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qct/packCalldata

Forked from 0xmebius/packCalldata
Created February 19, 2022 12:31
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  1. @0xmebius 0xmebius created this gist Dec 11, 2021.
    76 changes: 76 additions & 0 deletions packCalldata
    View file
    Original file line number Diff line number Diff line change
    @@ -0,0 +1,76 @@
    object "Contract" {
    code {
    datacopy(0, dataoffset("runtime"), datasize("runtime"))
    return(0, datasize("runtime"))
    }
    object "runtime" {
    code {
    if iszero(calledByOwner()) { revert(0, 0) }
    switch selector()
    case 0x00 {
    let tokenIn := shr(0x60, calldataload(0x01))
    let tokenOut := shr(0x60, calldataload(0x15))
    let amountIn := decodeAsUint112(0x29)

    let pair := getPair(tokenIn, tokenOut)
    let reserveOut, reserveIn := getReserves(pair)
    let amountOut := getAmountOut(amountIn, reserveIn, reserveOut)
    transfer(tokenIn, pair, amountIn)

    mstore(0, shl(0xe0, 0x022c0d9f)) mstore(add(0, 0x04), amountOut)
    mstore(add(0, 0x44), address()) mstore(add(0, 0x64), 0x80)
    if iszero(call(gas(), pair, 0, 0, 0x84, 0, 0)) { revert(0, 0) }
    }
    case 0x01 {
    let tokenIn := shr(0x60, calldataload(0x01))
    let tokenOut := shr(0x60, calldataload(0x15))
    let amountIn := decodeAsUint112(0x29)

    let pair := getPair(tokenIn, tokenOut)
    let reserveIn, reserveOut := getReserves(pair)
    let amountOut := getAmountOut(amountIn, reserveIn, reserveOut)
    transfer(tokenIn, pair, amountIn)

    mstore(0, shl(0xe0, 0x022c0d9f)) mstore(add(0, 0x24), amountOut)
    mstore(add(0, 0x44), address()) mstore(add(0, 0x64), 0x80)
    if iszero(call(gas(), pair, 0, 0, 0x84, 0, 0)) { revert(0, 0) }
    }
    case 0x02 { revert(0, 0) } // Withdraw
    default {
    revert(0, 0)
    }
    function calledByOwner() -> cbo {
    cbo := eq(0x0000000000000000000000000000000000000000, caller())
    }
    function selector() -> s { // 1 byte
    s := shr(0xf8, calldataload(0))
    }
    function decodeAsUint112(_pos) -> v { // 2^112-1
    v := shr(sub(0x100, mul(8, sub(calldatasize(), _pos))), calldataload(_pos))
    }
    // ↓ This sucks and should be deprecated
    function getPair(token0, token1) -> p {
    mstore(0, shl(0xe0, 0xe6a43905)) mstore(add(0, 0x04), token0) mstore(add(0, 0x24), token1)
    if iszero(staticcall(gas(), 0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f, 0, 0x44, 0x44, 0x20)) { revert(0, 0) }
    p := mload(0x44)
    }
    function getAmountOut(amountIn, reserveIn, reserveOut) -> v {
    let aiwf := mul(amountIn, 9970)
    v := div(mul(reserveOut, aiwf), add(mul(reserveIn,10000), aiwf))
    }
    function getReserves(pair) -> r0, r1 {
    mstore(0, shl(0xe0, 0x0902f1ac))
    if iszero(staticcall(gas(), pair, 0, 0x04, 0x04, 0x40)) { revert(0, 0) }
    r0 := mload(0x04)
    r1 := mload(0x24)
    }
    function transfer(token, dst, wad) {
    mstore(0, shl(0xe0, 0xa9059cbb)) mstore(add(0, 0x04), dst) mstore(add(0, 0x24), wad)
    if iszero(call(gas(), token, 0, 0, 0x44, 0, 0)) { revert(0, 0) }
    }
    /* ---------- Staging functions ---------- */
    function getPairNew(token0, token1) -> p { revert(0, 0) }
    function sortTokens(tokenA, tokenB) -> token0, token1 { revert(0, 0) }
    }
    }
    }