// SPDX-License-Identifier: MIT
pragma solidity 0.8.8;

// @openzeppelin/contracts/utils/Context.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 Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// @openzeppelin/contracts/utils/Address.sol

/**
 * @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
     * ====
     *
     * [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://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");

        (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");

        (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");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason 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 {
            // 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

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// @openzeppelin/contracts/token/ERC20/utils/SafeERC20.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 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'
        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) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _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
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// @openzeppelin/contracts/access/Ownable.sol

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _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);
    }
}

// @openzeppelin/contracts/token/ERC20/IERC20.sol

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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 `from` to `to` 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 from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol

/**
 * @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);
}

interface IOdosExecutor {
  function executePath (
    bytes calldata bytecode,
    uint256[] memory inputAmount
  ) external payable;
}

interface IDaiStylePermit {
    function permit(
      address holder,
      address spender,
      uint256 nonce,
      uint256 expiry,
      bool allowed,
      uint8 v,
      bytes32 r,
      bytes32 s
    ) external;
}

/// @title Routing contract for Odos SOR
/// @author Semiotic AI
/// @notice Wrapper with security gaurentees around execution of arbitrary operations on user tokens
contract OdosRouter is Ownable {
  using SafeERC20 for IERC20;

  /// @dev The zero address is uniquely used to represent eth since it is already
  /// recognized as an invalid ERC20, and due to its gas efficiency
  address constant _ETH = address(0);

  /// @dev Contains all information needed to describe an input token being swapped from
  struct inputToken {
    address tokenAddress;
    uint256 amountIn;
    address receiver;
    bytes permit;
  }
  /// @dev Contains all information needed to describe an output token being swapped to
  struct outputToken {
    address tokenAddress;
    uint256 relativeValue;
    address receiver;
  }
  /// @dev Swap event logging
  event Swapped(
    address sender,
    uint256[] amountsIn,
    address[] tokensIn,
    uint256[] amountsOut,
    outputToken[] outputs,
    uint256 valueOutQuote
  );
  /// @dev Must exist in order for contract to receive eth
  receive() external payable { }

  /// @notice Performs a swap for a given value of some combination of specified output tokens
  /// @param inputs list of input token structs for the path being executed
  /// @param outputs list of output token structs for the path being executed
  /// @param valueOutQuote value of destination tokens quoted for the path
  /// @param valueOutMin minimum amount of value out the user will accept
  /// @param executor Address of contract that will execute the path
  /// @param pathDefinition Encoded path definition for executor
  function swap(
    inputToken[] memory inputs,
    outputToken[] memory outputs,
    uint256 valueOutQuote,
    uint256 valueOutMin,
    address executor,
    bytes calldata pathDefinition
  )
    external
    payable
    returns (uint256[] memory amountsOut, uint256 gasLeft)
  {
    // Check for valid output specifications
    require(valueOutMin <= valueOutQuote, "Minimum greater than quote");
    require(valueOutMin > 0, "Slippage limit too low");

    // Check input specification validity and transfer input tokens to executor
    {
      uint256 expected_msg_value = 0;
      for (uint256 i = 0; i < inputs.length; i++) {
        for (uint256 j = 0; j < i; j++) {
          require(
            inputs[i].tokenAddress != inputs[j].tokenAddress,
            "Duplicate source tokens"
          );
        }
        for (uint256 j = 0; j < outputs.length; j++) {
          require(
            inputs[i].tokenAddress != outputs[j].tokenAddress,
            "Arbitrage not supported"
          );
        }
        if (inputs[i].tokenAddress == _ETH) {
          expected_msg_value = inputs[i].amountIn;
        }
        else {
          _permit(inputs[i].tokenAddress, inputs[i].permit);
          IERC20(inputs[i].tokenAddress).safeTransferFrom(
            msg.sender,
            inputs[i].receiver,
            inputs[i].amountIn
          );
        }
      }
      require(msg.value == expected_msg_value, "Invalid msg.value");
    }
    // Check outputs for duplicates and record balances before swap
    uint256[] memory balancesBefore = new uint256[](outputs.length);
    for (uint256 i = 0; i < outputs.length; i++) {
      for (uint256 j = 0; j < i; j++) {
        require(
          outputs[i].tokenAddress != outputs[j].tokenAddress,
          "Duplicate destination tokens"
        );
      }
      balancesBefore[i] = _universalBalance(outputs[i].tokenAddress);
    }

    // Extract arrays of input amount values and tokens from the inputs struct list
    uint256[] memory amountsIn = new uint256[](inputs.length);
    address[] memory tokensIn = new address[](inputs.length);
    {
      for (uint256 i = 0; i < inputs.length; i++) {
        amountsIn[i] = inputs[i].amountIn;
        tokensIn[i] = inputs[i].tokenAddress;
      }
    }
    // Delegate the execution of the path to the specified Odos Executor
    IOdosExecutor(executor).executePath{value: msg.value}(pathDefinition, amountsIn);
    {
      uint256 valueOut;
      amountsOut = new uint256[](outputs.length);
      for (uint256 i = 0; i < outputs.length; i++) {
        if (valueOut == valueOutQuote) break;

        // Record the destination token balance before the path is executed
        amountsOut[i] = _universalBalance(outputs[i].tokenAddress) - balancesBefore[i];
        valueOut += amountsOut[i] * outputs[i].relativeValue;

        // If the value out excedes the quoted value out, transfer enough to
        // fulfil the quote and break the loop (any other tokens will be over quote)
        if (valueOut > valueOutQuote) {
          amountsOut[i] -= (valueOut - valueOutQuote) / outputs[i].relativeValue;
          valueOut = valueOutQuote;
        }
        _universalTransfer(
          outputs[i].tokenAddress,
          outputs[i].receiver,
          amountsOut[i]
        );
      }
      require(valueOut > valueOutMin, "Slippage Limit Exceeded");
    }
    emit Swapped(
      msg.sender,
      amountsIn,
      tokensIn,
      amountsOut,
      outputs,
      valueOutQuote
    );
    gasLeft = gasleft();
  }
  /// @notice Allows the owner to transfer funds held by the router contract
  /// @param tokens List of token address to be transferred
  /// @param amounts List of amounts of each token to be transferred
  /// @param dest Address to which the funds should be sent
  function transferFunds(
    address[] calldata tokens,
    uint256[] calldata amounts,
    address dest
  )
    external
    onlyOwner
  {
    require(tokens.length == amounts.length, "Invalid funds transfer");
    for (uint256 i = 0; i < tokens.length; i++) {
      _universalTransfer(tokens[i], dest, amounts[i]);
    }
  }
  /// @notice helper function to get balance of ERC20 or native coin for this contract
  /// @param token address of the token to check, null for native coin
  /// @return balance of specified coin or token
  function _universalBalance(address token) private view returns(uint256) {
    if (token == _ETH) {
      return address(this).balance;
    } else {
      return IERC20(token).balanceOf(address(this));
    }
  }
  /// @notice helper function to transfer ERC20 or native coin
  /// @param token address of the token being transferred, null for native coin
  /// @param to address to transfer to
  /// @param amount to transfer
  function _universalTransfer(address token, address to, uint256 amount) private {
    if (token == _ETH) {
      (bool success,) = payable(to).call{value: amount}("");
      require(success, "ETH transfer failed");
    } else {
      IERC20(token).safeTransfer(to, amount);
    }
  }
  /// @notice Executes an ERC20 or Dai Style Permit
  /// @param token address of token permit is for
  /// @param permit the byte information for permit execution, 0 for no operation
  function _permit(address token, bytes memory permit) internal {
    if (permit.length > 0) {
      if (permit.length == 32 * 7) {
        (bool success,) = token.call(abi.encodePacked(IERC20Permit.permit.selector, permit));
        require(success, "IERC20Permit failed");
      } else if (permit.length == 32 * 8) {
        (bool success,) = token.call(abi.encodePacked(IDaiStylePermit.permit.selector, permit));
        require(success, "Dai Style Permit failed");
      } else {
        revert("Invalid Permit");
      }
    }
  }
}

# @title Uniswap Exchange Interface V1
# @notice Source code found at https://github.com/uniswap
# @notice Use at your own risk

contract Factory():
    def getExchange(token_addr: address) -> address: constant

contract Exchange():
    def getEthToTokenOutputPrice(tokens_bought: uint256) -> uint256(wei): constant
    def ethToTokenTransferInput(min_tokens: uint256, deadline: timestamp, recipient: address) -> uint256: modifying
    def ethToTokenTransferOutput(tokens_bought: uint256, deadline: timestamp, recipient: address) -> uint256(wei): modifying

TokenPurchase: event({buyer: indexed(address), eth_sold: indexed(uint256(wei)), tokens_bought: indexed(uint256)})
EthPurchase: event({buyer: indexed(address), tokens_sold: indexed(uint256), eth_bought: indexed(uint256(wei))})
AddLiquidity: event({provider: indexed(address), eth_amount: indexed(uint256(wei)), token_amount: indexed(uint256)})
RemoveLiquidity: event({provider: indexed(address), eth_amount: indexed(uint256(wei)), token_amount: indexed(uint256)})
Transfer: event({_from: indexed(address), _to: indexed(address), _value: uint256})
Approval: event({_owner: indexed(address), _spender: indexed(address), _value: uint256})

name: public(bytes32)                             # Uniswap V1
symbol: public(bytes32)                           # UNI-V1
decimals: public(uint256)                         # 18
totalSupply: public(uint256)                      # total number of UNI in existence
balances: uint256[address]                        # UNI balance of an address
allowances: (uint256[address])[address]           # UNI allowance of one address on another
token: address(ERC20)                             # address of the ERC20 token traded on this contract
factory: Factory                                  # interface for the factory that created this contract

# @dev This function acts as a contract constructor which is not currently supported in contracts deployed
#      using create_with_code_of(). It is called once by the factory during contract creation.
@public
def setup(token_addr: address):
    assert (self.factory == ZERO_ADDRESS and self.token == ZERO_ADDRESS) and token_addr != ZERO_ADDRESS
    self.factory = msg.sender
    self.token = token_addr
    self.name = 0x556e697377617020563100000000000000000000000000000000000000000000
    self.symbol = 0x554e492d56310000000000000000000000000000000000000000000000000000
    self.decimals = 18

# @notice Deposit ETH and Tokens (self.token) at current ratio to mint UNI tokens.
# @dev min_liquidity does nothing when total UNI supply is 0.
# @param min_liquidity Minimum number of UNI sender will mint if total UNI supply is greater than 0.
# @param max_tokens Maximum number of tokens deposited. Deposits max amount if total UNI supply is 0.
# @param deadline Time after which this transaction can no longer be executed.
# @return The amount of UNI minted.
@public
@payable
def addLiquidity(min_liquidity: uint256, max_tokens: uint256, deadline: timestamp) -> uint256:
    assert deadline > block.timestamp and (max_tokens > 0 and msg.value > 0)
    total_liquidity: uint256 = self.totalSupply
    if total_liquidity > 0:
        assert min_liquidity > 0
        eth_reserve: uint256(wei) = self.balance - msg.value
        token_reserve: uint256 = self.token.balanceOf(self)
        token_amount: uint256 = msg.value * token_reserve / eth_reserve + 1
        liquidity_minted: uint256 = msg.value * total_liquidity / eth_reserve
        assert max_tokens >= token_amount and liquidity_minted >= min_liquidity
        self.balances[msg.sender] += liquidity_minted
        self.totalSupply = total_liquidity + liquidity_minted
        assert self.token.transferFrom(msg.sender, self, token_amount)
        log.AddLiquidity(msg.sender, msg.value, token_amount)
        log.Transfer(ZERO_ADDRESS, msg.sender, liquidity_minted)
        return liquidity_minted
    else:
        assert (self.factory != ZERO_ADDRESS and self.token != ZERO_ADDRESS) and msg.value >= 1000000000
        assert self.factory.getExchange(self.token) == self
        token_amount: uint256 = max_tokens
        initial_liquidity: uint256 = as_unitless_number(self.balance)
        self.totalSupply = initial_liquidity
        self.balances[msg.sender] = initial_liquidity
        assert self.token.transferFrom(msg.sender, self, token_amount)
        log.AddLiquidity(msg.sender, msg.value, token_amount)
        log.Transfer(ZERO_ADDRESS, msg.sender, initial_liquidity)
        return initial_liquidity

# @dev Burn UNI tokens to withdraw ETH and Tokens at current ratio.
# @param amount Amount of UNI burned.
# @param min_eth Minimum ETH withdrawn.
# @param min_tokens Minimum Tokens withdrawn.
# @param deadline Time after which this transaction can no longer be executed.
# @return The amount of ETH and Tokens withdrawn.
@public
def removeLiquidity(amount: uint256, min_eth: uint256(wei), min_tokens: uint256, deadline: timestamp) -> (uint256(wei), uint256):
    assert (amount > 0 and deadline > block.timestamp) and (min_eth > 0 and min_tokens > 0)
    total_liquidity: uint256 = self.totalSupply
    assert total_liquidity > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_amount: uint256(wei) = amount * self.balance / total_liquidity
    token_amount: uint256 = amount * token_reserve / total_liquidity
    assert eth_amount >= min_eth and token_amount >= min_tokens
    self.balances[msg.sender] -= amount
    self.totalSupply = total_liquidity - amount
    send(msg.sender, eth_amount)
    assert self.token.transfer(msg.sender, token_amount)
    log.RemoveLiquidity(msg.sender, eth_amount, token_amount)
    log.Transfer(msg.sender, ZERO_ADDRESS, amount)
    return eth_amount, token_amount

# @dev Pricing function for converting between ETH and Tokens.
# @param input_amount Amount of ETH or Tokens being sold.
# @param input_reserve Amount of ETH or Tokens (input type) in exchange reserves.
# @param output_reserve Amount of ETH or Tokens (output type) in exchange reserves.
# @return Amount of ETH or Tokens bought.
@private
@constant
def getInputPrice(input_amount: uint256, input_reserve: uint256, output_reserve: uint256) -> uint256:
    assert input_reserve > 0 and output_reserve > 0
    input_amount_with_fee: uint256 = input_amount * 997
    numerator: uint256 = input_amount_with_fee * output_reserve
    denominator: uint256 = (input_reserve * 1000) + input_amount_with_fee
    return numerator / denominator

# @dev Pricing function for converting between ETH and Tokens.
# @param output_amount Amount of ETH or Tokens being bought.
# @param input_reserve Amount of ETH or Tokens (input type) in exchange reserves.
# @param output_reserve Amount of ETH or Tokens (output type) in exchange reserves.
# @return Amount of ETH or Tokens sold.
@private
@constant
def getOutputPrice(output_amount: uint256, input_reserve: uint256, output_reserve: uint256) -> uint256:
    assert input_reserve > 0 and output_reserve > 0
    numerator: uint256 = input_reserve * output_amount * 1000
    denominator: uint256 = (output_reserve - output_amount) * 997
    return numerator / denominator + 1

@private
def ethToTokenInput(eth_sold: uint256(wei), min_tokens: uint256, deadline: timestamp, buyer: address, recipient: address) -> uint256:
    assert deadline >= block.timestamp and (eth_sold > 0 and min_tokens > 0)
    token_reserve: uint256 = self.token.balanceOf(self)
    tokens_bought: uint256 = self.getInputPrice(as_unitless_number(eth_sold), as_unitless_number(self.balance - eth_sold), token_reserve)
    assert tokens_bought >= min_tokens
    assert self.token.transfer(recipient, tokens_bought)
    log.TokenPurchase(buyer, eth_sold, tokens_bought)
    return tokens_bought

# @notice Convert ETH to Tokens.
# @dev User specifies exact input (msg.value).
# @dev User cannot specify minimum output or deadline.
@public
@payable
def __default__():
    self.ethToTokenInput(msg.value, 1, block.timestamp, msg.sender, msg.sender)

# @notice Convert ETH to Tokens.
# @dev User specifies exact input (msg.value) and minimum output.
# @param min_tokens Minimum Tokens bought.
# @param deadline Time after which this transaction can no longer be executed.
# @return Amount of Tokens bought.
@public
@payable
def ethToTokenSwapInput(min_tokens: uint256, deadline: timestamp) -> uint256:
    return self.ethToTokenInput(msg.value, min_tokens, deadline, msg.sender, msg.sender)

# @notice Convert ETH to Tokens and transfers Tokens to recipient.
# @dev User specifies exact input (msg.value) and minimum output
# @param min_tokens Minimum Tokens bought.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output Tokens.
# @return Amount of Tokens bought.
@public
@payable
def ethToTokenTransferInput(min_tokens: uint256, deadline: timestamp, recipient: address) -> uint256:
    assert recipient != self and recipient != ZERO_ADDRESS
    return self.ethToTokenInput(msg.value, min_tokens, deadline, msg.sender, recipient)

@private
def ethToTokenOutput(tokens_bought: uint256, max_eth: uint256(wei), deadline: timestamp, buyer: address, recipient: address) -> uint256(wei):
    assert deadline >= block.timestamp and (tokens_bought > 0 and max_eth > 0)
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_sold: uint256 = self.getOutputPrice(tokens_bought, as_unitless_number(self.balance - max_eth), token_reserve)
    # Throws if eth_sold > max_eth
    eth_refund: uint256(wei) = max_eth - as_wei_value(eth_sold, 'wei')
    if eth_refund > 0:
        send(buyer, eth_refund)
    assert self.token.transfer(recipient, tokens_bought)
    log.TokenPurchase(buyer, as_wei_value(eth_sold, 'wei'), tokens_bought)
    return as_wei_value(eth_sold, 'wei')

# @notice Convert ETH to Tokens.
# @dev User specifies maximum input (msg.value) and exact output.
# @param tokens_bought Amount of tokens bought.
# @param deadline Time after which this transaction can no longer be executed.
# @return Amount of ETH sold.
@public
@payable
def ethToTokenSwapOutput(tokens_bought: uint256, deadline: timestamp) -> uint256(wei):
    return self.ethToTokenOutput(tokens_bought, msg.value, deadline, msg.sender, msg.sender)

# @notice Convert ETH to Tokens and transfers Tokens to recipient.
# @dev User specifies maximum input (msg.value) and exact output.
# @param tokens_bought Amount of tokens bought.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output Tokens.
# @return Amount of ETH sold.
@public
@payable
def ethToTokenTransferOutput(tokens_bought: uint256, deadline: timestamp, recipient: address) -> uint256(wei):
    assert recipient != self and recipient != ZERO_ADDRESS
    return self.ethToTokenOutput(tokens_bought, msg.value, deadline, msg.sender, recipient)

@private
def tokenToEthInput(tokens_sold: uint256, min_eth: uint256(wei), deadline: timestamp, buyer: address, recipient: address) -> uint256(wei):
    assert deadline >= block.timestamp and (tokens_sold > 0 and min_eth > 0)
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_bought: uint256 = self.getInputPrice(tokens_sold, token_reserve, as_unitless_number(self.balance))
    wei_bought: uint256(wei) = as_wei_value(eth_bought, 'wei')
    assert wei_bought >= min_eth
    send(recipient, wei_bought)
    assert self.token.transferFrom(buyer, self, tokens_sold)
    log.EthPurchase(buyer, tokens_sold, wei_bought)
    return wei_bought


# @notice Convert Tokens to ETH.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_eth Minimum ETH purchased.
# @param deadline Time after which this transaction can no longer be executed.
# @return Amount of ETH bought.
@public
def tokenToEthSwapInput(tokens_sold: uint256, min_eth: uint256(wei), deadline: timestamp) -> uint256(wei):
    return self.tokenToEthInput(tokens_sold, min_eth, deadline, msg.sender, msg.sender)

# @notice Convert Tokens to ETH and transfers ETH to recipient.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_eth Minimum ETH purchased.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @return Amount of ETH bought.
@public
def tokenToEthTransferInput(tokens_sold: uint256, min_eth: uint256(wei), deadline: timestamp, recipient: address) -> uint256(wei):
    assert recipient != self and recipient != ZERO_ADDRESS
    return self.tokenToEthInput(tokens_sold, min_eth, deadline, msg.sender, recipient)

@private
def tokenToEthOutput(eth_bought: uint256(wei), max_tokens: uint256, deadline: timestamp, buyer: address, recipient: address) -> uint256:
    assert deadline >= block.timestamp and eth_bought > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    tokens_sold: uint256 = self.getOutputPrice(as_unitless_number(eth_bought), token_reserve, as_unitless_number(self.balance))
    # tokens sold is always > 0
    assert max_tokens >= tokens_sold
    send(recipient, eth_bought)
    assert self.token.transferFrom(buyer, self, tokens_sold)
    log.EthPurchase(buyer, tokens_sold, eth_bought)
    return tokens_sold

# @notice Convert Tokens to ETH.
# @dev User specifies maximum input and exact output.
# @param eth_bought Amount of ETH purchased.
# @param max_tokens Maximum Tokens sold.
# @param deadline Time after which this transaction can no longer be executed.
# @return Amount of Tokens sold.
@public
def tokenToEthSwapOutput(eth_bought: uint256(wei), max_tokens: uint256, deadline: timestamp) -> uint256:
    return self.tokenToEthOutput(eth_bought, max_tokens, deadline, msg.sender, msg.sender)

# @notice Convert Tokens to ETH and transfers ETH to recipient.
# @dev User specifies maximum input and exact output.
# @param eth_bought Amount of ETH purchased.
# @param max_tokens Maximum Tokens sold.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @return Amount of Tokens sold.
@public
def tokenToEthTransferOutput(eth_bought: uint256(wei), max_tokens: uint256, deadline: timestamp, recipient: address) -> uint256:
    assert recipient != self and recipient != ZERO_ADDRESS
    return self.tokenToEthOutput(eth_bought, max_tokens, deadline, msg.sender, recipient)

@private
def tokenToTokenInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, buyer: address, recipient: address, exchange_addr: address) -> uint256:
    assert (deadline >= block.timestamp and tokens_sold > 0) and (min_tokens_bought > 0 and min_eth_bought > 0)
    assert exchange_addr != self and exchange_addr != ZERO_ADDRESS
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_bought: uint256 = self.getInputPrice(tokens_sold, token_reserve, as_unitless_number(self.balance))
    wei_bought: uint256(wei) = as_wei_value(eth_bought, 'wei')
    assert wei_bought >= min_eth_bought
    assert self.token.transferFrom(buyer, self, tokens_sold)
    tokens_bought: uint256 = Exchange(exchange_addr).ethToTokenTransferInput(min_tokens_bought, deadline, recipient, value=wei_bought)
    log.EthPurchase(buyer, tokens_sold, wei_bought)
    return tokens_bought

# @notice Convert Tokens (self.token) to Tokens (token_addr).
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_tokens_bought Minimum Tokens (token_addr) purchased.
# @param min_eth_bought Minimum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (token_addr) bought.
@public
def tokenToTokenSwapInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, token_addr: address) -> uint256:
    exchange_addr: address = self.factory.getExchange(token_addr)
    return self.tokenToTokenInput(tokens_sold, min_tokens_bought, min_eth_bought, deadline, msg.sender, msg.sender, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (token_addr) and transfers
#         Tokens (token_addr) to recipient.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_tokens_bought Minimum Tokens (token_addr) purchased.
# @param min_eth_bought Minimum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (token_addr) bought.
@public
def tokenToTokenTransferInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, recipient: address, token_addr: address) -> uint256:
    exchange_addr: address = self.factory.getExchange(token_addr)
    return self.tokenToTokenInput(tokens_sold, min_tokens_bought, min_eth_bought, deadline, msg.sender, recipient, exchange_addr)

@private
def tokenToTokenOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, buyer: address, recipient: address, exchange_addr: address) -> uint256:
    assert deadline >= block.timestamp and (tokens_bought > 0 and max_eth_sold > 0)
    assert exchange_addr != self and exchange_addr != ZERO_ADDRESS
    eth_bought: uint256(wei) = Exchange(exchange_addr).getEthToTokenOutputPrice(tokens_bought)
    token_reserve: uint256 = self.token.balanceOf(self)
    tokens_sold: uint256 = self.getOutputPrice(as_unitless_number(eth_bought), token_reserve, as_unitless_number(self.balance))
    # tokens sold is always > 0
    assert max_tokens_sold >= tokens_sold and max_eth_sold >= eth_bought
    assert self.token.transferFrom(buyer, self, tokens_sold)
    eth_sold: uint256(wei) = Exchange(exchange_addr).ethToTokenTransferOutput(tokens_bought, deadline, recipient, value=eth_bought)
    log.EthPurchase(buyer, tokens_sold, eth_bought)
    return tokens_sold

# @notice Convert Tokens (self.token) to Tokens (token_addr).
# @dev User specifies maximum input and exact output.
# @param tokens_bought Amount of Tokens (token_addr) bought.
# @param max_tokens_sold Maximum Tokens (self.token) sold.
# @param max_eth_sold Maximum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (self.token) sold.
@public
def tokenToTokenSwapOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, token_addr: address) -> uint256:
    exchange_addr: address = self.factory.getExchange(token_addr)
    return self.tokenToTokenOutput(tokens_bought, max_tokens_sold, max_eth_sold, deadline, msg.sender, msg.sender, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (token_addr) and transfers
#         Tokens (token_addr) to recipient.
# @dev User specifies maximum input and exact output.
# @param tokens_bought Amount of Tokens (token_addr) bought.
# @param max_tokens_sold Maximum Tokens (self.token) sold.
# @param max_eth_sold Maximum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (self.token) sold.
@public
def tokenToTokenTransferOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, recipient: address, token_addr: address) -> uint256:
    exchange_addr: address = self.factory.getExchange(token_addr)
    return self.tokenToTokenOutput(tokens_bought, max_tokens_sold, max_eth_sold, deadline, msg.sender, recipient, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (exchange_addr.token).
# @dev Allows trades through contracts that were not deployed from the same factory.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_tokens_bought Minimum Tokens (token_addr) purchased.
# @param min_eth_bought Minimum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param exchange_addr The address of the exchange for the token being purchased.
# @return Amount of Tokens (exchange_addr.token) bought.
@public
def tokenToExchangeSwapInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, exchange_addr: address) -> uint256:
    return self.tokenToTokenInput(tokens_sold, min_tokens_bought, min_eth_bought, deadline, msg.sender, msg.sender, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (exchange_addr.token) and transfers
#         Tokens (exchange_addr.token) to recipient.
# @dev Allows trades through contracts that were not deployed from the same factory.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_tokens_bought Minimum Tokens (token_addr) purchased.
# @param min_eth_bought Minimum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @param exchange_addr The address of the exchange for the token being purchased.
# @return Amount of Tokens (exchange_addr.token) bought.
@public
def tokenToExchangeTransferInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, recipient: address, exchange_addr: address) -> uint256:
    assert recipient != self
    return self.tokenToTokenInput(tokens_sold, min_tokens_bought, min_eth_bought, deadline, msg.sender, recipient, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (exchange_addr.token).
# @dev Allows trades through contracts that were not deployed from the same factory.
# @dev User specifies maximum input and exact output.
# @param tokens_bought Amount of Tokens (token_addr) bought.
# @param max_tokens_sold Maximum Tokens (self.token) sold.
# @param max_eth_sold Maximum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param exchange_addr The address of the exchange for the token being purchased.
# @return Amount of Tokens (self.token) sold.
@public
def tokenToExchangeSwapOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, exchange_addr: address) -> uint256:
    return self.tokenToTokenOutput(tokens_bought, max_tokens_sold, max_eth_sold, deadline, msg.sender, msg.sender, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (exchange_addr.token) and transfers
#         Tokens (exchange_addr.token) to recipient.
# @dev Allows trades through contracts that were not deployed from the same factory.
# @dev User specifies maximum input and exact output.
# @param tokens_bought Amount of Tokens (token_addr) bought.
# @param max_tokens_sold Maximum Tokens (self.token) sold.
# @param max_eth_sold Maximum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (self.token) sold.
@public
def tokenToExchangeTransferOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, recipient: address, exchange_addr: address) -> uint256:
    assert recipient != self
    return self.tokenToTokenOutput(tokens_bought, max_tokens_sold, max_eth_sold, deadline, msg.sender, recipient, exchange_addr)

# @notice Public price function for ETH to Token trades with an exact input.
# @param eth_sold Amount of ETH sold.
# @return Amount of Tokens that can be bought with input ETH.
@public
@constant
def getEthToTokenInputPrice(eth_sold: uint256(wei)) -> uint256:
    assert eth_sold > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    return self.getInputPrice(as_unitless_number(eth_sold), as_unitless_number(self.balance), token_reserve)

# @notice Public price function for ETH to Token trades with an exact output.
# @param tokens_bought Amount of Tokens bought.
# @return Amount of ETH needed to buy output Tokens.
@public
@constant
def getEthToTokenOutputPrice(tokens_bought: uint256) -> uint256(wei):
    assert tokens_bought > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_sold: uint256 = self.getOutputPrice(tokens_bought, as_unitless_number(self.balance), token_reserve)
    return as_wei_value(eth_sold, 'wei')

# @notice Public price function for Token to ETH trades with an exact input.
# @param tokens_sold Amount of Tokens sold.
# @return Amount of ETH that can be bought with input Tokens.
@public
@constant
def getTokenToEthInputPrice(tokens_sold: uint256) -> uint256(wei):
    assert tokens_sold > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_bought: uint256 = self.getInputPrice(tokens_sold, token_reserve, as_unitless_number(self.balance))
    return as_wei_value(eth_bought, 'wei')

# @notice Public price function for Token to ETH trades with an exact output.
# @param eth_bought Amount of output ETH.
# @return Amount of Tokens needed to buy output ETH.
@public
@constant
def getTokenToEthOutputPrice(eth_bought: uint256(wei)) -> uint256:
    assert eth_bought > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    return self.getOutputPrice(as_unitless_number(eth_bought), token_reserve, as_unitless_number(self.balance))

# @return Address of Token that is sold on this exchange.
@public
@constant
def tokenAddress() -> address:
    return self.token

# @return Address of factory that created this exchange.
@public
@constant
def factoryAddress() -> address(Factory):
    return self.factory

# ERC20 compatibility for exchange liquidity modified from
# https://github.com/ethereum/vyper/blob/master/examples/tokens/ERC20.vy
@public
@constant
def balanceOf(_owner : address) -> uint256:
    return self.balances[_owner]

@public
def transfer(_to : address, _value : uint256) -> bool:
    self.balances[msg.sender] -= _value
    self.balances[_to] += _value
    log.Transfer(msg.sender, _to, _value)
    return True

@public
def transferFrom(_from : address, _to : address, _value : uint256) -> bool:
    self.balances[_from] -= _value
    self.balances[_to] += _value
    self.allowances[_from][msg.sender] -= _value
    log.Transfer(_from, _to, _value)
    return True

@public
def approve(_spender : address, _value : uint256) -> bool:
    self.allowances[msg.sender][_spender] = _value
    log.Approval(msg.sender, _spender, _value)
    return True

@public
@constant
def allowance(_owner : address, _spender : address) -> uint256:
    return self.allowances[_owner][_spender]

// hevm: flattened sources of /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/dai.sol
pragma solidity =0.5.12;

////// /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/lib.sol
// 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 0.5.12; */

contract LibNote {
    event LogNote(
        bytes4   indexed  sig,
        address  indexed  usr,
        bytes32  indexed  arg1,
        bytes32  indexed  arg2,
        bytes             data
    ) anonymous;

    modifier note {
        _;
        assembly {
            // log an 'anonymous' event with a constant 6 words of calldata
            // and four indexed topics: selector, caller, arg1 and arg2
            let mark := msize                         // end of memory ensures zero
            mstore(0x40, add(mark, 288))              // update free memory pointer
            mstore(mark, 0x20)                        // bytes type data offset
            mstore(add(mark, 0x20), 224)              // bytes size (padded)
            calldatacopy(add(mark, 0x40), 0, 224)     // bytes payload
            log4(mark, 288,                           // calldata
                 shl(224, shr(224, calldataload(0))), // msg.sig
                 caller,                              // msg.sender
                 calldataload(4),                     // arg1
                 calldataload(36)                     // arg2
                )
        }
    }
}

////// /nix/store/8xb41r4qd0cjb63wcrxf1qmfg88p0961-dss-6fd7de0/src/dai.sol
// Copyright (C) 2017, 2018, 2019 dbrock, rain, mrchico

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

/* pragma solidity 0.5.12; */

/* import "./lib.sol"; */

contract Dai is LibNote {
    // --- Auth ---
    mapping (address => uint) public wards;
    function rely(address guy) external note auth { wards[guy] = 1; }
    function deny(address guy) external note auth { wards[guy] = 0; }
    modifier auth {
        require(wards[msg.sender] == 1, "Dai/not-authorized");
        _;
    }

    // --- ERC20 Data ---
    string  public constant name     = "Dai Stablecoin";
    string  public constant symbol   = "DAI";
    string  public constant version  = "1";
    uint8   public constant decimals = 18;
    uint256 public totalSupply;

    mapping (address => uint)                      public balanceOf;
    mapping (address => mapping (address => uint)) public allowance;
    mapping (address => uint)                      public nonces;

    event Approval(address indexed src, address indexed guy, uint wad);
    event Transfer(address indexed src, address indexed dst, uint wad);

    // --- Math ---
    function add(uint x, uint y) internal pure returns (uint z) {
        require((z = x + y) >= x);
    }
    function sub(uint x, uint y) internal pure returns (uint z) {
        require((z = x - y) <= x);
    }

    // --- EIP712 niceties ---
    bytes32 public DOMAIN_SEPARATOR;
    // bytes32 public constant PERMIT_TYPEHASH = keccak256("Permit(address holder,address spender,uint256 nonce,uint256 expiry,bool allowed)");
    bytes32 public constant PERMIT_TYPEHASH = 0xea2aa0a1be11a07ed86d755c93467f4f82362b452371d1ba94d1715123511acb;

    constructor(uint256 chainId_) public {
        wards[msg.sender] = 1;
        DOMAIN_SEPARATOR = keccak256(abi.encode(
            keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
            keccak256(bytes(name)),
            keccak256(bytes(version)),
            chainId_,
            address(this)
        ));
    }

    // --- Token ---
    function transfer(address dst, uint wad) external returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }
    function transferFrom(address src, address dst, uint wad)
        public returns (bool)
    {
        require(balanceOf[src] >= wad, "Dai/insufficient-balance");
        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad, "Dai/insufficient-allowance");
            allowance[src][msg.sender] = sub(allowance[src][msg.sender], wad);
        }
        balanceOf[src] = sub(balanceOf[src], wad);
        balanceOf[dst] = add(balanceOf[dst], wad);
        emit Transfer(src, dst, wad);
        return true;
    }
    function mint(address usr, uint wad) external auth {
        balanceOf[usr] = add(balanceOf[usr], wad);
        totalSupply    = add(totalSupply, wad);
        emit Transfer(address(0), usr, wad);
    }
    function burn(address usr, uint wad) external {
        require(balanceOf[usr] >= wad, "Dai/insufficient-balance");
        if (usr != msg.sender && allowance[usr][msg.sender] != uint(-1)) {
            require(allowance[usr][msg.sender] >= wad, "Dai/insufficient-allowance");
            allowance[usr][msg.sender] = sub(allowance[usr][msg.sender], wad);
        }
        balanceOf[usr] = sub(balanceOf[usr], wad);
        totalSupply    = sub(totalSupply, wad);
        emit Transfer(usr, address(0), wad);
    }
    function approve(address usr, uint wad) external returns (bool) {
        allowance[msg.sender][usr] = wad;
        emit Approval(msg.sender, usr, wad);
        return true;
    }

    // --- Alias ---
    function push(address usr, uint wad) external {
        transferFrom(msg.sender, usr, wad);
    }
    function pull(address usr, uint wad) external {
        transferFrom(usr, msg.sender, wad);
    }
    function move(address src, address dst, uint wad) external {
        transferFrom(src, dst, wad);
    }

    // --- Approve by signature ---
    function permit(address holder, address spender, uint256 nonce, uint256 expiry,
                    bool allowed, uint8 v, bytes32 r, bytes32 s) external
    {
        bytes32 digest =
            keccak256(abi.encodePacked(
                "\x19\x01",
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH,
                                     holder,
                                     spender,
                                     nonce,
                                     expiry,
                                     allowed))
        ));

        require(holder != address(0), "Dai/invalid-address-0");
        require(holder == ecrecover(digest, v, r, s), "Dai/invalid-permit");
        require(expiry == 0 || now <= expiry, "Dai/permit-expired");
        require(nonce == nonces[holder]++, "Dai/invalid-nonce");
        uint wad = allowed ? uint(-1) : 0;
        allowance[holder][spender] = wad;
        emit Approval(holder, spender, wad);
    }
}

{"BColor.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\ncontract BColor {\n    function getColor()\n        external view\n        returns (bytes32);\n}\n\ncontract BBronze is BColor {\n    function getColor()\n        external view\n        returns (bytes32) {\n            return bytes32(\"BRONZE\");\n        }\n}\n"},"BConst.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BColor.sol\";\n\ncontract BConst is BBronze {\n    uint public constant BONE              = 10**18;\n\n    uint public constant MIN_BOUND_TOKENS  = 2;\n    uint public constant MAX_BOUND_TOKENS  = 8;\n\n    uint public constant MIN_FEE           = BONE / 10**6;\n    uint public constant MAX_FEE           = BONE / 10;\n    uint public constant EXIT_FEE          = 0;\n\n    uint public constant MIN_WEIGHT        = BONE;\n    uint public constant MAX_WEIGHT        = BONE * 50;\n    uint public constant MAX_TOTAL_WEIGHT  = BONE * 50;\n    uint public constant MIN_BALANCE       = BONE / 10**12;\n\n    uint public constant INIT_POOL_SUPPLY  = BONE * 100;\n\n    uint public constant MIN_BPOW_BASE     = 1 wei;\n    uint public constant MAX_BPOW_BASE     = (2 * BONE) - 1 wei;\n    uint public constant BPOW_PRECISION    = BONE / 10**10;\n\n    uint public constant MAX_IN_RATIO      = BONE / 2;\n    uint public constant MAX_OUT_RATIO     = (BONE / 3) + 1 wei;\n}\n"},"BMath.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BNum.sol\";\n\ncontract BMath is BBronze, BConst, BNum {\n    /**********************************************************************************************\n    // calcSpotPrice                                                                             //\n    // sP = spotPrice                                                                            //\n    // bI = tokenBalanceIn                ( bI / wI )         1                                  //\n    // bO = tokenBalanceOut         sP =  -----------  *  ----------                             //\n    // wI = tokenWeightIn                 ( bO / wO )     ( 1 - sF )                             //\n    // wO = tokenWeightOut                                                                       //\n    // sF = swapFee                                                                              //\n    **********************************************************************************************/\n    function calcSpotPrice(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint swapFee\n    )\n        public pure\n        returns (uint spotPrice)\n    {\n        uint numer = bdiv(tokenBalanceIn, tokenWeightIn);\n        uint denom = bdiv(tokenBalanceOut, tokenWeightOut);\n        uint ratio = bdiv(numer, denom);\n        uint scale = bdiv(BONE, bsub(BONE, swapFee));\n        return  (spotPrice = bmul(ratio, scale));\n    }\n\n    /**********************************************************************************************\n    // calcOutGivenIn                                                                            //\n    // aO = tokenAmountOut                                                                       //\n    // bO = tokenBalanceOut                                                                      //\n    // bI = tokenBalanceIn              /      /            bI             \\    (wI / wO) \\      //\n    // aI = tokenAmountIn    aO = bO * |  1 - | --------------------------  | ^            |     //\n    // wI = tokenWeightIn               \\      \\ ( bI + ( aI * ( 1 - sF )) /              /      //\n    // wO = tokenWeightOut                                                                       //\n    // sF = swapFee                                                                              //\n    **********************************************************************************************/\n    function calcOutGivenIn(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint tokenAmountIn,\n        uint swapFee\n    )\n        public pure\n        returns (uint tokenAmountOut)\n    {\n        uint weightRatio = bdiv(tokenWeightIn, tokenWeightOut);\n        uint adjustedIn = bsub(BONE, swapFee);\n        adjustedIn = bmul(tokenAmountIn, adjustedIn);\n        uint y = bdiv(tokenBalanceIn, badd(tokenBalanceIn, adjustedIn));\n        uint foo = bpow(y, weightRatio);\n        uint bar = bsub(BONE, foo);\n        tokenAmountOut = bmul(tokenBalanceOut, bar);\n        return tokenAmountOut;\n    }\n\n    /**********************************************************************************************\n    // calcInGivenOut                                                                            //\n    // aI = tokenAmountIn                                                                        //\n    // bO = tokenBalanceOut               /  /     bO      \\    (wO / wI)      \\                 //\n    // bI = tokenBalanceIn          bI * |  | ------------  | ^            - 1  |                //\n    // aO = tokenAmountOut    aI =        \\  \\ ( bO - aO ) /                   /                 //\n    // wI = tokenWeightIn           --------------------------------------------                 //\n    // wO = tokenWeightOut                          ( 1 - sF )                                   //\n    // sF = swapFee                                                                              //\n    **********************************************************************************************/\n    function calcInGivenOut(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint tokenAmountOut,\n        uint swapFee\n    )\n        public pure\n        returns (uint tokenAmountIn)\n    {\n        uint weightRatio = bdiv(tokenWeightOut, tokenWeightIn);\n        uint diff = bsub(tokenBalanceOut, tokenAmountOut);\n        uint y = bdiv(tokenBalanceOut, diff);\n        uint foo = bpow(y, weightRatio);\n        foo = bsub(foo, BONE);\n        tokenAmountIn = bsub(BONE, swapFee);\n        tokenAmountIn = bdiv(bmul(tokenBalanceIn, foo), tokenAmountIn);\n        return tokenAmountIn;\n    }\n\n    /**********************************************************************************************\n    // calcPoolOutGivenSingleIn                                                                  //\n    // pAo = poolAmountOut         /                                              \\              //\n    // tAi = tokenAmountIn        ///      /     //    wI \\      \\\\       \\     wI \\             //\n    // wI = tokenWeightIn        //| tAi *| 1 - || 1 - --  | * sF || + tBi \\    --  \\            //\n    // tW = totalWeight     pAo=||  \\      \\     \\\\    tW /      //         | ^ tW   | * pS - pS //\n    // tBi = tokenBalanceIn      \\\\  ------------------------------------- /        /            //\n    // pS = poolSupply            \\\\                    tBi               /        /             //\n    // sF = swapFee                \\                                              /              //\n    **********************************************************************************************/\n    function calcPoolOutGivenSingleIn(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint poolSupply,\n        uint totalWeight,\n        uint tokenAmountIn,\n        uint swapFee\n    )\n        public pure\n        returns (uint poolAmountOut)\n    {\n        // Charge the trading fee for the proportion of tokenAi\n        ///  which is implicitly traded to the other pool tokens.\n        // That proportion is (1- weightTokenIn)\n        // tokenAiAfterFee = tAi * (1 - (1-weightTi) * poolFee);\n        uint normalizedWeight = bdiv(tokenWeightIn, totalWeight);\n        uint zaz = bmul(bsub(BONE, normalizedWeight), swapFee); \n        uint tokenAmountInAfterFee = bmul(tokenAmountIn, bsub(BONE, zaz));\n\n        uint newTokenBalanceIn = badd(tokenBalanceIn, tokenAmountInAfterFee);\n        uint tokenInRatio = bdiv(newTokenBalanceIn, tokenBalanceIn);\n\n        // uint newPoolSupply = (ratioTi ^ weightTi) * poolSupply;\n        uint poolRatio = bpow(tokenInRatio, normalizedWeight);\n        uint newPoolSupply = bmul(poolRatio, poolSupply);\n        poolAmountOut = bsub(newPoolSupply, poolSupply);\n        return poolAmountOut;\n    }\n\n    /**********************************************************************************************\n    // calcSingleInGivenPoolOut                                                                  //\n    // tAi = tokenAmountIn              //(pS + pAo)\\     /    1    \\\\                           //\n    // pS = poolSupply                 || ---------  | ^ | --------- || * bI - bI                //\n    // pAo = poolAmountOut              \\\\    pS    /     \\(wI / tW)//                           //\n    // bI = balanceIn          tAi =  --------------------------------------------               //\n    // wI = weightIn                              /      wI  \\                                   //\n    // tW = totalWeight                          |  1 - ----  |  * sF                            //\n    // sF = swapFee                               \\      tW  /                                   //\n    **********************************************************************************************/\n    function calcSingleInGivenPoolOut(\n        uint tokenBalanceIn,\n        uint tokenWeightIn,\n        uint poolSupply,\n        uint totalWeight,\n        uint poolAmountOut,\n        uint swapFee\n    )\n        public pure\n        returns (uint tokenAmountIn)\n    {\n        uint normalizedWeight = bdiv(tokenWeightIn, totalWeight);\n        uint newPoolSupply = badd(poolSupply, poolAmountOut);\n        uint poolRatio = bdiv(newPoolSupply, poolSupply);\n      \n        //uint newBalTi = poolRatio^(1/weightTi) * balTi;\n        uint boo = bdiv(BONE, normalizedWeight); \n        uint tokenInRatio = bpow(poolRatio, boo);\n        uint newTokenBalanceIn = bmul(tokenInRatio, tokenBalanceIn);\n        uint tokenAmountInAfterFee = bsub(newTokenBalanceIn, tokenBalanceIn);\n        // Do reverse order of fees charged in joinswap_ExternAmountIn, this way \n        //     ``` pAo == joinswap_ExternAmountIn(Ti, joinswap_PoolAmountOut(pAo, Ti)) ```\n        //uint tAi = tAiAfterFee / (1 - (1-weightTi) * swapFee) ;\n        uint zar = bmul(bsub(BONE, normalizedWeight), swapFee);\n        tokenAmountIn = bdiv(tokenAmountInAfterFee, bsub(BONE, zar));\n        return tokenAmountIn;\n    }\n\n    /**********************************************************************************************\n    // calcSingleOutGivenPoolIn                                                                  //\n    // tAo = tokenAmountOut            /      /                                             \\\\   //\n    // bO = tokenBalanceOut           /      // pS - (pAi * (1 - eF)) \\     /    1    \\      \\\\  //\n    // pAi = poolAmountIn            | bO - || ----------------------- | ^ | --------- | * b0 || //\n    // ps = poolSupply                \\      \\\\          pS           /     \\(wO / tW)/      //  //\n    // wI = tokenWeightIn      tAo =   \\      \\                                             //   //\n    // tW = totalWeight                    /     /      wO \\       \\                             //\n    // sF = swapFee                    *  | 1 - |  1 - ---- | * sF  |                            //\n    // eF = exitFee                        \\     \\      tW /       /                             //\n    **********************************************************************************************/\n    function calcSingleOutGivenPoolIn(\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint poolSupply,\n        uint totalWeight,\n        uint poolAmountIn,\n        uint swapFee\n    )\n        public pure\n        returns (uint tokenAmountOut)\n    {\n        uint normalizedWeight = bdiv(tokenWeightOut, totalWeight);\n        // charge exit fee on the pool token side\n        // pAiAfterExitFee = pAi*(1-exitFee)\n        uint poolAmountInAfterExitFee = bmul(poolAmountIn, bsub(BONE, EXIT_FEE));\n        uint newPoolSupply = bsub(poolSupply, poolAmountInAfterExitFee);\n        uint poolRatio = bdiv(newPoolSupply, poolSupply);\n     \n        // newBalTo = poolRatio^(1/weightTo) * balTo;\n        uint tokenOutRatio = bpow(poolRatio, bdiv(BONE, normalizedWeight));\n        uint newTokenBalanceOut = bmul(tokenOutRatio, tokenBalanceOut);\n\n        uint tokenAmountOutBeforeSwapFee = bsub(tokenBalanceOut, newTokenBalanceOut);\n\n        // charge swap fee on the output token side \n        //uint tAo = tAoBeforeSwapFee * (1 - (1-weightTo) * swapFee)\n        uint zaz = bmul(bsub(BONE, normalizedWeight), swapFee); \n        tokenAmountOut = bmul(tokenAmountOutBeforeSwapFee, bsub(BONE, zaz));\n        return tokenAmountOut;\n    }\n\n    /**********************************************************************************************\n    // calcPoolInGivenSingleOut                                                                  //\n    // pAi = poolAmountIn               // /               tAo             \\\\     / wO \\     \\   //\n    // bO = tokenBalanceOut            // | bO - -------------------------- |\\   | ---- |     \\  //\n    // tAo = tokenAmountOut      pS - ||   \\     1 - ((1 - (tO / tW)) * sF)/  | ^ \\ tW /  * pS | //\n    // ps = poolSupply                 \\\\ -----------------------------------/                /  //\n    // wO = tokenWeightOut  pAi =       \\\\               bO                 /                /   //\n    // tW = totalWeight           -------------------------------------------------------------  //\n    // sF = swapFee                                        ( 1 - eF )                            //\n    // eF = exitFee                                                                              //\n    **********************************************************************************************/\n    function calcPoolInGivenSingleOut(\n        uint tokenBalanceOut,\n        uint tokenWeightOut,\n        uint poolSupply,\n        uint totalWeight,\n        uint tokenAmountOut,\n        uint swapFee\n    )\n        public pure\n        returns (uint poolAmountIn)\n    {\n\n        // charge swap fee on the output token side \n        uint normalizedWeight = bdiv(tokenWeightOut, totalWeight);\n        //uint tAoBeforeSwapFee = tAo / (1 - (1-weightTo) * swapFee) ;\n        uint zoo = bsub(BONE, normalizedWeight);\n        uint zar = bmul(zoo, swapFee); \n        uint tokenAmountOutBeforeSwapFee = bdiv(tokenAmountOut, bsub(BONE, zar));\n\n        uint newTokenBalanceOut = bsub(tokenBalanceOut, tokenAmountOutBeforeSwapFee);\n        uint tokenOutRatio = bdiv(newTokenBalanceOut, tokenBalanceOut);\n\n        //uint newPoolSupply = (ratioTo ^ weightTo) * poolSupply;\n        uint poolRatio = bpow(tokenOutRatio, normalizedWeight);\n        uint newPoolSupply = bmul(poolRatio, poolSupply);\n        uint poolAmountInAfterExitFee = bsub(poolSupply, newPoolSupply);\n\n        // charge exit fee on the pool token side\n        // pAi = pAiAfterExitFee/(1-exitFee)\n        poolAmountIn = bdiv(poolAmountInAfterExitFee, bsub(BONE, EXIT_FEE));\n        return poolAmountIn;\n    }\n\n\n}\n"},"BNum.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BConst.sol\";\n\ncontract BNum is BConst {\n\n    function btoi(uint a)\n        internal pure \n        returns (uint)\n    {\n        return a / BONE;\n    }\n\n    function bfloor(uint a)\n        internal pure\n        returns (uint)\n    {\n        return btoi(a) * BONE;\n    }\n\n    function badd(uint a, uint b)\n        internal pure\n        returns (uint)\n    {\n        uint c = a + b;\n        require(c \u003e= a, \"ERR_ADD_OVERFLOW\");\n        return c;\n    }\n\n    function bsub(uint a, uint b)\n        internal pure\n        returns (uint)\n    {\n        (uint c, bool flag) = bsubSign(a, b);\n        require(!flag, \"ERR_SUB_UNDERFLOW\");\n        return c;\n    }\n\n    function bsubSign(uint a, uint b)\n        internal pure\n        returns (uint, bool)\n    {\n        if (a \u003e= b) {\n            return (a - b, false);\n        } else {\n            return (b - a, true);\n        }\n    }\n\n    function bmul(uint a, uint b)\n        internal pure\n        returns (uint)\n    {\n        uint c0 = a * b;\n        require(a == 0 || c0 / a == b, \"ERR_MUL_OVERFLOW\");\n        uint c1 = c0 + (BONE / 2);\n        require(c1 \u003e= c0, \"ERR_MUL_OVERFLOW\");\n        uint c2 = c1 / BONE;\n        return c2;\n    }\n\n    function bdiv(uint a, uint b)\n        internal pure\n        returns (uint)\n    {\n        require(b != 0, \"ERR_DIV_ZERO\");\n        uint c0 = a * BONE;\n        require(a == 0 || c0 / a == BONE, \"ERR_DIV_INTERNAL\"); // bmul overflow\n        uint c1 = c0 + (b / 2);\n        require(c1 \u003e= c0, \"ERR_DIV_INTERNAL\"); //  badd require\n        uint c2 = c1 / b;\n        return c2;\n    }\n\n    // DSMath.wpow\n    function bpowi(uint a, uint n)\n        internal pure\n        returns (uint)\n    {\n        uint z = n % 2 != 0 ? a : BONE;\n\n        for (n /= 2; n != 0; n /= 2) {\n            a = bmul(a, a);\n\n            if (n % 2 != 0) {\n                z = bmul(z, a);\n            }\n        }\n        return z;\n    }\n\n    // Compute b^(e.w) by splitting it into (b^e)*(b^0.w).\n    // Use `bpowi` for `b^e` and `bpowK` for k iterations\n    // of approximation of b^0.w\n    function bpow(uint base, uint exp)\n        internal pure\n        returns (uint)\n    {\n        require(base \u003e= MIN_BPOW_BASE, \"ERR_BPOW_BASE_TOO_LOW\");\n        require(base \u003c= MAX_BPOW_BASE, \"ERR_BPOW_BASE_TOO_HIGH\");\n\n        uint whole  = bfloor(exp);   \n        uint remain = bsub(exp, whole);\n\n        uint wholePow = bpowi(base, btoi(whole));\n\n        if (remain == 0) {\n            return wholePow;\n        }\n\n        uint partialResult = bpowApprox(base, remain, BPOW_PRECISION);\n        return bmul(wholePow, partialResult);\n    }\n\n    function bpowApprox(uint base, uint exp, uint precision)\n        internal pure\n        returns (uint)\n    {\n        // term 0:\n        uint a     = exp;\n        (uint x, bool xneg)  = bsubSign(base, BONE);\n        uint term = BONE;\n        uint sum   = term;\n        bool negative = false;\n\n\n        // term(k) = numer / denom \n        //         = (product(a - i - 1, i=1--\u003ek) * x^k) / (k!)\n        // each iteration, multiply previous term by (a-(k-1)) * x / k\n        // continue until term is less than precision\n        for (uint i = 1; term \u003e= precision; i++) {\n            uint bigK = i * BONE;\n            (uint c, bool cneg) = bsubSign(a, bsub(bigK, BONE));\n            term = bmul(term, bmul(c, x));\n            term = bdiv(term, bigK);\n            if (term == 0) break;\n\n            if (xneg) negative = !negative;\n            if (cneg) negative = !negative;\n            if (negative) {\n                sum = bsub(sum, term);\n            } else {\n                sum = badd(sum, term);\n            }\n        }\n\n        return sum;\n    }\n\n}\n"},"BPool.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BToken.sol\";\nimport \"./BMath.sol\";\n\ncontract BPool is BBronze, BToken, BMath {\n\n    struct Record {\n        bool bound;   // is token bound to pool\n        uint index;   // private\n        uint denorm;  // denormalized weight\n        uint balance;\n    }\n\n    event LOG_SWAP(\n        address indexed caller,\n        address indexed tokenIn,\n        address indexed tokenOut,\n        uint256         tokenAmountIn,\n        uint256         tokenAmountOut\n    );\n\n    event LOG_JOIN(\n        address indexed caller,\n        address indexed tokenIn,\n        uint256         tokenAmountIn\n    );\n\n    event LOG_EXIT(\n        address indexed caller,\n        address indexed tokenOut,\n        uint256         tokenAmountOut\n    );\n\n    event LOG_CALL(\n        bytes4  indexed sig,\n        address indexed caller,\n        bytes           data\n    ) anonymous;\n\n    modifier _logs_() {\n        emit LOG_CALL(msg.sig, msg.sender, msg.data);\n        _;\n    }\n\n    modifier _lock_() {\n        require(!_mutex, \"ERR_REENTRY\");\n        _mutex = true;\n        _;\n        _mutex = false;\n    }\n\n    modifier _viewlock_() {\n        require(!_mutex, \"ERR_REENTRY\");\n        _;\n    }\n\n    bool private _mutex;\n\n    address private _factory;    // BFactory address to push token exitFee to\n    address private _controller; // has CONTROL role\n    bool private _publicSwap; // true if PUBLIC can call SWAP functions\n\n    // `setSwapFee` and `finalize` require CONTROL\n    // `finalize` sets `PUBLIC can SWAP`, `PUBLIC can JOIN`\n    uint private _swapFee;\n    bool private _finalized;\n\n    address[] private _tokens;\n    mapping(address=\u003eRecord) private  _records;\n    uint private _totalWeight;\n\n    constructor() public {\n        _controller = msg.sender;\n        _factory = msg.sender;\n        _swapFee = MIN_FEE;\n        _publicSwap = false;\n        _finalized = false;\n    }\n\n    function isPublicSwap()\n        external view\n        returns (bool)\n    {\n        return _publicSwap;\n    }\n\n    function isFinalized()\n        external view\n        returns (bool)\n    {\n        return _finalized;\n    }\n\n    function isBound(address t)\n        external view\n        returns (bool)\n    {\n        return _records[t].bound;\n    }\n\n    function getNumTokens()\n        external view\n        returns (uint) \n    {\n        return _tokens.length;\n    }\n\n    function getCurrentTokens()\n        external view _viewlock_\n        returns (address[] memory tokens)\n    {\n        return _tokens;\n    }\n\n    function getFinalTokens()\n        external view\n        _viewlock_\n        returns (address[] memory tokens)\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        return _tokens;\n    }\n\n    function getDenormalizedWeight(address token)\n        external view\n        _viewlock_\n        returns (uint)\n    {\n\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        return _records[token].denorm;\n    }\n\n    function getTotalDenormalizedWeight()\n        external view\n        _viewlock_\n        returns (uint)\n    {\n        return _totalWeight;\n    }\n\n    function getNormalizedWeight(address token)\n        external view\n        _viewlock_\n        returns (uint)\n    {\n\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        uint denorm = _records[token].denorm;\n        return bdiv(denorm, _totalWeight);\n    }\n\n    function getBalance(address token)\n        external view\n        _viewlock_\n        returns (uint)\n    {\n\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        return _records[token].balance;\n    }\n\n    function getSwapFee()\n        external view\n        _viewlock_\n        returns (uint)\n    {\n        return _swapFee;\n    }\n\n    function getController()\n        external view\n        _viewlock_\n        returns (address)\n    {\n        return _controller;\n    }\n\n    function setSwapFee(uint swapFee)\n        external\n        _logs_\n        _lock_\n    { \n        require(!_finalized, \"ERR_IS_FINALIZED\");\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(swapFee \u003e= MIN_FEE, \"ERR_MIN_FEE\");\n        require(swapFee \u003c= MAX_FEE, \"ERR_MAX_FEE\");\n        _swapFee = swapFee;\n    }\n\n    function setController(address manager)\n        external\n        _logs_\n        _lock_\n    {\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        _controller = manager;\n    }\n\n    function setPublicSwap(bool public_)\n        external\n        _logs_\n        _lock_\n    {\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        _publicSwap = public_;\n    }\n\n    function finalize()\n        external\n        _logs_\n        _lock_\n    {\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n        require(_tokens.length \u003e= MIN_BOUND_TOKENS, \"ERR_MIN_TOKENS\");\n\n        _finalized = true;\n        _publicSwap = true;\n\n        _mintPoolShare(INIT_POOL_SUPPLY);\n        _pushPoolShare(msg.sender, INIT_POOL_SUPPLY);\n    }\n\n\n    function bind(address token, uint balance, uint denorm)\n        external\n        _logs_\n        // _lock_  Bind does not lock because it jumps to `rebind`, which does\n    {\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(!_records[token].bound, \"ERR_IS_BOUND\");\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n\n        require(_tokens.length \u003c MAX_BOUND_TOKENS, \"ERR_MAX_TOKENS\");\n\n        _records[token] = Record({\n            bound: true,\n            index: _tokens.length,\n            denorm: 0,    // balance and denorm will be validated\n            balance: 0   // and set by `rebind`\n        });\n        _tokens.push(token);\n        rebind(token, balance, denorm);\n    }\n\n    function rebind(address token, uint balance, uint denorm)\n        public\n        _logs_\n        _lock_\n    {\n\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n\n        require(denorm \u003e= MIN_WEIGHT, \"ERR_MIN_WEIGHT\");\n        require(denorm \u003c= MAX_WEIGHT, \"ERR_MAX_WEIGHT\");\n        require(balance \u003e= MIN_BALANCE, \"ERR_MIN_BALANCE\");\n\n        // Adjust the denorm and totalWeight\n        uint oldWeight = _records[token].denorm;\n        if (denorm \u003e oldWeight) {\n            _totalWeight = badd(_totalWeight, bsub(denorm, oldWeight));\n            require(_totalWeight \u003c= MAX_TOTAL_WEIGHT, \"ERR_MAX_TOTAL_WEIGHT\");\n        } else if (denorm \u003c oldWeight) {\n            _totalWeight = bsub(_totalWeight, bsub(oldWeight, denorm));\n        }        \n        _records[token].denorm = denorm;\n\n        // Adjust the balance record and actual token balance\n        uint oldBalance = _records[token].balance;\n        _records[token].balance = balance;\n        if (balance \u003e oldBalance) {\n            _pullUnderlying(token, msg.sender, bsub(balance, oldBalance));\n        } else if (balance \u003c oldBalance) {\n            // In this case liquidity is being withdrawn, so charge EXIT_FEE\n            uint tokenBalanceWithdrawn = bsub(oldBalance, balance);\n            uint tokenExitFee = bmul(tokenBalanceWithdrawn, EXIT_FEE);\n            _pushUnderlying(token, msg.sender, bsub(tokenBalanceWithdrawn, tokenExitFee));\n            _pushUnderlying(token, _factory, tokenExitFee);\n        }\n    }\n\n    function unbind(address token)\n        external\n        _logs_\n        _lock_\n    {\n\n        require(msg.sender == _controller, \"ERR_NOT_CONTROLLER\");\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        require(!_finalized, \"ERR_IS_FINALIZED\");\n\n        uint tokenBalance = _records[token].balance;\n        uint tokenExitFee = bmul(tokenBalance, EXIT_FEE);\n\n        _totalWeight = bsub(_totalWeight, _records[token].denorm);\n\n        // Swap the token-to-unbind with the last token,\n        // then delete the last token\n        uint index = _records[token].index;\n        uint last = _tokens.length - 1;\n        _tokens[index] = _tokens[last];\n        _records[_tokens[index]].index = index;\n        _tokens.pop();\n        _records[token] = Record({\n            bound: false,\n            index: 0,\n            denorm: 0,\n            balance: 0\n        });\n\n        _pushUnderlying(token, msg.sender, bsub(tokenBalance, tokenExitFee));\n        _pushUnderlying(token, _factory, tokenExitFee);\n    }\n\n    // Absorb any tokens that have been sent to this contract into the pool\n    function gulp(address token)\n        external\n        _logs_\n        _lock_\n    {\n        require(_records[token].bound, \"ERR_NOT_BOUND\");\n        _records[token].balance = IERC20(token).balanceOf(address(this));\n    }\n\n    function getSpotPrice(address tokenIn, address tokenOut)\n        external view\n        _viewlock_\n        returns (uint spotPrice)\n    {\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        Record storage inRecord = _records[tokenIn];\n        Record storage outRecord = _records[tokenOut];\n        return calcSpotPrice(inRecord.balance, inRecord.denorm, outRecord.balance, outRecord.denorm, _swapFee);\n    }\n\n    function getSpotPriceSansFee(address tokenIn, address tokenOut)\n        external view\n        _viewlock_\n        returns (uint spotPrice)\n    {\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        Record storage inRecord = _records[tokenIn];\n        Record storage outRecord = _records[tokenOut];\n        return calcSpotPrice(inRecord.balance, inRecord.denorm, outRecord.balance, outRecord.denorm, 0);\n    }\n\n    function joinPool(uint poolAmountOut, uint[] calldata maxAmountsIn)\n        external\n        _logs_\n        _lock_\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n\n        uint poolTotal = totalSupply();\n        uint ratio = bdiv(poolAmountOut, poolTotal);\n        require(ratio != 0, \"ERR_MATH_APPROX\");\n\n        for (uint i = 0; i \u003c _tokens.length; i++) {\n            address t = _tokens[i];\n            uint bal = _records[t].balance;\n            uint tokenAmountIn = bmul(ratio, bal);\n            require(tokenAmountIn != 0, \"ERR_MATH_APPROX\");\n            require(tokenAmountIn \u003c= maxAmountsIn[i], \"ERR_LIMIT_IN\");\n            _records[t].balance = badd(_records[t].balance, tokenAmountIn);\n            emit LOG_JOIN(msg.sender, t, tokenAmountIn);\n            _pullUnderlying(t, msg.sender, tokenAmountIn);\n        }\n        _mintPoolShare(poolAmountOut);\n        _pushPoolShare(msg.sender, poolAmountOut);\n    }\n\n    function exitPool(uint poolAmountIn, uint[] calldata minAmountsOut)\n        external\n        _logs_\n        _lock_\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n\n        uint poolTotal = totalSupply();\n        uint exitFee = bmul(poolAmountIn, EXIT_FEE);\n        uint pAiAfterExitFee = bsub(poolAmountIn, exitFee);\n        uint ratio = bdiv(pAiAfterExitFee, poolTotal);\n        require(ratio != 0, \"ERR_MATH_APPROX\");\n\n        _pullPoolShare(msg.sender, poolAmountIn);\n        _pushPoolShare(_factory, exitFee);\n        _burnPoolShare(pAiAfterExitFee);\n\n        for (uint i = 0; i \u003c _tokens.length; i++) {\n            address t = _tokens[i];\n            uint bal = _records[t].balance;\n            uint tokenAmountOut = bmul(ratio, bal);\n            require(tokenAmountOut != 0, \"ERR_MATH_APPROX\");\n            require(tokenAmountOut \u003e= minAmountsOut[i], \"ERR_LIMIT_OUT\");\n            _records[t].balance = bsub(_records[t].balance, tokenAmountOut);\n            emit LOG_EXIT(msg.sender, t, tokenAmountOut);\n            _pushUnderlying(t, msg.sender, tokenAmountOut);\n        }\n\n    }\n\n\n    function swapExactAmountIn(\n        address tokenIn,\n        uint tokenAmountIn,\n        address tokenOut,\n        uint minAmountOut,\n        uint maxPrice\n    )\n        external\n        _logs_\n        _lock_\n        returns (uint tokenAmountOut, uint spotPriceAfter)\n    {\n\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        require(_publicSwap, \"ERR_SWAP_NOT_PUBLIC\");\n\n        Record storage inRecord = _records[address(tokenIn)];\n        Record storage outRecord = _records[address(tokenOut)];\n\n        require(tokenAmountIn \u003c= bmul(inRecord.balance, MAX_IN_RATIO), \"ERR_MAX_IN_RATIO\");\n\n        uint spotPriceBefore = calcSpotPrice(\n                                    inRecord.balance,\n                                    inRecord.denorm,\n                                    outRecord.balance,\n                                    outRecord.denorm,\n                                    _swapFee\n                                );\n        require(spotPriceBefore \u003c= maxPrice, \"ERR_BAD_LIMIT_PRICE\");\n\n        tokenAmountOut = calcOutGivenIn(\n                            inRecord.balance,\n                            inRecord.denorm,\n                            outRecord.balance,\n                            outRecord.denorm,\n                            tokenAmountIn,\n                            _swapFee\n                        );\n        require(tokenAmountOut \u003e= minAmountOut, \"ERR_LIMIT_OUT\");\n\n        inRecord.balance = badd(inRecord.balance, tokenAmountIn);\n        outRecord.balance = bsub(outRecord.balance, tokenAmountOut);\n\n        spotPriceAfter = calcSpotPrice(\n                                inRecord.balance,\n                                inRecord.denorm,\n                                outRecord.balance,\n                                outRecord.denorm,\n                                _swapFee\n                            );\n        require(spotPriceAfter \u003e= spotPriceBefore, \"ERR_MATH_APPROX\");     \n        require(spotPriceAfter \u003c= maxPrice, \"ERR_LIMIT_PRICE\");\n        require(spotPriceBefore \u003c= bdiv(tokenAmountIn, tokenAmountOut), \"ERR_MATH_APPROX\");\n\n        emit LOG_SWAP(msg.sender, tokenIn, tokenOut, tokenAmountIn, tokenAmountOut);\n\n        _pullUnderlying(tokenIn, msg.sender, tokenAmountIn);\n        _pushUnderlying(tokenOut, msg.sender, tokenAmountOut);\n\n        return (tokenAmountOut, spotPriceAfter);\n    }\n\n    function swapExactAmountOut(\n        address tokenIn,\n        uint maxAmountIn,\n        address tokenOut,\n        uint tokenAmountOut,\n        uint maxPrice\n    )\n        external\n        _logs_\n        _lock_ \n        returns (uint tokenAmountIn, uint spotPriceAfter)\n    {\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        require(_publicSwap, \"ERR_SWAP_NOT_PUBLIC\");\n\n        Record storage inRecord = _records[address(tokenIn)];\n        Record storage outRecord = _records[address(tokenOut)];\n\n        require(tokenAmountOut \u003c= bmul(outRecord.balance, MAX_OUT_RATIO), \"ERR_MAX_OUT_RATIO\");\n\n        uint spotPriceBefore = calcSpotPrice(\n                                    inRecord.balance,\n                                    inRecord.denorm,\n                                    outRecord.balance,\n                                    outRecord.denorm,\n                                    _swapFee\n                                );\n        require(spotPriceBefore \u003c= maxPrice, \"ERR_BAD_LIMIT_PRICE\");\n\n        tokenAmountIn = calcInGivenOut(\n                            inRecord.balance,\n                            inRecord.denorm,\n                            outRecord.balance,\n                            outRecord.denorm,\n                            tokenAmountOut,\n                            _swapFee\n                        );\n        require(tokenAmountIn \u003c= maxAmountIn, \"ERR_LIMIT_IN\");\n\n        inRecord.balance = badd(inRecord.balance, tokenAmountIn);\n        outRecord.balance = bsub(outRecord.balance, tokenAmountOut);\n\n        spotPriceAfter = calcSpotPrice(\n                                inRecord.balance,\n                                inRecord.denorm,\n                                outRecord.balance,\n                                outRecord.denorm,\n                                _swapFee\n                            );\n        require(spotPriceAfter \u003e= spotPriceBefore, \"ERR_MATH_APPROX\");\n        require(spotPriceAfter \u003c= maxPrice, \"ERR_LIMIT_PRICE\");\n        require(spotPriceBefore \u003c= bdiv(tokenAmountIn, tokenAmountOut), \"ERR_MATH_APPROX\");\n\n        emit LOG_SWAP(msg.sender, tokenIn, tokenOut, tokenAmountIn, tokenAmountOut);\n\n        _pullUnderlying(tokenIn, msg.sender, tokenAmountIn);\n        _pushUnderlying(tokenOut, msg.sender, tokenAmountOut);\n\n        return (tokenAmountIn, spotPriceAfter);\n    }\n\n\n    function joinswapExternAmountIn(address tokenIn, uint tokenAmountIn, uint minPoolAmountOut)\n        external\n        _logs_\n        _lock_\n        returns (uint poolAmountOut)\n\n    {        \n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n        require(tokenAmountIn \u003c= bmul(_records[tokenIn].balance, MAX_IN_RATIO), \"ERR_MAX_IN_RATIO\");\n\n        Record storage inRecord = _records[tokenIn];\n\n        poolAmountOut = calcPoolOutGivenSingleIn(\n                            inRecord.balance,\n                            inRecord.denorm,\n                            _totalSupply,\n                            _totalWeight,\n                            tokenAmountIn,\n                            _swapFee\n                        );\n\n        require(poolAmountOut \u003e= minPoolAmountOut, \"ERR_LIMIT_OUT\");\n\n        inRecord.balance = badd(inRecord.balance, tokenAmountIn);\n\n        emit LOG_JOIN(msg.sender, tokenIn, tokenAmountIn);\n\n        _mintPoolShare(poolAmountOut);\n        _pushPoolShare(msg.sender, poolAmountOut);\n        _pullUnderlying(tokenIn, msg.sender, tokenAmountIn);\n\n        return poolAmountOut;\n    }\n\n    function joinswapPoolAmountOut(address tokenIn, uint poolAmountOut, uint maxAmountIn)\n        external\n        _logs_\n        _lock_\n        returns (uint tokenAmountIn)\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        require(_records[tokenIn].bound, \"ERR_NOT_BOUND\");\n\n        Record storage inRecord = _records[tokenIn];\n\n        tokenAmountIn = calcSingleInGivenPoolOut(\n                            inRecord.balance,\n                            inRecord.denorm,\n                            _totalSupply,\n                            _totalWeight,\n                            poolAmountOut,\n                            _swapFee\n                        );\n\n        require(tokenAmountIn != 0, \"ERR_MATH_APPROX\");\n        require(tokenAmountIn \u003c= maxAmountIn, \"ERR_LIMIT_IN\");\n        \n        require(tokenAmountIn \u003c= bmul(_records[tokenIn].balance, MAX_IN_RATIO), \"ERR_MAX_IN_RATIO\");\n\n        inRecord.balance = badd(inRecord.balance, tokenAmountIn);\n\n        emit LOG_JOIN(msg.sender, tokenIn, tokenAmountIn);\n\n        _mintPoolShare(poolAmountOut);\n        _pushPoolShare(msg.sender, poolAmountOut);\n        _pullUnderlying(tokenIn, msg.sender, tokenAmountIn);\n\n        return tokenAmountIn;\n    }\n\n    function exitswapPoolAmountIn(address tokenOut, uint poolAmountIn, uint minAmountOut)\n        external\n        _logs_\n        _lock_\n        returns (uint tokenAmountOut)\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n\n        Record storage outRecord = _records[tokenOut];\n\n        tokenAmountOut = calcSingleOutGivenPoolIn(\n                            outRecord.balance,\n                            outRecord.denorm,\n                            _totalSupply,\n                            _totalWeight,\n                            poolAmountIn,\n                            _swapFee\n                        );\n\n        require(tokenAmountOut \u003e= minAmountOut, \"ERR_LIMIT_OUT\");\n        \n        require(tokenAmountOut \u003c= bmul(_records[tokenOut].balance, MAX_OUT_RATIO), \"ERR_MAX_OUT_RATIO\");\n\n        outRecord.balance = bsub(outRecord.balance, tokenAmountOut);\n\n        uint exitFee = bmul(poolAmountIn, EXIT_FEE);\n\n        emit LOG_EXIT(msg.sender, tokenOut, tokenAmountOut);\n\n        _pullPoolShare(msg.sender, poolAmountIn);\n        _burnPoolShare(bsub(poolAmountIn, exitFee));\n        _pushPoolShare(_factory, exitFee);\n        _pushUnderlying(tokenOut, msg.sender, tokenAmountOut);\n\n        return tokenAmountOut;\n    }\n\n    function exitswapExternAmountOut(address tokenOut, uint tokenAmountOut, uint maxPoolAmountIn)\n        external\n        _logs_\n        _lock_\n        returns (uint poolAmountIn)\n    {\n        require(_finalized, \"ERR_NOT_FINALIZED\");\n        require(_records[tokenOut].bound, \"ERR_NOT_BOUND\");\n        require(tokenAmountOut \u003c= bmul(_records[tokenOut].balance, MAX_OUT_RATIO), \"ERR_MAX_OUT_RATIO\");\n\n        Record storage outRecord = _records[tokenOut];\n\n        poolAmountIn = calcPoolInGivenSingleOut(\n                            outRecord.balance,\n                            outRecord.denorm,\n                            _totalSupply,\n                            _totalWeight,\n                            tokenAmountOut,\n                            _swapFee\n                        );\n\n        require(poolAmountIn != 0, \"ERR_MATH_APPROX\");\n        require(poolAmountIn \u003c= maxPoolAmountIn, \"ERR_LIMIT_IN\");\n\n        outRecord.balance = bsub(outRecord.balance, tokenAmountOut);\n\n        uint exitFee = bmul(poolAmountIn, EXIT_FEE);\n\n        emit LOG_EXIT(msg.sender, tokenOut, tokenAmountOut);\n\n        _pullPoolShare(msg.sender, poolAmountIn);\n        _burnPoolShare(bsub(poolAmountIn, exitFee));\n        _pushPoolShare(_factory, exitFee);\n        _pushUnderlying(tokenOut, msg.sender, tokenAmountOut);        \n\n        return poolAmountIn;\n    }\n\n\n    // ==\n    // \u0027Underlying\u0027 token-manipulation functions make external calls but are NOT locked\n    // You must `_lock_` or otherwise ensure reentry-safety\n\n    function _pullUnderlying(address erc20, address from, uint amount)\n        internal\n    {\n        bool xfer = IERC20(erc20).transferFrom(from, address(this), amount);\n        require(xfer, \"ERR_ERC20_FALSE\");\n    }\n\n    function _pushUnderlying(address erc20, address to, uint amount)\n        internal\n    {\n        bool xfer = IERC20(erc20).transfer(to, amount);\n        require(xfer, \"ERR_ERC20_FALSE\");\n    }\n\n    function _pullPoolShare(address from, uint amount)\n        internal\n    {\n        _pull(from, amount);\n    }\n\n    function _pushPoolShare(address to, uint amount)\n        internal\n    {\n        _push(to, amount);\n    }\n\n    function _mintPoolShare(uint amount)\n        internal\n    {\n        _mint(amount);\n    }\n\n    function _burnPoolShare(uint amount)\n        internal\n    {\n        _burn(amount);\n    }\n\n}\n"},"BToken.sol":{"content":"// This program is free software: you can redistribute it and/or modify\n// it under the terms of the GNU General Public License as published by\n// the Free Software Foundation, either version 3 of the License, or\n// (at your option) any later version.\n\n// This program is distributed in the hope that it will be useful,\n// but WITHOUT ANY WARRANTY; without even the implied warranty of\n// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n// GNU General Public License for more details.\n\n// You should have received a copy of the GNU General Public License\n// along with this program.  If not, see \u003chttp://www.gnu.org/licenses/\u003e.\n\npragma solidity 0.5.12;\n\nimport \"./BNum.sol\";\n\n// Highly opinionated token implementation\n\ninterface IERC20 {\n    event Approval(address indexed src, address indexed dst, uint amt);\n    event Transfer(address indexed src, address indexed dst, uint amt);\n\n    function totalSupply() external view returns (uint);\n    function balanceOf(address whom) external view returns (uint);\n    function allowance(address src, address dst) external view returns (uint);\n\n    function approve(address dst, uint amt) external returns (bool);\n    function transfer(address dst, uint amt) external returns (bool);\n    function transferFrom(\n        address src, address dst, uint amt\n    ) external returns (bool);\n}\n\ncontract BTokenBase is BNum {\n\n    mapping(address =\u003e uint)                   internal _balance;\n    mapping(address =\u003e mapping(address=\u003euint)) internal _allowance;\n    uint internal _totalSupply;\n\n    event Approval(address indexed src, address indexed dst, uint amt);\n    event Transfer(address indexed src, address indexed dst, uint amt);\n\n    function _mint(uint amt) internal {\n        _balance[address(this)] = badd(_balance[address(this)], amt);\n        _totalSupply = badd(_totalSupply, amt);\n        emit Transfer(address(0), address(this), amt);\n    }\n\n    function _burn(uint amt) internal {\n        require(_balance[address(this)] \u003e= amt, \"ERR_INSUFFICIENT_BAL\");\n        _balance[address(this)] = bsub(_balance[address(this)], amt);\n        _totalSupply = bsub(_totalSupply, amt);\n        emit Transfer(address(this), address(0), amt);\n    }\n\n    function _move(address src, address dst, uint amt) internal {\n        require(_balance[src] \u003e= amt, \"ERR_INSUFFICIENT_BAL\");\n        _balance[src] = bsub(_balance[src], amt);\n        _balance[dst] = badd(_balance[dst], amt);\n        emit Transfer(src, dst, amt);\n    }\n\n    function _push(address to, uint amt) internal {\n        _move(address(this), to, amt);\n    }\n\n    function _pull(address from, uint amt) internal {\n        _move(from, address(this), amt);\n    }\n}\n\ncontract BToken is BTokenBase, IERC20 {\n\n    string  private _name     = \"Balancer Pool Token\";\n    string  private _symbol   = \"BPT\";\n    uint8   private _decimals = 18;\n\n    function name() public view returns (string memory) {\n        return _name;\n    }\n\n    function symbol() public view returns (string memory) {\n        return _symbol;\n    }\n\n    function decimals() public view returns(uint8) {\n        return _decimals;\n    }\n\n    function allowance(address src, address dst) external view returns (uint) {\n        return _allowance[src][dst];\n    }\n\n    function balanceOf(address whom) external view returns (uint) {\n        return _balance[whom];\n    }\n\n    function totalSupply() public view returns (uint) {\n        return _totalSupply;\n    }\n\n    function approve(address dst, uint amt) external returns (bool) {\n        _allowance[msg.sender][dst] = amt;\n        emit Approval(msg.sender, dst, amt);\n        return true;\n    }\n\n    function increaseApproval(address dst, uint amt) external returns (bool) {\n        _allowance[msg.sender][dst] = badd(_allowance[msg.sender][dst], amt);\n        emit Approval(msg.sender, dst, _allowance[msg.sender][dst]);\n        return true;\n    }\n\n    function decreaseApproval(address dst, uint amt) external returns (bool) {\n        uint oldValue = _allowance[msg.sender][dst];\n        if (amt \u003e oldValue) {\n            _allowance[msg.sender][dst] = 0;\n        } else {\n            _allowance[msg.sender][dst] = bsub(oldValue, amt);\n        }\n        emit Approval(msg.sender, dst, _allowance[msg.sender][dst]);\n        return true;\n    }\n\n    function transfer(address dst, uint amt) external returns (bool) {\n        _move(msg.sender, dst, amt);\n        return true;\n    }\n\n    function transferFrom(address src, address dst, uint amt) external returns (bool) {\n        require(msg.sender == src || amt \u003c= _allowance[src][msg.sender], \"ERR_BTOKEN_BAD_CALLER\");\n        _move(src, dst, amt);\n        if (msg.sender != src \u0026\u0026 _allowance[src][msg.sender] != uint256(-1)) {\n            _allowance[src][msg.sender] = bsub(_allowance[src][msg.sender], amt);\n            emit Approval(msg.sender, dst, _allowance[src][msg.sender]);\n        }\n        return true;\n    }\n}\n"}}

// 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
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                     END OF TERMS AND CONDITIONS

            How to Apply These Terms to Your New Programs

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possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
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    <one line to give the program's name and a brief idea of what it does.>
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Also add information on how to contact you by electronic and paper mail.

  If the program does terminal interaction, make it output a short
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    <program>  Copyright (C) <year>  <name of author>
    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
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    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
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  You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.

  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.

*/

/*
                                        ,▄m    ,▄▄▄▄▄▄▄▄▄▄╖
                                    ╓▄▓██▌╓▄▓███████████▀└
                                  ▄████████████▓╬▓███████████▓▓▓▄▄▄,
              ╓,              ,▄▄███▓╣██████▓╬╬▓████████████▀▓████████▓▄,
               ▀█▓▄╥       xΘ╙╠╠███▓╬▓█████╬╬╬▓██████▓╬╬╬▓▀  ▐█╬╬╬╬▓██████▌╖
                 ╙████▓▄Q  ,φ▒▒▒███╬╬█████╬╬╬▓████▓╬╬╬▓▓▀  ╕ ▐█▓▓▓╬╬╬╬╬▓█████▄
                   ╙▓██████▓▄▄▒▒███╬╬╣████╬╬╣███╬╬▓███▀  ▄█⌐ ╫████████▓▓╬╬╬████▌
                   /  ▀███▓████████▓╬╬▓████╬███▓████▀  ▄██▀ ╔██████████████▓▓▓███▄
                 ▄╙     ╙██▓▄╙▀▓█████▓▓▓██████████▀  ª▀▀└ ,▓███████▓╬╬╬▓██████████▌
               ,▓   ╓╠▒≥  ╙▓██▓╖ └▀▓███████▓███▓╙       ▄▓████████████▓╬╬╬╬▓███████▌
              ▄█   ╔▒▒▒▒"   └▀███▌,  ╙████▀         ~Φ▓██▓▀▀╩▓██╙▀██████▓╬╬╬╬▓██████▌
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            ▓█   ╔▒▒▒`    φ▒▒▒ⁿ  ╫██████`         ,▌          ╫██      ╙█████╬╬╬╬██▓
           ╫█─  .▒▒▒     ╠▒▒╚   ]██████¬         ▓█            ██▌       └▓███▓╬╬╬██▓
          ▐█▌   ╠▒▒     φ▒▒"    ▐█████─        ▓█▀██▌          ███       ╬ └████╬╬╬██▌
          ██   ]▒▒⌐    .▒▒       ▓████       ▄█▀┤░▐██        ╓███▀      /╫▒ε ╙███╬╬╣██
         ▐██   ╚▒╚     ╠▒        ║████⌐ ╟▄,▓█▓┤Q▄▓█▀        ▄▀▓▓`      ╓▒▓▌▒╔ └███╬╬██▌
         ▓█▌   ▒▒      ▒╙        ██████ ╫████▓▀▀╙          ▓         ,φ▒║█▌▒▒≥  ███╬▓██
         ██▌   ▒▒      ▒        ▐███╙██b └╙          ▄ÆR▀▀▀       ╓φ╠▒▒▄██▒▒▒▒  ╙███╣██
         ██▌   ▒Γ      ╙        ███▌ ╟█            ,▓,φφ╠▒▒▒▒▒▒▒▒▒▒▒▄▓███▀▒▒▒▒╠  ▓██▓██─
         ██▌   ╚⌐      ⌐       ▓███               ╔▌«▒▒▒▒▄▓████████████▀░▒▒▒▒▒▒  ▐█████
         ███   'ε             ]███⌐             ╓▄▀φ▒▒▒▄▓█████████▓▀╬░▒▒▒▒▒▒▒▒▒   █████
         ╫██µ   φ             ███▌        ╓╔φ╠▒░▓,╠▒▒▒▓███████▀  ╙█▓▄`╙╠▒▒▒▒▒▒▒   █████
         └███                ╫███       ,╠▒▒▄▓▓█▓▓▓▄▄███████▀      ▓██▌,`╚▒▒▒▒▒  ]████▌
          ▓██▌              ▓███¬   ╔  φ▒▒▒╠╠╠╠╬▓████████▓╙         ████▌  ╚▒▒╙  ▓████
           ███▄           ▄███▀  ╒  ╠≥╠▒▒▒░▄▓▌╨╚▒╚▓█████└           ║█████  └▒  ]████`
           └███▌         ▓███╙  ▓▄  ╠▒▒▒▒▒██╙╙▓▓ ▒▒████             ▐██████    ,████╨
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              ████µ      ███b  ▀╙  φ▒▒▒▒▄██▓▓╠φ╠▒▒▓███             ]████████⌐▄████┘
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                ╙████▌    ▓██▓▄,   ▐▓▓██▄▄▄▄▓████▀└              ,█████████████▀
                  ╙████▌µ  ╙▀████████████████▓▀                 ▄████████████▀
                    ╙█████▄,   └╙╙▀▀╙                         ▄████████████▀
                      └▀█████▓▄                            ▄▓███████████▀╙
                         ╙▀██████▓▄▄,                 ,▄▓▓███████████▀╙
                             ╙▀█████████▓▓▓▓▓▓▓▓▓▓▓██████████████▀▀└
                                 ╙╙▀▓███████████████████████▀▀╙
                                        └╙╙╙▀▀▀▀▀▀▀▀▀╙╙└

         ██╗██╗███╗   ██╗ ██████╗██╗  ██╗    ████████╗ ██████╗ ██╗  ██╗███████╗███╗   ██╗
        ███║██║████╗  ██║██╔════╝██║  ██║    ╚══██╔══╝██╔═══██╗██║ ██╔╝██╔════╝████╗  ██║
        ╚██║██║██╔██╗ ██║██║     ███████║       ██║   ██║   ██║█████╔╝ █████╗  ██╔██╗ ██║
         ██║██║██║╚██╗██║██║     ██╔══██║       ██║   ██║   ██║██╔═██╗ ██╔══╝  ██║╚██╗██║
         ██║██║██║ ╚████║╚██████╗██║  ██║       ██║   ╚██████╔╝██║  ██╗███████╗██║ ╚████║
         ╚═╝╚═╝╚═╝  ╚═══╝ ╚═════╝╚═╝  ╚═╝       ╚═╝    ╚═════╝ ╚═╝  ╚═╝╚══════╝╚═╝  ╚═══╝
*/
// File: @openzeppelin/contracts/GSN/Context.sol

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol


pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/math/SafeMath.sol


pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, 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;
    }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol


pragma solidity >=0.6.0 <0.8.0;




/**
 * @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;

    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 { }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20Burnable.sol


pragma solidity >=0.6.0 <0.8.0;



/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20Burnable is Context, ERC20 {
    using SafeMath for uint256;

    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual {
        uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");

        _approve(account, _msgSender(), decreasedAllowance);
        _burn(account, amount);
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol


pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view 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;
    }
}

// File: @openzeppelin/contracts/utils/Counters.sol


pragma solidity >=0.6.0 <0.8.0;


/**
 * @title Counters
 * @author Matt Condon (@shrugs)
 * @dev Provides counters that can only be incremented or decremented by one. This can be used e.g. to track the number
 * of elements in a mapping, issuing ERC721 ids, or counting request ids.
 *
 * Include with `using Counters for Counters.Counter;`
 * Since it is not possible to overflow a 256 bit integer with increments of one, `increment` can skip the {SafeMath}
 * overflow check, thereby saving gas. This does assume however correct usage, in that the underlying `_value` is never
 * directly accessed.
 */
library Counters {
    using SafeMath for uint256;

    struct Counter {
        // This variable should never be directly accessed by users of the library: interactions must be restricted to
        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
        // this feature: see https://github.com/ethereum/solidity/issues/4637
        uint256 _value; // default: 0
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
        // The {SafeMath} overflow check can be skipped here, see the comment at the top
        counter._value += 1;
    }

    function decrement(Counter storage counter) internal {
        counter._value = counter._value.sub(1);
    }
}

// File: contracts/IERC20Permit.sol


pragma solidity ^0.6.0;

// A copy of https://github.com/OpenZeppelin/openzeppelin-contracts/blob/ecc66719bd7681ed4eb8bf406f89a7408569ba9b/contracts/drafts/IERC20Permit.sol

/**
 * @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);
}

// File: contracts/ECDSA.sol


pragma solidity ^0.6.0;

// A copy of https://github.com/OpenZeppelin/openzeppelin-contracts/blob/ecc66719bd7681ed4eb8bf406f89a7408569ba9b/contracts/cryptography/ECDSA.sol

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        // Check the signature length
        if (signature.length != 65) {
            revert("ECDSA: invalid signature length");
        }

        // Divide the signature in r, s and v variables
        bytes32 r;
        bytes32 s;
        uint8 v;

        // ecrecover takes the signature parameters, and the only way to get them
        // currently is to use assembly.
        // solhint-disable-next-line no-inline-assembly
        assembly {
            r := mload(add(signature, 0x20))
            s := mload(add(signature, 0x40))
            v := byte(0, mload(add(signature, 0x60)))
        }

        return recover(hash, v, r, s);
    }

    /**
     * @dev Overload of {ECDSA-recover-bytes32-bytes-} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        require(uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0, "ECDSA: invalid signature s value");
        require(v == 27 || v == 28, "ECDSA: invalid signature v value");

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        require(signer != address(0), "ECDSA: invalid signature");

        return signer;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * replicates the behavior of the
     * https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sign[`eth_sign`]
     * JSON-RPC method.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    }
}

// File: contracts/EIP712.sol


pragma solidity ^0.6.0;

// A copy of https://github.com/OpenZeppelin/openzeppelin-contracts/blob/ecc66719bd7681ed4eb8bf406f89a7408569ba9b/contracts/drafts/EIP712.sol

/**
 * @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
 *
 * The encoding specified in the EIP is very generic, and such a generic implementation in Solidity is not feasible,
 * thus this contract does not implement the encoding itself. Protocols need to implement the type-specific encoding
 * they need in their contracts using a combination of `abi.encode` and `keccak256`.
 *
 * This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
 * scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
 * ({_hashTypedDataV4}).
 *
 * The implementation of the domain separator was designed to be as efficient as possible while still properly updating
 * the chain id to protect against replay attacks on an eventual fork of the chain.
 *
 * NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
 * https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
 */
abstract contract EIP712 {
    /* solhint-disable var-name-mixedcase */
    // Cache the domain separator as an immutable value, but also store the chain id that it corresponds to, in order to
    // invalidate the cached domain separator if the chain id changes.
    bytes32 private immutable _CACHED_DOMAIN_SEPARATOR;
    uint256 private immutable _CACHED_CHAIN_ID;

    bytes32 private immutable _HASHED_NAME;
    bytes32 private immutable _HASHED_VERSION;
    bytes32 private immutable _TYPE_HASH;
    /* solhint-enable var-name-mixedcase */

    /**
     * @dev Initializes the domain separator and parameter caches.
     *
     * The meaning of `name` and `version` is specified in
     * https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
     *
     * - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
     * - `version`: the current major version of the signing domain.
     *
     * NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
     * contract upgrade].
     */
    constructor(string memory name, string memory version) internal {
        bytes32 hashedName = keccak256(bytes(name));
        bytes32 hashedVersion = keccak256(bytes(version));
        bytes32 typeHash = keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
        _HASHED_NAME = hashedName;
        _HASHED_VERSION = hashedVersion;
        _CACHED_CHAIN_ID = _getChainId();
        _CACHED_DOMAIN_SEPARATOR = _buildDomainSeparator(typeHash, hashedName, hashedVersion);
        _TYPE_HASH = typeHash;
    }

    /**
     * @dev Returns the domain separator for the current chain.
     */
    function _domainSeparatorV4() internal view returns (bytes32) {
        if (_getChainId() == _CACHED_CHAIN_ID) {
            return _CACHED_DOMAIN_SEPARATOR;
        } else {
            return _buildDomainSeparator(_TYPE_HASH, _HASHED_NAME, _HASHED_VERSION);
        }
    }

    function _buildDomainSeparator(bytes32 typeHash, bytes32 name, bytes32 version) private view returns (bytes32) {
        return keccak256(
            abi.encode(
                typeHash,
                name,
                version,
                _getChainId(),
                address(this)
            )
        );
    }

    /**
     * @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
     * function returns the hash of the fully encoded EIP712 message for this domain.
     *
     * This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
     *
     * ```solidity
     * bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
     *     keccak256("Mail(address to,string contents)"),
     *     mailTo,
     *     keccak256(bytes(mailContents))
     * )));
     * address signer = ECDSA.recover(digest, signature);
     * ```
     */
    function _hashTypedDataV4(bytes32 structHash) internal view returns (bytes32) {
        return keccak256(abi.encodePacked("\x19\x01", _domainSeparatorV4(), structHash));
    }

    function _getChainId() private pure returns (uint256 chainId) {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            chainId := chainid()
        }
    }
}

// File: contracts/ERC20Permit.sol


pragma solidity ^0.6.0;






// An adapted copy of https://github.com/OpenZeppelin/openzeppelin-contracts/blob/ecc66719bd7681ed4eb8bf406f89a7408569ba9b/contracts/drafts/ERC20Permit.sol

/**
 * @dev Implementation 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.
 */
abstract contract ERC20Permit is ERC20, IERC20Permit, EIP712 {
    using Counters for Counters.Counter;

    mapping (address => Counters.Counter) private _nonces;

    // solhint-disable-next-line var-name-mixedcase
    bytes32 private immutable _PERMIT_TYPEHASH = keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");

    /**
     * @dev See {IERC20Permit-permit}.
     */
    function permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public virtual override {
        // solhint-disable-next-line not-rely-on-time
        require(block.timestamp <= deadline, "ERC20Permit: expired deadline");

        bytes32 structHash = keccak256(
            abi.encode(
                _PERMIT_TYPEHASH,
                owner,
                spender,
                value,
                _nonces[owner].current(),
                deadline
            )
        );

        bytes32 hash = _hashTypedDataV4(structHash);

        address signer = ECDSA.recover(hash, v, r, s);
        require(signer == owner, "ERC20Permit: invalid signature");

        _nonces[owner].increment();
        _approve(owner, spender, value);
    }

    /**
     * @dev See {IERC20Permit-nonces}.
     */
    function nonces(address owner) public view override returns (uint256) {
        return _nonces[owner].current();
    }

    /**
     * @dev See {IERC20Permit-DOMAIN_SEPARATOR}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view override returns (bytes32) {
        return _domainSeparatorV4();
    }
}

// File: contracts/OneInch.sol


pragma solidity ^0.6.0;





contract OneInch is ERC20Permit, ERC20Burnable, Ownable {
    constructor(address _owner) public ERC20("1INCH Token", "1INCH") EIP712("1INCH Token", "1") {
        _mint(_owner, 1.5e9 ether);
        transferOwnership(_owner);
    }

    function mint(address to, uint256 amount) external onlyOwner {
        _mint(to, amount);
    }
}

# @title Uniswap Exchange Interface V1
# @notice Source code found at https://github.com/uniswap
# @notice Use at your own risk

contract Factory():
    def getExchange(token_addr: address) -> address: constant

contract Exchange():
    def getEthToTokenOutputPrice(tokens_bought: uint256) -> uint256(wei): constant
    def ethToTokenTransferInput(min_tokens: uint256, deadline: timestamp, recipient: address) -> uint256: modifying
    def ethToTokenTransferOutput(tokens_bought: uint256, deadline: timestamp, recipient: address) -> uint256(wei): modifying

TokenPurchase: event({buyer: indexed(address), eth_sold: indexed(uint256(wei)), tokens_bought: indexed(uint256)})
EthPurchase: event({buyer: indexed(address), tokens_sold: indexed(uint256), eth_bought: indexed(uint256(wei))})
AddLiquidity: event({provider: indexed(address), eth_amount: indexed(uint256(wei)), token_amount: indexed(uint256)})
RemoveLiquidity: event({provider: indexed(address), eth_amount: indexed(uint256(wei)), token_amount: indexed(uint256)})
Transfer: event({_from: indexed(address), _to: indexed(address), _value: uint256})
Approval: event({_owner: indexed(address), _spender: indexed(address), _value: uint256})

name: public(bytes32)                             # Uniswap V1
symbol: public(bytes32)                           # UNI-V1
decimals: public(uint256)                         # 18
totalSupply: public(uint256)                      # total number of UNI in existence
balances: uint256[address]                        # UNI balance of an address
allowances: (uint256[address])[address]           # UNI allowance of one address on another
token: address(ERC20)                             # address of the ERC20 token traded on this contract
factory: Factory                                  # interface for the factory that created this contract

# @dev This function acts as a contract constructor which is not currently supported in contracts deployed
#      using create_with_code_of(). It is called once by the factory during contract creation.
@public
def setup(token_addr: address):
    assert (self.factory == ZERO_ADDRESS and self.token == ZERO_ADDRESS) and token_addr != ZERO_ADDRESS
    self.factory = msg.sender
    self.token = token_addr
    self.name = 0x556e697377617020563100000000000000000000000000000000000000000000
    self.symbol = 0x554e492d56310000000000000000000000000000000000000000000000000000
    self.decimals = 18

# @notice Deposit ETH and Tokens (self.token) at current ratio to mint UNI tokens.
# @dev min_liquidity does nothing when total UNI supply is 0.
# @param min_liquidity Minimum number of UNI sender will mint if total UNI supply is greater than 0.
# @param max_tokens Maximum number of tokens deposited. Deposits max amount if total UNI supply is 0.
# @param deadline Time after which this transaction can no longer be executed.
# @return The amount of UNI minted.
@public
@payable
def addLiquidity(min_liquidity: uint256, max_tokens: uint256, deadline: timestamp) -> uint256:
    assert deadline > block.timestamp and (max_tokens > 0 and msg.value > 0)
    total_liquidity: uint256 = self.totalSupply
    if total_liquidity > 0:
        assert min_liquidity > 0
        eth_reserve: uint256(wei) = self.balance - msg.value
        token_reserve: uint256 = self.token.balanceOf(self)
        token_amount: uint256 = msg.value * token_reserve / eth_reserve + 1
        liquidity_minted: uint256 = msg.value * total_liquidity / eth_reserve
        assert max_tokens >= token_amount and liquidity_minted >= min_liquidity
        self.balances[msg.sender] += liquidity_minted
        self.totalSupply = total_liquidity + liquidity_minted
        assert self.token.transferFrom(msg.sender, self, token_amount)
        log.AddLiquidity(msg.sender, msg.value, token_amount)
        log.Transfer(ZERO_ADDRESS, msg.sender, liquidity_minted)
        return liquidity_minted
    else:
        assert (self.factory != ZERO_ADDRESS and self.token != ZERO_ADDRESS) and msg.value >= 1000000000
        assert self.factory.getExchange(self.token) == self
        token_amount: uint256 = max_tokens
        initial_liquidity: uint256 = as_unitless_number(self.balance)
        self.totalSupply = initial_liquidity
        self.balances[msg.sender] = initial_liquidity
        assert self.token.transferFrom(msg.sender, self, token_amount)
        log.AddLiquidity(msg.sender, msg.value, token_amount)
        log.Transfer(ZERO_ADDRESS, msg.sender, initial_liquidity)
        return initial_liquidity

# @dev Burn UNI tokens to withdraw ETH and Tokens at current ratio.
# @param amount Amount of UNI burned.
# @param min_eth Minimum ETH withdrawn.
# @param min_tokens Minimum Tokens withdrawn.
# @param deadline Time after which this transaction can no longer be executed.
# @return The amount of ETH and Tokens withdrawn.
@public
def removeLiquidity(amount: uint256, min_eth: uint256(wei), min_tokens: uint256, deadline: timestamp) -> (uint256(wei), uint256):
    assert (amount > 0 and deadline > block.timestamp) and (min_eth > 0 and min_tokens > 0)
    total_liquidity: uint256 = self.totalSupply
    assert total_liquidity > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_amount: uint256(wei) = amount * self.balance / total_liquidity
    token_amount: uint256 = amount * token_reserve / total_liquidity
    assert eth_amount >= min_eth and token_amount >= min_tokens
    self.balances[msg.sender] -= amount
    self.totalSupply = total_liquidity - amount
    send(msg.sender, eth_amount)
    assert self.token.transfer(msg.sender, token_amount)
    log.RemoveLiquidity(msg.sender, eth_amount, token_amount)
    log.Transfer(msg.sender, ZERO_ADDRESS, amount)
    return eth_amount, token_amount

# @dev Pricing function for converting between ETH and Tokens.
# @param input_amount Amount of ETH or Tokens being sold.
# @param input_reserve Amount of ETH or Tokens (input type) in exchange reserves.
# @param output_reserve Amount of ETH or Tokens (output type) in exchange reserves.
# @return Amount of ETH or Tokens bought.
@private
@constant
def getInputPrice(input_amount: uint256, input_reserve: uint256, output_reserve: uint256) -> uint256:
    assert input_reserve > 0 and output_reserve > 0
    input_amount_with_fee: uint256 = input_amount * 997
    numerator: uint256 = input_amount_with_fee * output_reserve
    denominator: uint256 = (input_reserve * 1000) + input_amount_with_fee
    return numerator / denominator

# @dev Pricing function for converting between ETH and Tokens.
# @param output_amount Amount of ETH or Tokens being bought.
# @param input_reserve Amount of ETH or Tokens (input type) in exchange reserves.
# @param output_reserve Amount of ETH or Tokens (output type) in exchange reserves.
# @return Amount of ETH or Tokens sold.
@private
@constant
def getOutputPrice(output_amount: uint256, input_reserve: uint256, output_reserve: uint256) -> uint256:
    assert input_reserve > 0 and output_reserve > 0
    numerator: uint256 = input_reserve * output_amount * 1000
    denominator: uint256 = (output_reserve - output_amount) * 997
    return numerator / denominator + 1

@private
def ethToTokenInput(eth_sold: uint256(wei), min_tokens: uint256, deadline: timestamp, buyer: address, recipient: address) -> uint256:
    assert deadline >= block.timestamp and (eth_sold > 0 and min_tokens > 0)
    token_reserve: uint256 = self.token.balanceOf(self)
    tokens_bought: uint256 = self.getInputPrice(as_unitless_number(eth_sold), as_unitless_number(self.balance - eth_sold), token_reserve)
    assert tokens_bought >= min_tokens
    assert self.token.transfer(recipient, tokens_bought)
    log.TokenPurchase(buyer, eth_sold, tokens_bought)
    return tokens_bought

# @notice Convert ETH to Tokens.
# @dev User specifies exact input (msg.value).
# @dev User cannot specify minimum output or deadline.
@public
@payable
def __default__():
    self.ethToTokenInput(msg.value, 1, block.timestamp, msg.sender, msg.sender)

# @notice Convert ETH to Tokens.
# @dev User specifies exact input (msg.value) and minimum output.
# @param min_tokens Minimum Tokens bought.
# @param deadline Time after which this transaction can no longer be executed.
# @return Amount of Tokens bought.
@public
@payable
def ethToTokenSwapInput(min_tokens: uint256, deadline: timestamp) -> uint256:
    return self.ethToTokenInput(msg.value, min_tokens, deadline, msg.sender, msg.sender)

# @notice Convert ETH to Tokens and transfers Tokens to recipient.
# @dev User specifies exact input (msg.value) and minimum output
# @param min_tokens Minimum Tokens bought.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output Tokens.
# @return Amount of Tokens bought.
@public
@payable
def ethToTokenTransferInput(min_tokens: uint256, deadline: timestamp, recipient: address) -> uint256:
    assert recipient != self and recipient != ZERO_ADDRESS
    return self.ethToTokenInput(msg.value, min_tokens, deadline, msg.sender, recipient)

@private
def ethToTokenOutput(tokens_bought: uint256, max_eth: uint256(wei), deadline: timestamp, buyer: address, recipient: address) -> uint256(wei):
    assert deadline >= block.timestamp and (tokens_bought > 0 and max_eth > 0)
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_sold: uint256 = self.getOutputPrice(tokens_bought, as_unitless_number(self.balance - max_eth), token_reserve)
    # Throws if eth_sold > max_eth
    eth_refund: uint256(wei) = max_eth - as_wei_value(eth_sold, 'wei')
    if eth_refund > 0:
        send(buyer, eth_refund)
    assert self.token.transfer(recipient, tokens_bought)
    log.TokenPurchase(buyer, as_wei_value(eth_sold, 'wei'), tokens_bought)
    return as_wei_value(eth_sold, 'wei')

# @notice Convert ETH to Tokens.
# @dev User specifies maximum input (msg.value) and exact output.
# @param tokens_bought Amount of tokens bought.
# @param deadline Time after which this transaction can no longer be executed.
# @return Amount of ETH sold.
@public
@payable
def ethToTokenSwapOutput(tokens_bought: uint256, deadline: timestamp) -> uint256(wei):
    return self.ethToTokenOutput(tokens_bought, msg.value, deadline, msg.sender, msg.sender)

# @notice Convert ETH to Tokens and transfers Tokens to recipient.
# @dev User specifies maximum input (msg.value) and exact output.
# @param tokens_bought Amount of tokens bought.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output Tokens.
# @return Amount of ETH sold.
@public
@payable
def ethToTokenTransferOutput(tokens_bought: uint256, deadline: timestamp, recipient: address) -> uint256(wei):
    assert recipient != self and recipient != ZERO_ADDRESS
    return self.ethToTokenOutput(tokens_bought, msg.value, deadline, msg.sender, recipient)

@private
def tokenToEthInput(tokens_sold: uint256, min_eth: uint256(wei), deadline: timestamp, buyer: address, recipient: address) -> uint256(wei):
    assert deadline >= block.timestamp and (tokens_sold > 0 and min_eth > 0)
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_bought: uint256 = self.getInputPrice(tokens_sold, token_reserve, as_unitless_number(self.balance))
    wei_bought: uint256(wei) = as_wei_value(eth_bought, 'wei')
    assert wei_bought >= min_eth
    send(recipient, wei_bought)
    assert self.token.transferFrom(buyer, self, tokens_sold)
    log.EthPurchase(buyer, tokens_sold, wei_bought)
    return wei_bought


# @notice Convert Tokens to ETH.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_eth Minimum ETH purchased.
# @param deadline Time after which this transaction can no longer be executed.
# @return Amount of ETH bought.
@public
def tokenToEthSwapInput(tokens_sold: uint256, min_eth: uint256(wei), deadline: timestamp) -> uint256(wei):
    return self.tokenToEthInput(tokens_sold, min_eth, deadline, msg.sender, msg.sender)

# @notice Convert Tokens to ETH and transfers ETH to recipient.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_eth Minimum ETH purchased.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @return Amount of ETH bought.
@public
def tokenToEthTransferInput(tokens_sold: uint256, min_eth: uint256(wei), deadline: timestamp, recipient: address) -> uint256(wei):
    assert recipient != self and recipient != ZERO_ADDRESS
    return self.tokenToEthInput(tokens_sold, min_eth, deadline, msg.sender, recipient)

@private
def tokenToEthOutput(eth_bought: uint256(wei), max_tokens: uint256, deadline: timestamp, buyer: address, recipient: address) -> uint256:
    assert deadline >= block.timestamp and eth_bought > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    tokens_sold: uint256 = self.getOutputPrice(as_unitless_number(eth_bought), token_reserve, as_unitless_number(self.balance))
    # tokens sold is always > 0
    assert max_tokens >= tokens_sold
    send(recipient, eth_bought)
    assert self.token.transferFrom(buyer, self, tokens_sold)
    log.EthPurchase(buyer, tokens_sold, eth_bought)
    return tokens_sold

# @notice Convert Tokens to ETH.
# @dev User specifies maximum input and exact output.
# @param eth_bought Amount of ETH purchased.
# @param max_tokens Maximum Tokens sold.
# @param deadline Time after which this transaction can no longer be executed.
# @return Amount of Tokens sold.
@public
def tokenToEthSwapOutput(eth_bought: uint256(wei), max_tokens: uint256, deadline: timestamp) -> uint256:
    return self.tokenToEthOutput(eth_bought, max_tokens, deadline, msg.sender, msg.sender)

# @notice Convert Tokens to ETH and transfers ETH to recipient.
# @dev User specifies maximum input and exact output.
# @param eth_bought Amount of ETH purchased.
# @param max_tokens Maximum Tokens sold.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @return Amount of Tokens sold.
@public
def tokenToEthTransferOutput(eth_bought: uint256(wei), max_tokens: uint256, deadline: timestamp, recipient: address) -> uint256:
    assert recipient != self and recipient != ZERO_ADDRESS
    return self.tokenToEthOutput(eth_bought, max_tokens, deadline, msg.sender, recipient)

@private
def tokenToTokenInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, buyer: address, recipient: address, exchange_addr: address) -> uint256:
    assert (deadline >= block.timestamp and tokens_sold > 0) and (min_tokens_bought > 0 and min_eth_bought > 0)
    assert exchange_addr != self and exchange_addr != ZERO_ADDRESS
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_bought: uint256 = self.getInputPrice(tokens_sold, token_reserve, as_unitless_number(self.balance))
    wei_bought: uint256(wei) = as_wei_value(eth_bought, 'wei')
    assert wei_bought >= min_eth_bought
    assert self.token.transferFrom(buyer, self, tokens_sold)
    tokens_bought: uint256 = Exchange(exchange_addr).ethToTokenTransferInput(min_tokens_bought, deadline, recipient, value=wei_bought)
    log.EthPurchase(buyer, tokens_sold, wei_bought)
    return tokens_bought

# @notice Convert Tokens (self.token) to Tokens (token_addr).
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_tokens_bought Minimum Tokens (token_addr) purchased.
# @param min_eth_bought Minimum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (token_addr) bought.
@public
def tokenToTokenSwapInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, token_addr: address) -> uint256:
    exchange_addr: address = self.factory.getExchange(token_addr)
    return self.tokenToTokenInput(tokens_sold, min_tokens_bought, min_eth_bought, deadline, msg.sender, msg.sender, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (token_addr) and transfers
#         Tokens (token_addr) to recipient.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_tokens_bought Minimum Tokens (token_addr) purchased.
# @param min_eth_bought Minimum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (token_addr) bought.
@public
def tokenToTokenTransferInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, recipient: address, token_addr: address) -> uint256:
    exchange_addr: address = self.factory.getExchange(token_addr)
    return self.tokenToTokenInput(tokens_sold, min_tokens_bought, min_eth_bought, deadline, msg.sender, recipient, exchange_addr)

@private
def tokenToTokenOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, buyer: address, recipient: address, exchange_addr: address) -> uint256:
    assert deadline >= block.timestamp and (tokens_bought > 0 and max_eth_sold > 0)
    assert exchange_addr != self and exchange_addr != ZERO_ADDRESS
    eth_bought: uint256(wei) = Exchange(exchange_addr).getEthToTokenOutputPrice(tokens_bought)
    token_reserve: uint256 = self.token.balanceOf(self)
    tokens_sold: uint256 = self.getOutputPrice(as_unitless_number(eth_bought), token_reserve, as_unitless_number(self.balance))
    # tokens sold is always > 0
    assert max_tokens_sold >= tokens_sold and max_eth_sold >= eth_bought
    assert self.token.transferFrom(buyer, self, tokens_sold)
    eth_sold: uint256(wei) = Exchange(exchange_addr).ethToTokenTransferOutput(tokens_bought, deadline, recipient, value=eth_bought)
    log.EthPurchase(buyer, tokens_sold, eth_bought)
    return tokens_sold

# @notice Convert Tokens (self.token) to Tokens (token_addr).
# @dev User specifies maximum input and exact output.
# @param tokens_bought Amount of Tokens (token_addr) bought.
# @param max_tokens_sold Maximum Tokens (self.token) sold.
# @param max_eth_sold Maximum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (self.token) sold.
@public
def tokenToTokenSwapOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, token_addr: address) -> uint256:
    exchange_addr: address = self.factory.getExchange(token_addr)
    return self.tokenToTokenOutput(tokens_bought, max_tokens_sold, max_eth_sold, deadline, msg.sender, msg.sender, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (token_addr) and transfers
#         Tokens (token_addr) to recipient.
# @dev User specifies maximum input and exact output.
# @param tokens_bought Amount of Tokens (token_addr) bought.
# @param max_tokens_sold Maximum Tokens (self.token) sold.
# @param max_eth_sold Maximum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (self.token) sold.
@public
def tokenToTokenTransferOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, recipient: address, token_addr: address) -> uint256:
    exchange_addr: address = self.factory.getExchange(token_addr)
    return self.tokenToTokenOutput(tokens_bought, max_tokens_sold, max_eth_sold, deadline, msg.sender, recipient, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (exchange_addr.token).
# @dev Allows trades through contracts that were not deployed from the same factory.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_tokens_bought Minimum Tokens (token_addr) purchased.
# @param min_eth_bought Minimum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param exchange_addr The address of the exchange for the token being purchased.
# @return Amount of Tokens (exchange_addr.token) bought.
@public
def tokenToExchangeSwapInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, exchange_addr: address) -> uint256:
    return self.tokenToTokenInput(tokens_sold, min_tokens_bought, min_eth_bought, deadline, msg.sender, msg.sender, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (exchange_addr.token) and transfers
#         Tokens (exchange_addr.token) to recipient.
# @dev Allows trades through contracts that were not deployed from the same factory.
# @dev User specifies exact input and minimum output.
# @param tokens_sold Amount of Tokens sold.
# @param min_tokens_bought Minimum Tokens (token_addr) purchased.
# @param min_eth_bought Minimum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @param exchange_addr The address of the exchange for the token being purchased.
# @return Amount of Tokens (exchange_addr.token) bought.
@public
def tokenToExchangeTransferInput(tokens_sold: uint256, min_tokens_bought: uint256, min_eth_bought: uint256(wei), deadline: timestamp, recipient: address, exchange_addr: address) -> uint256:
    assert recipient != self
    return self.tokenToTokenInput(tokens_sold, min_tokens_bought, min_eth_bought, deadline, msg.sender, recipient, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (exchange_addr.token).
# @dev Allows trades through contracts that were not deployed from the same factory.
# @dev User specifies maximum input and exact output.
# @param tokens_bought Amount of Tokens (token_addr) bought.
# @param max_tokens_sold Maximum Tokens (self.token) sold.
# @param max_eth_sold Maximum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param exchange_addr The address of the exchange for the token being purchased.
# @return Amount of Tokens (self.token) sold.
@public
def tokenToExchangeSwapOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, exchange_addr: address) -> uint256:
    return self.tokenToTokenOutput(tokens_bought, max_tokens_sold, max_eth_sold, deadline, msg.sender, msg.sender, exchange_addr)

# @notice Convert Tokens (self.token) to Tokens (exchange_addr.token) and transfers
#         Tokens (exchange_addr.token) to recipient.
# @dev Allows trades through contracts that were not deployed from the same factory.
# @dev User specifies maximum input and exact output.
# @param tokens_bought Amount of Tokens (token_addr) bought.
# @param max_tokens_sold Maximum Tokens (self.token) sold.
# @param max_eth_sold Maximum ETH purchased as intermediary.
# @param deadline Time after which this transaction can no longer be executed.
# @param recipient The address that receives output ETH.
# @param token_addr The address of the token being purchased.
# @return Amount of Tokens (self.token) sold.
@public
def tokenToExchangeTransferOutput(tokens_bought: uint256, max_tokens_sold: uint256, max_eth_sold: uint256(wei), deadline: timestamp, recipient: address, exchange_addr: address) -> uint256:
    assert recipient != self
    return self.tokenToTokenOutput(tokens_bought, max_tokens_sold, max_eth_sold, deadline, msg.sender, recipient, exchange_addr)

# @notice Public price function for ETH to Token trades with an exact input.
# @param eth_sold Amount of ETH sold.
# @return Amount of Tokens that can be bought with input ETH.
@public
@constant
def getEthToTokenInputPrice(eth_sold: uint256(wei)) -> uint256:
    assert eth_sold > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    return self.getInputPrice(as_unitless_number(eth_sold), as_unitless_number(self.balance), token_reserve)

# @notice Public price function for ETH to Token trades with an exact output.
# @param tokens_bought Amount of Tokens bought.
# @return Amount of ETH needed to buy output Tokens.
@public
@constant
def getEthToTokenOutputPrice(tokens_bought: uint256) -> uint256(wei):
    assert tokens_bought > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_sold: uint256 = self.getOutputPrice(tokens_bought, as_unitless_number(self.balance), token_reserve)
    return as_wei_value(eth_sold, 'wei')

# @notice Public price function for Token to ETH trades with an exact input.
# @param tokens_sold Amount of Tokens sold.
# @return Amount of ETH that can be bought with input Tokens.
@public
@constant
def getTokenToEthInputPrice(tokens_sold: uint256) -> uint256(wei):
    assert tokens_sold > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    eth_bought: uint256 = self.getInputPrice(tokens_sold, token_reserve, as_unitless_number(self.balance))
    return as_wei_value(eth_bought, 'wei')

# @notice Public price function for Token to ETH trades with an exact output.
# @param eth_bought Amount of output ETH.
# @return Amount of Tokens needed to buy output ETH.
@public
@constant
def getTokenToEthOutputPrice(eth_bought: uint256(wei)) -> uint256:
    assert eth_bought > 0
    token_reserve: uint256 = self.token.balanceOf(self)
    return self.getOutputPrice(as_unitless_number(eth_bought), token_reserve, as_unitless_number(self.balance))

# @return Address of Token that is sold on this exchange.
@public
@constant
def tokenAddress() -> address:
    return self.token

# @return Address of factory that created this exchange.
@public
@constant
def factoryAddress() -> address(Factory):
    return self.factory

# ERC20 compatibility for exchange liquidity modified from
# https://github.com/ethereum/vyper/blob/master/examples/tokens/ERC20.vy
@public
@constant
def balanceOf(_owner : address) -> uint256:
    return self.balances[_owner]

@public
def transfer(_to : address, _value : uint256) -> bool:
    self.balances[msg.sender] -= _value
    self.balances[_to] += _value
    log.Transfer(msg.sender, _to, _value)
    return True

@public
def transferFrom(_from : address, _to : address, _value : uint256) -> bool:
    self.balances[_from] -= _value
    self.balances[_to] += _value
    self.allowances[_from][msg.sender] -= _value
    log.Transfer(_from, _to, _value)
    return True

@public
def approve(_spender : address, _value : uint256) -> bool:
    self.allowances[msg.sender][_spender] = _value
    log.Approval(msg.sender, _spender, _value)
    return True

@public
@constant
def allowance(_owner : address, _spender : address) -> uint256:
    return self.allowances[_owner][_spender]