// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)pragmasolidity ^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.
*/abstractcontractContext{
function_msgSender() internalviewvirtualreturns (address) {
returnmsg.sender;
}
function_msgData() internalviewvirtualreturns (bytescalldata) {
returnmsg.data;
}
}
// SPDX-License-Identifier: MIT// ERC721A Contracts v4.2.3// Creator: Chiru Labspragmasolidity ^0.8.4;import'./IERC721A.sol';
/**
* @dev Interface of ERC721 token receiver.
*/interfaceERC721A__IERC721Receiver{
functiononERC721Received(address operator,
addressfrom,
uint256 tokenId,
bytescalldata data
) externalreturns (bytes4);
}
/**
* @title ERC721A
*
* @dev Implementation of the [ERC721](https://eips.ethereum.org/EIPS/eip-721)
* Non-Fungible Token Standard, including the Metadata extension.
* Optimized for lower gas during batch mints.
*
* Token IDs are minted in sequential order (e.g. 0, 1, 2, 3, ...)
* starting from `_startTokenId()`.
*
* Assumptions:
*
* - An owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
* - The maximum token ID cannot exceed 2**256 - 1 (max value of uint256).
*/contractERC721AisIERC721A{
// Bypass for a `--via-ir` bug (https://github.com/chiru-labs/ERC721A/pull/364).structTokenApprovalRef {
address value;
}
// =============================================================// CONSTANTS// =============================================================// Mask of an entry in packed address data.uint256privateconstant _BITMASK_ADDRESS_DATA_ENTRY = (1<<64) -1;
// The bit position of `numberMinted` in packed address data.uint256privateconstant _BITPOS_NUMBER_MINTED =64;
// The bit position of `numberBurned` in packed address data.uint256privateconstant _BITPOS_NUMBER_BURNED =128;
// The bit position of `aux` in packed address data.uint256privateconstant _BITPOS_AUX =192;
// Mask of all 256 bits in packed address data except the 64 bits for `aux`.uint256privateconstant _BITMASK_AUX_COMPLEMENT = (1<<192) -1;
// The bit position of `startTimestamp` in packed ownership.uint256privateconstant _BITPOS_START_TIMESTAMP =160;
// The bit mask of the `burned` bit in packed ownership.uint256privateconstant _BITMASK_BURNED =1<<224;
// The bit position of the `nextInitialized` bit in packed ownership.uint256privateconstant _BITPOS_NEXT_INITIALIZED =225;
// The bit mask of the `nextInitialized` bit in packed ownership.uint256privateconstant _BITMASK_NEXT_INITIALIZED =1<<225;
// The bit position of `extraData` in packed ownership.uint256privateconstant _BITPOS_EXTRA_DATA =232;
// Mask of all 256 bits in a packed ownership except the 24 bits for `extraData`.uint256privateconstant _BITMASK_EXTRA_DATA_COMPLEMENT = (1<<232) -1;
// The mask of the lower 160 bits for addresses.uint256privateconstant _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.uint256privateconstant _MAX_MINT_ERC2309_QUANTITY_LIMIT =5000;
// The `Transfer` event signature is given by:// `keccak256(bytes("Transfer(address,address,uint256)"))`.bytes32privateconstant _TRANSFER_EVENT_SIGNATURE =0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef;
// =============================================================// STORAGE// =============================================================// The next token ID to be minted.uint256private _currentIndex;
// The number of tokens burned.uint256private _burnCounter;
// Token namestringprivate _name;
// Token symbolstringprivate _symbol;
// Mapping from token ID to ownership details// An empty struct value does not necessarily mean the token is unowned.// See {_packedOwnershipOf} implementation for details.//// Bits Layout:// - [0..159] `addr`// - [160..223] `startTimestamp`// - [224] `burned`// - [225] `nextInitialized`// - [232..255] `extraData`mapping(uint256=>uint256) private _packedOwnerships;
// Mapping owner address to address data.//// Bits Layout:// - [0..63] `balance`// - [64..127] `numberMinted`// - [128..191] `numberBurned`// - [192..255] `aux`mapping(address=>uint256) private _packedAddressData;
// Mapping from token ID to approved address.mapping(uint256=> TokenApprovalRef) private _tokenApprovals;
// Mapping from owner to operator approvalsmapping(address=>mapping(address=>bool)) private _operatorApprovals;
// =============================================================// CONSTRUCTOR// =============================================================constructor(stringmemory name_, stringmemory symbol_) {
_name = name_;
_symbol = symbol_;
_currentIndex = _startTokenId();
}
// =============================================================// TOKEN COUNTING OPERATIONS// =============================================================/**
* @dev Returns the starting token ID.
* To change the starting token ID, please override this function.
*/function_startTokenId() internalviewvirtualreturns (uint256) {
return1;
}
/**
* @dev Returns the next token ID to be minted.
*/function_nextTokenId() internalviewvirtualreturns (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}.
*/functiontotalSupply() publicviewvirtualoverridereturns (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.
*/functiontotalMinted() publicviewvirtualreturns (uint256) {
// Counter underflow is impossible as `_currentIndex` does not decrement,// and it is initialized to `_startTokenId()`.unchecked {
return _currentIndex - _startTokenId();
}
}
/**
* @dev Returns the total amount of tokens minted in the contract.
*/function_totalMinted() internalviewvirtualreturns (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() internalviewvirtualreturns (uint256) {
return _burnCounter;
}
// =============================================================// ADDRESS DATA OPERATIONS// =============================================================/**
* @dev Returns the number of tokens in `owner`'s account.
*/functionbalanceOf(address owner) publicviewvirtualoverridereturns (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) internalviewreturns (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) internalviewreturns (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) internalviewreturns (uint64) {
returnuint64(_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) internalvirtual{
uint256 packed = _packedAddressData[owner];
uint256 auxCasted;
// Cast `aux` with assembly to avoid redundant masking.assembly {
auxCasted := aux
}
packed = (packed & _BITMASK_AUX_COMPLEMENT) | (auxCasted << _BITPOS_AUX);
_packedAddressData[owner] = packed;
}
// =============================================================// IERC165// =============================================================/**
* @dev Returns true if this contract implements the interface defined by
* `interfaceId`. See the corresponding
* [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)
* to learn more about how these ids are created.
*
* This function call must use less than 30000 gas.
*/functionsupportsInterface(bytes4 interfaceId) publicviewvirtualoverridereturns (bool) {
// The interface IDs are constants representing the first 4 bytes// of the XOR of all function selectors in the interface.// See: [ERC165](https://eips.ethereum.org/EIPS/eip-165)// (e.g. `bytes4(i.functionA.selector ^ i.functionB.selector ^ ...)`)return
interfaceId ==0x01ffc9a7||// ERC165 interface ID for ERC165.
interfaceId ==0x80ac58cd||// ERC165 interface ID for ERC721.
interfaceId ==0x5b5e139f; // ERC165 interface ID for ERC721Metadata.
}
// =============================================================// IERC721Metadata// =============================================================/**
* @dev Returns the token collection name.
*/functionname() publicviewvirtualoverridereturns (stringmemory) {
return _name;
}
/**
* @dev Returns the token collection symbol.
*/functionsymbol() publicviewvirtualoverridereturns (stringmemory) {
return _symbol;
}
/**
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
*/functiontokenURI(uint256 tokenId) publicviewvirtualoverridereturns (stringmemory) {
if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
stringmemory baseURI = _baseURI();
returnbytes(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() internalviewvirtualreturns (stringmemory) {
return'';
}
// =============================================================// OWNERSHIPS OPERATIONS// =============================================================/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functionownerOf(uint256 tokenId) publicviewvirtualoverridereturns (address) {
returnaddress(uint160(_packedOwnershipOf(tokenId)));
}
/**
* @dev Gas spent here starts off proportional to the maximum mint batch size.
* It gradually moves to O(1) as tokens get transferred around over time.
*/function_ownershipOf(uint256 tokenId) internalviewvirtualreturns (TokenOwnership memory) {
return _unpackedOwnership(_packedOwnershipOf(tokenId));
}
/**
* @dev Returns the unpacked `TokenOwnership` struct at `index`.
*/function_ownershipAt(uint256 index) internalviewvirtualreturns (TokenOwnership memory) {
return _unpackedOwnership(_packedOwnerships[index]);
}
/**
* @dev Initializes the ownership slot minted at `index` for efficiency purposes.
*/function_initializeOwnershipAt(uint256 index) internalvirtual{
if (_packedOwnerships[index] ==0) {
_packedOwnerships[index] = _packedOwnershipOf(index);
}
}
/**
* Returns the packed ownership data of `tokenId`.
*/function_packedOwnershipOf(uint256 tokenId) privateviewreturns (uint256) {
uint256 curr = tokenId;
unchecked {
if (_startTokenId() <= curr)
if (curr < _currentIndex) {
uint256 packed = _packedOwnerships[curr];
// If not burned.if (packed & _BITMASK_BURNED ==0) {
// Invariant:// There will always be an initialized ownership slot// (i.e. `ownership.addr != address(0) && ownership.burned == false`)// before an unintialized ownership slot// (i.e. `ownership.addr == address(0) && ownership.burned == false`)// Hence, `curr` will not underflow.//// We can directly compare the packed value.// If the address is zero, packed will be zero.while (packed ==0) {
packed = _packedOwnerships[--curr];
}
return packed;
}
}
}
revert OwnerQueryForNonexistentToken();
}
/**
* @dev Returns the unpacked `TokenOwnership` struct from `packed`.
*/function_unpackedOwnership(uint256 packed) privatepurereturns (TokenOwnership memory ownership) {
ownership.addr =address(uint160(packed));
ownership.startTimestamp =uint64(packed >> _BITPOS_START_TIMESTAMP);
ownership.burned = packed & _BITMASK_BURNED !=0;
ownership.extraData =uint24(packed >> _BITPOS_EXTRA_DATA);
}
/**
* @dev Packs ownership data into a single uint256.
*/function_packOwnershipData(address owner, uint256 flags) privateviewreturns (uint256 result) {
assembly {
// Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean.
owner :=and(owner, _BITMASK_ADDRESS)
// `owner | (block.timestamp << _BITPOS_START_TIMESTAMP) | flags`.
result :=or(owner, or(shl(_BITPOS_START_TIMESTAMP, timestamp()), flags))
}
}
/**
* @dev Returns the `nextInitialized` flag set if `quantity` equals 1.
*/function_nextInitializedFlag(uint256 quantity) privatepurereturns (uint256 result) {
// For branchless setting of the `nextInitialized` flag.assembly {
// `(quantity == 1) << _BITPOS_NEXT_INITIALIZED`.
result :=shl(_BITPOS_NEXT_INITIALIZED, eq(quantity, 1))
}
}
// =============================================================// APPROVAL OPERATIONS// =============================================================/**
* @dev Gives permission to `to` to transfer `tokenId` token to another account.
* The approval is cleared when the token is transferred.
*
* Only a single account can be approved at a time, so approving the
* zero address clears previous approvals.
*
* Requirements:
*
* - The caller must own the token or be an approved operator.
* - `tokenId` must exist.
*
* Emits an {Approval} event.
*/functionapprove(address to, uint256 tokenId) publicpayablevirtualoverride{
address owner = ownerOf(tokenId);
if (_msgSenderERC721A() != owner)
if (!isApprovedForAll(owner, _msgSenderERC721A())) {
revert ApprovalCallerNotOwnerNorApproved();
}
_tokenApprovals[tokenId].value= to;
emit Approval(owner, to, tokenId);
}
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functiongetApproved(uint256 tokenId) publicviewvirtualoverridereturns (address) {
if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
return _tokenApprovals[tokenId].value;
}
/**
* @dev Approve or remove `operator` as an operator for the caller.
* Operators can call {transferFrom} or {safeTransferFrom}
* for any token owned by the caller.
*
* Requirements:
*
* - The `operator` cannot be the caller.
*
* Emits an {ApprovalForAll} event.
*/functionsetApprovalForAll(address operator, bool approved) publicvirtualoverride{
_operatorApprovals[_msgSenderERC721A()][operator] = approved;
emit ApprovalForAll(_msgSenderERC721A(), operator, approved);
}
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}.
*/functionisApprovedForAll(address owner, address operator) publicviewvirtualoverridereturns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev Returns whether `tokenId` exists.
*
* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
*
* Tokens start existing when they are minted. See {_mint}.
*/function_exists(uint256 tokenId) internalviewvirtualreturns (bool) {
return
_startTokenId() <= tokenId &&
tokenId < _currentIndex &&// If within bounds,
_packedOwnerships[tokenId] & _BITMASK_BURNED ==0; // and not burned.
}
/**
* @dev Returns whether `msgSender` is equal to `approvedAddress` or `owner`.
*/function_isSenderApprovedOrOwner(address approvedAddress,
address owner,
address msgSender
) privatepurereturns (bool result) {
assembly {
// Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean.
owner :=and(owner, _BITMASK_ADDRESS)
// Mask `msgSender` to the lower 160 bits, in case the upper bits somehow aren't clean.
msgSender :=and(msgSender, _BITMASK_ADDRESS)
// `msgSender == owner || msgSender == approvedAddress`.
result :=or(eq(msgSender, owner), eq(msgSender, approvedAddress))
}
}
/**
* @dev Returns the storage slot and value for the approved address of `tokenId`.
*/function_getApprovedSlotAndAddress(uint256 tokenId)
privateviewreturns (uint256 approvedAddressSlot, address approvedAddress)
{
TokenApprovalRef storage tokenApproval = _tokenApprovals[tokenId];
// The following is equivalent to `approvedAddress = _tokenApprovals[tokenId].value`.assembly {
approvedAddressSlot := tokenApproval.slot
approvedAddress :=sload(approvedAddressSlot)
}
}
// =============================================================// TRANSFER OPERATIONS// =============================================================/**
* @dev Transfers `tokenId` from `from` to `to`.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token
* by either {approve} or {setApprovalForAll}.
*
* Emits a {Transfer} event.
*/functiontransferFrom(addressfrom,
address to,
uint256 tokenId
) publicpayablevirtualoverride{
uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);
if (address(uint160(prevOwnershipPacked)) !=from) revert TransferFromIncorrectOwner();
(uint256 approvedAddressSlot, address approvedAddress) = _getApprovedSlotAndAddress(tokenId);
// The nested ifs save around 20+ gas over a compound boolean condition.if (!_isSenderApprovedOrOwner(approvedAddress, from, _msgSenderERC721A()))
if (!isApprovedForAll(from, _msgSenderERC721A())) revert TransferCallerNotOwnerNorApproved();
if (to ==address(0)) revert TransferToZeroAddress();
_beforeTokenTransfers(from, to, tokenId, 1);
// Clear approvals from the previous owner.assembly {
if approvedAddress {
// This is equivalent to `delete _tokenApprovals[tokenId]`.sstore(approvedAddressSlot, 0)
}
}
// Underflow of the sender's balance is impossible because we check for// ownership above and the recipient's balance can't realistically overflow.// Counter overflow is incredibly unrealistic as `tokenId` would have to be 2**256.unchecked {
// We can directly increment and decrement the balances.--_packedAddressData[from]; // Updates: `balance -= 1`.++_packedAddressData[to]; // Updates: `balance += 1`.// Updates:// - `address` to the next owner.// - `startTimestamp` to the timestamp of transfering.// - `burned` to `false`.// - `nextInitialized` to `true`.
_packedOwnerships[tokenId] = _packOwnershipData(
to,
_BITMASK_NEXT_INITIALIZED | _nextExtraData(from, to, prevOwnershipPacked)
);
// If the next slot may not have been initialized (i.e. `nextInitialized == false`) .if (prevOwnershipPacked & _BITMASK_NEXT_INITIALIZED ==0) {
uint256 nextTokenId = tokenId +1;
// If the next slot's address is zero and not burned (i.e. packed value is zero).if (_packedOwnerships[nextTokenId] ==0) {
// If the next slot is within bounds.if (nextTokenId != _currentIndex) {
// Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
_packedOwnerships[nextTokenId] = prevOwnershipPacked;
}
}
}
}
emit Transfer(from, to, tokenId);
_afterTokenTransfers(from, to, tokenId, 1);
}
/**
* @dev Equivalent to `safeTransferFrom(from, to, tokenId, '')`.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId
) publicpayablevirtualoverride{
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.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) publicpayablevirtualoverride{
transferFrom(from, to, tokenId);
if (to.code.length!=0)
if (!_checkContractOnERC721Received(from, to, tokenId, _data)) {
revert TransferToNonERC721ReceiverImplementer();
}
}
/**
* @dev Hook that is called before a set of serially-ordered token IDs
* are about to be transferred. This includes minting.
* And also called before burning one token.
*
* `startTokenId` - the first token ID to be transferred.
* `quantity` - the amount to be transferred.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, `tokenId` will be burned by `from`.
* - `from` and `to` are never both zero.
*/function_beforeTokenTransfers(addressfrom,
address to,
uint256 startTokenId,
uint256 quantity
) internalvirtual{}
/**
* @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(addressfrom,
address to,
uint256 startTokenId,
uint256 quantity
) internalvirtual{}
/**
* @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(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) privatereturns (bool) {
try ERC721A__IERC721Receiver(to).onERC721Received(_msgSenderERC721A(), from, tokenId, _data) returns (
bytes4 retval
) {
return retval == ERC721A__IERC721Receiver(to).onERC721Received.selector;
} catch (bytesmemory reason) {
if (reason.length==0) {
revert TransferToNonERC721ReceiverImplementer();
} else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
}
// =============================================================// MINT OPERATIONS// =============================================================/**
* @dev Mints `quantity` tokens and transfers them to `to`.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `quantity` must be greater than 0.
*
* Emits a {Transfer} event for each mint.
*/function_mint(address to, uint256 quantity) internalvirtual{
uint256 startTokenId = _currentIndex;
if (quantity ==0) revert MintZeroQuantity();
_beforeTokenTransfers(address(0), to, startTokenId, quantity);
// Overflows are incredibly unrealistic.// `balance` and `numberMinted` have a maximum limit of 2**64.// `tokenId` has a maximum limit of 2**256.unchecked {
// Updates:// - `balance += quantity`.// - `numberMinted += quantity`.//// We can directly add to the `balance` and `numberMinted`.
_packedAddressData[to] += quantity * ((1<< _BITPOS_NUMBER_MINTED) |1);
// Updates:// - `address` to the owner.// - `startTimestamp` to the timestamp of minting.// - `burned` to `false`.// - `nextInitialized` to `quantity == 1`.
_packedOwnerships[startTokenId] = _packOwnershipData(
to,
_nextInitializedFlag(quantity) | _nextExtraData(address(0), to, 0)
);
uint256 toMasked;
uint256 end = startTokenId + quantity;
// Use assembly to loop and emit the `Transfer` event for gas savings.// The duplicated `log4` removes an extra check and reduces stack juggling.// The assembly, together with the surrounding Solidity code, have been// delicately arranged to nudge the compiler into producing optimized opcodes.assembly {
// Mask `to` to the lower 160 bits, in case the upper bits somehow aren't clean.
toMasked :=and(to, _BITMASK_ADDRESS)
// Emit the `Transfer` event.log4(
0, // Start of data (0, since no data).0, // End of data (0, since no data).
_TRANSFER_EVENT_SIGNATURE, // Signature.0, // `address(0)`.
toMasked, // `to`.
startTokenId // `tokenId`.
)
// The `iszero(eq(,))` check ensures that large values of `quantity`// that overflows uint256 will make the loop run out of gas.// The compiler will optimize the `iszero` away for performance.for {
let tokenId :=add(startTokenId, 1)
} iszero(eq(tokenId, end)) {
tokenId :=add(tokenId, 1)
} {
// Emit the `Transfer` event. Similar to above.log4(0, 0, _TRANSFER_EVENT_SIGNATURE, 0, toMasked, tokenId)
}
}
if (toMasked ==0) revert MintToZeroAddress();
_currentIndex = end;
}
_afterTokenTransfers(address(0), to, startTokenId, quantity);
}
/**
* @dev Mints `quantity` tokens and transfers them to `to`.
*
* This function is intended for efficient minting only during contract creation.
*
* It emits only one {ConsecutiveTransfer} as defined in
* [ERC2309](https://eips.ethereum.org/EIPS/eip-2309),
* instead of a sequence of {Transfer} event(s).
*
* Calling this function outside of contract creation WILL make your contract
* non-compliant with the ERC721 standard.
* For full ERC721 compliance, substituting ERC721 {Transfer} event(s) with the ERC2309
* {ConsecutiveTransfer} event is only permissible during contract creation.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `quantity` must be greater than 0.
*
* Emits a {ConsecutiveTransfer} event.
*/function_mintERC2309(address to, uint256 quantity) internalvirtual{
uint256 startTokenId = _currentIndex;
if (to ==address(0)) revert MintToZeroAddress();
if (quantity ==0) revert MintZeroQuantity();
if (quantity > _MAX_MINT_ERC2309_QUANTITY_LIMIT) revert MintERC2309QuantityExceedsLimit();
_beforeTokenTransfers(address(0), to, startTokenId, quantity);
// Overflows are unrealistic due to the above check for `quantity` to be below the limit.unchecked {
// Updates:// - `balance += quantity`.// - `numberMinted += quantity`.//// We can directly add to the `balance` and `numberMinted`.
_packedAddressData[to] += quantity * ((1<< _BITPOS_NUMBER_MINTED) |1);
// Updates:// - `address` to the owner.// - `startTimestamp` to the timestamp of minting.// - `burned` to `false`.// - `nextInitialized` to `quantity == 1`.
_packedOwnerships[startTokenId] = _packOwnershipData(
to,
_nextInitializedFlag(quantity) | _nextExtraData(address(0), to, 0)
);
emit ConsecutiveTransfer(startTokenId, startTokenId + quantity -1, address(0), to);
_currentIndex = startTokenId + quantity;
}
_afterTokenTransfers(address(0), to, startTokenId, quantity);
}
/**
* @dev Safely mints `quantity` tokens and transfers them to `to`.
*
* Requirements:
*
* - If `to` refers to a smart contract, it must implement
* {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
* - `quantity` must be greater than 0.
*
* See {_mint}.
*
* Emits a {Transfer} event for each mint.
*/function_safeMint(address to,
uint256 quantity,
bytesmemory _data
) internalvirtual{
_mint(to, quantity);
unchecked {
if (to.code.length!=0) {
uint256 end = _currentIndex;
uint256 index = end - quantity;
do {
if (!_checkContractOnERC721Received(address(0), to, index++, _data)) {
revert TransferToNonERC721ReceiverImplementer();
}
} while (index < end);
// Reentrancy protection.if (_currentIndex != end) revert();
}
}
}
/**
* @dev Equivalent to `_safeMint(to, quantity, '')`.
*/function_safeMint(address to, uint256 quantity) internalvirtual{
_safeMint(to, quantity, '');
}
// =============================================================// BURN OPERATIONS// =============================================================/**
* @dev Equivalent to `_burn(tokenId, false)`.
*/function_burn(uint256 tokenId) internalvirtual{
_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) internalvirtual{
uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);
addressfrom=address(uint160(prevOwnershipPacked));
(uint256 approvedAddressSlot, address approvedAddress) = _getApprovedSlotAndAddress(tokenId);
if (approvalCheck) {
// The nested ifs save around 20+ gas over a compound boolean condition.if (!_isSenderApprovedOrOwner(approvedAddress, from, _msgSenderERC721A()))
if (!isApprovedForAll(from, _msgSenderERC721A())) revert TransferCallerNotOwnerNorApproved();
}
_beforeTokenTransfers(from, address(0), tokenId, 1);
// Clear approvals from the previous owner.assembly {
if approvedAddress {
// This is equivalent to `delete _tokenApprovals[tokenId]`.sstore(approvedAddressSlot, 0)
}
}
// Underflow of the sender's balance is impossible because we check for// ownership above and the recipient's balance can't realistically overflow.// Counter overflow is incredibly unrealistic as `tokenId` would have to be 2**256.unchecked {
// Updates:// - `balance -= 1`.// - `numberBurned += 1`.//// We can directly decrement the balance, and increment the number burned.// This is equivalent to `packed -= 1; packed += 1 << _BITPOS_NUMBER_BURNED;`.
_packedAddressData[from] += (1<< _BITPOS_NUMBER_BURNED) -1;
// Updates:// - `address` to the last owner.// - `startTimestamp` to the timestamp of burning.// - `burned` to `true`.// - `nextInitialized` to `true`.
_packedOwnerships[tokenId] = _packOwnershipData(
from,
(_BITMASK_BURNED | _BITMASK_NEXT_INITIALIZED) | _nextExtraData(from, address(0), prevOwnershipPacked)
);
// If the next slot may not have been initialized (i.e. `nextInitialized == false`) .if (prevOwnershipPacked & _BITMASK_NEXT_INITIALIZED ==0) {
uint256 nextTokenId = tokenId +1;
// If the next slot's address is zero and not burned (i.e. packed value is zero).if (_packedOwnerships[nextTokenId] ==0) {
// If the next slot is within bounds.if (nextTokenId != _currentIndex) {
// Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
_packedOwnerships[nextTokenId] = prevOwnershipPacked;
}
}
}
}
emit Transfer(from, address(0), tokenId);
_afterTokenTransfers(from, address(0), tokenId, 1);
// Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.unchecked {
_burnCounter++;
}
}
// =============================================================// EXTRA DATA OPERATIONS// =============================================================/**
* @dev Directly sets the extra data for the ownership data `index`.
*/function_setExtraDataAt(uint256 index, uint24 extraData) internalvirtual{
uint256 packed = _packedOwnerships[index];
if (packed ==0) revert OwnershipNotInitializedForExtraData();
uint256 extraDataCasted;
// Cast `extraData` with assembly to avoid redundant masking.assembly {
extraDataCasted := extraData
}
packed = (packed & _BITMASK_EXTRA_DATA_COMPLEMENT) | (extraDataCasted << _BITPOS_EXTRA_DATA);
_packedOwnerships[index] = packed;
}
/**
* @dev Called during each token transfer to set the 24bit `extraData` field.
* Intended to be overridden by the cosumer contract.
*
* `previousExtraData` - the value of `extraData` before transfer.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, `from`'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, `tokenId` will be burned by `from`.
* - `from` and `to` are never both zero.
*/function_extraData(addressfrom,
address to,
uint24 previousExtraData
) internalviewvirtualreturns (uint24) {}
/**
* @dev Returns the next extra data for the packed ownership data.
* The returned result is shifted into position.
*/function_nextExtraData(addressfrom,
address to,
uint256 prevOwnershipPacked
) privateviewreturns (uint256) {
uint24 extraData =uint24(prevOwnershipPacked >> _BITPOS_EXTRA_DATA);
returnuint256(_extraData(from, to, extraData)) << _BITPOS_EXTRA_DATA;
}
// =============================================================// OTHER OPERATIONS// =============================================================/**
* @dev Returns the message sender (defaults to `msg.sender`).
*
* If you are writing GSN compatible contracts, you need to override this function.
*/function_msgSenderERC721A() internalviewvirtualreturns (address) {
returnmsg.sender;
}
/**
* @dev Converts a uint256 to its ASCII string decimal representation.
*/function_toString(uint256 value) internalpurevirtualreturns (stringmemory 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-ignorefor { 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-ignoreifiszero(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)
}
}
}
Contract Source Code
File 7 of 15: IERC721A.sol
// SPDX-License-Identifier: MIT// ERC721A Contracts v4.2.3// Creator: Chiru Labspragmasolidity ^0.8.4;/**
* @dev Interface of ERC721A.
*/interfaceIERC721A{
/**
* The caller must own the token or be an approved operator.
*/errorApprovalCallerNotOwnerNorApproved();
/**
* The token does not exist.
*/errorApprovalQueryForNonexistentToken();
/**
* Cannot query the balance for the zero address.
*/errorBalanceQueryForZeroAddress();
/**
* Cannot mint to the zero address.
*/errorMintToZeroAddress();
/**
* The quantity of tokens minted must be more than zero.
*/errorMintZeroQuantity();
/**
* The token does not exist.
*/errorOwnerQueryForNonexistentToken();
/**
* The caller must own the token or be an approved operator.
*/errorTransferCallerNotOwnerNorApproved();
/**
* The token must be owned by `from`.
*/errorTransferFromIncorrectOwner();
/**
* Cannot safely transfer to a contract that does not implement the
* ERC721Receiver interface.
*/errorTransferToNonERC721ReceiverImplementer();
/**
* Cannot transfer to the zero address.
*/errorTransferToZeroAddress();
/**
* The token does not exist.
*/errorURIQueryForNonexistentToken();
/**
* The `quantity` minted with ERC2309 exceeds the safety limit.
*/errorMintERC2309QuantityExceedsLimit();
/**
* The `extraData` cannot be set on an unintialized ownership slot.
*/errorOwnershipNotInitializedForExtraData();
// =============================================================// STRUCTS// =============================================================structTokenOwnership {
// The address of the owner.address addr;
// Stores the start time of ownership with minimal overhead for tokenomics.uint64 startTimestamp;
// Whether the token has been burned.bool burned;
// Arbitrary data similar to `startTimestamp` that can be set via {_extraData}.uint24 extraData;
}
// =============================================================// TOKEN COUNTERS// =============================================================/**
* @dev Returns the total number of tokens in existence.
* Burned tokens will reduce the count.
* To get the total number of tokens minted, please see {_totalMinted}.
*/functiontotalSupply() externalviewreturns (uint256);
// =============================================================// IERC165// =============================================================/**
* @dev Returns true if this contract implements the interface defined by
* `interfaceId`. See the corresponding
* [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)
* to learn more about how these ids are created.
*
* This function call must use less than 30000 gas.
*/functionsupportsInterface(bytes4 interfaceId) externalviewreturns (bool);
// =============================================================// IERC721// =============================================================/**
* @dev Emitted when `tokenId` token is transferred from `from` to `to`.
*/eventTransfer(addressindexedfrom,
addressindexed to,
uint256indexed tokenId
);
/**
* @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
*/eventApproval(addressindexed owner,
addressindexed approved,
uint256indexed tokenId
);
/**
* @dev Emitted when `owner` enables or disables
* (`approved`) `operator` to manage all of its assets.
*/eventApprovalForAll(addressindexed owner,
addressindexed operator,
bool approved
);
/**
* @dev Returns the number of tokens in `owner`'s account.
*/functionbalanceOf(address owner) externalviewreturns (uint256 balance);
/**
* @dev Returns the owner of the `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functionownerOf(uint256 tokenId) externalviewreturns (address owner);
/**
* @dev Safely transfers `tokenId` token from `from` to `to`,
* checking first that contract recipients are aware of the ERC721 protocol
* to prevent tokens from being forever locked.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If the caller is not `from`, it must be have been allowed to move
* this token by either {approve} or {setApprovalForAll}.
* - If `to` refers to a smart contract, it must implement
* {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId,
bytescalldata data
) externalpayable;
/**
* @dev Equivalent to `safeTransferFrom(from, to, tokenId, '')`.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId
) externalpayable;
/**
* @dev Transfers `tokenId` from `from` to `to`.
*
* WARNING: Usage of this method is discouraged, use {safeTransferFrom}
* whenever possible.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
* - If the caller is not `from`, it must be approved to move this token
* by either {approve} or {setApprovalForAll}.
*
* Emits a {Transfer} event.
*/functiontransferFrom(addressfrom,
address to,
uint256 tokenId
) externalpayable;
/**
* @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.
*/functionapprove(address to, uint256 tokenId) externalpayable;
/**
* @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.
*/functionsetApprovalForAll(address operator, bool _approved) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functiongetApproved(uint256 tokenId)
externalviewreturns (address operator);
/**
* @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}.
*/functionisApprovedForAll(address owner, address operator)
externalviewreturns (bool);
// =============================================================// IERC721Metadata// =============================================================/**
* @dev Returns the token collection name.
*/functionname() externalviewreturns (stringmemory);
/**
* @dev Returns the token collection symbol.
*/functionsymbol() externalviewreturns (stringmemory);
/**
* @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.
*/functiontokenURI(uint256 tokenId) externalviewreturns (stringmemory);
// =============================================================// IERC2309// =============================================================/**
* @dev Emitted when tokens in `fromTokenId` to `toTokenId`
* (inclusive) is transferred from `from` to `to`, as defined in the
* [ERC2309](https://eips.ethereum.org/EIPS/eip-2309) standard.
*
* See {_mintERC2309} for more details.
*/eventConsecutiveTransfer(uint256indexed fromTokenId,
uint256 toTokenId,
addressindexedfrom,
addressindexed to
);
}
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)pragmasolidity ^0.8.0;/**
* @dev Standard math utilities missing in the Solidity language.
*/libraryMath{
enumRounding {
Down, // Toward negative infinity
Up, // Toward infinity
Zero // Toward zero
}
/**
* @dev Returns the largest of two numbers.
*/functionmax(uint256 a, uint256 b) internalpurereturns (uint256) {
return a > b ? a : b;
}
/**
* @dev Returns the smallest of two numbers.
*/functionmin(uint256 a, uint256 b) internalpurereturns (uint256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two numbers. The result is rounded towards
* zero.
*/functionaverage(uint256 a, uint256 b) internalpurereturns (uint256) {
// (a + b) / 2 can overflow.return (a & b) + (a ^ b) /2;
}
/**
* @dev Returns the ceiling of the division of two numbers.
*
* This differs from standard division with `/` in that it rounds up instead
* of rounding down.
*/functionceilDiv(uint256 a, uint256 b) internalpurereturns (uint256) {
// (a + b - 1) / b can overflow on addition, so we distribute.return a ==0 ? 0 : (a -1) / b +1;
}
/**
* @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
* @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
* with further edits by Uniswap Labs also under MIT license.
*/functionmulDiv(uint256 x,
uint256 y,
uint256 denominator
) internalpurereturns (uint256 result) {
unchecked {
// 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use// use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256// variables such that product = prod1 * 2^256 + prod0.uint256 prod0; // Least significant 256 bits of the productuint256 prod1; // Most significant 256 bits of the productassembly {
let mm :=mulmod(x, y, not(0))
prod0 :=mul(x, y)
prod1 :=sub(sub(mm, prod0), lt(mm, prod0))
}
// Handle non-overflow cases, 256 by 256 division.if (prod1 ==0) {
return prod0 / denominator;
}
// Make sure the result is less than 2^256. Also prevents denominator == 0.require(denominator > prod1);
///////////////////////////////////////////////// 512 by 256 division.///////////////////////////////////////////////// Make division exact by subtracting the remainder from [prod1 prod0].uint256 remainder;
assembly {
// Compute remainder using mulmod.
remainder :=mulmod(x, y, denominator)
// Subtract 256 bit number from 512 bit number.
prod1 :=sub(prod1, gt(remainder, prod0))
prod0 :=sub(prod0, remainder)
}
// Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.// See https://cs.stackexchange.com/q/138556/92363.// Does not overflow because the denominator cannot be zero at this stage in the function.uint256 twos = denominator & (~denominator +1);
assembly {
// Divide denominator by twos.
denominator :=div(denominator, twos)
// Divide [prod1 prod0] by twos.
prod0 :=div(prod0, twos)
// Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
twos :=add(div(sub(0, twos), twos), 1)
}
// Shift in bits from prod1 into prod0.
prod0 |= prod1 * twos;
// Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such// that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for// four bits. That is, denominator * inv = 1 mod 2^4.uint256 inverse = (3* denominator) ^2;
// Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works// in modular arithmetic, doubling the correct bits in each step.
inverse *=2- denominator * inverse; // inverse mod 2^8
inverse *=2- denominator * inverse; // inverse mod 2^16
inverse *=2- denominator * inverse; // inverse mod 2^32
inverse *=2- denominator * inverse; // inverse mod 2^64
inverse *=2- denominator * inverse; // inverse mod 2^128
inverse *=2- denominator * inverse; // inverse mod 2^256// Because the division is now exact we can divide by multiplying with the modular inverse of denominator.// This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is// less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1// is no longer required.
result = prod0 * inverse;
return result;
}
}
/**
* @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
*/functionmulDiv(uint256 x,
uint256 y,
uint256 denominator,
Rounding rounding
) internalpurereturns (uint256) {
uint256 result = mulDiv(x, y, denominator);
if (rounding == Rounding.Up &&mulmod(x, y, denominator) >0) {
result +=1;
}
return result;
}
/**
* @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
*
* Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
*/functionsqrt(uint256 a) internalpurereturns (uint256) {
if (a ==0) {
return0;
}
// For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.//// We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have// `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.//// This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`// → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`// → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`//// Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.uint256 result =1<< (log2(a) >>1);
// At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,// since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at// every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision// into the expected uint128 result.unchecked {
result = (result + a / result) >>1;
result = (result + a / result) >>1;
result = (result + a / result) >>1;
result = (result + a / result) >>1;
result = (result + a / result) >>1;
result = (result + a / result) >>1;
result = (result + a / result) >>1;
return min(result, a / result);
}
}
/**
* @notice Calculates sqrt(a), following the selected rounding direction.
*/functionsqrt(uint256 a, Rounding rounding) internalpurereturns (uint256) {
unchecked {
uint256 result = sqrt(a);
return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
}
}
/**
* @dev Return the log in base 2, rounded down, of a positive value.
* Returns 0 if given 0.
*/functionlog2(uint256 value) internalpurereturns (uint256) {
uint256 result =0;
unchecked {
if (value >>128>0) {
value >>=128;
result +=128;
}
if (value >>64>0) {
value >>=64;
result +=64;
}
if (value >>32>0) {
value >>=32;
result +=32;
}
if (value >>16>0) {
value >>=16;
result +=16;
}
if (value >>8>0) {
value >>=8;
result +=8;
}
if (value >>4>0) {
value >>=4;
result +=4;
}
if (value >>2>0) {
value >>=2;
result +=2;
}
if (value >>1>0) {
result +=1;
}
}
return result;
}
/**
* @dev Return the log in base 2, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/functionlog2(uint256 value, Rounding rounding) internalpurereturns (uint256) {
unchecked {
uint256 result =log2(value);
return result + (rounding == Rounding.Up &&1<< result < value ? 1 : 0);
}
}
/**
* @dev Return the log in base 10, rounded down, of a positive value.
* Returns 0 if given 0.
*/functionlog10(uint256 value) internalpurereturns (uint256) {
uint256 result =0;
unchecked {
if (value >=10**64) {
value /=10**64;
result +=64;
}
if (value >=10**32) {
value /=10**32;
result +=32;
}
if (value >=10**16) {
value /=10**16;
result +=16;
}
if (value >=10**8) {
value /=10**8;
result +=8;
}
if (value >=10**4) {
value /=10**4;
result +=4;
}
if (value >=10**2) {
value /=10**2;
result +=2;
}
if (value >=10**1) {
result +=1;
}
}
return result;
}
/**
* @dev Return the log in base 10, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/functionlog10(uint256 value, Rounding rounding) internalpurereturns (uint256) {
unchecked {
uint256 result = log10(value);
return result + (rounding == Rounding.Up &&10**result < value ? 1 : 0);
}
}
/**
* @dev Return the log in base 256, rounded down, of a positive value.
* Returns 0 if given 0.
*
* Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
*/functionlog256(uint256 value) internalpurereturns (uint256) {
uint256 result =0;
unchecked {
if (value >>128>0) {
value >>=128;
result +=16;
}
if (value >>64>0) {
value >>=64;
result +=8;
}
if (value >>32>0) {
value >>=32;
result +=4;
}
if (value >>16>0) {
value >>=16;
result +=2;
}
if (value >>8>0) {
result +=1;
}
}
return result;
}
/**
* @dev Return the log in base 10, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/functionlog256(uint256 value, Rounding rounding) internalpurereturns (uint256) {
unchecked {
uint256 result = log256(value);
return result + (rounding == Rounding.Up &&1<< (result *8) < value ? 1 : 0);
}
}
}
Contract Source Code
File 10 of 15: MerkleProof.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/MerkleProof.sol)pragmasolidity ^0.8.0;/**
* @dev These functions deal with verification of Merkle Tree proofs.
*
* The tree and the proofs can be generated using our
* https://github.com/OpenZeppelin/merkle-tree[JavaScript library].
* You will find a quickstart guide in the readme.
*
* WARNING: You should avoid using leaf values that are 64 bytes long prior to
* hashing, or use a hash function other than keccak256 for hashing leaves.
* This is because the concatenation of a sorted pair of internal nodes in
* the merkle tree could be reinterpreted as a leaf value.
* OpenZeppelin's JavaScript library generates merkle trees that are safe
* against this attack out of the box.
*/libraryMerkleProof{
/**
* @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.
*/functionverify(bytes32[] memory proof,
bytes32 root,
bytes32 leaf
) internalpurereturns (bool) {
return processProof(proof, leaf) == root;
}
/**
* @dev Calldata version of {verify}
*
* _Available since v4.7._
*/functionverifyCalldata(bytes32[] calldata proof,
bytes32 root,
bytes32 leaf
) internalpurereturns (bool) {
return processProofCalldata(proof, leaf) == root;
}
/**
* @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
* from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
* hash matches the root of the tree. When processing the proof, the pairs
* of leafs & pre-images are assumed to be sorted.
*
* _Available since v4.4._
*/functionprocessProof(bytes32[] memory proof, bytes32 leaf) internalpurereturns (bytes32) {
bytes32 computedHash = leaf;
for (uint256 i =0; i < proof.length; i++) {
computedHash = _hashPair(computedHash, proof[i]);
}
return computedHash;
}
/**
* @dev Calldata version of {processProof}
*
* _Available since v4.7._
*/functionprocessProofCalldata(bytes32[] calldata proof, bytes32 leaf) internalpurereturns (bytes32) {
bytes32 computedHash = leaf;
for (uint256 i =0; i < proof.length; i++) {
computedHash = _hashPair(computedHash, proof[i]);
}
return computedHash;
}
/**
* @dev Returns true if the `leaves` can be simultaneously proven to be a part of a merkle tree defined by
* `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
*
* CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
*
* _Available since v4.7._
*/functionmultiProofVerify(bytes32[] memory proof,
bool[] memory proofFlags,
bytes32 root,
bytes32[] memory leaves
) internalpurereturns (bool) {
return processMultiProof(proof, proofFlags, leaves) == root;
}
/**
* @dev Calldata version of {multiProofVerify}
*
* CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
*
* _Available since v4.7._
*/functionmultiProofVerifyCalldata(bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32 root,
bytes32[] memory leaves
) internalpurereturns (bool) {
return processMultiProofCalldata(proof, proofFlags, leaves) == root;
}
/**
* @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction
* proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another
* leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false
* respectively.
*
* CAUTION: Not all merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree
* is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the
* tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).
*
* _Available since v4.7._
*/functionprocessMultiProof(bytes32[] memory proof,
bool[] memory proofFlags,
bytes32[] memory leaves
) internalpurereturns (bytes32 merkleRoot) {
// This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by// consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the// `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of// the merkle tree.uint256 leavesLen = leaves.length;
uint256 totalHashes = proofFlags.length;
// Check proof validity.require(leavesLen + proof.length-1== totalHashes, "MerkleProof: invalid multiproof");
// The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using// `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".bytes32[] memory hashes =newbytes32[](totalHashes);
uint256 leafPos =0;
uint256 hashPos =0;
uint256 proofPos =0;
// At each step, we compute the next hash using two values:// - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we// get the next hash.// - depending on the flag, either another value for the "main queue" (merging branches) or an element from the// `proof` array.for (uint256 i =0; i < totalHashes; i++) {
bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
hashes[i] = _hashPair(a, b);
}
if (totalHashes >0) {
return hashes[totalHashes -1];
} elseif (leavesLen >0) {
return leaves[0];
} else {
return proof[0];
}
}
/**
* @dev Calldata version of {processMultiProof}.
*
* CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.
*
* _Available since v4.7._
*/functionprocessMultiProofCalldata(bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32[] memory leaves
) internalpurereturns (bytes32 merkleRoot) {
// This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by// consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the// `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of// the merkle tree.uint256 leavesLen = leaves.length;
uint256 totalHashes = proofFlags.length;
// Check proof validity.require(leavesLen + proof.length-1== totalHashes, "MerkleProof: invalid multiproof");
// The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using// `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".bytes32[] memory hashes =newbytes32[](totalHashes);
uint256 leafPos =0;
uint256 hashPos =0;
uint256 proofPos =0;
// At each step, we compute the next hash using two values:// - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we// get the next hash.// - depending on the flag, either another value for the "main queue" (merging branches) or an element from the// `proof` array.for (uint256 i =0; i < totalHashes; i++) {
bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
hashes[i] = _hashPair(a, b);
}
if (totalHashes >0) {
return hashes[totalHashes -1];
} elseif (leavesLen >0) {
return leaves[0];
} else {
return proof[0];
}
}
function_hashPair(bytes32 a, bytes32 b) privatepurereturns (bytes32) {
return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
}
function_efficientHash(bytes32 a, bytes32 b) privatepurereturns (bytes32 value) {
/// @solidity memory-safe-assemblyassembly {
mstore(0x00, a)
mstore(0x20, b)
value :=keccak256(0x00, 0x40)
}
}
}
Contract Source Code
File 11 of 15: OperatorFilterer.sol
// SPDX-License-Identifier: MITpragmasolidity ^0.8.13;import {IOperatorFilterRegistry} from"./IOperatorFilterRegistry.sol";
abstractcontractOperatorFilterer{
errorOperatorNotAllowed(address operator);
IOperatorFilterRegistry constant operatorFilterRegistry =
IOperatorFilterRegistry(0x000000000000AAeB6D7670E522A718067333cd4E);
constructor(address subscriptionOrRegistrantToCopy, bool subscribe) {
// If an inheriting token contract is deployed to a network without the registry deployed, the modifier// will not revert, but the contract will need to be registered with the registry once it is deployed in// order for the modifier to filter addresses.if (address(operatorFilterRegistry).code.length>0) {
if (subscribe) {
operatorFilterRegistry.registerAndSubscribe(address(this), subscriptionOrRegistrantToCopy);
} else {
if (subscriptionOrRegistrantToCopy !=address(0)) {
operatorFilterRegistry.registerAndCopyEntries(address(this), subscriptionOrRegistrantToCopy);
} else {
operatorFilterRegistry.register(address(this));
}
}
}
}
modifieronlyAllowedOperator(addressfrom) virtual{
// Check registry code length to facilitate testing in environments without a deployed registry.if (address(operatorFilterRegistry).code.length>0) {
// Allow spending tokens from addresses with balance// Note that this still allows listings and marketplaces with escrow to transfer tokens if transferred// from an EOA.if (from==msg.sender) {
_;
return;
}
if (
!(
operatorFilterRegistry.isOperatorAllowed(address(this), msg.sender)
&& operatorFilterRegistry.isOperatorAllowed(address(this), from)
)
) {
revert OperatorNotAllowed(msg.sender);
}
}
_;
}
}
Contract Source Code
File 12 of 15: Ownable.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)pragmasolidity ^0.8.0;import"../utils/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.
*/abstractcontractOwnableisContext{
addressprivate _owner;
eventOwnershipTransferred(addressindexed previousOwner, addressindexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/constructor() {
_transferOwnership(_msgSender());
}
/**
* @dev Throws if called by any account other than the owner.
*/modifieronlyOwner() {
_checkOwner();
_;
}
/**
* @dev Returns the address of the current owner.
*/functionowner() publicviewvirtualreturns (address) {
return _owner;
}
/**
* @dev Throws if the sender is not the owner.
*/function_checkOwner() internalviewvirtual{
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.
*/functionrenounceOwnership() publicvirtualonlyOwner{
_transferOwnership(address(0));
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/functiontransferOwnership(address newOwner) publicvirtualonlyOwner{
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) internalvirtual{
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
Contract Source Code
File 13 of 15: ReentrancyGuard.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)pragmasolidity ^0.8.0;/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/abstractcontractReentrancyGuard{
// Booleans are more expensive than uint256 or any type that takes up a full// word because each write operation emits an extra SLOAD to first read the// slot's contents, replace the bits taken up by the boolean, and then write// back. This is the compiler's defense against contract upgrades and// pointer aliasing, and it cannot be disabled.// The values being non-zero value makes deployment a bit more expensive,// but in exchange the refund on every call to nonReentrant will be lower in// amount. Since refunds are capped to a percentage of the total// transaction's gas, it is best to keep them low in cases like this one, to// increase the likelihood of the full refund coming into effect.uint256privateconstant _NOT_ENTERED =1;
uint256privateconstant _ENTERED =2;
uint256private _status;
constructor() {
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and making it call a
* `private` function that does the actual work.
*/modifiernonReentrant() {
_nonReentrantBefore();
_;
_nonReentrantAfter();
}
function_nonReentrantBefore() private{
// On the first call to nonReentrant, _status will be _NOT_ENTEREDrequire(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
}
function_nonReentrantAfter() private{
// By storing the original value once again, a refund is triggered (see// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
Contract Source Code
File 14 of 15: SafeMath.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)pragmasolidity ^0.8.0;// CAUTION// This version of SafeMath should only be used with Solidity 0.8 or later,// because it relies on the compiler's built in overflow checks./**
* @dev Wrappers over Solidity's arithmetic operations.
*
* NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
* now has built in overflow checking.
*/librarySafeMath{
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryAdd(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
unchecked {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
}
/**
* @dev Returns the subtraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontrySub(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
unchecked {
if (b > a) return (false, 0);
return (true, a - b);
}
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryMul(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
unchecked {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the// benefit is lost if 'b' is also tested.// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522if (a ==0) return (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/functiontryDiv(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
unchecked {
if (b ==0) return (false, 0);
return (true, a / b);
}
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/functiontryMod(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
unchecked {
if (b ==0) return (false, 0);
return (true, a % b);
}
}
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/functionadd(uint256 a, uint256 b) internalpurereturns (uint256) {
return a + b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/functionsub(uint256 a, uint256 b) internalpurereturns (uint256) {
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/functionmul(uint256 a, uint256 b) internalpurereturns (uint256) {
return a * b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator.
*
* Requirements:
*
* - The divisor cannot be zero.
*/functiondiv(uint256 a, uint256 b) internalpurereturns (uint256) {
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functionmod(uint256 a, uint256 b) internalpurereturns (uint256) {
return a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/functionsub(uint256 a,
uint256 b,
stringmemory errorMessage
) internalpurereturns (uint256) {
unchecked {
require(b <= a, errorMessage);
return a - b;
}
}
/**
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functiondiv(uint256 a,
uint256 b,
stringmemory errorMessage
) internalpurereturns (uint256) {
unchecked {
require(b >0, errorMessage);
return a / b;
}
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/functionmod(uint256 a,
uint256 b,
stringmemory errorMessage
) internalpurereturns (uint256) {
unchecked {
require(b >0, errorMessage);
return a % b;
}
}
}
Contract Source Code
File 15 of 15: Strings.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.8.0) (utils/Strings.sol)pragmasolidity ^0.8.0;import"./math/Math.sol";
/**
* @dev String operations.
*/libraryStrings{
bytes16privateconstant _SYMBOLS ="0123456789abcdef";
uint8privateconstant _ADDRESS_LENGTH =20;
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/functiontoString(uint256 value) internalpurereturns (stringmemory) {
unchecked {
uint256 length = Math.log10(value) +1;
stringmemory buffer =newstring(length);
uint256 ptr;
/// @solidity memory-safe-assemblyassembly {
ptr :=add(buffer, add(32, length))
}
while (true) {
ptr--;
/// @solidity memory-safe-assemblyassembly {
mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
}
value /=10;
if (value ==0) break;
}
return buffer;
}
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
*/functiontoHexString(uint256 value) internalpurereturns (stringmemory) {
unchecked {
return toHexString(value, Math.log256(value) +1);
}
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
*/functiontoHexString(uint256 value, uint256 length) internalpurereturns (stringmemory) {
bytesmemory buffer =newbytes(2* length +2);
buffer[0] ="0";
buffer[1] ="x";
for (uint256 i =2* length +1; i >1; --i) {
buffer[i] = _SYMBOLS[value &0xf];
value >>=4;
}
require(value ==0, "Strings: hex length insufficient");
returnstring(buffer);
}
/**
* @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
*/functiontoHexString(address addr) internalpurereturns (stringmemory) {
return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
}
}
