creation_sourcecode: // SPDX-License-Identifier: MIT
  pragma solidity >=0.8.0 <0.9.0;
  
  interface ILiquidXv2Pair {
    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);
  
    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
  
    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);
  
    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
  
    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);
  
    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;
  
    function initialize(address, address) external;
  }
  
  interface ILiquidXv2ERC20 {
    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);
  
    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
  
    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);
  
    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
  }
  
  library SafeMath {
    function add(uint x, uint y) internal pure returns (uint z) {
      require((z = x + y) >= x, 'ds-math-add-overflow');
    }
  
    function sub(uint x, uint y) internal pure returns (uint z) {
      require((z = x - y) <= x, 'ds-math-sub-underflow');
    }
  
    function mul(uint x, uint y) internal pure returns (uint z) {
      require(y == 0 || (z = x * y) / y == x, 'ds-math-mul-overflow');
    }
  }
  
  contract LiquidXv2ERC20 is ILiquidXv2ERC20 {
    using SafeMath for uint;
  
    string public constant name = 'JFX V2';
    string public constant symbol = 'JFX-V2';
    uint8 public constant decimals = 18;
    uint  public totalSupply;
    mapping(address => uint) public balanceOf;
    mapping(address => mapping(address => uint)) public allowance;
  
    bytes32 public DOMAIN_SEPARATOR;
    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
    mapping(address => uint) public nonces;
  
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);
  
    constructor() {
      DOMAIN_SEPARATOR = keccak256(
        abi.encode(
          keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
          keccak256(bytes(name)),
          keccak256(bytes('1')),
          3501,
          address(this)
        )
      );
    }
  
    function _mint(address to, uint value) internal {
      totalSupply = totalSupply.add(value);
      balanceOf[to] = balanceOf[to].add(value);
      emit Transfer(address(0), to, value);
    }
  
    function _burn(address from, uint value) internal {
      balanceOf[from] = balanceOf[from].sub(value);
      totalSupply = totalSupply.sub(value);
      emit Transfer(from, address(0), value);
    }
  
    function _approve(address owner, address spender, uint value) private {
      allowance[owner][spender] = value;
      emit Approval(owner, spender, value);
    }
  
    function _transfer(address from, address to, uint value) private {
      balanceOf[from] = balanceOf[from].sub(value);
      balanceOf[to] = balanceOf[to].add(value);
      emit Transfer(from, to, value);
    }
  
    function approve(address spender, uint value) external returns (bool) {
      _approve(msg.sender, spender, value);
      return true;
    }
  
    function transfer(address to, uint value) external returns (bool) {
      _transfer(msg.sender, to, value);
      return true;
    }
  
    function transferFrom(address from, address to, uint value) external returns (bool) {
      if (allowance[from][msg.sender] != type(uint256).max) {
        allowance[from][msg.sender] = allowance[from][msg.sender].sub(value);
      }
      _transfer(from, to, value);
      return true;
    }
  
    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
      require(deadline >= block.timestamp, 'LiquidXv2: 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, 'LiquidXv2: INVALID_SIGNATURE');
      _approve(owner, spender, value);
    }
  }
  
  library Math {
    function min(uint x, uint y) internal pure returns (uint z) {
      z = x < y ? x : y;
    }
  
    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
      if (y > 3) {
        z = y;
        uint x = y / 2 + 1;
        while (x < z) {
          z = x;
          x = (y / x + x) / 2;
        }
      } else if (y != 0) {
        z = 1;
      }
    }
  }
  
  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);
    }
  }
  
  interface IERC20 {
    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function decimals() external view returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);
  
    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);
  }
  
  interface ILiquidXv2Factory {
    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);
  
    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);
  
    function createPair(address tokenA, address tokenB) external returns (address pair);
  
    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
  }
  
  interface ILiquidXv2Callee {
    function LiquidXv2Call(address sender, uint amount0, uint amount1, bytes calldata data) external;
  }
  
  contract LiquidXv2Pair is LiquidXv2ERC20 {
    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, 'LiquidXv2: 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))), 'LiquidXv2: 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() {
      factory = msg.sender;
    }
  
    // called once by the factory at time of deployment
    function initialize(address _token0, address _token1) external {
      require(msg.sender == factory, 'LiquidXv2: 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 <= type(uint112).max && balance1 <= type(uint112).max, 'LiquidXv2: OVERFLOW');
      uint32 blockTimestamp = uint32(block.timestamp % 2**32);
      uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
      if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
        // * never overflows, and + overflow is desired
        price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
        price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
      }
      reserve0 = uint112(balance0);
      reserve1 = uint112(balance1);
      blockTimestampLast = blockTimestamp;
      emit Sync(reserve0, reserve1);
    }
  
    // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
      address feeTo = ILiquidXv2Factory(factory).feeTo();
      feeOn = feeTo != address(0);
      uint _kLast = kLast; // gas savings
      if (feeOn) {
        if (_kLast != 0) {
          uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
          uint rootKLast = Math.sqrt(_kLast);
          if (rootK > rootKLast) {
            uint numerator = totalSupply.mul(rootK.sub(rootKLast));
            uint denominator = rootK.mul(5).add(rootKLast);
            uint liquidity = numerator / denominator;
            if (liquidity > 0) _mint(feeTo, liquidity);
          }
        }
      } else if (_kLast != 0) {
        kLast = 0;
      }
    }
  
    // this low-level function should be called from a contract which performs important safety checks
    function mint(address to) external lock returns (uint liquidity) {
      (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
      uint balance0 = IERC20(token0).balanceOf(address(this));
      uint balance1 = IERC20(token1).balanceOf(address(this));
      uint amount0 = balance0.sub(_reserve0);
      uint amount1 = balance1.sub(_reserve1);
  
      bool feeOn = _mintFee(_reserve0, _reserve1);
      uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
      if (_totalSupply == 0) {
        liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
        _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
      } else {
        liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
      }
      require(liquidity > 0, 'LiquidXv2: 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, 'LiquidXv2: 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, 'LiquidXv2: INSUFFICIENT_OUTPUT_AMOUNT');
      (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
      require(amount0Out < _reserve0 && amount1Out < _reserve1, 'LiquidXv2: 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, 'LiquidXv2: 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) ILiquidXv2Callee(to).LiquidXv2Call(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, 'LiquidXv2: INSUFFICIENT_INPUT_AMOUNT');
      { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
        uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
        uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
        require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'LiquidXv2: 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);
    }
  }