Uniswap-v2 Contract Walk-Through

1pragma solidity =0.5.16;
2
3import './interfaces/IUniswapV2Pair.sol';
4import './UniswapV2ERC20.sol';
5import './libraries/Math.sol';
6import './libraries/UQ112x112.sol';
7import './interfaces/IERC20.sol';
8import './interfaces/IUniswapV2Factory.sol';
9import './interfaces/IUniswapV2Callee.sol';
10
Εμφάνιση όλων
 Αντιγραφή

1contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
2
 Αντιγραφή

1    using SafeMath  for uint;
2
 Αντιγραφή

1    using UQ112x112 for uint224;
2
 Αντιγραφή

1    uint public constant MINIMUM_LIQUIDITY = 10**3;
2
 Αντιγραφή

1    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));
2
 Αντιγραφή

1    address public factory;
2
 Αντιγραφή

1    address public token0;
2    address public token1;
3
 Αντιγραφή

1    uint112 private reserve0;           // uses single storage slot, accessible via getReserves
2    uint112 private reserve1;           // uses single storage slot, accessible via getReserves
3
 Αντιγραφή

1    uint32  private blockTimestampLast; // uses single storage slot, accessible via getReserves
2
 Αντιγραφή

1    uint public price0CumulativeLast;
2    uint public price1CumulativeLast;
3
 Αντιγραφή

1    uint public kLast; // reserve0 * reserve1, as of immediately after the most recent liquidity event
2
 Αντιγραφή

1    uint private unlocked = 1;
2
 Αντιγραφή

1    modifier lock() {
2
 Αντιγραφή

1        require(unlocked == 1, 'UniswapV2: LOCKED');
2        unlocked = 0;
3
 Αντιγραφή

1        _;
2
 Αντιγραφή

1        unlocked = 1;
2    }
3
 Αντιγραφή

1    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {
2        _reserve0 = reserve0;
3        _reserve1 = reserve1;
4        _blockTimestampLast = blockTimestampLast;
5    }
6
 Αντιγραφή

1    function _safeTransfer(address token, address to, uint value) private {
2        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
3
 Αντιγραφή

1        require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');
2    }
3
 Αντιγραφή

1    event Mint(address indexed sender, uint amount0, uint amount1);
2    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
3
 Αντιγραφή

1    event Swap(
2        address indexed sender,
3        uint amount0In,
4        uint amount1In,
5        uint amount0Out,
6        uint amount1Out,
7        address indexed to
8    );
9
 Αντιγραφή

1    event Sync(uint112 reserve0, uint112 reserve1);
2
 Αντιγραφή

1    constructor() public {
2        factory = msg.sender;
3    }
4
 Αντιγραφή

1    // called once by the factory at time of deployment
2    function initialize(address _token0, address _token1) external {
3        require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // sufficient check
4        token0 = _token0;
5        token1 = _token1;
6    }
7
 Αντιγραφή

1    // update reserves and, on the first call per block, price accumulators
2    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
3
 Αντιγραφή

1        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
2
 Αντιγραφή

1        uint32 blockTimestamp = uint32(block.timestamp % 2**32);
2        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // overflow is desired
3        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
4
 Αντιγραφή

1            // * never overflows, and + overflow is desired
2            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;
3            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;
4        }
5
 Αντιγραφή

1        reserve0 = uint112(balance0);
2        reserve1 = uint112(balance1);
3        blockTimestampLast = blockTimestamp;
4        emit Sync(reserve0, reserve1);
5    }
6
 Αντιγραφή

1    // if fee is on, mint liquidity equivalent to 1/6th of the growth in sqrt(k)
2    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
3
 Αντιγραφή

1        address feeTo = IUniswapV2Factory(factory).feeTo();
2        feeOn = feeTo != address(0);
3
 Αντιγραφή

1        uint _kLast = kLast; // gas savings
2
 Αντιγραφή

1        if (feeOn) {
2            if (_kLast != 0) {
3
 Αντιγραφή

1                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));
2                uint rootKLast = Math.sqrt(_kLast);
3                if (rootK > rootKLast) {
4
 Αντιγραφή

1                    uint numerator = totalSupply.mul(rootK.sub(rootKLast));
2                    uint denominator = rootK.mul(5).add(rootKLast);
3                    uint liquidity = numerator / denominator;
4
 Αντιγραφή

1                    if (liquidity > 0) _mint(feeTo, liquidity);
2                }
3            }
4
 Αντιγραφή

1        } else if (_kLast != 0) {
2            kLast = 0;
3        }
4    }
5
 Αντιγραφή

1    // this low-level function should be called from a contract which performs important safety checks
2    function mint(address to) external lock returns (uint liquidity) {
3
 Αντιγραφή

1        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
2
 Αντιγραφή

1        uint balance0 = IERC20(token0).balanceOf(address(this));
2        uint balance1 = IERC20(token1).balanceOf(address(this));
3        uint amount0 = balance0.sub(_reserve0);
4        uint amount1 = balance1.sub(_reserve1);
5
 Αντιγραφή

1        bool feeOn = _mintFee(_reserve0, _reserve1);
2
 Αντιγραφή

1        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
2        if (_totalSupply == 0) {
3            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);
4           _mint(address(0), MINIMUM_LIQUIDITY); // permanently lock the first MINIMUM_LIQUIDITY tokens
5
 Αντιγραφή

1        } else {
2            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
3
 Αντιγραφή

1        }
2        require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');
3        _mint(to, liquidity);
4
 Αντιγραφή

1
2        _update(balance0, balance1, _reserve0, _reserve1);
3        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
4        emit Mint(msg.sender, amount0, amount1);
5    }
6
 Αντιγραφή

1    // this low-level function should be called from a contract which performs important safety checks
2    function burn(address to) external lock returns (uint amount0, uint amount1) {
3
 Αντιγραφή

1        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
2        address _token0 = token0;                                // gas savings
3        address _token1 = token1;                                // gas savings
4        uint balance0 = IERC20(_token0).balanceOf(address(this));
5        uint balance1 = IERC20(_token1).balanceOf(address(this));
6        uint liquidity = balanceOf[address(this)];
7
 Αντιγραφή

1        bool feeOn = _mintFee(_reserve0, _reserve1);
2        uint _totalSupply = totalSupply; // gas savings, must be defined here since totalSupply can update in _mintFee
3        amount0 = liquidity.mul(balance0) / _totalSupply; // using balances ensures pro-rata distribution
4        amount1 = liquidity.mul(balance1) / _totalSupply; // using balances ensures pro-rata distribution
5        require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
6
 Αντιγραφή

1        _burn(address(this), liquidity);
2        _safeTransfer(_token0, to, amount0);
3        _safeTransfer(_token1, to, amount1);
4        balance0 = IERC20(_token0).balanceOf(address(this));
5        balance1 = IERC20(_token1).balanceOf(address(this));
6
7        _update(balance0, balance1, _reserve0, _reserve1);
8        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 and reserve1 are up-to-date
9        emit Burn(msg.sender, amount0, amount1, to);
10    }
11
12
Εμφάνιση όλων
 Αντιγραφή

1    // this low-level function should be called from a contract which performs important safety checks
2    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
3
 Αντιγραφή

1        require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');
2        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // gas savings
3        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');
4
5        uint balance0;
6        uint balance1;
7        { // scope for _token{0,1}, avoids stack too deep errors
8
 Αντιγραφή

1            address _token0 = token0;
2            address _token1 = token1;
3            require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');
4            if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // optimistically transfer tokens
5            if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // optimistically transfer tokens
6
 Αντιγραφή

1            if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
2
 Αντιγραφή

1            balance0 = IERC20(_token0).balanceOf(address(this));
2            balance1 = IERC20(_token1).balanceOf(address(this));
3        }
4
 Αντιγραφή

1        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;
2        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;
3        require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');
4        { // scope for reserve{0,1}Adjusted, avoids stack too deep errors
5            uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));
6            uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));
7            require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
8
 Αντιγραφή

1        }
2
3        _update(balance0, balance1, _reserve0, _reserve1);
4        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);
5    }
6
 Αντιγραφή

1    // force balances to match reserves
2    function skim(address to) external lock {
3        address _token0 = token0; // gas savings
4        address _token1 = token1; // gas savings
5        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));
6        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));
7    }
8
9
10
11    // force reserves to match balances
12    function sync() external lock {
13        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);
14    }
15}
16
Εμφάνιση όλων
 Αντιγραφή

1pragma solidity =0.5.16;
2
3import './interfaces/IUniswapV2Factory.sol';
4import './UniswapV2Pair.sol';
5
6contract UniswapV2Factory is IUniswapV2Factory {
7    address public feeTo;
8    address public feeToSetter;
9
 Αντιγραφή

1    mapping(address => mapping(address => address)) public getPair;
2    address[] public allPairs;
3
 Αντιγραφή

1    event PairCreated(address indexed token0, address indexed token1, address pair, uint);
2
 Αντιγραφή

1    constructor(address _feeToSetter) public {
2        feeToSetter = _feeToSetter;
3    }
4
 Αντιγραφή

1    function allPairsLength() external view returns (uint) {
2        return allPairs.length;
3    }
4
 Αντιγραφή

1    function createPair(address tokenA, address tokenB) external returns (address pair) {
2
 Αντιγραφή

1        require(tokenA != tokenB, 'UniswapV2: IDENTICAL_ADDRESSES');
2        (address token0, address token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
3
 Αντιγραφή

1        require(token0 != address(0), 'UniswapV2: ZERO_ADDRESS');
2        require(getPair[token0][token1] == address(0), 'UniswapV2: PAIR_EXISTS'); // single check is sufficient
3
 Αντιγραφή

1        bytes memory bytecode = type(UniswapV2Pair).creationCode;
2
 Αντιγραφή

1        bytes32 salt = keccak256(abi.encodePacked(token0, token1));
2        assembly {
3            pair := create2(0, add(bytecode, 32), mload(bytecode), salt)
4        }
5
 Αντιγραφή

1        IUniswapV2Pair(pair).initialize(token0, token1);
2
 Αντιγραφή

1        getPair[token0][token1] = pair;
2        getPair[token1][token0] = pair; // populate mapping in the reverse direction
3        allPairs.push(pair);
4        emit PairCreated(token0, token1, pair, allPairs.length);
5    }
6
 Αντιγραφή

1    function setFeeTo(address _feeTo) external {
2        require(msg.sender == feeToSetter, 'UniswapV2: FORBIDDEN');
3        feeTo = _feeTo;
4    }
5
6    function setFeeToSetter(address _feeToSetter) external {
7        require(msg.sender == feeToSetter, 'UniswapV2: FORBIDDEN');
8        feeToSetter = _feeToSetter;
9    }
10}
11
Εμφάνιση όλων
 Αντιγραφή

1    bytes32 public DOMAIN_SEPARATOR;
2    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
3    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
4
 Αντιγραφή

1    mapping(address => uint) public nonces;
2
 Αντιγραφή

1    constructor() public {
2        uint chainId;
3        assembly {
4            chainId := chainid
5        }
6
 Αντιγραφή

1        DOMAIN_SEPARATOR = keccak256(
2            abi.encode(
3                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),
4                keccak256(bytes(name)),
5                keccak256(bytes('1')),
6                chainId,
7                address(this)
8            )
9        );
10    }
11
Εμφάνιση όλων
 Αντιγραφή

1    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
2
 Αντιγραφή

1        require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
2
 Αντιγραφή

1        bytes32 digest = keccak256(
2            abi.encodePacked(
3                '\x19\x01',
4                DOMAIN_SEPARATOR,
5                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))
6            )
7        );
8
 Αντιγραφή

1        address recoveredAddress = ecrecover(digest, v, r, s);
2
 Αντιγραφή

1        require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');
2        _approve(owner, spender, value);
3    }
4
5
 Αντιγραφή

1pragma solidity =0.6.6;
2
3import '@uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol';
4import '@uniswap/lib/contracts/libraries/TransferHelper.sol';
5
6import './interfaces/IUniswapV2Router02.sol';
7import './libraries/UniswapV2Library.sol';
8import './libraries/SafeMath.sol';
9import './interfaces/IERC20.sol';
10import './interfaces/IWETH.sol';
11
Εμφάνιση όλων
 Αντιγραφή

1contract UniswapV2Router02 is IUniswapV2Router02 {
2    using SafeMath for uint;
3
4    address public immutable override factory;
5    address public immutable override WETH;
6
 Αντιγραφή

1    modifier ensure(uint deadline) {
2        require(deadline >= block.timestamp, 'UniswapV2Router: EXPIRED');
3        _;
4    }
5
 Αντιγραφή

1    constructor(address _factory, address _WETH) public {
2        factory = _factory;
3        WETH = _WETH;
4    }
5
 Αντιγραφή

1    receive() external payable {
2        assert(msg.sender == WETH); // only accept ETH via fallback from the WETH contract
3    }
4
 Αντιγραφή

1
2    // **** ADD LIQUIDITY ****
3    function _addLiquidity(
4
 Αντιγραφή

1        address tokenA,
2        address tokenB,
3
 Αντιγραφή

1        uint amountADesired,
2        uint amountBDesired,
3
 Αντιγραφή

1        uint amountAMin,
2        uint amountBMin
3
 Αντιγραφή

1    ) internal virtual returns (uint amountA, uint amountB) {
2
 Αντιγραφή

1        // create the pair if it doesn't exist yet
2        if (IUniswapV2Factory(factory).getPair(tokenA, tokenB) == address(0)) {
3            IUniswapV2Factory(factory).createPair(tokenA, tokenB);
4        }
5
 Αντιγραφή

1        (uint reserveA, uint reserveB) = UniswapV2Library.getReserves(factory, tokenA, tokenB);
2
 Αντιγραφή

1        if (reserveA == 0 && reserveB == 0) {
2            (amountA, amountB) = (amountADesired, amountBDesired);
3
 Αντιγραφή

1        } else {
2            uint amountBOptimal = UniswapV2Library.quote(amountADesired, reserveA, reserveB);
3
 Αντιγραφή

1            if (amountBOptimal <= amountBDesired) {
2                require(amountBOptimal >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
3                (amountA, amountB) = (amountADesired, amountBOptimal);
4
 Αντιγραφή

1            } else {
2                uint amountAOptimal = UniswapV2Library.quote(amountBDesired, reserveB, reserveA);
3                assert(amountAOptimal <= amountADesired);
4                require(amountAOptimal >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
5                (amountA, amountB) = (amountAOptimal, amountBDesired);
6
 Αντιγραφή

1            }
2        }
3    }
4
 Αντιγραφή

1    function addLiquidity(
2        address tokenA,
3        address tokenB,
4        uint amountADesired,
5        uint amountBDesired,
6        uint amountAMin,
7        uint amountBMin,
8        address to,
9        uint deadline
10
Εμφάνιση όλων
 Αντιγραφή

1    ) external virtual override ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {
2        (amountA, amountB) = _addLiquidity(tokenA, tokenB, amountADesired, amountBDesired, amountAMin, amountBMin);
3        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
4
 Αντιγραφή

1        TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amountA);
2        TransferHelper.safeTransferFrom(tokenB, msg.sender, pair, amountB);
3
 Αντιγραφή

1        liquidity = IUniswapV2Pair(pair).mint(to);
2    }
3
 Αντιγραφή

1    function addLiquidityETH(
2        address token,
3        uint amountTokenDesired,
4
 Αντιγραφή

1        uint amountTokenMin,
2        uint amountETHMin,
3        address to,
4        uint deadline
5    ) external virtual override payable ensure(deadline) returns (uint amountToken, uint amountETH, uint liquidity) {
6        (amountToken, amountETH) = _addLiquidity(
7            token,
8            WETH,
9            amountTokenDesired,
10            msg.value,
11            amountTokenMin,
12            amountETHMin
13        );
14        address pair = UniswapV2Library.pairFor(factory, token, WETH);
15        TransferHelper.safeTransferFrom(token, msg.sender, pair, amountToken);
16        IWETH(WETH).deposit{value: amountETH}();
17        assert(IWETH(WETH).transfer(pair, amountETH));
18
Εμφάνιση όλων
 Αντιγραφή

1        liquidity = IUniswapV2Pair(pair).mint(to);
2        // refund dust eth, if any
3        if (msg.value > amountETH) TransferHelper.safeTransferETH(msg.sender, msg.value - amountETH);
4    }
5
 Αντιγραφή

1    // **** REMOVE LIQUIDITY ****
2    function removeLiquidity(
3        address tokenA,
4        address tokenB,
5        uint liquidity,
6        uint amountAMin,
7        uint amountBMin,
8        address to,
9        uint deadline
10    ) public virtual override ensure(deadline) returns (uint amountA, uint amountB) {
11
Εμφάνιση όλων
 Αντιγραφή

1        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
2        IUniswapV2Pair(pair).transferFrom(msg.sender, pair, liquidity); // send liquidity to pair
3        (uint amount0, uint amount1) = IUniswapV2Pair(pair).burn(to);
4
 Αντιγραφή

1        (address token0,) = UniswapV2Library.sortTokens(tokenA, tokenB);
2
 Αντιγραφή

1        (amountA, amountB) = tokenA == token0 ? (amount0, amount1) : (amount1, amount0);
2
 Αντιγραφή

1        require(amountA >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
2        require(amountB >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
3    }
4
 Αντιγραφή

1    function removeLiquidityETH(
2        address token,
3        uint liquidity,
4        uint amountTokenMin,
5        uint amountETHMin,
6        address to,
7        uint deadline
8    ) public virtual override ensure(deadline) returns (uint amountToken, uint amountETH) {
9        (amountToken, amountETH) = removeLiquidity(
10            token,
11            WETH,
12            liquidity,
13            amountTokenMin,
14            amountETHMin,
15            address(this),
16            deadline
17        );
18        TransferHelper.safeTransfer(token, to, amountToken);
19        IWETH(WETH).withdraw(amountETH);
20        TransferHelper.safeTransferETH(to, amountETH);
21    }
22
Εμφάνιση όλων
 Αντιγραφή

1    function removeLiquidityWithPermit(
2        address tokenA,
3        address tokenB,
4        uint liquidity,
5        uint amountAMin,
6        uint amountBMin,
7        address to,
8        uint deadline,
9        bool approveMax, uint8 v, bytes32 r, bytes32 s
10    ) external virtual override returns (uint amountA, uint amountB) {
11        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
12        uint value = approveMax ? uint(-1) : liquidity;
13        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
14        (amountA, amountB) = removeLiquidity(tokenA, tokenB, liquidity, amountAMin, amountBMin, to, deadline);
15    }
16
17
18    function removeLiquidityETHWithPermit(
19        address token,
20        uint liquidity,
21        uint amountTokenMin,
22        uint amountETHMin,
23        address to,
24        uint deadline,
25        bool approveMax, uint8 v, bytes32 r, bytes32 s
26    ) external virtual override returns (uint amountToken, uint amountETH) {
27        address pair = UniswapV2Library.pairFor(factory, token, WETH);
28        uint value = approveMax ? uint(-1) : liquidity;
29        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
30        (amountToken, amountETH) = removeLiquidityETH(token, liquidity, amountTokenMin, amountETHMin, to, deadline);
31    }
32
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1
2    // **** REMOVE LIQUIDITY (supporting fee-on-transfer tokens) ****
3    function removeLiquidityETHSupportingFeeOnTransferTokens(
4        address token,
5        uint liquidity,
6        uint amountTokenMin,
7        uint amountETHMin,
8        address to,
9        uint deadline
10    ) public virtual override ensure(deadline) returns (uint amountETH) {
11        (, amountETH) = removeLiquidity(
12            token,
13            WETH,
14            liquidity,
15            amountTokenMin,
16            amountETHMin,
17            address(this),
18            deadline
19        );
20        TransferHelper.safeTransfer(token, to, IERC20(token).balanceOf(address(this)));
21        IWETH(WETH).withdraw(amountETH);
22        TransferHelper.safeTransferETH(to, amountETH);
23    }
24
25
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1
2
3    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
4        address token,
5        uint liquidity,
6        uint amountTokenMin,
7        uint amountETHMin,
8        address to,
9        uint deadline,
10        bool approveMax, uint8 v, bytes32 r, bytes32 s
11    ) external virtual override returns (uint amountETH) {
12        address pair = UniswapV2Library.pairFor(factory, token, WETH);
13        uint value = approveMax ? uint(-1) : liquidity;
14        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);
15        amountETH = removeLiquidityETHSupportingFeeOnTransferTokens(
16            token, liquidity, amountTokenMin, amountETHMin, to, deadline
17        );
18    }
19
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1    // **** SWAP ****
2    // requires the initial amount to have already been sent to the first pair
3    function _swap(uint[] memory amounts, address[] memory path, address _to) internal virtual {
4
 Αντιγραφή

1        for (uint i; i < path.length - 1; i++) {
2
 Αντιγραφή

1            (address input, address output) = (path[i], path[i + 1]);
2            (address token0,) = UniswapV2Library.sortTokens(input, output);
3            uint amountOut = amounts[i + 1];
4
 Αντιγραφή

1            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOut) : (amountOut, uint(0));
2
 Αντιγραφή

1            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
2
 Αντιγραφή

1
2            IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output)).swap(
3                amount0Out, amount1Out, to, new bytes(0)
4            );
5        }
6    }
7
 Αντιγραφή

1    function swapExactTokensForTokens(
2
 Αντιγραφή

1        uint amountIn,
2        uint amountOutMin,
3        address[] calldata path,
4
 Αντιγραφή

1        address to,
2        uint deadline
3    ) external virtual override ensure(deadline) returns (uint[] memory amounts) {
4
 Αντιγραφή

1        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
2        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
3
 Αντιγραφή

1        TransferHelper.safeTransferFrom(
2            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
3        );
4        _swap(amounts, path, to);
5    }
6
 Αντιγραφή

1    function swapTokensForExactTokens(
2        uint amountOut,
3        uint amountInMax,
4        address[] calldata path,
5        address to,
6        uint deadline
7    ) external virtual override ensure(deadline) returns (uint[] memory amounts) {
8        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
9        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
10        TransferHelper.safeTransferFrom(
11            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
12        );
13        _swap(amounts, path, to);
14    }
15
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1    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
2        external
3        virtual
4        override
5        payable
6        ensure(deadline)
7        returns (uint[] memory amounts)
8    {
9        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
10        amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
11        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
12        IWETH(WETH).deposit{value: amounts[0]}();
13        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
14        _swap(amounts, path, to);
15    }
16
17
18    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
19        external
20        virtual
21        override
22        ensure(deadline)
23        returns (uint[] memory amounts)
24    {
25        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
26        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
27        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
28        TransferHelper.safeTransferFrom(
29            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
30        );
31        _swap(amounts, path, address(this));
32        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
33        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
34    }
35
36
37
38    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
39        external
40        virtual
41        override
42        ensure(deadline)
43        returns (uint[] memory amounts)
44    {
45        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
46        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
47        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
48        TransferHelper.safeTransferFrom(
49            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
50        );
51        _swap(amounts, path, address(this));
52        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
53        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
54    }
55
56
57    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
58        external
59        virtual
60        override
61        payable
62        ensure(deadline)
63        returns (uint[] memory amounts)
64    {
65        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
66        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
67        require(amounts[0] <= msg.value, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
68        IWETH(WETH).deposit{value: amounts[0]}();
69        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
70        _swap(amounts, path, to);
71        // refund dust eth, if any
72        if (msg.value > amounts[0]) TransferHelper.safeTransferETH(msg.sender, msg.value - amounts[0]);
73    }
74
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1    // **** SWAP (supporting fee-on-transfer tokens) ****
2    // requires the initial amount to have already been sent to the first pair
3    function _swapSupportingFeeOnTransferTokens(address[] memory path, address _to) internal virtual {
4
 Αντιγραφή

1        for (uint i; i < path.length - 1; i++) {
2            (address input, address output) = (path[i], path[i + 1]);
3            (address token0,) = UniswapV2Library.sortTokens(input, output);
4            IUniswapV2Pair pair = IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output));
5            uint amountInput;
6            uint amountOutput;
7            { // scope to avoid stack too deep errors
8            (uint reserve0, uint reserve1,) = pair.getReserves();
9            (uint reserveInput, uint reserveOutput) = input == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
10            amountInput = IERC20(input).balanceOf(address(pair)).sub(reserveInput);
11            amountOutput = UniswapV2Library.getAmountOut(amountInput, reserveInput, reserveOutput);
12
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1            }
2            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOutput) : (amountOutput, uint(0));
3            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
4            pair.swap(amount0Out, amount1Out, to, new bytes(0));
5        }
6    }
7
8
9    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
10        uint amountIn,
11        uint amountOutMin,
12        address[] calldata path,
13        address to,
14        uint deadline
15    ) external virtual override ensure(deadline) {
16        TransferHelper.safeTransferFrom(
17            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
18        );
19        uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
20        _swapSupportingFeeOnTransferTokens(path, to);
21        require(
22            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
23            'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
24        );
25    }
26
27
28    function swapExactETHForTokensSupportingFeeOnTransferTokens(
29        uint amountOutMin,
30        address[] calldata path,
31        address to,
32        uint deadline
33    )
34        external
35        virtual
36        override
37        payable
38        ensure(deadline)
39    {
40        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
41        uint amountIn = msg.value;
42        IWETH(WETH).deposit{value: amountIn}();
43        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn));
44        uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
45        _swapSupportingFeeOnTransferTokens(path, to);
46        require(
47            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
48            'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
49        );
50    }
51
52
53    function swapExactTokensForETHSupportingFeeOnTransferTokens(
54        uint amountIn,
55        uint amountOutMin,
56        address[] calldata path,
57        address to,
58        uint deadline
59    )
60        external
61        virtual
62        override
63        ensure(deadline)
64    {
65        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
66        TransferHelper.safeTransferFrom(
67            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
68        );
69        _swapSupportingFeeOnTransferTokens(path, address(this));
70        uint amountOut = IERC20(WETH).balanceOf(address(this));
71        require(amountOut >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
72        IWETH(WETH).withdraw(amountOut);
73        TransferHelper.safeTransferETH(to, amountOut);
74    }
75
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1    // **** LIBRARY FUNCTIONS ****
2    function quote(uint amountA, uint reserveA, uint reserveB) public pure virtual override returns (uint amountB) {
3        return UniswapV2Library.quote(amountA, reserveA, reserveB);
4    }
5
6    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut)
7        public
8        pure
9        virtual
10        override
11        returns (uint amountOut)
12    {
13        return UniswapV2Library.getAmountOut(amountIn, reserveIn, reserveOut);
14    }
15
16    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut)
17        public
18        pure
19        virtual
20        override
21        returns (uint amountIn)
22    {
23        return UniswapV2Library.getAmountIn(amountOut, reserveIn, reserveOut);
24    }
25
26    function getAmountsOut(uint amountIn, address[] memory path)
27        public
28        view
29        virtual
30        override
31        returns (uint[] memory amounts)
32    {
33        return UniswapV2Library.getAmountsOut(factory, amountIn, path);
34    }
35
36    function getAmountsIn(uint amountOut, address[] memory path)
37        public
38        view
39        virtual
40        override
41        returns (uint[] memory amounts)
42    {
43        return UniswapV2Library.getAmountsIn(factory, amountOut, path);
44    }
45}
46
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1pragma solidity =0.5.16;
2
3// a library for performing various math operations
4
5library Math {
6    function min(uint x, uint y) internal pure returns (uint z) {
7        z = x < y ? x : y;
8    }
9
10    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
11    function sqrt(uint y) internal pure returns (uint z) {
12        if (y > 3) {
13            z = y;
14            uint x = y / 2 + 1;
15
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1            while (x < z) {
2                z = x;
3                x = (y / x + x) / 2;
4
 Αντιγραφή

1            }
2        } else if (y != 0) {
3            z = 1;
4
 Αντιγραφή

1        }
2    }
3}
4
 Αντιγραφή

1pragma solidity =0.5.16;
2
3// a library for handling binary fixed point numbers (https://en.wikipedia.org/wiki/Q_(number_format))
4
5// range: [0, 2**112 - 1]
6// resolution: 1 / 2**112
7
8library UQ112x112 {
9    uint224 constant Q112 = 2**112;
10
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1    // encode a uint112 as a UQ112x112
2    function encode(uint112 y) internal pure returns (uint224 z) {
3        z = uint224(y) * Q112; // never overflows
4    }
5
 Αντιγραφή

1    // divide a UQ112x112 by a uint112, returning a UQ112x112
2    function uqdiv(uint224 x, uint112 y) internal pure returns (uint224 z) {
3        z = x / uint224(y);
4    }
5}
6
 Αντιγραφή

1pragma solidity >=0.5.0;
2
3import '@uniswap/v2-core/contracts/interfaces/IUniswapV2Pair.sol';
4
5import "./SafeMath.sol";
6
7library UniswapV2Library {
8    using SafeMath for uint;
9
10    // returns sorted token addresses, used to handle return values from pairs sorted in this order
11    function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) {
12        require(tokenA != tokenB, 'UniswapV2Library: IDENTICAL_ADDRESSES');
13        (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
14        require(token0 != address(0), 'UniswapV2Library: ZERO_ADDRESS');
15    }
16
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1    // calculates the CREATE2 address for a pair without making any external calls
2    function pairFor(address factory, address tokenA, address tokenB) internal pure returns (address pair) {
3        (address token0, address token1) = sortTokens(tokenA, tokenB);
4        pair = address(uint(keccak256(abi.encodePacked(
5                hex'ff',
6                factory,
7                keccak256(abi.encodePacked(token0, token1)),
8                hex'96e8ac4277198ff8b6f785478aa9a39f403cb768dd02cbee326c3e7da348845f' // init code hash
9            ))));
10    }
11
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1    // fetches and sorts the reserves for a pair
2    function getReserves(address factory, address tokenA, address tokenB) internal view returns (uint reserveA, uint reserveB) {
3        (address token0,) = sortTokens(tokenA, tokenB);
4        (uint reserve0, uint reserve1,) = IUniswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves();
5        (reserveA, reserveB) = tokenA == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
6    }
7
 Αντιγραφή

1    // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset
2    function quote(uint amountA, uint reserveA, uint reserveB) internal pure returns (uint amountB) {
3        require(amountA > 0, 'UniswapV2Library: INSUFFICIENT_AMOUNT');
4        require(reserveA > 0 && reserveB > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
5        amountB = amountA.mul(reserveB) / reserveA;
6    }
7
 Αντιγραφή

1    // given an input amount of an asset and pair reserves, returns the maximum output amount of the other asset
2    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) internal pure returns (uint amountOut) {
3
 Αντιγραφή

1
2        require(amountIn > 0, 'UniswapV2Library: INSUFFICIENT_INPUT_AMOUNT');
3        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
4        uint amountInWithFee = amountIn.mul(997);
5        uint numerator = amountInWithFee.mul(reserveOut);
6        uint denominator = reserveIn.mul(1000).add(amountInWithFee);
7        amountOut = numerator / denominator;
8    }
9
 Αντιγραφή

1    // given an output amount of an asset and pair reserves, returns a required input amount of the other asset
2    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) internal pure returns (uint amountIn) {
3        require(amountOut > 0, 'UniswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT');
4        require(reserveIn > 0 && reserveOut > 0, 'UniswapV2Library: INSUFFICIENT_LIQUIDITY');
5        uint numerator = reserveIn.mul(amountOut).mul(1000);
6        uint denominator = reserveOut.sub(amountOut).mul(997);
7        amountIn = (numerator / denominator).add(1);
8    }
9
 Αντιγραφή

1
2    // performs chained getAmountOut calculations on any number of pairs
3    function getAmountsOut(address factory, uint amountIn, address[] memory path) internal view returns (uint[] memory amounts) {
4        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
5        amounts = new uint[](path.length);
6        amounts[0] = amountIn;
7        for (uint i; i < path.length - 1; i++) {
8            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i], path[i + 1]);
9            amounts[i + 1] = getAmountOut(amounts[i], reserveIn, reserveOut);
10        }
11    }
12
13    // performs chained getAmountIn calculations on any number of pairs
14    function getAmountsIn(address factory, uint amountOut, address[] memory path) internal view returns (uint[] memory amounts) {
15        require(path.length >= 2, 'UniswapV2Library: INVALID_PATH');
16        amounts = new uint[](path.length);
17        amounts[amounts.length - 1] = amountOut;
18        for (uint i = path.length - 1; i > 0; i--) {
19            (uint reserveIn, uint reserveOut) = getReserves(factory, path[i - 1], path[i]);
20            amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut);
21        }
22    }
23}
24
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1// SPDX-License-Identifier: GPL-3.0-or-later
2
3pragma solidity >=0.6.0;
4
5// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
6library TransferHelper {
7    function safeApprove(
8        address token,
9        address to,
10        uint256 value
11    ) internal {
12        // bytes4(keccak256(bytes('approve(address,uint256)')));
13        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
14
15
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1        require(
2            success && (data.length == 0 || abi.decode(data, (bool))),
3            'TransferHelper::safeApprove: approve failed'
4        );
5    }
6
 Αντιγραφή

1
2
3    function safeTransfer(
4        address token,
5        address to,
6        uint256 value
7    ) internal {
8        // bytes4(keccak256(bytes('transfer(address,uint256)')));
9        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
10        require(
11            success && (data.length == 0 || abi.decode(data, (bool))),
12            'TransferHelper::safeTransfer: transfer failed'
13        );
14    }
15
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1
2    function safeTransferFrom(
3        address token,
4        address from,
5        address to,
6        uint256 value
7    ) internal {
8        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
9        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
10        require(
11            success && (data.length == 0 || abi.decode(data, (bool))),
12            'TransferHelper::transferFrom: transferFrom failed'
13        );
14    }
15
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1
2    function safeTransferETH(address to, uint256 value) internal {
3        (bool success, ) = to.call{value: value}(new bytes(0));
4        require(success, 'TransferHelper::safeTransferETH: ETH transfer failed');
5    }
6}
7
 Αντιγραφή