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// SPDX-License-Identifier: MIT |
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// ERC721A Contracts v4.3.0 |
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// Creator: Chiru Labs |
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pragma solidity ^0.8.4; |
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import './IERC721A.sol'; |
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/** |
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* @dev Interface of ERC721 token receiver. |
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*/ |
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interface ERC721A__IERC721Receiver { |
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function onERC721Received( |
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address operator, |
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address from, |
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uint256 tokenId, |
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bytes calldata data |
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) external returns (bytes4); |
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} |
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/** |
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* @title ERC721A |
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* |
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* @dev Implementation of the [ERC721](https://eips.ethereum.org/EIPS/eip-721) |
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* Non-Fungible Token Standard, including the Metadata extension. |
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* Optimized for lower gas during batch mints. |
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* |
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* Token IDs are minted in sequential order (e.g. 0, 1, 2, 3, ...) |
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* starting from `_startTokenId()`. |
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* |
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* The `_sequentialUpTo()` function can be overriden to enable spot mints |
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* (i.e. non-consecutive mints) for `tokenId`s greater than `_sequentialUpTo()`. |
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* |
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* Assumptions: |
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* |
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* - An owner cannot have more than 2**64 - 1 (max value of uint64) of supply. |
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* - The maximum token ID cannot exceed 2**256 - 1 (max value of uint256). |
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*/ |
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contract ERC721A is IERC721A { |
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// Bypass for a `--via-ir` bug (https://github.com/chiru-labs/ERC721A/pull/364). |
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struct TokenApprovalRef { |
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address value; |
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} |
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// ============================================================= |
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// CONSTANTS |
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// ============================================================= |
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// Mask of an entry in packed address data. |
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uint256 private constant _BITMASK_ADDRESS_DATA_ENTRY = (1 << 64) - 1; |
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// The bit position of `numberMinted` in packed address data. |
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uint256 private constant _BITPOS_NUMBER_MINTED = 64; |
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// The bit position of `numberBurned` in packed address data. |
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uint256 private constant _BITPOS_NUMBER_BURNED = 128; |
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// The bit position of `aux` in packed address data. |
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uint256 private constant _BITPOS_AUX = 192; |
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// Mask of all 256 bits in packed address data except the 64 bits for `aux`. |
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uint256 private constant _BITMASK_AUX_COMPLEMENT = (1 << 192) - 1; |
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// The bit position of `startTimestamp` in packed ownership. |
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uint256 private constant _BITPOS_START_TIMESTAMP = 160; |
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// The bit mask of the `burned` bit in packed ownership. |
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uint256 private constant _BITMASK_BURNED = 1 << 224; |
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// The bit position of the `nextInitialized` bit in packed ownership. |
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uint256 private constant _BITPOS_NEXT_INITIALIZED = 225; |
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// The bit mask of the `nextInitialized` bit in packed ownership. |
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uint256 private constant _BITMASK_NEXT_INITIALIZED = 1 << 225; |
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// The bit position of `extraData` in packed ownership. |
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uint256 private constant _BITPOS_EXTRA_DATA = 232; |
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// Mask of all 256 bits in a packed ownership except the 24 bits for `extraData`. |
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uint256 private constant _BITMASK_EXTRA_DATA_COMPLEMENT = (1 << 232) - 1; |
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// The mask of the lower 160 bits for addresses. |
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uint256 private constant _BITMASK_ADDRESS = (1 << 160) - 1; |
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// The maximum `quantity` that can be minted with {_mintERC2309}. |
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// This limit is to prevent overflows on the address data entries. |
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// For a limit of 5000, a total of 3.689e15 calls to {_mintERC2309} |
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// is required to cause an overflow, which is unrealistic. |
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uint256 private constant _MAX_MINT_ERC2309_QUANTITY_LIMIT = 5000; |
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// The `Transfer` event signature is given by: |
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// `keccak256(bytes("Transfer(address,address,uint256)"))`. |
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bytes32 private constant _TRANSFER_EVENT_SIGNATURE = |
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0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef; |
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// ============================================================= |
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// STORAGE |
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// ============================================================= |
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// The next token ID to be minted. |
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uint256 private _currentIndex; |
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// The number of tokens burned. |
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uint256 private _burnCounter; |
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// Token name |
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string private _name; |
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// Token symbol |
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string private _symbol; |
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// Mapping from token ID to ownership details |
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// An empty struct value does not necessarily mean the token is unowned. |
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// See {_packedOwnershipOf} implementation for details. |
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// |
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// Bits Layout: |
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// - [0..159] `addr` |
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// - [160..223] `startTimestamp` |
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// - [224] `burned` |
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// - [225] `nextInitialized` |
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// - [232..255] `extraData` |
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mapping(uint256 => uint256) private _packedOwnerships; |
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// Mapping owner address to address data. |
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// |
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// Bits Layout: |
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// - [0..63] `balance` |
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// - [64..127] `numberMinted` |
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// - [128..191] `numberBurned` |
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// - [192..255] `aux` |
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mapping(address => uint256) private _packedAddressData; |
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// Mapping from token ID to approved address. |
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mapping(uint256 => TokenApprovalRef) private _tokenApprovals; |
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// Mapping from owner to operator approvals |
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mapping(address => mapping(address => bool)) private _operatorApprovals; |
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// The amount of tokens minted above `_sequentialUpTo()`. |
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// We call these spot mints (i.e. non-sequential mints). |
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uint256 private _spotMinted; |
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// ============================================================= |
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// CONSTRUCTOR |
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// ============================================================= |
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constructor(string memory name_, string memory symbol_) { |
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_name = name_; |
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_symbol = symbol_; |
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_currentIndex = _startTokenId(); |
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if (_sequentialUpTo() < _startTokenId()) _revert(SequentialUpToTooSmall.selector); |
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} |
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// ============================================================= |
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// TOKEN COUNTING OPERATIONS |
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// ============================================================= |
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/** |
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* @dev Returns the starting token ID for sequential mints. |
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* |
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* Override this function to change the starting token ID for sequential mints. |
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* |
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* Note: The value returned must never change after any tokens have been minted. |
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*/ |
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function _startTokenId() internal view virtual returns (uint256) { |
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return 0; |
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} |
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/** |
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* @dev Returns the maximum token ID (inclusive) for sequential mints. |
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* |
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* Override this function to return a value less than 2**256 - 1, |
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* but greater than `_startTokenId()`, to enable spot (non-sequential) mints. |
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* |
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* Note: The value returned must never change after any tokens have been minted. |
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*/ |
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function _sequentialUpTo() internal view virtual returns (uint256) { |
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return type(uint256).max; |
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} |
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/** |
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* @dev Returns the next token ID to be minted. |
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*/ |
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function _nextTokenId() internal view virtual returns (uint256) { |
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return _currentIndex; |
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} |
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/** |
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* @dev Returns the total number of tokens in existence. |
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* Burned tokens will reduce the count. |
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* To get the total number of tokens minted, please see {_totalMinted}. |
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*/ |
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function totalSupply() public view virtual override returns (uint256 result) { |
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// Counter underflow is impossible as `_burnCounter` cannot be incremented |
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// more than `_currentIndex + _spotMinted - _startTokenId()` times. |
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unchecked { |
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// With spot minting, the intermediate `result` can be temporarily negative, |
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// and the computation must be unchecked. |
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result = _currentIndex - _burnCounter - _startTokenId(); |
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if (_sequentialUpTo() != type(uint256).max) result += _spotMinted; |
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} |
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} |
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/** |
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* @dev Returns the total amount of tokens minted in the contract. |
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*/ |
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function _totalMinted() internal view virtual returns (uint256 result) { |
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// Counter underflow is impossible as `_currentIndex` does not decrement, |
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// and it is initialized to `_startTokenId()`. |
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unchecked { |
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result = _currentIndex - _startTokenId(); |
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if (_sequentialUpTo() != type(uint256).max) result += _spotMinted; |
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} |
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} |
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/** |
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* @dev Returns the total number of tokens burned. |
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*/ |
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function _totalBurned() internal view virtual returns (uint256) { |
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return _burnCounter; |
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} |
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/** |
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* @dev Returns the total number of tokens that are spot-minted. |
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*/ |
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function _totalSpotMinted() internal view virtual returns (uint256) { |
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return _spotMinted; |
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} |
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// ============================================================= |
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// ADDRESS DATA OPERATIONS |
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// ============================================================= |
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/** |
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* @dev Returns the number of tokens in `owner`'s account. |
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*/ |
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function balanceOf(address owner) public view virtual override returns (uint256) { |
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if (owner == address(0)) _revert(BalanceQueryForZeroAddress.selector); |
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return _packedAddressData[owner] & _BITMASK_ADDRESS_DATA_ENTRY; |
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} |
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/** |
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* Returns the number of tokens minted by `owner`. |
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*/ |
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function _numberMinted(address owner) internal view returns (uint256) { |
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return (_packedAddressData[owner] >> _BITPOS_NUMBER_MINTED) & _BITMASK_ADDRESS_DATA_ENTRY; |
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} |
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/** |
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* Returns the number of tokens burned by or on behalf of `owner`. |
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*/ |
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function _numberBurned(address owner) internal view returns (uint256) { |
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return (_packedAddressData[owner] >> _BITPOS_NUMBER_BURNED) & _BITMASK_ADDRESS_DATA_ENTRY; |
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} |
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/** |
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* Returns the auxiliary data for `owner`. (e.g. number of whitelist mint slots used). |
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*/ |
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function _getAux(address owner) internal view returns (uint64) { |
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return uint64(_packedAddressData[owner] >> _BITPOS_AUX); |
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} |
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/** |
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* Sets the auxiliary data for `owner`. (e.g. number of whitelist mint slots used). |
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* If there are multiple variables, please pack them into a uint64. |
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*/ |
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function _setAux(address owner, uint64 aux) internal virtual { |
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uint256 packed = _packedAddressData[owner]; |
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uint256 auxCasted; |
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// Cast `aux` with assembly to avoid redundant masking. |
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assembly { |
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auxCasted := aux |
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} |
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packed = (packed & _BITMASK_AUX_COMPLEMENT) | (auxCasted << _BITPOS_AUX); |
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_packedAddressData[owner] = packed; |
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} |
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// ============================================================= |
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// IERC165 |
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// ============================================================= |
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/** |
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* @dev Returns true if this contract implements the interface defined by |
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* `interfaceId`. See the corresponding |
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* [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified) |
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* to learn more about how these ids are created. |
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* |
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* This function call must use less than 30000 gas. |
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*/ |
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function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) { |
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// The interface IDs are constants representing the first 4 bytes |
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// of the XOR of all function selectors in the interface. |
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// See: [ERC165](https://eips.ethereum.org/EIPS/eip-165) |
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// (e.g. `bytes4(i.functionA.selector ^ i.functionB.selector ^ ...)`) |
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return |
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interfaceId == 0x01ffc9a7 || // ERC165 interface ID for ERC165. |
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interfaceId == 0x80ac58cd || // ERC165 interface ID for ERC721. |
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interfaceId == 0x5b5e139f; // ERC165 interface ID for ERC721Metadata. |
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} |
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// ============================================================= |
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// IERC721Metadata |
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// ============================================================= |
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/** |
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* @dev Returns the token collection name. |
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*/ |
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function name() public view virtual override returns (string memory) { |
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return _name; |
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} |
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/** |
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* @dev Returns the token collection symbol. |
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*/ |
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function symbol() public view virtual override returns (string memory) { |
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return _symbol; |
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} |
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/** |
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* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token. |
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*/ |
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function tokenURI(uint256 tokenId) public view virtual override returns (string memory) { |
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if (!_exists(tokenId)) _revert(URIQueryForNonexistentToken.selector); |
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string memory baseURI = _baseURI(); |
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return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, _toString(tokenId))) : ''; |
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} |
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/** |
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* @dev Base URI for computing {tokenURI}. If set, the resulting URI for each |
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* token will be the concatenation of the `baseURI` and the `tokenId`. Empty |
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* by default, it can be overridden in child contracts. |
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*/ |
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function _baseURI() internal view virtual returns (string memory) { |
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return ''; |
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} |
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// ============================================================= |
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// OWNERSHIPS OPERATIONS |
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// ============================================================= |
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/** |
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* @dev Returns the owner of the `tokenId` token. |
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* |
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* Requirements: |
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* |
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* - `tokenId` must exist. |
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*/ |
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function ownerOf(uint256 tokenId) public view virtual override returns (address) { |
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return address(uint160(_packedOwnershipOf(tokenId))); |
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} |
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/** |
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* @dev Gas spent here starts off proportional to the maximum mint batch size. |
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* It gradually moves to O(1) as tokens get transferred around over time. |
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*/ |
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function _ownershipOf(uint256 tokenId) internal view virtual returns (TokenOwnership memory) { |
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return _unpackedOwnership(_packedOwnershipOf(tokenId)); |
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} |
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/** |
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* @dev Returns the unpacked `TokenOwnership` struct at `index`. |
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*/ |
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function _ownershipAt(uint256 index) internal view virtual returns (TokenOwnership memory) { |
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return _unpackedOwnership(_packedOwnerships[index]); |
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} |
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/** |
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* @dev Returns whether the ownership slot at `index` is initialized. |
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* An uninitialized slot does not necessarily mean that the slot has no owner. |
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*/ |
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function _ownershipIsInitialized(uint256 index) internal view virtual returns (bool) { |
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return _packedOwnerships[index] != 0; |
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} |
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/** |
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* @dev Initializes the ownership slot minted at `index` for efficiency purposes. |
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*/ |
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function _initializeOwnershipAt(uint256 index) internal virtual { |
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if (_packedOwnerships[index] == uint256(0)) { |
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_packedOwnerships[index] = _packedOwnershipOf(index); |
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} |
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} |
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/** |
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* @dev Returns the packed ownership data of `tokenId`. |
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*/ |
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function _packedOwnershipOf(uint256 tokenId) private view returns (uint256 packed) { |
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if (_startTokenId() <= tokenId) { |
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packed = _packedOwnerships[tokenId]; |
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if (tokenId > _sequentialUpTo()) { |
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if (_packedOwnershipExists(packed)) return packed; |
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_revert(OwnerQueryForNonexistentToken.selector); |
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} |
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// If the data at the starting slot does not exist, start the scan. |
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if (packed == uint256(0)) { |
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if (tokenId >= _currentIndex) _revert(OwnerQueryForNonexistentToken.selector); |
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// Invariant: |
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// There will always be an initialized ownership slot |
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// (i.e. `ownership.addr != address(0) && ownership.burned == false`) |
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// before an unintialized ownership slot |
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// (i.e. `ownership.addr == address(0) && ownership.burned == false`) |
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// Hence, `tokenId` will not underflow. |
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// |
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// We can directly compare the packed value. |
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// If the address is zero, packed will be zero. |
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for (;;) { |
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unchecked { |
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packed = _packedOwnerships[--tokenId]; |
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} |
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if (packed == uint256(0)) continue; |
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if (packed & _BITMASK_BURNED == uint256(0)) return packed; |
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// Otherwise, the token is burned, and we must revert. |
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// This handles the case of batch burned tokens, where only the burned bit |
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// of the starting slot is set, and remaining slots are left uninitialized. |
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_revert(OwnerQueryForNonexistentToken.selector); |
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} |
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} |
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// Otherwise, the data exists and we can skip the scan. |
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// This is possible because we have already achieved the target condition. |
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// This saves 2143 gas on transfers of initialized tokens. |
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// If the token is not burned, return `packed`. Otherwise, revert. |
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if (packed & _BITMASK_BURNED == uint256(0)) return packed; |
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} |
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_revert(OwnerQueryForNonexistentToken.selector); |
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} |
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/** |
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* @dev Returns the unpacked `TokenOwnership` struct from `packed`. |
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*/ |
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function _unpackedOwnership(uint256 packed) private pure returns (TokenOwnership memory ownership) { |
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ownership.addr = address(uint160(packed)); |
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ownership.startTimestamp = uint64(packed >> _BITPOS_START_TIMESTAMP); |
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ownership.burned = packed & _BITMASK_BURNED != 0; |
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ownership.extraData = uint24(packed >> _BITPOS_EXTRA_DATA); |
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} |
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/** |
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* @dev Packs ownership data into a single uint256. |
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*/ |
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function _packOwnershipData(address owner, uint256 flags) private view returns (uint256 result) { |
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assembly { |
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// Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean. |
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owner := and(owner, _BITMASK_ADDRESS) |
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// `owner | (block.timestamp << _BITPOS_START_TIMESTAMP) | flags`. |
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result := or(owner, or(shl(_BITPOS_START_TIMESTAMP, timestamp()), flags)) |
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} |
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} |
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/** |
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* @dev Returns the `nextInitialized` flag set if `quantity` equals 1. |
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*/ |
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function _nextInitializedFlag(uint256 quantity) private pure returns (uint256 result) { |
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// For branchless setting of the `nextInitialized` flag. |
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assembly { |
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// `(quantity == 1) << _BITPOS_NEXT_INITIALIZED`. |
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result := shl(_BITPOS_NEXT_INITIALIZED, eq(quantity, 1)) |
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} |
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} |
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// ============================================================= |
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// APPROVAL OPERATIONS |
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// ============================================================= |
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/** |
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* @dev Gives permission to `to` to transfer `tokenId` token to another account. See {ERC721A-_approve}. |
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* |
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* Requirements: |
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* |
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* - The caller must own the token or be an approved operator. |
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*/ |
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function approve(address to, uint256 tokenId) public payable virtual override { |
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_approve(to, tokenId, true); |
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} |
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/** |
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* @dev Returns the account approved for `tokenId` token. |
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* |
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* Requirements: |
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* |
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* - `tokenId` must exist. |
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*/ |
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function getApproved(uint256 tokenId) public view virtual override returns (address) { |
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if (!_exists(tokenId)) _revert(ApprovalQueryForNonexistentToken.selector); |
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return _tokenApprovals[tokenId].value; |
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} |
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/** |
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* @dev Approve or remove `operator` as an operator for the caller. |
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* Operators can call {transferFrom} or {safeTransferFrom} |
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* for any token owned by the caller. |
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* |
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* Requirements: |
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* |
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* - The `operator` cannot be the caller. |
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* |
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* Emits an {ApprovalForAll} event. |
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*/ |
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function setApprovalForAll(address operator, bool approved) public virtual override { |
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_operatorApprovals[_msgSenderERC721A()][operator] = approved; |
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emit ApprovalForAll(_msgSenderERC721A(), operator, approved); |
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} |
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/** |
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* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`. |
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* |
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* See {setApprovalForAll}. |
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*/ |
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function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) { |
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return _operatorApprovals[owner][operator]; |
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} |
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/** |
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* @dev Returns whether `tokenId` exists. |
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* |
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* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}. |
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* |
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* Tokens start existing when they are minted. See {_mint}. |
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*/ |
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function _exists(uint256 tokenId) internal view virtual returns (bool result) { |
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if (_startTokenId() <= tokenId) { |
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if (tokenId > _sequentialUpTo()) return _packedOwnershipExists(_packedOwnerships[tokenId]); |
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if (tokenId < _currentIndex) { |
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uint256 packed; |
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while ((packed = _packedOwnerships[tokenId]) == uint256(0)) --tokenId; |
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result = packed & _BITMASK_BURNED == uint256(0); |
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} |
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} |
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} |
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/** |
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* @dev Returns whether `packed` represents a token that exists. |
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*/ |
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function _packedOwnershipExists(uint256 packed) private pure returns (bool result) { |
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assembly { |
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// The following is equivalent to `owner != address(0) && burned == false`. |
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// Symbolically tested. |
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result := gt(and(packed, _BITMASK_ADDRESS), and(packed, _BITMASK_BURNED)) |
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} |
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} |
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/** |
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* @dev Returns whether `msgSender` is equal to `approvedAddress` or `owner`. |
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*/ |
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function _isSenderApprovedOrOwner( |
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uint256 approvedAddressValue, |
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uint256 ownerMasked, |
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uint256 msgSenderMasked |
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) private pure returns (bool result) { |
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assembly { |
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result := or(eq(msgSenderMasked, ownerMasked), eq(msgSenderMasked, approvedAddressValue)) |
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} |
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} |
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/** |
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* @dev Returns the storage slot and value for the approved address of `tokenId` casted to a uint256. |
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*/ |
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function _getApprovedSlotAndValue(uint256 tokenId) |
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private |
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view |
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returns (uint256 approvedAddressSlot, uint256 approvedAddressValue) |
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{ |
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TokenApprovalRef storage tokenApproval = _tokenApprovals[tokenId]; |
|
// The following is equivalent to `approvedAddressValue = uint160(_tokenApprovals[tokenId].value)`. |
|
assembly { |
|
approvedAddressSlot := tokenApproval.slot |
|
approvedAddressValue := 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); |
|
uint256 fromMasked = uint160(from); |
|
|
|
if (uint160(prevOwnershipPacked) != fromMasked) _revert(TransferFromIncorrectOwner.selector); |
|
|
|
(uint256 approvedAddressSlot, uint256 approvedAddressValue) = _getApprovedSlotAndValue(tokenId); |
|
|
|
// The nested ifs save around 20+ gas over a compound boolean condition. |
|
if (!_isSenderApprovedOrOwner(approvedAddressValue, fromMasked, uint160(_msgSenderERC721A()))) |
|
if (!isApprovedForAll(from, _msgSenderERC721A())) _revert(TransferCallerNotOwnerNorApproved.selector); |
|
|
|
_beforeTokenTransfers(from, to, tokenId, 1); |
|
|
|
assembly { |
|
if approvedAddressValue { |
|
sstore(approvedAddressSlot, 0) // Equivalent to `delete _tokenApprovals[tokenId]`. |
|
} |
|
} |
|
|
|
// 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 == uint256(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] == uint256(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; |
|
} |
|
} |
|
} |
|
} |
|
|
|
// Mask to the lower 160 bits, in case the upper bits somehow aren't clean. |
|
uint256 toMasked = uint160(to); |
|
assembly { |
|
// 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. |
|
fromMasked, // `from`. |
|
toMasked, // `to`. |
|
tokenId // `tokenId`. |
|
) |
|
} |
|
if (toMasked == uint256(0)) _revert(TransferToZeroAddress.selector); |
|
|
|
_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.selector); |
|
} |
|
} |
|
|
|
/** |
|
* @dev Equivalent to `_batchTransferFrom(from, to, tokenIds)`. |
|
*/ |
|
function _batchTransferFrom( |
|
address from, |
|
address to, |
|
uint256[] memory tokenIds |
|
) internal virtual { |
|
_batchTransferFrom(address(0), from, to, tokenIds); |
|
} |
|
|
|
/** |
|
* @dev Transfers `tokenIds` in batch from `from` to `to`. |
|
* |
|
* Requirements: |
|
* |
|
* - `from` cannot be the zero address. |
|
* - `to` cannot be the zero address. |
|
* - `tokenIds` tokens must be owned by `from`. |
|
* - `tokenIds` must be strictly ascending. |
|
* - If `by` is not `from`, it must be approved to move these tokens |
|
* by either {approve} or {setApprovalForAll}. |
|
* |
|
* `by` is the address that to check token approval for. |
|
* If token approval check is not needed, pass in `address(0)` for `by`. |
|
* |
|
* Emits a {Transfer} event for each transfer. |
|
*/ |
|
function _batchTransferFrom( |
|
address by, |
|
address from, |
|
address to, |
|
uint256[] memory tokenIds |
|
) internal virtual { |
|
uint256 byMasked = uint160(by); |
|
uint256 fromMasked = uint160(from); |
|
uint256 toMasked = uint160(to); |
|
// Disallow transfer to zero address. |
|
if (toMasked == uint256(0)) _revert(TransferToZeroAddress.selector); |
|
// Whether `by` may transfer the tokens. |
|
bool mayTransfer = _orERC721A(byMasked == uint256(0), byMasked == fromMasked) || isApprovedForAll(from, by); |
|
|
|
// Early return if `tokenIds` is empty. |
|
if (tokenIds.length == uint256(0)) return; |
|
// The next `tokenId` to be minted (i.e. `_nextTokenId()`). |
|
uint256 end = _currentIndex; |
|
// Pointer to start and end (exclusive) of `tokenIds`. |
|
(uint256 ptr, uint256 ptrEnd) = _mdataERC721A(tokenIds); |
|
|
|
uint256 prevTokenId; |
|
uint256 prevOwnershipPacked; |
|
unchecked { |
|
do { |
|
uint256 tokenId = _mloadERC721A(ptr); |
|
uint256 miniBatchStart = tokenId; |
|
// Revert `tokenId` is out of bounds. |
|
if (_orERC721A(tokenId < _startTokenId(), end <= tokenId)) |
|
_revert(OwnerQueryForNonexistentToken.selector); |
|
// Revert if `tokenIds` is not strictly ascending. |
|
if (prevOwnershipPacked != 0) |
|
if (tokenId <= prevTokenId) _revert(TokenIdsNotStrictlyAscending.selector); |
|
// Scan backwards for an initialized packed ownership slot. |
|
// ERC721A's invariant guarantees that there will always be an initialized slot as long as |
|
// the start of the backwards scan falls within `[_startTokenId() .. _nextTokenId())`. |
|
for (uint256 j = tokenId; (prevOwnershipPacked = _packedOwnerships[j]) == uint256(0); ) --j; |
|
// If the initialized slot is burned, revert. |
|
if (prevOwnershipPacked & _BITMASK_BURNED != 0) _revert(OwnerQueryForNonexistentToken.selector); |
|
// Check that `tokenId` is owned by `from`. |
|
if (uint160(prevOwnershipPacked) != fromMasked) _revert(TransferFromIncorrectOwner.selector); |
|
|
|
do { |
|
(uint256 approvedAddressSlot, uint256 approvedAddressValue) = _getApprovedSlotAndValue(tokenId); |
|
_beforeTokenTransfers(address(uint160(fromMasked)), address(uint160(toMasked)), tokenId, 1); |
|
// Revert if the sender is not authorized to transfer the token. |
|
if (!mayTransfer) |
|
if (byMasked != approvedAddressValue) _revert(TransferCallerNotOwnerNorApproved.selector); |
|
assembly { |
|
if approvedAddressValue { |
|
sstore(approvedAddressSlot, 0) // Equivalent to `delete _tokenApprovals[tokenId]`. |
|
} |
|
// Emit the `Transfer` event. |
|
log4(0, 0, _TRANSFER_EVENT_SIGNATURE, fromMasked, toMasked, tokenId) |
|
} |
|
|
|
if (_mloadERC721A(ptr += 0x20) != ++tokenId) break; |
|
if (ptr == ptrEnd) break; |
|
} while (_packedOwnerships[tokenId] == uint256(0)); |
|
|
|
// Updates tokenId: |
|
// - `address` to the next owner. |
|
// - `startTimestamp` to the timestamp of transferring. |
|
// - `burned` to `false`. |
|
// - `nextInitialized` to `false`, as it is optional. |
|
_packedOwnerships[miniBatchStart] = _packOwnershipData( |
|
address(uint160(toMasked)), |
|
_nextExtraData(address(uint160(fromMasked)), address(uint160(toMasked)), prevOwnershipPacked) |
|
); |
|
uint256 miniBatchLength = tokenId - miniBatchStart; |
|
// Update the address data. |
|
_packedAddressData[address(uint160(fromMasked))] -= miniBatchLength; |
|
_packedAddressData[address(uint160(toMasked))] += miniBatchLength; |
|
// Initialize the next slot if needed. |
|
if (tokenId != end) |
|
if (_packedOwnerships[tokenId] == uint256(0)) _packedOwnerships[tokenId] = prevOwnershipPacked; |
|
// Perform the after hook for the batch. |
|
_afterTokenTransfers( |
|
address(uint160(fromMasked)), |
|
address(uint160(toMasked)), |
|
miniBatchStart, |
|
miniBatchLength |
|
); |
|
// Set the `prevTokenId` for checking that the `tokenIds` is strictly ascending. |
|
prevTokenId = tokenId - 1; |
|
} while (ptr != ptrEnd); |
|
} |
|
} |
|
|
|
/** |
|
* @dev Safely transfers `tokenIds` in batch from `from` to `to`. |
|
* |
|
* Requirements: |
|
* |
|
* - `from` cannot be the zero address. |
|
* - `to` cannot be the zero address. |
|
* - `tokenIds` tokens must be owned by `from`. |
|
* - If `by` is not `from`, it must be approved to move these tokens |
|
* by either {approve} or {setApprovalForAll}. |
|
* - If `to` refers to a smart contract, it must implement |
|
* {IERC721Receiver-onERC721Received}, which is called for each transferred token. |
|
* |
|
* `by` is the address that to check token approval for. |
|
* If token approval check is not needed, pass in `address(0)` for `by`. |
|
* |
|
* Emits a {Transfer} event for each transfer. |
|
*/ |
|
function _safeBatchTransferFrom( |
|
address by, |
|
address from, |
|
address to, |
|
uint256[] memory tokenIds, |
|
bytes memory _data |
|
) internal virtual { |
|
_batchTransferFrom(by, from, to, tokenIds); |
|
|
|
unchecked { |
|
if (to.code.length != 0) { |
|
for ((uint256 ptr, uint256 ptrEnd) = _mdataERC721A(tokenIds); ptr != ptrEnd; ptr += 0x20) { |
|
if (!_checkContractOnERC721Received(from, to, _mloadERC721A(ptr), _data)) { |
|
_revert(TransferToNonERC721ReceiverImplementer.selector); |
|
} |
|
} |
|
} |
|
} |
|
} |
|
|
|
/** |
|
* @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 == uint256(0)) { |
|
_revert(TransferToNonERC721ReceiverImplementer.selector); |
|
} |
|
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 == uint256(0)) _revert(MintZeroQuantity.selector); |
|
|
|
_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: |
|
// - `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) |
|
); |
|
|
|
// Updates: |
|
// - `balance += quantity`. |
|
// - `numberMinted += quantity`. |
|
// |
|
// We can directly add to the `balance` and `numberMinted`. |
|
_packedAddressData[to] += quantity * ((1 << _BITPOS_NUMBER_MINTED) | 1); |
|
|
|
// Mask to the lower 160 bits, in case the upper bits somehow aren't clean. |
|
uint256 toMasked = uint160(to); |
|
|
|
if (toMasked == uint256(0)) _revert(MintToZeroAddress.selector); |
|
|
|
uint256 end = startTokenId + quantity; |
|
uint256 tokenId = startTokenId; |
|
|
|
if (end - 1 > _sequentialUpTo()) _revert(SequentialMintExceedsLimit.selector); |
|
|
|
do { |
|
assembly { |
|
// 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`. |
|
tokenId // `tokenId`. |
|
) |
|
} |
|
// The `!=` check ensures that large values of `quantity` |
|
// that overflows uint256 will make the loop run out of gas. |
|
} while (++tokenId != end); |
|
|
|
_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.selector); |
|
if (quantity == uint256(0)) _revert(MintZeroQuantity.selector); |
|
if (quantity > _MAX_MINT_ERC2309_QUANTITY_LIMIT) _revert(MintERC2309QuantityExceedsLimit.selector); |
|
|
|
_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) |
|
); |
|
|
|
if (startTokenId + quantity - 1 > _sequentialUpTo()) _revert(SequentialMintExceedsLimit.selector); |
|
|
|
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.selector); |
|
} |
|
} while (index < end); |
|
// This prevents reentrancy to `_safeMint`. |
|
// It does not prevent reentrancy to `_safeMintSpot`. |
|
if (_currentIndex != end) revert(); |
|
} |
|
} |
|
} |
|
|
|
/** |
|
* @dev Equivalent to `_safeMint(to, quantity, '')`. |
|
*/ |
|
function _safeMint(address to, uint256 quantity) internal virtual { |
|
_safeMint(to, quantity, ''); |
|
} |
|
|
|
/** |
|
* @dev Mints a single token at `tokenId`. |
|
* |
|
* Note: A spot-minted `tokenId` that has been burned can be re-minted again. |
|
* |
|
* Requirements: |
|
* |
|
* - `to` cannot be the zero address. |
|
* - `tokenId` must be greater than `_sequentialUpTo()`. |
|
* - `tokenId` must not exist. |
|
* |
|
* Emits a {Transfer} event for each mint. |
|
*/ |
|
function _mintSpot(address to, uint256 tokenId) internal virtual { |
|
if (tokenId <= _sequentialUpTo()) _revert(SpotMintTokenIdTooSmall.selector); |
|
uint256 prevOwnershipPacked = _packedOwnerships[tokenId]; |
|
if (_packedOwnershipExists(prevOwnershipPacked)) _revert(TokenAlreadyExists.selector); |
|
|
|
_beforeTokenTransfers(address(0), to, tokenId, 1); |
|
|
|
// Overflows are incredibly unrealistic. |
|
// The `numberMinted` for `to` is incremented by 1, and has a max limit of 2**64 - 1. |
|
// `_spotMinted` is incremented by 1, and has a max limit of 2**256 - 1. |
|
unchecked { |
|
// Updates: |
|
// - `address` to the owner. |
|
// - `startTimestamp` to the timestamp of minting. |
|
// - `burned` to `false`. |
|
// - `nextInitialized` to `true` (as `quantity == 1`). |
|
_packedOwnerships[tokenId] = _packOwnershipData( |
|
to, |
|
_nextInitializedFlag(1) | _nextExtraData(address(0), to, prevOwnershipPacked) |
|
); |
|
|
|
// Updates: |
|
// - `balance += 1`. |
|
// - `numberMinted += 1`. |
|
// |
|
// We can directly add to the `balance` and `numberMinted`. |
|
_packedAddressData[to] += (1 << _BITPOS_NUMBER_MINTED) | 1; |
|
|
|
// Mask to the lower 160 bits, in case the upper bits somehow aren't clean. |
|
uint256 toMasked = uint160(to); |
|
|
|
if (toMasked == uint256(0)) _revert(MintToZeroAddress.selector); |
|
|
|
assembly { |
|
// 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`. |
|
tokenId // `tokenId`. |
|
) |
|
} |
|
|
|
++_spotMinted; |
|
} |
|
|
|
_afterTokenTransfers(address(0), to, tokenId, 1); |
|
} |
|
|
|
/** |
|
* @dev Safely mints a single token at `tokenId`. |
|
* |
|
* Note: A spot-minted `tokenId` that has been burned can be re-minted again. |
|
* |
|
* Requirements: |
|
* |
|
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}. |
|
* - `tokenId` must be greater than `_sequentialUpTo()`. |
|
* - `tokenId` must not exist. |
|
* |
|
* See {_mintSpot}. |
|
* |
|
* Emits a {Transfer} event. |
|
*/ |
|
function _safeMintSpot( |
|
address to, |
|
uint256 tokenId, |
|
bytes memory _data |
|
) internal virtual { |
|
_mintSpot(to, tokenId); |
|
|
|
unchecked { |
|
if (to.code.length != 0) { |
|
uint256 currentSpotMinted = _spotMinted; |
|
if (!_checkContractOnERC721Received(address(0), to, tokenId, _data)) { |
|
_revert(TransferToNonERC721ReceiverImplementer.selector); |
|
} |
|
// This prevents reentrancy to `_safeMintSpot`. |
|
// It does not prevent reentrancy to `_safeMint`. |
|
if (_spotMinted != currentSpotMinted) revert(); |
|
} |
|
} |
|
} |
|
|
|
/** |
|
* @dev Equivalent to `_safeMintSpot(to, tokenId, '')`. |
|
*/ |
|
function _safeMintSpot(address to, uint256 tokenId) internal virtual { |
|
_safeMintSpot(to, tokenId, ''); |
|
} |
|
|
|
// ============================================================= |
|
// APPROVAL OPERATIONS |
|
// ============================================================= |
|
|
|
/** |
|
* @dev Equivalent to `_approve(to, tokenId, false)`. |
|
*/ |
|
function _approve(address to, uint256 tokenId) internal virtual { |
|
_approve(to, tokenId, false); |
|
} |
|
|
|
/** |
|
* @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: |
|
* |
|
* - `tokenId` must exist. |
|
* |
|
* Emits an {Approval} event. |
|
*/ |
|
function _approve( |
|
address to, |
|
uint256 tokenId, |
|
bool approvalCheck |
|
) internal virtual { |
|
address owner = ownerOf(tokenId); |
|
|
|
if (approvalCheck && _msgSenderERC721A() != owner) |
|
if (!isApprovedForAll(owner, _msgSenderERC721A())) { |
|
_revert(ApprovalCallerNotOwnerNorApproved.selector); |
|
} |
|
|
|
_tokenApprovals[tokenId].value = to; |
|
emit Approval(owner, to, tokenId); |
|
} |
|
|
|
// ============================================================= |
|
// 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); |
|
|
|
uint256 fromMasked = uint160(prevOwnershipPacked); |
|
address from = address(uint160(fromMasked)); |
|
|
|
(uint256 approvedAddressSlot, uint256 approvedAddressValue) = _getApprovedSlotAndValue(tokenId); |
|
|
|
if (approvalCheck) { |
|
// The nested ifs save around 20+ gas over a compound boolean condition. |
|
if (!_isSenderApprovedOrOwner(approvedAddressValue, fromMasked, uint160(_msgSenderERC721A()))) |
|
if (!isApprovedForAll(from, _msgSenderERC721A())) _revert(TransferCallerNotOwnerNorApproved.selector); |
|
} |
|
|
|
_beforeTokenTransfers(from, address(0), tokenId, 1); |
|
|
|
assembly { |
|
if approvedAddressValue { |
|
sstore(approvedAddressSlot, 0) // Equivalent to `delete _tokenApprovals[tokenId]`. |
|
} |
|
} |
|
|
|
// 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 == uint256(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] == uint256(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 + _spotMinted` times. |
|
unchecked { |
|
_burnCounter++; |
|
} |
|
} |
|
|
|
/** |
|
* @dev Destroys `tokenIds`. |
|
* Approvals are not cleared when tokenIds are burned. |
|
* |
|
* Requirements: |
|
* |
|
* - `tokenIds` must exist. |
|
* - `tokenIds` must be strictly ascending. |
|
* - `by` must be approved to burn these tokens by either {approve} or {setApprovalForAll}. |
|
* |
|
* `by` is the address that to check token approval for. |
|
* If token approval check is not needed, pass in `address(0)` for `by`. |
|
* |
|
* Emits a {Transfer} event for each token burned. |
|
*/ |
|
function _batchBurn(address by, uint256[] memory tokenIds) internal virtual { |
|
// Early return if `tokenIds` is empty. |
|
if (tokenIds.length == uint256(0)) return; |
|
// The next `tokenId` to be minted (i.e. `_nextTokenId()`). |
|
uint256 end = _currentIndex; |
|
// Pointer to start and end (exclusive) of `tokenIds`. |
|
(uint256 ptr, uint256 ptrEnd) = _mdataERC721A(tokenIds); |
|
|
|
uint256 prevOwnershipPacked; |
|
address prevTokenOwner; |
|
uint256 prevTokenId; |
|
bool mayBurn; |
|
unchecked { |
|
do { |
|
uint256 tokenId = _mloadERC721A(ptr); |
|
uint256 miniBatchStart = tokenId; |
|
// Revert `tokenId` is out of bounds. |
|
if (_orERC721A(tokenId < _startTokenId(), end <= tokenId)) |
|
_revert(OwnerQueryForNonexistentToken.selector); |
|
// Revert if `tokenIds` is not strictly ascending. |
|
if (prevOwnershipPacked != 0) |
|
if (tokenId <= prevTokenId) _revert(TokenIdsNotStrictlyAscending.selector); |
|
// Scan backwards for an initialized packed ownership slot. |
|
// ERC721A's invariant guarantees that there will always be an initialized slot as long as |
|
// the start of the backwards scan falls within `[_startTokenId() .. _nextTokenId())`. |
|
for (uint256 j = tokenId; (prevOwnershipPacked = _packedOwnerships[j]) == uint256(0); ) --j; |
|
// If the initialized slot is burned, revert. |
|
if (prevOwnershipPacked & _BITMASK_BURNED != 0) _revert(OwnerQueryForNonexistentToken.selector); |
|
|
|
address tokenOwner = address(uint160(prevOwnershipPacked)); |
|
if (tokenOwner != prevTokenOwner) { |
|
prevTokenOwner = tokenOwner; |
|
mayBurn = _orERC721A(by == address(0), tokenOwner == by) || isApprovedForAll(tokenOwner, by); |
|
} |
|
|
|
do { |
|
(uint256 approvedAddressSlot, uint256 approvedAddressValue) = _getApprovedSlotAndValue(tokenId); |
|
_beforeTokenTransfers(tokenOwner, address(0), tokenId, 1); |
|
// Revert if the sender is not authorized to transfer the token. |
|
if (!mayBurn) |
|
if (uint160(by) != approvedAddressValue) _revert(TransferCallerNotOwnerNorApproved.selector); |
|
assembly { |
|
if approvedAddressValue { |
|
sstore(approvedAddressSlot, 0) // Equivalent to `delete _tokenApprovals[tokenId]`. |
|
} |
|
// Emit the `Transfer` event. |
|
log4(0, 0, _TRANSFER_EVENT_SIGNATURE, and(_BITMASK_ADDRESS, tokenOwner), 0, tokenId) |
|
} |
|
if (_mloadERC721A(ptr += 0x20) != ++tokenId) break; |
|
if (ptr == ptrEnd) break; |
|
} while (_packedOwnerships[tokenId] == uint256(0)); |
|
|
|
// Updates tokenId: |
|
// - `address` to the same `tokenOwner`. |
|
// - `startTimestamp` to the timestamp of transferring. |
|
// - `burned` to `true`. |
|
// - `nextInitialized` to `false`, as it is optional. |
|
_packedOwnerships[miniBatchStart] = _packOwnershipData( |
|
tokenOwner, |
|
_BITMASK_BURNED | _nextExtraData(tokenOwner, address(0), prevOwnershipPacked) |
|
); |
|
uint256 miniBatchLength = tokenId - miniBatchStart; |
|
// Update the address data. |
|
_packedAddressData[tokenOwner] += (miniBatchLength << _BITPOS_NUMBER_BURNED) - miniBatchLength; |
|
// Initialize the next slot if needed. |
|
if (tokenId != end) |
|
if (_packedOwnerships[tokenId] == uint256(0)) _packedOwnerships[tokenId] = prevOwnershipPacked; |
|
// Perform the after hook for the batch. |
|
_afterTokenTransfers(tokenOwner, address(0), miniBatchStart, miniBatchLength); |
|
// Set the `prevTokenId` for checking that the `tokenIds` is strictly ascending. |
|
prevTokenId = tokenId - 1; |
|
} while (ptr != ptrEnd); |
|
// Increment the overall burn counter. |
|
_burnCounter += tokenIds.length; |
|
} |
|
} |
|
|
|
// ============================================================= |
|
// 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 == uint256(0)) _revert(OwnershipNotInitializedForExtraData.selector); |
|
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; |
|
} |
|
|
|
// ============================================================= |
|
// PRIVATE HELPERS |
|
// ============================================================= |
|
|
|
/** |
|
* @dev Returns a memory pointer to the start of `a`'s data. |
|
*/ |
|
function _mdataERC721A(uint256[] memory a) private pure returns (uint256 start, uint256 end) { |
|
assembly { |
|
start := add(a, 0x20) |
|
end := add(start, shl(5, mload(a))) |
|
} |
|
} |
|
|
|
/** |
|
* @dev Returns the uint256 at `p` in memory. |
|
*/ |
|
function _mloadERC721A(uint256 p) private pure returns (uint256 result) { |
|
assembly { |
|
result := mload(p) |
|
} |
|
} |
|
|
|
/** |
|
* @dev Branchless boolean or. |
|
*/ |
|
function _orERC721A(bool a, bool b) private pure returns (bool result) { |
|
assembly { |
|
result := or(iszero(iszero(a)), iszero(iszero(b))) |
|
} |
|
} |
|
|
|
// ============================================================= |
|
// 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) |
|
} |
|
} |
|
|
|
/** |
|
* @dev For more efficient reverts. |
|
*/ |
|
function _revert(bytes4 errorSelector) internal pure { |
|
assembly { |
|
mstore(0x00, errorSelector) |
|
revert(0x00, 0x04) |
|
} |
|
} |
|
} |