nola11/MindchainswapFactory_flat.sol

## MindchainswapFactory_flat.sol

// File: interfaces/IMindchainswapCallee.sol


pragma solidity >=0.5.0;

interface IMindchainswapCallee {
    function mindCall(
        address sender,
        uint256 amount0,
        uint256 amount1,
        bytes calldata data
    ) external;
}
// File: interfaces/IERC20.sol


pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(address indexed owner, address indexed spender, uint256 value);
    event Transfer(address indexed from, address indexed to, uint256 value);

    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    function decimals() external view returns (uint8);

    function totalSupply() external view returns (uint256);

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

    function allowance(address owner, address spender) external view returns (uint256);

    function approve(address spender, uint256 value) external returns (bool);

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

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

// File: libraries/UQ112x112.sol


pragma solidity =0.5.16;

// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))

// range: [0, 2**112 - 1]
// resolution: 1 / 2**112

library UQ112x112 {
    uint224 constant Q112 = 2**112;

    // encode a uint112 as a UQ112x112
    function encode(uint112 y) internal pure returns (uint224 z) {
        z = uint224(y) * Q112; // never overflows
    }

    // divide a UQ112x112 by a uint112, returning a UQ112x112
    function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
        z = x / uint224(y);
    }
}

// File: libraries/Math.sol


pragma solidity =0.5.16;

// a library for performing various math operations

library Math {
    function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = x < y ? x : y;
    }

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint256 y) internal pure returns (uint256 z) {
        if (y > 3) {
            z = y;
            uint256 x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// File: libraries/SafeMath.sol


pragma solidity >=0.5.0 <0.7.0;

// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

library SafeMath {
    function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x + y) >= x, "ds-math-add-overflow");
    }

    function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x - y) <= x, "ds-math-sub-underflow");
    }

    function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require(y == 0 || (z = x * y) / y == x, "ds-math-mul-overflow");
    }
}

// File: interfaces/IMindchainswapERC20.sol


pragma solidity >=0.5.0;

interface IMindchainswapERC20 {
    event Approval(address indexed owner, address indexed spender, uint256 value);
    event Transfer(address indexed from, address indexed to, uint256 value);

    function name() external pure returns (string memory);

    function symbol() external pure returns (string memory);

    function decimals() external pure returns (uint8);

    function totalSupply() external view returns (uint256);

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

    function allowance(address owner, address spender) external view returns (uint256);

    function approve(address spender, uint256 value) external returns (bool);

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

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

    function DOMAIN_SEPARATOR() external view returns (bytes32);

    function PERMIT_TYPEHASH() external pure returns (bytes32);

    function nonces(address owner) external view returns (uint256);

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}
// File: MindchainswapERC20.sol


pragma solidity =0.5.16;


contract MindchainswapERC20 is IMindchainswapERC20 {
    using SafeMath for uint256;

    string public constant name = "Mindchainswap LPs";
    string public constant symbol = "MIND-LP";
    uint8 public constant decimals = 18;
    uint256 public totalSupply;
    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint256) public nonces;

    event Approval(address indexed owner, address indexed spender, uint256 value);
    event Transfer(address indexed from, address indexed to, uint256 value);

    constructor() public {
        uint256 chainId;
        assembly {
            chainId := chainid
        }
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
                keccak256(bytes(name)),
                keccak256(bytes("1")),
                chainId,
                address(this)
            )
        );
    }

    function _mint(address to, uint256 value) internal {
        totalSupply = totalSupply.add(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(address(0), to, value);
    }

    function _burn(address from, uint256 value) internal {
        balanceOf[from] = balanceOf[from].sub(value);
        totalSupply = totalSupply.sub(value);
        emit Transfer(from, address(0), value);
    }

    function _approve(
        address owner,
        address spender,
        uint256 value
    ) private {
        allowance[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    function _transfer(
        address from,
        address to,
        uint256 value
    ) private {
        balanceOf[from] = balanceOf[from].sub(value);
        balanceOf[to] = balanceOf[to].add(value);
        emit Transfer(from, to, value);
    }

    function approve(address spender, uint256 value) external returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transfer(address to, uint256 value) external returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external returns (bool) {
        if (allowance[from][msg.sender] != uint256(-1)) {
            allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
        }
        _transfer(from, to, value);
        return true;
    }

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external {
        require(deadline >= block.timestamp, "Mindchainswap: EXPIRED");
        bytes32 digest = keccak256(
            abi.encodePacked(
                "\x19\x01",
                DOMAIN_SEPARATOR,
                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(recoveredAddress != address(0) && recoveredAddress == owner, "Mindchainswap: INVALID_SIGNATURE");
        _approve(owner, spender, value);
    }
}
// File: interfaces/IMindchainswapPair.sol


pragma solidity >=0.5.0;

interface IMindchainswapPair {
    event Approval(address indexed owner, address indexed spender, uint256 value);
    event Transfer(address indexed from, address indexed to, uint256 value);

    function name() external pure returns (string memory);

    function symbol() external pure returns (string memory);

    function decimals() external pure returns (uint8);

    function totalSupply() external view returns (uint256);

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

    function allowance(address owner, address spender) external view returns (uint256);

    function approve(address spender, uint256 value) external returns (bool);

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

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

    function DOMAIN_SEPARATOR() external view returns (bytes32);

    function PERMIT_TYPEHASH() external pure returns (bytes32);

    function nonces(address owner) external view returns (uint256);

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    event Mint(address indexed sender, uint256 amount0, uint256 amount1);
    event Burn(address indexed sender, uint256 amount0, uint256 amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint256 amount0In,
        uint256 amount1In,
        uint256 amount0Out,
        uint256 amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint256);

    function factory() external view returns (address);

    function token0() external view returns (address);

    function token1() external view returns (address);

    function getReserves()
        external
        view
        returns (
            uint112 reserve0,
            uint112 reserve1,
            uint32 blockTimestampLast
        );

    function price0CumulativeLast() external view returns (uint256);

    function price1CumulativeLast() external view returns (uint256);

    function kLast() external view returns (uint256);

    function mint(address to) external returns (uint256 liquidity);

    function burn(address to) external returns (uint256 amount0, uint256 amount1);

    function swap(
        uint256 amount0Out,
        uint256 amount1Out,
        address to,
        bytes calldata data
    ) external;

    function skim(address to) external;

    function sync() external;

    function initialize(address, address) external;
}
// File: interfaces/IMindchainswapFactory.sol


pragma solidity >=0.5.0;

interface IMindchainswapFactory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint256);

    function feeTo() external view returns (address);

    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);

    function allPairs(uint256) external view returns (address pair);

    function allPairsLength() external view returns (uint256);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;

    function setFeeToSetter(address) external;

    function INIT_CODE_PAIR_HASH() external view returns (bytes32);
}
// File: MindchainswapPair.sol


pragma solidity =0.5.16;


contract MindchainswapPair is IMindchainswapPair, MindchainswapERC20 {
    using SafeMath  for uint;
    using UQ112x112 for uint224;

    uint public constant MINIMUM_LIQUIDITY = 10**3;
    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

    address public factory;
    address public token0;
    address public token1;

    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves

    uint public price0CumulativeLast;
    uint public price1CumulativeLast;
    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

    uint private unlocked = 1;
    modifier lock() {
        require(unlocked == 1, 'Mindchainswap: LOCKED');
        unlocked = 0;
        _;
        unlocked = 1;
    }

    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
        _reserve0 = reserve0;
        _reserve1 = reserve1;
        _blockTimestampLast = blockTimestampLast;
    }

    function _safeTransfer(address token, address to, uint value) private {
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'Mindchainswap: TRANSFER_FAILED');
    }

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    constructor() public {
        factory = msg.sender;
    }

    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
        require(msg.sender == factory, 'Mindchainswap: FORBIDDEN'); // sufficient check
        token0 = _token0;
        token1 = _token1;
    }

    // update reserves and, on the first call per block, price accumulators
    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'Mindchainswap: OVERFLOW');
        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
            // * never overflows, and + overflow is desired
            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
        }
        reserve0 = uint112(balance0);
        reserve1 = uint112(balance1);
        blockTimestampLast = blockTimestamp;
        emit Sync(reserve0, reserve1);
    }

    // if fee is on, mint liquidity equivalent to 8/25 of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
        address feeTo = IMindchainswapFactory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint _kLast = kLast; // gas savings
        if (feeOn) {
            if (_kLast != 0) {
                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
                uint rootKLast = Math.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint numerator = totalSupply.mul(rootK.sub(rootKLast)).mul(8);
                    uint denominator = rootK.mul(17).add(rootKLast.mul(8));
                    uint liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        uint balance0 = IERC20(token0).balanceOf(address(this));
        uint balance1 = IERC20(token1).balanceOf(address(this));
        uint amount0 = balance0.sub(_reserve0);
        uint amount1 = balance1.sub(_reserve1);

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        if (_totalSupply == 0) {
            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
        } else {
            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
        }
        require(liquidity > 0, 'Mindchainswap: INSUFFICIENT_LIQUIDITY_MINTED');
        _mint(to, liquidity);

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Mint(msg.sender, amount0, amount1);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function burn(address to) external lock returns (uint amount0, uint amount1) {
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        address _token0 = token0;                                // gas savings
        address _token1 = token1;                                // gas savings
        uint balance0 = IERC20(_token0).balanceOf(address(this));
        uint balance1 = IERC20(_token1).balanceOf(address(this));
        uint liquidity = balanceOf[address(this)];

        bool feeOn = _mintFee(_reserve0, _reserve1);
        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
        require(amount0 > 0 && amount1 > 0, 'Mindchainswap: INSUFFICIENT_LIQUIDITY_BURNED');
        _burn(address(this), liquidity);
        _safeTransfer(_token0, to, amount0);
        _safeTransfer(_token1, to, amount1);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));

        _update(balance0, balance1, _reserve0, _reserve1);
        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
        emit Burn(msg.sender, amount0, amount1, to);
    }

    // this low-level function should be called from a contract which performs important safety checks
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
        require(amount0Out > 0 || amount1Out > 0, 'Mindchainswap: INSUFFICIENT_OUTPUT_AMOUNT');
        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'Mindchainswap: INSUFFICIENT_LIQUIDITY');

        uint balance0;
        uint balance1;
        { // scope for _token{0,1}, avoids stack too deep errors
        address _token0 = token0;
        address _token1 = token1;
        require(to != _token0 && to != _token1, 'Mindchainswap: INVALID_TO');
        if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
        if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
        if (data.length > 0) IMindchainswapCallee(to).mindCall(msg.sender, amount0Out, amount1Out, data);
        balance0 = IERC20(_token0).balanceOf(address(this));
        balance1 = IERC20(_token1).balanceOf(address(this));
        }
        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
        require(amount0In > 0 || amount1In > 0, 'Mindchainswap: INSUFFICIENT_INPUT_AMOUNT');
        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = (balance0.mul(10000).sub(amount0In.mul(25)));
        uint balance1Adjusted = (balance1.mul(10000).sub(amount1In.mul(25)));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(10000**2), 'Mindchainswap: K');
        }

        _update(balance0, balance1, _reserve0, _reserve1);
        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
    }

    // force balances to match reserves
    function skim(address to) external lock {
        address _token0 = token0; // gas savings
        address _token1 = token1; // gas savings
        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
    }

    // force reserves to match balances
    function sync() external lock {
        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
    }
}
// File: MindchainswapFactory.sol


pragma solidity =0.5.16;


contract MindchainswapFactory is IMindchainswapFactory {
    bytes32 public constant INIT_CODE_PAIR_HASH = keccak256(abi.encodePacked(type(MindchainswapPair).creationCode));

    address public feeTo;
    address public feeToSetter;

    mapping(address => mapping(address => address)) public getPair;
    address[] public allPairs;

    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    constructor(address _feeToSetter) public {
        feeToSetter = _feeToSetter;
    }

    function allPairsLength() external view returns (uint) {
        return allPairs.length;
    }

    function createPair(address tokenA, address tokenB) external returns (address pair) {
        require(tokenA != tokenB, 'Mindchainswap: IDENTICAL_ADDRESSES');
        (address token0, address token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
        require(token0 != address(0), 'Mindchainswap: ZERO_ADDRESS');
        require(getPair[token0][token1] == address(0), 'Mindchainswap: PAIR_EXISTS'); // single check is sufficient
        bytes memory bytecode = type(MindchainswapPair).creationCode;
        bytes32 salt = keccak256(abi.encodePacked(token0, token1));
        assembly {
            pair := create2(0, add(bytecode, 32), mload(bytecode), salt)
        }
        IMindchainswapPair(pair).initialize(token0, token1);
        getPair[token0][token1] = pair;
        getPair[token1][token0] = pair; // populate mapping in the reverse direction
        allPairs.push(pair);
        emit PairCreated(token0, token1, pair, allPairs.length);
    }

    function setFeeTo(address _feeTo) external {
        require(msg.sender == feeToSetter, 'Mindchainswap: FORBIDDEN');
        feeTo = _feeTo;
    }

    function setFeeToSetter(address _feeToSetter) external {
        require(msg.sender == feeToSetter, 'Mindchainswap: FORBIDDEN');
        feeToSetter = _feeToSetter;
    }
}

	// File: interfaces/IMindchainswapCallee.sol


	pragma solidity >=0.5.0;

	interface IMindchainswapCallee {
	function mindCall(
	address sender,
	uint256 amount0,
	uint256 amount1,
	bytes calldata data
	) external;
	}
	// File: interfaces/IERC20.sol


	pragma solidity >=0.5.0;

	interface IERC20 {
	event Approval(address indexed owner, address indexed spender, uint256 value);
	event Transfer(address indexed from, address indexed to, uint256 value);

	function name() external view returns (string memory);

	function symbol() external view returns (string memory);

	function decimals() external view returns (uint8);

	function totalSupply() external view returns (uint256);

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

	function allowance(address owner, address spender) external view returns (uint256);

	function approve(address spender, uint256 value) external returns (bool);

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

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

	// File: libraries/UQ112x112.sol


	pragma solidity =0.5.16;

	// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))

	// range: [0, 2**112 - 1]
	// resolution: 1 / 2**112

	library UQ112x112 {
	uint224 constant Q112 = 2**112;

	// encode a uint112 as a UQ112x112
	function encode(uint112 y) internal pure returns (uint224 z) {
	z = uint224(y) * Q112; // never overflows
	}

	// divide a UQ112x112 by a uint112, returning a UQ112x112
	function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
	z = x / uint224(y);
	}
	}

	// File: libraries/Math.sol


	pragma solidity =0.5.16;

	// a library for performing various math operations

	library Math {
	function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
	z = x < y ? x : y;
	}

	// babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
	function sqrt(uint256 y) internal pure returns (uint256 z) {
	if (y > 3) {
	z = y;
	uint256 x = y / 2 + 1;
	while (x < z) {
	z = x;
	x = (y / x + x) / 2;
	}
	} else if (y != 0) {
	z = 1;
	}
	}
	}

	// File: libraries/SafeMath.sol


	pragma solidity >=0.5.0 <0.7.0;

	// a library for performing overflow-safe math, courtesy of DappHub (https://github.com/dapphub/ds-math)

	library SafeMath {
	function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
	require((z = x + y) >= x, "ds-math-add-overflow");
	}

	function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
	require((z = x - y) <= x, "ds-math-sub-underflow");
	}

	function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
	require(y == 0 \|\| (z = x * y) / y == x, "ds-math-mul-overflow");
	}
	}

	// File: interfaces/IMindchainswapERC20.sol


	pragma solidity >=0.5.0;

	interface IMindchainswapERC20 {
	event Approval(address indexed owner, address indexed spender, uint256 value);
	event Transfer(address indexed from, address indexed to, uint256 value);

	function name() external pure returns (string memory);

	function symbol() external pure returns (string memory);

	function decimals() external pure returns (uint8);

	function totalSupply() external view returns (uint256);

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

	function allowance(address owner, address spender) external view returns (uint256);

	function approve(address spender, uint256 value) external returns (bool);

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

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

	function DOMAIN_SEPARATOR() external view returns (bytes32);

	function PERMIT_TYPEHASH() external pure returns (bytes32);

	function nonces(address owner) external view returns (uint256);

	function permit(
	address owner,
	address spender,
	uint256 value,
	uint256 deadline,
	uint8 v,
	bytes32 r,
	bytes32 s
	) external;
	}
	// File: MindchainswapERC20.sol


	pragma solidity =0.5.16;



	contract MindchainswapERC20 is IMindchainswapERC20 {
	using SafeMath for uint256;

	string public constant name = "Mindchainswap LPs";
	string public constant symbol = "MIND-LP";
	uint8 public constant decimals = 18;
	uint256 public totalSupply;
	mapping(address => uint256) public balanceOf;
	mapping(address => mapping(address => uint256)) public allowance;

	bytes32 public DOMAIN_SEPARATOR;
	// keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
	bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
	mapping(address => uint256) public nonces;

	event Approval(address indexed owner, address indexed spender, uint256 value);
	event Transfer(address indexed from, address indexed to, uint256 value);

	constructor() public {
	uint256 chainId;
	assembly {
	chainId := chainid
	}
	DOMAIN_SEPARATOR = keccak256(
	abi.encode(
	keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
	keccak256(bytes(name)),
	keccak256(bytes("1")),
	chainId,
	address(this)
	)
	);
	}

	function _mint(address to, uint256 value) internal {
	totalSupply = totalSupply.add(value);
	balanceOf[to] = balanceOf[to].add(value);
	emit Transfer(address(0), to, value);
	}

	function _burn(address from, uint256 value) internal {
	balanceOf[from] = balanceOf[from].sub(value);
	totalSupply = totalSupply.sub(value);
	emit Transfer(from, address(0), value);
	}

	function _approve(
	address owner,
	address spender,
	uint256 value
	) private {
	allowance[owner][spender] = value;
	emit Approval(owner, spender, value);
	}

	function _transfer(
	address from,
	address to,
	uint256 value
	) private {
	balanceOf[from] = balanceOf[from].sub(value);
	balanceOf[to] = balanceOf[to].add(value);
	emit Transfer(from, to, value);
	}

	function approve(address spender, uint256 value) external returns (bool) {
	_approve(msg.sender, spender, value);
	return true;
	}

	function transfer(address to, uint256 value) external returns (bool) {
	_transfer(msg.sender, to, value);
	return true;
	}

	function transferFrom(
	address from,
	address to,
	uint256 value
	) external returns (bool) {
	if (allowance[from][msg.sender] != uint256(-1)) {
	allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
	}
	_transfer(from, to, value);
	return true;
	}

	function permit(
	address owner,
	address spender,
	uint256 value,
	uint256 deadline,
	uint8 v,
	bytes32 r,
	bytes32 s
	) external {
	require(deadline >= block.timestamp, "Mindchainswap: EXPIRED");
	bytes32 digest = keccak256(
	abi.encodePacked(
	"\x19\x01",
	DOMAIN_SEPARATOR,
	keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
	)
	);
	address recoveredAddress = ecrecover(digest, v, r, s);
	require(recoveredAddress != address(0) && recoveredAddress == owner, "Mindchainswap: INVALID_SIGNATURE");
	_approve(owner, spender, value);
	}
	}
	// File: interfaces/IMindchainswapPair.sol


	pragma solidity >=0.5.0;

	interface IMindchainswapPair {
	event Approval(address indexed owner, address indexed spender, uint256 value);
	event Transfer(address indexed from, address indexed to, uint256 value);

	function name() external pure returns (string memory);

	function symbol() external pure returns (string memory);

	function decimals() external pure returns (uint8);

	function totalSupply() external view returns (uint256);

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

	function allowance(address owner, address spender) external view returns (uint256);

	function approve(address spender, uint256 value) external returns (bool);

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

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

	function DOMAIN_SEPARATOR() external view returns (bytes32);

	function PERMIT_TYPEHASH() external pure returns (bytes32);

	function nonces(address owner) external view returns (uint256);

	function permit(
	address owner,
	address spender,
	uint256 value,
	uint256 deadline,
	uint8 v,
	bytes32 r,
	bytes32 s
	) external;

	event Mint(address indexed sender, uint256 amount0, uint256 amount1);
	event Burn(address indexed sender, uint256 amount0, uint256 amount1, address indexed to);
	event Swap(
	address indexed sender,
	uint256 amount0In,
	uint256 amount1In,
	uint256 amount0Out,
	uint256 amount1Out,
	address indexed to
	);
	event Sync(uint112 reserve0, uint112 reserve1);

	function MINIMUM_LIQUIDITY() external pure returns (uint256);

	function factory() external view returns (address);

	function token0() external view returns (address);

	function token1() external view returns (address);

	function getReserves()
	external
	view
	returns (
	uint112 reserve0,
	uint112 reserve1,
	uint32 blockTimestampLast
	);

	function price0CumulativeLast() external view returns (uint256);

	function price1CumulativeLast() external view returns (uint256);

	function kLast() external view returns (uint256);

	function mint(address to) external returns (uint256 liquidity);

	function burn(address to) external returns (uint256 amount0, uint256 amount1);

	function swap(
	uint256 amount0Out,
	uint256 amount1Out,
	address to,
	bytes calldata data
	) external;

	function skim(address to) external;

	function sync() external;

	function initialize(address, address) external;
	}
	// File: interfaces/IMindchainswapFactory.sol


	pragma solidity >=0.5.0;

	interface IMindchainswapFactory {
	event PairCreated(address indexed token0, address indexed token1, address pair, uint256);

	function feeTo() external view returns (address);

	function feeToSetter() external view returns (address);

	function getPair(address tokenA, address tokenB) external view returns (address pair);

	function allPairs(uint256) external view returns (address pair);

	function allPairsLength() external view returns (uint256);

	function createPair(address tokenA, address tokenB) external returns (address pair);

	function setFeeTo(address) external;

	function setFeeToSetter(address) external;

	function INIT_CODE_PAIR_HASH() external view returns (bytes32);
	}
	// File: MindchainswapPair.sol


	pragma solidity =0.5.16;








	contract MindchainswapPair is IMindchainswapPair, MindchainswapERC20 {
	using SafeMath for uint;
	using UQ112x112 for uint224;

	uint public constant MINIMUM_LIQUIDITY = 10**3;
	bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));

	address public factory;
	address public token0;
	address public token1;

	uint112 private reserve0; // uses single storage slot, accessible via getReserves
	uint112 private reserve1; // uses single storage slot, accessible via getReserves
	uint32 private blockTimestampLast; // uses single storage slot, accessible via getReserves

	uint public price0CumulativeLast;
	uint public price1CumulativeLast;
	uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event

	uint private unlocked = 1;
	modifier lock() {
	require(unlocked == 1, 'Mindchainswap: LOCKED');
	unlocked = 0;
	_;
	unlocked = 1;
	}

	function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
	_reserve0 = reserve0;
	_reserve1 = reserve1;
	_blockTimestampLast = blockTimestampLast;
	}

	function _safeTransfer(address token, address to, uint value) private {
	(bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
	require(success && (data.length == 0 \|\| abi.decode(data, (bool))), 'Mindchainswap: TRANSFER_FAILED');
	}

	event Mint(address indexed sender, uint amount0, uint amount1);
	event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
	event Swap(
	address indexed sender,
	uint amount0In,
	uint amount1In,
	uint amount0Out,
	uint amount1Out,
	address indexed to
	);
	event Sync(uint112 reserve0, uint112 reserve1);

	constructor() public {
	factory = msg.sender;
	}

	// called once by the factory at time of deployment
	function initialize(address _token0, address _token1) external {
	require(msg.sender == factory, 'Mindchainswap: FORBIDDEN'); // sufficient check
	token0 = _token0;
	token1 = _token1;
	}

	// update reserves and, on the first call per block, price accumulators
	function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
	require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'Mindchainswap: OVERFLOW');
	uint32 blockTimestamp = uint32(block.timestamp % 2**32);
	uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
	if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
	// * never overflows, and + overflow is desired
	price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
	price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
	}
	reserve0 = uint112(balance0);
	reserve1 = uint112(balance1);
	blockTimestampLast = blockTimestamp;
	emit Sync(reserve0, reserve1);
	}

	// if fee is on, mint liquidity equivalent to 8/25 of the growth in sqrt(k)
	function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
	address feeTo = IMindchainswapFactory(factory).feeTo();
	feeOn = feeTo != address(0);
	uint _kLast = kLast; // gas savings
	if (feeOn) {
	if (_kLast != 0) {
	uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
	uint rootKLast = Math.sqrt(_kLast);
	if (rootK > rootKLast) {
	uint numerator = totalSupply.mul(rootK.sub(rootKLast)).mul(8);
	uint denominator = rootK.mul(17).add(rootKLast.mul(8));
	uint liquidity = numerator / denominator;
	if (liquidity > 0) _mint(feeTo, liquidity);
	}
	}
	} else if (_kLast != 0) {
	kLast = 0;
	}
	}

	// this low-level function should be called from a contract which performs important safety checks
	function mint(address to) external lock returns (uint liquidity) {
	(uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
	uint balance0 = IERC20(token0).balanceOf(address(this));
	uint balance1 = IERC20(token1).balanceOf(address(this));
	uint amount0 = balance0.sub(_reserve0);
	uint amount1 = balance1.sub(_reserve1);

	bool feeOn = _mintFee(_reserve0, _reserve1);
	uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
	if (_totalSupply == 0) {
	liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
	_mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
	} else {
	liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
	}
	require(liquidity > 0, 'Mindchainswap: INSUFFICIENT_LIQUIDITY_MINTED');
	_mint(to, liquidity);

	_update(balance0, balance1, _reserve0, _reserve1);
	if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
	emit Mint(msg.sender, amount0, amount1);
	}

	// this low-level function should be called from a contract which performs important safety checks
	function burn(address to) external lock returns (uint amount0, uint amount1) {
	(uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
	address _token0 = token0; // gas savings
	address _token1 = token1; // gas savings
	uint balance0 = IERC20(_token0).balanceOf(address(this));
	uint balance1 = IERC20(_token1).balanceOf(address(this));
	uint liquidity = balanceOf[address(this)];

	bool feeOn = _mintFee(_reserve0, _reserve1);
	uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
	amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
	amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
	require(amount0 > 0 && amount1 > 0, 'Mindchainswap: INSUFFICIENT_LIQUIDITY_BURNED');
	_burn(address(this), liquidity);
	_safeTransfer(_token0, to, amount0);
	_safeTransfer(_token1, to, amount1);
	balance0 = IERC20(_token0).balanceOf(address(this));
	balance1 = IERC20(_token1).balanceOf(address(this));

	_update(balance0, balance1, _reserve0, _reserve1);
	if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
	emit Burn(msg.sender, amount0, amount1, to);
	}

	// this low-level function should be called from a contract which performs important safety checks
	function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
	require(amount0Out > 0 \|\| amount1Out > 0, 'Mindchainswap: INSUFFICIENT_OUTPUT_AMOUNT');
	(uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
	require(amount0Out < _reserve0 && amount1Out < _reserve1, 'Mindchainswap: INSUFFICIENT_LIQUIDITY');

	uint balance0;
	uint balance1;
	{ // scope for _token{0,1}, avoids stack too deep errors
	address _token0 = token0;
	address _token1 = token1;
	require(to != _token0 && to != _token1, 'Mindchainswap: INVALID_TO');
	if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
	if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
	if (data.length > 0) IMindchainswapCallee(to).mindCall(msg.sender, amount0Out, amount1Out, data);
	balance0 = IERC20(_token0).balanceOf(address(this));
	balance1 = IERC20(_token1).balanceOf(address(this));
	}
	uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
	uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
	require(amount0In > 0 \|\| amount1In > 0, 'Mindchainswap: INSUFFICIENT_INPUT_AMOUNT');
	{ // scope for reserve{0,1}Adjusted, avoids stack too deep errors
	uint balance0Adjusted = (balance0.mul(10000).sub(amount0In.mul(25)));
	uint balance1Adjusted = (balance1.mul(10000).sub(amount1In.mul(25)));
	require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(10000**2), 'Mindchainswap: K');
	}

	_update(balance0, balance1, _reserve0, _reserve1);
	emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
	}

	// force balances to match reserves
	function skim(address to) external lock {
	address _token0 = token0; // gas savings
	address _token1 = token1; // gas savings
	_safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
	_safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
	}

	// force reserves to match balances
	function sync() external lock {
	_update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
	}
	}
	// File: MindchainswapFactory.sol


	pragma solidity =0.5.16;



	contract MindchainswapFactory is IMindchainswapFactory {
	bytes32 public constant INIT_CODE_PAIR_HASH = keccak256(abi.encodePacked(type(MindchainswapPair).creationCode));

	address public feeTo;
	address public feeToSetter;

	mapping(address => mapping(address => address)) public getPair;
	address[] public allPairs;

	event PairCreated(address indexed token0, address indexed token1, address pair, uint);

	constructor(address _feeToSetter) public {
	feeToSetter = _feeToSetter;
	}

	function allPairsLength() external view returns (uint) {
	return allPairs.length;
	}

	function createPair(address tokenA, address tokenB) external returns (address pair) {
	require(tokenA != tokenB, 'Mindchainswap: IDENTICAL_ADDRESSES');
	(address token0, address token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
	require(token0 != address(0), 'Mindchainswap: ZERO_ADDRESS');
	require(getPair[token0][token1] == address(0), 'Mindchainswap: PAIR_EXISTS'); // single check is sufficient
	bytes memory bytecode = type(MindchainswapPair).creationCode;
	bytes32 salt = keccak256(abi.encodePacked(token0, token1));
	assembly {
	pair := create2(0, add(bytecode, 32), mload(bytecode), salt)
	}
	IMindchainswapPair(pair).initialize(token0, token1);
	getPair[token0][token1] = pair;
	getPair[token1][token0] = pair; // populate mapping in the reverse direction
	allPairs.push(pair);
	emit PairCreated(token0, token1, pair, allPairs.length);
	}

	function setFeeTo(address _feeTo) external {
	require(msg.sender == feeToSetter, 'Mindchainswap: FORBIDDEN');
	feeTo = _feeTo;
	}

	function setFeeToSetter(address _feeToSetter) external {
	require(msg.sender == feeToSetter, 'Mindchainswap: FORBIDDEN');
	feeToSetter = _feeToSetter;
	}
	}