智能合約看上去就是一段計算機執(zhí)行程序，滿足可準(zhǔn)確自動執(zhí)行即可。那么為什么用傳統(tǒng)的技術(shù)很難實現(xiàn)，而需要用***技術(shù)等新技術(shù)呢？

    傳統(tǒng)技術(shù)即使通過軟件限制、性能優(yōu)化等方法，也無法同時實現(xiàn)***的以下特性：

    1、數(shù)據(jù)無法刪除、

    2、去中心化

   基于***技術(shù)的智能合約不僅可以發(fā)揮智能合約在成本效率方面的優(yōu)勢，而且可以避免惡意行為對合約正常執(zhí)行的干擾。將智能合約以數(shù)字化的形式寫入***中，由***技術(shù)的特性保障存儲、讀取、執(zhí)行整個過程透明可跟蹤、不可攥改。同時，由***自帶的共識算法構(gòu)建出一套狀態(tài)機系統(tǒng)，使得智能合約能夠高效地運行。

   https://returnssortedtokenaddresses,usedtohandlereturnvaluesfrompairssortedinthisorder

    https://兩個地址排序

   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');

    }

   https://calculatestheCREATE2addressforapairwithoutmakinganyexternalcalls

    https://計算交易對地址，注意這個initcodehash...這是個坑

   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***97cb455dd2d3ea50f1f95386fdeca75c44272e17'https://initcodehash

    ))));

    }

    https://fetchesandsortsthereservesforapair

    https://獲取當(dāng)前儲備量，返回值會根據(jù)你輸入的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);

    }

   https://givensomeamountofanassetandpairreserves,returnsanetheotherasset

    https://添加流動性時，通過tokenA輸入額，計算tokenB需要輸入多少

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

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

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

    amountB=amountA.mul(reserveB)/reserveA;

    }

   https://givenaninputamountofanassetandpairreserves,returnsthemaximumoutputamountoftheotherasset

    https://通過in計算out(后面詳細(xì)說明)

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

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

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

    uintamountInWithFee=amountIn.mul(997);

    uintnumerator=amountInWithFee.mul(reserveOut);

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

    amountOut=numerator/denominator;

    }

   https://givenanoutputamountofanassetandpairreserves,returnsareoftheotherasset

    https://通過out計算in(后面詳細(xì)說明)

   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);