// SPDX-License-Identifier: MIT // This file was procedurally generated from scripts/generate/templates/SlotDerivation.js. pragma solidity ^0.8.20; /** * @dev Library for computing storage (and transient storage) locations from namespaces and deriving slots * corresponding to standard patterns. The derivation method for array and mapping matches the storage layout used by * the solidity language / compiler. * * See https://docs.soliditylang.org/en/v0.8.20/internals/layout_in_storage.html#mappings-and-dynamic-arrays[Solidity docs for mappings and dynamic arrays.]. * * Example usage: * ```solidity * contract Example { * // Add the library methods * using StorageSlot for bytes32; * using SlotDerivation for bytes32; * * // Declare a namespace * string private constant _NAMESPACE = "" // eg. OpenZeppelin.Slot * * function setValueInNamespace(uint256 key, address newValue) internal { * _NAMESPACE.erc7201Slot().deriveMapping(key).getAddressSlot().value = newValue; * } * * function getValueInNamespace(uint256 key) internal view returns (address) { * return _NAMESPACE.erc7201Slot().deriveMapping(key).getAddressSlot().value; * } * } * ``` * * TIP: Consider using this library along with {StorageSlot}. * * NOTE: This library provides a way to manipulate storage locations in a non-standard way. Tooling for checking * upgrade safety will ignore the slots accessed through this library. */ library SlotDerivation { /** * @dev Derive an ERC-7201 slot from a string (namespace). */ function erc7201Slot(string memory namespace) internal pure returns (bytes32 slot) { /// @solidity memory-safe-assembly assembly { mstore(0x00, sub(keccak256(add(namespace, 0x20), mload(namespace)), 1)) slot := and(keccak256(0x00, 0x20), not(0xff)) } } /** * @dev Add an offset to a slot to get the n-th element of a structure or an array. */ function offset(bytes32 slot, uint256 pos) internal pure returns (bytes32 result) { unchecked { return bytes32(uint256(slot) + pos); } } /** * @dev Derive the location of the first element in an array from the slot where the length is stored. */ function deriveArray(bytes32 slot) internal pure returns (bytes32 result) { /// @solidity memory-safe-assembly assembly { mstore(0x00, slot) result := keccak256(0x00, 0x20) } } /** * @dev Derive the location of a mapping element from the key. */ function deriveMapping(bytes32 slot, address key) internal pure returns (bytes32 result) { /// @solidity memory-safe-assembly assembly { mstore(0x00, key) mstore(0x20, slot) result := keccak256(0x00, 0x40) } } /** * @dev Derive the location of a mapping element from the key. */ function deriveMapping(bytes32 slot, bool key) internal pure returns (bytes32 result) { /// @solidity memory-safe-assembly assembly { mstore(0x00, key) mstore(0x20, slot) result := keccak256(0x00, 0x40) } } /** * @dev Derive the location of a mapping element from the key. */ function deriveMapping(bytes32 slot, bytes32 key) internal pure returns (bytes32 result) { /// @solidity memory-safe-assembly assembly { mstore(0x00, key) mstore(0x20, slot) result := keccak256(0x00, 0x40) } } /** * @dev Derive the location of a mapping element from the key. */ function deriveMapping(bytes32 slot, uint256 key) internal pure returns (bytes32 result) { /// @solidity memory-safe-assembly assembly { mstore(0x00, key) mstore(0x20, slot) result := keccak256(0x00, 0x40) } } /** * @dev Derive the location of a mapping element from the key. */ function deriveMapping(bytes32 slot, int256 key) internal pure returns (bytes32 result) { /// @solidity memory-safe-assembly assembly { mstore(0x00, key) mstore(0x20, slot) result := keccak256(0x00, 0x40) } } /** * @dev Derive the location of a mapping element from the key. */ function deriveMapping(bytes32 slot, string memory key) internal pure returns (bytes32 result) { /// @solidity memory-safe-assembly assembly { let length := mload(key) let begin := add(key, 0x20) let end := add(begin, length) let cache := mload(end) mstore(end, slot) result := keccak256(begin, add(length, 0x20)) mstore(end, cache) } } /** * @dev Derive the location of a mapping element from the key. */ function deriveMapping(bytes32 slot, bytes memory key) internal pure returns (bytes32 result) { /// @solidity memory-safe-assembly assembly { let length := mload(key) let begin := add(key, 0x20) let end := add(begin, length) let cache := mload(end) mstore(end, slot) result := keccak256(begin, add(length, 0x20)) mstore(end, cache) } } }