I wanna compute sha256 in Solidity Assembly for hash of getting bytes slice.
Sha256 is one of a few precompiled smart contracts:
function subSha256(bytes memory data, uint256 offset, uint256 length) public view returns(bytes32) {
bytes32[1] memory result;
assembly {
pop(staticcall(gas, 0x02, add(add(data, 32), offset), length, result, 32))
}
return result[0];
}
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I'm pretty sure that in solc 0.5.x onward, you can simply use
staticcallat the Solidity level, and get(bool success, bytes memory result)returned to you. – goodvibration May 26 '20 at 16:54 -
@goodvibration core feature of this code is getting hash for a slice of an array without copying it into separate bytes array. – k06a May 26 '20 at 17:48
