永续合约开发（稳定版）丨永续合约系统开发（方案及案例）丨永续合约现成源码部署

产品详情

    智能合约看上去就是一段计算机执行程序，满足可准确自动执行即可。那么为什么用传统的技术很难实现，而需要用***技术等新技术呢？

    传统技术即使通过软件限制、性能优化等方法，也无法同时实现***的以下特性：

    1、数据无法删除、

    2、去中心化

    基于***技术的智能合约不仅可以发挥智能合约在成本效率方面的优势，而且可以避免恶意行为对合约正常执行的干扰。将智能合约以数字化的形式写入***中，由***技术的特性保障存储、读取、执行整个过程透明可跟踪、不可攥改。同时，由***自带的共识算法构建出一套状态机系统，使得智能合约能够高效地运行。

    //returnssortedtokenaddresses,usedtohandlereturnvaluesfrompairssortedinthisorder

    //两个地址排序

    functionsortTokens(addresstokenA,addresstokenB)internalpurereturns(addresstoken0,addresstoken1){

    require(tokenA!=tokenB,'UniswapV2Library:IDENTICAL_ADDRESSES');

    (token0,token1)=tokenA<tokenB?(tokenA,tokenB):(tokenB,tokenA);

    require(token0!=address(0),'UniswapV2Library:ZERO_ADDRESS');

    }

    //calculatestheCREATE2addressforapairwithoutmakinganyexternalcalls

    //计算交易对地址，注意这个initcodehash...这是个坑

    functionpairFor(addressfactory,addresstokenA,addresstokenB)internalpurereturns(addresspair){

    (addresstoken0,addresstoken1)=sortTokens(tokenA,tokenB);

    pair=address(uint(keccak256(abi.encodePacked(

    hex'ff',

    factory,

    keccak256(abi.encodePacked(token0,token1)),

    hex'de683***97cb455dd2d3ea50f1f95386fdeca75180cc01bb6b12207c44272e17'//initcodehash

    ))));

    }

    //fetchesandsortsthereservesforapair

    //获取当前储备量，返回值会根据你输入的token排序

    functiongetReserves(addressfactory,addresstokenA,addresstokenB)internalviewreturns(uintreserveA,uintreserveB){

    (addresstoken0,)=sortTokens(tokenA,tokenB);

    (uintreserve0,uintreserve1,)=IUniswapV2Pair(pairFor(factory,tokenA,tokenB)).getReserves();

    (reserveA,reserveB)=tokenA==token0?(reserve0,reserve1):(reserve1,reserve0);

    }

    //givensomeamountofanassetandpairreserves,returnsanequivalentamountoftheotherasset

    //添加流动性时，通过tokenA输入额，计算tokenB需要输入多少

    functionquote(uintamountA,uintreserveA,uintreserveB)internalpurereturns(uintamountB){

    require(amountA>0,'UniswapV2Library:INSUFFICIENT_AMOUNT');

    require(reserveA>0&&reserveB>0,'UniswapV2Library:INSUFFICIENT_LIQUIDITY');

    amountB=amountA.mul(reserveB)/reserveA;

    }

    //givenaninputamountofanassetandpairreserves,returnsthemaximumoutputamountoftheotherasset

    //通过in计算out(后面详细说明)

    functiongetAmountOut(uintamountIn,uintreserveIn,uintreserveOut)internalpurereturns(uintamountOut){

    require(amountIn>0,'UniswapV2Library:INSUFFICIENT_INPUT_AMOUNT');

    require(reserveIn>0&&reserveOut>0,'UniswapV2Library:INSUFFICIENT_LIQUIDITY');

    uintamountInWithFee=amountIn.mul(997);

    uintnumerator=amountInWithFee.mul(reserveOut);

    uintdenominator=reserveIn.mul(1000).add(amountInWithFee);

    amountOut=numerator/denominator;

    }

    //givenanoutputamountofanassetandpairreserves,returnsarequiredinputamountoftheotherasset

    //通过out计算in(后面详细说明)

    functiongetAmountIn(uintamountOut,uintreserveIn,uintreserveOut)internalpurereturns(uintamountIn){

    require(amountOut>0,'UniswapV2Library:INSUFFICIENT_OUTPUT_AMOUNT');

    uintnumerator=reserveIn.mul(amountOut).mul(1000);

    uintdenominator=reserveOut.sub(amountOut).mul(997);

    amountIn=(numerator/denominator).add(1);