Contract Name:
APileOfSnow
Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity >=0.8.6;
import "./ERC721AQueryable.sol";
import "./Ownable.sol";
import "./MerkleProof.sol";
contract APileOfSnow is ERC721AQueryable, Ownable{
uint public maxSupply = 3333;
uint public maxPerWallet = 2;
bool public wlMintOpen = false;
bool public mintOpen = false;
string internal baseTokenURI = "ipfs://QmQjJ4DfEDier7ajd1GrD6dMvAL6qVCaJnKuGPs5usm8vd";
bytes32 public merkleRoot = "";
constructor() ERC721A("A Pile Of Snow", "APileOfSnow") {}
function _startTokenId() internal view virtual override returns (uint256) {
return 1;
}
function toggleMint() external onlyOwner {
wlMintOpen = false;
mintOpen = !mintOpen;
}
function toggleWhitelistMint() external onlyOwner {
mintOpen = false;
wlMintOpen = !wlMintOpen;
}
function setBaseTokenURI(string calldata _uri) external onlyOwner {
baseTokenURI = _uri;
}
function setMerkleRoot(bytes32 _root) external onlyOwner {
merkleRoot = _root;
}
function _baseURI() internal override view returns (string memory) {
return baseTokenURI;
}
function tokenURI(uint256 tokenId) public view virtual override(ERC721A, IERC721A) returns (string memory) {
if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
return _baseURI();
}
function mintAdmin(address to, uint qty) external onlyOwner {
_mintTo(to, qty);
}
function mint(uint qty) external payable {
require(mintOpen, "Public sale not active");
_mintCheck(qty);
}
function whitelistMint(uint qty, bytes32[] calldata proof) external payable {
require(wlMintOpen, "Whitelist sale not active");
require(MerkleProof.verify(proof, merkleRoot, keccak256(abi.encodePacked(msg.sender))), "Not whitelisted!");
_mintCheck(qty);
}
function _mintCheck(uint qty) internal {
require(qty > 0, "Can't mint 0");
require(qty + _numberMinted(_msgSender()) <= maxPerWallet, "Max mint per wallet reached");
_mintTo(_msgSender(), qty);
}
function _mintTo(address to, uint qty) internal {
require(qty + totalSupply() + _totalBurned() <= maxSupply, "Exceeds total supply");
_mint(to, qty);
}
function totalBurned() external view returns (uint256) {
return _totalBurned();
}
function mintedBySender() external view returns (uint256) {
return _numberMinted(_msgSender());
}
function burnedByOwner(address owner) external view returns (uint256) {
return _numberBurned(owner);
}
function melt(uint256 tokenId) external {
_burn(tokenId, true);
}
function withdraw() external onlyOwner {
payable(_msgSender()).transfer(address(this).balance);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
* @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;
}
}
// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.1.0
// Creator: Chiru Labs
pragma solidity ^0.8.4;
import './IERC721A.sol';
/**
* @dev ERC721 token receiver interface.
*/
interface ERC721A__IERC721Receiver {
function onERC721Received(
address operator,
address from,
uint256 tokenId,
bytes calldata data
) external returns (bytes4);
}
/**
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard,
* including the Metadata extension. Built to optimize for lower gas during batch mints.
*
* Assumes serials are sequentially minted starting at `_startTokenId()`
* (defaults to 0, e.g. 0, 1, 2, 3..).
*
* Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
*
* Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
*/
contract ERC721A is IERC721A {
// 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 tokenId of the next token 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 => address) private _tokenApprovals;
// Mapping from owner to operator approvals
mapping(address => mapping(address => bool)) private _operatorApprovals;
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
_currentIndex = _startTokenId();
}
/**
* @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 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 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 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 returns (uint256) {
return _burnCounter;
}
/**
* @dev See {IERC165-supportsInterface}.
*/
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: 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.
}
/**
* @dev See {IERC721-balanceOf}.
*/
function balanceOf(address owner) public view 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 {
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;
}
/**
* 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 ownership that has an address and is not burned
// before an ownership that does not have an address and is not burned.
// Hence, curr will not underflow.
//
// We can directly compare the packed value.
// If the address is zero, packed is zero.
while (packed == 0) {
packed = _packedOwnerships[--curr];
}
return packed;
}
}
}
revert OwnerQueryForNonexistentToken();
}
/**
* 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);
}
/**
* Returns the unpacked `TokenOwnership` struct at `index`.
*/
function _ownershipAt(uint256 index) internal view returns (TokenOwnership memory) {
return _unpackedOwnership(_packedOwnerships[index]);
}
/**
* @dev Initializes the ownership slot minted at `index` for efficiency purposes.
*/
function _initializeOwnershipAt(uint256 index) internal {
if (_packedOwnerships[index] == 0) {
_packedOwnerships[index] = _packedOwnershipOf(index);
}
}
/**
* Gas spent here starts off proportional to the maximum mint batch size.
* It gradually moves to O(1) as tokens get transferred around in the collection over time.
*/
function _ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
return _unpackedOwnership(_packedOwnershipOf(tokenId));
}
/**
* @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 See {IERC721-ownerOf}.
*/
function ownerOf(uint256 tokenId) public view override returns (address) {
return address(uint160(_packedOwnershipOf(tokenId)));
}
/**
* @dev See {IERC721Metadata-name}.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/
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 '';
}
/**
* @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))
}
}
/**
* @dev See {IERC721-approve}.
*/
function approve(address to, uint256 tokenId) public override {
address owner = ownerOf(tokenId);
if (_msgSenderERC721A() != owner)
if (!isApprovedForAll(owner, _msgSenderERC721A())) {
revert ApprovalCallerNotOwnerNorApproved();
}
_tokenApprovals[tokenId] = to;
emit Approval(owner, to, tokenId);
}
/**
* @dev See {IERC721-getApproved}.
*/
function getApproved(uint256 tokenId) public view override returns (address) {
if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/
function setApprovalForAll(address operator, bool approved) public virtual override {
if (operator == _msgSenderERC721A()) revert ApproveToCaller();
_operatorApprovals[_msgSenderERC721A()][operator] = approved;
emit ApprovalForAll(_msgSenderERC721A(), operator, approved);
}
/**
* @dev See {IERC721-isApprovedForAll}.
*/
function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId
) public virtual override {
safeTransferFrom(from, to, tokenId, '');
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId,
bytes memory _data
) public virtual override {
transferFrom(from, to, tokenId);
if (to.code.length != 0)
if (!_checkContractOnERC721Received(from, to, tokenId, _data)) {
revert TransferToNonERC721ReceiverImplementer();
}
}
/**
* @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 (`_mint`),
*/
function _exists(uint256 tokenId) internal view returns (bool) {
return
_startTokenId() <= tokenId &&
tokenId < _currentIndex && // If within bounds,
_packedOwnerships[tokenId] & BITMASK_BURNED == 0; // and not burned.
}
/**
* @dev Equivalent to `_safeMint(to, quantity, '')`.
*/
function _safeMint(address to, uint256 quantity) internal {
_safeMint(to, 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 {
_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 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 {
uint256 startTokenId = _currentIndex;
if (to == address(0)) revert MintToZeroAddress();
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 tokenId = startTokenId;
uint256 end = startTokenId + quantity;
do {
emit Transfer(address(0), to, tokenId++);
} 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 {
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 Returns the storage slot and value for the approved address of `tokenId`.
*/
function _getApprovedAddress(uint256 tokenId)
private
view
returns (uint256 approvedAddressSlot, address approvedAddress)
{
mapping(uint256 => address) storage tokenApprovalsPtr = _tokenApprovals;
// The following is equivalent to `approvedAddress = _tokenApprovals[tokenId]`.
assembly {
// Compute the slot.
mstore(0x00, tokenId)
mstore(0x20, tokenApprovalsPtr.slot)
approvedAddressSlot := keccak256(0x00, 0x40)
// Load the slot's value from storage.
approvedAddress := sload(approvedAddressSlot)
}
}
/**
* @dev Returns whether the `approvedAddress` is equals to `from` or `msgSender`.
*/
function _isOwnerOrApproved(
address approvedAddress,
address from,
address msgSender
) private pure returns (bool result) {
assembly {
// Mask `from` to the lower 160 bits, in case the upper bits somehow aren't clean.
from := and(from, BITMASK_ADDRESS)
// Mask `msgSender` to the lower 160 bits, in case the upper bits somehow aren't clean.
msgSender := and(msgSender, BITMASK_ADDRESS)
// `msgSender == from || msgSender == approvedAddress`.
result := or(eq(msgSender, from), eq(msgSender, approvedAddress))
}
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address from,
address to,
uint256 tokenId
) public virtual override {
uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);
if (address(uint160(prevOwnershipPacked)) != from) revert TransferFromIncorrectOwner();
(uint256 approvedAddressSlot, address approvedAddress) = _getApprovedAddress(tokenId);
// The nested ifs save around 20+ gas over a compound boolean condition.
if (!_isOwnerOrApproved(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 `_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) = _getApprovedAddress(tokenId);
if (approvalCheck) {
// The nested ifs save around 20+ gas over a compound boolean condition.
if (!_isOwnerOrApproved(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++;
}
}
/**
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target contract.
*
* @param from address representing the previous owner of the given token ID
* @param to target address that will receive the tokens
* @param tokenId uint256 ID of the token to be transferred
* @param _data bytes optional data to send along with the call
* @return bool 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))
}
}
}
}
/**
* @dev Directly sets the extra data for the ownership data `index`.
*/
function _setExtraDataAt(uint256 index, uint24 extraData) internal {
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 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;
}
/**
* @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 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 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 returns (string memory ptr) {
assembly {
// The maximum value of a uint256 contains 78 digits (1 byte per digit),
// but we allocate 128 bytes to keep the free memory pointer 32-byte word aliged.
// We will need 1 32-byte word to store the length,
// and 3 32-byte words to store a maximum of 78 digits. Total: 32 + 3 * 32 = 128.
ptr := add(mload(0x40), 128)
// Update the free memory pointer to allocate.
mstore(0x40, ptr)
// Cache the end of the memory to calculate the length later.
let end := ptr
// We write the string from the rightmost digit to the leftmost digit.
// The following is essentially a do-while loop that also handles the zero case.
// Costs a bit more than early returning for the zero case,
// but cheaper in terms of deployment and overall runtime costs.
for {
// Initialize and perform the first pass without check.
let temp := value
// Move the pointer 1 byte leftwards to point to an empty character slot.
ptr := sub(ptr, 1)
// Write the character to the pointer. 48 is the ASCII index of '0'.
mstore8(ptr, add(48, mod(temp, 10)))
temp := div(temp, 10)
} temp {
// Keep dividing `temp` until zero.
temp := div(temp, 10)
} {
// Body of the for loop.
ptr := sub(ptr, 1)
mstore8(ptr, add(48, mod(temp, 10)))
}
let length := sub(end, ptr)
// Move the pointer 32 bytes leftwards to make room for the length.
ptr := sub(ptr, 32)
// Store the length.
mstore(ptr, length)
}
}
}
// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.1.0
// Creator: Chiru Labs
pragma solidity ^0.8.4;
import './IERC721AQueryable.sol';
import './ERC721A.sol';
/**
* @title ERC721A Queryable
* @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 pfp 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;
}
}
}
// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.1.0
// Creator: Chiru Labs
pragma solidity ^0.8.4;
/**
* @dev Interface of an ERC721A compliant contract.
*/
interface IERC721A {
/**
* The caller must own the token or be an approved operator.
*/
error ApprovalCallerNotOwnerNorApproved();
/**
* The token does not exist.
*/
error ApprovalQueryForNonexistentToken();
/**
* The caller cannot approve to their own address.
*/
error ApproveToCaller();
/**
* 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();
struct TokenOwnership {
// The address of the owner.
address addr;
// Keeps track of 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 through `_extraData`.
uint24 extraData;
}
/**
* @dev Returns the total amount of tokens stored by the contract.
*
* Burned tokens are calculated here, use `_totalMinted()` if you want to count just minted tokens.
*/
function totalSupply() external view returns (uint256);
// ==============================
// IERC165
// ==============================
/**
* @dev Returns true if this contract implements the interface defined by
* `interfaceId`. See the corresponding
* https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
* to learn more about how these ids are created.
*
* This function call must use less than 30 000 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`.
*
* 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 calldata data
) external;
/**
* @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
) external;
/**
* @dev Transfers `tokenId` token 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;
/**
* @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;
/**
* @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 standard. See `_mintERC2309` for more details.
*/
event ConsecutiveTransfer(uint256 indexed fromTokenId, uint256 toTokenId, address indexed from, address indexed to);
}
// SPDX-License-Identifier: MIT
// ERC721A Contracts v4.1.0
// Creator: Chiru Labs
pragma solidity ^0.8.4;
import './IERC721A.sol';
/**
* @dev Interface of an ERC721AQueryable compliant contract.
*/
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`
*
* If the `tokenId` is burned:
* - `addr` = `<Address of owner before token was burned>`
* - `startTimestamp` = `<Timestamp when token was burned>`
* - `burned = `true`
*
* Otherwise:
* - `addr` = `<Address of owner>`
* - `startTimestamp` = `<Timestamp of start of ownership>`
* - `burned = `false`
*/
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 pfp collections should be fine).
*/
function tokensOfOwner(address owner) external view returns (uint256[] memory);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
/**
* @dev These functions deal with verification of Merkle Trees proofs.
*
* The proofs can be generated using the JavaScript library
* https://github.com/miguelmota/merkletreejs[merkletreejs].
* Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
*
* See `test/utils/cryptography/MerkleProof.test.js` for some examples.
*/
library MerkleProof {
/**
* @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
* defined by `root`. For this, a `proof` must be provided, containing
* sibling hashes on the branch from the leaf to the root of the tree. Each
* pair of leaves and each pair of pre-images are assumed to be sorted.
*/
function verify(
bytes32[] memory proof,
bytes32 root,
bytes32 leaf
) internal pure returns (bool) {
bytes32 computedHash = leaf;
for (uint256 i = 0; i < proof.length; i++) {
bytes32 proofElement = proof[i];
if (computedHash <= proofElement) {
// Hash(current computed hash + current element of the proof)
computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
} else {
// Hash(current element of the proof + current computed hash)
computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
}
}
// Check if the computed hash (root) is equal to the provided root
return computedHash == root;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "./Context.sol";
/**
* @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.
*
* By default, the owner account will be the one that deploys the contract. 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;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
_transferOwnership(_msgSender());
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing 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 {
require(newOwner != address(0), "Ownable: new owner is the zero address");
_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);
}
}