From a technical perspective, blockchain enables every node of digital asset value flow to be transparent, traceable, and tamper proof, making all transactions in the Web 3.0 era more authentic and trustworthy.
At the same time, data ownership can be determined through blockchain technology, achieving data assetization, which will also make blockchain the infrastructure of the Web 3.0 era.
Smart contract dapp development technology is a blockchain based development technology that can help developers quickly and efficiently develop powerful and reliable dapps (decentralized applications).
Dapp custom development technology is used to provide better customized development services for Dapp developers, helping them build powerful and reliable Dapp more quickly.
function swap(uint amount0Out,uint amount1Out,address to,bytes calldata data)external lock{
require(amount0Out>0||amount1Out>0,'UniswapV2:INSUFFICIENT_OUTPUT_AMOUNT');
(uint112 _reserve0,uint112 _reserve1,)=getReserves();//gas savings
require(amount0Out<_reserve0&&amount1Out<_reserve1,'UniswapV2: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,'UniswapV2: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)IUniswapV2Callee(to).uniswapV2Call(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,'UniswapV2: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),'UniswapV2:K');
}
_update(balance0,balance1,_reserve0,_reserve1);
emit Swap(msg.sender,amount0In,amount1In,amount0Out,amount1Out,to);
}
