(
                                              staticcall(
                                                  gas(),
                                                  and(rawPair, _ADDRESS_MASK),
                                                  add(0x04, emptyPtr),
                                                  0x04,
                                                  0x00,
                                                  0x20
                                              )
                                          ) {
                                              revertWithReason(
                                                  0x00000012746f6b656e312063616c6c206661696c656400000000000000000000,
                                                  0x56
                                              ) // "token1 call failed"
                                          }
                                          toToken := mload(0)
                                          mstore(add(0x04, emptyPtr), receiver)
                                          if iszero(
                                              staticcall(
                                                  gas(),
                                                  toToken,
                                                  emptyPtr,
                                                  0x24,
                                                  0x00,
                                                  0x20
                                              )
                                          ) {
                                              revertWithReason(
                                                  0x00000015746f6b656e312062616c616e6365206661696c656400000000000000,
                                                  0x59
                                              ) // "token1 balance failed"
                                          }
                                          beforeAmount := mload(0)
                                      }
                                  }
                                  default {
                                      if and(rawPair, _IS_TOKEN0_TAX) {
                                          mstore(emptyPtr, _BALANCEOF_TOKEN0_SELECTOR)
                                          if iszero(
                                              staticcall(
                                                  gas(),
                                                  and(rawPair, _ADDRESS_MASK),
                                                  add(0x04, emptyPtr),
                                                  0x04,
                                                  0x00,
                                                  0x20
                                              )
                                          ) {
                                              revertWithReason(
                                                  0x00000012746f6b656e302063616c6c206661696c656400000000000000000000,
                                                  0x56
                                              ) // "token0 call failed"
                                          }
                                          toToken := mload(0)
                                          mstore(add(0x04, emptyPtr), receiver)
                                          if iszero(
                                              staticcall(
                                                  gas(),
                                                  toToken,
                                                  emptyPtr,
                                                  0x24,
                                                  0x00,
                                                  0x20
                                              )
                                          ) {
                                              revertWithReason(
                                                  0x00000015746f6b656e302062616c616e6365206661696c656400000000000000,
                                                  0x56
                                              ) // "token0 balance failed"
                                          }
                                          beforeAmount := mload(0)
                                      }
                                  }
                                  returnAmount := swap(
                                      emptyPtr,
                                      returnAmount,
                                      and(rawPair, _ADDRESS_MASK),
                                      and(rawPair, _REVERSE_MASK),
                                      and(rawPair, _IS_TOKEN0_TAX),
                                      and(rawPair, _IS_TOKEN1_TAX),
                                      shr(_NUMERATOR_OFFSET, and(rawPair, _NUMERATOR_MASK)),
                                      receiver
                                  )
                                  switch lt(0x0, toToken)
                                  case 1 {
                                      mstore(emptyPtr, _BALANCEOF_TOKEN0_SELECTOR)
                                      mstore(add(0x04, emptyPtr), receiver)
                                      if iszero(
                                          staticcall(gas(), toToken, emptyPtr, 0x24, 0x00, 0x20)
                                      ) {
                                          revertWithReason(
                                              0x000000146765742062616c616e63654f66206661696c65640000000000000000,
                                              0x58
                                          ) // "get balanceOf failed"
                                      }
                                      returnAmount := sub(mload(0), beforeAmount)
                                  }
                                  default {
                                      // set token0 addr for the non-safemoon token
                                      switch and(rawPair, _REVERSE_MASK)
                                      case 0 {
                                          // get token1
                                          toToken := _getTokenAddr(
                                              emptyPtr,
                                              and(rawPair, _ADDRESS_MASK),
                                              _BALANCEOF_TOKEN1_SELECTOR
                                          )
                                      }
                                      default {
                                          // get token0
                                          toToken := _getTokenAddr(
                                              emptyPtr,
                                              and(rawPair, _ADDRESS_MASK),
                                              _BALANCEOF_TOKEN0_SELECTOR
                                          )
                                      }
                                  }
                              }
                              default {
                                  toToken := ETH_ADDRESS
                                  returnAmount := swap(
                                      emptyPtr,
                                      returnAmount,
                                      and(rawPair, _ADDRESS_MASK),
                                      and(rawPair, _REVERSE_MASK),
                                      and(rawPair, _IS_TOKEN0_TAX),
                                      and(rawPair, _IS_TOKEN1_TAX),
                                      shr(_NUMERATOR_OFFSET, and(rawPair, _NUMERATOR_MASK)),
                                      address()
                                  )
                                  mstore(emptyPtr, _WITHDRAW_TRNASFER_SELECTOR)
                                  mstore(add(emptyPtr, 0x08), _WNATIVE_RELAY)
                                  mstore(add(emptyPtr, 0x28), returnAmount)
                                  if iszero(
                                      call(gas(), _WETH, 0, add(0x04, emptyPtr), 0x44, 0, 0x20)
                                  ) {
                                      revertWithReason(
                                          0x000000147472616e736665722057455448206661696c65640000000000000000,
                                          0x58
                                      ) // "transfer WETH failed"
                                  }
                                  mstore(add(emptyPtr, 0x04), returnAmount)
                                  if iszero(
                                      call(gas(), _WNATIVE_RELAY, 0, emptyPtr, 0x24, 0, 0x20)
                                  ) {
                                      revertWithReason(
                                          0x00000013776974686472617720455448206661696c6564000000000000000000,
                                          0x57
                                      ) // "withdraw ETH failed"
                                  }
                                  if iszero(call(gas(), receiver, returnAmount, 0, 0, 0, 0)) {
                                      revertWithReason(
                                          0x000000137472616e7366657220455448206661696c6564000000000000000000,
                                          0x57
                                      ) // "transfer ETH failed"
                                  }
                              }
                              if lt(returnAmount, minReturn) {
                                  revertWithReason(
                                      0x000000164d696e2072657475726e206e6f742072656163686564000000000000,
                                      0x5a
                                  ) // "Min return not reached"
                              }
                              // emit event
                              mstore(emptyPtr, srcToken)
                              mstore(add(emptyPtr, 0x20), toToken)
                              mstore(add(emptyPtr, 0x40), origin())
                              mstore(add(emptyPtr, 0x60), amount)
                              mstore(add(emptyPtr, 0x80), returnAmount)
                              log1(
                                  emptyPtr,
                                  0xa0,
                                  0x1bb43f2da90e35f7b0cf38521ca95a49e68eb42fac49924930a5bd73cdf7576c
                              )
                          }
                      }
                  }
                  /// SPDX-License-Identifier: MIT
                  pragma solidity 0.8.17;
                  import "./interfaces/IUniswapV3SwapCallback.sol";
                  import "./interfaces/IUniV3.sol";
                  import "./interfaces/IWETH.sol";
                  import "./interfaces/IWNativeRelayer.sol";
                  import "./libraries/Address.sol";
                  import "./libraries/CommonUtils.sol";
                  import "./libraries/RouterErrors.sol";
                  import "./libraries/SafeCast.sol";
                  contract UnxswapV3Router is IUniswapV3SwapCallback, CommonUtils {
                      using Address for address payable;
                      uint256 private constant _ONE_FOR_ZERO_MASK = 1 << 255; // Mask for identifying if the swap is one-for-zero
                      uint256 private constant _WETH_UNWRAP_MASK = 1 << 253; // Mask for identifying if WETH should be unwrapped to ETH
                      bytes32 private constant _POOL_INIT_CODE_HASH =
                          0xe34f199b19b2b4f47f68442619d555527d244f78a3297ea89325f843f87b8b54; // Pool init code hash
                      bytes32 private constant _FF_FACTORY =
                          0xff1F98431c8aD98523631AE4a59f267346ea31F9840000000000000000000000; // Factory address
                      // concatenation of token0(), token1() fee(), transfer() and claimTokens() selectors
                      bytes32 private constant _SELECTORS =
                          0x0dfe1681d21220a7ddca3f43a9059cbb0a5ea466000000000000000000000000;
                      // concatenation of withdraw(uint),transfer()
                      bytes32 private constant _SELECTORS2 =
                          0x2e1a7d4da9059cbb000000000000000000000000000000000000000000000000;
                      uint160 private constant _MIN_SQRT_RATIO = 4_295_128_739 + 1;
                      uint160 private constant _MAX_SQRT_RATIO =
                          1_461_446_703_485_210_103_287_273_052_203_988_822_378_723_970_342 - 1;
                      bytes32 private constant _SWAP_SELECTOR =
                          0x128acb0800000000000000000000000000000000000000000000000000000000; // Swap function selector
                      uint256 private constant _INT256_MAX =
                          0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff; // Maximum int256
                      uint256 private constant _INT256_MIN =
                          0x8000000000000000000000000000000000000000000000000000000000000000; // Minimum int256
                      /// @notice Conducts a swap using the Uniswap V3 protocol internally within the contract.
                      /// @param payer The address of the account providing the tokens for the swap.
                      /// @param receiver The address that will receive the tokens after the swap.
                      /// @param amount The amount of the source token to be swapped.
                      /// @param minReturn The minimum amount of tokens that must be received for the swap to be valid, safeguarding against excessive slippage.
                      /// @param pools An array of pool identifiers defining the swap route within Uniswap V3.
                      /// @return returnAmount The amount of tokens received from the swap.
                      /// @return srcTokenAddr The address of the source token used for the swap.
                      /// @dev This internal function encapsulates the core logic for executing swaps on Uniswap V3. It is intended to be used by other functions in the contract that prepare and pass the necessary parameters. The function handles the swapping process, ensuring that the minimum return is met and managing the transfer of tokens.
                      function _uniswapV3Swap(
                          address payer,
                          address payable receiver,
                          uint256 amount,
                          uint256 minReturn,
                          uint256[] calldata pools
                      ) internal returns (uint256 returnAmount, address srcTokenAddr) {
                          assembly {
                              function _revertWithReason(m, len) {
                                  mstore(
                                      0,
                                      0x08c379a000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(
                                      0x20,
                                      0x0000002000000000000000000000000000000000000000000000000000000000
                                  )
                                  mstore(0x40, m)
                                  revert(0, len)
                              }
                              function _makeSwap(_receiver, _payer, _pool, _amount)
                                  -> _returnAmount
                              {
                                  if lt(_INT256_MAX, _amount) {
                                      mstore(
                                          0,
                                          0xb3f79fd000000000000000000000000000000000000000000000000000000000
                                      ) //SafeCastToInt256Failed()
                                      revert(0, 4)
                                  }
                                  let freePtr := mload(0x40)
                                  let zeroForOne := eq(and(_pool, _ONE_FOR_ZERO_MASK), 0)
                                  let poolAddr := and(_pool, _ADDRESS_MASK)
                                  switch zeroForOne
                                  case 1 {
                                      mstore(freePtr, _SWAP_SELECTOR)
                                      let paramPtr := add(freePtr, 4)
                                      mstore(paramPtr, _receiver)
                                      mstore(add(paramPtr, 0x20), true)
                                      mstore(add(paramPtr, 0x40), _amount)
                                      mstore(add(paramPtr, 0x60), _MIN_SQRT_RATIO)
                                      mstore(add(paramPtr, 0x80), 0xa0)
                                      mstore(add(paramPtr, 0xa0), 32)
                                      mstore(add(paramPtr, 0xc0), _payer)
                                      let success := call(gas(), poolAddr, 0, freePtr, 0xe4, 0, 0)
                                      if iszero(success) {
                                          revert(0, 32)
                                      }
                                      returndatacopy(0, 32, 32) // only copy _amount1   MEM[0:] <= RETURNDATA[32:32+32]
                                  }
                                  default {
                                      mstore(freePtr, _SWAP_SELECTOR)
                                      let paramPtr := add(freePtr, 4)
                                      mstore(paramPtr, _receiver)
                                      mstore(add(paramPtr, 0x20), false)
                                      mstore(add(paramPtr, 0x40), _amount)
                                      mstore(add(paramPtr, 0x60), _MAX_SQRT_RATIO)
                                      mstore(add(paramPtr, 0x80), 0xa0)
                                      mstore(add(paramPtr, 0xa0), 32)
                                      mstore(add(paramPtr, 0xc0), _payer)
                                      let success := call(gas(), poolAddr, 0, freePtr, 0xe4, 0, 0)
                                      if iszero(success) {
                                          revert(0, 32)
                                      }
                                      returndatacopy(0, 0, 32) // only copy _amount0   MEM[0:] <= RETURNDATA[0:0+32]
                                  }
                                  _returnAmount := mload(0)
                                  if lt(_returnAmount, _INT256_MIN) {
                                      mstore(
                                          0,
                                          0x88c8ee9c00000000000000000000000000000000000000000000000000000000
                                      ) //SafeCastToUint256Failed()
                                      revert(0, 4)
                                  }
                                  _returnAmount := add(1, not(_returnAmount)) // -a = ~a + 1
                              }
                              function _wrapWeth(_amount) {
                                  // require callvalue() >= amount, lt: if x < y return 1,else return 0
                                  if eq(lt(callvalue(), _amount), 1) {
                                      mstore(
                                          0,
                                          0x1841b4e100000000000000000000000000000000000000000000000000000000
                                      ) // InvalidMsgValue()
                                      revert(0, 4)
                                  }
                                  let success := call(gas(), _WETH, _amount, 0, 0, 0, 0) //进入fallback逻辑
                                  if iszero(success) {
                                      _revertWithReason(
                                          0x0000001357455448206465706f736974206661696c6564000000000000000000,
                                          87
                                      ) //WETH deposit failed
                                  }
                              }
                              function _unWrapWeth(_receiver, _amount) {
                                  let freePtr := mload(0x40)
                                  let transferPtr := add(freePtr, 4)
                                  mstore(freePtr, _SELECTORS2) // withdraw amountWith to amount
                                  // transfer
                                  mstore(add(transferPtr, 4), _WNATIVE_RELAY)
                                  mstore(add(transferPtr, 36), _amount)
                                  let success := call(gas(), _WETH, 0, transferPtr, 68, 0, 0)
                                  if iszero(success) {
                                      _revertWithReason(
                                          0x000000147472616e736665722077657468206661696c65640000000000000000,
                                          88
                                      ) // transfer weth failed
                                  }
                                  // withdraw
                                  mstore(add(freePtr, 4), _amount)
                                  success := call(gas(), _WNATIVE_RELAY, 0, freePtr, 36, 0, 0)
                                  if iszero(success) {
                                      _revertWithReason(
                                          0x0000001477697468647261772077657468206661696c65640000000000000000,
                                          88
                                      ) // withdraw weth failed
                                  }
                                  // msg.value transfer
                                  success := call(gas(), _receiver, _amount, 0, 0, 0, 0)
                                  if iszero(success) {
                                      _revertWithReason(
                                          0x0000001173656e64206574686572206661696c65640000000000000000000000,
                                          85
                                      ) // send ether failed
                                  }
                              }
                              function _token0(_pool) -> token0 {
                                  let freePtr := mload(0x40)
                                  mstore(freePtr, _SELECTORS)
                                  let success := staticcall(gas(), _pool, freePtr, 0x4, 0, 0)
                                  if iszero(success) {
                                      _revertWithReason(
                                          0x0000001167657420746f6b656e30206661696c65640000000000000000000000,
                                          85
                                      ) // get token0 failed
                                  }
                                  returndatacopy(0, 0, 32)
                                  token0 := mload(0)
                              }
                              function _token1(_pool) -> token1 {
                                  let freePtr := mload(0x40)
                                  mstore(freePtr, _SELECTORS)
                                  let success := staticcall(
                                      gas(),
                                      _pool,
                                      add(freePtr, 4),
                                      0x4,
                                      0,
                                      0
                                  )
                                  if iszero(success) {
                                      _revertWithReason(
                                          0x0000001167657420746f6b656e31206661696c65640000000000000000000000,
                                          84
                                      ) // get token1 failed
                                  }
                                  returndatacopy(0, 0, 32)
                                  token1 := mload(0)
                              }
                              function _emitEvent(
                                  _firstPoolStart,
                                  _lastPoolStart,
                                  _returnAmount,
                                  wrapWeth,
                                  unwrapWeth
                              ) -> srcToken {
                                  srcToken := _ETH
                                  let toToken := _ETH
                                  if eq(wrapWeth, false) {
                                      let firstPool := calldataload(_firstPoolStart)
                                      switch eq(0, and(firstPool, _ONE_FOR_ZERO_MASK))
                                      case true {
                                          srcToken := _token0(firstPool)
                                      }
                                      default {
                                          srcToken := _token1(firstPool)
                                      }
                                  }
                                  if eq(unwrapWeth, false) {
                                      let lastPool := calldataload(_lastPoolStart)
                                      switch eq(0, and(lastPool, _ONE_FOR_ZERO_MASK))
                                      case true {
                                          toToken := _token1(lastPool)
                                      }
                                      default {
                                          toToken := _token0(lastPool)
                                      }
                                  }
                                  let freePtr := mload(0x40)
                                  mstore(0, srcToken)
                                  mstore(32, toToken)
                                  mstore(64, origin())
                                  // mstore(96, _initAmount) //avoid stack too deep, since i mstore the initAmount to 96, so no need to re-mstore it
                                  mstore(128, _returnAmount)
                                  log1(
                                      0,
                                      160,
                                      0x1bb43f2da90e35f7b0cf38521ca95a49e68eb42fac49924930a5bd73cdf7576c
                                  )
                                  mstore(0x40, freePtr)
                              }
                              let firstPoolStart
                              let lastPoolStart
                              {
                                  let len := pools.length
                                  firstPoolStart := pools.offset //
                                  lastPoolStart := sub(add(firstPoolStart, mul(len, 32)), 32)
                                  if eq(len, 0) {
                                      mstore(
                                          0,
                                          0x67e7c0f600000000000000000000000000000000000000000000000000000000
                                      ) // EmptyPools()
                                      revert(0, 4)
                                  }
                              }
                              let wrapWeth := gt(callvalue(), 0)
                              if wrapWeth {
                                  _wrapWeth(amount)
                                  payer := address()
                              }
                              mstore(96, amount) // 96 is not override by _makeSwap, since it only use freePtr memory, and it is not override by unWrapWeth ethier
                              for {
                                  let i := firstPoolStart
                              } lt(i, lastPoolStart) {
                                  i := add(i, 32)
                              } {
                                  amount := _makeSwap(address(), payer, calldataload(i), amount)
                                  payer := address()
                              }
                              let unwrapWeth := gt(
                                  and(calldataload(lastPoolStart), _WETH_UNWRAP_MASK),
                                  0
                              ) // pools[lastIndex] & _WETH_UNWRAP_MASK > 0
                              // last one or only one
                              switch unwrapWeth
                              case 1 {
                                  returnAmount := _makeSwap(
                                      address(),
                                      payer,
                                      calldataload(lastPoolStart),
                                      amount
                                  )
                                  _unWrapWeth(receiver, returnAmount)
                              }
                              case 0 {
                                  returnAmount := _makeSwap(
                                      receiver,
                                      payer,
                                      calldataload(lastPoolStart),
                                      amount
                                  )
                              }
                              if lt(returnAmount, minReturn) {
                                  _revertWithReason(
                                      0x000000164d696e2072657475726e206e6f742072656163686564000000000000,
                                      90
                                  ) // Min return not reached
                              }
                              srcTokenAddr := _emitEvent(
                                  firstPoolStart,
                                  lastPoolStart,
                                  returnAmount,
                                  wrapWeth,
                                  unwrapWeth
                              )
                          }
                      }
                      /// @inheritdoc IUniswapV3SwapCallback
                      function uniswapV3SwapCallback(
                          int256 amount0Delta,
                          int256 amount1Delta,
                          bytes calldata /*data*/
                      ) external override {
                          assembly {
                              // solhint-disable-line no-inline-assembly
                              function reRevert() {
                                  returndatacopy(0, 0, returndatasize())
                                  revert(0, returndatasize())
                              }
                              function validateERC20Transfer(status) {
                                  if iszero(status) {
                                      reRevert()
                                  }
                                  let success := or(
                                      iszero(returndatasize()), // empty return data
                                      and(gt(returndatasize(), 31), eq(mload(0), 1)) // true in return data
                                  )
                                  if iszero(success) {
                                      mstore(
                                          0,
                                          0xf27f64e400000000000000000000000000000000000000000000000000000000
                                      ) // ERC20TransferFailed()
                                      revert(0, 4)
                                  }
                              }
                              let emptyPtr := mload(0x40)
                              let resultPtr := add(emptyPtr, 21) // 0x15 = _FF_FACTORY size
                              mstore(emptyPtr, _SELECTORS)
                              // token0
                              if iszero(staticcall(gas(), caller(), emptyPtr, 4, 0, 32)) {
                                  reRevert()
                              }
                              //token1
                              if iszero(
                                  staticcall(gas(), caller(), add(emptyPtr, 4), 4, 32, 32)
                              ) {
                                  reRevert()
                              }
                              // fee
                              if iszero(
                                  staticcall(gas(), caller(), add(emptyPtr, 8), 4, 64, 32)
                              ) {
                                  reRevert()
                              }
                              let token
                              let amount
                              switch sgt(amount0Delta, 0)
                              case 1 {
                                  token := mload(0)
                                  amount := amount0Delta
                              }
                              default {
                                  token := mload(32)
                                  amount := amount1Delta
                              }
                              // let salt := keccak256(0, 96)
                              mstore(emptyPtr, _FF_FACTORY)
                              mstore(resultPtr, keccak256(0, 96)) // Compute the inner hash in-place
                              mstore(add(resultPtr, 32), _POOL_INIT_CODE_HASH)
                              let pool := and(keccak256(emptyPtr, 85), _ADDRESS_MASK)
                              if iszero(eq(pool, caller())) {
                                  // if xor(pool, caller()) {
                                  mstore(
                                      0,
                                      0xb2c0272200000000000000000000000000000000000000000000000000000000
                                  ) // BadPool()
                                  revert(0, 4)
                              }
                              let payer := calldataload(132) // 4+32+32+32+32 = 132
                              mstore(emptyPtr, _SELECTORS)
                              switch eq(payer, address())
                              case 1 {
                                  // token.safeTransfer(msg.sender,amount)
                                  mstore(add(emptyPtr, 0x10), caller())
                                  mstore(add(emptyPtr, 0x30), amount)
                                  validateERC20Transfer(
                                      call(gas(), token, 0, add(emptyPtr, 0x0c), 0x44, 0, 0x20)
                                  )
                              }
                              default {
                                  // approveProxy.claimTokens(token, payer, msg.sender, amount);
                                  mstore(add(emptyPtr, 0x14), token)
                                  mstore(add(emptyPtr, 0x34), payer)
                                  mstore(add(emptyPtr, 0x54), caller())
                                  mstore(add(emptyPtr, 0x74), amount)
                                  validateERC20Transfer(
                                      call(
                                          gas(),
                                          _APPROVE_PROXY,
                                          0,
                                          add(emptyPtr, 0x10),
                                          0x84,
                                          0,
                                          0x20
                                      )
                                  )
                              }
                          }
                      }
                  }
                  

                  File 3 of 9: 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
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                  File 4 of 9: UniswapV2Pair
                  // File: contracts/interfaces/IUniswapV2Pair.sol
                  
                  pragma solidity >=0.5.0;
                  
                  interface IUniswapV2Pair {
                      event Approval(address indexed owner, address indexed spender, uint value);
                      event Transfer(address indexed from, address indexed to, uint value);
                  
                      function name() external pure returns (string memory);
                      function symbol() external pure returns (string memory);
                      function decimals() external pure returns (uint8);
                      function totalSupply() external view returns (uint);
                      function balanceOf(address owner) external view returns (uint);
                      function allowance(address owner, address spender) external view returns (uint);
                  
                      function approve(address spender, uint value) external returns (bool);
                      function transfer(address to, uint value) external returns (bool);
                      function transferFrom(address from, address to, uint value) external returns (bool);
                  
                      function DOMAIN_SEPARATOR() external view returns (bytes32);
                      function PERMIT_TYPEHASH() external pure returns (bytes32);
                      function nonces(address owner) external view returns (uint);
                  
                      function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
                  
                      event Mint(address indexed sender, uint amount0, uint amount1);
                      event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
                      event Swap(
                          address indexed sender,
                          uint amount0In,
                          uint amount1In,
                          uint amount0Out,
                          uint amount1Out,
                          address indexed to
                      );
                      event Sync(uint112 reserve0, uint112 reserve1);
                  
                      function MINIMUM_LIQUIDITY() external pure returns (uint);
                      function factory() external view returns (address);
                      function token0() external view returns (address);
                      function token1() external view returns (address);
                      function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
                      function price0CumulativeLast() external view returns (uint);
                      function price1CumulativeLast() external view returns (uint);
                      function kLast() external view returns (uint);
                  
                      function mint(address to) external returns (uint liquidity);
                      function burn(address to) external returns (uint amount0, uint amount1);
                      function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
                      function skim(address to) external;
                      function sync() external;
                  
                      function initialize(address, address) external;
                  }
                  
                  // File: contracts/interfaces/IUniswapV2ERC20.sol
                  
                  pragma solidity >=0.5.0;
                  
                  interface IUniswapV2ERC20 {
                      event Approval(address indexed owner, address indexed spender, uint value);
                      event Transfer(address indexed from, address indexed to, uint value);
                  
                      function name() external pure returns (string memory);
                      function symbol() external pure returns (string memory);
                      function decimals() external pure returns (uint8);
                      function totalSupply() external view returns (uint);
                      function balanceOf(address owner) external view returns (uint);
                      function allowance(address owner, address spender) external view returns (uint);
                  
                      function approve(address spender, uint value) external returns (bool);
                      function transfer(address to, uint value) external returns (bool);
                      function transferFrom(address from, address to, uint value) external returns (bool);
                  
                      function DOMAIN_SEPARATOR() external view returns (bytes32);
                      function PERMIT_TYPEHASH() external pure returns (bytes32);
                      function nonces(address owner) external view returns (uint);
                  
                      function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
                  }
                  
                  // File: contracts/libraries/SafeMath.sol
                  
                  pragma solidity =0.5.16;
                  
                  // a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)
                  
                  library SafeMath {
                      function add(uint x, uint y) internal pure returns (uint z) {
                          require((z = x + y) >= x, 'ds-math-add-overflow');
                      }
                  
                      function sub(uint x, uint y) internal pure returns (uint z) {
                          require((z = x - y) <= x, 'ds-math-sub-underflow');
                      }
                  
                      function mul(uint x, uint y) internal pure returns (uint z) {
                          require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
                      }
                  }
                  
                  // File: contracts/UniswapV2ERC20.sol
                  
                  pragma solidity =0.5.16;
                  
                  
                  
                  contract UniswapV2ERC20 is IUniswapV2ERC20 {
                      using SafeMath for uint;
                  
                      string public constant name = 'Uniswap V2';
                      string public constant symbol = 'UNI-V2';
                      uint8 public constant decimals = 18;
                      uint  public totalSupply;
                      mapping(address => uint) public balanceOf;
                      mapping(address => mapping(address => uint)) public allowance;
                  
                      bytes32 public DOMAIN_SEPARATOR;
                      // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
                      bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
                      mapping(address => uint) public nonces;
                  
                      event Approval(address indexed owner, address indexed spender, uint value);
                      event Transfer(address indexed from, address indexed to, uint value);
                  
                      constructor() public {
                          uint chainId;
                          assembly {
                              chainId := chainid
                          }
                          DOMAIN_SEPARATOR = keccak256(
                              abi.encode(
                                  keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
                                  keccak256(bytes(name)),
                                  keccak256(bytes('1')),
                                  chainId,
                                  address(this)
                              )
                          );
                      }
                  
                      function _mint(address to, uint value) internal {
                          totalSupply = totalSupply.add(value);
                          balanceOf[to] = balanceOf[to].add(value);
                          emit Transfer(address(0), to, value);
                      }
                  
                      function _burn(address from, uint value) internal {
                          balanceOf[from] = balanceOf[from].sub(value);
                          totalSupply = totalSupply.sub(value);
                          emit Transfer(from, address(0), value);
                      }
                  
                      function _approve(address owner, address spender, uint value) private {
                          allowance[owner][spender] = value;
                          emit Approval(owner, spender, value);
                      }
                  
                      function _transfer(address from, address to, uint value) private {
                          balanceOf[from] = balanceOf[from].sub(value);
                          balanceOf[to] = balanceOf[to].add(value);
                          emit Transfer(from, to, value);
                      }
                  
                      function approve(address spender, uint value) external returns (bool) {
                          _approve(msg.sender, spender, value);
                          return true;
                      }
                  
                      function transfer(address to, uint value) external returns (bool) {
                          _transfer(msg.sender, to, value);
                          return true;
                      }
                  
                      function transferFrom(address from, address to, uint value) external returns (bool) {
                          if (allowance[from][msg.sender] != uint(-1)) {
                              allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
                          }
                          _transfer(from, to, value);
                          return true;
                      }
                  
                      function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
                          require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
                          bytes32 digest = keccak256(
                              abi.encodePacked(
                                  '\x19\x01',
                                  DOMAIN_SEPARATOR,
                                  keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
                              )
                          );
                          address recoveredAddress = ecrecover(digest, v, r, s);
                          require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');
                          _approve(owner, spender, value);
                      }
                  }
                  
                  // File: contracts/libraries/Math.sol
                  
                  pragma solidity =0.5.16;
                  
                  // a library for performing various math operations
                  
                  library Math {
                      function min(uint x, uint y) internal pure returns (uint z) {
                          z = x < y ? x : y;
                      }
                  
                      // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
                      function sqrt(uint y) internal pure returns (uint z) {
                          if (y > 3) {
                              z = y;
                              uint x = y / 2 + 1;
                              while (x < z) {
                                  z = x;
                                  x = (y / x + x) / 2;
                              }
                          } else if (y != 0) {
                              z = 1;
                          }
                      }
                  }
                  
                  // File: contracts/libraries/UQ112x112.sol
                  
                  pragma solidity =0.5.16;
                  
                  // a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))
                  
                  // range: [0, 2**112 - 1]
                  // resolution: 1 / 2**112
                  
                  library UQ112x112 {
                      uint224 constant Q112 = 2**112;
                  
                      // encode a uint112 as a UQ112x112
                      function encode(uint112 y) internal pure returns (uint224 z) {
                          z = uint224(y) * Q112; // never overflows
                      }
                  
                      // divide a UQ112x112 by a uint112, returning a UQ112x112
                      function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
                          z = x / uint224(y);
                      }
                  }
                  
                  // File: contracts/interfaces/IERC20.sol
                  
                  pragma solidity >=0.5.0;
                  
                  interface IERC20 {
                      event Approval(address indexed owner, address indexed spender, uint value);
                      event Transfer(address indexed from, address indexed to, uint value);
                  
                      function name() external view returns (string memory);
                      function symbol() external view returns (string memory);
                      function decimals() external view returns (uint8);
                      function totalSupply() external view returns (uint);
                      function balanceOf(address owner) external view returns (uint);
                      function allowance(address owner, address spender) external view returns (uint);
                  
                      function approve(address spender, uint value) external returns (bool);
                      function transfer(address to, uint value) external returns (bool);
                      function transferFrom(address from, address to, uint value) external returns (bool);
                  }
                  
                  // File: contracts/interfaces/IUniswapV2Factory.sol
                  
                  pragma solidity >=0.5.0;
                  
                  interface IUniswapV2Factory {
                      event PairCreated(address indexed token0, address indexed token1, address pair, uint);
                  
                      function feeTo() external view returns (address);
                      function feeToSetter() external view returns (address);
                  
                      function getPair(address tokenA, address tokenB) external view returns (address pair);
                      function allPairs(uint) external view returns (address pair);
                      function allPairsLength() external view returns (uint);
                  
                      function createPair(address tokenA, address tokenB) external returns (address pair);
                  
                      function setFeeTo(address) external;
                      function setFeeToSetter(address) external;
                  }
                  
                  // File: contracts/interfaces/IUniswapV2Callee.sol
                  
                  pragma solidity >=0.5.0;
                  
                  interface IUniswapV2Callee {
                      function uniswapV2Call(address sender, uint amount0, uint amount1, bytes calldata data) external;
                  }
                  
                  // File: contracts/UniswapV2Pair.sol
                  
                  pragma solidity =0.5.16;
                  
                  
                  
                  
                  
                  
                  
                  
                  contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
                      using SafeMath  for uint;
                      using UQ112x112 for uint224;
                  
                      uint public constant MINIMUM_LIQUIDITY = 10**3;
                      bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));
                  
                      address public factory;
                      address public token0;
                      address public token1;
                  
                      uint112 private reserve0;           // uses single storage slot, accessible via getReserves
                      uint112 private reserve1;           // uses single storage slot, accessible via getReserves
                      uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves
                  
                      uint public price0CumulativeLast;
                      uint public price1CumulativeLast;
                      uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event
                  
                      uint private unlocked = 1;
                      modifier lock() {
                          require(unlocked == 1, 'UniswapV2: LOCKED');
                          unlocked = 0;
                          _;
                          unlocked = 1;
                      }
                  
                      function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
                          _reserve0 = reserve0;
                          _reserve1 = reserve1;
                          _blockTimestampLast = blockTimestampLast;
                      }
                  
                      function _safeTransfer(address token, address to, uint value) private {
                          (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
                          require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');
                      }
                  
                      event Mint(address indexed sender, uint amount0, uint amount1);
                      event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
                      event Swap(
                          address indexed sender,
                          uint amount0In,
                          uint amount1In,
                          uint amount0Out,
                          uint amount1Out,
                          address indexed to
                      );
                      event Sync(uint112 reserve0, uint112 reserve1);
                  
                      constructor() public {
                          factory = msg.sender;
                      }
                  
                      // called once by the factory at time of deployment
                      function initialize(address _token0, address _token1) external {
                          require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // sufficient check
                          token0 = _token0;
                          token1 = _token1;
                      }
                  
                      // update reserves and, on the first call per block, price accumulators
                      function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
                          require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
                          uint32 blockTimestamp = uint32(block.timestamp % 2**32);
                          uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
                          if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
                              // * never overflows, and + overflow is desired
                              price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
                              price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
                          }
                          reserve0 = uint112(balance0);
                          reserve1 = uint112(balance1);
                          blockTimestampLast = blockTimestamp;
                          emit Sync(reserve0, reserve1);
                      }
                  
                      // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
                      function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
                          address feeTo = IUniswapV2Factory(factory).feeTo();
                          feeOn = feeTo != address(0);
                          uint _kLast = kLast; // gas savings
                          if (feeOn) {
                              if (_kLast != 0) {
                                  uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                                  uint rootKLast = Math.sqrt(_kLast);
                                  if (rootK > rootKLast) {
                                      uint numerator = totalSupply.mul(rootK.sub(rootKLast));
                                      uint denominator = rootK.mul(5).add(rootKLast);
                                      uint liquidity = numerator / denominator;
                                      if (liquidity > 0) _mint(feeTo, liquidity);
                                  }
                              }
                          } else if (_kLast != 0) {
                              kLast = 0;
                          }
                      }
                  
                      // this low-level function should be called from a contract which performs important safety checks
                      function mint(address to) external lock returns (uint liquidity) {
                          (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
                          uint balance0 = IERC20(token0).balanceOf(address(this));
                          uint balance1 = IERC20(token1).balanceOf(address(this));
                          uint amount0 = balance0.sub(_reserve0);
                          uint amount1 = balance1.sub(_reserve1);
                  
                          bool feeOn = _mintFee(_reserve0, _reserve1);
                          uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
                          if (_totalSupply == 0) {
                              liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
                             _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
                          } else {
                              liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
                          }
                          require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');
                          _mint(to, liquidity);
                  
                          _update(balance0, balance1, _reserve0, _reserve1);
                          if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
                          emit Mint(msg.sender, amount0, amount1);
                      }
                  
                      // this low-level function should be called from a contract which performs important safety checks
                      function burn(address to) external lock returns (uint amount0, uint amount1) {
                          (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
                          address _token0 = token0;                                // gas savings
                          address _token1 = token1;                                // gas savings
                          uint balance0 = IERC20(_token0).balanceOf(address(this));
                          uint balance1 = IERC20(_token1).balanceOf(address(this));
                          uint liquidity = balanceOf[address(this)];
                  
                          bool feeOn = _mintFee(_reserve0, _reserve1);
                          uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
                          amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
                          amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
                          require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
                          _burn(address(this), liquidity);
                          _safeTransfer(_token0, to, amount0);
                          _safeTransfer(_token1, to, amount1);
                          balance0 = IERC20(_token0).balanceOf(address(this));
                          balance1 = IERC20(_token1).balanceOf(address(this));
                  
                          _update(balance0, balance1, _reserve0, _reserve1);
                          if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
                          emit Burn(msg.sender, amount0, amount1, to);
                      }
                  
                      // this low-level function should be called from a contract which performs important safety checks
                      function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
                          require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');
                          (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
                          require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');
                  
                          uint balance0;
                          uint balance1;
                          { // scope for _token{0,1}, avoids stack too deep errors
                          address _token0 = token0;
                          address _token1 = token1;
                          require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');
                          if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
                          if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
                          if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
                          balance0 = IERC20(_token0).balanceOf(address(this));
                          balance1 = IERC20(_token1).balanceOf(address(this));
                          }
                          uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
                          uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
                          require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');
                          { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
                          uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
                          uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
                          require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
                          }
                  
                          _update(balance0, balance1, _reserve0, _reserve1);
                          emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
                      }
                  
                      // force balances to match reserves
                      function skim(address to) external lock {
                          address _token0 = token0; // gas savings
                          address _token1 = token1; // gas savings
                          _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
                          _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
                      }
                  
                      // force reserves to match balances
                      function sync() external lock {
                          _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
                      }
                  }

                  File 5 of 9: VraToken
                  // 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;
                      }
                  }
                  
                  /**
                   * @dev Interface of the ERC777Token standard as defined in the EIP.
                   *
                   * This contract uses the
                   * https://eips.ethereum.org/EIPS/eip-1820[ERC1820 registry standard] to let
                   * token holders and recipients react to token movements by using setting implementers
                   * for the associated interfaces in said registry. See {IERC1820Registry} and
                   * {ERC1820Implementer}.
                   */
                  interface IERC777 {
                      /**
                       * @dev Returns the name of the token.
                       */
                      function name() external view returns (string memory);
                  
                      /**
                       * @dev Returns the symbol of the token, usually a shorter version of the
                       * name.
                       */
                      function symbol() external view returns (string memory);
                  
                      /**
                       * @dev Returns the smallest part of the token that is not divisible. This
                       * means all token operations (creation, movement and destruction) must have
                       * amounts that are a multiple of this number.
                       *
                       * For most token contracts, this value will equal 1.
                       */
                      function granularity() external view returns (uint256);
                  
                      /**
                       * @dev Returns the amount of tokens in existence.
                       */
                      function totalSupply() external view returns (uint256);
                  
                      /**
                       * @dev Returns the amount of tokens owned by an account (`owner`).
                       */
                      function balanceOf(address owner) external view returns (uint256);
                  
                      /**
                       * @dev Moves `amount` tokens from the caller's account to `recipient`.
                       *
                       * If send or receive hooks are registered for the caller and `recipient`,
                       * the corresponding functions will be called with `data` and empty
                       * `operatorData`. See {IERC777Sender} and {IERC777Recipient}.
                       *
                       * Emits a {Sent} event.
                       *
                       * Requirements
                       *
                       * - the caller must have at least `amount` tokens.
                       * - `recipient` cannot be the zero address.
                       * - if `recipient` is a contract, it must implement the {IERC777Recipient}
                       * interface.
                       */
                      function send(address recipient, uint256 amount, bytes calldata data) external;
                  
                      /**
                       * @dev Destroys `amount` tokens from the caller's account, reducing the
                       * total supply.
                       *
                       * If a send hook is registered for the caller, the corresponding function
                       * will be called with `data` and empty `operatorData`. See {IERC777Sender}.
                       *
                       * Emits a {Burned} event.
                       *
                       * Requirements
                       *
                       * - the caller must have at least `amount` tokens.
                       */
                      function burn(uint256 amount, bytes calldata data) external;
                  
                      /**
                       * @dev Returns true if an account is an operator of `tokenHolder`.
                       * Operators can send and burn tokens on behalf of their owners. All
                       * accounts are their own operator.
                       *
                       * See {operatorSend} and {operatorBurn}.
                       */
                      function isOperatorFor(address operator, address tokenHolder) external view returns (bool);
                  
                      /**
                       * @dev Make an account an operator of the caller.
                       *
                       * See {isOperatorFor}.
                       *
                       * Emits an {AuthorizedOperator} event.
                       *
                       * Requirements
                       *
                       * - `operator` cannot be calling address.
                       */
                      function authorizeOperator(address operator) external;
                  
                      /**
                       * @dev Revoke an account's operator status for the caller.
                       *
                       * See {isOperatorFor} and {defaultOperators}.
                       *
                       * Emits a {RevokedOperator} event.
                       *
                       * Requirements
                       *
                       * - `operator` cannot be calling address.
                       */
                      function revokeOperator(address operator) external;
                  
                      /**
                       * @dev Returns the list of default operators. These accounts are operators
                       * for all token holders, even if {authorizeOperator} was never called on
                       * them.
                       *
                       * This list is immutable, but individual holders may revoke these via
                       * {revokeOperator}, in which case {isOperatorFor} will return false.
                       */
                      function defaultOperators() external view returns (address[] memory);
                  
                      /**
                       * @dev Moves `amount` tokens from `sender` to `recipient`. The caller must
                       * be an operator of `sender`.
                       *
                       * If send or receive hooks are registered for `sender` and `recipient`,
                       * the corresponding functions will be called with `data` and
                       * `operatorData`. See {IERC777Sender} and {IERC777Recipient}.
                       *
                       * Emits a {Sent} event.
                       *
                       * Requirements
                       *
                       * - `sender` cannot be the zero address.
                       * - `sender` must have at least `amount` tokens.
                       * - the caller must be an operator for `sender`.
                       * - `recipient` cannot be the zero address.
                       * - if `recipient` is a contract, it must implement the {IERC777Recipient}
                       * interface.
                       */
                      function operatorSend(
                          address sender,
                          address recipient,
                          uint256 amount,
                          bytes calldata data,
                          bytes calldata operatorData
                      ) external;
                  
                      /**
                       * @dev Destroys `amount` tokens from `account`, reducing the total supply.
                       * The caller must be an operator of `account`.
                       *
                       * If a send hook is registered for `account`, the corresponding function
                       * will be called with `data` and `operatorData`. See {IERC777Sender}.
                       *
                       * Emits a {Burned} event.
                       *
                       * Requirements
                       *
                       * - `account` cannot be the zero address.
                       * - `account` must have at least `amount` tokens.
                       * - the caller must be an operator for `account`.
                       */
                      function operatorBurn(
                          address account,
                          uint256 amount,
                          bytes calldata data,
                          bytes calldata operatorData
                      ) external;
                  
                      event Sent(
                          address indexed operator,
                          address indexed from,
                          address indexed to,
                          uint256 amount,
                          bytes data,
                          bytes operatorData
                      );
                  
                      event Minted(address indexed operator, address indexed to, uint256 amount, bytes data, bytes operatorData);
                  
                      event Burned(address indexed operator, address indexed from, uint256 amount, bytes data, bytes operatorData);
                  
                      event AuthorizedOperator(address indexed operator, address indexed tokenHolder);
                  
                      event RevokedOperator(address indexed operator, address indexed tokenHolder);
                  }
                  
                  /**
                   * @dev Interface of the ERC777TokensRecipient standard as defined in the EIP.
                   *
                   * Accounts can be notified of {IERC777} tokens being sent to them by having a
                   * contract implement this interface (contract holders can be their own
                   * implementer) and registering it on the
                   * https://eips.ethereum.org/EIPS/eip-1820[ERC1820 global registry].
                   *
                   * See {IERC1820Registry} and {ERC1820Implementer}.
                   */
                  interface IERC777Recipient {
                      /**
                       * @dev Called by an {IERC777} token contract whenever tokens are being
                       * moved or created into a registered account (`to`). The type of operation
                       * is conveyed by `from` being the zero address or not.
                       *
                       * This call occurs _after_ the token contract's state is updated, so
                       * {IERC777-balanceOf}, etc., can be used to query the post-operation state.
                       *
                       * This function may revert to prevent the operation from being executed.
                       */
                      function tokensReceived(
                          address operator,
                          address from,
                          address to,
                          uint256 amount,
                          bytes calldata userData,
                          bytes calldata operatorData
                      ) external;
                  }
                  
                  /**
                   * @dev Interface of the ERC777TokensSender standard as defined in the EIP.
                   *
                   * {IERC777} Token holders can be notified of operations performed on their
                   * tokens by having a contract implement this interface (contract holders can be
                   *  their own implementer) and registering it on the
                   * https://eips.ethereum.org/EIPS/eip-1820[ERC1820 global registry].
                   *
                   * See {IERC1820Registry} and {ERC1820Implementer}.
                   */
                  interface IERC777Sender {
                      /**
                       * @dev Called by an {IERC777} token contract whenever a registered holder's
                       * (`from`) tokens are about to be moved or destroyed. The type of operation
                       * is conveyed by `to` being the zero address or not.
                       *
                       * This call occurs _before_ the token contract's state is updated, so
                       * {IERC777-balanceOf}, etc., can be used to query the pre-operation state.
                       *
                       * This function may revert to prevent the operation from being executed.
                       */
                      function tokensToSend(
                          address operator,
                          address from,
                          address to,
                          uint256 amount,
                          bytes calldata userData,
                          bytes calldata operatorData
                      ) external;
                  }
                  
                  /**
                   * @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);
                  }
                  
                  /**
                   * @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, 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) {
                          return sub(a, b, "SafeMath: subtraction overflow");
                      }
                  
                      /**
                       * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
                       * overflow (when the result is negative).
                       *
                       * 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);
                          uint256 c = a - b;
                  
                          return c;
                      }
                  
                      /**
                       * @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) {
                          // 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 0;
                          }
                  
                          uint256 c = a * b;
                          require(c / a == b, "SafeMath: multiplication overflow");
                  
                          return c;
                      }
                  
                      /**
                       * @dev Returns the integer division of two unsigned integers. Reverts 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) {
                          return div(a, b, "SafeMath: division by zero");
                      }
                  
                      /**
                       * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
                          require(b > 0, errorMessage);
                          uint256 c = a / b;
                          // assert(a == b * c + a % b); // There is no case in which this doesn't hold
                  
                          return c;
                      }
                  
                      /**
                       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                       * Reverts 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) {
                          return mod(a, b, "SafeMath: modulo by zero");
                      }
                  
                      /**
                       * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
                       * Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) {
                          require(b != 0, errorMessage);
                          return a % b;
                      }
                  }
                  
                  /**
                   * @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);
                              }
                          }
                      }
                  }
                  
                  /**
                   * @dev Interface of the global ERC1820 Registry, as defined in the
                   * https://eips.ethereum.org/EIPS/eip-1820[EIP]. Accounts may register
                   * implementers for interfaces in this registry, as well as query support.
                   *
                   * Implementers may be shared by multiple accounts, and can also implement more
                   * than a single interface for each account. Contracts can implement interfaces
                   * for themselves, but externally-owned accounts (EOA) must delegate this to a
                   * contract.
                   *
                   * {IERC165} interfaces can also be queried via the registry.
                   *
                   * For an in-depth explanation and source code analysis, see the EIP text.
                   */
                  interface IERC1820Registry {
                      /**
                       * @dev Sets `newManager` as the manager for `account`. A manager of an
                       * account is able to set interface implementers for it.
                       *
                       * By default, each account is its own manager. Passing a value of `0x0` in
                       * `newManager` will reset the manager to this initial state.
                       *
                       * Emits a {ManagerChanged} event.
                       *
                       * Requirements:
                       *
                       * - the caller must be the current manager for `account`.
                       */
                      function setManager(address account, address newManager) external;
                  
                      /**
                       * @dev Returns the manager for `account`.
                       *
                       * See {setManager}.
                       */
                      function getManager(address account) external view returns (address);
                  
                      /**
                       * @dev Sets the `implementer` contract as ``account``'s implementer for
                       * `interfaceHash`.
                       *
                       * `account` being the zero address is an alias for the caller's address.
                       * The zero address can also be used in `implementer` to remove an old one.
                       *
                       * See {interfaceHash} to learn how these are created.
                       *
                       * Emits an {InterfaceImplementerSet} event.
                       *
                       * Requirements:
                       *
                       * - the caller must be the current manager for `account`.
                       * - `interfaceHash` must not be an {IERC165} interface id (i.e. it must not
                       * end in 28 zeroes).
                       * - `implementer` must implement {IERC1820Implementer} and return true when
                       * queried for support, unless `implementer` is the caller. See
                       * {IERC1820Implementer-canImplementInterfaceForAddress}.
                       */
                      function setInterfaceImplementer(address account, bytes32 _interfaceHash, address implementer) external;
                  
                      /**
                       * @dev Returns the implementer of `interfaceHash` for `account`. If no such
                       * implementer is registered, returns the zero address.
                       *
                       * If `interfaceHash` is an {IERC165} interface id (i.e. it ends with 28
                       * zeroes), `account` will be queried for support of it.
                       *
                       * `account` being the zero address is an alias for the caller's address.
                       */
                      function getInterfaceImplementer(address account, bytes32 _interfaceHash) external view returns (address);
                  
                      /**
                       * @dev Returns the interface hash for an `interfaceName`, as defined in the
                       * corresponding
                       * https://eips.ethereum.org/EIPS/eip-1820#interface-name[section of the EIP].
                       */
                      function interfaceHash(string calldata interfaceName) external pure returns (bytes32);
                  
                      /**
                       *  @notice Updates the cache with whether the contract implements an ERC165 interface or not.
                       *  @param account Address of the contract for which to update the cache.
                       *  @param interfaceId ERC165 interface for which to update the cache.
                       */
                      function updateERC165Cache(address account, bytes4 interfaceId) external;
                  
                      /**
                       *  @notice Checks whether a contract implements an ERC165 interface or not.
                       *  If the result is not cached a direct lookup on the contract address is performed.
                       *  If the result is not cached or the cached value is out-of-date, the cache MUST be updated manually by calling
                       *  {updateERC165Cache} with the contract address.
                       *  @param account Address of the contract to check.
                       *  @param interfaceId ERC165 interface to check.
                       *  @return True if `account` implements `interfaceId`, false otherwise.
                       */
                      function implementsERC165Interface(address account, bytes4 interfaceId) external view returns (bool);
                  
                      /**
                       *  @notice Checks whether a contract implements an ERC165 interface or not without using nor updating the cache.
                       *  @param account Address of the contract to check.
                       *  @param interfaceId ERC165 interface to check.
                       *  @return True if `account` implements `interfaceId`, false otherwise.
                       */
                      function implementsERC165InterfaceNoCache(address account, bytes4 interfaceId) external view returns (bool);
                  
                      event InterfaceImplementerSet(address indexed account, bytes32 indexed interfaceHash, address indexed implementer);
                  
                      event ManagerChanged(address indexed account, address indexed newManager);
                  }
                  
                  /**
                   * @dev Implementation of the {IERC777} 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}.
                   *
                   * Support for ERC20 is included in this contract, as specified by the EIP: both
                   * the ERC777 and ERC20 interfaces can be safely used when interacting with it.
                   * Both {IERC777-Sent} and {IERC20-Transfer} events are emitted on token
                   * movements.
                   *
                   * Additionally, the {IERC777-granularity} value is hard-coded to `1`, meaning that there
                   * are no special restrictions in the amount of tokens that created, moved, or
                   * destroyed. This makes integration with ERC20 applications seamless.
                   */
                  contract ERC777 is Context, IERC777, IERC20 {
                      using SafeMath for uint256;
                      using Address for address;
                  
                      IERC1820Registry constant internal _ERC1820_REGISTRY = IERC1820Registry(0x1820a4B7618BdE71Dce8cdc73aAB6C95905faD24);
                  
                      mapping(address => uint256) private _balances;
                  
                      uint256 private _totalSupply;
                  
                      string private _name;
                      string private _symbol;
                  
                      // We inline the result of the following hashes because Solidity doesn't resolve them at compile time.
                      // See https://github.com/ethereum/solidity/issues/4024.
                  
                      // keccak256("ERC777TokensSender")
                      bytes32 constant private _TOKENS_SENDER_INTERFACE_HASH =
                          0x29ddb589b1fb5fc7cf394961c1adf5f8c6454761adf795e67fe149f658abe895;
                  
                      // keccak256("ERC777TokensRecipient")
                      bytes32 constant private _TOKENS_RECIPIENT_INTERFACE_HASH =
                          0xb281fc8c12954d22544db45de3159a39272895b169a852b314f9cc762e44c53b;
                  
                      // This isn't ever read from - it's only used to respond to the defaultOperators query.
                      address[] private _defaultOperatorsArray;
                  
                      // Immutable, but accounts may revoke them (tracked in __revokedDefaultOperators).
                      mapping(address => bool) private _defaultOperators;
                  
                      // For each account, a mapping of its operators and revoked default operators.
                      mapping(address => mapping(address => bool)) private _operators;
                      mapping(address => mapping(address => bool)) private _revokedDefaultOperators;
                  
                      // ERC20-allowances
                      mapping (address => mapping (address => uint256)) private _allowances;
                  
                      /**
                       * @dev `defaultOperators` may be an empty array.
                       */
                      constructor(
                          string memory name_,
                          string memory symbol_,
                          address[] memory defaultOperators_
                      ) public {
                          _name = name_;
                          _symbol = symbol_;
                  
                          _defaultOperatorsArray = defaultOperators_;
                          for (uint256 i = 0; i < _defaultOperatorsArray.length; i++) {
                              _defaultOperators[_defaultOperatorsArray[i]] = true;
                          }
                  
                          // register interfaces
                          _ERC1820_REGISTRY.setInterfaceImplementer(address(this), keccak256("ERC777Token"), address(this));
                          _ERC1820_REGISTRY.setInterfaceImplementer(address(this), keccak256("ERC20Token"), address(this));
                      }
                  
                      /**
                       * @dev See {IERC777-name}.
                       */
                      function name() public view override returns (string memory) {
                          return _name;
                      }
                  
                      /**
                       * @dev See {IERC777-symbol}.
                       */
                      function symbol() public view override returns (string memory) {
                          return _symbol;
                      }
                  
                      /**
                       * @dev See {ERC20-decimals}.
                       *
                       * Always returns 18, as per the
                       * [ERC777 EIP](https://eips.ethereum.org/EIPS/eip-777#backward-compatibility).
                       */
                      function decimals() public pure returns (uint8) {
                          return 18;
                      }
                  
                      /**
                       * @dev See {IERC777-granularity}.
                       *
                       * This implementation always returns `1`.
                       */
                      function granularity() public view override returns (uint256) {
                          return 1;
                      }
                  
                      /**
                       * @dev See {IERC777-totalSupply}.
                       */
                      function totalSupply() public view override(IERC20, IERC777) returns (uint256) {
                          return _totalSupply;
                      }
                  
                      /**
                       * @dev Returns the amount of tokens owned by an account (`tokenHolder`).
                       */
                      function balanceOf(address tokenHolder) public view override(IERC20, IERC777) returns (uint256) {
                          return _balances[tokenHolder];
                      }
                  
                      /**
                       * @dev See {IERC777-send}.
                       *
                       * Also emits a {IERC20-Transfer} event for ERC20 compatibility.
                       */
                      function send(address recipient, uint256 amount, bytes memory data) public override  {
                          _send(_msgSender(), recipient, amount, data, "", true);
                      }
                  
                      /**
                       * @dev See {IERC20-transfer}.
                       *
                       * Unlike `send`, `recipient` is _not_ required to implement the {IERC777Recipient}
                       * interface if it is a contract.
                       *
                       * Also emits a {Sent} event.
                       */
                      function transfer(address recipient, uint256 amount) public override returns (bool) {
                          require(recipient != address(0), "ERC777: transfer to the zero address");
                  
                          address from = _msgSender();
                  
                          _callTokensToSend(from, from, recipient, amount, "", "");
                  
                          _move(from, from, recipient, amount, "", "");
                  
                          _callTokensReceived(from, from, recipient, amount, "", "", false);
                  
                          return true;
                      }
                  
                      /**
                       * @dev See {IERC777-burn}.
                       *
                       * Also emits a {IERC20-Transfer} event for ERC20 compatibility.
                       */
                      function burn(uint256 amount, bytes memory data) public override  {
                          _burn(_msgSender(), amount, data, "");
                      }
                  
                      /**
                       * @dev See {IERC777-isOperatorFor}.
                       */
                      function isOperatorFor(
                          address operator,
                          address tokenHolder
                      ) public view override returns (bool) {
                          return operator == tokenHolder ||
                              (_defaultOperators[operator] && !_revokedDefaultOperators[tokenHolder][operator]) ||
                              _operators[tokenHolder][operator];
                      }
                  
                      /**
                       * @dev See {IERC777-authorizeOperator}.
                       */
                      function authorizeOperator(address operator) public override  {
                          require(_msgSender() != operator, "ERC777: authorizing self as operator");
                  
                          if (_defaultOperators[operator]) {
                              delete _revokedDefaultOperators[_msgSender()][operator];
                          } else {
                              _operators[_msgSender()][operator] = true;
                          }
                  
                          emit AuthorizedOperator(operator, _msgSender());
                      }
                  
                      /**
                       * @dev See {IERC777-revokeOperator}.
                       */
                      function revokeOperator(address operator) public override  {
                          require(operator != _msgSender(), "ERC777: revoking self as operator");
                  
                          if (_defaultOperators[operator]) {
                              _revokedDefaultOperators[_msgSender()][operator] = true;
                          } else {
                              delete _operators[_msgSender()][operator];
                          }
                  
                          emit RevokedOperator(operator, _msgSender());
                      }
                  
                      /**
                       * @dev See {IERC777-defaultOperators}.
                       */
                      function defaultOperators() public view override returns (address[] memory) {
                          return _defaultOperatorsArray;
                      }
                  
                      /**
                       * @dev See {IERC777-operatorSend}.
                       *
                       * Emits {Sent} and {IERC20-Transfer} events.
                       */
                      function operatorSend(
                          address sender,
                          address recipient,
                          uint256 amount,
                          bytes memory data,
                          bytes memory operatorData
                      )
                      public override
                      {
                          require(isOperatorFor(_msgSender(), sender), "ERC777: caller is not an operator for holder");
                          _send(sender, recipient, amount, data, operatorData, true);
                      }
                  
                      /**
                       * @dev See {IERC777-operatorBurn}.
                       *
                       * Emits {Burned} and {IERC20-Transfer} events.
                       */
                      function operatorBurn(address account, uint256 amount, bytes memory data, bytes memory operatorData) public override {
                          require(isOperatorFor(_msgSender(), account), "ERC777: caller is not an operator for holder");
                          _burn(account, amount, data, operatorData);
                      }
                  
                      /**
                       * @dev See {IERC20-allowance}.
                       *
                       * Note that operator and allowance concepts are orthogonal: operators may
                       * not have allowance, and accounts with allowance may not be operators
                       * themselves.
                       */
                      function allowance(address holder, address spender) public view override returns (uint256) {
                          return _allowances[holder][spender];
                      }
                  
                      /**
                       * @dev See {IERC20-approve}.
                       *
                       * Note that accounts cannot have allowance issued by their operators.
                       */
                      function approve(address spender, uint256 value) public override returns (bool) {
                          address holder = _msgSender();
                          _approve(holder, spender, value);
                          return true;
                      }
                  
                     /**
                      * @dev See {IERC20-transferFrom}.
                      *
                      * Note that operator and allowance concepts are orthogonal: operators cannot
                      * call `transferFrom` (unless they have allowance), and accounts with
                      * allowance cannot call `operatorSend` (unless they are operators).
                      *
                      * Emits {Sent}, {IERC20-Transfer} and {IERC20-Approval} events.
                      */
                      function transferFrom(address holder, address recipient, uint256 amount) public override returns (bool) {
                          require(recipient != address(0), "ERC777: transfer to the zero address");
                          require(holder != address(0), "ERC777: transfer from the zero address");
                  
                          address spender = _msgSender();
                  
                          _callTokensToSend(spender, holder, recipient, amount, "", "");
                  
                          _move(spender, holder, recipient, amount, "", "");
                          _approve(holder, spender, _allowances[holder][spender].sub(amount, "ERC777: transfer amount exceeds allowance"));
                  
                          _callTokensReceived(spender, holder, recipient, amount, "", "", false);
                  
                          return true;
                      }
                  
                      /**
                       * @dev Creates `amount` tokens and assigns them to `account`, increasing
                       * the total supply.
                       *
                       * If a send hook is registered for `account`, the corresponding function
                       * will be called with `operator`, `data` and `operatorData`.
                       *
                       * See {IERC777Sender} and {IERC777Recipient}.
                       *
                       * Emits {Minted} and {IERC20-Transfer} events.
                       *
                       * Requirements
                       *
                       * - `account` cannot be the zero address.
                       * - if `account` is a contract, it must implement the {IERC777Recipient}
                       * interface.
                       */
                      function _mint(
                          address account,
                          uint256 amount,
                          bytes memory userData,
                          bytes memory operatorData
                      )
                      internal virtual
                      {
                          require(account != address(0), "ERC777: mint to the zero address");
                  
                          address operator = _msgSender();
                  
                          _beforeTokenTransfer(operator, address(0), account, amount);
                  
                          // Update state variables
                          _totalSupply = _totalSupply.add(amount);
                          _balances[account] = _balances[account].add(amount);
                  
                          _callTokensReceived(operator, address(0), account, amount, userData, operatorData, true);
                  
                          emit Minted(operator, account, amount, userData, operatorData);
                          emit Transfer(address(0), account, amount);
                      }
                  
                      /**
                       * @dev Send tokens
                       * @param from address token holder address
                       * @param to address recipient address
                       * @param amount uint256 amount of tokens to transfer
                       * @param userData bytes extra information provided by the token holder (if any)
                       * @param operatorData bytes extra information provided by the operator (if any)
                       * @param requireReceptionAck if true, contract recipients are required to implement ERC777TokensRecipient
                       */
                      function _send(
                          address from,
                          address to,
                          uint256 amount,
                          bytes memory userData,
                          bytes memory operatorData,
                          bool requireReceptionAck
                      )
                          internal
                      {
                          require(from != address(0), "ERC777: send from the zero address");
                          require(to != address(0), "ERC777: send to the zero address");
                  
                          address operator = _msgSender();
                  
                          _callTokensToSend(operator, from, to, amount, userData, operatorData);
                  
                          _move(operator, from, to, amount, userData, operatorData);
                  
                          _callTokensReceived(operator, from, to, amount, userData, operatorData, requireReceptionAck);
                      }
                  
                      /**
                       * @dev Burn tokens
                       * @param from address token holder address
                       * @param amount uint256 amount of tokens to burn
                       * @param data bytes extra information provided by the token holder
                       * @param operatorData bytes extra information provided by the operator (if any)
                       */
                      function _burn(
                          address from,
                          uint256 amount,
                          bytes memory data,
                          bytes memory operatorData
                      )
                          internal virtual
                      {
                          require(from != address(0), "ERC777: burn from the zero address");
                  
                          address operator = _msgSender();
                  
                          _beforeTokenTransfer(operator, from, address(0), amount);
                  
                          _callTokensToSend(operator, from, address(0), amount, data, operatorData);
                  
                          // Update state variables
                          _balances[from] = _balances[from].sub(amount, "ERC777: burn amount exceeds balance");
                          _totalSupply = _totalSupply.sub(amount);
                  
                          emit Burned(operator, from, amount, data, operatorData);
                          emit Transfer(from, address(0), amount);
                      }
                  
                      function _move(
                          address operator,
                          address from,
                          address to,
                          uint256 amount,
                          bytes memory userData,
                          bytes memory operatorData
                      )
                          private
                      {
                          _beforeTokenTransfer(operator, from, to, amount);
                  
                          _balances[from] = _balances[from].sub(amount, "ERC777: transfer amount exceeds balance");
                          _balances[to] = _balances[to].add(amount);
                  
                          emit Sent(operator, from, to, amount, userData, operatorData);
                          emit Transfer(from, to, amount);
                      }
                  
                      /**
                       * @dev See {ERC20-_approve}.
                       *
                       * Note that accounts cannot have allowance issued by their operators.
                       */
                      function _approve(address holder, address spender, uint256 value) internal {
                          require(holder != address(0), "ERC777: approve from the zero address");
                          require(spender != address(0), "ERC777: approve to the zero address");
                  
                          _allowances[holder][spender] = value;
                          emit Approval(holder, spender, value);
                      }
                  
                      /**
                       * @dev Call from.tokensToSend() if the interface is registered
                       * @param operator address operator requesting the transfer
                       * @param from address token holder address
                       * @param to address recipient address
                       * @param amount uint256 amount of tokens to transfer
                       * @param userData bytes extra information provided by the token holder (if any)
                       * @param operatorData bytes extra information provided by the operator (if any)
                       */
                      function _callTokensToSend(
                          address operator,
                          address from,
                          address to,
                          uint256 amount,
                          bytes memory userData,
                          bytes memory operatorData
                      )
                          private
                      {
                          address implementer = _ERC1820_REGISTRY.getInterfaceImplementer(from, _TOKENS_SENDER_INTERFACE_HASH);
                          if (implementer != address(0)) {
                              IERC777Sender(implementer).tokensToSend(operator, from, to, amount, userData, operatorData);
                          }
                      }
                  
                      /**
                       * @dev Call to.tokensReceived() if the interface is registered. Reverts if the recipient is a contract but
                       * tokensReceived() was not registered for the recipient
                       * @param operator address operator requesting the transfer
                       * @param from address token holder address
                       * @param to address recipient address
                       * @param amount uint256 amount of tokens to transfer
                       * @param userData bytes extra information provided by the token holder (if any)
                       * @param operatorData bytes extra information provided by the operator (if any)
                       * @param requireReceptionAck if true, contract recipients are required to implement ERC777TokensRecipient
                       */
                      function _callTokensReceived(
                          address operator,
                          address from,
                          address to,
                          uint256 amount,
                          bytes memory userData,
                          bytes memory operatorData,
                          bool requireReceptionAck
                      )
                          private
                      {
                          address implementer = _ERC1820_REGISTRY.getInterfaceImplementer(to, _TOKENS_RECIPIENT_INTERFACE_HASH);
                          if (implementer != address(0)) {
                              IERC777Recipient(implementer).tokensReceived(operator, from, to, amount, userData, operatorData);
                          } else if (requireReceptionAck) {
                              require(!to.isContract(), "ERC777: token recipient contract has no implementer for ERC777TokensRecipient");
                          }
                      }
                  
                      /**
                       * @dev Hook that is called before any token transfer. This includes
                       * calls to {send}, {transfer}, {operatorSend}, 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 operator, address from, address to, uint256 amount) internal virtual { }
                  }
                  
                  /**
                   * @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 Pausable is Context {
                      /**
                       * @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.
                       */
                      constructor () internal {
                          _paused = false;
                      }
                  
                      /**
                       * @dev Returns true if the contract is paused, and false otherwise.
                       */
                      function paused() public view 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());
                      }
                  }
                  
                  /**
                   * @dev Library for managing
                   * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
                   * types.
                   *
                   * Sets have the following properties:
                   *
                   * - Elements are added, removed, and checked for existence in constant time
                   * (O(1)).
                   * - Elements are enumerated in O(n). No guarantees are made on the ordering.
                   *
                   * ```
                   * contract Example {
                   *     // Add the library methods
                   *     using EnumerableSet for EnumerableSet.AddressSet;
                   *
                   *     // Declare a set state variable
                   *     EnumerableSet.AddressSet private mySet;
                   * }
                   * ```
                   *
                   * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
                   * and `uint256` (`UintSet`) are supported.
                   */
                  library EnumerableSet {
                      // To implement this library for multiple types with as little code
                      // repetition as possible, we write it in terms of a generic Set type with
                      // bytes32 values.
                      // The Set implementation uses private functions, and user-facing
                      // implementations (such as AddressSet) are just wrappers around the
                      // underlying Set.
                      // This means that we can only create new EnumerableSets for types that fit
                      // in bytes32.
                  
                      struct Set {
                          // Storage of set values
                          bytes32[] _values;
                  
                          // Position of the value in the `values` array, plus 1 because index 0
                          // means a value is not in the set.
                          mapping (bytes32 => uint256) _indexes;
                      }
                  
                      /**
                       * @dev Add a value to a set. O(1).
                       *
                       * Returns true if the value was added to the set, that is if it was not
                       * already present.
                       */
                      function _add(Set storage set, bytes32 value) private returns (bool) {
                          if (!_contains(set, value)) {
                              set._values.push(value);
                              // The value is stored at length-1, but we add 1 to all indexes
                              // and use 0 as a sentinel value
                              set._indexes[value] = set._values.length;
                              return true;
                          } else {
                              return false;
                          }
                      }
                  
                      /**
                       * @dev Removes a value from a set. O(1).
                       *
                       * Returns true if the value was removed from the set, that is if it was
                       * present.
                       */
                      function _remove(Set storage set, bytes32 value) private returns (bool) {
                          // We read and store the value's index to prevent multiple reads from the same storage slot
                          uint256 valueIndex = set._indexes[value];
                  
                          if (valueIndex != 0) { // Equivalent to contains(set, value)
                              // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
                              // the array, and then remove the last element (sometimes called as 'swap and pop').
                              // This modifies the order of the array, as noted in {at}.
                  
                              uint256 toDeleteIndex = valueIndex - 1;
                              uint256 lastIndex = set._values.length - 1;
                  
                              // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
                              // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.
                  
                              bytes32 lastvalue = set._values[lastIndex];
                  
                              // Move the last value to the index where the value to delete is
                              set._values[toDeleteIndex] = lastvalue;
                              // Update the index for the moved value
                              set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based
                  
                              // Delete the slot where the moved value was stored
                              set._values.pop();
                  
                              // Delete the index for the deleted slot
                              delete set._indexes[value];
                  
                              return true;
                          } else {
                              return false;
                          }
                      }
                  
                      /**
                       * @dev Returns true if the value is in the set. O(1).
                       */
                      function _contains(Set storage set, bytes32 value) private view returns (bool) {
                          return set._indexes[value] != 0;
                      }
                  
                      /**
                       * @dev Returns the number of values on the set. O(1).
                       */
                      function _length(Set storage set) private view returns (uint256) {
                          return set._values.length;
                      }
                  
                     /**
                      * @dev Returns the value stored at position `index` in the set. O(1).
                      *
                      * Note that there are no guarantees on the ordering of values inside the
                      * array, and it may change when more values are added or removed.
                      *
                      * Requirements:
                      *
                      * - `index` must be strictly less than {length}.
                      */
                      function _at(Set storage set, uint256 index) private view returns (bytes32) {
                          require(set._values.length > index, "EnumerableSet: index out of bounds");
                          return set._values[index];
                      }
                  
                      // Bytes32Set
                  
                      struct Bytes32Set {
                          Set _inner;
                      }
                  
                      /**
                       * @dev Add a value to a set. O(1).
                       *
                       * Returns true if the value was added to the set, that is if it was not
                       * already present.
                       */
                      function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
                          return _add(set._inner, value);
                      }
                  
                      /**
                       * @dev Removes a value from a set. O(1).
                       *
                       * Returns true if the value was removed from the set, that is if it was
                       * present.
                       */
                      function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
                          return _remove(set._inner, value);
                      }
                  
                      /**
                       * @dev Returns true if the value is in the set. O(1).
                       */
                      function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
                          return _contains(set._inner, value);
                      }
                  
                      /**
                       * @dev Returns the number of values in the set. O(1).
                       */
                      function length(Bytes32Set storage set) internal view returns (uint256) {
                          return _length(set._inner);
                      }
                  
                     /**
                      * @dev Returns the value stored at position `index` in the set. O(1).
                      *
                      * Note that there are no guarantees on the ordering of values inside the
                      * array, and it may change when more values are added or removed.
                      *
                      * Requirements:
                      *
                      * - `index` must be strictly less than {length}.
                      */
                      function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
                          return _at(set._inner, index);
                      }
                  
                      // AddressSet
                  
                      struct AddressSet {
                          Set _inner;
                      }
                  
                      /**
                       * @dev Add a value to a set. O(1).
                       *
                       * Returns true if the value was added to the set, that is if it was not
                       * already present.
                       */
                      function add(AddressSet storage set, address value) internal returns (bool) {
                          return _add(set._inner, bytes32(uint256(value)));
                      }
                  
                      /**
                       * @dev Removes a value from a set. O(1).
                       *
                       * Returns true if the value was removed from the set, that is if it was
                       * present.
                       */
                      function remove(AddressSet storage set, address value) internal returns (bool) {
                          return _remove(set._inner, bytes32(uint256(value)));
                      }
                  
                      /**
                       * @dev Returns true if the value is in the set. O(1).
                       */
                      function contains(AddressSet storage set, address value) internal view returns (bool) {
                          return _contains(set._inner, bytes32(uint256(value)));
                      }
                  
                      /**
                       * @dev Returns the number of values in the set. O(1).
                       */
                      function length(AddressSet storage set) internal view returns (uint256) {
                          return _length(set._inner);
                      }
                  
                     /**
                      * @dev Returns the value stored at position `index` in the set. O(1).
                      *
                      * Note that there are no guarantees on the ordering of values inside the
                      * array, and it may change when more values are added or removed.
                      *
                      * Requirements:
                      *
                      * - `index` must be strictly less than {length}.
                      */
                      function at(AddressSet storage set, uint256 index) internal view returns (address) {
                          return address(uint256(_at(set._inner, index)));
                      }
                  
                  
                      // UintSet
                  
                      struct UintSet {
                          Set _inner;
                      }
                  
                      /**
                       * @dev Add a value to a set. O(1).
                       *
                       * Returns true if the value was added to the set, that is if it was not
                       * already present.
                       */
                      function add(UintSet storage set, uint256 value) internal returns (bool) {
                          return _add(set._inner, bytes32(value));
                      }
                  
                      /**
                       * @dev Removes a value from a set. O(1).
                       *
                       * Returns true if the value was removed from the set, that is if it was
                       * present.
                       */
                      function remove(UintSet storage set, uint256 value) internal returns (bool) {
                          return _remove(set._inner, bytes32(value));
                      }
                  
                      /**
                       * @dev Returns true if the value is in the set. O(1).
                       */
                      function contains(UintSet storage set, uint256 value) internal view returns (bool) {
                          return _contains(set._inner, bytes32(value));
                      }
                  
                      /**
                       * @dev Returns the number of values on the set. O(1).
                       */
                      function length(UintSet storage set) internal view returns (uint256) {
                          return _length(set._inner);
                      }
                  
                     /**
                      * @dev Returns the value stored at position `index` in the set. O(1).
                      *
                      * Note that there are no guarantees on the ordering of values inside the
                      * array, and it may change when more values are added or removed.
                      *
                      * Requirements:
                      *
                      * - `index` must be strictly less than {length}.
                      */
                      function at(UintSet storage set, uint256 index) internal view returns (uint256) {
                          return uint256(_at(set._inner, index));
                      }
                  }
                  
                  /**
                   * @dev Contract module that allows children to implement role-based access
                   * control mechanisms.
                   *
                   * Roles are referred to by their `bytes32` identifier. These should be exposed
                   * in the external API and be unique. The best way to achieve this is by
                   * using `public constant` hash digests:
                   *
                   * ```
                   * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
                   * ```
                   *
                   * Roles can be used to represent a set of permissions. To restrict access to a
                   * function call, use {hasRole}:
                   *
                   * ```
                   * function foo() public {
                   *     require(hasRole(MY_ROLE, msg.sender));
                   *     ...
                   * }
                   * ```
                   *
                   * Roles can be granted and revoked dynamically via the {grantRole} and
                   * {revokeRole} functions. Each role has an associated admin role, and only
                   * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
                   *
                   * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
                   * that only accounts with this role will be able to grant or revoke other
                   * roles. More complex role relationships can be created by using
                   * {_setRoleAdmin}.
                   *
                   * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
                   * grant and revoke this role. Extra precautions should be taken to secure
                   * accounts that have been granted it.
                   */
                  abstract contract AccessControl is Context {
                      using EnumerableSet for EnumerableSet.AddressSet;
                      using Address for address;
                  
                      struct RoleData {
                          EnumerableSet.AddressSet members;
                          bytes32 adminRole;
                      }
                  
                      mapping (bytes32 => RoleData) private _roles;
                  
                      bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;
                  
                      /**
                       * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
                       *
                       * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
                       * {RoleAdminChanged} not being emitted signaling this.
                       *
                       * _Available since v3.1._
                       */
                      event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);
                  
                      /**
                       * @dev Emitted when `account` is granted `role`.
                       *
                       * `sender` is the account that originated the contract call, an admin role
                       * bearer except when using {_setupRole}.
                       */
                      event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);
                  
                      /**
                       * @dev Emitted when `account` is revoked `role`.
                       *
                       * `sender` is the account that originated the contract call:
                       *   - if using `revokeRole`, it is the admin role bearer
                       *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
                       */
                      event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);
                  
                      /**
                       * @dev Returns `true` if `account` has been granted `role`.
                       */
                      function hasRole(bytes32 role, address account) public view returns (bool) {
                          return _roles[role].members.contains(account);
                      }
                  
                      /**
                       * @dev Returns the number of accounts that have `role`. Can be used
                       * together with {getRoleMember} to enumerate all bearers of a role.
                       */
                      function getRoleMemberCount(bytes32 role) public view returns (uint256) {
                          return _roles[role].members.length();
                      }
                  
                      /**
                       * @dev Returns one of the accounts that have `role`. `index` must be a
                       * value between 0 and {getRoleMemberCount}, non-inclusive.
                       *
                       * Role bearers are not sorted in any particular way, and their ordering may
                       * change at any point.
                       *
                       * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
                       * you perform all queries on the same block. See the following
                       * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
                       * for more information.
                       */
                      function getRoleMember(bytes32 role, uint256 index) public view returns (address) {
                          return _roles[role].members.at(index);
                      }
                  
                      /**
                       * @dev Returns the admin role that controls `role`. See {grantRole} and
                       * {revokeRole}.
                       *
                       * To change a role's admin, use {_setRoleAdmin}.
                       */
                      function getRoleAdmin(bytes32 role) public view returns (bytes32) {
                          return _roles[role].adminRole;
                      }
                  
                      /**
                       * @dev Grants `role` to `account`.
                       *
                       * If `account` had not been already granted `role`, emits a {RoleGranted}
                       * event.
                       *
                       * Requirements:
                       *
                       * - the caller must have ``role``'s admin role.
                       */
                      function grantRole(bytes32 role, address account) public virtual {
                          require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to grant");
                  
                          _grantRole(role, account);
                      }
                  
                      /**
                       * @dev Revokes `role` from `account`.
                       *
                       * If `account` had been granted `role`, emits a {RoleRevoked} event.
                       *
                       * Requirements:
                       *
                       * - the caller must have ``role``'s admin role.
                       */
                      function revokeRole(bytes32 role, address account) public virtual {
                          require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to revoke");
                  
                          _revokeRole(role, account);
                      }
                  
                      /**
                       * @dev Revokes `role` from the calling account.
                       *
                       * Roles are often managed via {grantRole} and {revokeRole}: this function's
                       * purpose is to provide a mechanism for accounts to lose their privileges
                       * if they are compromised (such as when a trusted device is misplaced).
                       *
                       * If the calling account had been granted `role`, emits a {RoleRevoked}
                       * event.
                       *
                       * Requirements:
                       *
                       * - the caller must be `account`.
                       */
                      function renounceRole(bytes32 role, address account) public virtual {
                          require(account == _msgSender(), "AccessControl: can only renounce roles for self");
                  
                          _revokeRole(role, account);
                      }
                  
                      /**
                       * @dev Grants `role` to `account`.
                       *
                       * If `account` had not been already granted `role`, emits a {RoleGranted}
                       * event. Note that unlike {grantRole}, this function doesn't perform any
                       * checks on the calling account.
                       *
                       * [WARNING]
                       * ====
                       * This function should only be called from the constructor when setting
                       * up the initial roles for the system.
                       *
                       * Using this function in any other way is effectively circumventing the admin
                       * system imposed by {AccessControl}.
                       * ====
                       */
                      function _setupRole(bytes32 role, address account) internal virtual {
                          _grantRole(role, account);
                      }
                  
                      /**
                       * @dev Sets `adminRole` as ``role``'s admin role.
                       *
                       * Emits a {RoleAdminChanged} event.
                       */
                      function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
                          emit RoleAdminChanged(role, _roles[role].adminRole, adminRole);
                          _roles[role].adminRole = adminRole;
                      }
                  
                      function _grantRole(bytes32 role, address account) private {
                          if (_roles[role].members.add(account)) {
                              emit RoleGranted(role, account, _msgSender());
                          }
                      }
                  
                      function _revokeRole(bytes32 role, address account) private {
                          if (_roles[role].members.remove(account)) {
                              emit RoleRevoked(role, account, _msgSender());
                          }
                      }
                  }
                  
                  /**
                   * @dev ERC777 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.
                   *
                   * _Available since v3.1._
                   */
                  abstract contract ERC777MintablePausableBlocklistable is Context, AccessControl, ERC777, Pausable {
                      bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
                      bytes32 public constant PAUSER_ROLE = keccak256("PAUSER_ROLE");
                      bytes32 public constant BLOCK_ROLE = keccak256("BLOCK_ROLE");
                  
                      bool public _mintingFinished = false;
                  
                      mapping(address => bool) _blocklist;
                      
                      event Blocked(address account);
                      event Unblocked(address account);
                      event MintFinished();
                  
                      /**
                       * @dev Grants `DEFAULT_ADMIN_ROLE`, `MINTER_ROLE`, and `PAUSER_ROLE` to the account that
                       * deploys the contract.
                       */
                      constructor(        
                          string memory name,
                          string memory symbol,
                          address[] memory defaultOperators
                      ) 
                          public ERC777(name, symbol, defaultOperators) 
                      {
                          _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
                  
                          _setupRole(MINTER_ROLE, _msgSender());
                          _setupRole(PAUSER_ROLE, _msgSender());
                          _setupRole(BLOCK_ROLE, _msgSender());
                      }
                  
                      /**
                       * @dev Pauses all token transfers.
                       *
                       * See {Pausable-_pause}.
                       *
                       * Requirements:
                       *
                       * - the caller must have the `PAUSER_ROLE`.
                       */
                      function pause() public virtual {
                          require(hasRole(PAUSER_ROLE, _msgSender()), "ERC777MintablePausableBlacklistable: must have pauser role to pause");
                          _pause();
                      }
                  
                      /**
                       * @dev Unpauses all token transfers.
                       *
                       * See {Pausable-_unpause}.
                       *
                       * Requirements:
                       *
                       * - the caller must have the `PAUSER_ROLE`.
                       */
                      function unpause() public virtual {
                          require(hasRole(PAUSER_ROLE, _msgSender()), "ERC777MintablePausableBlocklistable: must have pauser role to unpause");
                          _unpause();
                      }
                  
                      /**
                       * @dev Block account
                       *
                       * Requirements:
                       *
                       * - the caller must have the `BLOCK_ROLE`.
                       */
                      function blockAccount(address account) public virtual {
                          require(hasRole(BLOCK_ROLE, _msgSender()), "ERC777MintablePausableBlocklistable: must have block role to block");
                          _blocklist[account] = true;
                          emit Blocked(account);
                      }
                      
                      /**
                       * @dev Unblock account
                       *
                       * Requirements:
                       *
                       * - the caller must have the `BLOCK_ROLE`.
                       */    
                      function unblockAccount(address account) public virtual {
                          require(hasRole(BLOCK_ROLE, _msgSender()), "ERC777MintablePausableBlocklistable: must have block role to unblock");
                          _blocklist[account] = false;
                          emit Unblocked(account);
                      }
                  
                     /**
                      * @return true if the user is blocked
                      */
                      function isBlockListed(address account) public view returns (bool) {
                          return _blocklist[account];
                      }
                  
                      /**
                       * @dev See {ERC777-_mint}.
                       *
                       * Requirements:
                       *
                       * - the caller must have the {MinterRole}.
                       */
                      function mint(
                          address account,
                          uint256 amount,
                          bytes memory userData,
                          bytes memory operatorData
                      ) public virtual {
                          require(hasRole(MINTER_ROLE, _msgSender()), "ERC777MintablePausableBlocklistable: must have minter role to mint");
                          require(!_mintingFinished, "ERC777MintablePausableBlocklistable: mint finished");
                          
                          _mint(account, amount, userData, operatorData);
                      }
                  
                     /**
                      * @return true if the minting is finished
                      */
                      function isFinishedMinting() public view returns (bool) {
                          return _mintingFinished;
                      }
                  
                      /**
                      * @dev Function to stop minting new tokens.
                      * @return True if the operation was successful.
                      */
                      function finishMinting() public returns (bool) {
                          require(hasRole(MINTER_ROLE, _msgSender()), "ERC777MintablePausableBlocklistable: must have minter role to finish minting");
                          _mintingFinished = true;
                  
                          emit MintFinished();
                          return true;
                      }
                  
                      /**
                       * @dev See {ERC777-_beforeTokenTransfer}.
                       *
                       * Requirements:
                       *
                       * - the contract must not be paused.
                       */
                      function _beforeTokenTransfer(
                          address operator, 
                          address from, 
                          address to, 
                          uint256 amount
                      )
                  
                          internal virtual override
                      {
                          super._beforeTokenTransfer(operator, from, to, amount);
                  
                          require(!paused(), "ERC20MintablePausableBlocklistable: token transfer while paused");
                          require(!isBlockListed(operator), "ERC20MintablePausableBlocklistable: account is blocked");
                          require(!isBlockListed(from), "ERC20MintablePausableBlocklistable: account is blocked");
                          require(!isBlockListed(to), "ERC20MintablePausableBlocklistable: account is blocked");
                      }
                  
                  }
                  
                  /**
                   * @title VraToken
                   */
                  contract VraToken is ERC777MintablePausableBlocklistable {
                  
                      /**
                       * @dev Constructor that gives msg.sender all of existing tokens.
                       */
                      constructor () public ERC777MintablePausableBlocklistable("VERA", "VRA", new address[](0)) {
                          _mint(msg.sender, 10356466694667075153057994000, "", "");
                      }  
                  }

                  File 6 of 9: Spender
                  {"Constants.84ef19f8.sol":{"content":"// SPDX-License-Identifier: MIT\r\n\r\npragma solidity ^0.6.0;\r\n\r\nlibrary Constants {\r\n    address internal constant ETH = 0x0000000000000000000000000000000000000000;\r\n}\r\n"},"Spender.3372a096.sol":{"content":"// SPDX-License-Identifier: MIT\r\n\r\npragma solidity ^0.6.0;\r\n\r\nimport \"./Constants.84ef19f8.sol\";\r\n\r\ncontract Spender {\r\n    address public immutable metaswap;\r\n\r\n    constructor() public {\r\n        metaswap = msg.sender;\r\n    }\r\n\r\n    /// @dev Receives ether from swaps\r\n    fallback() external payable {}\r\n\r\n    function swap(address adapter, bytes calldata data) external payable {\r\n        require(msg.sender == metaswap, \"FORBIDDEN\");\r\n        require(adapter != address(0), \"ADAPTER_NOT_PROVIDED\");\r\n        _delegate(adapter, data, \"ADAPTER_DELEGATECALL_FAILED\");\r\n    }\r\n\r\n    /**\r\n     * @dev Performs a delegatecall and bubbles up the errors, adapted from\r\n     * https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Address.sol\r\n     * @param target Address of the contract to delegatecall\r\n     * @param data Data passed in the delegatecall\r\n     * @param errorMessage Fallback revert reason\r\n     */\r\n    function _delegate(\r\n        address target,\r\n        bytes memory data,\r\n        string memory errorMessage\r\n    ) private returns (bytes memory) {\r\n        // solhint-disable-next-line avoid-low-level-calls\r\n        (bool success, bytes memory returndata) = target.delegatecall(data);\r\n        if (success) {\r\n            return returndata;\r\n        } else {\r\n            // Look for revert reason and bubble it up if present\r\n            if (returndata.length \u003e 0) {\r\n                // The easiest way to bubble the revert reason is using memory via assembly\r\n\r\n                // solhint-disable-next-line no-inline-assembly\r\n                assembly {\r\n                    let returndata_size := mload(returndata)\r\n                    revert(add(32, returndata), returndata_size)\r\n                }\r\n            } else {\r\n                revert(errorMessage);\r\n            }\r\n        }\r\n    }\r\n}\r\n"}}

                  File 7 of 9: Proxy
                  pragma solidity ^0.5.3;
                  
                  /// @title Proxy - Generic proxy contract allows to execute all transactions applying the code of a master contract.
                  /// @author Stefan George - <[email protected]>
                  /// @author Richard Meissner - <[email protected]>
                  contract Proxy {
                  
                      // masterCopy always needs to be first declared variable, to ensure that it is at the same location in the contracts to which calls are delegated.
                      // To reduce deployment costs this variable is internal and needs to be retrieved via `getStorageAt`
                      address internal masterCopy;
                  
                      /// @dev Constructor function sets address of master copy contract.
                      /// @param _masterCopy Master copy address.
                      constructor(address _masterCopy)
                          public
                      {
                          require(_masterCopy != address(0), "Invalid master copy address provided");
                          masterCopy = _masterCopy;
                      }
                  
                      /// @dev Fallback function forwards all transactions and returns all received return data.
                      function ()
                          external
                          payable
                      {
                          // solium-disable-next-line security/no-inline-assembly
                          assembly {
                              let masterCopy := and(sload(0), 0xffffffffffffffffffffffffffffffffffffffff)
                              // 0xa619486e == keccak("masterCopy()"). The value is right padded to 32-bytes with 0s
                              if eq(calldataload(0), 0xa619486e00000000000000000000000000000000000000000000000000000000) {
                                  mstore(0, masterCopy)
                                  return(0, 0x20)
                              }
                              calldatacopy(0, 0, calldatasize())
                              let success := delegatecall(gas, masterCopy, 0, calldatasize(), 0, 0)
                              returndatacopy(0, 0, returndatasize())
                              if eq(success, 0) { revert(0, returndatasize()) }
                              return(0, returndatasize())
                          }
                      }
                  }

                  File 8 of 9: ERC1820Registry
                  /* ERC1820 Pseudo-introspection Registry Contract
                   * This standard defines a universal registry smart contract where any address (contract or regular account) can
                   * register which interface it supports and which smart contract is responsible for its implementation.
                   *
                   * Written in 2019 by Jordi Baylina and Jacques Dafflon
                   *
                   * To the extent possible under law, the author(s) have dedicated all copyright and related and neighboring rights to
                   * this software to the public domain worldwide. This software is distributed without any warranty.
                   *
                   * You should have received a copy of the CC0 Public Domain Dedication along with this software. If not, see
                   * <http://creativecommons.org/publicdomain/zero/1.0/>.
                   *
                   *    ███████╗██████╗  ██████╗ ██╗ █████╗ ██████╗  ██████╗
                   *    ██╔════╝██╔══██╗██╔════╝███║██╔══██╗╚════██╗██╔═████╗
                   *    █████╗  ██████╔╝██║     ╚██║╚█████╔╝ █████╔╝██║██╔██║
                   *    ██╔══╝  ██╔══██╗██║      ██║██╔══██╗██╔═══╝ ████╔╝██║
                   *    ███████╗██║  ██║╚██████╗ ██║╚█████╔╝███████╗╚██████╔╝
                   *    ╚══════╝╚═╝  ╚═╝ ╚═════╝ ╚═╝ ╚════╝ ╚══════╝ ╚═════╝
                   *
                   *    ██████╗ ███████╗ ██████╗ ██╗███████╗████████╗██████╗ ██╗   ██╗
                   *    ██╔══██╗██╔════╝██╔════╝ ██║██╔════╝╚══██╔══╝██╔══██╗╚██╗ ██╔╝
                   *    ██████╔╝█████╗  ██║  ███╗██║███████╗   ██║   ██████╔╝ ╚████╔╝
                   *    ██╔══██╗██╔══╝  ██║   ██║██║╚════██║   ██║   ██╔══██╗  ╚██╔╝
                   *    ██║  ██║███████╗╚██████╔╝██║███████║   ██║   ██║  ██║   ██║
                   *    ╚═╝  ╚═╝╚══════╝ ╚═════╝ ╚═╝╚══════╝   ╚═╝   ╚═╝  ╚═╝   ╚═╝
                   *
                   */
                  pragma solidity 0.5.3;
                  // IV is value needed to have a vanity address starting with '0x1820'.
                  // IV: 53759
                  
                  /// @dev The interface a contract MUST implement if it is the implementer of
                  /// some (other) interface for any address other than itself.
                  interface ERC1820ImplementerInterface {
                      /// @notice Indicates whether the contract implements the interface 'interfaceHash' for the address 'addr' or not.
                      /// @param interfaceHash keccak256 hash of the name of the interface
                      /// @param addr Address for which the contract will implement the interface
                      /// @return ERC1820_ACCEPT_MAGIC only if the contract implements 'interfaceHash' for the address 'addr'.
                      function canImplementInterfaceForAddress(bytes32 interfaceHash, address addr) external view returns(bytes32);
                  }
                  
                  
                  /// @title ERC1820 Pseudo-introspection Registry Contract
                  /// @author Jordi Baylina and Jacques Dafflon
                  /// @notice This contract is the official implementation of the ERC1820 Registry.
                  /// @notice For more details, see https://eips.ethereum.org/EIPS/eip-1820
                  contract ERC1820Registry {
                      /// @notice ERC165 Invalid ID.
                      bytes4 constant internal INVALID_ID = 0xffffffff;
                      /// @notice Method ID for the ERC165 supportsInterface method (= `bytes4(keccak256('supportsInterface(bytes4)'))`).
                      bytes4 constant internal ERC165ID = 0x01ffc9a7;
                      /// @notice Magic value which is returned if a contract implements an interface on behalf of some other address.
                      bytes32 constant internal ERC1820_ACCEPT_MAGIC = keccak256(abi.encodePacked("ERC1820_ACCEPT_MAGIC"));
                  
                      /// @notice mapping from addresses and interface hashes to their implementers.
                      mapping(address => mapping(bytes32 => address)) internal interfaces;
                      /// @notice mapping from addresses to their manager.
                      mapping(address => address) internal managers;
                      /// @notice flag for each address and erc165 interface to indicate if it is cached.
                      mapping(address => mapping(bytes4 => bool)) internal erc165Cached;
                  
                      /// @notice Indicates a contract is the 'implementer' of 'interfaceHash' for 'addr'.
                      event InterfaceImplementerSet(address indexed addr, bytes32 indexed interfaceHash, address indexed implementer);
                      /// @notice Indicates 'newManager' is the address of the new manager for 'addr'.
                      event ManagerChanged(address indexed addr, address indexed newManager);
                  
                      /// @notice Query if an address implements an interface and through which contract.
                      /// @param _addr Address being queried for the implementer of an interface.
                      /// (If '_addr' is the zero address then 'msg.sender' is assumed.)
                      /// @param _interfaceHash Keccak256 hash of the name of the interface as a string.
                      /// E.g., 'web3.utils.keccak256("ERC777TokensRecipient")' for the 'ERC777TokensRecipient' interface.
                      /// @return The address of the contract which implements the interface '_interfaceHash' for '_addr'
                      /// or '0' if '_addr' did not register an implementer for this interface.
                      function getInterfaceImplementer(address _addr, bytes32 _interfaceHash) external view returns (address) {
                          address addr = _addr == address(0) ? msg.sender : _addr;
                          if (isERC165Interface(_interfaceHash)) {
                              bytes4 erc165InterfaceHash = bytes4(_interfaceHash);
                              return implementsERC165Interface(addr, erc165InterfaceHash) ? addr : address(0);
                          }
                          return interfaces[addr][_interfaceHash];
                      }
                  
                      /// @notice Sets the contract which implements a specific interface for an address.
                      /// Only the manager defined for that address can set it.
                      /// (Each address is the manager for itself until it sets a new manager.)
                      /// @param _addr Address for which to set the interface.
                      /// (If '_addr' is the zero address then 'msg.sender' is assumed.)
                      /// @param _interfaceHash Keccak256 hash of the name of the interface as a string.
                      /// E.g., 'web3.utils.keccak256("ERC777TokensRecipient")' for the 'ERC777TokensRecipient' interface.
                      /// @param _implementer Contract address implementing '_interfaceHash' for '_addr'.
                      function setInterfaceImplementer(address _addr, bytes32 _interfaceHash, address _implementer) external {
                          address addr = _addr == address(0) ? msg.sender : _addr;
                          require(getManager(addr) == msg.sender, "Not the manager");
                  
                          require(!isERC165Interface(_interfaceHash), "Must not be an ERC165 hash");
                          if (_implementer != address(0) && _implementer != msg.sender) {
                              require(
                                  ERC1820ImplementerInterface(_implementer)
                                      .canImplementInterfaceForAddress(_interfaceHash, addr) == ERC1820_ACCEPT_MAGIC,
                                  "Does not implement the interface"
                              );
                          }
                          interfaces[addr][_interfaceHash] = _implementer;
                          emit InterfaceImplementerSet(addr, _interfaceHash, _implementer);
                      }
                  
                      /// @notice Sets '_newManager' as manager for '_addr'.
                      /// The new manager will be able to call 'setInterfaceImplementer' for '_addr'.
                      /// @param _addr Address for which to set the new manager.
                      /// @param _newManager Address of the new manager for 'addr'. (Pass '0x0' to reset the manager to '_addr'.)
                      function setManager(address _addr, address _newManager) external {
                          require(getManager(_addr) == msg.sender, "Not the manager");
                          managers[_addr] = _newManager == _addr ? address(0) : _newManager;
                          emit ManagerChanged(_addr, _newManager);
                      }
                  
                      /// @notice Get the manager of an address.
                      /// @param _addr Address for which to return the manager.
                      /// @return Address of the manager for a given address.
                      function getManager(address _addr) public view returns(address) {
                          // By default the manager of an address is the same address
                          if (managers[_addr] == address(0)) {
                              return _addr;
                          } else {
                              return managers[_addr];
                          }
                      }
                  
                      /// @notice Compute the keccak256 hash of an interface given its name.
                      /// @param _interfaceName Name of the interface.
                      /// @return The keccak256 hash of an interface name.
                      function interfaceHash(string calldata _interfaceName) external pure returns(bytes32) {
                          return keccak256(abi.encodePacked(_interfaceName));
                      }
                  
                      /* --- ERC165 Related Functions --- */
                      /* --- Developed in collaboration with William Entriken. --- */
                  
                      /// @notice Updates the cache with whether the contract implements an ERC165 interface or not.
                      /// @param _contract Address of the contract for which to update the cache.
                      /// @param _interfaceId ERC165 interface for which to update the cache.
                      function updateERC165Cache(address _contract, bytes4 _interfaceId) external {
                          interfaces[_contract][_interfaceId] = implementsERC165InterfaceNoCache(
                              _contract, _interfaceId) ? _contract : address(0);
                          erc165Cached[_contract][_interfaceId] = true;
                      }
                  
                      /// @notice Checks whether a contract implements an ERC165 interface or not.
                      //  If the result is not cached a direct lookup on the contract address is performed.
                      //  If the result is not cached or the cached value is out-of-date, the cache MUST be updated manually by calling
                      //  'updateERC165Cache' with the contract address.
                      /// @param _contract Address of the contract to check.
                      /// @param _interfaceId ERC165 interface to check.
                      /// @return True if '_contract' implements '_interfaceId', false otherwise.
                      function implementsERC165Interface(address _contract, bytes4 _interfaceId) public view returns (bool) {
                          if (!erc165Cached[_contract][_interfaceId]) {
                              return implementsERC165InterfaceNoCache(_contract, _interfaceId);
                          }
                          return interfaces[_contract][_interfaceId] == _contract;
                      }
                  
                      /// @notice Checks whether a contract implements an ERC165 interface or not without using nor updating the cache.
                      /// @param _contract Address of the contract to check.
                      /// @param _interfaceId ERC165 interface to check.
                      /// @return True if '_contract' implements '_interfaceId', false otherwise.
                      function implementsERC165InterfaceNoCache(address _contract, bytes4 _interfaceId) public view returns (bool) {
                          uint256 success;
                          uint256 result;
                  
                          (success, result) = noThrowCall(_contract, ERC165ID);
                          if (success == 0 || result == 0) {
                              return false;
                          }
                  
                          (success, result) = noThrowCall(_contract, INVALID_ID);
                          if (success == 0 || result != 0) {
                              return false;
                          }
                  
                          (success, result) = noThrowCall(_contract, _interfaceId);
                          if (success == 1 && result == 1) {
                              return true;
                          }
                          return false;
                      }
                  
                      /// @notice Checks whether the hash is a ERC165 interface (ending with 28 zeroes) or not.
                      /// @param _interfaceHash The hash to check.
                      /// @return True if '_interfaceHash' is an ERC165 interface (ending with 28 zeroes), false otherwise.
                      function isERC165Interface(bytes32 _interfaceHash) internal pure returns (bool) {
                          return _interfaceHash & 0x00000000FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF == 0;
                      }
                  
                      /// @dev Make a call on a contract without throwing if the function does not exist.
                      function noThrowCall(address _contract, bytes4 _interfaceId)
                          internal view returns (uint256 success, uint256 result)
                      {
                          bytes4 erc165ID = ERC165ID;
                  
                          assembly {
                              let x := mload(0x40)               // Find empty storage location using "free memory pointer"
                              mstore(x, erc165ID)                // Place signature at beginning of empty storage
                              mstore(add(x, 0x04), _interfaceId) // Place first argument directly next to signature
                  
                              success := staticcall(
                                  30000,                         // 30k gas
                                  _contract,                     // To addr
                                  x,                             // Inputs are stored at location x
                                  0x24,                          // Inputs are 36 (4 + 32) bytes long
                                  x,                             // Store output over input (saves space)
                                  0x20                           // Outputs are 32 bytes long
                              )
                  
                              result := mload(x)                 // Load the result
                          }
                      }
                  }

                  File 9 of 9: GnosisSafe
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  import "./base/ModuleManager.sol";
                  import "./base/OwnerManager.sol";
                  import "./base/FallbackManager.sol";
                  import "./base/GuardManager.sol";
                  import "./common/EtherPaymentFallback.sol";
                  import "./common/Singleton.sol";
                  import "./common/SignatureDecoder.sol";
                  import "./common/SecuredTokenTransfer.sol";
                  import "./common/StorageAccessible.sol";
                  import "./interfaces/ISignatureValidator.sol";
                  import "./external/GnosisSafeMath.sol";
                  /// @title Gnosis Safe - A multisignature wallet with support for confirmations using signed messages based on ERC191.
                  /// @author Stefan George - <[email protected]>
                  /// @author Richard Meissner - <[email protected]>
                  contract GnosisSafe is
                      EtherPaymentFallback,
                      Singleton,
                      ModuleManager,
                      OwnerManager,
                      SignatureDecoder,
                      SecuredTokenTransfer,
                      ISignatureValidatorConstants,
                      FallbackManager,
                      StorageAccessible,
                      GuardManager
                  {
                      using GnosisSafeMath for uint256;
                      string public constant VERSION = "1.3.0";
                      // keccak256(
                      //     "EIP712Domain(uint256 chainId,address verifyingContract)"
                      // );
                      bytes32 private constant DOMAIN_SEPARATOR_TYPEHASH = 0x47e79534a245952e8b16893a336b85a3d9ea9fa8c573f3d803afb92a79469218;
                      // keccak256(
                      //     "SafeTx(address to,uint256 value,bytes data,uint8 operation,uint256 safeTxGas,uint256 baseGas,uint256 gasPrice,address gasToken,address refundReceiver,uint256 nonce)"
                      // );
                      bytes32 private constant SAFE_TX_TYPEHASH = 0xbb8310d486368db6bd6f849402fdd73ad53d316b5a4b2644ad6efe0f941286d8;
                      event SafeSetup(address indexed initiator, address[] owners, uint256 threshold, address initializer, address fallbackHandler);
                      event ApproveHash(bytes32 indexed approvedHash, address indexed owner);
                      event SignMsg(bytes32 indexed msgHash);
                      event ExecutionFailure(bytes32 txHash, uint256 payment);
                      event ExecutionSuccess(bytes32 txHash, uint256 payment);
                      uint256 public nonce;
                      bytes32 private _deprecatedDomainSeparator;
                      // Mapping to keep track of all message hashes that have been approve by ALL REQUIRED owners
                      mapping(bytes32 => uint256) public signedMessages;
                      // Mapping to keep track of all hashes (message or transaction) that have been approve by ANY owners
                      mapping(address => mapping(bytes32 => uint256)) public approvedHashes;
                      // This constructor ensures that this contract can only be used as a master copy for Proxy contracts
                      constructor() {
                          // By setting the threshold it is not possible to call setup anymore,
                          // so we create a Safe with 0 owners and threshold 1.
                          // This is an unusable Safe, perfect for the singleton
                          threshold = 1;
                      }
                      /// @dev Setup function sets initial storage of contract.
                      /// @param _owners List of Safe owners.
                      /// @param _threshold Number of required confirmations for a Safe transaction.
                      /// @param to Contract address for optional delegate call.
                      /// @param data Data payload for optional delegate call.
                      /// @param fallbackHandler Handler for fallback calls to this contract
                      /// @param paymentToken Token that should be used for the payment (0 is ETH)
                      /// @param payment Value that should be paid
                      /// @param paymentReceiver Adddress that should receive the payment (or 0 if tx.origin)
                      function setup(
                          address[] calldata _owners,
                          uint256 _threshold,
                          address to,
                          bytes calldata data,
                          address fallbackHandler,
                          address paymentToken,
                          uint256 payment,
                          address payable paymentReceiver
                      ) external {
                          // setupOwners checks if the Threshold is already set, therefore preventing that this method is called twice
                          setupOwners(_owners, _threshold);
                          if (fallbackHandler != address(0)) internalSetFallbackHandler(fallbackHandler);
                          // As setupOwners can only be called if the contract has not been initialized we don't need a check for setupModules
                          setupModules(to, data);
                          if (payment > 0) {
                              // To avoid running into issues with EIP-170 we reuse the handlePayment function (to avoid adjusting code of that has been verified we do not adjust the method itself)
                              // baseGas = 0, gasPrice = 1 and gas = payment => amount = (payment + 0) * 1 = payment
                              handlePayment(payment, 0, 1, paymentToken, paymentReceiver);
                          }
                          emit SafeSetup(msg.sender, _owners, _threshold, to, fallbackHandler);
                      }
                      /// @dev Allows to execute a Safe transaction confirmed by required number of owners and then pays the account that submitted the transaction.
                      ///      Note: The fees are always transferred, even if the user transaction fails.
                      /// @param to Destination address of Safe transaction.
                      /// @param value Ether value of Safe transaction.
                      /// @param data Data payload of Safe transaction.
                      /// @param operation Operation type of Safe transaction.
                      /// @param safeTxGas Gas that should be used for the Safe transaction.
                      /// @param baseGas Gas costs that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
                      /// @param gasPrice Gas price that should be used for the payment calculation.
                      /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
                      /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
                      /// @param signatures Packed signature data ({bytes32 r}{bytes32 s}{uint8 v})
                      function execTransaction(
                          address to,
                          uint256 value,
                          bytes calldata data,
                          Enum.Operation operation,
                          uint256 safeTxGas,
                          uint256 baseGas,
                          uint256 gasPrice,
                          address gasToken,
                          address payable refundReceiver,
                          bytes memory signatures
                      ) public payable virtual returns (bool success) {
                          bytes32 txHash;
                          // Use scope here to limit variable lifetime and prevent `stack too deep` errors
                          {
                              bytes memory txHashData =
                                  encodeTransactionData(
                                      // Transaction info
                                      to,
                                      value,
                                      data,
                                      operation,
                                      safeTxGas,
                                      // Payment info
                                      baseGas,
                                      gasPrice,
                                      gasToken,
                                      refundReceiver,
                                      // Signature info
                                      nonce
                                  );
                              // Increase nonce and execute transaction.
                              nonce++;
                              txHash = keccak256(txHashData);
                              checkSignatures(txHash, txHashData, signatures);
                          }
                          address guard = getGuard();
                          {
                              if (guard != address(0)) {
                                  Guard(guard).checkTransaction(
                                      // Transaction info
                                      to,
                                      value,
                                      data,
                                      operation,
                                      safeTxGas,
                                      // Payment info
                                      baseGas,
                                      gasPrice,
                                      gasToken,
                                      refundReceiver,
                                      // Signature info
                                      signatures,
                                      msg.sender
                                  );
                              }
                          }
                          // We require some gas to emit the events (at least 2500) after the execution and some to perform code until the execution (500)
                          // We also include the 1/64 in the check that is not send along with a call to counteract potential shortings because of EIP-150
                          require(gasleft() >= ((safeTxGas * 64) / 63).max(safeTxGas + 2500) + 500, "GS010");
                          // Use scope here to limit variable lifetime and prevent `stack too deep` errors
                          {
                              uint256 gasUsed = gasleft();
                              // If the gasPrice is 0 we assume that nearly all available gas can be used (it is always more than safeTxGas)
                              // We only substract 2500 (compared to the 3000 before) to ensure that the amount passed is still higher than safeTxGas
                              success = execute(to, value, data, operation, gasPrice == 0 ? (gasleft() - 2500) : safeTxGas);
                              gasUsed = gasUsed.sub(gasleft());
                              // If no safeTxGas and no gasPrice was set (e.g. both are 0), then the internal tx is required to be successful
                              // This makes it possible to use `estimateGas` without issues, as it searches for the minimum gas where the tx doesn't revert
                              require(success || safeTxGas != 0 || gasPrice != 0, "GS013");
                              // We transfer the calculated tx costs to the tx.origin to avoid sending it to intermediate contracts that have made calls
                              uint256 payment = 0;
                              if (gasPrice > 0) {
                                  payment = handlePayment(gasUsed, baseGas, gasPrice, gasToken, refundReceiver);
                              }
                              if (success) emit ExecutionSuccess(txHash, payment);
                              else emit ExecutionFailure(txHash, payment);
                          }
                          {
                              if (guard != address(0)) {
                                  Guard(guard).checkAfterExecution(txHash, success);
                              }
                          }
                      }
                      function handlePayment(
                          uint256 gasUsed,
                          uint256 baseGas,
                          uint256 gasPrice,
                          address gasToken,
                          address payable refundReceiver
                      ) private returns (uint256 payment) {
                          // solhint-disable-next-line avoid-tx-origin
                          address payable receiver = refundReceiver == address(0) ? payable(tx.origin) : refundReceiver;
                          if (gasToken == address(0)) {
                              // For ETH we will only adjust the gas price to not be higher than the actual used gas price
                              payment = gasUsed.add(baseGas).mul(gasPrice < tx.gasprice ? gasPrice : tx.gasprice);
                              require(receiver.send(payment), "GS011");
                          } else {
                              payment = gasUsed.add(baseGas).mul(gasPrice);
                              require(transferToken(gasToken, receiver, payment), "GS012");
                          }
                      }
                      /**
                       * @dev Checks whether the signature provided is valid for the provided data, hash. Will revert otherwise.
                       * @param dataHash Hash of the data (could be either a message hash or transaction hash)
                       * @param data That should be signed (this is passed to an external validator contract)
                       * @param signatures Signature data that should be verified. Can be ECDSA signature, contract signature (EIP-1271) or approved hash.
                       */
                      function checkSignatures(
                          bytes32 dataHash,
                          bytes memory data,
                          bytes memory signatures
                      ) public view {
                          // Load threshold to avoid multiple storage loads
                          uint256 _threshold = threshold;
                          // Check that a threshold is set
                          require(_threshold > 0, "GS001");
                          checkNSignatures(dataHash, data, signatures, _threshold);
                      }
                      /**
                       * @dev Checks whether the signature provided is valid for the provided data, hash. Will revert otherwise.
                       * @param dataHash Hash of the data (could be either a message hash or transaction hash)
                       * @param data That should be signed (this is passed to an external validator contract)
                       * @param signatures Signature data that should be verified. Can be ECDSA signature, contract signature (EIP-1271) or approved hash.
                       * @param requiredSignatures Amount of required valid signatures.
                       */
                      function checkNSignatures(
                          bytes32 dataHash,
                          bytes memory data,
                          bytes memory signatures,
                          uint256 requiredSignatures
                      ) public view {
                          // Check that the provided signature data is not too short
                          require(signatures.length >= requiredSignatures.mul(65), "GS020");
                          // There cannot be an owner with address 0.
                          address lastOwner = address(0);
                          address currentOwner;
                          uint8 v;
                          bytes32 r;
                          bytes32 s;
                          uint256 i;
                          for (i = 0; i < requiredSignatures; i++) {
                              (v, r, s) = signatureSplit(signatures, i);
                              if (v == 0) {
                                  // If v is 0 then it is a contract signature
                                  // When handling contract signatures the address of the contract is encoded into r
                                  currentOwner = address(uint160(uint256(r)));
                                  // Check that signature data pointer (s) is not pointing inside the static part of the signatures bytes
                                  // This check is not completely accurate, since it is possible that more signatures than the threshold are send.
                                  // Here we only check that the pointer is not pointing inside the part that is being processed
                                  require(uint256(s) >= requiredSignatures.mul(65), "GS021");
                                  // Check that signature data pointer (s) is in bounds (points to the length of data -> 32 bytes)
                                  require(uint256(s).add(32) <= signatures.length, "GS022");
                                  // Check if the contract signature is in bounds: start of data is s + 32 and end is start + signature length
                                  uint256 contractSignatureLen;
                                  // solhint-disable-next-line no-inline-assembly
                                  assembly {
                                      contractSignatureLen := mload(add(add(signatures, s), 0x20))
                                  }
                                  require(uint256(s).add(32).add(contractSignatureLen) <= signatures.length, "GS023");
                                  // Check signature
                                  bytes memory contractSignature;
                                  // solhint-disable-next-line no-inline-assembly
                                  assembly {
                                      // The signature data for contract signatures is appended to the concatenated signatures and the offset is stored in s
                                      contractSignature := add(add(signatures, s), 0x20)
                                  }
                                  require(ISignatureValidator(currentOwner).isValidSignature(data, contractSignature) == EIP1271_MAGIC_VALUE, "GS024");
                              } else if (v == 1) {
                                  // If v is 1 then it is an approved hash
                                  // When handling approved hashes the address of the approver is encoded into r
                                  currentOwner = address(uint160(uint256(r)));
                                  // Hashes are automatically approved by the sender of the message or when they have been pre-approved via a separate transaction
                                  require(msg.sender == currentOwner || approvedHashes[currentOwner][dataHash] != 0, "GS025");
                              } else if (v > 30) {
                                  // If v > 30 then default va (27,28) has been adjusted for eth_sign flow
                                  // To support eth_sign and similar we adjust v and hash the messageHash with the Ethereum message prefix before applying ecrecover
                                  currentOwner = ecrecover(keccak256(abi.encodePacked("\\x19Ethereum Signed Message:\
                  32", dataHash)), v - 4, r, s);
                              } else {
                                  // Default is the ecrecover flow with the provided data hash
                                  // Use ecrecover with the messageHash for EOA signatures
                                  currentOwner = ecrecover(dataHash, v, r, s);
                              }
                              require(currentOwner > lastOwner && owners[currentOwner] != address(0) && currentOwner != SENTINEL_OWNERS, "GS026");
                              lastOwner = currentOwner;
                          }
                      }
                      /// @dev Allows to estimate a Safe transaction.
                      ///      This method is only meant for estimation purpose, therefore the call will always revert and encode the result in the revert data.
                      ///      Since the `estimateGas` function includes refunds, call this method to get an estimated of the costs that are deducted from the safe with `execTransaction`
                      /// @param to Destination address of Safe transaction.
                      /// @param value Ether value of Safe transaction.
                      /// @param data Data payload of Safe transaction.
                      /// @param operation Operation type of Safe transaction.
                      /// @return Estimate without refunds and overhead fees (base transaction and payload data gas costs).
                      /// @notice Deprecated in favor of common/StorageAccessible.sol and will be removed in next version.
                      function requiredTxGas(
                          address to,
                          uint256 value,
                          bytes calldata data,
                          Enum.Operation operation
                      ) external returns (uint256) {
                          uint256 startGas = gasleft();
                          // We don't provide an error message here, as we use it to return the estimate
                          require(execute(to, value, data, operation, gasleft()));
                          uint256 requiredGas = startGas - gasleft();
                          // Convert response to string and return via error message
                          revert(string(abi.encodePacked(requiredGas)));
                      }
                      /**
                       * @dev Marks a hash as approved. This can be used to validate a hash that is used by a signature.
                       * @param hashToApprove The hash that should be marked as approved for signatures that are verified by this contract.
                       */
                      function approveHash(bytes32 hashToApprove) external {
                          require(owners[msg.sender] != address(0), "GS030");
                          approvedHashes[msg.sender][hashToApprove] = 1;
                          emit ApproveHash(hashToApprove, msg.sender);
                      }
                      /// @dev Returns the chain id used by this contract.
                      function getChainId() public view returns (uint256) {
                          uint256 id;
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              id := chainid()
                          }
                          return id;
                      }
                      function domainSeparator() public view returns (bytes32) {
                          return keccak256(abi.encode(DOMAIN_SEPARATOR_TYPEHASH, getChainId(), this));
                      }
                      /// @dev Returns the bytes that are hashed to be signed by owners.
                      /// @param to Destination address.
                      /// @param value Ether value.
                      /// @param data Data payload.
                      /// @param operation Operation type.
                      /// @param safeTxGas Gas that should be used for the safe transaction.
                      /// @param baseGas Gas costs for that are independent of the transaction execution(e.g. base transaction fee, signature check, payment of the refund)
                      /// @param gasPrice Maximum gas price that should be used for this transaction.
                      /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
                      /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
                      /// @param _nonce Transaction nonce.
                      /// @return Transaction hash bytes.
                      function encodeTransactionData(
                          address to,
                          uint256 value,
                          bytes calldata data,
                          Enum.Operation operation,
                          uint256 safeTxGas,
                          uint256 baseGas,
                          uint256 gasPrice,
                          address gasToken,
                          address refundReceiver,
                          uint256 _nonce
                      ) public view returns (bytes memory) {
                          bytes32 safeTxHash =
                              keccak256(
                                  abi.encode(
                                      SAFE_TX_TYPEHASH,
                                      to,
                                      value,
                                      keccak256(data),
                                      operation,
                                      safeTxGas,
                                      baseGas,
                                      gasPrice,
                                      gasToken,
                                      refundReceiver,
                                      _nonce
                                  )
                              );
                          return abi.encodePacked(bytes1(0x19), bytes1(0x01), domainSeparator(), safeTxHash);
                      }
                      /// @dev Returns hash to be signed by owners.
                      /// @param to Destination address.
                      /// @param value Ether value.
                      /// @param data Data payload.
                      /// @param operation Operation type.
                      /// @param safeTxGas Fas that should be used for the safe transaction.
                      /// @param baseGas Gas costs for data used to trigger the safe transaction.
                      /// @param gasPrice Maximum gas price that should be used for this transaction.
                      /// @param gasToken Token address (or 0 if ETH) that is used for the payment.
                      /// @param refundReceiver Address of receiver of gas payment (or 0 if tx.origin).
                      /// @param _nonce Transaction nonce.
                      /// @return Transaction hash.
                      function getTransactionHash(
                          address to,
                          uint256 value,
                          bytes calldata data,
                          Enum.Operation operation,
                          uint256 safeTxGas,
                          uint256 baseGas,
                          uint256 gasPrice,
                          address gasToken,
                          address refundReceiver,
                          uint256 _nonce
                      ) public view returns (bytes32) {
                          return keccak256(encodeTransactionData(to, value, data, operation, safeTxGas, baseGas, gasPrice, gasToken, refundReceiver, _nonce));
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  import "../common/Enum.sol";
                  /// @title Executor - A contract that can execute transactions
                  /// @author Richard Meissner - <[email protected]>
                  contract Executor {
                      function execute(
                          address to,
                          uint256 value,
                          bytes memory data,
                          Enum.Operation operation,
                          uint256 txGas
                      ) internal returns (bool success) {
                          if (operation == Enum.Operation.DelegateCall) {
                              // solhint-disable-next-line no-inline-assembly
                              assembly {
                                  success := delegatecall(txGas, to, add(data, 0x20), mload(data), 0, 0)
                              }
                          } else {
                              // solhint-disable-next-line no-inline-assembly
                              assembly {
                                  success := call(txGas, to, value, add(data, 0x20), mload(data), 0, 0)
                              }
                          }
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  import "../common/SelfAuthorized.sol";
                  /// @title Fallback Manager - A contract that manages fallback calls made to this contract
                  /// @author Richard Meissner - <[email protected]>
                  contract FallbackManager is SelfAuthorized {
                      event ChangedFallbackHandler(address handler);
                      // keccak256("fallback_manager.handler.address")
                      bytes32 internal constant FALLBACK_HANDLER_STORAGE_SLOT = 0x6c9a6c4a39284e37ed1cf53d337577d14212a4870fb976a4366c693b939918d5;
                      function internalSetFallbackHandler(address handler) internal {
                          bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              sstore(slot, handler)
                          }
                      }
                      /// @dev Allows to add a contract to handle fallback calls.
                      ///      Only fallback calls without value and with data will be forwarded.
                      ///      This can only be done via a Safe transaction.
                      /// @param handler contract to handle fallbacks calls.
                      function setFallbackHandler(address handler) public authorized {
                          internalSetFallbackHandler(handler);
                          emit ChangedFallbackHandler(handler);
                      }
                      // solhint-disable-next-line payable-fallback,no-complex-fallback
                      fallback() external {
                          bytes32 slot = FALLBACK_HANDLER_STORAGE_SLOT;
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              let handler := sload(slot)
                              if iszero(handler) {
                                  return(0, 0)
                              }
                              calldatacopy(0, 0, calldatasize())
                              // The msg.sender address is shifted to the left by 12 bytes to remove the padding
                              // Then the address without padding is stored right after the calldata
                              mstore(calldatasize(), shl(96, caller()))
                              // Add 20 bytes for the address appended add the end
                              let success := call(gas(), handler, 0, 0, add(calldatasize(), 20), 0, 0)
                              returndatacopy(0, 0, returndatasize())
                              if iszero(success) {
                                  revert(0, returndatasize())
                              }
                              return(0, returndatasize())
                          }
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  import "../common/Enum.sol";
                  import "../common/SelfAuthorized.sol";
                  interface Guard {
                      function checkTransaction(
                          address to,
                          uint256 value,
                          bytes memory data,
                          Enum.Operation operation,
                          uint256 safeTxGas,
                          uint256 baseGas,
                          uint256 gasPrice,
                          address gasToken,
                          address payable refundReceiver,
                          bytes memory signatures,
                          address msgSender
                      ) external;
                      function checkAfterExecution(bytes32 txHash, bool success) external;
                  }
                  /// @title Fallback Manager - A contract that manages fallback calls made to this contract
                  /// @author Richard Meissner - <[email protected]>
                  contract GuardManager is SelfAuthorized {
                      event ChangedGuard(address guard);
                      // keccak256("guard_manager.guard.address")
                      bytes32 internal constant GUARD_STORAGE_SLOT = 0x4a204f620c8c5ccdca3fd54d003badd85ba500436a431f0cbda4f558c93c34c8;
                      /// @dev Set a guard that checks transactions before execution
                      /// @param guard The address of the guard to be used or the 0 address to disable the guard
                      function setGuard(address guard) external authorized {
                          bytes32 slot = GUARD_STORAGE_SLOT;
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              sstore(slot, guard)
                          }
                          emit ChangedGuard(guard);
                      }
                      function getGuard() internal view returns (address guard) {
                          bytes32 slot = GUARD_STORAGE_SLOT;
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              guard := sload(slot)
                          }
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  import "../common/Enum.sol";
                  import "../common/SelfAuthorized.sol";
                  import "./Executor.sol";
                  /// @title Module Manager - A contract that manages modules that can execute transactions via this contract
                  /// @author Stefan George - <[email protected]>
                  /// @author Richard Meissner - <[email protected]>
                  contract ModuleManager is SelfAuthorized, Executor {
                      event EnabledModule(address module);
                      event DisabledModule(address module);
                      event ExecutionFromModuleSuccess(address indexed module);
                      event ExecutionFromModuleFailure(address indexed module);
                      address internal constant SENTINEL_MODULES = address(0x1);
                      mapping(address => address) internal modules;
                      function setupModules(address to, bytes memory data) internal {
                          require(modules[SENTINEL_MODULES] == address(0), "GS100");
                          modules[SENTINEL_MODULES] = SENTINEL_MODULES;
                          if (to != address(0))
                              // Setup has to complete successfully or transaction fails.
                              require(execute(to, 0, data, Enum.Operation.DelegateCall, gasleft()), "GS000");
                      }
                      /// @dev Allows to add a module to the whitelist.
                      ///      This can only be done via a Safe transaction.
                      /// @notice Enables the module `module` for the Safe.
                      /// @param module Module to be whitelisted.
                      function enableModule(address module) public authorized {
                          // Module address cannot be null or sentinel.
                          require(module != address(0) && module != SENTINEL_MODULES, "GS101");
                          // Module cannot be added twice.
                          require(modules[module] == address(0), "GS102");
                          modules[module] = modules[SENTINEL_MODULES];
                          modules[SENTINEL_MODULES] = module;
                          emit EnabledModule(module);
                      }
                      /// @dev Allows to remove a module from the whitelist.
                      ///      This can only be done via a Safe transaction.
                      /// @notice Disables the module `module` for the Safe.
                      /// @param prevModule Module that pointed to the module to be removed in the linked list
                      /// @param module Module to be removed.
                      function disableModule(address prevModule, address module) public authorized {
                          // Validate module address and check that it corresponds to module index.
                          require(module != address(0) && module != SENTINEL_MODULES, "GS101");
                          require(modules[prevModule] == module, "GS103");
                          modules[prevModule] = modules[module];
                          modules[module] = address(0);
                          emit DisabledModule(module);
                      }
                      /// @dev Allows a Module to execute a Safe transaction without any further confirmations.
                      /// @param to Destination address of module transaction.
                      /// @param value Ether value of module transaction.
                      /// @param data Data payload of module transaction.
                      /// @param operation Operation type of module transaction.
                      function execTransactionFromModule(
                          address to,
                          uint256 value,
                          bytes memory data,
                          Enum.Operation operation
                      ) public virtual returns (bool success) {
                          // Only whitelisted modules are allowed.
                          require(msg.sender != SENTINEL_MODULES && modules[msg.sender] != address(0), "GS104");
                          // Execute transaction without further confirmations.
                          success = execute(to, value, data, operation, gasleft());
                          if (success) emit ExecutionFromModuleSuccess(msg.sender);
                          else emit ExecutionFromModuleFailure(msg.sender);
                      }
                      /// @dev Allows a Module to execute a Safe transaction without any further confirmations and return data
                      /// @param to Destination address of module transaction.
                      /// @param value Ether value of module transaction.
                      /// @param data Data payload of module transaction.
                      /// @param operation Operation type of module transaction.
                      function execTransactionFromModuleReturnData(
                          address to,
                          uint256 value,
                          bytes memory data,
                          Enum.Operation operation
                      ) public returns (bool success, bytes memory returnData) {
                          success = execTransactionFromModule(to, value, data, operation);
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              // Load free memory location
                              let ptr := mload(0x40)
                              // We allocate memory for the return data by setting the free memory location to
                              // current free memory location + data size + 32 bytes for data size value
                              mstore(0x40, add(ptr, add(returndatasize(), 0x20)))
                              // Store the size
                              mstore(ptr, returndatasize())
                              // Store the data
                              returndatacopy(add(ptr, 0x20), 0, returndatasize())
                              // Point the return data to the correct memory location
                              returnData := ptr
                          }
                      }
                      /// @dev Returns if an module is enabled
                      /// @return True if the module is enabled
                      function isModuleEnabled(address module) public view returns (bool) {
                          return SENTINEL_MODULES != module && modules[module] != address(0);
                      }
                      /// @dev Returns array of modules.
                      /// @param start Start of the page.
                      /// @param pageSize Maximum number of modules that should be returned.
                      /// @return array Array of modules.
                      /// @return next Start of the next page.
                      function getModulesPaginated(address start, uint256 pageSize) external view returns (address[] memory array, address next) {
                          // Init array with max page size
                          array = new address[](pageSize);
                          // Populate return array
                          uint256 moduleCount = 0;
                          address currentModule = modules[start];
                          while (currentModule != address(0x0) && currentModule != SENTINEL_MODULES && moduleCount < pageSize) {
                              array[moduleCount] = currentModule;
                              currentModule = modules[currentModule];
                              moduleCount++;
                          }
                          next = currentModule;
                          // Set correct size of returned array
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              mstore(array, moduleCount)
                          }
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  import "../common/SelfAuthorized.sol";
                  /// @title OwnerManager - Manages a set of owners and a threshold to perform actions.
                  /// @author Stefan George - <[email protected]>
                  /// @author Richard Meissner - <[email protected]>
                  contract OwnerManager is SelfAuthorized {
                      event AddedOwner(address owner);
                      event RemovedOwner(address owner);
                      event ChangedThreshold(uint256 threshold);
                      address internal constant SENTINEL_OWNERS = address(0x1);
                      mapping(address => address) internal owners;
                      uint256 internal ownerCount;
                      uint256 internal threshold;
                      /// @dev Setup function sets initial storage of contract.
                      /// @param _owners List of Safe owners.
                      /// @param _threshold Number of required confirmations for a Safe transaction.
                      function setupOwners(address[] memory _owners, uint256 _threshold) internal {
                          // Threshold can only be 0 at initialization.
                          // Check ensures that setup function can only be called once.
                          require(threshold == 0, "GS200");
                          // Validate that threshold is smaller than number of added owners.
                          require(_threshold <= _owners.length, "GS201");
                          // There has to be at least one Safe owner.
                          require(_threshold >= 1, "GS202");
                          // Initializing Safe owners.
                          address currentOwner = SENTINEL_OWNERS;
                          for (uint256 i = 0; i < _owners.length; i++) {
                              // Owner address cannot be null.
                              address owner = _owners[i];
                              require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this) && currentOwner != owner, "GS203");
                              // No duplicate owners allowed.
                              require(owners[owner] == address(0), "GS204");
                              owners[currentOwner] = owner;
                              currentOwner = owner;
                          }
                          owners[currentOwner] = SENTINEL_OWNERS;
                          ownerCount = _owners.length;
                          threshold = _threshold;
                      }
                      /// @dev Allows to add a new owner to the Safe and update the threshold at the same time.
                      ///      This can only be done via a Safe transaction.
                      /// @notice Adds the owner `owner` to the Safe and updates the threshold to `_threshold`.
                      /// @param owner New owner address.
                      /// @param _threshold New threshold.
                      function addOwnerWithThreshold(address owner, uint256 _threshold) public authorized {
                          // Owner address cannot be null, the sentinel or the Safe itself.
                          require(owner != address(0) && owner != SENTINEL_OWNERS && owner != address(this), "GS203");
                          // No duplicate owners allowed.
                          require(owners[owner] == address(0), "GS204");
                          owners[owner] = owners[SENTINEL_OWNERS];
                          owners[SENTINEL_OWNERS] = owner;
                          ownerCount++;
                          emit AddedOwner(owner);
                          // Change threshold if threshold was changed.
                          if (threshold != _threshold) changeThreshold(_threshold);
                      }
                      /// @dev Allows to remove an owner from the Safe and update the threshold at the same time.
                      ///      This can only be done via a Safe transaction.
                      /// @notice Removes the owner `owner` from the Safe and updates the threshold to `_threshold`.
                      /// @param prevOwner Owner that pointed to the owner to be removed in the linked list
                      /// @param owner Owner address to be removed.
                      /// @param _threshold New threshold.
                      function removeOwner(
                          address prevOwner,
                          address owner,
                          uint256 _threshold
                      ) public authorized {
                          // Only allow to remove an owner, if threshold can still be reached.
                          require(ownerCount - 1 >= _threshold, "GS201");
                          // Validate owner address and check that it corresponds to owner index.
                          require(owner != address(0) && owner != SENTINEL_OWNERS, "GS203");
                          require(owners[prevOwner] == owner, "GS205");
                          owners[prevOwner] = owners[owner];
                          owners[owner] = address(0);
                          ownerCount--;
                          emit RemovedOwner(owner);
                          // Change threshold if threshold was changed.
                          if (threshold != _threshold) changeThreshold(_threshold);
                      }
                      /// @dev Allows to swap/replace an owner from the Safe with another address.
                      ///      This can only be done via a Safe transaction.
                      /// @notice Replaces the owner `oldOwner` in the Safe with `newOwner`.
                      /// @param prevOwner Owner that pointed to the owner to be replaced in the linked list
                      /// @param oldOwner Owner address to be replaced.
                      /// @param newOwner New owner address.
                      function swapOwner(
                          address prevOwner,
                          address oldOwner,
                          address newOwner
                      ) public authorized {
                          // Owner address cannot be null, the sentinel or the Safe itself.
                          require(newOwner != address(0) && newOwner != SENTINEL_OWNERS && newOwner != address(this), "GS203");
                          // No duplicate owners allowed.
                          require(owners[newOwner] == address(0), "GS204");
                          // Validate oldOwner address and check that it corresponds to owner index.
                          require(oldOwner != address(0) && oldOwner != SENTINEL_OWNERS, "GS203");
                          require(owners[prevOwner] == oldOwner, "GS205");
                          owners[newOwner] = owners[oldOwner];
                          owners[prevOwner] = newOwner;
                          owners[oldOwner] = address(0);
                          emit RemovedOwner(oldOwner);
                          emit AddedOwner(newOwner);
                      }
                      /// @dev Allows to update the number of required confirmations by Safe owners.
                      ///      This can only be done via a Safe transaction.
                      /// @notice Changes the threshold of the Safe to `_threshold`.
                      /// @param _threshold New threshold.
                      function changeThreshold(uint256 _threshold) public authorized {
                          // Validate that threshold is smaller than number of owners.
                          require(_threshold <= ownerCount, "GS201");
                          // There has to be at least one Safe owner.
                          require(_threshold >= 1, "GS202");
                          threshold = _threshold;
                          emit ChangedThreshold(threshold);
                      }
                      function getThreshold() public view returns (uint256) {
                          return threshold;
                      }
                      function isOwner(address owner) public view returns (bool) {
                          return owner != SENTINEL_OWNERS && owners[owner] != address(0);
                      }
                      /// @dev Returns array of owners.
                      /// @return Array of Safe owners.
                      function getOwners() public view returns (address[] memory) {
                          address[] memory array = new address[](ownerCount);
                          // populate return array
                          uint256 index = 0;
                          address currentOwner = owners[SENTINEL_OWNERS];
                          while (currentOwner != SENTINEL_OWNERS) {
                              array[index] = currentOwner;
                              currentOwner = owners[currentOwner];
                              index++;
                          }
                          return array;
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  /// @title Enum - Collection of enums
                  /// @author Richard Meissner - <[email protected]>
                  contract Enum {
                      enum Operation {Call, DelegateCall}
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  /// @title EtherPaymentFallback - A contract that has a fallback to accept ether payments
                  /// @author Richard Meissner - <[email protected]>
                  contract EtherPaymentFallback {
                      event SafeReceived(address indexed sender, uint256 value);
                      /// @dev Fallback function accepts Ether transactions.
                      receive() external payable {
                          emit SafeReceived(msg.sender, msg.value);
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  /// @title SecuredTokenTransfer - Secure token transfer
                  /// @author Richard Meissner - <[email protected]>
                  contract SecuredTokenTransfer {
                      /// @dev Transfers a token and returns if it was a success
                      /// @param token Token that should be transferred
                      /// @param receiver Receiver to whom the token should be transferred
                      /// @param amount The amount of tokens that should be transferred
                      function transferToken(
                          address token,
                          address receiver,
                          uint256 amount
                      ) internal returns (bool transferred) {
                          // 0xa9059cbb - keccack("transfer(address,uint256)")
                          bytes memory data = abi.encodeWithSelector(0xa9059cbb, receiver, amount);
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              // We write the return value to scratch space.
                              // See https://docs.soliditylang.org/en/v0.7.6/internals/layout_in_memory.html#layout-in-memory
                              let success := call(sub(gas(), 10000), token, 0, add(data, 0x20), mload(data), 0, 0x20)
                              switch returndatasize()
                                  case 0 {
                                      transferred := success
                                  }
                                  case 0x20 {
                                      transferred := iszero(or(iszero(success), iszero(mload(0))))
                                  }
                                  default {
                                      transferred := 0
                                  }
                          }
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  /// @title SelfAuthorized - authorizes current contract to perform actions
                  /// @author Richard Meissner - <[email protected]>
                  contract SelfAuthorized {
                      function requireSelfCall() private view {
                          require(msg.sender == address(this), "GS031");
                      }
                      modifier authorized() {
                          // This is a function call as it minimized the bytecode size
                          requireSelfCall();
                          _;
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  /// @title SignatureDecoder - Decodes signatures that a encoded as bytes
                  /// @author Richard Meissner - <[email protected]>
                  contract SignatureDecoder {
                      /// @dev divides bytes signature into `uint8 v, bytes32 r, bytes32 s`.
                      /// @notice Make sure to peform a bounds check for @param pos, to avoid out of bounds access on @param signatures
                      /// @param pos which signature to read. A prior bounds check of this parameter should be performed, to avoid out of bounds access
                      /// @param signatures concatenated rsv signatures
                      function signatureSplit(bytes memory signatures, uint256 pos)
                          internal
                          pure
                          returns (
                              uint8 v,
                              bytes32 r,
                              bytes32 s
                          )
                      {
                          // The signature format is a compact form of:
                          //   {bytes32 r}{bytes32 s}{uint8 v}
                          // Compact means, uint8 is not padded to 32 bytes.
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              let signaturePos := mul(0x41, pos)
                              r := mload(add(signatures, add(signaturePos, 0x20)))
                              s := mload(add(signatures, add(signaturePos, 0x40)))
                              // Here we are loading the last 32 bytes, including 31 bytes
                              // of 's'. There is no 'mload8' to do this.
                              //
                              // 'byte' is not working due to the Solidity parser, so lets
                              // use the second best option, 'and'
                              v := and(mload(add(signatures, add(signaturePos, 0x41))), 0xff)
                          }
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  /// @title Singleton - Base for singleton contracts (should always be first super contract)
                  ///         This contract is tightly coupled to our proxy contract (see `proxies/GnosisSafeProxy.sol`)
                  /// @author Richard Meissner - <[email protected]>
                  contract Singleton {
                      // singleton always needs to be first declared variable, to ensure that it is at the same location as in the Proxy contract.
                      // It should also always be ensured that the address is stored alone (uses a full word)
                      address private singleton;
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  /// @title StorageAccessible - generic base contract that allows callers to access all internal storage.
                  /// @notice See https://github.com/gnosis/util-contracts/blob/bb5fe5fb5df6d8400998094fb1b32a178a47c3a1/contracts/StorageAccessible.sol
                  contract StorageAccessible {
                      /**
                       * @dev Reads `length` bytes of storage in the currents contract
                       * @param offset - the offset in the current contract's storage in words to start reading from
                       * @param length - the number of words (32 bytes) of data to read
                       * @return the bytes that were read.
                       */
                      function getStorageAt(uint256 offset, uint256 length) public view returns (bytes memory) {
                          bytes memory result = new bytes(length * 32);
                          for (uint256 index = 0; index < length; index++) {
                              // solhint-disable-next-line no-inline-assembly
                              assembly {
                                  let word := sload(add(offset, index))
                                  mstore(add(add(result, 0x20), mul(index, 0x20)), word)
                              }
                          }
                          return result;
                      }
                      /**
                       * @dev Performs a delegetecall on a targetContract in the context of self.
                       * Internally reverts execution to avoid side effects (making it static).
                       *
                       * This method reverts with data equal to `abi.encode(bool(success), bytes(response))`.
                       * Specifically, the `returndata` after a call to this method will be:
                       * `success:bool || response.length:uint256 || response:bytes`.
                       *
                       * @param targetContract Address of the contract containing the code to execute.
                       * @param calldataPayload Calldata that should be sent to the target contract (encoded method name and arguments).
                       */
                      function simulateAndRevert(address targetContract, bytes memory calldataPayload) external {
                          // solhint-disable-next-line no-inline-assembly
                          assembly {
                              let success := delegatecall(gas(), targetContract, add(calldataPayload, 0x20), mload(calldataPayload), 0, 0)
                              mstore(0x00, success)
                              mstore(0x20, returndatasize())
                              returndatacopy(0x40, 0, returndatasize())
                              revert(0, add(returndatasize(), 0x40))
                          }
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  /**
                   * @title GnosisSafeMath
                   * @dev Math operations with safety checks that revert on error
                   * Renamed from SafeMath to GnosisSafeMath to avoid conflicts
                   * TODO: remove once open zeppelin update to solc 0.5.0
                   */
                  library GnosisSafeMath {
                      /**
                       * @dev Multiplies two numbers, reverts on overflow.
                       */
                      function mul(uint256 a, uint256 b) internal pure returns (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-solidity/pull/522
                          if (a == 0) {
                              return 0;
                          }
                          uint256 c = a * b;
                          require(c / a == b);
                          return c;
                      }
                      /**
                       * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
                       */
                      function sub(uint256 a, uint256 b) internal pure returns (uint256) {
                          require(b <= a);
                          uint256 c = a - b;
                          return c;
                      }
                      /**
                       * @dev Adds two numbers, reverts on overflow.
                       */
                      function add(uint256 a, uint256 b) internal pure returns (uint256) {
                          uint256 c = a + b;
                          require(c >= a);
                          return c;
                      }
                      /**
                       * @dev Returns the largest of two numbers.
                       */
                      function max(uint256 a, uint256 b) internal pure returns (uint256) {
                          return a >= b ? a : b;
                      }
                  }
                  // SPDX-License-Identifier: LGPL-3.0-only
                  pragma solidity >=0.7.0 <0.9.0;
                  contract ISignatureValidatorConstants {
                      // bytes4(keccak256("isValidSignature(bytes,bytes)")
                      bytes4 internal constant EIP1271_MAGIC_VALUE = 0x20c13b0b;
                  }
                  abstract contract ISignatureValidator is ISignatureValidatorConstants {
                      /**
                       * @dev Should return whether the signature provided is valid for the provided data
                       * @param _data Arbitrary length data signed on the behalf of address(this)
                       * @param _signature Signature byte array associated with _data
                       *
                       * MUST return the bytes4 magic value 0x20c13b0b when function passes.
                       * MUST NOT modify state (using STATICCALL for solc < 0.5, view modifier for solc > 0.5)
                       * MUST allow external calls
                       */
                      function isValidSignature(bytes memory _data, bytes memory _signature) public view virtual returns (bytes4);
                  }