pragma solidity >=0.5.0; import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol"; import "@uniswap/v2-core/contracts/interfaces/IUniswapV2Pair.sol"; import "@uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol"; library UniswapV2Library { using SafeMath for uint256; // returns sorted token addresses, used to handle return values from pairs sorted in this order function sortTokens(address tokenA, address tokenB) internal pure returns (address token0, address token1) { require(tokenA != tokenB, "UniswapV2Library: IDENTICAL_ADDRESSES"); (token0, token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA); require(token0 != address(0), "UniswapV2Library: ZERO_ADDRESS"); } // calculates the CREATE2 address for a pair without making any external calls function pairFor( address factory, address tokenA, address tokenB ) internal view returns (address pair) { return IUniswapV2Factory(factory).getPair(tokenA, tokenB); // For easy testing // (address token0, address token1) = sortTokens(tokenA, tokenB); // pair = address( // uint256( // keccak256( // abi.encodePacked( // hex'ff', // factory, // keccak256(abi.encodePacked(token0, token1)), // hex'fc4928e335b531bb85a6d9454f46863f9d6101351e3e8b84620b1806d4a3fcb3' // init code hash // ) // ) // ) // ); } // fetches and sorts the reserves for a pair function getReserves( address factory, address tokenA, address tokenB ) internal view returns (uint256 reserveA, uint256 reserveB) { (address token0, ) = sortTokens(tokenA, tokenB); (uint256 reserve0, uint256 reserve1, ) = IUniswapV2Pair(pairFor(factory, tokenA, tokenB)).getReserves(); (reserveA, reserveB) = tokenA == token0 ? (reserve0, reserve1) : (reserve1, reserve0); } // given some amount of an asset and pair reserves, returns an equivalent amount of the other asset function quote( uint256 amountA, uint256 reserveA, uint256 reserveB ) internal pure returns (uint256 amountB) { require(amountA > 0, "UniswapV2Library: INSUFFICIENT_AMOUNT"); require(reserveA > 0 && reserveB > 0, "UniswapV2Library: INSUFFICIENT_LIQUIDITY"); amountB = amountA.mul(reserveB) / reserveA; } // given an input amount of an asset and pair reserves, returns the maximum output amount of the other asset function getAmountOut( uint256 amountIn, uint256 reserveIn, uint256 reserveOut ) internal pure returns (uint256 amountOut) { require(amountIn > 0, "UniswapV2Library: INSUFFICIENT_INPUT_AMOUNT"); require(reserveIn > 0 && reserveOut > 0, "UniswapV2Library: INSUFFICIENT_LIQUIDITY"); uint256 amountInWithFee = amountIn.mul(997); uint256 numerator = amountInWithFee.mul(reserveOut); uint256 denominator = reserveIn.mul(1000).add(amountInWithFee); amountOut = numerator / denominator; } // given an output amount of an asset and pair reserves, returns a required input amount of the other asset function getAmountIn( uint256 amountOut, uint256 reserveIn, uint256 reserveOut ) internal pure returns (uint256 amountIn) { require(amountOut > 0, "UniswapV2Library: INSUFFICIENT_OUTPUT_AMOUNT"); require(reserveIn > 0 && reserveOut > 0, "UniswapV2Library: INSUFFICIENT_LIQUIDITY"); uint256 numerator = reserveIn.mul(amountOut).mul(1000); uint256 denominator = reserveOut.sub(amountOut).mul(997); amountIn = (numerator / denominator).add(1); } // performs chained getAmountOut calculations on any number of pairs function getAmountsOut( address factory, uint256 amountIn, address[] memory path ) internal view returns (uint256[] memory amounts) { require(path.length >= 2, "UniswapV2Library: INVALID_PATH"); amounts = new uint256[](path.length); amounts[0] = amountIn; for (uint256 i; i < path.length - 1; i++) { (uint256 reserveIn, uint256 reserveOut) = getReserves(factory, path[i], path[i + 1]); amounts[i + 1] = getAmountOut(amounts[i], reserveIn, reserveOut); } } // performs chained getAmountIn calculations on any number of pairs function getAmountsIn( address factory, uint256 amountOut, address[] memory path ) internal view returns (uint256[] memory amounts) { require(path.length >= 2, "UniswapV2Library: INVALID_PATH"); amounts = new uint256[](path.length); amounts[amounts.length - 1] = amountOut; for (uint256 i = path.length - 1; i > 0; i--) { (uint256 reserveIn, uint256 reserveOut) = getReserves(factory, path[i - 1], path[i]); amounts[i - 1] = getAmountIn(amounts[i], reserveIn, reserveOut); } } }
0.4.18