| // SPDX-License-Identifier: MIT | |
| // @author Jesper Kristensen (@cryptojesperk) | |
| pragma solidity 0.8.7; | |
| contract StorageLayout { | |
| uint x = 2; | |
| mapping(uint => uint) m; | |
| function addToM(uint key, uint value) public { | |
| m[key] = value; | |
| } | |
| // HELPER TO READ FROM STORAGE SLOTS | |
| function readStorageSlot(uint256 i) public view returns (bytes32 content) { | |
| assembly { | |
| content := sload(i) | |
| } | |
| } | |
| // HELPER TO GET THE SLOT INDEX OF A MAPPING'S VALUE UNDER IT'S GIVEN KEY | |
| function getLocationOfMapping(uint mappingSlot, uint key) public pure returns (uint slot) { | |
| // mappingSlot: the slot that the mapping itself sits in -> here: it's slot 1 | |
| // slot: the slot that the value will be sitting in, e.g.: m[key] = value --> value will sit in "slot." | |
| return uint256(keccak256(abi.encode(key, mappingSlot))); | |
| } | |
| } |