creation_sourcecode: // SPDX-License-Identifier: UNLICENSED
  pragma solidity 0.8.23;
  
  /**
   * @dev Interface of ERC721A.
   */
  interface IERC721A {
      /**
       * The caller must own the token or be an approved operator.
       */
      error ApprovalCallerNotOwnerNorApproved();
  
      /**
       * The token does not exist.
       */
      error ApprovalQueryForNonexistentToken();
  
      /**
       * Cannot query the balance for the zero address.
       */
      error BalanceQueryForZeroAddress();
  
      /**
       * Cannot mint to the zero address.
       */
      error MintToZeroAddress();
  
      /**
       * The quantity of tokens minted must be more than zero.
       */
      error MintZeroQuantity();
  
      /**
       * The token does not exist.
       */
      error OwnerQueryForNonexistentToken();
  
      /**
       * The caller must own the token or be an approved operator.
       */
      error TransferCallerNotOwnerNorApproved();
  
      /**
       * The token must be owned by `from`.
       */
      error TransferFromIncorrectOwner();
  
      /**
       * Cannot safely transfer to a contract that does not implement the
       * ERC721Receiver interface.
       */
      error TransferToNonERC721ReceiverImplementer();
  
      /**
       * Cannot transfer to the zero address.
       */
      error TransferToZeroAddress();
  
      /**
       * The token does not exist.
       */
      error URIQueryForNonexistentToken();
  
      /**
       * The `quantity` minted with ERC2309 exceeds the safety limit.
       */
      error MintERC2309QuantityExceedsLimit();
  
      /**
       * The `extraData` cannot be set on an unintialized ownership slot.
       */
      error OwnershipNotInitializedForExtraData();
  
      // =============================================================
      //                            STRUCTS
      // =============================================================
  
      struct TokenOwnership {
          // The address of the owner.
          address addr;
          // Stores the start time of ownership with minimal overhead for tokenomics.
          uint64 startTimestamp;
          // Whether the token has been burned.
          bool burned;
          // Arbitrary data similar to `startTimestamp` that can be set via {_extraData}.
          uint24 extraData;
      }
  
      // =============================================================
      //                         TOKEN COUNTERS
      // =============================================================
  
      /**
       * @dev Returns the total number of tokens in existence.
       * Burned tokens will reduce the count.
       * To get the total number of tokens minted, please see {_totalMinted}.
       */
      function totalSupply() external view returns (uint256);
  
      // =============================================================
      //                            IERC165
      // =============================================================
  
      /**
       * @dev Returns true if this contract implements the interface defined by
       * `interfaceId`. See the corresponding
       * [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)
       * to learn more about how these ids are created.
       *
       * This function call must use less than 30000 gas.
       */
      function supportsInterface(bytes4 interfaceId) external view returns (bool);
  
      // =============================================================
      //                            IERC721
      // =============================================================
  
      /**
       * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
       */
      event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
  
      /**
       * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
       */
      event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
  
      /**
       * @dev Emitted when `owner` enables or disables
       * (`approved`) `operator` to manage all of its assets.
       */
      event ApprovalForAll(address indexed owner, address indexed operator, bool approved);
  
      /**
       * @dev Returns the number of tokens in `owner`'s account.
       */
      function balanceOf(address owner) external view returns (uint256 balance);
  
      /**
       * @dev Returns the owner of the `tokenId` token.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       */
      function ownerOf(uint256 tokenId) external view returns (address owner);
  
      /**
       * @dev Safely transfers `tokenId` token from `from` to `to`,
       * checking first that contract recipients are aware of the ERC721 protocol
       * to prevent tokens from being forever locked.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `tokenId` token must exist and be owned by `from`.
       * - If the caller is not `from`, it must be have been allowed to move
       * this token by either {approve} or {setApprovalForAll}.
       * - 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 tokenId,
          bytes calldata data
      ) external payable;
  
      /**
       * @dev Equivalent to `safeTransferFrom(from, to, tokenId, '')`.
       */
      function safeTransferFrom(
          address from,
          address to,
          uint256 tokenId
      ) external payable;
  
      /**
       * @dev Transfers `tokenId` from `from` to `to`.
       *
       * WARNING: Usage of this method is discouraged, use {safeTransferFrom}
       * whenever possible.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `tokenId` token must be owned by `from`.
       * - If the caller is not `from`, it must be approved to move this token
       * by either {approve} or {setApprovalForAll}.
       *
       * Emits a {Transfer} event.
       */
      function transferFrom(
          address from,
          address to,
          uint256 tokenId
      ) external payable;
  
      /**
       * @dev Gives permission to `to` to transfer `tokenId` token to another account.
       * The approval is cleared when the token is transferred.
       *
       * Only a single account can be approved at a time, so approving the
       * zero address clears previous approvals.
       *
       * Requirements:
       *
       * - The caller must own the token or be an approved operator.
       * - `tokenId` must exist.
       *
       * Emits an {Approval} event.
       */
      function approve(address to, uint256 tokenId) external payable;
  
      /**
       * @dev Approve or remove `operator` as an operator for the caller.
       * Operators can call {transferFrom} or {safeTransferFrom}
       * for any token owned by the caller.
       *
       * Requirements:
       *
       * - The `operator` cannot be the caller.
       *
       * Emits an {ApprovalForAll} event.
       */
      function setApprovalForAll(address operator, bool _approved) external;
  
      /**
       * @dev Returns the account approved for `tokenId` token.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       */
      function getApproved(uint256 tokenId) external view returns (address operator);
  
      /**
       * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
       *
       * See {setApprovalForAll}.
       */
      function isApprovedForAll(address owner, address operator) external view returns (bool);
  
      // =============================================================
      //                        IERC721Metadata
      // =============================================================
  
      /**
       * @dev Returns the token collection name.
       */
      function name() external view returns (string memory);
  
      /**
       * @dev Returns the token collection symbol.
       */
      function symbol() external view returns (string memory);
  
      /**
       * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
       */
      function tokenURI(uint256 tokenId) external view returns (string memory);
  
      // =============================================================
      //                           IERC2309
      // =============================================================
  
      /**
       * @dev Emitted when tokens in `fromTokenId` to `toTokenId`
       * (inclusive) is transferred from `from` to `to`, as defined in the
       * [ERC2309](https://eips.ethereum.org/EIPS/eip-2309) standard.
       *
       * See {_mintERC2309} for more details.
       */
      event ConsecutiveTransfer(uint256 indexed fromTokenId, uint256 toTokenId, address indexed from, address indexed to);
  }
  
  /**
   * @dev Interface of ERC721AQueryable.
   */
  interface IERC721AQueryable is IERC721A {
      /**
       * Invalid query range (`start` >= `stop`).
       */
      error InvalidQueryRange();
  
      /**
       * @dev Returns the `TokenOwnership` struct at `tokenId` without reverting.
       *
       * If the `tokenId` is out of bounds:
       *
       * - `addr = address(0)`
       * - `startTimestamp = 0`
       * - `burned = false`
       * - `extraData = 0`
       *
       * If the `tokenId` is burned:
       *
       * - `addr = <Address of owner before token was burned>`
       * - `startTimestamp = <Timestamp when token was burned>`
       * - `burned = true`
       * - `extraData = <Extra data when token was burned>`
       *
       * Otherwise:
       *
       * - `addr = <Address of owner>`
       * - `startTimestamp = <Timestamp of start of ownership>`
       * - `burned = false`
       * - `extraData = <Extra data at start of ownership>`
       */
      function explicitOwnershipOf(uint256 tokenId) external view returns (TokenOwnership memory);
  
      /**
       * @dev Returns an array of `TokenOwnership` structs at `tokenIds` in order.
       * See {ERC721AQueryable-explicitOwnershipOf}
       */
      function explicitOwnershipsOf(uint256[] memory tokenIds) external view returns (TokenOwnership[] memory);
  
      /**
       * @dev Returns an array of token IDs owned by `owner`,
       * in the range [`start`, `stop`)
       * (i.e. `start <= tokenId < stop`).
       *
       * This function allows for tokens to be queried if the collection
       * grows too big for a single call of {ERC721AQueryable-tokensOfOwner}.
       *
       * Requirements:
       *
       * - `start < stop`
       */
      function tokensOfOwnerIn(
          address owner,
          uint256 start,
          uint256 stop
      ) external view returns (uint256[] memory);
  
      /**
       * @dev Returns an array of token IDs owned by `owner`.
       *
       * This function scans the ownership mapping and is O(`totalSupply`) in complexity.
       * It is meant to be called off-chain.
       *
       * See {ERC721AQueryable-tokensOfOwnerIn} for splitting the scan into
       * multiple smaller scans if the collection is large enough to cause
       * an out-of-gas error (10K collections should be fine).
       */
      function tokensOfOwner(address owner) external view returns (uint256[] memory);
  }
  
  /**
   * @dev Interface of ERC721 token receiver.
   */
  interface ERC721A__IERC721Receiver {
      function onERC721Received(
          address operator,
          address from,
          uint256 tokenId,
          bytes calldata data
      ) external returns (bytes4);
  }
  
  /**
   * @title ERC721A
   *
   * @dev Implementation of the [ERC721](https://eips.ethereum.org/EIPS/eip-721)
   * Non-Fungible Token Standard, including the Metadata extension.
   * Optimized for lower gas during batch mints.
   *
   * Token IDs are minted in sequential order (e.g. 0, 1, 2, 3, ...)
   * starting from `_startTokenId()`.
   *
   * Assumptions:
   *
   * - An owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
   * - The maximum token ID cannot exceed 2**256 - 1 (max value of uint256).
   */
  contract ERC721A is IERC721A {
      // Bypass for a `--via-ir` bug (https://github.com/chiru-labs/ERC721A/pull/364).
      struct TokenApprovalRef {
          address value;
      }
  
      // =============================================================
      //                           CONSTANTS
      // =============================================================
  
      // Mask of an entry in packed address data.
      uint256 private constant _BITMASK_ADDRESS_DATA_ENTRY = (1 << 64) - 1;
  
      // The bit position of `numberMinted` in packed address data.
      uint256 private constant _BITPOS_NUMBER_MINTED = 64;
  
      // The bit position of `numberBurned` in packed address data.
      uint256 private constant _BITPOS_NUMBER_BURNED = 128;
  
      // The bit position of `aux` in packed address data.
      uint256 private constant _BITPOS_AUX = 192;
  
      // Mask of all 256 bits in packed address data except the 64 bits for `aux`.
      uint256 private constant _BITMASK_AUX_COMPLEMENT = (1 << 192) - 1;
  
      // The bit position of `startTimestamp` in packed ownership.
      uint256 private constant _BITPOS_START_TIMESTAMP = 160;
  
      // The bit mask of the `burned` bit in packed ownership.
      uint256 private constant _BITMASK_BURNED = 1 << 224;
  
      // The bit position of the `nextInitialized` bit in packed ownership.
      uint256 private constant _BITPOS_NEXT_INITIALIZED = 225;
  
      // The bit mask of the `nextInitialized` bit in packed ownership.
      uint256 private constant _BITMASK_NEXT_INITIALIZED = 1 << 225;
  
      // The bit position of `extraData` in packed ownership.
      uint256 private constant _BITPOS_EXTRA_DATA = 232;
  
      // Mask of all 256 bits in a packed ownership except the 24 bits for `extraData`.
      uint256 private constant _BITMASK_EXTRA_DATA_COMPLEMENT = (1 << 232) - 1;
  
      // The mask of the lower 160 bits for addresses.
      uint256 private constant _BITMASK_ADDRESS = (1 << 160) - 1;
  
      // The maximum `quantity` that can be minted with {_mintERC2309}.
      // This limit is to prevent overflows on the address data entries.
      // For a limit of 5000, a total of 3.689e15 calls to {_mintERC2309}
      // is required to cause an overflow, which is unrealistic.
      uint256 private constant _MAX_MINT_ERC2309_QUANTITY_LIMIT = 5000;
  
      // The `Transfer` event signature is given by:
      // `keccak256(bytes("Transfer(address,address,uint256)"))`.
      bytes32 private constant _TRANSFER_EVENT_SIGNATURE =
          0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef;
  
      // =============================================================
      //                            STORAGE
      // =============================================================
  
      // The next token ID to be minted.
      uint256 private _currentIndex;
  
      // The number of tokens burned.
      uint256 private _burnCounter;
  
      // Token name
      string private _name;
  
      // Token symbol
      string private _symbol;
  
      // Mapping from token ID to ownership details
      // An empty struct value does not necessarily mean the token is unowned.
      // See {_packedOwnershipOf} implementation for details.
      //
      // Bits Layout:
      // - [0..159]   `addr`
      // - [160..223] `startTimestamp`
      // - [224]      `burned`
      // - [225]      `nextInitialized`
      // - [232..255] `extraData`
      mapping(uint256 => uint256) private _packedOwnerships;
  
      // Mapping owner address to address data.
      //
      // Bits Layout:
      // - [0..63]    `balance`
      // - [64..127]  `numberMinted`
      // - [128..191] `numberBurned`
      // - [192..255] `aux`
      mapping(address => uint256) private _packedAddressData;
  
      // Mapping from token ID to approved address.
      mapping(uint256 => TokenApprovalRef) private _tokenApprovals;
  
      // Mapping from owner to operator approvals
      mapping(address => mapping(address => bool)) private _operatorApprovals;
  
      // =============================================================
      //                          CONSTRUCTOR
      // =============================================================
  
      constructor(string memory name_, string memory symbol_) {
          _name = name_;
          _symbol = symbol_;
          _currentIndex = _startTokenId();
      }
  
      // =============================================================
      //                   TOKEN COUNTING OPERATIONS
      // =============================================================
  
      /**
       * @dev Returns the starting token ID.
       * To change the starting token ID, please override this function.
       */
      function _startTokenId() internal view virtual returns (uint256) {
          return 0;
      }
  
      /**
       * @dev Returns the next token ID to be minted.
       */
      function _nextTokenId() internal view virtual returns (uint256) {
          return _currentIndex;
      }
  
      /**
       * @dev Returns the total number of tokens in existence.
       * Burned tokens will reduce the count.
       * To get the total number of tokens minted, please see {_totalMinted}.
       */
      function totalSupply() public view virtual override returns (uint256) {
          // Counter underflow is impossible as _burnCounter cannot be incremented
          // more than `_currentIndex - _startTokenId()` times.
          unchecked {
              return _currentIndex - _burnCounter - _startTokenId();
          }
      }
  
      /**
       * @dev Returns the total amount of tokens minted in the contract.
       */
      function _totalMinted() internal view virtual returns (uint256) {
          // Counter underflow is impossible as `_currentIndex` does not decrement,
          // and it is initialized to `_startTokenId()`.
          unchecked {
              return _currentIndex - _startTokenId();
          }
      }
  
      /**
       * @dev Returns the total number of tokens burned.
       */
      function _totalBurned() internal view virtual returns (uint256) {
          return _burnCounter;
      }
  
      // =============================================================
      //                    ADDRESS DATA OPERATIONS
      // =============================================================
  
      /**
       * @dev Returns the number of tokens in `owner`'s account.
       */
      function balanceOf(address owner) public view virtual override returns (uint256) {
          if (owner == address(0)) revert BalanceQueryForZeroAddress();
          return _packedAddressData[owner] & _BITMASK_ADDRESS_DATA_ENTRY;
      }
  
      /**
       * Returns the number of tokens minted by `owner`.
       */
      function _numberMinted(address owner) internal view returns (uint256) {
          return (_packedAddressData[owner] >> _BITPOS_NUMBER_MINTED) & _BITMASK_ADDRESS_DATA_ENTRY;
      }
  
      /**
       * Returns the number of tokens burned by or on behalf of `owner`.
       */
      function _numberBurned(address owner) internal view returns (uint256) {
          return (_packedAddressData[owner] >> _BITPOS_NUMBER_BURNED) & _BITMASK_ADDRESS_DATA_ENTRY;
      }
  
      /**
       * Returns the auxiliary data for `owner`. (e.g. number of whitelist mint slots used).
       */
      function _getAux(address owner) internal view returns (uint64) {
          return uint64(_packedAddressData[owner] >> _BITPOS_AUX);
      }
  
      /**
       * Sets the auxiliary data for `owner`. (e.g. number of whitelist mint slots used).
       * If there are multiple variables, please pack them into a uint64.
       */
      function _setAux(address owner, uint64 aux) internal virtual {
          uint256 packed = _packedAddressData[owner];
          uint256 auxCasted;
          // Cast `aux` with assembly to avoid redundant masking.
          assembly {
              auxCasted := aux
          }
          packed = (packed & _BITMASK_AUX_COMPLEMENT) | (auxCasted << _BITPOS_AUX);
          _packedAddressData[owner] = packed;
      }
  
      // =============================================================
      //                            IERC165
      // =============================================================
  
      /**
       * @dev Returns true if this contract implements the interface defined by
       * `interfaceId`. See the corresponding
       * [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)
       * to learn more about how these ids are created.
       *
       * This function call must use less than 30000 gas.
       */
      function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
          // The interface IDs are constants representing the first 4 bytes
          // of the XOR of all function selectors in the interface.
          // See: [ERC165](https://eips.ethereum.org/EIPS/eip-165)
          // (e.g. `bytes4(i.functionA.selector ^ i.functionB.selector ^ ...)`)
          return
              interfaceId == 0x01ffc9a7 || // ERC165 interface ID for ERC165.
              interfaceId == 0x80ac58cd || // ERC165 interface ID for ERC721.
              interfaceId == 0x5b5e139f; // ERC165 interface ID for ERC721Metadata.
      }
  
      // =============================================================
      //                        IERC721Metadata
      // =============================================================
  
      /**
       * @dev Returns the token collection name.
       */
      function name() public view virtual override returns (string memory) {
          return _name;
      }
  
      /**
       * @dev Returns the token collection symbol.
       */
      function symbol() public view virtual override returns (string memory) {
          return _symbol;
      }
  
      /**
       * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
       */
      function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
          if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
  
          string memory baseURI = _baseURI();
          return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, _toString(tokenId))) : '';
      }
  
      /**
       * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
       * token will be the concatenation of the `baseURI` and the `tokenId`. Empty
       * by default, it can be overridden in child contracts.
       */
      function _baseURI() internal view virtual returns (string memory) {
          return '';
      }
  
      // =============================================================
      //                     OWNERSHIPS OPERATIONS
      // =============================================================
  
      /**
       * @dev Returns the owner of the `tokenId` token.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       */
      function ownerOf(uint256 tokenId) public view virtual override returns (address) {
          return address(uint160(_packedOwnershipOf(tokenId)));
      }
  
      /**
       * @dev Gas spent here starts off proportional to the maximum mint batch size.
       * It gradually moves to O(1) as tokens get transferred around over time.
       */
      function _ownershipOf(uint256 tokenId) internal view virtual returns (TokenOwnership memory) {
          return _unpackedOwnership(_packedOwnershipOf(tokenId));
      }
  
      /**
       * @dev Returns the unpacked `TokenOwnership` struct at `index`.
       */
      function _ownershipAt(uint256 index) internal view virtual returns (TokenOwnership memory) {
          return _unpackedOwnership(_packedOwnerships[index]);
      }
  
      /**
       * @dev Initializes the ownership slot minted at `index` for efficiency purposes.
       */
      function _initializeOwnershipAt(uint256 index) internal virtual {
          if (_packedOwnerships[index] == 0) {
              _packedOwnerships[index] = _packedOwnershipOf(index);
          }
      }
  
      /**
       * Returns the packed ownership data of `tokenId`.
       */
      function _packedOwnershipOf(uint256 tokenId) private view returns (uint256) {
          uint256 curr = tokenId;
  
          unchecked {
              if (_startTokenId() <= curr)
                  if (curr < _currentIndex) {
                      uint256 packed = _packedOwnerships[curr];
                      // If not burned.
                      if (packed & _BITMASK_BURNED == 0) {
                          // Invariant:
                          // There will always be an initialized ownership slot
                          // (i.e. `ownership.addr != address(0) && ownership.burned == false`)
                          // before an unintialized ownership slot
                          // (i.e. `ownership.addr == address(0) && ownership.burned == false`)
                          // Hence, `curr` will not underflow.
                          //
                          // We can directly compare the packed value.
                          // If the address is zero, packed will be zero.
                          while (packed == 0) {
                              packed = _packedOwnerships[--curr];
                          }
                          return packed;
                      }
                  }
          }
          revert OwnerQueryForNonexistentToken();
      }
  
      /**
       * @dev Returns the unpacked `TokenOwnership` struct from `packed`.
       */
      function _unpackedOwnership(uint256 packed) private pure returns (TokenOwnership memory ownership) {
          ownership.addr = address(uint160(packed));
          ownership.startTimestamp = uint64(packed >> _BITPOS_START_TIMESTAMP);
          ownership.burned = packed & _BITMASK_BURNED != 0;
          ownership.extraData = uint24(packed >> _BITPOS_EXTRA_DATA);
      }
  
      /**
       * @dev Packs ownership data into a single uint256.
       */
      function _packOwnershipData(address owner, uint256 flags) private view returns (uint256 result) {
          assembly {
              // Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean.
              owner := and(owner, _BITMASK_ADDRESS)
              // `owner | (block.timestamp << _BITPOS_START_TIMESTAMP) | flags`.
              result := or(owner, or(shl(_BITPOS_START_TIMESTAMP, timestamp()), flags))
          }
      }
  
      /**
       * @dev Returns the `nextInitialized` flag set if `quantity` equals 1.
       */
      function _nextInitializedFlag(uint256 quantity) private pure returns (uint256 result) {
          // For branchless setting of the `nextInitialized` flag.
          assembly {
              // `(quantity == 1) << _BITPOS_NEXT_INITIALIZED`.
              result := shl(_BITPOS_NEXT_INITIALIZED, eq(quantity, 1))
          }
      }
  
      // =============================================================
      //                      APPROVAL OPERATIONS
      // =============================================================
  
      /**
       * @dev Gives permission to `to` to transfer `tokenId` token to another account.
       * The approval is cleared when the token is transferred.
       *
       * Only a single account can be approved at a time, so approving the
       * zero address clears previous approvals.
       *
       * Requirements:
       *
       * - The caller must own the token or be an approved operator.
       * - `tokenId` must exist.
       *
       * Emits an {Approval} event.
       */
      function approve(address to, uint256 tokenId) public payable virtual override {
          address owner = ownerOf(tokenId);
  
          if (_msgSenderERC721A() != owner)
              if (!isApprovedForAll(owner, _msgSenderERC721A())) {
                  revert ApprovalCallerNotOwnerNorApproved();
              }
  
          _tokenApprovals[tokenId].value = to;
          emit Approval(owner, to, tokenId);
      }
  
      /**
       * @dev Returns the account approved for `tokenId` token.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       */
      function getApproved(uint256 tokenId) public view virtual override returns (address) {
          if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
  
          return _tokenApprovals[tokenId].value;
      }
  
      /**
       * @dev Approve or remove `operator` as an operator for the caller.
       * Operators can call {transferFrom} or {safeTransferFrom}
       * for any token owned by the caller.
       *
       * Requirements:
       *
       * - The `operator` cannot be the caller.
       *
       * Emits an {ApprovalForAll} event.
       */
      function setApprovalForAll(address operator, bool approved) public virtual override {
          _operatorApprovals[_msgSenderERC721A()][operator] = approved;
          emit ApprovalForAll(_msgSenderERC721A(), operator, approved);
      }
  
      /**
       * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
       *
       * See {setApprovalForAll}.
       */
      function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
          return _operatorApprovals[owner][operator];
      }
  
      /**
       * @dev Returns whether `tokenId` exists.
       *
       * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
       *
       * Tokens start existing when they are minted. See {_mint}.
       */
      function _exists(uint256 tokenId) internal view virtual returns (bool) {
          return
              _startTokenId() <= tokenId &&
              tokenId < _currentIndex && // If within bounds,
              _packedOwnerships[tokenId] & _BITMASK_BURNED == 0; // and not burned.
      }
  
      /**
       * @dev Returns whether `msgSender` is equal to `approvedAddress` or `owner`.
       */
      function _isSenderApprovedOrOwner(
          address approvedAddress,
          address owner,
          address msgSender
      ) private pure returns (bool result) {
          assembly {
              // Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean.
              owner := and(owner, _BITMASK_ADDRESS)
              // Mask `msgSender` to the lower 160 bits, in case the upper bits somehow aren't clean.
              msgSender := and(msgSender, _BITMASK_ADDRESS)
              // `msgSender == owner || msgSender == approvedAddress`.
              result := or(eq(msgSender, owner), eq(msgSender, approvedAddress))
          }
      }
  
      /**
       * @dev Returns the storage slot and value for the approved address of `tokenId`.
       */
      function _getApprovedSlotAndAddress(uint256 tokenId)
          private
          view
          returns (uint256 approvedAddressSlot, address approvedAddress)
      {
          TokenApprovalRef storage tokenApproval = _tokenApprovals[tokenId];
          // The following is equivalent to `approvedAddress = _tokenApprovals[tokenId].value`.
          assembly {
              approvedAddressSlot := tokenApproval.slot
              approvedAddress := sload(approvedAddressSlot)
          }
      }
  
      // =============================================================
      //                      TRANSFER OPERATIONS
      // =============================================================
  
      /**
       * @dev Transfers `tokenId` from `from` to `to`.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `tokenId` token must be owned by `from`.
       * - If the caller is not `from`, it must be approved to move this token
       * by either {approve} or {setApprovalForAll}.
       *
       * Emits a {Transfer} event.
       */
      function transferFrom(
          address from,
          address to,
          uint256 tokenId
      ) public payable virtual override {
          uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);
  
          if (address(uint160(prevOwnershipPacked)) != from) revert TransferFromIncorrectOwner();
  
          (uint256 approvedAddressSlot, address approvedAddress) = _getApprovedSlotAndAddress(tokenId);
  
          // The nested ifs save around 20+ gas over a compound boolean condition.
          if (!_isSenderApprovedOrOwner(approvedAddress, from, _msgSenderERC721A()))
              if (!isApprovedForAll(from, _msgSenderERC721A())) revert TransferCallerNotOwnerNorApproved();
  
          if (to == address(0)) revert TransferToZeroAddress();
  
          _beforeTokenTransfers(from, to, tokenId, 1);
  
          // Clear approvals from the previous owner.
          assembly {
              if approvedAddress {
                  // This is equivalent to `delete _tokenApprovals[tokenId]`.
                  sstore(approvedAddressSlot, 0)
              }
          }
  
          // Underflow of the sender's balance is impossible because we check for
          // ownership above and the recipient's balance can't realistically overflow.
          // Counter overflow is incredibly unrealistic as `tokenId` would have to be 2**256.
          unchecked {
              // We can directly increment and decrement the balances.
              --_packedAddressData[from]; // Updates: `balance -= 1`.
              ++_packedAddressData[to]; // Updates: `balance += 1`.
  
              // Updates:
              // - `address` to the next owner.
              // - `startTimestamp` to the timestamp of transfering.
              // - `burned` to `false`.
              // - `nextInitialized` to `true`.
              _packedOwnerships[tokenId] = _packOwnershipData(
                  to,
                  _BITMASK_NEXT_INITIALIZED | _nextExtraData(from, to, prevOwnershipPacked)
              );
  
              // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
              if (prevOwnershipPacked & _BITMASK_NEXT_INITIALIZED == 0) {
                  uint256 nextTokenId = tokenId + 1;
                  // If the next slot's address is zero and not burned (i.e. packed value is zero).
                  if (_packedOwnerships[nextTokenId] == 0) {
                      // If the next slot is within bounds.
                      if (nextTokenId != _currentIndex) {
                          // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
                          _packedOwnerships[nextTokenId] = prevOwnershipPacked;
                      }
                  }
              }
          }
  
          emit Transfer(from, to, tokenId);
          _afterTokenTransfers(from, to, tokenId, 1);
      }
  
      /**
       * @dev Equivalent to `safeTransferFrom(from, to, tokenId, '')`.
       */
      function safeTransferFrom(
          address from,
          address to,
          uint256 tokenId
      ) public payable virtual override {
          safeTransferFrom(from, to, tokenId, '');
      }
  
      /**
       * @dev Safely transfers `tokenId` token from `from` to `to`.
       *
       * Requirements:
       *
       * - `from` cannot be the zero address.
       * - `to` cannot be the zero address.
       * - `tokenId` token must exist and be owned by `from`.
       * - If the caller is not `from`, it must be approved to move this token
       * by either {approve} or {setApprovalForAll}.
       * - 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 tokenId,
          bytes memory _data
      ) public payable virtual override {
          transferFrom(from, to, tokenId);
          if (to.code.length != 0)
              if (!_checkContractOnERC721Received(from, to, tokenId, _data)) {
                  revert TransferToNonERC721ReceiverImplementer();
              }
      }
  
      /**
       * @dev Hook that is called before a set of serially-ordered token IDs
       * are about to be transferred. This includes minting.
       * And also called before burning one token.
       *
       * `startTokenId` - the first token ID to be transferred.
       * `quantity` - the amount to be transferred.
       *
       * Calling conditions:
       *
       * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
       * transferred to `to`.
       * - When `from` is zero, `tokenId` will be minted for `to`.
       * - When `to` is zero, `tokenId` will be burned by `from`.
       * - `from` and `to` are never both zero.
       */
      function _beforeTokenTransfers(
          address from,
          address to,
          uint256 startTokenId,
          uint256 quantity
      ) internal virtual {}
  
      /**
       * @dev Hook that is called after a set of serially-ordered token IDs
       * have been transferred. This includes minting.
       * And also called after one token has been burned.
       *
       * `startTokenId` - the first token ID to be transferred.
       * `quantity` - the amount to be transferred.
       *
       * Calling conditions:
       *
       * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
       * transferred to `to`.
       * - When `from` is zero, `tokenId` has been minted for `to`.
       * - When `to` is zero, `tokenId` has been burned by `from`.
       * - `from` and `to` are never both zero.
       */
      function _afterTokenTransfers(
          address from,
          address to,
          uint256 startTokenId,
          uint256 quantity
      ) internal virtual {}
  
      /**
       * @dev Private function to invoke {IERC721Receiver-onERC721Received} on a target contract.
       *
       * `from` - Previous owner of the given token ID.
       * `to` - Target address that will receive the token.
       * `tokenId` - Token ID to be transferred.
       * `_data` - Optional data to send along with the call.
       *
       * Returns whether the call correctly returned the expected magic value.
       */
      function _checkContractOnERC721Received(
          address from,
          address to,
          uint256 tokenId,
          bytes memory _data
      ) private returns (bool) {
          try ERC721A__IERC721Receiver(to).onERC721Received(_msgSenderERC721A(), from, tokenId, _data) returns (
              bytes4 retval
          ) {
              return retval == ERC721A__IERC721Receiver(to).onERC721Received.selector;
          } catch (bytes memory reason) {
              if (reason.length == 0) {
                  revert TransferToNonERC721ReceiverImplementer();
              } else {
                  assembly {
                      revert(add(32, reason), mload(reason))
                  }
              }
          }
      }
  
      // =============================================================
      //                        MINT OPERATIONS
      // =============================================================
  
      /**
       * @dev Mints `quantity` tokens and transfers them to `to`.
       *
       * Requirements:
       *
       * - `to` cannot be the zero address.
       * - `quantity` must be greater than 0.
       *
       * Emits a {Transfer} event for each mint.
       */
      function _mint(address to, uint256 quantity) internal virtual {
          uint256 startTokenId = _currentIndex;
          if (quantity == 0) revert MintZeroQuantity();
  
          _beforeTokenTransfers(address(0), to, startTokenId, quantity);
  
          // Overflows are incredibly unrealistic.
          // `balance` and `numberMinted` have a maximum limit of 2**64.
          // `tokenId` has a maximum limit of 2**256.
          unchecked {
              // Updates:
              // - `balance += quantity`.
              // - `numberMinted += quantity`.
              //
              // We can directly add to the `balance` and `numberMinted`.
              _packedAddressData[to] += quantity * ((1 << _BITPOS_NUMBER_MINTED) | 1);
  
              // Updates:
              // - `address` to the owner.
              // - `startTimestamp` to the timestamp of minting.
              // - `burned` to `false`.
              // - `nextInitialized` to `quantity == 1`.
              _packedOwnerships[startTokenId] = _packOwnershipData(
                  to,
                  _nextInitializedFlag(quantity) | _nextExtraData(address(0), to, 0)
              );
  
              uint256 toMasked;
              uint256 end = startTokenId + quantity;
  
              // Use assembly to loop and emit the `Transfer` event for gas savings.
              // The duplicated `log4` removes an extra check and reduces stack juggling.
              // The assembly, together with the surrounding Solidity code, have been
              // delicately arranged to nudge the compiler into producing optimized opcodes.
              assembly {
                  // Mask `to` to the lower 160 bits, in case the upper bits somehow aren't clean.
                  toMasked := and(to, _BITMASK_ADDRESS)
                  // Emit the `Transfer` event.
                  log4(
                      0, // Start of data (0, since no data).
                      0, // End of data (0, since no data).
                      _TRANSFER_EVENT_SIGNATURE, // Signature.
                      0, // `address(0)`.
                      toMasked, // `to`.
                      startTokenId // `tokenId`.
                  )
  
                  // The `iszero(eq(,))` check ensures that large values of `quantity`
                  // that overflows uint256 will make the loop run out of gas.
                  // The compiler will optimize the `iszero` away for performance.
                  for {
                      let tokenId := add(startTokenId, 1)
                  } iszero(eq(tokenId, end)) {
                      tokenId := add(tokenId, 1)
                  } {
                      // Emit the `Transfer` event. Similar to above.
                      log4(0, 0, _TRANSFER_EVENT_SIGNATURE, 0, toMasked, tokenId)
                  }
              }
              if (toMasked == 0) revert MintToZeroAddress();
  
              _currentIndex = end;
          }
          _afterTokenTransfers(address(0), to, startTokenId, quantity);
      }
  
      /**
       * @dev Mints `quantity` tokens and transfers them to `to`.
       *
       * This function is intended for efficient minting only during contract creation.
       *
       * It emits only one {ConsecutiveTransfer} as defined in
       * [ERC2309](https://eips.ethereum.org/EIPS/eip-2309),
       * instead of a sequence of {Transfer} event(s).
       *
       * Calling this function outside of contract creation WILL make your contract
       * non-compliant with the ERC721 standard.
       * For full ERC721 compliance, substituting ERC721 {Transfer} event(s) with the ERC2309
       * {ConsecutiveTransfer} event is only permissible during contract creation.
       *
       * Requirements:
       *
       * - `to` cannot be the zero address.
       * - `quantity` must be greater than 0.
       *
       * Emits a {ConsecutiveTransfer} event.
       */
      function _mintERC2309(address to, uint256 quantity) internal virtual {
          uint256 startTokenId = _currentIndex;
          if (to == address(0)) revert MintToZeroAddress();
          if (quantity == 0) revert MintZeroQuantity();
          if (quantity > _MAX_MINT_ERC2309_QUANTITY_LIMIT) revert MintERC2309QuantityExceedsLimit();
  
          _beforeTokenTransfers(address(0), to, startTokenId, quantity);
  
          // Overflows are unrealistic due to the above check for `quantity` to be below the limit.
          unchecked {
              // Updates:
              // - `balance += quantity`.
              // - `numberMinted += quantity`.
              //
              // We can directly add to the `balance` and `numberMinted`.
              _packedAddressData[to] += quantity * ((1 << _BITPOS_NUMBER_MINTED) | 1);
  
              // Updates:
              // - `address` to the owner.
              // - `startTimestamp` to the timestamp of minting.
              // - `burned` to `false`.
              // - `nextInitialized` to `quantity == 1`.
              _packedOwnerships[startTokenId] = _packOwnershipData(
                  to,
                  _nextInitializedFlag(quantity) | _nextExtraData(address(0), to, 0)
              );
  
              emit ConsecutiveTransfer(startTokenId, startTokenId + quantity - 1, address(0), to);
  
              _currentIndex = startTokenId + quantity;
          }
          _afterTokenTransfers(address(0), to, startTokenId, quantity);
      }
  
      /**
       * @dev Safely mints `quantity` tokens and transfers them to `to`.
       *
       * Requirements:
       *
       * - If `to` refers to a smart contract, it must implement
       * {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
       * - `quantity` must be greater than 0.
       *
       * See {_mint}.
       *
       * Emits a {Transfer} event for each mint.
       */
      function _safeMint(
          address to,
          uint256 quantity,
          bytes memory _data
      ) internal virtual {
          _mint(to, quantity);
  
          unchecked {
              if (to.code.length != 0) {
                  uint256 end = _currentIndex;
                  uint256 index = end - quantity;
                  do {
                      if (!_checkContractOnERC721Received(address(0), to, index++, _data)) {
                          revert TransferToNonERC721ReceiverImplementer();
                      }
                  } while (index < end);
                  // Reentrancy protection.
                  if (_currentIndex != end) revert();
              }
          }
      }
  
      /**
       * @dev Equivalent to `_safeMint(to, quantity, '')`.
       */
      function _safeMint(address to, uint256 quantity) internal virtual {
          _safeMint(to, quantity, '');
      }
  
      // =============================================================
      //                        BURN OPERATIONS
      // =============================================================
  
      /**
       * @dev Equivalent to `_burn(tokenId, false)`.
       */
      function _burn(uint256 tokenId) internal virtual {
          _burn(tokenId, false);
      }
  
      /**
       * @dev Destroys `tokenId`.
       * The approval is cleared when the token is burned.
       *
       * Requirements:
       *
       * - `tokenId` must exist.
       *
       * Emits a {Transfer} event.
       */
      function _burn(uint256 tokenId, bool approvalCheck) internal virtual {
          uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);
  
          address from = address(uint160(prevOwnershipPacked));
  
          (uint256 approvedAddressSlot, address approvedAddress) = _getApprovedSlotAndAddress(tokenId);
  
          if (approvalCheck) {
              // The nested ifs save around 20+ gas over a compound boolean condition.
              if (!_isSenderApprovedOrOwner(approvedAddress, from, _msgSenderERC721A()))
                  if (!isApprovedForAll(from, _msgSenderERC721A())) revert TransferCallerNotOwnerNorApproved();
          }
  
          _beforeTokenTransfers(from, address(0), tokenId, 1);
  
          // Clear approvals from the previous owner.
          assembly {
              if approvedAddress {
                  // This is equivalent to `delete _tokenApprovals[tokenId]`.
                  sstore(approvedAddressSlot, 0)
              }
          }
  
          // Underflow of the sender's balance is impossible because we check for
          // ownership above and the recipient's balance can't realistically overflow.
          // Counter overflow is incredibly unrealistic as `tokenId` would have to be 2**256.
          unchecked {
              // Updates:
              // - `balance -= 1`.
              // - `numberBurned += 1`.
              //
              // We can directly decrement the balance, and increment the number burned.
              // This is equivalent to `packed -= 1; packed += 1 << _BITPOS_NUMBER_BURNED;`.
              _packedAddressData[from] += (1 << _BITPOS_NUMBER_BURNED) - 1;
  
              // Updates:
              // - `address` to the last owner.
              // - `startTimestamp` to the timestamp of burning.
              // - `burned` to `true`.
              // - `nextInitialized` to `true`.
              _packedOwnerships[tokenId] = _packOwnershipData(
                  from,
                  (_BITMASK_BURNED | _BITMASK_NEXT_INITIALIZED) | _nextExtraData(from, address(0), prevOwnershipPacked)
              );
  
              // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
              if (prevOwnershipPacked & _BITMASK_NEXT_INITIALIZED == 0) {
                  uint256 nextTokenId = tokenId + 1;
                  // If the next slot's address is zero and not burned (i.e. packed value is zero).
                  if (_packedOwnerships[nextTokenId] == 0) {
                      // If the next slot is within bounds.
                      if (nextTokenId != _currentIndex) {
                          // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
                          _packedOwnerships[nextTokenId] = prevOwnershipPacked;
                      }
                  }
              }
          }
  
          emit Transfer(from, address(0), tokenId);
          _afterTokenTransfers(from, address(0), tokenId, 1);
  
          // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
          unchecked {
              _burnCounter++;
          }
      }
  
      // =============================================================
      //                     EXTRA DATA OPERATIONS
      // =============================================================
  
      /**
       * @dev Directly sets the extra data for the ownership data `index`.
       */
      function _setExtraDataAt(uint256 index, uint24 extraData) internal virtual {
          uint256 packed = _packedOwnerships[index];
          if (packed == 0) revert OwnershipNotInitializedForExtraData();
          uint256 extraDataCasted;
          // Cast `extraData` with assembly to avoid redundant masking.
          assembly {
              extraDataCasted := extraData
          }
          packed = (packed & _BITMASK_EXTRA_DATA_COMPLEMENT) | (extraDataCasted << _BITPOS_EXTRA_DATA);
          _packedOwnerships[index] = packed;
      }
  
      /**
       * @dev Called during each token transfer to set the 24bit `extraData` field.
       * Intended to be overridden by the cosumer contract.
       *
       * `previousExtraData` - the value of `extraData` before transfer.
       *
       * Calling conditions:
       *
       * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
       * transferred to `to`.
       * - When `from` is zero, `tokenId` will be minted for `to`.
       * - When `to` is zero, `tokenId` will be burned by `from`.
       * - `from` and `to` are never both zero.
       */
      function _extraData(
          address from,
          address to,
          uint24 previousExtraData
      ) internal view virtual returns (uint24) {}
  
      /**
       * @dev Returns the next extra data for the packed ownership data.
       * The returned result is shifted into position.
       */
      function _nextExtraData(
          address from,
          address to,
          uint256 prevOwnershipPacked
      ) private view returns (uint256) {
          uint24 extraData = uint24(prevOwnershipPacked >> _BITPOS_EXTRA_DATA);
          return uint256(_extraData(from, to, extraData)) << _BITPOS_EXTRA_DATA;
      }
  
      // =============================================================
      //                       OTHER OPERATIONS
      // =============================================================
  
      /**
       * @dev Returns the message sender (defaults to `msg.sender`).
       *
       * If you are writing GSN compatible contracts, you need to override this function.
       */
      function _msgSenderERC721A() internal view virtual returns (address) {
          return msg.sender;
      }
  
      /**
       * @dev Converts a uint256 to its ASCII string decimal representation.
       */
      function _toString(uint256 value) internal pure virtual returns (string memory str) {
          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. Total: 5 * 0x20 = 0xa0.
              let m := add(mload(0x40), 0xa0)
              // Update the free memory pointer to allocate.
              mstore(0x40, m)
              // Assign the `str` to the end.
              str := sub(m, 0x20)
              // Zeroize the slot after the string.
              mstore(str, 0)
  
              // Cache the end of the memory to calculate the length later.
              let end := str
  
              // We write the string from rightmost digit to leftmost digit.
              // The following is essentially a do-while loop that also handles the zero case.
              // prettier-ignore
              for { let temp := value } 1 {} {
                  str := 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)
                  // prettier-ignore
                  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)
          }
      }
  }
  
  /**
   * @title ERC721AQueryable.
   *
   * @dev ERC721A subclass with convenience query functions.
   */
  abstract contract ERC721AQueryable is ERC721A, IERC721AQueryable {
      /**
       * @dev Returns the `TokenOwnership` struct at `tokenId` without reverting.
       *
       * If the `tokenId` is out of bounds:
       *
       * - `addr = address(0)`
       * - `startTimestamp = 0`
       * - `burned = false`
       * - `extraData = 0`
       *
       * If the `tokenId` is burned:
       *
       * - `addr = <Address of owner before token was burned>`
       * - `startTimestamp = <Timestamp when token was burned>`
       * - `burned = true`
       * - `extraData = <Extra data when token was burned>`
       *
       * Otherwise:
       *
       * - `addr = <Address of owner>`
       * - `startTimestamp = <Timestamp of start of ownership>`
       * - `burned = false`
       * - `extraData = <Extra data at start of ownership>`
       */
      function explicitOwnershipOf(uint256 tokenId) public view virtual override returns (TokenOwnership memory) {
          TokenOwnership memory ownership;
          if (tokenId < _startTokenId() || tokenId >= _nextTokenId()) {
              return ownership;
          }
          ownership = _ownershipAt(tokenId);
          if (ownership.burned) {
              return ownership;
          }
          return _ownershipOf(tokenId);
      }
  
      /**
       * @dev Returns an array of `TokenOwnership` structs at `tokenIds` in order.
       * See {ERC721AQueryable-explicitOwnershipOf}
       */
      function explicitOwnershipsOf(uint256[] calldata tokenIds)
          external
          view
          virtual
          override
          returns (TokenOwnership[] memory)
      {
          unchecked {
              uint256 tokenIdsLength = tokenIds.length;
              TokenOwnership[] memory ownerships = new TokenOwnership[](tokenIdsLength);
              for (uint256 i; i != tokenIdsLength; ++i) {
                  ownerships[i] = explicitOwnershipOf(tokenIds[i]);
              }
              return ownerships;
          }
      }
  
      /**
       * @dev Returns an array of token IDs owned by `owner`,
       * in the range [`start`, `stop`)
       * (i.e. `start <= tokenId < stop`).
       *
       * This function allows for tokens to be queried if the collection
       * grows too big for a single call of {ERC721AQueryable-tokensOfOwner}.
       *
       * Requirements:
       *
       * - `start < stop`
       */
      function tokensOfOwnerIn(
          address owner,
          uint256 start,
          uint256 stop
      ) external view virtual override returns (uint256[] memory) {
          unchecked {
              if (start >= stop) revert InvalidQueryRange();
              uint256 tokenIdsIdx;
              uint256 stopLimit = _nextTokenId();
              // Set `start = max(start, _startTokenId())`.
              if (start < _startTokenId()) {
                  start = _startTokenId();
              }
              // Set `stop = min(stop, stopLimit)`.
              if (stop > stopLimit) {
                  stop = stopLimit;
              }
              uint256 tokenIdsMaxLength = balanceOf(owner);
              // Set `tokenIdsMaxLength = min(balanceOf(owner), stop - start)`,
              // to cater for cases where `balanceOf(owner)` is too big.
              if (start < stop) {
                  uint256 rangeLength = stop - start;
                  if (rangeLength < tokenIdsMaxLength) {
                      tokenIdsMaxLength = rangeLength;
                  }
              } else {
                  tokenIdsMaxLength = 0;
              }
              uint256[] memory tokenIds = new uint256[](tokenIdsMaxLength);
              if (tokenIdsMaxLength == 0) {
                  return tokenIds;
              }
              // We need to call `explicitOwnershipOf(start)`,
              // because the slot at `start` may not be initialized.
              TokenOwnership memory ownership = explicitOwnershipOf(start);
              address currOwnershipAddr;
              // If the starting slot exists (i.e. not burned), initialize `currOwnershipAddr`.
              // `ownership.address` will not be zero, as `start` is clamped to the valid token ID range.
              if (!ownership.burned) {
                  currOwnershipAddr = ownership.addr;
              }
              for (uint256 i = start; i != stop && tokenIdsIdx != tokenIdsMaxLength; ++i) {
                  ownership = _ownershipAt(i);
                  if (ownership.burned) {
                      continue;
                  }
                  if (ownership.addr != address(0)) {
                      currOwnershipAddr = ownership.addr;
                  }
                  if (currOwnershipAddr == owner) {
                      tokenIds[tokenIdsIdx++] = i;
                  }
              }
              // Downsize the array to fit.
              assembly {
                  mstore(tokenIds, tokenIdsIdx)
              }
              return tokenIds;
          }
      }
  
      /**
       * @dev Returns an array of token IDs owned by `owner`.
       *
       * This function scans the ownership mapping and is O(`totalSupply`) in complexity.
       * It is meant to be called off-chain.
       *
       * See {ERC721AQueryable-tokensOfOwnerIn} for splitting the scan into
       * multiple smaller scans if the collection is large enough to cause
       * an out-of-gas error (10K collections should be fine).
       */
      function tokensOfOwner(address owner) external view virtual override returns (uint256[] memory) {
          unchecked {
              uint256 tokenIdsIdx;
              address currOwnershipAddr;
              uint256 tokenIdsLength = balanceOf(owner);
              uint256[] memory tokenIds = new uint256[](tokenIdsLength);
              TokenOwnership memory ownership;
              for (uint256 i = _startTokenId(); tokenIdsIdx != tokenIdsLength; ++i) {
                  ownership = _ownershipAt(i);
                  if (ownership.burned) {
                      continue;
                  }
                  if (ownership.addr != address(0)) {
                      currOwnershipAddr = ownership.addr;
                  }
                  if (currOwnershipAddr == owner) {
                      tokenIds[tokenIdsIdx++] = i;
                  }
              }
              return tokenIds;
          }
      }
  }
  
  /**
   * @dev Provides information about the current execution context, including the
   * sender of the transaction and its data. While these are generally available
   * via msg.sender and msg.data, they should not be accessed in such a direct
   * manner, since when dealing with meta-transactions the account sending and
   * paying for execution may not be the actual sender (as far as an application
   * is concerned).
   *
   * This contract is only required for intermediate, library-like contracts.
   */
  abstract contract Context {
      function _msgSender() internal view virtual returns (address) {
          return msg.sender;
      }
  
      function _msgData() internal view virtual returns (bytes calldata) {
          return msg.data;
      }
  
      function _contextSuffixLength() internal view virtual returns (uint256) {
          return 0;
      }
  }
  
  /**
   * @dev Contract module which provides a basic access control mechanism, where
   * there is an account (an owner) that can be granted exclusive access to
   * specific functions.
   *
   * The initial owner is set to the address provided by the deployer. This can
   * later be changed with {transferOwnership}.
   *
   * This module is used through inheritance. It will make available the modifier
   * `onlyOwner`, which can be applied to your functions to restrict their use to
   * the owner.
   */
  abstract contract Ownable is Context {
      address private _owner;
  
      /**
       * @dev The caller account is not authorized to perform an operation.
       */
      error OwnableUnauthorizedAccount(address account);
  
      /**
       * @dev The owner is not a valid owner account. (eg. `address(0)`)
       */
      error OwnableInvalidOwner(address owner);
  
      event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
  
      /**
       * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
       */
      constructor(address initialOwner) {
          if (initialOwner == address(0)) {
              revert OwnableInvalidOwner(address(0));
          }
          _transferOwnership(initialOwner);
      }
  
      /**
       * @dev Throws if called by any account other than the owner.
       */
      modifier onlyOwner() {
          _checkOwner();
          _;
      }
  
      /**
       * @dev Returns the address of the current owner.
       */
      function owner() public view virtual returns (address) {
          return _owner;
      }
  
      /**
       * @dev Throws if the sender is not the owner.
       */
      function _checkOwner() internal view virtual {
          if (owner() != _msgSender()) {
              revert OwnableUnauthorizedAccount(_msgSender());
          }
      }
  
      /**
       * @dev Leaves the contract without owner. It will not be possible to call
       * `onlyOwner` functions. Can only be called by the current owner.
       *
       * NOTE: Renouncing ownership will leave the contract without an owner,
       * thereby disabling any functionality that is only available to the owner.
       */
      function renounceOwnership() public virtual onlyOwner {
          _transferOwnership(address(0));
      }
  
      /**
       * @dev Transfers ownership of the contract to a new account (`newOwner`).
       * Can only be called by the current owner.
       */
      function transferOwnership(address newOwner) public virtual onlyOwner {
          if (newOwner == address(0)) {
              revert OwnableInvalidOwner(address(0));
          }
          _transferOwnership(newOwner);
      }
  
      /**
       * @dev Transfers ownership of the contract to a new account (`newOwner`).
       * Internal function without access restriction.
       */
      function _transferOwnership(address newOwner) internal virtual {
          address oldOwner = _owner;
          _owner = newOwner;
          emit OwnershipTransferred(oldOwner, newOwner);
      }
  }
  
  /**
   * @dev Contract module which provides access control mechanism, where
   * there is an account (an owner) that can be granted exclusive access to
   * specific functions.
   *
   * The initial owner is specified at deployment time in the constructor for `Ownable`. This
   * can later be changed with {transferOwnership} and {acceptOwnership}.
   *
   * This module is used through inheritance. It will make available all functions
   * from parent (Ownable).
   */
  abstract contract Ownable2Step is Ownable {
      address private _pendingOwner;
  
      event OwnershipTransferStarted(address indexed previousOwner, address indexed newOwner);
  
      /**
       * @dev Returns the address of the pending owner.
       */
      function pendingOwner() public view virtual returns (address) {
          return _pendingOwner;
      }
  
      /**
       * @dev Starts the ownership transfer of the contract to a new account. Replaces the pending transfer if there is one.
       * Can only be called by the current owner.
       */
      function transferOwnership(address newOwner) public virtual override onlyOwner {
          _pendingOwner = newOwner;
          emit OwnershipTransferStarted(owner(), newOwner);
      }
  
      /**
       * @dev Transfers ownership of the contract to a new account (`newOwner`) and deletes any pending owner.
       * Internal function without access restriction.
       */
      function _transferOwnership(address newOwner) internal virtual override {
          delete _pendingOwner;
          super._transferOwnership(newOwner);
      }
  
      /**
       * @dev The new owner accepts the ownership transfer.
       */
      function acceptOwnership() public virtual {
          address sender = _msgSender();
          if (pendingOwner() != sender) {
              revert OwnableUnauthorizedAccount(sender);
          }
          _transferOwnership(sender);
      }
  }
  
  event ReplaceImplementationStarted(address indexed previousImplementation, address indexed newImplementation);
  event ReplaceImplementation(address indexed previousImplementation, address indexed newImplementation);
  error Unauthorized();
  
  contract Upgradeable2Step is Ownable2Step {
      address public pendingImplementation;
      address public implementation;
  
      constructor() Ownable(msg.sender) {}
  
      // called on an inheriting proxy contract
      function replaceImplementation(address impl_) public onlyOwner {
          pendingImplementation = impl_;
          emit ReplaceImplementationStarted(implementation, impl_);
      }
  
      // called from an inheriting implementation contract
      function acceptImplementation() public {
          if (msg.sender != pendingImplementation) {
              revert OwnableUnauthorizedAccount(msg.sender);
          }
          emit ReplaceImplementation(implementation, msg.sender);
          delete pendingImplementation;
          implementation = msg.sender;
      }
  
      // called on an inheriting implementation contract
      function becomeImplementation(Upgradeable2Step proxy) public {
          if (msg.sender != proxy.owner()) {
              revert Unauthorized();
          }
          proxy.acceptImplementation();
      }
  }
  
  contract Proxy2Step is Upgradeable2Step {
  
      constructor(address impl_) {
          implementation = impl_;
      }
  
      fallback() external payable {
          assembly {
              calldatacopy(0, 0, calldatasize())
              let result := delegatecall(gas(), sload(implementation.slot), 0, calldatasize(), 0, 0)
              returndatacopy(0, 0, returndatasize())
              switch result
              case 0 { revert(0, returndatasize()) }
              default { return(0, returndatasize()) }
          }
      }
  }
  
  error NotOwned(uint256 nftId);
  
  contract FungifyNFT is Upgradeable2Step, ERC721A, ERC721AQueryable {
  
      // --- Auth ---
      mapping (address => uint) public wards;
      function rely(address guy) external onlyOwner { wards[guy] = 1; }
      function deny(address guy) external onlyOwner { wards[guy] = 0; }
      modifier auth {
          if (wards[msg.sender] != 1) {
              revert Unauthorized();
          }
          _;
      }
  
      string public baseURI;
  
      constructor() ERC721A(name(), symbol()) {}
  
      function supportsInterface(bytes4 interfaceId) public view override(ERC721A, IERC721A) returns (bool) {
          return super.supportsInterface(interfaceId);
      }
  
      function mint(address receiver, uint256 quantity) external auth {
          _safeMint(receiver, quantity);
      }
  
      function burn(uint[] calldata nftIds, address user) external auth {
          for(uint i; i < nftIds.length;) {
              if (ownerOf(nftIds[i]) != user) {
                  revert NotOwned(nftIds[i]);
              }
              _burn(nftIds[i]);
              unchecked { i++; }
          }
      }
  
      function name() public view override(ERC721A, IERC721A) returns (string memory) {
          return "Fungify NFT";
      }
  
      function symbol() public view override(ERC721A, IERC721A) returns (string memory) {
          return "FUNGNFT";
      }
  
      function tokenURI(uint256 tokenId) public view override(ERC721A, IERC721A) returns (string memory) {
          if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
  
          string memory baseURI_ = baseURI;
          return bytes(baseURI_).length != 0 ? string(abi.encodePacked(baseURI_, _toString(tokenId))) : '';
      }
  
      function setBaseURI(string calldata baseURI_) external onlyOwner {
          baseURI = baseURI_;
      }
  }