Dnner

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

/// @notice Library to encode strings in Base64.
/// @author Solady (https://github.com/vectorized/solady/blob/main/src/utils/Base64.sol)
/// @author Modified from Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/Base64.sol)
/// @author Modified from (https://github.com/Brechtpd/base64/blob/main/base64.sol) by Brecht Devos - <brecht@loopring.org>.
library Base64 {
    /// @dev Encodes `data` using the base64 encoding described in RFC 4648.
    /// See: https://datatracker.ietf.org/doc/html/rfc4648
    /// @param fileSafe  Whether to replace '+' with '-' and '/' with '_'.
    /// @param noPadding Whether to strip away the padding.
    function encode(bytes memory data, bool fileSafe, bool noPadding)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let dataLength := mload(data)

            if dataLength {
                // Multiply by 4/3 rounded up.
                // The `shl(2, ...)` is equivalent to multiplying by 4.
                let encodedLength := shl(2, div(add(dataLength, 2), 3))

                // Set `result` to point to the start of the free memory.
                result := mload(0x40)

                // Store the table into the scratch space.
                // Offsetted by -1 byte so that the `mload` will load the character.
                // We will rewrite the free memory pointer at `0x40` later with
                // the allocated size.
                // The magic constant 0x0670 will turn "-_" into "+/".
                mstore(0x1f, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdef")
                mstore(0x3f, xor("ghijklmnopqrstuvwxyz0123456789-_", mul(iszero(fileSafe), 0x0670)))

                // Skip the first slot, which stores the length.
                let ptr := add(result, 0x20)
                let end := add(ptr, encodedLength)

                // Run over the input, 3 bytes at a time.
                for {} 1 {} {
                    data := add(data, 3) // Advance 3 bytes.
                    let input := mload(data)

                    // Write 4 bytes. Optimized for fewer stack operations.
                    mstore8(0, mload(and(shr(18, input), 0x3F)))
                    mstore8(1, mload(and(shr(12, input), 0x3F)))
                    mstore8(2, mload(and(shr(6, input), 0x3F)))
                    mstore8(3, mload(and(input, 0x3F)))
                    mstore(ptr, mload(0x00))

                    ptr := add(ptr, 4) // Advance 4 bytes.
                    if iszero(lt(ptr, end)) { break }
                }
                mstore(0x40, add(end, 0x20)) // Allocate the memory.
                // Equivalent to `o = [0, 2, 1][dataLength % 3]`.
                let o := div(2, mod(dataLength, 3))
                // Offset `ptr` and pad with '='. We can simply write over the end.
                mstore(sub(ptr, o), shl(240, 0x3d3d))
                // Set `o` to zero if there is padding.
                o := mul(iszero(iszero(noPadding)), o)
                mstore(sub(ptr, o), 0) // Zeroize the slot after the string.
                mstore(result, sub(encodedLength, o)) // Store the length.
            }
        }
    }

    /// @dev Encodes `data` using the base64 encoding described in RFC 4648.
    /// Equivalent to `encode(data, false, false)`.
    function encode(bytes memory data) internal pure returns (string memory result) {
        result = encode(data, false, false);
    }

    /// @dev Encodes `data` using the base64 encoding described in RFC 4648.
    /// Equivalent to `encode(data, fileSafe, false)`.
    function encode(bytes memory data, bool fileSafe)
        internal
        pure
        returns (string memory result)
    {
        result = encode(data, fileSafe, false);
    }

    /// @dev Decodes base64 encoded `data`.
    ///
    /// Supports:
    /// - RFC 4648 (both standard and file-safe mode).
    /// - RFC 3501 (63: ',').
    ///
    /// Does not support:
    /// - Line breaks.
    ///
    /// Note: For performance reasons,
    /// this function will NOT revert on invalid `data` inputs.
    /// Outputs for invalid inputs will simply be undefined behaviour.
    /// It is the user's responsibility to ensure that the `data`
    /// is a valid base64 encoded string.
    function decode(string memory data) internal pure returns (bytes memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            let dataLength := mload(data)

            if dataLength {
                let decodedLength := mul(shr(2, dataLength), 3)

                for {} 1 {} {
                    // If padded.
                    if iszero(and(dataLength, 3)) {
                        let t := xor(mload(add(data, dataLength)), 0x3d3d)
                        // forgefmt: disable-next-item
                        decodedLength := sub(
                            decodedLength,
                            add(iszero(byte(30, t)), iszero(byte(31, t)))
                        )
                        break
                    }
                    // If non-padded.
                    decodedLength := add(decodedLength, sub(and(dataLength, 3), 1))
                    break
                }
                result := mload(0x40)

                // Write the length of the bytes.
                mstore(result, decodedLength)

                // Skip the first slot, which stores the length.
                let ptr := add(result, 0x20)
                let end := add(ptr, decodedLength)

                // Load the table into the scratch space.
                // Constants are optimized for smaller bytecode with zero gas overhead.
                // `m` also doubles as the mask of the upper 6 bits.
                let m := 0xfc000000fc00686c7074787c8084888c9094989ca0a4a8acb0b4b8bcc0c4c8cc
                mstore(0x5b, m)
                mstore(0x3b, 0x04080c1014181c2024282c3034383c4044484c5054585c6064)
                mstore(0x1a, 0xf8fcf800fcd0d4d8dce0e4e8ecf0f4)

                for {} 1 {} {
                    // Read 4 bytes.
                    data := add(data, 4)
                    let input := mload(data)

                    // Write 3 bytes.
                    // forgefmt: disable-next-item
                    mstore(ptr, or(
                        and(m, mload(byte(28, input))),
                        shr(6, or(
                            and(m, mload(byte(29, input))),
                            shr(6, or(
                                and(m, mload(byte(30, input))),
                                shr(6, mload(byte(31, input)))
                            ))
                        ))
                    ))
                    ptr := add(ptr, 3)
                    if iszero(lt(ptr, end)) { break }
                }
                mstore(0x40, add(end, 0x20)) // Allocate the memory.
                mstore(end, 0) // Zeroize the slot after the bytes.
                mstore(0x60, 0) // Restore the zero slot.
            }
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;
/// @dev Dnner Note:
/// - Dnner(DN404ND) does not possess the fragmentability, nor does 
///   it have the feature of NFT transactions without the 
///   need for a third party, characteristic of ERC404/DN404. 
///   
///   DN404 can easily create efficient hybrid tokens and 
///   define the ratio between NFT and tokens. 
///   We aim to leverage the foundation of DN404 to enable
///   NFT to drive the increase in token value.
///  
///   Another way of putting it is to avoid turning NFTs 
///   into purely tokenized assets. 
///  
///   This is an experimental project not conforming to 
///   the 404 standard, DYOR and read more from our website.
///
///   Twitter: https://twitter.com/DN404ND
///   Website: https://dnner.shop

/// @title DN404Mirror
/// @notice DN404Mirror provides an interface for interacting with the
/// NFT tokens in a DN404 implementation.
///
/// @author vectorized.eth (@optimizoor)
/// @author Quit (@0xQuit)
/// @author Michael Amadi (@AmadiMichaels)
/// @author cygaar (@0xCygaar)
/// @author Thomas (@0xjustadev)
/// @author Harrison (@PopPunkOnChain)
///
/// @dev Note:
/// - The ERC721 data is stored in the base DN404 contract.
contract DN404Mirror {
    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                           EVENTS                           */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Emitted when token `id` is transferred from `from` to `to`.
    event Transfer(address indexed from, address indexed to, uint256 indexed id);

    /// @dev Emitted when `owner` enables `account` to manage the `id` token.
    event Approval(address indexed owner, address indexed account, uint256 indexed id);

    /// @dev Emitted when `owner` enables or disables `operator` to manage all of their tokens.
    event ApprovalForAll(address indexed owner, address indexed operator, bool isApproved);

    /// @dev The ownership is transferred from `oldOwner` to `newOwner`.
    /// This is for marketplace signaling purposes. This contract has a `pullOwner()`
    /// function that will sync the owner from the base contract.
    event OwnershipTransferred(address indexed oldOwner, address indexed newOwner);

    /// @dev `keccak256(bytes("Transfer(address,address,uint256)"))`.
    uint256 private constant _TRANSFER_EVENT_SIGNATURE =
        0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef;

    /// @dev `keccak256(bytes("Approval(address,address,uint256)"))`.
    uint256 private constant _APPROVAL_EVENT_SIGNATURE =
        0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925;

    /// @dev `keccak256(bytes("ApprovalForAll(address,address,bool)"))`.
    uint256 private constant _APPROVAL_FOR_ALL_EVENT_SIGNATURE =
        0x17307eab39ab6107e8899845ad3d59bd9653f200f220920489ca2b5937696c31;

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                        CUSTOM ERRORS                       */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Thrown when a call for an NFT function did not originate
    /// from the base DN404 contract.
    error SenderNotBase();

    /// @dev Thrown when a call for an NFT function did not originate from the deployer.
    error SenderNotDeployer();

    /// @dev Thrown when transferring an NFT to a contract address that
    /// does not implement ERC721Receiver.
    error TransferToNonERC721ReceiverImplementer();

    /// @dev Thrown when linking to the DN404 base contract and the
    /// DN404 supportsInterface check fails or the call reverts.
    error CannotLink();

    /// @dev Thrown when a linkMirrorContract call is received and the
    /// NFT mirror contract has already been linked to a DN404 base contract.
    error AlreadyLinked();

    /// @dev Thrown when retrieving the base DN404 address when a link has not
    /// been established.
    error NotLinked();

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                          STORAGE                           */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Struct contain the NFT mirror contract storage.
    struct DN404NFTStorage {
        address baseERC20;
        address deployer;
        address owner;
    }

    /// @dev Returns a storage pointer for DN404NFTStorage.
    function _getDN404NFTStorage() internal pure virtual returns (DN404NFTStorage storage $) {
        /// @solidity memory-safe-assembly
        assembly {
            // `uint72(bytes9(keccak256("DN404_MIRROR_STORAGE")))`.
            $.slot := 0x3602298b8c10b01230 // Truncate to 9 bytes to reduce bytecode size.
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                        CONSTRUCTOR                         */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    constructor(address deployer) {
        // For non-proxies, we will store the deployer so that only the deployer can
        // link the base contract.
        _getDN404NFTStorage().deployer = deployer;
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                     ERC721 OPERATIONS                      */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Returns the token collection name from the base DN404 contract.
    function name() public view virtual returns (string memory result) {
        return _readString(0x06fdde03, 0); // `name()`.
    }

    /// @dev Returns the token collection symbol from the base DN404 contract.
    function symbol() public view virtual returns (string memory result) {
        return _readString(0x95d89b41, 0); // `symbol()`.
    }

    /// @dev Returns the Uniform Resource Identifier (URI) for token `id` from
    /// the base DN404 contract.
    function tokenURI(uint256 id) public view virtual returns (string memory result) {
        return _readString(0xc87b56dd, id); // `tokenURI()`.
    }

    /// @dev Returns the total NFT supply from the base DN404 contract.
    function totalSupply() public view virtual returns (uint256 result) {
        return _readWord(0xe2c79281, 0, 0); // `totalNFTSupply()`.
    }

    /// @dev Returns the number of NFT tokens owned by `nftOwner` from the base DN404 contract.
    ///
    /// Requirements:
    /// - `nftOwner` must not be the zero address.
    function balanceOf(address nftOwner) public view virtual returns (uint256 result) {
        return _readWord(0xf5b100ea, uint160(nftOwner), 0); // `balanceOfNFT(address)`.
    }

    /// @dev Returns the owner of token `id` from the base DN404 contract.
    ///
    /// Requirements:
    /// - Token `id` must exist.
    function ownerOf(uint256 id) public view virtual returns (address result) {
        return address(uint160(_readWord(0x6352211e, id, 0))); // `ownerOf(uint256)`.
    }

    /// @dev Returns the owner of token `id` from the base DN404 contract.
    /// Returns `address(0)` instead of reverting if the token does not exist.
    function ownerAt(uint256 id) public view virtual returns (address result) {
        return address(uint160(_readWord(0x24359879, id, 0))); // `ownerAt(uint256)`.
    }

    /// @dev Sets `spender` as the approved account to manage token `id` in
    /// the base DN404 contract.
    ///
    /// Requirements:
    /// - Token `id` must exist.
    /// - The caller must be the owner of the token,
    ///   or an approved operator for the token owner.
    ///
    /// Emits an {Approval} event.
    function approve(address spender, uint256 id) public virtual {
        address base = baseERC20();
        /// @solidity memory-safe-assembly
        assembly {
            spender := shr(96, shl(96, spender))
            let m := mload(0x40)
            mstore(0x00, 0xd10b6e0c) // `approveNFT(address,uint256,address)`.
            mstore(0x20, spender)
            mstore(0x40, id)
            mstore(0x60, caller())
            if iszero(
                and(
                    gt(returndatasize(), 0x1f),
                    call(gas(), base, callvalue(), 0x1c, 0x64, 0x00, 0x20)
                )
            ) {
                returndatacopy(m, 0x00, returndatasize())
                revert(m, returndatasize())
            }
            mstore(0x40, m) // Restore the free memory pointer.
            mstore(0x60, 0) // Restore the zero pointer.
            // Emit the {Approval} event.
            log4(codesize(), 0x00, _APPROVAL_EVENT_SIGNATURE, shr(96, mload(0x0c)), spender, id)
        }
    }

    /// @dev Returns the account approved to manage token `id` from
    /// the base DN404 contract.
    ///
    /// Requirements:
    /// - Token `id` must exist.
    function getApproved(uint256 id) public view virtual returns (address) {
        return address(uint160(_readWord(0x081812fc, id, 0))); // `getApproved(uint256)`.
    }

    /// @dev Sets whether `operator` is approved to manage the tokens of the caller in
    /// the base DN404 contract.
    ///
    /// Emits an {ApprovalForAll} event.
    function setApprovalForAll(address operator, bool approved) public virtual {
        address base = baseERC20();
        /// @solidity memory-safe-assembly
        assembly {
            operator := shr(96, shl(96, operator))
            let m := mload(0x40)
            mstore(0x00, 0x813500fc) // `setApprovalForAll(address,bool,address)`.
            mstore(0x20, operator)
            mstore(0x40, iszero(iszero(approved)))
            mstore(0x60, caller())
            if iszero(
                and(eq(mload(0x00), 1), call(gas(), base, callvalue(), 0x1c, 0x64, 0x00, 0x20))
            ) {
                returndatacopy(m, 0x00, returndatasize())
                revert(m, returndatasize())
            }
            // Emit the {ApprovalForAll} event.
            // The `approved` value is already at 0x40.
            log3(0x40, 0x20, _APPROVAL_FOR_ALL_EVENT_SIGNATURE, caller(), operator)
            mstore(0x40, m) // Restore the free memory pointer.
            mstore(0x60, 0) // Restore the zero pointer.
        }
    }

    /// @dev Returns whether `operator` is approved to manage the tokens of `nftOwner` from
    /// the base DN404 contract.
    function isApprovedForAll(address nftOwner, address operator)
        public
        view
        virtual
        returns (bool result)
    {
        // `isApprovedForAll(address,address)`.
        return _readWord(0xe985e9c5, uint160(nftOwner), uint160(operator)) != 0;
    }

    /// @dev Transfers token `id` from `from` to `to`.
    ///
    /// Requirements:
    ///
    /// - Token `id` must exist.
    /// - `from` must be the owner of the token.
    /// - `to` cannot be the zero address.
    /// - The caller must be the owner of the token, or be approved to manage the token.
    ///
    /// Emits a {Transfer} event.
    function transferFrom(address from, address to, uint256 id) public virtual {
        address base = baseERC20();
        /// @solidity memory-safe-assembly
        assembly {
            from := shr(96, shl(96, from))
            to := shr(96, shl(96, to))
            let m := mload(0x40)
            mstore(m, 0xe5eb36c8) // `transferFromNFT(address,address,uint256,address)`.
            mstore(add(m, 0x20), from)
            mstore(add(m, 0x40), to)
            mstore(add(m, 0x60), id)
            mstore(add(m, 0x80), caller())
            if iszero(
                and(eq(mload(m), 1), call(gas(), base, callvalue(), add(m, 0x1c), 0x84, m, 0x20))
            ) {
                returndatacopy(m, 0x00, returndatasize())
                revert(m, returndatasize())
            }
            // Emit the {Transfer} event.
            log4(codesize(), 0x00, _TRANSFER_EVENT_SIGNATURE, from, to, id)
        }
    }

    /// @dev Equivalent to `safeTransferFrom(from, to, id, "")`.
    function safeTransferFrom(address from, address to, uint256 id) public payable virtual {
        transferFrom(from, to, id);

        if (_hasCode(to)) _checkOnERC721Received(from, to, id, "");
    }

    /// @dev Transfers token `id` from `from` to `to`.
    ///
    /// Requirements:
    ///
    /// - Token `id` must exist.
    /// - `from` must be the owner of the token.
    /// - `to` cannot be the zero address.
    /// - The caller must be the owner of the token, or be approved to manage the token.
    /// - If `to` refers to a smart contract, it must implement
    ///   {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
    ///
    /// Emits a {Transfer} event.
    function safeTransferFrom(address from, address to, uint256 id, bytes calldata data)
        public
        virtual
    {
        transferFrom(from, to, id);

        if (_hasCode(to)) _checkOnERC721Received(from, to, id, data);
    }

    /// @dev Returns true if this contract implements the interface defined by `interfaceId`.
    /// See: https://eips.ethereum.org/EIPS/eip-165
    /// This function call must use less than 30000 gas.
    function supportsInterface(bytes4 interfaceId) public view virtual returns (bool result) {
        /// @solidity memory-safe-assembly
        assembly {
            let s := shr(224, interfaceId)
            // ERC165: 0x01ffc9a7, ERC721: 0x80ac58cd, ERC721Metadata: 0x5b5e139f.
            result := or(or(eq(s, 0x01ffc9a7), eq(s, 0x80ac58cd)), eq(s, 0x5b5e139f))
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                  OWNER SYNCING OPERATIONS                  */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Returns the `owner` of the contract, for marketplace signaling purposes.
    function owner() public view virtual returns (address) {
        return _getDN404NFTStorage().owner;
    }

    /// @dev Permissionless function to pull the owner from the base DN404 contract
    /// if it implements ownable, for marketplace signaling purposes.
    function pullOwner() public virtual {
        address newOwner;
        address base = baseERC20();
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, 0x8da5cb5b) // `owner()`.
            if and(gt(returndatasize(), 0x1f), staticcall(gas(), base, 0x1c, 0x04, 0x00, 0x20)) {
                newOwner := shr(96, mload(0x0c))
            }
        }
        DN404NFTStorage storage $ = _getDN404NFTStorage();
        address oldOwner = $.owner;
        if (oldOwner != newOwner) {
            $.owner = newOwner;
            emit OwnershipTransferred(oldOwner, newOwner);
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                     MIRROR OPERATIONS                      */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Returns the address of the base DN404 contract.
    function baseERC20() public view virtual returns (address base) {
        base = _getDN404NFTStorage().baseERC20;
        if (base == address(0)) revert NotLinked();
    }

    /// @dev Fallback modifier to execute calls from the base DN404 contract.
    modifier dn404NFTFallback() virtual {
        DN404NFTStorage storage $ = _getDN404NFTStorage();

        uint256 fnSelector = _calldataload(0x00) >> 224;

        // `logTransfer(uint256[])`.
        if (fnSelector == 0x263c69d6) {
            if (msg.sender != $.baseERC20) revert SenderNotBase();
            /// @solidity memory-safe-assembly
            assembly {
                // When returndatacopy copies 1 or more out-of-bounds bytes, it reverts.
                returndatacopy(0x00, returndatasize(), lt(calldatasize(), 0x20))
                let o := add(0x24, calldataload(0x04)) // Packed logs offset.
                returndatacopy(0x00, returndatasize(), lt(calldatasize(), o))
                let end := add(o, shl(5, calldataload(sub(o, 0x20))))
                returndatacopy(0x00, returndatasize(), lt(calldatasize(), end))

                for {} iszero(eq(o, end)) { o := add(0x20, o) } {
                    let d := calldataload(o) // Entry in the packed logs.
                    let a := shr(96, d) // The address.
                    let b := and(1, d) // Whether it is a burn.
                    log4(
                        codesize(),
                        0x00,
                        _TRANSFER_EVENT_SIGNATURE,
                        mul(a, b), // `from`.
                        mul(a, iszero(b)), // `to`.
                        shr(168, shl(160, d)) // `id`.
                    )
                }
                mstore(0x00, 0x01)
                return(0x00, 0x20)
            }
        }
        // `linkMirrorContract(address)`.
        if (fnSelector == 0x0f4599e5) {
            if ($.deployer != address(0)) {
                if (address(uint160(_calldataload(0x04))) != $.deployer) {
                    revert SenderNotDeployer();
                }
            }
            if ($.baseERC20 != address(0)) revert AlreadyLinked();
            $.baseERC20 = msg.sender;
            /// @solidity memory-safe-assembly
            assembly {
                mstore(0x00, 0x01)
                return(0x00, 0x20)
            }
        }
        _;
    }

    /// @dev Fallback function for calls from base DN404 contract.
    fallback() external payable virtual dn404NFTFallback {}

    receive() external payable virtual {}

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                      PRIVATE HELPERS                       */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Helper to read a string from the base DN404 contract.
    function _readString(uint256 fnSelector, uint256 arg0)
        private
        view
        returns (string memory result)
    {
        address base = baseERC20();
        /// @solidity memory-safe-assembly
        assembly {
            result := mload(0x40)
            mstore(0x00, fnSelector)
            mstore(0x20, arg0)
            if iszero(staticcall(gas(), base, 0x1c, 0x24, 0x00, 0x00)) {
                returndatacopy(result, 0x00, returndatasize())
                revert(result, returndatasize())
            }
            returndatacopy(0x00, 0x00, 0x20) // Copy the offset of the string in returndata.
            returndatacopy(result, mload(0x00), 0x20) // Copy the length of the string.
            returndatacopy(add(result, 0x20), add(mload(0x00), 0x20), mload(result)) // Copy the string.
            mstore(0x40, add(add(result, 0x20), mload(result))) // Allocate memory.
        }
    }

    /// @dev Helper to read a word from the base DN404 contract.
    function _readWord(uint256 fnSelector, uint256 arg0, uint256 arg1)
        private
        view
        returns (uint256 result)
    {
        address base = baseERC20();
        /// @solidity memory-safe-assembly
        assembly {
            let m := mload(0x40)
            mstore(0x00, fnSelector)
            mstore(0x20, arg0)
            mstore(0x40, arg1)
            if iszero(
                and(gt(returndatasize(), 0x1f), staticcall(gas(), base, 0x1c, 0x44, 0x00, 0x20))
            ) {
                returndatacopy(m, 0x00, returndatasize())
                revert(m, returndatasize())
            }
            mstore(0x40, m) // Restore the free memory pointer.
            result := mload(0x00)
        }
    }

    /// @dev Returns the calldata value at `offset`.
    function _calldataload(uint256 offset) private pure returns (uint256 value) {
        /// @solidity memory-safe-assembly
        assembly {
            value := calldataload(offset)
        }
    }

    /// @dev Returns if `a` has bytecode of non-zero length.
    function _hasCode(address a) private view returns (bool result) {
        /// @solidity memory-safe-assembly
        assembly {
            result := extcodesize(a) // Can handle dirty upper bits.
        }
    }

    /// @dev Perform a call to invoke {IERC721Receiver-onERC721Received} on `to`.
    /// Reverts if the target does not support the function correctly.
    function _checkOnERC721Received(address from, address to, uint256 id, bytes memory data)
        private
    {
        /// @solidity memory-safe-assembly
        assembly {
            // Prepare the calldata.
            let m := mload(0x40)
            let onERC721ReceivedSelector := 0x150b7a02
            mstore(m, onERC721ReceivedSelector)
            mstore(add(m, 0x20), caller()) // The `operator`, which is always `msg.sender`.
            mstore(add(m, 0x40), shr(96, shl(96, from)))
            mstore(add(m, 0x60), id)
            mstore(add(m, 0x80), 0x80)
            let n := mload(data)
            mstore(add(m, 0xa0), n)
            if n { pop(staticcall(gas(), 4, add(data, 0x20), n, add(m, 0xc0), n)) }
            // Revert if the call reverts.
            if iszero(call(gas(), to, 0, add(m, 0x1c), add(n, 0xa4), m, 0x20)) {
                if returndatasize() {
                    // Bubble up the revert if the call reverts.
                    returndatacopy(m, 0x00, returndatasize())
                    revert(m, returndatasize())
                }
            }
            // Load the returndata and compare it.
            if iszero(eq(mload(m), shl(224, onERC721ReceivedSelector))) {
                mstore(0x00, 0xd1a57ed6) // `TransferToNonERC721ReceiverImplementer()`.
                revert(0x1c, 0x04)
            }
        }
    }
}

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

/// @dev Dnner Note:
/// - Dnner(DN404ND) does not possess the fragmentability, nor does
///   it have the feature of NFT transactions without the
///   need for a third party, characteristic of ERC404/DN404.
///
///   DN404 can easily create efficient hybrid tokens and
///   define the ratio between NFT and tokens.
///   We aim to leverage the foundation of DN404 to enable
///   NFT to drive the increase in token value.
///
///   Another way of putting it is to avoid turning NFTs
///   into purely tokenized assets.
///
///   This is an experimental project not conforming to
///   the 404 standard, DYOR and read more from our website.
///
///   Twitter: https://twitter.com/DN404ND
///   Website: https://dnner.shop

/// @title DN404
/// @notice DN404 is a hybrid ERC20 and ERC721 implementation that mints
/// and burns NFTs based on an account's ERC20 token balance.
///
/// @author vectorized.eth (@optimizoor)
/// @author Quit (@0xQuit)
/// @author Michael Amadi (@AmadiMichaels)
/// @author cygaar (@0xCygaar)
/// @author Thomas (@0xjustadev)
/// @author Harrison (@PopPunkOnChain)
///
/// @dev Note:
/// - The ERC721 data is stored in this base DN404 contract, however a
///   DN404Mirror contract ***MUST*** be deployed and linked during
///   initialization.
///

abstract contract DN404ND {
    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                           EVENTS                           */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Emitted when `amount` tokens is transferred from `from` to `to`.
    event Transfer(address indexed from, address indexed to, uint256 amount);

    /// @dev Emitted when `amount` tokens is approved by `owner` to be used by `spender`.
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 amount
    );

    /// @dev Emitted when `target` sets their skipNFT flag to `status`.
    event SkipNFTSet(address indexed target, bool status);

    /// @dev `keccak256(bytes("Transfer(address,address,uint256)"))`.
    uint256 private constant _TRANSFER_EVENT_SIGNATURE =
        0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef;

    /// @dev `keccak256(bytes("Approval(address,address,uint256)"))`.
    uint256 private constant _APPROVAL_EVENT_SIGNATURE =
        0x8c5be1e5ebec7d5bd14f71427d1e84f3dd0314c0f7b2291e5b200ac8c7c3b925;

    /// @dev `keccak256(bytes("SkipNFTSet(address,bool)"))`.
    uint256 private constant _SKIP_NFT_SET_EVENT_SIGNATURE =
        0xb5a1de456fff688115a4f75380060c23c8532d14ff85f687cc871456d6420393;

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                        CUSTOM ERRORS                       */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Thrown when attempting to double-initialize the contract.
    error DNAlreadyInitialized();

    /// @dev Thrown when attempting to transfer or burn more tokens than sender's balance.
    error InsufficientBalance();

    /// @dev Thrown when a spender attempts to transfer tokens with an insufficient allowance.
    error InsufficientAllowance();

    /// @dev Thrown when minting an amount of tokens that would overflow the max tokens.
    error TotalSupplyOverflow();

    /// @dev The unit cannot be zero.
    error UnitIsZero();

    /// @dev Thrown when the caller for a fallback NFT function is not the mirror contract.
    error SenderNotMirror();

    /// @dev Thrown when attempting to transfer tokens to the zero address.
    error TransferToZeroAddress();

    /// @dev Thrown when the mirror address provided for initialization is the zero address.
    error MirrorAddressIsZero();

    /// @dev Thrown when the link call to the mirror contract reverts.
    error LinkMirrorContractFailed();

    /// @dev Thrown when setting an NFT token approval
    /// and the caller is not the owner or an approved operator.
    error ApprovalCallerNotOwnerNorApproved();

    /// @dev Thrown when transferring an NFT
    /// and the caller is not the owner or an approved operator.
    error TransferCallerNotOwnerNorApproved();

    /// @dev Thrown when transferring an NFT and the from address is not the current owner.
    error TransferFromIncorrectOwner();

    /// @dev Thrown when checking the owner or approved address for a non-existent NFT.
    error TokenDoesNotExist();

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                         CONSTANTS                          */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev The flag to denote that the address data is initialized.
    uint8 internal constant _ADDRESS_DATA_INITIALIZED_FLAG = 1 << 0;

    /// @dev The flag to denote that the address should skip NFTs.
    uint8 internal constant _ADDRESS_DATA_SKIP_NFT_FLAG = 1 << 1;

    /// @dev The flag to denote that the address has overridden the default Permit2 allowance.
    uint8 internal constant _ADDRESS_DATA_OVERRIDE_PERMIT2_FLAG = 1 << 2;

    /// @dev The canonical Permit2 address.
    /// For signature-based allowance granting for single transaction ERC20 `transferFrom`.
    /// To enable, override `_givePermit2DefaultInfiniteAllowance()`.
    /// [Github](https://github.com/Uniswap/permit2)
    /// [Etherscan](https://etherscan.io/address/0x000000000022D473030F116dDEE9F6B43aC78BA3)
    address internal constant _PERMIT2 =
        0x000000000022D473030F116dDEE9F6B43aC78BA3;

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                          STORAGE                           */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Struct containing an address's token data and settings.
    struct AddressData {
        // Flags for `initialized` and `skipNFT`.
        uint8 flags;
        // The alias for the address. Zero means absence of an alias.
        uint32 addressAlias;
        // The number of NFT tokens.
        uint32 ownedLength;
        // The token balance in wei.
        uint96 balance;
        //
        // Lock the token balance from received(NFT) or mint(NFT) to prevent
        // from being mistakenly transferred, which could lead to
        // NFT transaction errors. You can use unlock to release them,
        // which will also destroy a corresponding amount of NFTs.
        //
        // These tokens will be deducted when the NFT is transferred
        // and increased when the NFT is received.
        uint96 lockedBalance;
    }

    /// @dev A uint32 map in storage.
    struct Uint32Map {
        uint256 spacer;
    }

    /// @dev A uint32 map in storage.
    struct Uint256Map {
        uint256 spacer;
    }

    /// @dev A bitmap in storage.
    struct Bitmap {
        uint256 spacer;
    }

    /// @dev A struct to wrap a uint256 in storage.
    struct Uint256Ref {
        uint256 value;
    }

    /// @dev A mapping of an address pair to a Uint256Ref.
    struct AddressPairToUint256RefMap {
        uint256 spacer;
    }

    /// @dev Struct containing the base token contract storage.
    struct DN404Storage {
        // Current number of address aliases assigned.
        uint32 numAliases;
        // Next NFT ID to assign for a mint.
        uint32 nextTokenId;
        // Total number of NFT IDs in the burned pool.
        uint32 burnedPoolSize;
        // Total supply of minted NFTs.
        uint32 totalNFTSupply;
        // Max NFT supply.
        uint256 maxNFTSupply;
        // Total supply of tokens.
        uint96 totalSupply;
        // Address of the NFT mirror contract.
        address mirrorERC721;
        // Mapping of a user alias number to their address.
        mapping(uint32 => address) aliasToAddress;
        // Mapping of user operator approvals for NFTs.
        AddressPairToUint256RefMap operatorApprovals;
        // Mapping of NFT approvals to approved operators.
        mapping(uint256 => address) nftApprovals;
        // Bitmap of whether an non-zero NFT approval may exist.
        Bitmap mayHaveNFTApproval;
        // Mapping of user allowances for ERC20 spenders.
        AddressPairToUint256RefMap allowance;
        // Mapping of NFT IDs owned by an address.
        mapping(address => Uint32Map) owned;
        // The pool of burned NFT IDs.
        Uint32Map burnedPool;
        // Even indices: owner aliases. Odd indices: owned indices.
        Uint32Map oo;
        // Mapping of user account AddressData.
        mapping(address => AddressData) addressData;
        // Mapping of nftID to check last value(unit).
        Uint256Map NFTUnit;
    }

    /// @dev Returns a storage pointer for DN404Storage.
    function _getDN404Storage()
        internal
        pure
        virtual
        returns (DN404Storage storage $)
    {
        /// @solidity memory-safe-assembly
        assembly {
            // `uint72(bytes9(keccak256("DN404_STORAGE")))`.
            $.slot := 0xa20d6e21d0e5255308 // Truncate to 9 bytes to reduce bytecode size.
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                         INITIALIZER                        */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Initializes the DN404 contract with an
    /// `initialTokenSupply`, `initialTokenOwner` and `mirror` NFT contract address.
    function _initializeDN404(
        uint256 initialTokenSupply,
        address initialSupplyOwner,
        address mirror
    ) internal virtual {
        DN404Storage storage $ = _getDN404Storage();

        if ($.nextTokenId != 0) revert DNAlreadyInitialized();

        if (mirror == address(0)) revert MirrorAddressIsZero();

        /// @solidity memory-safe-assembly
        assembly {
            // Make the call to link the mirror contract.
            mstore(0x00, 0x0f4599e5) // `linkMirrorContract(address)`.
            mstore(0x20, caller())
            if iszero(
                and(
                    eq(mload(0x00), 1),
                    call(gas(), mirror, 0, 0x1c, 0x24, 0x00, 0x20)
                )
            ) {
                mstore(0x00, 0xd125259c) // `LinkMirrorContractFailed()`.
                revert(0x1c, 0x04)
            }
        }

        $.nextTokenId = 1;
        $.mirrorERC721 = mirror;

        if (_unit() == 0) revert UnitIsZero();

        if (initialTokenSupply != 0) {
            if (initialSupplyOwner == address(0))
                revert TransferToZeroAddress();
            if (_totalSupplyOverflows(initialTokenSupply))
                revert TotalSupplyOverflow();

            $.totalSupply = uint96(initialTokenSupply);
            AddressData storage initialOwnerAddressData = _addressData(
                initialSupplyOwner
            );
            initialOwnerAddressData.balance = uint96(initialTokenSupply);

            /// @solidity memory-safe-assembly
            assembly {
                // Emit the {Transfer} event.
                mstore(0x00, initialTokenSupply)
                log3(
                    0x00,
                    0x20,
                    _TRANSFER_EVENT_SIGNATURE,
                    0,
                    shr(96, shl(96, initialSupplyOwner))
                )
            }
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*               BASE UNIT FUNCTION TO OVERRIDE               */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Amount of token balance that is equal to one NFT.
    function _unit() internal view virtual returns (uint256) {
        return 10**18;
    }

    function _NFTUnit() internal view virtual returns (uint256) {
        return 10**18;
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*               METADATA FUNCTIONS TO OVERRIDE               */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Returns the name of the token.
    function name() public view virtual returns (string memory);

    /// @dev Returns the symbol of the token.
    function symbol() public view virtual returns (string memory);

    /// @dev Returns the Uniform Resource Identifier (URI) for token `id`.
    function tokenURI(uint256 id) public view virtual returns (string memory);

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                      ERC20 OPERATIONS                      */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Returns the decimals places of the token. Always 18.
    function decimals() public pure returns (uint8) {
        return 18;
    }

    /// @dev Returns the amount of tokens in existence.
    function totalSupply() public view virtual returns (uint256) {
        return uint256(_getDN404Storage().totalSupply);
    }

    /// @dev Returns the amount of tokens owned by `owner`.
    function balanceOf(address owner) public view virtual returns (uint256) {
        return _getDN404Storage().addressData[owner].balance;
    }

    /// @dev Returns the amount of tokens that `spender` can spend on behalf of `owner`.
    function allowance(address owner, address spender)
        public
        view
        returns (uint256)
    {
        if (_givePermit2DefaultInfiniteAllowance() && spender == _PERMIT2) {
            uint8 flags = _getDN404Storage().addressData[owner].flags;
            if (flags & _ADDRESS_DATA_OVERRIDE_PERMIT2_FLAG == 0)
                return type(uint256).max;
        }
        return _ref(_getDN404Storage().allowance, owner, spender).value;
    }

    /// @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
    ///
    /// Emits a {Approval} event.
    function approve(address spender, uint256 amount)
        public
        virtual
        returns (bool)
    {
        _approve(msg.sender, spender, amount);
        return true;
    }

    /// @dev Transfer `amount` tokens from the caller to `to`.
    ///
    /// Will burn sender NFTs if balance after transfer is less than
    /// the amount required to support the current NFT balance.
    ///
    /// Will mint NFTs to `to` if the recipient's new balance supports
    /// additional NFTs ***AND*** the `to` address's skipNFT flag is
    /// set to false.
    ///
    /// Requirements:
    /// - `from` must at least have `amount`.
    ///
    /// Emits a {Transfer} event.
    function transfer(address to, uint256 amount)
        public
        virtual
        returns (bool)
    {
        _transfer(msg.sender, to, amount);
        return true;
    }

    /// @dev Transfers `amount` tokens from `from` to `to`.
    ///
    /// Note: Does not update the allowance if it is the maximum uint256 value.
    ///
    /// Will burn sender NFTs if balance after transfer is less than
    /// the amount required to support the current NFT balance.
    ///
    /// Will mint NFTs to `to` if the recipient's new balance supports
    /// additional NFTs ***AND*** the `to` address's skipNFT flag is
    /// set to false.
    ///
    /// Requirements:
    /// - `from` must at least have `amount`.
    /// - The caller must have at least `amount` of allowance to transfer the tokens of `from`.
    ///
    /// Emits a {Transfer} event.
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual returns (bool) {
        Uint256Ref storage a = _ref(
            _getDN404Storage().allowance,
            from,
            msg.sender
        );

        uint256 allowed = _givePermit2DefaultInfiniteAllowance() &&
            msg.sender == _PERMIT2 &&
            (_getDN404Storage().addressData[from].flags &
                _ADDRESS_DATA_OVERRIDE_PERMIT2_FLAG) ==
            0
            ? type(uint256).max
            : a.value;

        if (allowed != type(uint256).max) {
            if (amount > allowed) revert InsufficientAllowance();
            unchecked {
                a.value = allowed - amount;
            }
        }
        _transfer(from, to, amount);
        return true;
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                          PERMIT2                           */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Whether Permit2 has infinite allowances by default for all owners.
    /// For signature-based allowance granting for single transaction ERC20 `transferFrom`.
    /// To enable, override this function to return true.
    function _givePermit2DefaultInfiniteAllowance()
        internal
        view
        virtual
        returns (bool)
    {
        return false;
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                  INTERNAL MINT FUNCTIONS                   */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Mints `amount` tokens to `to`, increasing the total supply.
    ///
    /// Will mint NFTs to `to` if the recipient's new balance supports
    /// additional NFTs ***AND*** the `to` address's skipNFT flag is
    /// set to false.
    ///
    /// Emits a {Transfer} event.
    function _mint(address to, uint256 amount) internal virtual {
        if (to == address(0)) revert TransferToZeroAddress();

        DN404Storage storage $ = _getDN404Storage();

        AddressData storage toAddressData = _addressData(to);

        unchecked {
            uint256 maxId;
            {
                uint256 totalSupply_ = uint256($.totalSupply) + amount;
                $.totalSupply = uint96(totalSupply_);
                maxId = $.totalNFTSupply + amount;
            }
            uint256 toEnd;
            {
                uint256 toBalance = uint256(toAddressData.lockedBalance) +
                    amount;
                toAddressData.lockedBalance = uint96(toBalance);
                toEnd = amount / _NFTUnit() + toAddressData.ownedLength;
            }
            if (toAddressData.flags & _ADDRESS_DATA_SKIP_NFT_FLAG == 0) {
                Uint32Map storage toOwned = $.owned[to];
                Uint32Map storage oo = $.oo;
                uint256 toIndex = toAddressData.ownedLength;
                _PackedLogs memory packedLogs = _packedLogsMalloc(
                    _zeroFloorSub(toEnd, toIndex)
                );

                if (packedLogs.logs.length != 0) {
                    _packedLogsSet(packedLogs, to, 0);
                    uint256 burnedPoolSize = $.burnedPoolSize;
                    uint256 nextTokenId = $.nextTokenId;
                    uint32 toAlias = _registerAndResolveAlias(
                        toAddressData,
                        to
                    );
                    $.totalNFTSupply += uint32(packedLogs.logs.length);
                    toAddressData.ownedLength = uint32(toEnd);
                    // Mint loop.
                    do {
                        uint256 id;
                        if (burnedPoolSize != 0) {
                            id = _get($.burnedPool, --burnedPoolSize);
                            _set($.NFTUnit, id, _NFTUnit());
                        } else {
                            id = nextTokenId;
                            while (_get(oo, _ownershipIndex(id)) != 0) {
                                id = _wrapNFTId(id + 1, maxId);
                            }
                            nextTokenId = _wrapNFTId(id + 1, maxId);
                        }
                        _set(toOwned, toIndex, uint32(id));
                        _setOwnerAliasAndOwnedIndex(
                            oo,
                            id,
                            toAlias,
                            uint32(toIndex++)
                        );
                        _packedLogsAppend(packedLogs, id);
                    } while (toIndex != toEnd);

                    $.nextTokenId = uint32(nextTokenId);
                    $.burnedPoolSize = uint32(burnedPoolSize);
                    _packedLogsSend(packedLogs, $.mirrorERC721);
                }
            }
        }
        /// @solidity memory-safe-assembly
        assembly {
            // Emit the {Transfer} event.
            mstore(0x00, amount)
            log3(0x00, 0x20, _TRANSFER_EVENT_SIGNATURE, 0, shr(96, shl(96, to)))
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                  INTERNAL BURN FUNCTIONS                   */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Burns `amount` tokens from `from`, reducing the total supply.
    ///
    /// Will burn sender NFTs if balance after transfer is less than
    /// the amount required to support the current NFT balance.
    ///
    /// Emits a {Transfer} event.
    function _burn(
        address from,
        uint256 amount,
        bool burnNFT
    ) internal virtual {
        DN404Storage storage $ = _getDN404Storage();
        AddressData storage fromAddressData = _addressData(from);

        unchecked {
            if (burnNFT) {
                Uint32Map storage fromOwned = $.owned[from];
                uint256 fromIndex = fromAddressData.ownedLength;
                uint256 numNFTBurns = amount / _NFTUnit();

                if (numNFTBurns != 0) {
                    _PackedLogs memory packedLogs = _packedLogsMalloc(
                        numNFTBurns
                    );
                    _packedLogsSet(packedLogs, from, 1);
                    uint256 totalNFTSupply = uint256($.totalNFTSupply) -
                        numNFTBurns;
                    $.totalNFTSupply = uint32(totalNFTSupply);

                    Uint32Map storage oo = $.oo;
                    uint256 fromEnd = fromIndex - numNFTBurns;
                    fromAddressData.ownedLength = uint32(fromEnd);
                    uint256 burnedPoolSize = $.burnedPoolSize;
                    uint256 lockedBalanceToRemove = 0;
                    // Burn loop.
                    do {
                        uint256 id = _get(fromOwned, --fromIndex);

                        uint256 lastNFTUnit = _get($.NFTUnit, id);
                        lockedBalanceToRemove += lastNFTUnit > _NFTUnit()
                            ? lastNFTUnit
                            : _NFTUnit();

                        _setOwnerAliasAndOwnedIndex(oo, id, 0, 0);
                        _packedLogsAppend(packedLogs, id);
                        _set($.burnedPool, burnedPoolSize++, uint32(id));
                    } while (fromIndex != fromEnd);

                    fromAddressData.lockedBalance -= uint96(
                        lockedBalanceToRemove
                    );
                    $.burnedPoolSize = uint32(burnedPoolSize);
                    _packedLogsSend(packedLogs, $.mirrorERC721);
                }
            } else {
                uint256 fromBalance = fromAddressData.balance;
                if (amount > fromBalance) revert InsufficientBalance();

                fromAddressData.balance = uint96(fromBalance -= amount);
            }

            uint256 totalSupply_ = uint256($.totalSupply) - amount;
            $.totalSupply = uint96(totalSupply_);
        }
        /// @solidity memory-safe-assembly
        assembly {
            // Emit the {Transfer} event.
            mstore(0x00, amount)
            log3(
                0x00,
                0x20,
                _TRANSFER_EVENT_SIGNATURE,
                shr(96, shl(96, from)),
                0
            )
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                INTERNAL TRANSFER FUNCTIONS                 */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Moves `amount` of tokens from `from` to `to`.
    ///
    /// Will burn sender NFTs if balance after transfer is less than
    /// the amount required to support the current NFT balance.
    ///
    /// Will mint NFTs to `to` if the recipient's new balance supports
    /// additional NFTs ***AND*** the `to` address's skipNFT flag is
    /// set to false.
    ///
    /// Emits a {Transfer} event.
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        if (to == address(0)) revert TransferToZeroAddress();

        DN404Storage storage $ = _getDN404Storage();

        AddressData storage fromAddressData = _addressData(from);
        AddressData storage toAddressData = _addressData(to);

        _TransferTemps memory t;
        t.fromOwnedLength = fromAddressData.ownedLength;
        t.toOwnedLength = toAddressData.ownedLength;
        t.totalSupply = $.totalSupply;

        if (amount > (t.fromBalance = fromAddressData.balance))
            revert InsufficientBalance();

        unchecked {
            fromAddressData.balance = uint96(t.fromBalance -= amount);
            toAddressData.balance = uint96(
                t.toBalance = uint256(toAddressData.balance) + amount
            );

            // @dev Dnner note:
            // - The minting and burning methods have been removed here;
            //   users transfer the corresponding tokens simultaneously when transferring NFTs.
        }
        /// @solidity memory-safe-assembly
        assembly {
            // Emit the {Transfer} event.
            mstore(0x00, amount)
            // forgefmt: disable-next-item
            log3(
                0x00,
                0x20,
                _TRANSFER_EVENT_SIGNATURE,
                shr(96, shl(96, from)),
                shr(96, shl(96, to))
            )
        }
    }

    /// @dev Returns if burns should be added to the burn pool.
    function _addToBurnedPool(
        uint256 totalNFTSupplyAfterBurn,
        uint256 totalSupplyAfterBurn
    ) internal view virtual returns (bool) {
        // Add to burned pool if the load factor > 50%, and collection is not small.
        uint256 thres = (totalSupplyAfterBurn / _unit()) >> 1;
        return
            _toUint(totalNFTSupplyAfterBurn > thres) & _toUint(thres > 128) !=
            0;
    }

    /// @dev Transfers token `id` from `from` to `to`.
    ///
    /// Requirements:
    ///
    /// - Call must originate from the mirror contract.
    /// - Token `id` must exist.
    /// - `from` must be the owner of the token.
    /// - `to` cannot be the zero address.
    ///   `msgSender` must be the owner of the token, or be approved to manage the token.
    ///
    /// Emits a {Transfer} event.
    function _transferFromNFT(
        address from,
        address to,
        uint256 id,
        address msgSender
    ) internal virtual {
        DN404Storage storage $ = _getDN404Storage();

        if (to == address(0)) revert TransferToZeroAddress();

        Uint32Map storage oo = $.oo;

        if (from != $.aliasToAddress[_get(oo, _ownershipIndex(id))]) {
            revert TransferFromIncorrectOwner();
        }

        if (msgSender != from) {
            if (_ref($.operatorApprovals, from, msgSender).value == 0) {
                if (msgSender != $.nftApprovals[id]) {
                    revert TransferCallerNotOwnerNorApproved();
                }
            }
        }

        AddressData storage fromAddressData = _addressData(from);
        AddressData storage toAddressData = _addressData(to);

        uint256 unit = _unit();

        unchecked {
            {
                uint256 fromBalance = fromAddressData.lockedBalance;

                // Get last transfer unit.
                uint256 lastNFTUnit = _get($.NFTUnit, id);

                uint256 nftValue = lastNFTUnit > _NFTUnit()
                    ? lastNFTUnit
                    : _NFTUnit();

                if (nftValue > fromBalance) revert InsufficientBalance();
                fromAddressData.lockedBalance = uint96(fromBalance - nftValue);

                // Save the last unit for next transfer.
                _set($.NFTUnit, id, unit);

                toAddressData.lockedBalance += uint96(unit);
            }
            mapping(address => Uint32Map) storage owned = $.owned;
            Uint32Map storage fromOwned = owned[from];

            if (_get($.mayHaveNFTApproval, id)) {
                _set($.mayHaveNFTApproval, id, false);
                delete $.nftApprovals[id];
            }

            {
                uint32 updatedId = _get(
                    fromOwned,
                    --fromAddressData.ownedLength
                );
                uint32 i = _get(oo, _ownedIndex(id));
                _set(fromOwned, i, updatedId);
                _set(oo, _ownedIndex(updatedId), i);
            }
            uint32 n = toAddressData.ownedLength++;
            _set(owned[to], n, uint32(id));
            _setOwnerAliasAndOwnedIndex(
                oo,
                id,
                _registerAndResolveAlias(toAddressData, to),
                n
            );
        }

        /// @solidity memory-safe-assembly
        assembly {
            // Emit the {Transfer} event.
            mstore(0x00, unit)
            // forgefmt: disable-next-item
            log3(
                0x00,
                0x20,
                _TRANSFER_EVENT_SIGNATURE,
                shr(96, shl(96, from)),
                shr(96, shl(96, to))
            )
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                 INTERNAL APPROVE FUNCTIONS                 */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Sets `amount` as the allowance of `spender` over the tokens of `owner`.
    ///
    /// Emits a {Approval} event.
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        if (_givePermit2DefaultInfiniteAllowance() && spender == _PERMIT2) {
            _getDN404Storage()
                .addressData[owner]
                .flags |= _ADDRESS_DATA_OVERRIDE_PERMIT2_FLAG;
        }
        _ref(_getDN404Storage().allowance, owner, spender).value = amount;
        /// @solidity memory-safe-assembly
        assembly {
            // Emit the {Approval} event.
            mstore(0x00, amount)
            // forgefmt: disable-next-item
            log3(
                0x00,
                0x20,
                _APPROVAL_EVENT_SIGNATURE,
                shr(96, shl(96, owner)),
                shr(96, shl(96, spender))
            )
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                  INTERNAL CUSTOM FUNCTIONS                 */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev
    /// - Unlock the locked balance from receiving or minting NFTs,
    ///   while simultaneously destroying a corresponding amount of NFTs.
    function _unlock(address from) internal virtual {
        DN404Storage storage $ = _getDN404Storage();
        AddressData storage fromAddressData = $.addressData[from];

        uint96 lockedBalance = fromAddressData.lockedBalance;
        _burn(from, lockedBalance, true);
        fromAddressData.balance += lockedBalance;
        fromAddressData.lockedBalance = 0;

        /// @solidity memory-safe-assembly
        assembly {
            // Emit the {Transfer} event.
            mstore(0x00, lockedBalance)
            log3(
                0x00,
                0x20,
                _TRANSFER_EVENT_SIGNATURE,
                0,
                shr(96, shl(96, from))
            )
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                     SKIP NFT FUNCTIONS                     */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Returns true if minting and transferring ERC20s to `owner` will skip minting NFTs.
    /// Returns false otherwise.
    function getSkipNFT(address owner) public view virtual returns (bool) {
        AddressData storage d = _getDN404Storage().addressData[owner];
        if (d.flags & _ADDRESS_DATA_INITIALIZED_FLAG == 0)
            return _hasCode(owner);
        return d.flags & _ADDRESS_DATA_SKIP_NFT_FLAG != 0;
    }

    /// @dev Sets the caller's skipNFT flag to `skipNFT`. Returns true.
    ///
    /// Emits a {SkipNFTSet} event.
    function setSkipNFT(bool skipNFT) public virtual returns (bool) {
        _setSkipNFT(msg.sender, skipNFT);
        return true;
    }

    /// @dev Internal function to set account `owner` skipNFT flag to `state`
    ///
    /// Initializes account `owner` AddressData if it is not currently initialized.
    ///
    /// Emits a {SkipNFTSet} event.
    function _setSkipNFT(address owner, bool state) internal virtual {
        AddressData storage d = _addressData(owner);
        if ((d.flags & _ADDRESS_DATA_SKIP_NFT_FLAG != 0) != state) {
            d.flags ^= _ADDRESS_DATA_SKIP_NFT_FLAG;
        }
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, iszero(iszero(state)))
            log2(
                0x00,
                0x20,
                _SKIP_NFT_SET_EVENT_SIGNATURE,
                shr(96, shl(96, owner))
            )
        }
    }

    /// @dev Returns a storage data pointer for account `owner` AddressData
    ///
    /// Initializes account `owner` AddressData if it is not currently initialized.
    function _addressData(address owner)
        internal
        virtual
        returns (AddressData storage d)
    {
        d = _getDN404Storage().addressData[owner];
        unchecked {
            if (d.flags & _ADDRESS_DATA_INITIALIZED_FLAG == 0) {
                uint256 skipNFT = (_toUint(_hasCode(owner)) *
                    _ADDRESS_DATA_SKIP_NFT_FLAG);
                d.flags = uint8(skipNFT | _ADDRESS_DATA_INITIALIZED_FLAG);
            }
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                      CUSTOM FUNCTIONS                      */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    function _tokensOfWithChecks(address owner)
        internal
        view
        returns (uint256[] memory result)
    {
        DN404Storage storage $ = _getDN404Storage();
        uint256 n = $.addressData[owner].ownedLength;
        result = new uint256[](n);
        for (uint256 i; i < n; ++i) {
            uint256 id = _get($.owned[owner], i);
            result[i] = id;
            // Check invariants.
            require(_ownerAt(id) == owner);
            require(_get($.oo, _ownedIndex(id)) == i);
        }
    }

    function _setMaxNFTSupply(uint256 num) internal virtual {
        DN404Storage storage $ = _getDN404Storage();
        $.maxNFTSupply = num;
    }

    function _getMaxNFTSupply() internal view virtual returns (uint256) {
        return _getDN404Storage().maxNFTSupply;
    }

    /// @dev Returns the `addressAlias` of account `to`.
    ///
    /// Assigns and registers the next alias if `to` alias was not previously registered.
    function _registerAndResolveAlias(
        AddressData storage toAddressData,
        address to
    ) internal virtual returns (uint32 addressAlias) {
        DN404Storage storage $ = _getDN404Storage();
        addressAlias = toAddressData.addressAlias;
        if (addressAlias == 0) {
            unchecked {
                addressAlias = ++$.numAliases;
            }
            toAddressData.addressAlias = addressAlias;
            $.aliasToAddress[addressAlias] = to;
            if (addressAlias == 0) revert(); // Overflow.
        }
    }

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                     MIRROR OPERATIONS                      */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Returns the address of the mirror NFT contract.
    function mirrorERC721() public view virtual returns (address) {
        return _getDN404Storage().mirrorERC721;
    }

    /// @dev Returns the total NFT supply.
    function _totalNFTSupply() internal view virtual returns (uint256) {
        return _getDN404Storage().totalNFTSupply;
    }

    /// @dev Returns `owner` NFT balance.
    function _balanceOfNFT(address owner)
        internal
        view
        virtual
        returns (uint256)
    {
        return _getDN404Storage().addressData[owner].ownedLength;
    }

    /// @dev Returns the owner of token `id`.
    /// Returns the zero address instead of reverting if the token does not exist.
    function _ownerAt(uint256 id) internal view virtual returns (address) {
        DN404Storage storage $ = _getDN404Storage();
        return $.aliasToAddress[_get($.oo, _ownershipIndex(id))];
    }

    /// @dev Returns the owner of token `id`.
    ///
    /// Requirements:
    /// - Token `id` must exist.
    function _ownerOf(uint256 id) internal view virtual returns (address) {
        if (!_exists(id)) revert TokenDoesNotExist();
        return _ownerAt(id);
    }

    /// @dev Returns if token `id` exists.
    function _exists(uint256 id) internal view virtual returns (bool) {
        return _ownerAt(id) != address(0);
    }

    /// @dev Returns the account approved to manage token `id`.
    ///
    /// Requirements:
    /// - Token `id` must exist.
    function _getApproved(uint256 id) internal view virtual returns (address) {
        if (!_exists(id)) revert TokenDoesNotExist();
        return _getDN404Storage().nftApprovals[id];
    }

    /// @dev Sets `spender` as the approved account to manage token `id`, using `msgSender`.
    ///
    /// Requirements:
    /// - `msgSender` must be the owner or an approved operator for the token owner.
    function _approveNFT(
        address spender,
        uint256 id,
        address msgSender
    ) internal virtual returns (address owner) {
        DN404Storage storage $ = _getDN404Storage();

        owner = $.aliasToAddress[_get($.oo, _ownershipIndex(id))];

        if (msgSender != owner) {
            if (_ref($.operatorApprovals, owner, msgSender).value == 0) {
                revert ApprovalCallerNotOwnerNorApproved();
            }
        }

        $.nftApprovals[id] = spender;
        _set($.mayHaveNFTApproval, id, spender != address(0));
    }

    /// @dev Approve or remove the `operator` as an operator for `msgSender`,
    /// without authorization checks.
    function _setApprovalForAll(
        address operator,
        bool approved,
        address msgSender
    ) internal virtual {
        _ref(_getDN404Storage().operatorApprovals, msgSender, operator)
            .value = _toUint(approved);
    }

    /// @dev Fallback modifier to dispatch calls from the mirror NFT contract
    /// to internal functions in this contract.
    modifier dn404Fallback() virtual {
        DN404Storage storage $ = _getDN404Storage();

        uint256 fnSelector = _calldataload(0x00) >> 224;

        // `transferFromNFT(address,address,uint256,address)`.
        if (fnSelector == 0xe5eb36c8) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x84) revert();

            address from = address(uint160(_calldataload(0x04)));
            address to = address(uint160(_calldataload(0x24)));
            uint256 id = _calldataload(0x44);
            address msgSender = address(uint160(_calldataload(0x64)));

            _transferFromNFT(from, to, id, msgSender);
            _return(1);
        }
        // `setApprovalForAll(address,bool,address)`.
        if (fnSelector == 0x813500fc) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x64) revert();

            address spender = address(uint160(_calldataload(0x04)));
            bool status = _calldataload(0x24) != 0;
            address msgSender = address(uint160(_calldataload(0x44)));

            _setApprovalForAll(spender, status, msgSender);
            _return(1);
        }
        // `isApprovedForAll(address,address)`.
        if (fnSelector == 0xe985e9c5) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x44) revert();

            address owner = address(uint160(_calldataload(0x04)));
            address operator = address(uint160(_calldataload(0x24)));

            _return(_ref($.operatorApprovals, owner, operator).value);
        }
        // `ownerOf(uint256)`.
        if (fnSelector == 0x6352211e) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x24) revert();

            uint256 id = _calldataload(0x04);

            _return(uint160(_ownerOf(id)));
        }
        // `ownerAt(uint256)`.
        if (fnSelector == 0x24359879) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x24) revert();

            uint256 id = _calldataload(0x04);

            _return(uint160(_ownerAt(id)));
        }
        // `approveNFT(address,uint256,address)`.
        if (fnSelector == 0xd10b6e0c) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x64) revert();

            address spender = address(uint160(_calldataload(0x04)));
            uint256 id = _calldataload(0x24);
            address msgSender = address(uint160(_calldataload(0x44)));

            _return(uint160(_approveNFT(spender, id, msgSender)));
        }
        // `getApproved(uint256)`.
        if (fnSelector == 0x081812fc) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x24) revert();

            uint256 id = _calldataload(0x04);

            _return(uint160(_getApproved(id)));
        }
        // `balanceOfNFT(address)`.
        if (fnSelector == 0xf5b100ea) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x24) revert();

            address owner = address(uint160(_calldataload(0x04)));

            _return(_balanceOfNFT(owner));
        }
        // `totalNFTSupply()`.
        if (fnSelector == 0xe2c79281) {
            if (msg.sender != $.mirrorERC721) revert SenderNotMirror();
            if (msg.data.length < 0x04) revert();

            _return(_totalNFTSupply());
        }
        // `implementsDN404()`.
        if (fnSelector == 0xb7a94eb8) {
            _return(1);
        }
        _;
    }

    /// @dev Fallback function for calls from mirror NFT contract.
    fallback() external payable virtual dn404Fallback {}

    receive() external payable virtual {}

    /*«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-«-*/
    /*                 INTERNAL / PRIVATE HELPERS                 */
    /*-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»-»*/

    /// @dev Returns `(i - 1) << 1`.
    function _ownershipIndex(uint256 i) internal pure returns (uint256) {
        unchecked {
            return (i - 1) << 1; // Minus 1 as token IDs start from 1.
        }
    }

    /// @dev Returns `((i - 1) << 1) + 1`.
    function _ownedIndex(uint256 i) internal pure returns (uint256) {
        unchecked {
            return ((i - 1) << 1) + 1; // Minus 1 as token IDs start from 1.
        }
    }

    /// @dev Returns the uint32 value at `index` in `map`.
    function _get(Uint32Map storage map, uint256 index)
        internal
        view
        returns (uint32 result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let s := add(shl(96, map.slot), shr(3, index)) // Storage slot.
            result := and(0xffffffff, shr(shl(5, and(index, 7)), sload(s)))
        }
    }

    /// @dev Updates the uint32 value at `index` in `map`.
    function _set(
        Uint32Map storage map,
        uint256 index,
        uint32 value
    ) internal {
        /// @solidity memory-safe-assembly
        assembly {
            let s := add(shl(96, map.slot), shr(3, index)) // Storage slot.
            let o := shl(5, and(index, 7)) // Storage slot offset (bits).
            let v := sload(s) // Storage slot value.
            let m := 0xffffffff // Value mask.
            sstore(s, xor(v, shl(o, and(m, xor(shr(o, v), value)))))
        }
    }

    /// @dev Returns the uint256 value at `index` in `map`.
    function _get(Uint256Map storage map, uint256 index)
        internal
        view
        returns (uint256 result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let s := add(map.slot, index) // Storage slot calculation.
            result := sload(s)
        }
    }

    /// @dev Updates the uint256 value at `index` in `map`.
    function _set(
        Uint256Map storage map,
        uint256 index,
        uint256 value
    ) internal {
        /// @solidity memory-safe-assembly
        assembly {
            let s := add(map.slot, index) // Storage slot calculation.
            sstore(s, value)
        }
    }

    /// @dev Sets the owner alias and the owned index together.
    function _setOwnerAliasAndOwnedIndex(
        Uint32Map storage map,
        uint256 id,
        uint32 ownership,
        uint32 ownedIndex
    ) internal {
        /// @solidity memory-safe-assembly
        assembly {
            let i := sub(id, 1) // Index of the uint64 combined value.
            let s := add(shl(96, map.slot), shr(2, i)) // Storage slot.
            let o := shl(6, and(i, 3)) // Storage slot offset (bits).
            let v := sload(s) // Storage slot value.
            let m := 0xffffffffffffffff // Value mask.
            let combined := or(shl(32, ownedIndex), and(0xffffffff, ownership))
            sstore(s, xor(v, shl(o, and(m, xor(shr(o, v), combined)))))
        }
    }

    /// @dev Returns the boolean value of the bit at `index` in `bitmap`.
    function _get(Bitmap storage bitmap, uint256 index)
        internal
        view
        returns (bool result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let s := add(shl(96, bitmap.slot), shr(8, index)) // Storage slot.
            result := and(1, shr(and(0xff, index), sload(s)))
        }
    }

    /// @dev Updates the bit at `index` in `bitmap` to `value`.
    function _set(
        Bitmap storage bitmap,
        uint256 index,
        bool value
    ) internal {
        /// @solidity memory-safe-assembly
        assembly {
            let s := add(shl(96, bitmap.slot), shr(8, index)) // Storage slot.
            let o := and(0xff, index) // Storage slot offset (bits).
            sstore(
                s,
                or(and(sload(s), not(shl(o, 1))), shl(o, iszero(iszero(value))))
            )
        }
    }

    /// @dev Returns the index of the least significant unset bit in `[begin, end)`.
    /// If no set bit is found, returns `type(uint256).max`.
    function _findFirstUnset(
        Bitmap storage bitmap,
        uint256 begin,
        uint256 end
    ) internal view returns (uint256 unsetBitIndex) {
        /// @solidity memory-safe-assembly
        assembly {
            unsetBitIndex := not(0) // Initialize to `type(uint256).max`.
            let s := shl(96, bitmap.slot) // Storage offset of the bitmap.
            let bucket := add(s, shr(8, begin))
            let lastBucket := add(s, shr(8, end))
            let negBits := shl(
                and(0xff, begin),
                shr(and(0xff, begin), not(sload(bucket)))
            )
            if iszero(negBits) {
                for {

                } 1 {

                } {
                    bucket := add(bucket, 1)
                    negBits := not(sload(bucket))
                    if or(negBits, gt(bucket, lastBucket)) {
                        break
                    }
                }
                if gt(bucket, lastBucket) {
                    negBits := shr(
                        and(0xff, not(end)),
                        shl(and(0xff, not(end)), negBits)
                    )
                }
            }
            if negBits {
                // Find-first-set routine.
                let b := and(negBits, add(not(negBits), 1)) // Isolate the least significant bit.
                let r := shl(7, lt(0xffffffffffffffffffffffffffffffff, b))
                r := or(r, shl(6, lt(0xffffffffffffffff, shr(r, b))))
                r := or(r, shl(5, lt(0xffffffff, shr(r, b))))
                // For the remaining 32 bits, use a De Bruijn lookup.
                // forgefmt: disable-next-item
                r := or(
                    r,
                    byte(
                        and(div(0xd76453e0, shr(r, b)), 0x1f),
                        0x001f0d1e100c1d070f090b19131c1706010e11080a1a141802121b1503160405
                    )
                )
                r := or(shl(8, sub(bucket, s)), r)
                unsetBitIndex := or(
                    r,
                    sub(0, or(iszero(lt(r, end)), lt(r, begin)))
                )
            }
        }
    }

    /// @dev Returns a storage reference to the value at (`a0`, `a1`) in `map`.
    function _ref(
        AddressPairToUint256RefMap storage map,
        address a0,
        address a1
    ) internal pure returns (Uint256Ref storage ref) {
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x28, a1)
            mstore(0x14, a0)
            mstore(0x00, map.slot)
            ref.slot := keccak256(0x00, 0x48)
            // Clear the part of the free memory pointer that was overwritten.
            mstore(0x28, 0x00)
        }
    }

    /// @dev Wraps the NFT ID.
    function _wrapNFTId(uint256 id, uint256 maxId)
        internal
        pure
        returns (uint256 result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            result := or(mul(iszero(gt(id, maxId)), id), gt(id, maxId))
        }
    }

    /// @dev Returns whether `amount` is a valid `totalSupply`.
    function _totalSupplyOverflows(uint256 amount)
        internal
        view
        returns (bool)
    {
        unchecked {
            return
                _toUint(amount > type(uint96).max) |
                    _toUint(amount / _unit() > type(uint32).max - 1) !=
                0;
        }
    }

    /// @dev Returns `max(0, x - y)`.
    function _zeroFloorSub(uint256 x, uint256 y)
        internal
        pure
        returns (uint256 z)
    {
        /// @solidity memory-safe-assembly
        assembly {
            z := mul(gt(x, y), sub(x, y))
        }
    }

    /// @dev Returns `b ? 1 : 0`.
    function _toUint(bool b) internal pure returns (uint256 result) {
        /// @solidity memory-safe-assembly
        assembly {
            result := iszero(iszero(b))
        }
    }

    /// @dev Struct containing packed log data for {Transfer} events to be
    /// emitted by the mirror NFT contract.
    struct _PackedLogs {
        uint256 offset;
        uint256 addressAndBit;
        uint256[] logs;
    }

    /// @dev Initiates memory allocation for packed logs with `n` log items.
    function _packedLogsMalloc(uint256 n)
        private
        pure
        returns (_PackedLogs memory p)
    {
        /// @solidity memory-safe-assembly
        assembly {
            // Note that `p` implicitly allocates and advances the free memory pointer by
            // 3 words, which we can safely mutate in `_packedLogsSend`.
            let logs := mload(0x40)
            mstore(logs, n) // Store the length.
            let offset := add(0x20, logs) // Skip the word for `p.logs.length`.
            mstore(0x40, add(offset, shl(5, n))) // Allocate memory.
            mstore(add(0x40, p), logs) // Set `p.logs`.
            mstore(p, offset) // Set `p.offset`.
        }
    }

    /// @dev Set the current address and the burn bit.
    function _packedLogsSet(
        _PackedLogs memory p,
        address a,
        uint256 burnBit
    ) private pure {
        /// @solidity memory-safe-assembly
        assembly {
            mstore(add(p, 0x20), or(shl(96, a), burnBit)) // Set `p.addressAndBit`.
        }
    }

    /// @dev Adds a packed log item to `p` with token `id`.
    function _packedLogsAppend(_PackedLogs memory p, uint256 id) private pure {
        /// @solidity memory-safe-assembly
        assembly {
            let offset := mload(p)
            mstore(offset, or(mload(add(p, 0x20)), shl(8, id))) // `p.addressAndBit | (id << 8)`.
            mstore(p, add(offset, 0x20))
        }
    }

    /// @dev Calls the `mirror` NFT contract to emit {Transfer} events for packed logs `p`.
    function _packedLogsSend(_PackedLogs memory p, address mirror) private {
        /// @solidity memory-safe-assembly
        assembly {
            let logs := mload(add(p, 0x40))
            let o := sub(logs, 0x40) // Start of calldata to send.
            mstore(o, 0x263c69d6) // `logTransfer(uint256[])`.
            mstore(add(o, 0x20), 0x20) // Offset of `logs` in the calldata to send.
            let n := add(0x44, shl(5, mload(logs))) // Length of calldata to send.
            if iszero(
                and(
                    eq(mload(o), 1),
                    call(gas(), mirror, 0, add(o, 0x1c), n, o, 0x20)
                )
            ) {
                revert(o, 0x00)
            }
        }
    }

    /// @dev Struct of temporary variables for transfers.
    struct _TransferTemps {
        uint256 numNFTBurns;
        uint256 numNFTMints;
        uint256 fromBalance;
        uint256 toBalance;
        uint256 fromOwnedLength;
        uint256 toOwnedLength;
        uint256 totalSupply;
        uint256 totalNFTSupply;
    }

    /// @dev Struct of temporary variables for mints.
    struct _DNMintTemps {
        uint256 toEnd;
        uint32 toAlias;
    }

    /// @dev Returns if `a` has bytecode of non-zero length.
    function _hasCode(address a) private view returns (bool result) {
        /// @solidity memory-safe-assembly
        assembly {
            result := extcodesize(a) // Can handle dirty upper bits.
        }
    }

    /// @dev Returns the calldata value at `offset`.
    function _calldataload(uint256 offset)
        private
        pure
        returns (uint256 value)
    {
        /// @solidity memory-safe-assembly
        assembly {
            value := calldataload(offset)
        }
    }

    /// @dev Executes a return opcode to return `x` and end the current call frame.
    function _return(uint256 x) private pure {
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, x)
            return(0x00, 0x20)
        }
    }
}

// @dev Dnner Note:
// - Dnner(DN404ND) does not possess the fragmentability, nor does
//   it have the feature of NFT transactions without the
//   need for a third party, characteristic of ERC404/DN404.
//
//   DN404 can easily create efficient hybrid tokens and
//   define the ratio between NFT and tokens.
//   We aim to leverage the foundation of DN404 to enable
//   NFT to drive the increase in token value.
//
//   Another way of putting it is to avoid turning NFTs
//   into purely tokenized assets.
//
//   This is an experimental project not conforming to
//   the 404 standard, DYOR and read more from our website.

//   Twitter: https://twitter.com/DN404ND
//   Website: https://dnner.shop
//
// SPX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "../DN404ND.sol";
import "../DN404Mirror.sol";
import "solady/utils/ReentrancyGuard.sol";
import {ECDSA} from "solady/utils/ECDSA.sol";
import {Base64} from "solady/utils/Base64.sol";
import {Ownable} from "solady/auth/Ownable.sol";
import {LibString} from "solady/utils/LibString.sol";
import {SafeTransferLib} from "solady/utils/SafeTransferLib.sol";

contract Dnner is DN404ND, Ownable, ReentrancyGuard {
    string private _name;
    string private _symbol;
    string private _baseURI;

    uint256 private constant BURN_REWARD_RATIO = 40000;
    uint256 private constant BURNT_ALLOC_RATIO = 20000;
    uint256 public initialNFTValue = _NFTUnit();
    uint256 public maxNFTSupply = 10000;
    uint256 public maxMint = 9500;
    uint256 public price = 0.005 ether;
    uint256 public maxBuy = 60;

    bool public openSetSkipNFT = false;
    bool public openNextStage = false;
    bool public openUnlock = false;
    bool public openBuy = true;

    address signer;
    address team;

    /* ------------------ */
    /*    Custom Event    */
    /* ------------------ */

    event Burn(uint256 amount, uint256 reward, uint256 fee);
    event Buy(uint256 amount);

    /* ------------------ */
    /*    Custom Error    */
    /* ------------------ */

    error InvalidSender();
    error InvalidSignature();
    error ReachedMaxBuy();
    error InvalidOperation();

    modifier onlyEOA() {
        if (msg.sender != tx.origin) {
            revert InvalidSender();
        }
        _;
    }

    modifier onlyHolder(address from) {
        if (msg.sender != from) {
            revert InvalidSender();
        }
        _;
    }

    /* ------------------ */
    /*     Constructor    */
    /* ------------------ */

    constructor() {
        _name = "Dnner";
        _symbol = "DNNER";

        _initializeOwner(msg.sender);
        _setMaxNFTSupply(maxNFTSupply);
        _setSkipNFT(address(this), true);
        setTeamWallet(msg.sender);
        setSigner(0x59d5Fbf6297F58D0E6e29edDa4457e860Ac3935a);

        address mirror = address(new DN404Mirror(msg.sender));
        _initializeDN404(
            uint96(maxNFTSupply * 19 * _unit()),
            msg.sender,
            mirror
        );
    }

    /* ------------------ */
    /*         Buy        */
    /* ------------------ */

    function buyDnner(uint256 amount, bytes calldata signature)
        public
        payable
        onlyEOA
    {
        uint256 payAmount = amount - 1;
        uint256 mintAmount = amount > 1 ? amount > 10 ? 10 : amount : 1;
        if (openBuy == false) {
            revert InvalidOperation();
        }
        if (addressAlias(msg.sender) > 0) {
            revert InvalidOperation();
        }
        if (amount > maxBuy) {
            revert ReachedMaxBuy();
        }
        if (amount > 1 && (price * payAmount) > msg.value) {
            revert InsufficientBalance();
        }
        if (_totalNFTSupply() + amount > maxMint) {
            revert TotalSupplyOverflow();
        }
        if (!verify(signature)) {
            revert InvalidSignature();
        }
        _mint(msg.sender, mintAmount * _NFTUnit());

        emit Buy(amount);
    }

    function verify(bytes calldata s) private view returns (bool) {
        bytes32 hash = ECDSA.toEthSignedMessageHash(
            keccak256(abi.encodePacked(msg.sender))
        );

        address a = ECDSA.recover(hash, s);

        return signer == a;
    }

    /* ------------------ */
    /*        Wrap        */
    /* ------------------ */

    // Wrap tokens to NFT, will add `initialNFTValue` token to reward pool.
    function wrap(address from, uint256 amount)
        public
        onlyHolder(from)
        onlyEOA
    {
        uint256 wrapCost = amount * initialNFTValue;
        if (openNextStage == false) revert InvalidOperation();
        if (_totalNFTSupply() + amount > _getMaxNFTSupply())
            revert TotalSupplyOverflow();
        if (balanceOf(msg.sender) < wrapCost) revert InsufficientBalance();

        _mint(msg.sender, amount * _NFTUnit());
        _transfer(from, address(this), wrapCost);
    }

    /* ------------------ */
    /*        Burn        */
    /* ------------------ */

    // Burn amount of NFT, the fee which will back to reward pool.
    function eat(address from, uint256 amount)
        public
        nonReentrant
        onlyHolder(from)
        onlyEOA
    {
        uint256 fees = initialNFTValue * amount;
        if (openNextStage == false) revert InvalidOperation();
        if (_balanceOfNFT(msg.sender) < amount) revert InsufficientBalance();
        if (balanceOf(msg.sender) < fees) revert InsufficientBalance();

        uint256 totalReward = 0;
        uint256 lastSupply = _totalNFTSupply();

        for (uint256 i = 0; i < amount; i++) {
            totalReward += burnReward();
            unchecked {
                lastSupply--;
            }
            initialNFTValue +=
                ((initialNFTValue * BURN_REWARD_RATIO * BURNT_ALLOC_RATIO) /
                    lastSupply) /
                10**8;
        }

        _burn(msg.sender, amount * _NFTUnit(), true);
        _transfer(address(this), msg.sender, totalReward - fees);

        emit Burn(amount, totalReward, fees);
    }

    function burnReward() public view returns (uint256) {
        return (initialNFTValue * BURN_REWARD_RATIO) / 10000;
    }

    /* ------------------ */
    /*       Unlock       */
    /* ------------------ */

    function unlock(address from) public nonReentrant onlyHolder(from) onlyEOA {
        if (openUnlock == false) revert InvalidOperation();
        _unlock(from);
    }

    function lockedBalance(address from)
        public
        view
        returns (uint256)
    {
        return _getDN404Storage().addressData[from].lockedBalance;
    }

    /* ------------------ */
    /*         DEV        */
    /* ------------------ */

    function reserve(uint256 amount) public {
        if (msg.sender != team) {
            revert InvalidSender();
        }
        if (_totalNFTSupply() + amount > _getMaxNFTSupply()) {
            revert TotalSupplyOverflow();
        }

        _mint(msg.sender, amount * _NFTUnit());
    }

    function setBaseURI(string calldata baseURI_) public onlyOwner {
        _baseURI = baseURI_;
    }

    function setPrices(uint120 price_) public onlyOwner {
        price = price_;
    }

    function setMaxBuy(uint256 maxBuy_) public onlyOwner {
        maxBuy = maxBuy_;
    }

    function setMaxNFTSupply(uint256 value) public onlyOwner {
        _setMaxNFTSupply(value);
    }

    function setTeamWallet(address a) public onlyOwner {
        team = a;
    }

    function setSigner(address a) public onlyOwner {
        signer = a;
    }

    function toggleOpenSetSkipNFT() public onlyOwner {
        openSetSkipNFT = !openSetSkipNFT;
    }

    function toggleOpenUnlock() public onlyOwner {
        openUnlock = !openUnlock;
    }

    function toggleOpenNextStage() public onlyOwner {
        openNextStage = !openNextStage;
    }

    function toggleOpenBuy() public onlyOwner {
        openBuy = !openBuy;
    }

    function withdraw() public onlyOwner nonReentrant {
        SafeTransferLib.safeTransferAllETH(team);
    }

    function name() public view override returns (string memory) {
        return _name;
    }

    function symbol() public view override returns (string memory) {
        return _symbol;
    }

    function _unit() internal view override returns (uint256) {
        return initialNFTValue;
    }

    function tokenURI(uint256 tokenId)
        public
        view
        override
        returns (string memory result)
    {
        if (bytes(_baseURI).length != 0) {
            result = string(
                abi.encodePacked(_baseURI, LibString.toString(tokenId))
            );
        }
    }

    function getTokensOfOwner(address a)
        public
        view
        returns (uint256[] memory)
    {
        return _tokensOfWithChecks(a);
    }

    function getNFTSupply() public view returns (uint256) {
        return _totalNFTSupply();
    }

    function lastNFTUnit(uint256 id) public view returns (uint256) {
        return _get(_getDN404Storage().NFTUnit, id);
    }

    function addressAlias(address a) public view returns (uint32) {
        return _getDN404Storage().addressData[a].addressAlias;
    }

    /* ---------------------- */
    /*   Override Operation   */
    /* ---------------------- */

    // setSkipNFT lokced before all NFT minted.
    function setSkipNFT(bool skip) public override returns (bool) {
        if (openSetSkipNFT == false) revert InvalidOperation();

        _setSkipNFT(msg.sender, skip);
        return true;
    }
}

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

/// @notice Gas optimized ECDSA wrapper.
/// @author Solady (https://github.com/vectorized/solady/blob/main/src/utils/ECDSA.sol)
/// @author Modified from Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/ECDSA.sol)
/// @author Modified from OpenZeppelin (https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/ECDSA.sol)
///
/// @dev Note:
/// - The recovery functions use the ecrecover precompile (0x1).
/// - As of Solady version 0.0.68, the `recover` variants will revert upon recovery failure.
///   This is for more safety by default.
///   Use the `tryRecover` variants if you need to get the zero address back
///   upon recovery failure instead.
/// - As of Solady version 0.0.134, all `bytes signature` variants accept both
///   regular 65-byte `(r, s, v)` and EIP-2098 `(r, vs)` short form signatures.
///   See: https://eips.ethereum.org/EIPS/eip-2098
///   This is for calldata efficiency on smart accounts prevalent on L2s.
///
/// WARNING! Do NOT use signatures as unique identifiers:
/// - Use a nonce in the digest to prevent replay attacks on the same contract.
/// - Use EIP-712 for the digest to prevent replay attacks across different chains and contracts.
///   EIP-712 also enables readable signing of typed data for better user safety.
/// This implementation does NOT check if a signature is non-malleable.
library ECDSA {
    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                        CUSTOM ERRORS                       */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev The signature is invalid.
    error InvalidSignature();

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                    RECOVERY OPERATIONS                     */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Recovers the signer's address from a message digest `hash`, and the `signature`.
    function recover(bytes32 hash, bytes memory signature) internal view returns (address result) {
        /// @solidity memory-safe-assembly
        assembly {
            result := 1
            let m := mload(0x40) // Cache the free memory pointer.
            for {} 1 {} {
                mstore(0x00, hash)
                mstore(0x40, mload(add(signature, 0x20))) // `r`.
                if eq(mload(signature), 64) {
                    let vs := mload(add(signature, 0x40))
                    mstore(0x20, add(shr(255, vs), 27)) // `v`.
                    mstore(0x60, shr(1, shl(1, vs))) // `s`.
                    break
                }
                if eq(mload(signature), 65) {
                    mstore(0x20, byte(0, mload(add(signature, 0x60)))) // `v`.
                    mstore(0x60, mload(add(signature, 0x40))) // `s`.
                    break
                }
                result := 0
                break
            }
            result :=
                mload(
                    staticcall(
                        gas(), // Amount of gas left for the transaction.
                        result, // Address of `ecrecover`.
                        0x00, // Start of input.
                        0x80, // Size of input.
                        0x01, // Start of output.
                        0x20 // Size of output.
                    )
                )
            // `returndatasize()` will be `0x20` upon success, and `0x00` otherwise.
            if iszero(returndatasize()) {
                mstore(0x00, 0x8baa579f) // `InvalidSignature()`.
                revert(0x1c, 0x04)
            }
            mstore(0x60, 0) // Restore the zero slot.
            mstore(0x40, m) // Restore the free memory pointer.
        }
    }

    /// @dev Recovers the signer's address from a message digest `hash`, and the `signature`.
    function recoverCalldata(bytes32 hash, bytes calldata signature)
        internal
        view
        returns (address result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            result := 1
            let m := mload(0x40) // Cache the free memory pointer.
            mstore(0x00, hash)
            for {} 1 {} {
                if eq(signature.length, 64) {
                    let vs := calldataload(add(signature.offset, 0x20))
                    mstore(0x20, add(shr(255, vs), 27)) // `v`.
                    mstore(0x40, calldataload(signature.offset)) // `r`.
                    mstore(0x60, shr(1, shl(1, vs))) // `s`.
                    break
                }
                if eq(signature.length, 65) {
                    mstore(0x20, byte(0, calldataload(add(signature.offset, 0x40)))) // `v`.
                    calldatacopy(0x40, signature.offset, 0x40) // Copy `r` and `s`.
                    break
                }
                result := 0
                break
            }
            result :=
                mload(
                    staticcall(
                        gas(), // Amount of gas left for the transaction.
                        result, // Address of `ecrecover`.
                        0x00, // Start of input.
                        0x80, // Size of input.
                        0x01, // Start of output.
                        0x20 // Size of output.
                    )
                )
            // `returndatasize()` will be `0x20` upon success, and `0x00` otherwise.
            if iszero(returndatasize()) {
                mstore(0x00, 0x8baa579f) // `InvalidSignature()`.
                revert(0x1c, 0x04)
            }
            mstore(0x60, 0) // Restore the zero slot.
            mstore(0x40, m) // Restore the free memory pointer.
        }
    }

    /// @dev Recovers the signer's address from a message digest `hash`,
    /// and the EIP-2098 short form signature defined by `r` and `vs`.
    function recover(bytes32 hash, bytes32 r, bytes32 vs) internal view returns (address result) {
        /// @solidity memory-safe-assembly
        assembly {
            let m := mload(0x40) // Cache the free memory pointer.
            mstore(0x00, hash)
            mstore(0x20, add(shr(255, vs), 27)) // `v`.
            mstore(0x40, r)
            mstore(0x60, shr(1, shl(1, vs))) // `s`.
            result :=
                mload(
                    staticcall(
                        gas(), // Amount of gas left for the transaction.
                        1, // Address of `ecrecover`.
                        0x00, // Start of input.
                        0x80, // Size of input.
                        0x01, // Start of output.
                        0x20 // Size of output.
                    )
                )
            // `returndatasize()` will be `0x20` upon success, and `0x00` otherwise.
            if iszero(returndatasize()) {
                mstore(0x00, 0x8baa579f) // `InvalidSignature()`.
                revert(0x1c, 0x04)
            }
            mstore(0x60, 0) // Restore the zero slot.
            mstore(0x40, m) // Restore the free memory pointer.
        }
    }

    /// @dev Recovers the signer's address from a message digest `hash`,
    /// and the signature defined by `v`, `r`, `s`.
    function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s)
        internal
        view
        returns (address result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let m := mload(0x40) // Cache the free memory pointer.
            mstore(0x00, hash)
            mstore(0x20, and(v, 0xff))
            mstore(0x40, r)
            mstore(0x60, s)
            result :=
                mload(
                    staticcall(
                        gas(), // Amount of gas left for the transaction.
                        1, // Address of `ecrecover`.
                        0x00, // Start of input.
                        0x80, // Size of input.
                        0x01, // Start of output.
                        0x20 // Size of output.
                    )
                )
            // `returndatasize()` will be `0x20` upon success, and `0x00` otherwise.
            if iszero(returndatasize()) {
                mstore(0x00, 0x8baa579f) // `InvalidSignature()`.
                revert(0x1c, 0x04)
            }
            mstore(0x60, 0) // Restore the zero slot.
            mstore(0x40, m) // Restore the free memory pointer.
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   TRY-RECOVER OPERATIONS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    // WARNING!
    // These functions will NOT revert upon recovery failure.
    // Instead, they will return the zero address upon recovery failure.
    // It is critical that the returned address is NEVER compared against
    // a zero address (e.g. an uninitialized address variable).

    /// @dev Recovers the signer's address from a message digest `hash`, and the `signature`.
    function tryRecover(bytes32 hash, bytes memory signature)
        internal
        view
        returns (address result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            result := 1
            let m := mload(0x40) // Cache the free memory pointer.
            for {} 1 {} {
                mstore(0x00, hash)
                mstore(0x40, mload(add(signature, 0x20))) // `r`.
                if eq(mload(signature), 64) {
                    let vs := mload(add(signature, 0x40))
                    mstore(0x20, add(shr(255, vs), 27)) // `v`.
                    mstore(0x60, shr(1, shl(1, vs))) // `s`.
                    break
                }
                if eq(mload(signature), 65) {
                    mstore(0x20, byte(0, mload(add(signature, 0x60)))) // `v`.
                    mstore(0x60, mload(add(signature, 0x40))) // `s`.
                    break
                }
                result := 0
                break
            }
            pop(
                staticcall(
                    gas(), // Amount of gas left for the transaction.
                    result, // Address of `ecrecover`.
                    0x00, // Start of input.
                    0x80, // Size of input.
                    0x40, // Start of output.
                    0x20 // Size of output.
                )
            )
            mstore(0x60, 0) // Restore the zero slot.
            // `returndatasize()` will be `0x20` upon success, and `0x00` otherwise.
            result := mload(xor(0x60, returndatasize()))
            mstore(0x40, m) // Restore the free memory pointer.
        }
    }

    /// @dev Recovers the signer's address from a message digest `hash`, and the `signature`.
    function tryRecoverCalldata(bytes32 hash, bytes calldata signature)
        internal
        view
        returns (address result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            result := 1
            let m := mload(0x40) // Cache the free memory pointer.
            mstore(0x00, hash)
            for {} 1 {} {
                if eq(signature.length, 64) {
                    let vs := calldataload(add(signature.offset, 0x20))
                    mstore(0x20, add(shr(255, vs), 27)) // `v`.
                    mstore(0x40, calldataload(signature.offset)) // `r`.
                    mstore(0x60, shr(1, shl(1, vs))) // `s`.
                    break
                }
                if eq(signature.length, 65) {
                    mstore(0x20, byte(0, calldataload(add(signature.offset, 0x40)))) // `v`.
                    calldatacopy(0x40, signature.offset, 0x40) // Copy `r` and `s`.
                    break
                }
                result := 0
                break
            }
            pop(
                staticcall(
                    gas(), // Amount of gas left for the transaction.
                    result, // Address of `ecrecover`.
                    0x00, // Start of input.
                    0x80, // Size of input.
                    0x40, // Start of output.
                    0x20 // Size of output.
                )
            )
            mstore(0x60, 0) // Restore the zero slot.
            // `returndatasize()` will be `0x20` upon success, and `0x00` otherwise.
            result := mload(xor(0x60, returndatasize()))
            mstore(0x40, m) // Restore the free memory pointer.
        }
    }

    /// @dev Recovers the signer's address from a message digest `hash`,
    /// and the EIP-2098 short form signature defined by `r` and `vs`.
    function tryRecover(bytes32 hash, bytes32 r, bytes32 vs)
        internal
        view
        returns (address result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let m := mload(0x40) // Cache the free memory pointer.
            mstore(0x00, hash)
            mstore(0x20, add(shr(255, vs), 27)) // `v`.
            mstore(0x40, r)
            mstore(0x60, shr(1, shl(1, vs))) // `s`.
            pop(
                staticcall(
                    gas(), // Amount of gas left for the transaction.
                    1, // Address of `ecrecover`.
                    0x00, // Start of input.
                    0x80, // Size of input.
                    0x40, // Start of output.
                    0x20 // Size of output.
                )
            )
            mstore(0x60, 0) // Restore the zero slot.
            // `returndatasize()` will be `0x20` upon success, and `0x00` otherwise.
            result := mload(xor(0x60, returndatasize()))
            mstore(0x40, m) // Restore the free memory pointer.
        }
    }

    /// @dev Recovers the signer's address from a message digest `hash`,
    /// and the signature defined by `v`, `r`, `s`.
    function tryRecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s)
        internal
        view
        returns (address result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let m := mload(0x40) // Cache the free memory pointer.
            mstore(0x00, hash)
            mstore(0x20, and(v, 0xff))
            mstore(0x40, r)
            mstore(0x60, s)
            pop(
                staticcall(
                    gas(), // Amount of gas left for the transaction.
                    1, // Address of `ecrecover`.
                    0x00, // Start of input.
                    0x80, // Size of input.
                    0x40, // Start of output.
                    0x20 // Size of output.
                )
            )
            mstore(0x60, 0) // Restore the zero slot.
            // `returndatasize()` will be `0x20` upon success, and `0x00` otherwise.
            result := mload(xor(0x60, returndatasize()))
            mstore(0x40, m) // Restore the free memory pointer.
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                     HASHING OPERATIONS                     */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns an Ethereum Signed Message, created from a `hash`.
    /// This produces a hash corresponding to the one signed with the
    /// [`eth_sign`](https://eth.wiki/json-rpc/API#eth_sign)
    /// JSON-RPC method as part of EIP-191.
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32 result) {
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x20, hash) // Store into scratch space for keccak256.
            mstore(0x00, "\x00\x00\x00\x00\x19Ethereum Signed Message:\n32") // 28 bytes.
            result := keccak256(0x04, 0x3c) // `32 * 2 - (32 - 28) = 60 = 0x3c`.
        }
    }

    /// @dev Returns an Ethereum Signed Message, created from `s`.
    /// This produces a hash corresponding to the one signed with the
    /// [`eth_sign`](https://eth.wiki/json-rpc/API#eth_sign)
    /// JSON-RPC method as part of EIP-191.
    /// Note: Supports lengths of `s` up to 999999 bytes.
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32 result) {
        /// @solidity memory-safe-assembly
        assembly {
            let sLength := mload(s)
            let o := 0x20
            mstore(o, "\x19Ethereum Signed Message:\n") // 26 bytes, zero-right-padded.
            mstore(0x00, 0x00)
            // Convert the `s.length` to ASCII decimal representation: `base10(s.length)`.
            for { let temp := sLength } 1 {} {
                o := sub(o, 1)
                mstore8(o, add(48, mod(temp, 10)))
                temp := div(temp, 10)
                if iszero(temp) { break }
            }
            let n := sub(0x3a, o) // Header length: `26 + 32 - o`.
            // Throw an out-of-offset error (consumes all gas) if the header exceeds 32 bytes.
            returndatacopy(returndatasize(), returndatasize(), gt(n, 0x20))
            mstore(s, or(mload(0x00), mload(n))) // Temporarily store the header.
            result := keccak256(add(s, sub(0x20, n)), add(n, sLength))
            mstore(s, sLength) // Restore the length.
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   EMPTY CALLDATA HELPERS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns an empty calldata bytes.
    function emptySignature() internal pure returns (bytes calldata signature) {
        /// @solidity memory-safe-assembly
        assembly {
            signature.length := 0
        }
    }
}

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

/// @notice Library for converting numbers into strings and other string operations.
/// @author Solady (https://github.com/vectorized/solady/blob/main/src/utils/LibString.sol)
/// @author Modified from Solmate (https://github.com/transmissions11/solmate/blob/main/src/utils/LibString.sol)
///
/// @dev Note:
/// For performance and bytecode compactness, most of the string operations are restricted to
/// byte strings (7-bit ASCII), except where otherwise specified.
/// Usage of byte string operations on charsets with runes spanning two or more bytes
/// can lead to undefined behavior.
library LibString {
    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                        CUSTOM ERRORS                       */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev The length of the output is too small to contain all the hex digits.
    error HexLengthInsufficient();

    /// @dev The length of the string is more than 32 bytes.
    error TooBigForSmallString();

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

    /// @dev The constant returned when the `search` is not found in the string.
    uint256 internal constant NOT_FOUND = type(uint256).max;

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                     DECIMAL OPERATIONS                     */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns the base 10 decimal representation of `value`.
    function toString(uint256 value) internal pure returns (string memory str) {
        /// @solidity memory-safe-assembly
        assembly {
            // The maximum value of a uint256 contains 78 digits (1 byte per digit), but
            // we allocate 0xa0 bytes to keep the free memory pointer 32-byte word aligned.
            // We will need 1 word for the trailing zeros padding, 1 word for the length,
            // and 3 words for a maximum of 78 digits.
            str := add(mload(0x40), 0x80)
            // Update the free memory pointer to allocate.
            mstore(0x40, add(str, 0x20))
            // Zeroize the slot after the string.
            mstore(str, 0)

            // Cache the end of the memory to calculate the length later.
            let end := str

            let w := not(0) // Tsk.
            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            for { let temp := value } 1 {} {
                str := add(str, w) // `sub(str, 1)`.
                // Write the character to the pointer.
                // The ASCII index of the '0' character is 48.
                mstore8(str, add(48, mod(temp, 10)))
                // Keep dividing `temp` until zero.
                temp := div(temp, 10)
                if iszero(temp) { break }
            }

            let length := sub(end, str)
            // Move the pointer 32 bytes leftwards to make room for the length.
            str := sub(str, 0x20)
            // Store the length.
            mstore(str, length)
        }
    }

    /// @dev Returns the base 10 decimal representation of `value`.
    function toString(int256 value) internal pure returns (string memory str) {
        if (value >= 0) {
            return toString(uint256(value));
        }
        unchecked {
            str = toString(~uint256(value) + 1);
        }
        /// @solidity memory-safe-assembly
        assembly {
            // We still have some spare memory space on the left,
            // as we have allocated 3 words (96 bytes) for up to 78 digits.
            let length := mload(str) // Load the string length.
            mstore(str, 0x2d) // Store the '-' character.
            str := sub(str, 1) // Move back the string pointer by a byte.
            mstore(str, add(length, 1)) // Update the string length.
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   HEXADECIMAL OPERATIONS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns the hexadecimal representation of `value`,
    /// left-padded to an input length of `length` bytes.
    /// The output is prefixed with "0x" encoded using 2 hexadecimal digits per byte,
    /// giving a total length of `length * 2 + 2` bytes.
    /// Reverts if `length` is too small for the output to contain all the digits.
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(value, length);
        /// @solidity memory-safe-assembly
        assembly {
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(str, 0x3078) // Write the "0x" prefix.
            str := sub(str, 2) // Move the pointer.
            mstore(str, strLength) // Write the length.
        }
    }

    /// @dev Returns the hexadecimal representation of `value`,
    /// left-padded to an input length of `length` bytes.
    /// The output is prefixed with "0x" encoded using 2 hexadecimal digits per byte,
    /// giving a total length of `length * 2` bytes.
    /// Reverts if `length` is too small for the output to contain all the digits.
    function toHexStringNoPrefix(uint256 value, uint256 length)
        internal
        pure
        returns (string memory str)
    {
        /// @solidity memory-safe-assembly
        assembly {
            // We need 0x20 bytes for the trailing zeros padding, `length * 2` bytes
            // for the digits, 0x02 bytes for the prefix, and 0x20 bytes for the length.
            // We add 0x20 to the total and round down to a multiple of 0x20.
            // (0x20 + 0x20 + 0x02 + 0x20) = 0x62.
            str := add(mload(0x40), and(add(shl(1, length), 0x42), not(0x1f)))
            // Allocate the memory.
            mstore(0x40, add(str, 0x20))
            // Zeroize the slot after the string.
            mstore(str, 0)

            // Cache the end to calculate the length later.
            let end := str
            // Store "0123456789abcdef" in scratch space.
            mstore(0x0f, 0x30313233343536373839616263646566)

            let start := sub(str, add(length, length))
            let w := not(1) // Tsk.
            let temp := value
            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            for {} 1 {} {
                str := add(str, w) // `sub(str, 2)`.
                mstore8(add(str, 1), mload(and(temp, 15)))
                mstore8(str, mload(and(shr(4, temp), 15)))
                temp := shr(8, temp)
                if iszero(xor(str, start)) { break }
            }

            if temp {
                mstore(0x00, 0x2194895a) // `HexLengthInsufficient()`.
                revert(0x1c, 0x04)
            }

            // Compute the string's length.
            let strLength := sub(end, str)
            // Move the pointer and write the length.
            str := sub(str, 0x20)
            mstore(str, strLength)
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is prefixed with "0x" and encoded using 2 hexadecimal digits per byte.
    /// As address are 20 bytes long, the output will left-padded to have
    /// a length of `20 * 2 + 2` bytes.
    function toHexString(uint256 value) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(value);
        /// @solidity memory-safe-assembly
        assembly {
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(str, 0x3078) // Write the "0x" prefix.
            str := sub(str, 2) // Move the pointer.
            mstore(str, strLength) // Write the length.
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is prefixed with "0x".
    /// The output excludes leading "0" from the `toHexString` output.
    /// `0x00: "0x0", 0x01: "0x1", 0x12: "0x12", 0x123: "0x123"`.
    function toMinimalHexString(uint256 value) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(value);
        /// @solidity memory-safe-assembly
        assembly {
            let o := eq(byte(0, mload(add(str, 0x20))), 0x30) // Whether leading zero is present.
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(add(str, o), 0x3078) // Write the "0x" prefix, accounting for leading zero.
            str := sub(add(str, o), 2) // Move the pointer, accounting for leading zero.
            mstore(str, sub(strLength, o)) // Write the length, accounting for leading zero.
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output excludes leading "0" from the `toHexStringNoPrefix` output.
    /// `0x00: "0", 0x01: "1", 0x12: "12", 0x123: "123"`.
    function toMinimalHexStringNoPrefix(uint256 value) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(value);
        /// @solidity memory-safe-assembly
        assembly {
            let o := eq(byte(0, mload(add(str, 0x20))), 0x30) // Whether leading zero is present.
            let strLength := mload(str) // Get the length.
            str := add(str, o) // Move the pointer, accounting for leading zero.
            mstore(str, sub(strLength, o)) // Write the length, accounting for leading zero.
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is encoded using 2 hexadecimal digits per byte.
    /// As address are 20 bytes long, the output will left-padded to have
    /// a length of `20 * 2` bytes.
    function toHexStringNoPrefix(uint256 value) internal pure returns (string memory str) {
        /// @solidity memory-safe-assembly
        assembly {
            // We need 0x20 bytes for the trailing zeros padding, 0x20 bytes for the length,
            // 0x02 bytes for the prefix, and 0x40 bytes for the digits.
            // The next multiple of 0x20 above (0x20 + 0x20 + 0x02 + 0x40) is 0xa0.
            str := add(mload(0x40), 0x80)
            // Allocate the memory.
            mstore(0x40, add(str, 0x20))
            // Zeroize the slot after the string.
            mstore(str, 0)

            // Cache the end to calculate the length later.
            let end := str
            // Store "0123456789abcdef" in scratch space.
            mstore(0x0f, 0x30313233343536373839616263646566)

            let w := not(1) // Tsk.
            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            for { let temp := value } 1 {} {
                str := add(str, w) // `sub(str, 2)`.
                mstore8(add(str, 1), mload(and(temp, 15)))
                mstore8(str, mload(and(shr(4, temp), 15)))
                temp := shr(8, temp)
                if iszero(temp) { break }
            }

            // Compute the string's length.
            let strLength := sub(end, str)
            // Move the pointer and write the length.
            str := sub(str, 0x20)
            mstore(str, strLength)
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is prefixed with "0x", encoded using 2 hexadecimal digits per byte,
    /// and the alphabets are capitalized conditionally according to
    /// https://eips.ethereum.org/EIPS/eip-55
    function toHexStringChecksummed(address value) internal pure returns (string memory str) {
        str = toHexString(value);
        /// @solidity memory-safe-assembly
        assembly {
            let mask := shl(6, div(not(0), 255)) // `0b010000000100000000 ...`
            let o := add(str, 0x22)
            let hashed := and(keccak256(o, 40), mul(34, mask)) // `0b10001000 ... `
            let t := shl(240, 136) // `0b10001000 << 240`
            for { let i := 0 } 1 {} {
                mstore(add(i, i), mul(t, byte(i, hashed)))
                i := add(i, 1)
                if eq(i, 20) { break }
            }
            mstore(o, xor(mload(o), shr(1, and(mload(0x00), and(mload(o), mask)))))
            o := add(o, 0x20)
            mstore(o, xor(mload(o), shr(1, and(mload(0x20), and(mload(o), mask)))))
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is prefixed with "0x" and encoded using 2 hexadecimal digits per byte.
    function toHexString(address value) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(value);
        /// @solidity memory-safe-assembly
        assembly {
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(str, 0x3078) // Write the "0x" prefix.
            str := sub(str, 2) // Move the pointer.
            mstore(str, strLength) // Write the length.
        }
    }

    /// @dev Returns the hexadecimal representation of `value`.
    /// The output is encoded using 2 hexadecimal digits per byte.
    function toHexStringNoPrefix(address value) internal pure returns (string memory str) {
        /// @solidity memory-safe-assembly
        assembly {
            str := mload(0x40)

            // Allocate the memory.
            // We need 0x20 bytes for the trailing zeros padding, 0x20 bytes for the length,
            // 0x02 bytes for the prefix, and 0x28 bytes for the digits.
            // The next multiple of 0x20 above (0x20 + 0x20 + 0x02 + 0x28) is 0x80.
            mstore(0x40, add(str, 0x80))

            // Store "0123456789abcdef" in scratch space.
            mstore(0x0f, 0x30313233343536373839616263646566)

            str := add(str, 2)
            mstore(str, 40)

            let o := add(str, 0x20)
            mstore(add(o, 40), 0)

            value := shl(96, value)

            // We write the string from rightmost digit to leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            for { let i := 0 } 1 {} {
                let p := add(o, add(i, i))
                let temp := byte(i, value)
                mstore8(add(p, 1), mload(and(temp, 15)))
                mstore8(p, mload(shr(4, temp)))
                i := add(i, 1)
                if eq(i, 20) { break }
            }
        }
    }

    /// @dev Returns the hex encoded string from the raw bytes.
    /// The output is encoded using 2 hexadecimal digits per byte.
    function toHexString(bytes memory raw) internal pure returns (string memory str) {
        str = toHexStringNoPrefix(raw);
        /// @solidity memory-safe-assembly
        assembly {
            let strLength := add(mload(str), 2) // Compute the length.
            mstore(str, 0x3078) // Write the "0x" prefix.
            str := sub(str, 2) // Move the pointer.
            mstore(str, strLength) // Write the length.
        }
    }

    /// @dev Returns the hex encoded string from the raw bytes.
    /// The output is encoded using 2 hexadecimal digits per byte.
    function toHexStringNoPrefix(bytes memory raw) internal pure returns (string memory str) {
        /// @solidity memory-safe-assembly
        assembly {
            let length := mload(raw)
            str := add(mload(0x40), 2) // Skip 2 bytes for the optional prefix.
            mstore(str, add(length, length)) // Store the length of the output.

            // Store "0123456789abcdef" in scratch space.
            mstore(0x0f, 0x30313233343536373839616263646566)

            let o := add(str, 0x20)
            let end := add(raw, length)

            for {} iszero(eq(raw, end)) {} {
                raw := add(raw, 1)
                mstore8(add(o, 1), mload(and(mload(raw), 15)))
                mstore8(o, mload(and(shr(4, mload(raw)), 15)))
                o := add(o, 2)
            }
            mstore(o, 0) // Zeroize the slot after the string.
            mstore(0x40, add(o, 0x20)) // Allocate the memory.
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   RUNE STRING OPERATIONS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    /// @dev Returns the number of UTF characters in the string.
    function runeCount(string memory s) internal pure returns (uint256 result) {
        /// @solidity memory-safe-assembly
        assembly {
            if mload(s) {
                mstore(0x00, div(not(0), 255))
                mstore(0x20, 0x0202020202020202020202020202020202020202020202020303030304040506)
                let o := add(s, 0x20)
                let end := add(o, mload(s))
                for { result := 1 } 1 { result := add(result, 1) } {
                    o := add(o, byte(0, mload(shr(250, mload(o)))))
                    if iszero(lt(o, end)) { break }
                }
            }
        }
    }

    /// @dev Returns if this string is a 7-bit ASCII string.
    /// (i.e. all characters codes are in [0..127])
    function is7BitASCII(string memory s) internal pure returns (bool result) {
        /// @solidity memory-safe-assembly
        assembly {
            let mask := shl(7, div(not(0), 255))
            result := 1
            let n := mload(s)
            if n {
                let o := add(s, 0x20)
                let end := add(o, n)
                let last := mload(end)
                mstore(end, 0)
                for {} 1 {} {
                    if and(mask, mload(o)) {
                        result := 0
                        break
                    }
                    o := add(o, 0x20)
                    if iszero(lt(o, end)) { break }
                }
                mstore(end, last)
            }
        }
    }

    /*´:°•.°+.*•´.*:˚.°*.˚•´.°:°•.°•.*•´.*:˚.°*.˚•´.°:°•.°+.*•´.*:*/
    /*                   BYTE STRING OPERATIONS                   */
    /*.•°:°.´+˚.*°.˚:*.´•*.+°.•°:´*.´•*.•°.•°:°.´:•˚°.*°.˚:*.´+°.•*/

    // For performance and bytecode compactness, byte string operations are restricted
    // to 7-bit ASCII strings. All offsets are byte offsets, not UTF character offsets.
    // Usage of byte string operations on charsets with runes spanning two or more bytes
    // can lead to undefined behavior.

    /// @dev Returns `subject` all occurrences of `search` replaced with `replacement`.
    function replace(string memory subject, string memory search, string memory replacement)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let subjectLength := mload(subject)
            let searchLength := mload(search)
            let replacementLength := mload(replacement)

            subject := add(subject, 0x20)
            search := add(search, 0x20)
            replacement := add(replacement, 0x20)
            result := add(mload(0x40), 0x20)

            let subjectEnd := add(subject, subjectLength)
            if iszero(gt(searchLength, subjectLength)) {
                let subjectSearchEnd := add(sub(subjectEnd, searchLength), 1)
                let h := 0
                if iszero(lt(searchLength, 0x20)) { h := keccak256(search, searchLength) }
                let m := shl(3, sub(0x20, and(searchLength, 0x1f)))
                let s := mload(search)
                for {} 1 {} {
                    let t := mload(subject)
                    // Whether the first `searchLength % 32` bytes of
                    // `subject` and `search` matches.
                    if iszero(shr(m, xor(t, s))) {
                        if h {
                            if iszero(eq(keccak256(subject, searchLength), h)) {
                                mstore(result, t)
                                result := add(result, 1)
                                subject := add(subject, 1)
                                if iszero(lt(subject, subjectSearchEnd)) { break }
                                continue
                            }
                        }
                        // Copy the `replacement` one word at a time.
                        for { let o := 0 } 1 {} {
                            mstore(add(result, o), mload(add(replacement, o)))
                            o := add(o, 0x20)
                            if iszero(lt(o, replacementLength)) { break }
                        }
                        result := add(result, replacementLength)
                        subject := add(subject, searchLength)
                        if searchLength {
                            if iszero(lt(subject, subjectSearchEnd)) { break }
                            continue
                        }
                    }
                    mstore(result, t)
                    result := add(result, 1)
                    subject := add(subject, 1)
                    if iszero(lt(subject, subjectSearchEnd)) { break }
                }
            }

            let resultRemainder := result
            result := add(mload(0x40), 0x20)
            let k := add(sub(resultRemainder, result), sub(subjectEnd, subject))
            // Copy the rest of the string one word at a time.
            for {} lt(subject, subjectEnd) {} {
                mstore(resultRemainder, mload(subject))
                resultRemainder := add(resultRemainder, 0x20)
                subject := add(subject, 0x20)
            }
            result := sub(result, 0x20)
            let last := add(add(result, 0x20), k) // Zeroize the slot after the string.
            mstore(last, 0)
            mstore(0x40, add(last, 0x20)) // Allocate the memory.
            mstore(result, k) // Store the length.
        }
    }

    /// @dev Returns the byte index of the first location of `search` in `subject`,
    /// searching from left to right, starting from `from`.
    /// Returns `NOT_FOUND` (i.e. `type(uint256).max`) if the `search` is not found.
    function indexOf(string memory subject, string memory search, uint256 from)
        internal
        pure
        returns (uint256 result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            for { let subjectLength := mload(subject) } 1 {} {
                if iszero(mload(search)) {
                    if iszero(gt(from, subjectLength)) {
                        result := from
                        break
                    }
                    result := subjectLength
                    break
                }
                let searchLength := mload(search)
                let subjectStart := add(subject, 0x20)

                result := not(0) // Initialize to `NOT_FOUND`.

                subject := add(subjectStart, from)
                let end := add(sub(add(subjectStart, subjectLength), searchLength), 1)

                let m := shl(3, sub(0x20, and(searchLength, 0x1f)))
                let s := mload(add(search, 0x20))

                if iszero(and(lt(subject, end), lt(from, subjectLength))) { break }

                if iszero(lt(searchLength, 0x20)) {
                    for { let h := keccak256(add(search, 0x20), searchLength) } 1 {} {
                        if iszero(shr(m, xor(mload(subject), s))) {
                            if eq(keccak256(subject, searchLength), h) {
                                result := sub(subject, subjectStart)
                                break
                            }
                        }
                        subject := add(subject, 1)
                        if iszero(lt(subject, end)) { break }
                    }
                    break
                }
                for {} 1 {} {
                    if iszero(shr(m, xor(mload(subject), s))) {
                        result := sub(subject, subjectStart)
                        break
                    }
                    subject := add(subject, 1)
                    if iszero(lt(subject, end)) { break }
                }
                break
            }
        }
    }

    /// @dev Returns the byte index of the first location of `search` in `subject`,
    /// searching from left to right.
    /// Returns `NOT_FOUND` (i.e. `type(uint256).max`) if the `search` is not found.
    function indexOf(string memory subject, string memory search)
        internal
        pure
        returns (uint256 result)
    {
        result = indexOf(subject, search, 0);
    }

    /// @dev Returns the byte index of the first location of `search` in `subject`,
    /// searching from right to left, starting from `from`.
    /// Returns `NOT_FOUND` (i.e. `type(uint256).max`) if the `search` is not found.
    function lastIndexOf(string memory subject, string memory search, uint256 from)
        internal
        pure
        returns (uint256 result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            for {} 1 {} {
                result := not(0) // Initialize to `NOT_FOUND`.
                let searchLength := mload(search)
                if gt(searchLength, mload(subject)) { break }
                let w := result

                let fromMax := sub(mload(subject), searchLength)
                if iszero(gt(fromMax, from)) { from := fromMax }

                let end := add(add(subject, 0x20), w)
                subject := add(add(subject, 0x20), from)
                if iszero(gt(subject, end)) { break }
                // As this function is not too often used,
                // we shall simply use keccak256 for smaller bytecode size.
                for { let h := keccak256(add(search, 0x20), searchLength) } 1 {} {
                    if eq(keccak256(subject, searchLength), h) {
                        result := sub(subject, add(end, 1))
                        break
                    }
                    subject := add(subject, w) // `sub(subject, 1)`.
                    if iszero(gt(subject, end)) { break }
                }
                break
            }
        }
    }

    /// @dev Returns the byte index of the first location of `search` in `subject`,
    /// searching from right to left.
    /// Returns `NOT_FOUND` (i.e. `type(uint256).max`) if the `search` is not found.
    function lastIndexOf(string memory subject, string memory search)
        internal
        pure
        returns (uint256 result)
    {
        result = lastIndexOf(subject, search, uint256(int256(-1)));
    }

    /// @dev Returns true if `search` is found in `subject`, false otherwise.
    function contains(string memory subject, string memory search) internal pure returns (bool) {
        return indexOf(subject, search) != NOT_FOUND;
    }

    /// @dev Returns whether `subject` starts with `search`.
    function startsWith(string memory subject, string memory search)
        internal
        pure
        returns (bool result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let searchLength := mload(search)
            // Just using keccak256 directly is actually cheaper.
            // forgefmt: disable-next-item
            result := and(
                iszero(gt(searchLength, mload(subject))),
                eq(
                    keccak256(add(subject, 0x20), searchLength),
                    keccak256(add(search, 0x20), searchLength)
                )
            )
        }
    }

    /// @dev Returns whether `subject` ends with `search`.
    function endsWith(string memory subject, string memory search)
        internal
        pure
        returns (bool result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let searchLength := mload(search)
            let subjectLength := mload(subject)
            // Whether `search` is not longer than `subject`.
            let withinRange := iszero(gt(searchLength, subjectLength))
            // Just using keccak256 directly is actually cheaper.
            // forgefmt: disable-next-item
            result := and(
                withinRange,
                eq(
                    keccak256(
                        // `subject + 0x20 + max(subjectLength - searchLength, 0)`.
                        add(add(subject, 0x20), mul(withinRange, sub(subjectLength, searchLength))),
                        searchLength
                    ),
                    keccak256(add(search, 0x20), searchLength)
                )
            )
        }
    }

    /// @dev Returns `subject` repeated `times`.
    function repeat(string memory subject, uint256 times)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let subjectLength := mload(subject)
            if iszero(or(iszero(times), iszero(subjectLength))) {
                subject := add(subject, 0x20)
                result := mload(0x40)
                let output := add(result, 0x20)
                for {} 1 {} {
                    // Copy the `subject` one word at a time.
                    for { let o := 0 } 1 {} {
                        mstore(add(output, o), mload(add(subject, o)))
                        o := add(o, 0x20)
                        if iszero(lt(o, subjectLength)) { break }
                    }
                    output := add(output, subjectLength)
                    times := sub(times, 1)
                    if iszero(times) { break }
                }
                mstore(output, 0) // Zeroize the slot after the string.
                let resultLength := sub(output, add(result, 0x20))
                mstore(result, resultLength) // Store the length.
                // Allocate the memory.
                mstore(0x40, add(result, add(resultLength, 0x20)))
            }
        }
    }

    /// @dev Returns a copy of `subject` sliced from `start` to `end` (exclusive).
    /// `start` and `end` are byte offsets.
    function slice(string memory subject, uint256 start, uint256 end)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let subjectLength := mload(subject)
            if iszero(gt(subjectLength, end)) { end := subjectLength }
            if iszero(gt(subjectLength, start)) { start := subjectLength }
            if lt(start, end) {
                result := mload(0x40)
                let resultLength := sub(end, start)
                mstore(result, resultLength)
                subject := add(subject, start)
                let w := not(0x1f)
                // Copy the `subject` one word at a time, backwards.
                for { let o := and(add(resultLength, 0x1f), w) } 1 {} {
                    mstore(add(result, o), mload(add(subject, o)))
                    o := add(o, w) // `sub(o, 0x20)`.
                    if iszero(o) { break }
                }
                // Zeroize the slot after the string.
                mstore(add(add(result, 0x20), resultLength), 0)
                // Allocate memory for the length and the bytes,
                // rounded up to a multiple of 32.
                mstore(0x40, add(result, and(add(resultLength, 0x3f), w)))
            }
        }
    }

    /// @dev Returns a copy of `subject` sliced from `start` to the end of the string.
    /// `start` is a byte offset.
    function slice(string memory subject, uint256 start)
        internal
        pure
        returns (string memory result)
    {
        result = slice(subject, start, uint256(int256(-1)));
    }

    /// @dev Returns all the indices of `search` in `subject`.
    /// The indices are byte offsets.
    function indicesOf(string memory subject, string memory search)
        internal
        pure
        returns (uint256[] memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let subjectLength := mload(subject)
            let searchLength := mload(search)

            if iszero(gt(searchLength, subjectLength)) {
                subject := add(subject, 0x20)
                search := add(search, 0x20)
                result := add(mload(0x40), 0x20)

                let subjectStart := subject
                let subjectSearchEnd := add(sub(add(subject, subjectLength), searchLength), 1)
                let h := 0
                if iszero(lt(searchLength, 0x20)) { h := keccak256(search, searchLength) }
                let m := shl(3, sub(0x20, and(searchLength, 0x1f)))
                let s := mload(search)
                for {} 1 {} {
                    let t := mload(subject)
                    // Whether the first `searchLength % 32` bytes of
                    // `subject` and `search` matches.
                    if iszero(shr(m, xor(t, s))) {
                        if h {
                            if iszero(eq(keccak256(subject, searchLength), h)) {
                                subject := add(subject, 1)
                                if iszero(lt(subject, subjectSearchEnd)) { break }
                                continue
                            }
                        }
                        // Append to `result`.
                        mstore(result, sub(subject, subjectStart))
                        result := add(result, 0x20)
                        // Advance `subject` by `searchLength`.
                        subject := add(subject, searchLength)
                        if searchLength {
                            if iszero(lt(subject, subjectSearchEnd)) { break }
                            continue
                        }
                    }
                    subject := add(subject, 1)
                    if iszero(lt(subject, subjectSearchEnd)) { break }
                }
                let resultEnd := result
                // Assign `result` to the free memory pointer.
                result := mload(0x40)
                // Store the length of `result`.
                mstore(result, shr(5, sub(resultEnd, add(result, 0x20))))
                // Allocate memory for result.
                // We allocate one more word, so this array can be recycled for {split}.
                mstore(0x40, add(resultEnd, 0x20))
            }
        }
    }

    /// @dev Returns a arrays of strings based on the `delimiter` inside of the `subject` string.
    function split(string memory subject, string memory delimiter)
        internal
        pure
        returns (string[] memory result)
    {
        uint256[] memory indices = indicesOf(subject, delimiter);
        /// @solidity memory-safe-assembly
        assembly {
            let w := not(0x1f)
            let indexPtr := add(indices, 0x20)
            let indicesEnd := add(indexPtr, shl(5, add(mload(indices), 1)))
            mstore(add(indicesEnd, w), mload(subject))
            mstore(indices, add(mload(indices), 1))
            let prevIndex := 0
            for {} 1 {} {
                let index := mload(indexPtr)
                mstore(indexPtr, 0x60)
                if iszero(eq(index, prevIndex)) {
                    let element := mload(0x40)
                    let elementLength := sub(index, prevIndex)
                    mstore(element, elementLength)
                    // Copy the `subject` one word at a time, backwards.
                    for { let o := and(add(elementLength, 0x1f), w) } 1 {} {
                        mstore(add(element, o), mload(add(add(subject, prevIndex), o)))
                        o := add(o, w) // `sub(o, 0x20)`.
                        if iszero(o) { break }
                    }
                    // Zeroize the slot after the string.
                    mstore(add(add(element, 0x20), elementLength), 0)
                    // Allocate memory for the length and the bytes,
                    // rounded up to a multiple of 32.
                    mstore(0x40, add(element, and(add(elementLength, 0x3f), w)))
                    // Store the `element` into the array.
                    mstore(indexPtr, element)
                }
                prevIndex := add(index, mload(delimiter))
                indexPtr := add(indexPtr, 0x20)
                if iszero(lt(indexPtr, indicesEnd)) { break }
            }
            result := indices
            if iszero(mload(delimiter)) {
                result := add(indices, 0x20)
                mstore(result, sub(mload(indices), 2))
            }
        }
    }

    /// @dev Returns a concatenated string of `a` and `b`.
    /// Cheaper than `string.concat()` and does not de-align the free memory pointer.
    function concat(string memory a, string memory b)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let w := not(0x1f)
            result := mload(0x40)
            let aLength := mload(a)
            // Copy `a` one word at a time, backwards.
            for { let o := and(add(aLength, 0x20), w) } 1 {} {
                mstore(add(result, o), mload(add(a, o)))
                o := add(o, w) // `sub(o, 0x20)`.
                if iszero(o) { break }
            }
            let bLength := mload(b)
            let output := add(result, aLength)
            // Copy `b` one word at a time, backwards.
            for { let o := and(add(bLength, 0x20), w) } 1 {} {
                mstore(add(output, o), mload(add(b, o)))
                o := add(o, w) // `sub(o, 0x20)`.
                if iszero(o) { break }
            }
            let totalLength := add(aLength, bLength)
            let last := add(add(result, 0x20), totalLength)
            // Zeroize the slot after the string.
            mstore(last, 0)
            // Stores the length.
            mstore(result, totalLength)
            // Allocate memory for the length and the bytes,
            // rounded up to a multiple of 32.
            mstore(0x40, and(add(last, 0x1f), w))
        }
    }

    /// @dev Returns a copy of the string in either lowercase or UPPERCASE.
    /// WARNING! This function is only compatible with 7-bit ASCII strings.
    function toCase(string memory subject, bool toUpper)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let length := mload(subject)
            if length {
                result := add(mload(0x40), 0x20)
                subject := add(subject, 1)
                let flags := shl(add(70, shl(5, toUpper)), 0x3ffffff)
                let w := not(0)
                for { let o := length } 1 {} {
                    o := add(o, w)
                    let b := and(0xff, mload(add(subject, o)))
                    mstore8(add(result, o), xor(b, and(shr(b, flags), 0x20)))
                    if iszero(o) { break }
                }
                result := mload(0x40)
                mstore(result, length) // Store the length.
                let last := add(add(result, 0x20), length)
                mstore(last, 0) // Zeroize the slot after the string.
                mstore(0x40, add(last, 0x20)) // Allocate the memory.
            }
        }
    }

    /// @dev Returns a string from a small bytes32 string.
    /// `s` must be null-terminated, or behavior will be undefined.
    function fromSmallString(bytes32 s) internal pure returns (string memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            result := mload(0x40)
            let n := 0
            for {} byte(n, s) { n := add(n, 1) } {} // Scan for '\0'.
            mstore(result, n)
            let o := add(result, 0x20)
            mstore(o, s)
            mstore(add(o, n), 0)
            mstore(0x40, add(result, 0x40))
        }
    }

    /// @dev Returns the small string, with all bytes after the first null byte zeroized.
    function normalizeSmallString(bytes32 s) internal pure returns (bytes32 result) {
        /// @solidity memory-safe-assembly
        assembly {
            for {} byte(result, s) { result := add(result, 1) } {} // Scan for '\0'.
            mstore(0x00, s)
            mstore(result, 0x00)
            result := mload(0x00)
        }
    }

    /// @dev Returns the string as a normalized null-terminated small string.
    function toSmallString(string memory s) internal pure returns (bytes32 result) {
        /// @solidity memory-safe-assembly
        assembly {
            result := mload(s)
            if iszero(lt(result, 33)) {
                mstore(0x00, 0xec92f9a3) // `TooBigForSmallString()`.
                revert(0x1c, 0x04)
            }
            result := shl(shl(3, sub(32, result)), mload(add(s, result)))
        }
    }

    /// @dev Returns a lowercased copy of the string.
    /// WARNING! This function is only compatible with 7-bit ASCII strings.
    function lower(string memory subject) internal pure returns (string memory result) {
        result = toCase(subject, false);
    }

    /// @dev Returns an UPPERCASED copy of the string.
    /// WARNING! This function is only compatible with 7-bit ASCII strings.
    function upper(string memory subject) internal pure returns (string memory result) {
        result = toCase(subject, true);
    }

    /// @dev Escapes the string to be used within HTML tags.
    function escapeHTML(string memory s) internal pure returns (string memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            let end := add(s, mload(s))
            result := add(mload(0x40), 0x20)
            // Store the bytes of the packed offsets and strides into the scratch space.
            // `packed = (stride << 5) | offset`. Max offset is 20. Max stride is 6.
            mstore(0x1f, 0x900094)
            mstore(0x08, 0xc0000000a6ab)
            // Store "&quot;&amp;&#39;&lt;&gt;" into the scratch space.
            mstore(0x00, shl(64, 0x2671756f743b26616d703b262333393b266c743b2667743b))
            for {} iszero(eq(s, end)) {} {
                s := add(s, 1)
                let c := and(mload(s), 0xff)
                // Not in `["\"","'","&","<",">"]`.
                if iszero(and(shl(c, 1), 0x500000c400000000)) {
                    mstore8(result, c)
                    result := add(result, 1)
                    continue
                }
                let t := shr(248, mload(c))
                mstore(result, mload(and(t, 0x1f)))
                result := add(result, shr(5, t))
            }
            let last := result
            mstore(last, 0) // Zeroize the slot after the string.
            result := mload(0x40)
            mstore(result, sub(last, add(result, 0x20))) // Store the length.
            mstore(0x40, add(last, 0x20)) // Allocate the memory.
        }
    }

    /// @dev Escapes the string to be used within double-quotes in a JSON.
    /// If `addDoubleQuotes` is true, the result will be enclosed in double-quotes.
    function escapeJSON(string memory s, bool addDoubleQuotes)
        internal
        pure
        returns (string memory result)
    {
        /// @solidity memory-safe-assembly
        assembly {
            let end := add(s, mload(s))
            result := add(mload(0x40), 0x20)
            if addDoubleQuotes {
                mstore8(result, 34)
                result := add(1, result)
            }
            // Store "\\u0000" in scratch space.
            // Store "0123456789abcdef" in scratch space.
            // Also, store `{0x08:"b", 0x09:"t", 0x0a:"n", 0x0c:"f", 0x0d:"r"}`.
            // into the scratch space.
            mstore(0x15, 0x5c75303030303031323334353637383961626364656662746e006672)
            // Bitmask for detecting `["\"","\\"]`.
            let e := or(shl(0x22, 1), shl(0x5c, 1))
            for {} iszero(eq(s, end)) {} {
                s := add(s, 1)
                let c := and(mload(s), 0xff)
                if iszero(lt(c, 0x20)) {
                    if iszero(and(shl(c, 1), e)) {
                        // Not in `["\"","\\"]`.
                        mstore8(result, c)
                        result := add(result, 1)
                        continue
                    }
                    mstore8(result, 0x5c) // "\\".
                    mstore8(add(result, 1), c)
                    result := add(result, 2)
                    continue
                }
                if iszero(and(shl(c, 1), 0x3700)) {
                    // Not in `["\b","\t","\n","\f","\d"]`.
                    mstore8(0x1d, mload(shr(4, c))) // Hex value.
                    mstore8(0x1e, mload(and(c, 15))) // Hex value.
                    mstore(result, mload(0x19)) // "\\u00XX".
                    result := add(result, 6)
                    continue
                }
                mstore8(result, 0x5c) // "\\".
                mstore8(add(result, 1), mload(add(c, 8)))
                result := add(result, 2)
            }
            if addDoubleQuotes {
                mstore8(result, 34)
                result := add(1, result)
            }
            let last := result
            mstore(last, 0) // Zeroize the slot after the string.
            result := mload(0x40)
            mstore(result, sub(last, add(result, 0x20))) // Store the length.
            mstore(0x40, add(last, 0x20)) // Allocate the memory.
        }
    }

    /// @dev Escapes the string to be used within double-quotes in a JSON.
    function escapeJSON(string memory s) internal pure returns (string memory result) {
        result = escapeJSON(s, false);
    }

    /// @dev Returns whether `a` equals `b`.
    function eq(string memory a, string memory b) internal pure returns (bool result) {
        /// @solidity memory-safe-assembly
        assembly {
            result := eq(keccak256(add(a, 0x20), mload(a)), keccak256(add(b, 0x20), mload(b)))
        }
    }

    /// @dev Returns whether `a` equals `b`, where `b` is a null-terminated small string.
    function eqs(string memory a, bytes32 b) internal pure returns (bool result) {
        /// @solidity memory-safe-assembly
        assembly {
            // These should be evaluated on compile time, as far as possible.
            let m := not(shl(7, div(not(iszero(b)), 255))) // `0x7f7f ...`.
            let x := not(or(m, or(b, add(m, and(b, m)))))
            let r := shl(7, iszero(iszero(shr(128, x))))
            r := or(r, shl(6, iszero(iszero(shr(64, shr(r, x))))))
            r := or(r, shl(5, lt(0xffffffff, shr(r, x))))
            r := or(r, shl(4, lt(0xffff, shr(r, x))))
            r := or(r, shl(3, lt(0xff, shr(r, x))))
            // forgefmt: disable-next-item
            result := gt(eq(mload(a), add(iszero(x), xor(31, shr(3, r)))),
                xor(shr(add(8, r), b), shr(add(8, r), mload(add(a, 0x20)))))
        }
    }

    /// @dev Packs a single string with its length into a single word.
    /// Returns `bytes32(0)` if the length is zero or greater than 31.
    function packOne(string memory a) internal pure returns (bytes32 result) {
        /// @solidity memory-safe-assembly
        assembly {
            // We don't need to zero right pad the string,
            // since this is our own custom non-standard packing scheme.
            result :=
                mul(
                    // Load the length and the bytes.
                    mload(add(a, 0x1f)),
                    // `length != 0 && length < 32`. Abuses underflow.
                    // Assumes that the length is valid and within the block gas limit.
                    lt(sub(mload(a), 1), 0x1f)
                )
        }
    }

    /// @dev Unpacks a string packed using {packOne}.
    /// Returns the empty string if `packed` is `bytes32(0)`.
    /// If `packed` is not an output of {packOne}, the output behavior is undefined.
    function unpackOne(bytes32 packed) internal pure returns (string memory result) {
        /// @solidity memory-safe-assembly
        assembly {
            // Grab the free memory pointer.
            result := mload(0x40)
            // Allocate 2 words (1 for the length, 1 for the bytes).
            mstore(0x40, add(result, 0x40))
            // Zeroize the length slot.
            mstore(result, 0)
            // Store the length and bytes.
            mstore(add(result, 0x1f), packed)
            // Right pad with zeroes.
            mstore(add(add(result, 0x20), mload(result)), 0)
        }
    }

    /// @dev Packs two strings with their lengths into a single word.
    /// Returns `bytes32(0)` if combined length is zero or greater than 30.
    function packTwo(string memory a, string memory b) internal pure returns (bytes32 result) {
        /// @solidity memory-safe-assembly
        assembly {
            let aLength := mload(a)
            // We don't need to zero right pad the strings,
            // since this is our own custom non-standard packing scheme.
            result :=
                mul(
                    // Load the length and the bytes of `a` and `b`.
                    or(
                        shl(shl(3, sub(0x1f, aLength)), mload(add(a, aLength))),
                        mload(sub(add(b, 0x1e), aLength))
                    ),
                    // `totalLength != 0 && totalLength < 31`. Abuses underflow.
                    // Assumes that the lengths are valid and within the block gas limit.
                    lt(sub(add(aLength, mload(b)), 1), 0x1e)
                )
        }
    }

    /// @dev Unpacks strings packed using {packTwo}.
    /// Returns the empty strings if `packed` is `bytes32(0)`.
    /// If `packed` is not an output of {packTwo}, the output behavior is undefined.
    function unpackTwo(bytes32 packed)
        internal
        pure
        returns (string memory resultA, string memory resultB)
    {
        /// @solidity memory-safe-assembly
        assembly {
            // Grab the free memory pointer.
            resultA := mload(0x40)
            resultB := add(resultA, 0x40)
            // Allocate 2 words for each string (1 for the length, 1 for the byte). Total 4 words.
            mstore(0x40, add(resultB, 0x40))
            // Zeroize the length slots.
            mstore(resultA, 0)
            mstore(resultB, 0)
            // Store the lengths and bytes.
            mstore(add(resultA, 0x1f), packed)
            mstore(add(resultB, 0x1f), mload(add(add(resultA, 0x20), mload(resultA))))
            // Right pad with zeroes.
            mstore(add(add(resultA, 0x20), mload(resultA)), 0)
            mstore(add(add(resultB, 0x20), mload(resultB)), 0)
        }
    }

    /// @dev Directly returns `a` without copying.
    function directReturn(string memory a) internal pure {
        assembly {
            // Assumes that the string does not start from the scratch space.
            let retStart := sub(a, 0x20)
            let retSize := add(mload(a), 0x40)
            // Right pad with zeroes. Just in case the string is produced
            // by a method that doesn't zero right pad.
            mstore(add(retStart, retSize), 0)
            // Store the return offset.
            mstore(retStart, 0x20)
            // End the transaction, returning the string.
            return(retStart, retSize)
        }
    }
}