Contract Source Code:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.28;

import "solady/auth/Ownable.sol";
import "solady/utils/SSTORE2.sol";

/// @title ContentStore
/// @notice Stores chunked content (images, game data) in contract bytecode
/// @dev Uses SSTORE2 for gas-efficient storage (~200 gas/byte vs 20000 gas/slot)
contract ContentStore is Ownable {

    /// @dev Location of stored data
    struct DataLoc {
        address pointer;
        uint48 start;
        uint48 end;
    }

    /// @dev Content entry with optional chunking
    struct Content {
        uint24 chunkCount;
        bytes32 contentType;  // e.g., keccak256("image/webp"), keccak256("application/javascript")
        mapping(uint256 => address) chunks;
    }

    mapping(uint256 => Content) internal contents;
    mapping(uint256 => DataLoc) internal locations;  // For single-pointer small content

    uint256 public nextId = 1;

    event ContentStored(uint256 indexed id, bytes32 contentType);
    event ChunkStored(uint256 indexed id, uint256 index);

    error ContentNotFound();
    error ChunkOutOfBounds();
    error EmptyData();

    constructor(address owner_) {
        _initializeOwner(owner_);
    }

    /// @notice Store small content in single transaction
    /// @param contentType Type identifier
    /// @param data Content bytes
    /// @return id Content ID
    function store(bytes32 contentType, bytes calldata data) external onlyOwner returns (uint256 id) {
        if (data.length == 0) revert EmptyData();

        id = nextId++;
        address pointer = SSTORE2.write(data);
        locations[id] = DataLoc(pointer, 0, uint48(data.length));
        contents[id].contentType = contentType;

        emit ContentStored(id, contentType);
    }

    /// @notice Store content at specific ID
    /// @param id Content ID
    /// @param contentType Type identifier
    /// @param data Content bytes
    function storeAt(uint256 id, bytes32 contentType, bytes calldata data) external onlyOwner {
        if (data.length == 0) revert EmptyData();

        if (id >= nextId) nextId = id + 1;

        address pointer = SSTORE2.write(data);
        locations[id] = DataLoc(pointer, 0, uint48(data.length));
        contents[id].contentType = contentType;

        emit ContentStored(id, contentType);
    }

    /// @notice Initialize chunked content
    /// @param id Content ID
    /// @param contentType Type identifier
    function initChunked(uint256 id, bytes32 contentType) external onlyOwner {
        if (id >= nextId) nextId = id + 1;
        contents[id].contentType = contentType;
        emit ContentStored(id, contentType);
    }

    /// @notice Add chunk to content
    /// @param id Content ID
    /// @param chunk Chunk data
    function addChunk(uint256 id, bytes calldata chunk) external onlyOwner {
        if (contents[id].contentType == bytes32(0)) revert ContentNotFound();
        if (chunk.length == 0) revert EmptyData();

        uint256 index = contents[id].chunkCount;
        contents[id].chunks[index] = SSTORE2.write(chunk);
        contents[id].chunkCount++;

        emit ChunkStored(id, index);
    }

    /// @notice Add multiple chunks
    /// @param id Content ID
    /// @param chunks Array of chunk data
    function addChunks(uint256 id, bytes[] calldata chunks) external onlyOwner {
        if (contents[id].contentType == bytes32(0)) revert ContentNotFound();

        uint256 startIndex = contents[id].chunkCount;
        for (uint256 i; i < chunks.length; ++i) {
            if (chunks[i].length == 0) revert EmptyData();
            contents[id].chunks[startIndex + i] = SSTORE2.write(chunks[i]);
            emit ChunkStored(id, startIndex + i);
        }
        contents[id].chunkCount += uint24(chunks.length);
    }

    /// @notice Batch store multiple small contents
    /// @param contentType Type identifier for all
    /// @param dataArray Array of content bytes
    /// @return startId First content ID
    function storeBatch(bytes32 contentType, bytes[] calldata dataArray) external onlyOwner returns (uint256 startId) {
        startId = nextId;

        for (uint256 i; i < dataArray.length; ++i) {
            if (dataArray[i].length == 0) revert EmptyData();
            uint256 id = nextId++;
            address pointer = SSTORE2.write(dataArray[i]);
            locations[id] = DataLoc(pointer, 0, uint48(dataArray[i].length));
            contents[id].contentType = contentType;
            emit ContentStored(id, contentType);
        }
    }

    /// @notice Get content bytes
    /// @param id Content ID
    /// @return Content as bytes
    function get(uint256 id) external view returns (bytes memory) {
        Content storage content = contents[id];
        if (content.contentType == bytes32(0)) revert ContentNotFound();

        // Single storage
        DataLoc memory loc = locations[id];
        if (loc.pointer != address(0)) {
            return SSTORE2.read(loc.pointer, loc.start, loc.end);
        }

        // Chunked storage
        bytes memory result;
        for (uint256 i; i < content.chunkCount; ++i) {
            result = bytes.concat(result, SSTORE2.read(content.chunks[i]));
        }
        return result;
    }

    /// @notice Get content as string
    /// @param id Content ID
    /// @return Content as string
    function getString(uint256 id) external view returns (string memory) {
        return string(this.get(id));
    }

    /// @notice Get single chunk
    /// @param id Content ID
    /// @param index Chunk index
    /// @return Chunk bytes
    function getChunk(uint256 id, uint256 index) external view returns (bytes memory) {
        Content storage content = contents[id];
        if (content.contentType == bytes32(0)) revert ContentNotFound();
        if (index >= content.chunkCount) revert ChunkOutOfBounds();
        return SSTORE2.read(content.chunks[index]);
    }

    /// @notice Get content info
    /// @param id Content ID
    /// @return contentType Content type
    /// @return chunkCount Number of chunks (0 if single storage)
    function getInfo(uint256 id) external view returns (bytes32 contentType, uint24 chunkCount) {
        Content storage content = contents[id];
        if (content.contentType == bytes32(0)) revert ContentNotFound();
        return (content.contentType, content.chunkCount);
    }

    /// @notice Check if content exists
    /// @param id Content ID
    /// @return True if exists
    function exists(uint256 id) external view returns (bool) {
        return contents[id].contentType != bytes32(0);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

/// @notice Read and write to persistent storage at a fraction of the cost.
/// @author Solady (https://github.com/vectorized/solady/blob/main/src/utils/SSTORE2.sol)
/// @author Saw-mon-and-Natalie (https://github.com/Saw-mon-and-Natalie)
/// @author Modified from Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/SSTORE2.sol)
/// @author Modified from 0xSequence (https://github.com/0xSequence/sstore2/blob/master/contracts/SSTORE2.sol)
/// @author Modified from SSTORE3 (https://github.com/Philogy/sstore3)
library SSTORE2 {
    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                         CONSTANTS                          */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev The proxy initialization code.
    uint256 private constant _CREATE3_PROXY_INITCODE = 0x67363d3d37363d34f03d5260086018f3;

    /// @dev Hash of the `_CREATE3_PROXY_INITCODE`.
    /// Equivalent to `keccak256(abi.encodePacked(hex"67363d3d37363d34f03d5260086018f3"))`.
    bytes32 internal constant CREATE3_PROXY_INITCODE_HASH =
        0x21c35dbe1b344a2488cf3321d6ce542f8e9f305544ff09e4993a62319a497c1f;

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                        CUSTOM ERRORS                       */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Unable to deploy the storage contract.
    error DeploymentFailed();

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                         WRITE LOGIC                        */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Writes `data` into the bytecode of a storage contract and returns its address.
    function write(bytes memory data) internal returns (address pointer) {
        /// @solidity memory-safe-assembly
        assembly {
            let n := mload(data) // Let `l` be `n + 1`. +1 as we prefix a STOP opcode.
            /**
             * ---------------------------------------------------+
             * Opcode | Mnemonic       | Stack     | Memory       |
             * ---------------------------------------------------|
             * 61 l   | PUSH2 l        | l         |              |
             * 80     | DUP1           | l l       |              |
             * 60 0xa | PUSH1 0xa      | 0xa l l   |              |
             * 3D     | RETURNDATASIZE | 0 0xa l l |              |
             * 39     | CODECOPY       | l         | [0..l): code |
             * 3D     | RETURNDATASIZE | 0 l       | [0..l): code |
             * F3     | RETURN         |           | [0..l): code |
             * 00     | STOP           |           |              |
             * ---------------------------------------------------+
             * @dev Prefix the bytecode with a STOP opcode to ensure it cannot be called.
             * Also PUSH2 is used since max contract size cap is 24,576 bytes which is less than 2 ** 16.
             */
            // Do a out-of-gas revert if `n + 1` is more than 2 bytes.
            mstore(add(data, gt(n, 0xfffe)), add(0xfe61000180600a3d393df300, shl(0x40, n)))
            // Deploy a new contract with the generated creation code.
            pointer := create(0, add(data, 0x15), add(n, 0xb))
            if iszero(pointer) {
                mstore(0x00, 0x30116425) // `DeploymentFailed()`.
                revert(0x1c, 0x04)
            }
            mstore(data, n) // Restore the length of `data`.
        }
    }

    /// @dev Writes `data` into the bytecode of a storage contract with `salt`
    /// and returns its normal CREATE2 deterministic address.
    function writeCounterfactual(bytes memory data, bytes32 salt)
        internal
        returns (address pointer)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let n := mload(data)
            // Do a out-of-gas revert if `n + 1` is more than 2 bytes.
            mstore(add(data, gt(n, 0xfffe)), add(0xfe61000180600a3d393df300, shl(0x40, n)))
            // Deploy a new contract with the generated creation code.
            pointer := create2(0, add(data, 0x15), add(n, 0xb), salt)
            if iszero(pointer) {
                mstore(0x00, 0x30116425) // `DeploymentFailed()`.
                revert(0x1c, 0x04)
            }
            mstore(data, n) // Restore the length of `data`.
        }
    }

    /// @dev Writes `data` into the bytecode of a storage contract and returns its address.
    /// This uses the so-called "CREATE3" workflow,
    /// which means that `pointer` is agnostic to `data, and only depends on `salt`.
    function writeDeterministic(bytes memory data, bytes32 salt)
        internal
        returns (address pointer)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let n := mload(data)
            mstore(0x00, _CREATE3_PROXY_INITCODE) // Store the `_PROXY_INITCODE`.
            let proxy := create2(0, 0x10, 0x10, salt)
            if iszero(proxy) {
                mstore(0x00, 0x30116425) // `DeploymentFailed()`.
                revert(0x1c, 0x04)
            }
            mstore(0x14, proxy) // Store the proxy's address.
            // 0xd6 = 0xc0 (short RLP prefix) + 0x16 (length of: 0x94 ++ proxy ++ 0x01).
            // 0x94 = 0x80 + 0x14 (0x14 = the length of an address, 20 bytes, in hex).
            mstore(0x00, 0xd694)
            mstore8(0x34, 0x01) // Nonce of the proxy contract (1).
            pointer := keccak256(0x1e, 0x17)

            // Do a out-of-gas revert if `n + 1` is more than 2 bytes.
            mstore(add(data, gt(n, 0xfffe)), add(0xfe61000180600a3d393df300, shl(0x40, n)))
            if iszero(
                mul( // The arguments of `mul` are evaluated last to first.
                    extcodesize(pointer),
                    call(gas(), proxy, 0, add(data, 0x15), add(n, 0xb), codesize(), 0x00)
                )
            ) {
                mstore(0x00, 0x30116425) // `DeploymentFailed()`.
                revert(0x1c, 0x04)
            }
            mstore(data, n) // Restore the length of `data`.
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                    ADDRESS CALCULATIONS                    */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns the initialization code hash of the storage contract for `data`.
    /// Used for mining vanity addresses with create2crunch.
    function initCodeHash(bytes memory data) internal pure returns (bytes32 hash) {
        /// @solidity memory-safe-assembly
        assembly {
            let n := mload(data)
            // Do a out-of-gas revert if `n + 1` is more than 2 bytes.
            returndatacopy(returndatasize(), returndatasize(), gt(n, 0xfffe))
            mstore(data, add(0x61000180600a3d393df300, shl(0x40, n)))
            hash := keccak256(add(data, 0x15), add(n, 0xb))
            mstore(data, n) // Restore the length of `data`.
        }
    }

    /// @dev Equivalent to `predictCounterfactualAddress(data, salt, address(this))`
    function predictCounterfactualAddress(bytes memory data, bytes32 salt)
        internal
        view
        returns (address pointer)
    {
        pointer = predictCounterfactualAddress(data, salt, address(this));
    }

    /// @dev Returns the CREATE2 address of the storage contract for `data`
    /// deployed with `salt` by `deployer`.
    /// Note: The returned result has dirty upper 96 bits. Please clean if used in assembly.
    function predictCounterfactualAddress(bytes memory data, bytes32 salt, address deployer)
        internal
        pure
        returns (address predicted)
    {
        bytes32 hash = initCodeHash(data);
        /// @solidity memory-safe-assembly
        assembly {
            // Compute and store the bytecode hash.
            mstore8(0x00, 0xff) // Write the prefix.
            mstore(0x35, hash)
            mstore(0x01, shl(96, deployer))
            mstore(0x15, salt)
            predicted := keccak256(0x00, 0x55)
            // Restore the part of the free memory pointer that has been overwritten.
            mstore(0x35, 0)
        }
    }

    /// @dev Equivalent to `predictDeterministicAddress(salt, address(this))`.
    function predictDeterministicAddress(bytes32 salt) internal view returns (address pointer) {
        pointer = predictDeterministicAddress(salt, address(this));
    }

    /// @dev Returns the "CREATE3" deterministic address for `salt` with `deployer`.
    function predictDeterministicAddress(bytes32 salt, address deployer)
        internal
        pure
        returns (address pointer)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let m := mload(0x40) // Cache the free memory pointer.
            mstore(0x00, deployer) // Store `deployer`.
            mstore8(0x0b, 0xff) // Store the prefix.
            mstore(0x20, salt) // Store the salt.
            mstore(0x40, CREATE3_PROXY_INITCODE_HASH) // Store the bytecode hash.

            mstore(0x14, keccak256(0x0b, 0x55)) // Store the proxy's address.
            mstore(0x40, m) // Restore the free memory pointer.
            // 0xd6 = 0xc0 (short RLP prefix) + 0x16 (length of: 0x94 ++ proxy ++ 0x01).
            // 0x94 = 0x80 + 0x14 (0x14 = the length of an address, 20 bytes, in hex).
            mstore(0x00, 0xd694)
            mstore8(0x34, 0x01) // Nonce of the proxy contract (1).
            pointer := keccak256(0x1e, 0x17)
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                         READ LOGIC                         */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Equivalent to `read(pointer, 0, 2 ** 256 - 1)`.
    function read(address pointer) internal view returns (bytes memory data) {
        /// @solidity memory-safe-assembly
        assembly {
            data := mload(0x40)
            let n := and(0xffffffffff, sub(extcodesize(pointer), 0x01))
            extcodecopy(pointer, add(data, 0x1f), 0x00, add(n, 0x21))
            mstore(data, n) // Store the length.
            mstore(0x40, add(n, add(data, 0x40))) // Allocate memory.
        }
    }

    /// @dev Equivalent to `read(pointer, start, 2 ** 256 - 1)`.
    function read(address pointer, uint256 start) internal view returns (bytes memory data) {
        /// @solidity memory-safe-assembly
        assembly {
            data := mload(0x40)
            let n := and(0xffffffffff, sub(extcodesize(pointer), 0x01))
            let l := sub(n, and(0xffffff, mul(lt(start, n), start)))
            extcodecopy(pointer, add(data, 0x1f), start, add(l, 0x21))
            mstore(data, mul(sub(n, start), lt(start, n))) // Store the length.
            mstore(0x40, add(data, add(0x40, mload(data)))) // Allocate memory.
        }
    }

    /// @dev Returns a slice of the data on `pointer` from `start` to `end`.
    /// `start` and `end` will be clamped to the range `[0, args.length]`.
    /// The `pointer` MUST be deployed via the SSTORE2 write functions.
    /// Otherwise, the behavior is undefined.
    /// Out-of-gas reverts if `pointer` does not have any code.
    function read(address pointer, uint256 start, uint256 end)
        internal
        view
        returns (bytes memory data)
    {
        /// @solidity memory-safe-assembly
        assembly {
            data := mload(0x40)
            if iszero(lt(end, 0xffff)) { end := 0xffff }
            let d := mul(sub(end, start), lt(start, end))
            extcodecopy(pointer, add(data, 0x1f), start, add(d, 0x01))
            if iszero(and(0xff, mload(add(data, d)))) {
                let n := sub(extcodesize(pointer), 0x01)
                returndatacopy(returndatasize(), returndatasize(), shr(40, n))
                d := mul(gt(n, start), sub(d, mul(gt(end, n), sub(end, n))))
            }
            mstore(data, d) // Store the length.
            mstore(add(add(data, 0x20), d), 0) // Zeroize the slot after the bytes.
            mstore(0x40, add(add(data, 0x40), d)) // Allocate memory.
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

/// @notice Simple single owner authorization mixin.
/// @author Solady (https://github.com/vectorized/solady/blob/main/src/auth/Ownable.sol)
///
/// @dev Note:
/// This implementation does NOT auto-initialize the owner to `msg.sender`.
/// You MUST call the `_initializeOwner` in the constructor / initializer.
///
/// While the ownable portion follows
/// [EIP-173](https://eips.ethereum.org/EIPS/eip-173) for compatibility,
/// the nomenclature for the 2-step ownership handover may be unique to this codebase.
abstract contract Ownable {
    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                       CUSTOM ERRORS                        */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev The caller is not authorized to call the function.
    error Unauthorized();

    /// @dev The `newOwner` cannot be the zero address.
    error NewOwnerIsZeroAddress();

    /// @dev The `pendingOwner` does not have a valid handover request.
    error NoHandoverRequest();

    /// @dev Cannot double-initialize.
    error AlreadyInitialized();

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                           EVENTS                           */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev The ownership is transferred from `oldOwner` to `newOwner`.
    /// This event is intentionally kept the same as OpenZeppelin's Ownable to be
    /// compatible with indexers and [EIP-173](https://eips.ethereum.org/EIPS/eip-173),
    /// despite it not being as lightweight as a single argument event.
    event OwnershipTransferred(address indexed oldOwner, address indexed newOwner);

    /// @dev An ownership handover to `pendingOwner` has been requested.
    event OwnershipHandoverRequested(address indexed pendingOwner);

    /// @dev The ownership handover to `pendingOwner` has been canceled.
    event OwnershipHandoverCanceled(address indexed pendingOwner);

    /// @dev `keccak256(bytes("OwnershipTransferred(address,address)"))`.
    uint256 private constant _OWNERSHIP_TRANSFERRED_EVENT_SIGNATURE =
        0x8be0079c531659141344cd1fd0a4f28419497f9722a3daafe3b4186f6b6457e0;

    /// @dev `keccak256(bytes("OwnershipHandoverRequested(address)"))`.
    uint256 private constant _OWNERSHIP_HANDOVER_REQUESTED_EVENT_SIGNATURE =
        0xdbf36a107da19e49527a7176a1babf963b4b0ff8cde35ee35d6cd8f1f9ac7e1d;

    /// @dev `keccak256(bytes("OwnershipHandoverCanceled(address)"))`.
    uint256 private constant _OWNERSHIP_HANDOVER_CANCELED_EVENT_SIGNATURE =
        0xfa7b8eab7da67f412cc9575ed43464468f9bfbae89d1675917346ca6d8fe3c92;

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                          STORAGE                           */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev The owner slot is given by:
    /// `bytes32(~uint256(uint32(bytes4(keccak256("_OWNER_SLOT_NOT")))))`.
    /// It is intentionally chosen to be a high value
    /// to avoid collision with lower slots.
    /// The choice of manual storage layout is to enable compatibility
    /// with both regular and upgradeable contracts.
    bytes32 internal constant _OWNER_SLOT =
        0xffffffffffffffffffffffffffffffffffffffffffffffffffffffff74873927;

    /// The ownership handover slot of `newOwner` is given by:
    /// ```
    ///     mstore(0x00, or(shl(96, user), _HANDOVER_SLOT_SEED))
    ///     let handoverSlot := keccak256(0x00, 0x20)
    /// ```
    /// It stores the expiry timestamp of the two-step ownership handover.
    uint256 private constant _HANDOVER_SLOT_SEED = 0x389a75e1;

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                     INTERNAL FUNCTIONS                     */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Override to return true to make `_initializeOwner` prevent double-initialization.
    function _guardInitializeOwner() internal pure virtual returns (bool guard) {}

    /// @dev Initializes the owner directly without authorization guard.
    /// This function must be called upon initialization,
    /// regardless of whether the contract is upgradeable or not.
    /// This is to enable generalization to both regular and upgradeable contracts,
    /// and to save gas in case the initial owner is not the caller.
    /// For performance reasons, this function will not check if there
    /// is an existing owner.
    function _initializeOwner(address newOwner) internal virtual {
        if (_guardInitializeOwner()) {
            /// @solidity memory-safe-assembly
            assembly {
                let ownerSlot := _OWNER_SLOT
                if sload(ownerSlot) {
                    mstore(0x00, 0x0dc149f0) // `AlreadyInitialized()`.
                    revert(0x1c, 0x04)
                }
                // Clean the upper 96 bits.
                newOwner := shr(96, shl(96, newOwner))
                // Store the new value.
                sstore(ownerSlot, or(newOwner, shl(255, iszero(newOwner))))
                // Emit the {OwnershipTransferred} event.
                log3(0, 0, _OWNERSHIP_TRANSFERRED_EVENT_SIGNATURE, 0, newOwner)
            }
        } else {
            /// @solidity memory-safe-assembly
            assembly {
                // Clean the upper 96 bits.
                newOwner := shr(96, shl(96, newOwner))
                // Store the new value.
                sstore(_OWNER_SLOT, newOwner)
                // Emit the {OwnershipTransferred} event.
                log3(0, 0, _OWNERSHIP_TRANSFERRED_EVENT_SIGNATURE, 0, newOwner)
            }
        }
    }

    /// @dev Sets the owner directly without authorization guard.
    function _setOwner(address newOwner) internal virtual {
        if (_guardInitializeOwner()) {
            /// @solidity memory-safe-assembly
            assembly {
                let ownerSlot := _OWNER_SLOT
                // Clean the upper 96 bits.
                newOwner := shr(96, shl(96, newOwner))
                // Emit the {OwnershipTransferred} event.
                log3(0, 0, _OWNERSHIP_TRANSFERRED_EVENT_SIGNATURE, sload(ownerSlot), newOwner)
                // Store the new value.
                sstore(ownerSlot, or(newOwner, shl(255, iszero(newOwner))))
            }
        } else {
            /// @solidity memory-safe-assembly
            assembly {
                let ownerSlot := _OWNER_SLOT
                // Clean the upper 96 bits.
                newOwner := shr(96, shl(96, newOwner))
                // Emit the {OwnershipTransferred} event.
                log3(0, 0, _OWNERSHIP_TRANSFERRED_EVENT_SIGNATURE, sload(ownerSlot), newOwner)
                // Store the new value.
                sstore(ownerSlot, newOwner)
            }
        }
    }

    /// @dev Throws if the sender is not the owner.
    function _checkOwner() internal view virtual {
        /// @solidity memory-safe-assembly
        assembly {
            // If the caller is not the stored owner, revert.
            if iszero(eq(caller(), sload(_OWNER_SLOT))) {
                mstore(0x00, 0x82b42900) // `Unauthorized()`.
                revert(0x1c, 0x04)
            }
        }
    }

    /// @dev Returns how long a two-step ownership handover is valid for in seconds.
    /// Override to return a different value if needed.
    /// Made internal to conserve bytecode. Wrap it in a public function if needed.
    function _ownershipHandoverValidFor() internal view virtual returns (uint64) {
        return 48 * 3600;
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                  PUBLIC UPDATE FUNCTIONS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Allows the owner to transfer the ownership to `newOwner`.
    function transferOwnership(address newOwner) public payable virtual onlyOwner {
        /// @solidity memory-safe-assembly
        assembly {
            if iszero(shl(96, newOwner)) {
                mstore(0x00, 0x7448fbae) // `NewOwnerIsZeroAddress()`.
                revert(0x1c, 0x04)
            }
        }
        _setOwner(newOwner);
    }

    /// @dev Allows the owner to renounce their ownership.
    function renounceOwnership() public payable virtual onlyOwner {
        _setOwner(address(0));
    }

    /// @dev Request a two-step ownership handover to the caller.
    /// The request will automatically expire in 48 hours (172800 seconds) by default.
    function requestOwnershipHandover() public payable virtual {
        unchecked {
            uint256 expires = block.timestamp + _ownershipHandoverValidFor();
            /// @solidity memory-safe-assembly
            assembly {
                // Compute and set the handover slot to `expires`.
                mstore(0x0c, _HANDOVER_SLOT_SEED)
                mstore(0x00, caller())
                sstore(keccak256(0x0c, 0x20), expires)
                // Emit the {OwnershipHandoverRequested} event.
                log2(0, 0, _OWNERSHIP_HANDOVER_REQUESTED_EVENT_SIGNATURE, caller())
            }
        }
    }

    /// @dev Cancels the two-step ownership handover to the caller, if any.
    function cancelOwnershipHandover() public payable virtual {
        /// @solidity memory-safe-assembly
        assembly {
            // Compute and set the handover slot to 0.
            mstore(0x0c, _HANDOVER_SLOT_SEED)
            mstore(0x00, caller())
            sstore(keccak256(0x0c, 0x20), 0)
            // Emit the {OwnershipHandoverCanceled} event.
            log2(0, 0, _OWNERSHIP_HANDOVER_CANCELED_EVENT_SIGNATURE, caller())
        }
    }

    /// @dev Allows the owner to complete the two-step ownership handover to `pendingOwner`.
    /// Reverts if there is no existing ownership handover requested by `pendingOwner`.
    function completeOwnershipHandover(address pendingOwner) public payable virtual onlyOwner {
        /// @solidity memory-safe-assembly
        assembly {
            // Compute and set the handover slot to 0.
            mstore(0x0c, _HANDOVER_SLOT_SEED)
            mstore(0x00, pendingOwner)
            let handoverSlot := keccak256(0x0c, 0x20)
            // If the handover does not exist, or has expired.
            if gt(timestamp(), sload(handoverSlot)) {
                mstore(0x00, 0x6f5e8818) // `NoHandoverRequest()`.
                revert(0x1c, 0x04)
            }
            // Set the handover slot to 0.
            sstore(handoverSlot, 0)
        }
        _setOwner(pendingOwner);
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   PUBLIC READ FUNCTIONS                    */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns the owner of the contract.
    function owner() public view virtual returns (address result) {
        /// @solidity memory-safe-assembly
        assembly {
            result := sload(_OWNER_SLOT)
        }
    }

    /// @dev Returns the expiry timestamp for the two-step ownership handover to `pendingOwner`.
    function ownershipHandoverExpiresAt(address pendingOwner)
        public
        view
        virtual
        returns (uint256 result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            // Compute the handover slot.
            mstore(0x0c, _HANDOVER_SLOT_SEED)
            mstore(0x00, pendingOwner)
            // Load the handover slot.
            result := sload(keccak256(0x0c, 0x20))
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                         MODIFIERS                          */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Marks a function as only callable by the owner.
    modifier onlyOwner() virtual {
        _checkOwner();
        _;
    }
}