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Contract Name:
UniswapV2_ZapOut_General_V2

Contract Source Code:

File 1 of 1 : UniswapV2_ZapOut_General_V2

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

pragma solidity ^0.5.0;

/**
 * @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.
     *
     * _Available since v2.4.0._
     */
    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.
     *
     * _Available since v2.4.0._
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @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.
     *
     * _Available since v2.4.0._
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity ^0.5.0;

/*
 * @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.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor() internal {}

    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view 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/ownership/Ownable.sol

pragma solidity ^0.5.0;

/**
 * @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.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
    address private _owner;

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

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

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

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

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _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 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 onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(
            newOwner != address(0),
            "Ownable: new owner is the zero address"
        );
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

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

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
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/utils/Address.sol

pragma solidity ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;


            bytes32 accountHash
         = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            codehash := extcodehash(account)
        }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account)
        internal
        pure
        returns (address payable)
    {
        return address(uint160(account));
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(
            address(this).balance >= amount,
            "Address: insufficient balance"
        );

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(
            success,
            "Address: unable to send value, recipient may have reverted"
        );
    }
}

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

pragma solidity ^0.5.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 *
 * _Since v2.5.0:_ this module is now much more gas efficient, given net gas
 * metering changes introduced in the Istanbul hardfork.
 */
contract ReentrancyGuard {
    bool private _notEntered;

    constructor() internal {
        // Storing an initial non-zero value makes deployment a bit more
        // expensive, but in exchange the refund on every call to nonReentrant
        // will be lower in amount. Since refunds are capped to a percetange of
        // the total transaction's gas, it is best to keep them low in cases
        // like this one, to increase the likelihood of the full refund coming
        // into effect.
        _notEntered = true;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_notEntered, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _notEntered = false;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _notEntered = true;
    }
}

// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol

pragma solidity ^0.5.0;

/**
 * @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 ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        callOptionalReturn(
            token,
            abi.encodeWithSelector(token.transfer.selector, to, value)
        );
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        callOptionalReturn(
            token,
            abi.encodeWithSelector(token.transferFrom.selector, from, to, value)
        );
    }

    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(
            token,
            abi.encodeWithSelector(token.approve.selector, spender, value)
        );
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(
            value
        );
        callOptionalReturn(
            token,
            abi.encodeWithSelector(
                token.approve.selector,
                spender,
                newAllowance
            )
        );
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(
            value,
            "SafeERC20: decreased allowance below zero"
        );
        callOptionalReturn(
            token,
            abi.encodeWithSelector(
                token.approve.selector,
                spender,
                newAllowance
            )
        );
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) {
            // Return data is optional
            // solhint-disable-next-line max-line-length
            require(
                abi.decode(returndata, (bool)),
                "SafeERC20: ERC20 operation did not succeed"
            );
        }
    }
}

// File: contracts/UniswapV2/UniswapV2Router.sol

pragma solidity 0.5.12;

interface IUniswapV2Router02 {
    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );

    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountA, uint256 amountB);

    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountToken, uint256 amountETH);

    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB);

    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH);

    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountETH);

    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable;

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;

    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) external pure returns (uint256 amountB);

    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountOut);

    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountIn);

    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);

    function getAmountsIn(uint256 amountOut, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
}

// File: contracts/UniswapV2/UniswapV2_ZapOut_General_V2.sol

pragma solidity 0.5.12;

// Copyright (C) 2020 dipeshsukhani, nodarjanashia, suhailg, apoorvlathey, sebaudet, sumit

// 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 2 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.
//
// Visit <https://www.gnu.org/licenses/>for a copy of the GNU Affero General Public License

///@author Zapper
///@notice this contract implements one click removal of liquidity from Uniswap V2 pools, receiving ETH, ERC tokens or both.

library TransferHelper {
    function safeApprove(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(
            abi.encodeWithSelector(0x095ea7b3, to, value)
        );
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            "TransferHelper: APPROVE_FAILED"
        );
    }

    function safeTransfer(
        address token,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(
            abi.encodeWithSelector(0xa9059cbb, to, value)
        );
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            "TransferHelper: TRANSFER_FAILED"
        );
    }

    function safeTransferFrom(
        address token,
        address from,
        address to,
        uint256 value
    ) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(
            abi.encodeWithSelector(0x23b872dd, from, to, value)
        );
        require(
            success && (data.length == 0 || abi.decode(data, (bool))),
            "TransferHelper: TRANSFER_FROM_FAILED"
        );
    }
}

interface Iuniswap {
    // converting ERC20 to ERC20 and transfer
    function tokenToTokenTransferInput(
        uint256 tokens_sold,
        uint256 min_tokens_bought,
        uint256 min_eth_bought,
        uint256 deadline,
        address recipient,
        address token_addr
    ) external returns (uint256 tokens_bought);

    function tokenToTokenSwapInput(
        uint256 tokens_sold,
        uint256 min_tokens_bought,
        uint256 min_eth_bought,
        uint256 deadline,
        address token_addr
    ) external returns (uint256 tokens_bought);

    function getTokenToEthInputPrice(uint256 tokens_sold)
        external
        view
        returns (uint256 eth_bought);

    function tokenToEthTransferInput(
        uint256 tokens_sold,
        uint256 min_eth,
        uint256 deadline,
        address recipient
    ) external returns (uint256 eth_bought);

    function ethToTokenSwapInput(uint256 min_tokens, uint256 deadline)
        external
        payable
        returns (uint256 tokens_bought);

    function ethToTokenTransferInput(
        uint256 min_tokens,
        uint256 deadline,
        address recipient
    ) external payable returns (uint256 tokens_bought);

    function balanceOf(address _owner) external view returns (uint256);

    function transfer(address _to, uint256 _value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 tokens
    ) external returns (bool success);
}

interface IUniswapV2Pair {
    function token0() external pure returns (address);

    function token1() external pure returns (address);

    function totalSupply() external view returns (uint256);

    function getReserves()
        external
        view
        returns (
            uint112 _reserve0,
            uint112 _reserve1,
            uint32 _blockTimestampLast
        );
}

interface IWETH {
    function deposit() external payable;

    function transfer(address to, uint256 value) external returns (bool);

    function withdraw(uint256) external;
}

interface IUniswapV2Factory {
    function getPair(address tokenA, address tokenB)
        external
        view
        returns (address);
}

contract UniswapV2_ZapOut_General_V2 is ReentrancyGuard, Ownable {
    using SafeMath for uint256;
    using Address for address;
    bool private stopped = false;
    uint16 public goodwill;
    address public dzgoodwillAddress;

    IUniswapV2Router02 public uniswapV2Router = IUniswapV2Router02(
        0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
    );

    IUniswapV2Factory public UniSwapV2FactoryAddress = IUniswapV2Factory(
        0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f
    );

    address public wethTokenAddress = address(
        0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2
    );

    constructor(uint16 _goodwill, address _dzgoodwillAddress) public {
        goodwill = _goodwill;
        dzgoodwillAddress = _dzgoodwillAddress;
    }

    // circuit breaker modifiers
    modifier stopInEmergency {
        if (stopped) {
            revert("Temporarily Paused");
        } else {
            _;
        }
    }

    /**
    @notice This function is used to zapout of given Uniswap pair in the bounded tokens
    @param _FromUniPoolAddress The uniswap pair address to zapout
    @param _IncomingLP The amount of LP
    @return the amount of pair tokens received after zapout
     */
    function ZapOut2PairToken(
        address _FromUniPoolAddress,
        uint256 _IncomingLP
    )
        public
        payable
        nonReentrant
        stopInEmergency
        returns (uint256 amountA, uint256 amountB)
    {
        IUniswapV2Pair pair = IUniswapV2Pair(_FromUniPoolAddress);

        require(address(pair) != address(0), "Error: Invalid Unipool Address");

        //get reserves
        address token0 = pair.token0();
        address token1 = pair.token1();

        TransferHelper.safeTransferFrom(
            _FromUniPoolAddress,
            msg.sender,
            address(this),
            _IncomingLP
        );

        uint256 goodwillPortion = _transferGoodwill(
            _FromUniPoolAddress,
            _IncomingLP
        );

        TransferHelper.safeApprove(
            _FromUniPoolAddress,
            address(uniswapV2Router),
            SafeMath.sub(_IncomingLP, goodwillPortion)
        );

        if (token0 == wethTokenAddress || token1 == wethTokenAddress) {
            address _token = token0 == wethTokenAddress ? token1 : token0;
            (amountA, amountB) = uniswapV2Router.removeLiquidityETH(
                _token,
                SafeMath.sub(_IncomingLP, goodwillPortion),
                1,
                1,
                msg.sender,
                now + 60
            );
        } else {
            (amountA, amountB) = uniswapV2Router.removeLiquidity(
                token0,
                token1,
                SafeMath.sub(_IncomingLP, goodwillPortion),
                1,
                1,
                msg.sender,
                now + 60
            );
        }
    }

    /**
    @notice This function is used to zapout of given Uniswap pair in ETH/ERC20 Tokens
    @param _ToTokenContractAddress The ERC20 token to zapout in (address(0x00) if ether)
    @param _FromUniPoolAddress The uniswap pair address to zapout from
    @param _IncomingLP The amount of LP
    @return the amount of eth/tokens received after zapout
     */
    function ZapOut(
        address _ToTokenContractAddress,
        address _FromUniPoolAddress,
        uint256 _IncomingLP,
        uint256 _minTokensRec
    ) public payable nonReentrant stopInEmergency returns (uint256) {
        IUniswapV2Pair pair = IUniswapV2Pair(_FromUniPoolAddress);

        require(address(pair) != address(0), "Error: Invalid Unipool Address");

        //get pair tokens
        address token0 = pair.token0();
        address token1 = pair.token1();

        TransferHelper.safeTransferFrom(
            _FromUniPoolAddress,
            msg.sender,
            address(this),
            _IncomingLP
        );

        uint256 goodwillPortion = _transferGoodwill(
            _FromUniPoolAddress,
            _IncomingLP
        );

        TransferHelper.safeApprove(
            _FromUniPoolAddress,
            address(uniswapV2Router),
            SafeMath.sub(_IncomingLP, goodwillPortion)
        );

        (uint256 amountA, uint256 amountB) = uniswapV2Router.removeLiquidity(
            token0,
            token1,
            SafeMath.sub(_IncomingLP, goodwillPortion),
            1,
            1,
            address(this),
            now + 60
        );

        uint256 tokenBought;
        if (
            canSwapFromV2(_ToTokenContractAddress, token0) &&
            canSwapFromV2(_ToTokenContractAddress, token1)
        ) {
            tokenBought = swapFromV2(token0, _ToTokenContractAddress, amountA);
            tokenBought += swapFromV2(token1, _ToTokenContractAddress, amountB);
        } else if (canSwapFromV2(_ToTokenContractAddress, token0)) {
            uint256 token0Bought = swapFromV2(token1, token0, amountB);
            tokenBought = swapFromV2(
                token0,
                _ToTokenContractAddress,
                token0Bought.add(amountA)
            );
        } else if (canSwapFromV2(_ToTokenContractAddress, token1)) {
            uint256 token1Bought = swapFromV2(token0, token1, amountA);
            tokenBought = swapFromV2(
                token1,
                _ToTokenContractAddress,
                token1Bought.add(amountB)
            );
        }

        require(tokenBought >= _minTokensRec, "High slippage");

        if (_ToTokenContractAddress == address(0)) {
            msg.sender.transfer(tokenBought);
        } else {
            TransferHelper.safeTransfer(
                _ToTokenContractAddress,
                msg.sender,
                tokenBought
            );
        }

        return tokenBought;
    }

    //swaps _fromToken for _toToken
    //for eth, address(0) otherwise ERC token address
    function swapFromV2(
        address _fromToken,
        address _toToken,
        uint256 amount
    ) internal returns (uint256) {
        require(
            _fromToken != address(0) || _toToken != address(0),
            "Invalid Exchange values"
        );
        if (_fromToken == _toToken) return amount;

        require(canSwapFromV2(_fromToken, _toToken), "Cannot be exchanged");
        require(amount > 0, "Invalid amount");

        if (_fromToken == address(0)) {
            if (_toToken == wethTokenAddress) {
                IWETH(wethTokenAddress).deposit.value(amount)();
                return amount;
            }
            address[] memory path = new address[](2);
            path[0] = wethTokenAddress;
            path[1] = _toToken;
            uint256 minTokens = uniswapV2Router.getAmountsOut(amount, path)[1];
            minTokens = SafeMath.div(
                SafeMath.mul(minTokens, SafeMath.sub(10000, 200)),
                10000
            );
            uint256[] memory amounts = uniswapV2Router
                .swapExactETHForTokens
                .value(amount)(minTokens, path, address(this), now + 180);
            return amounts[1];
        } else if (_toToken == address(0)) {
            if (_fromToken == wethTokenAddress) {
                IWETH(wethTokenAddress).withdraw(amount);
                return amount;
            }
            address[] memory path = new address[](2);
            TransferHelper.safeApprove(
                _fromToken,
                address(uniswapV2Router),
                amount
            );
            path[0] = _fromToken;
            path[1] = wethTokenAddress;
            uint256 minTokens = uniswapV2Router.getAmountsOut(amount, path)[1];
            minTokens = SafeMath.div(
                SafeMath.mul(minTokens, SafeMath.sub(10000, 200)),
                10000
            );
            uint256[] memory amounts = uniswapV2Router.swapExactTokensForETH(
                amount,
                minTokens,
                path,
                address(this),
                now + 180
            );
            return amounts[1];
        } else {
            TransferHelper.safeApprove(
                _fromToken,
                address(uniswapV2Router),
                amount
            );
            uint256 returnedAmount = _swapTokenToTokenV2(
                _fromToken,
                _toToken,
                amount
            );
            require(returnedAmount > 0, "Error in swap");
            return returnedAmount;
        }
    }

    //swaps 2 ERC tokens (UniV2)
    function _swapTokenToTokenV2(
        address _fromToken,
        address _toToken,
        uint256 amount
    ) internal returns (uint256) {
        IUniswapV2Pair pair1 = IUniswapV2Pair(
            UniSwapV2FactoryAddress.getPair(_fromToken, wethTokenAddress)
        );
        IUniswapV2Pair pair2 = IUniswapV2Pair(
            UniSwapV2FactoryAddress.getPair(_toToken, wethTokenAddress)
        );
        IUniswapV2Pair pair3 = IUniswapV2Pair(
            UniSwapV2FactoryAddress.getPair(_fromToken, _toToken)
        );

        uint256[] memory amounts;

        if (_haveReserve(pair3)) {
            address[] memory path = new address[](2);
            path[0] = _fromToken;
            path[1] = _toToken;
            uint256 minTokens = uniswapV2Router.getAmountsOut(amount, path)[1];
            minTokens = SafeMath.div(
                SafeMath.mul(minTokens, SafeMath.sub(10000, 200)),
                10000
            );
            amounts = uniswapV2Router.swapExactTokensForTokens(
                amount,
                minTokens,
                path,
                address(this),
                now + 180
            );
            return amounts[1];
        } else if (_haveReserve(pair1) && _haveReserve(pair2)) {
            address[] memory path = new address[](3);
            path[0] = _fromToken;
            path[1] = wethTokenAddress;
            path[2] = _toToken;
            uint256 minTokens = uniswapV2Router.getAmountsOut(amount, path)[2];
            minTokens = SafeMath.div(
                SafeMath.mul(minTokens, SafeMath.sub(10000, 200)),
                10000
            );
            amounts = uniswapV2Router.swapExactTokensForTokens(
                amount,
                minTokens,
                path,
                address(this),
                now + 180
            );
            return amounts[2];
        }
        return 0;
    }

    function canSwapFromV2(address _fromToken, address _toToken)
        public
        view
        returns (bool)
    {
        require(
            _fromToken != address(0) || _toToken != address(0),
            "Invalid Exchange values"
        );

        if (_fromToken == _toToken) return true;

        if (_fromToken == address(0) || _fromToken == wethTokenAddress) {
            if (_toToken == wethTokenAddress || _toToken == address(0))
                return true;
            IUniswapV2Pair pair = IUniswapV2Pair(
                UniSwapV2FactoryAddress.getPair(_toToken, wethTokenAddress)
            );
            if (_haveReserve(pair)) return true;
        } else if (_toToken == address(0) || _toToken == wethTokenAddress) {
            if (_fromToken == wethTokenAddress || _fromToken == address(0))
                return true;
            IUniswapV2Pair pair = IUniswapV2Pair(
                UniSwapV2FactoryAddress.getPair(_fromToken, wethTokenAddress)
            );
            if (_haveReserve(pair)) return true;
        } else {
            IUniswapV2Pair pair1 = IUniswapV2Pair(
                UniSwapV2FactoryAddress.getPair(_fromToken, wethTokenAddress)
            );
            IUniswapV2Pair pair2 = IUniswapV2Pair(
                UniSwapV2FactoryAddress.getPair(_toToken, wethTokenAddress)
            );
            IUniswapV2Pair pair3 = IUniswapV2Pair(
                UniSwapV2FactoryAddress.getPair(_fromToken, _toToken)
            );
            if (_haveReserve(pair1) && _haveReserve(pair2)) return true;
            if (_haveReserve(pair3)) return true;
        }
        return false;
    }

    //checks if the UNI v2 contract have reserves to swap tokens
    function _haveReserve(IUniswapV2Pair pair) internal view returns (bool) {
        if (address(pair) != address(0)) {
            uint256 totalSupply = pair.totalSupply();
            if (totalSupply > 0) return true;
        }
    }

    /**
    @notice This function is used to calculate and transfer goodwill
    @param _tokenContractAddress Token in which goodwill is deducted
    @param tokens2Trade The total amount of tokens to be zapped in
    @return The quantity of goodwill deducted
     */
    function _transferGoodwill(
        address _tokenContractAddress,
        uint256 tokens2Trade
    ) internal returns (uint256 goodwillPortion) {
        if (goodwill == 0) {
            return 0;
        }

        goodwillPortion = SafeMath.div(
            SafeMath.mul(tokens2Trade, goodwill),
            10000
        );

        TransferHelper.safeTransfer(
            _tokenContractAddress,
            dzgoodwillAddress,
            goodwillPortion
        );
    }

    function set_new_goodwill(uint16 _new_goodwill) public onlyOwner {
        require(
            _new_goodwill >= 0 && _new_goodwill < 10000,
            "GoodWill Value not allowed"
        );
        goodwill = _new_goodwill;
    }

    function set_new_dzgoodwillAddress(address _new_dzgoodwillAddress)
        public
        onlyOwner
    {
        dzgoodwillAddress = _new_dzgoodwillAddress;
    }

    function inCaseTokengetsStuck(IERC20 _TokenAddress) public onlyOwner {
        uint256 qty = _TokenAddress.balanceOf(address(this));
        TransferHelper.safeTransfer(address(_TokenAddress), owner(), qty);
    }

    // - to Pause the contract
    function toggleContractActive() public onlyOwner {
        stopped = !stopped;
    }

    // - to withdraw any ETH balance sitting in the contract
    function withdraw() public onlyOwner {
        uint256 contractBalance = address(this).balance;
        address payable _to = owner().toPayable();
        _to.transfer(contractBalance);
    }

    function() external payable {}
}

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