// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)pragmasolidity ^0.8.0;/**
* @dev Collection of functions related to the address type
*/libraryAddress{
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/functionisContract(address account) internalviewreturns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in// construction, since the code is only stored at the end of the// constructor execution.uint256 size;
assembly {
size :=extcodesize(account)
}
return size >0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/functionsendValue(addresspayable recipient, uint256 amount) internal{
require(address(this).balance>= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/functionfunctionCall(address target, bytesmemory data) internalreturns (bytesmemory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/functionfunctionCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalreturns (bytesmemory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/functionfunctionCallWithValue(address target,
bytesmemory data,
uint256 value
) internalreturns (bytesmemory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/functionfunctionCallWithValue(address target,
bytesmemory data,
uint256 value,
stringmemory errorMessage
) internalreturns (bytesmemory) {
require(address(this).balance>= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
(bool success, bytesmemory returndata) = target.call{value: value}(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/functionfunctionStaticCall(address target, bytesmemory data) internalviewreturns (bytesmemory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/functionfunctionStaticCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalviewreturns (bytesmemory) {
require(isContract(target), "Address: static call to non-contract");
(bool success, bytesmemory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/functionfunctionDelegateCall(address target, bytesmemory data) internalreturns (bytesmemory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/functionfunctionDelegateCall(address target,
bytesmemory data,
stringmemory errorMessage
) internalreturns (bytesmemory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytesmemory returndata) = target.delegatecall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason using the provided one.
*
* _Available since v4.3._
*/functionverifyCallResult(bool success,
bytesmemory returndata,
stringmemory errorMessage
) internalpurereturns (bytesmemory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if presentif (returndata.length>0) {
// The easiest way to bubble the revert reason is using memory via assemblyassembly {
let returndata_size :=mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
Contract Source Code
File 2 of 12: Context.sol
// 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;
}
}
Contract Source Code
File 3 of 12: Counters.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/Counters.sol)pragmasolidity ^0.8.0;/**
* @title Counters
* @author Matt Condon (@shrugs)
* @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
* of elements in a mapping, issuing ERC721 ids, or counting request ids.
*
* Include with `using Counters for Counters.Counter;`
*/libraryCounters{
structCounter {
// This variable should never be directly accessed by users of the library: interactions must be restricted to// the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add// this feature: see https://github.com/ethereum/solidity/issues/4637uint256 _value; // default: 0
}
functioncurrent(Counter storage counter) internalviewreturns (uint256) {
return counter._value;
}
functionincrement(Counter storage counter) internal{
unchecked {
counter._value +=1;
}
}
functiondecrement(Counter storage counter) internal{
uint256 value = counter._value;
require(value >0, "Counter: decrement overflow");
unchecked {
counter._value = value -1;
}
}
functionreset(Counter storage counter) internal{
counter._value =0;
}
}
Contract Source Code
File 4 of 12: ERC165.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)pragmasolidity ^0.8.0;import"./IERC165.sol";
/**
* @dev Implementation of the {IERC165} interface.
*
* Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
* for the additional interface id that will be supported. For example:
*
* ```solidity
* function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
* return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
* }
* ```
*
* Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
*/abstractcontractERC165isIERC165{
/**
* @dev See {IERC165-supportsInterface}.
*/functionsupportsInterface(bytes4 interfaceId) publicviewvirtualoverridereturns (bool) {
return interfaceId ==type(IERC165).interfaceId;
}
}
Contract Source Code
File 5 of 12: ERC721.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC721/ERC721.sol)pragmasolidity ^0.8.0;import"./IERC721.sol";
import"./IERC721Receiver.sol";
import"./extensions/IERC721Metadata.sol";
import"../../utils/Address.sol";
import"../../utils/Context.sol";
import"../../utils/Strings.sol";
import"../../utils/introspection/ERC165.sol";
/**
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
* the Metadata extension, but not including the Enumerable extension, which is available separately as
* {ERC721Enumerable}.
*/contractERC721isContext, ERC165, IERC721, IERC721Metadata{
usingAddressforaddress;
usingStringsforuint256;
// Token namestringprivate _name;
// Token symbolstringprivate _symbol;
// Mapping from token ID to owner addressmapping(uint256=>address) private _owners;
// Mapping owner address to token countmapping(address=>uint256) private _balances;
// Mapping from token ID to approved addressmapping(uint256=>address) private _tokenApprovals;
// Mapping from owner to operator approvalsmapping(address=>mapping(address=>bool)) private _operatorApprovals;
/**
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
*/constructor(stringmemory name_, stringmemory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev See {IERC165-supportsInterface}.
*/functionsupportsInterface(bytes4 interfaceId) publicviewvirtualoverride(ERC165, IERC165) returns (bool) {
return
interfaceId ==type(IERC721).interfaceId||
interfaceId ==type(IERC721Metadata).interfaceId||super.supportsInterface(interfaceId);
}
/**
* @dev See {IERC721-balanceOf}.
*/functionbalanceOf(address owner) publicviewvirtualoverridereturns (uint256) {
require(owner !=address(0), "ERC721: balance query for the zero address");
return _balances[owner];
}
/**
* @dev See {IERC721-ownerOf}.
*/functionownerOf(uint256 tokenId) publicviewvirtualoverridereturns (address) {
address owner = _owners[tokenId];
require(owner !=address(0), "ERC721: owner query for nonexistent token");
return owner;
}
/**
* @dev See {IERC721Metadata-name}.
*/functionname() publicviewvirtualoverridereturns (stringmemory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/functionsymbol() publicviewvirtualoverridereturns (stringmemory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/functiontokenURI(uint256 tokenId) publicviewvirtualoverridereturns (stringmemory) {
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
stringmemory baseURI = _baseURI();
returnbytes(baseURI).length>0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
}
/**
* @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, can be overriden in child contracts.
*/function_baseURI() internalviewvirtualreturns (stringmemory) {
return"";
}
/**
* @dev See {IERC721-approve}.
*/functionapprove(address to, uint256 tokenId) publicvirtualoverride{
address owner = ERC721.ownerOf(tokenId);
require(to != owner, "ERC721: approval to current owner");
require(
_msgSender() == owner || isApprovedForAll(owner, _msgSender()),
"ERC721: approve caller is not owner nor approved for all"
);
_approve(to, tokenId);
}
/**
* @dev See {IERC721-getApproved}.
*/functiongetApproved(uint256 tokenId) publicviewvirtualoverridereturns (address) {
require(_exists(tokenId), "ERC721: approved query for nonexistent token");
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/functionsetApprovalForAll(address operator, bool approved) publicvirtualoverride{
_setApprovalForAll(_msgSender(), operator, approved);
}
/**
* @dev See {IERC721-isApprovedForAll}.
*/functionisApprovedForAll(address owner, address operator) publicviewvirtualoverridereturns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev See {IERC721-transferFrom}.
*/functiontransferFrom(addressfrom,
address to,
uint256 tokenId
) publicvirtualoverride{
//solhint-disable-next-line max-line-lengthrequire(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_transfer(from, to, tokenId);
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId
) publicvirtualoverride{
safeTransferFrom(from, to, tokenId, "");
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) publicvirtualoverride{
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_safeTransfer(from, to, tokenId, _data);
}
/**
* @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.
*
* `_data` is additional data, it has no specified format and it is sent in call to `to`.
*
* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
* implement alternative mechanisms to perform token transfer, such as signature-based.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/function_safeTransfer(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) internalvirtual{
_transfer(from, to, tokenId);
require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
}
/**
* @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`),
* and stop existing when they are burned (`_burn`).
*/function_exists(uint256 tokenId) internalviewvirtualreturns (bool) {
return _owners[tokenId] !=address(0);
}
/**
* @dev Returns whether `spender` is allowed to manage `tokenId`.
*
* Requirements:
*
* - `tokenId` must exist.
*/function_isApprovedOrOwner(address spender, uint256 tokenId) internalviewvirtualreturns (bool) {
require(_exists(tokenId), "ERC721: operator query for nonexistent token");
address owner = ERC721.ownerOf(tokenId);
return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
}
/**
* @dev Safely mints `tokenId` and transfers it to `to`.
*
* Requirements:
*
* - `tokenId` must not exist.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/function_safeMint(address to, uint256 tokenId) internalvirtual{
_safeMint(to, tokenId, "");
}
/**
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
*/function_safeMint(address to,
uint256 tokenId,
bytesmemory _data
) internalvirtual{
_mint(to, tokenId);
require(
_checkOnERC721Received(address(0), to, tokenId, _data),
"ERC721: transfer to non ERC721Receiver implementer"
);
}
/**
* @dev Mints `tokenId` and transfers it to `to`.
*
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
*
* Requirements:
*
* - `tokenId` must not exist.
* - `to` cannot be the zero address.
*
* Emits a {Transfer} event.
*/function_mint(address to, uint256 tokenId) internalvirtual{
require(to !=address(0), "ERC721: mint to the zero address");
require(!_exists(tokenId), "ERC721: token already minted");
_beforeTokenTransfer(address(0), to, tokenId);
_balances[to] +=1;
_owners[tokenId] = to;
emit Transfer(address(0), to, tokenId);
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/function_burn(uint256 tokenId) internalvirtual{
address owner = ERC721.ownerOf(tokenId);
_beforeTokenTransfer(owner, address(0), tokenId);
// Clear approvals
_approve(address(0), tokenId);
_balances[owner] -=1;
delete _owners[tokenId];
emit Transfer(owner, address(0), tokenId);
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
*
* Emits a {Transfer} event.
*/function_transfer(addressfrom,
address to,
uint256 tokenId
) internalvirtual{
require(ERC721.ownerOf(tokenId) ==from, "ERC721: transfer of token that is not own");
require(to !=address(0), "ERC721: transfer to the zero address");
_beforeTokenTransfer(from, to, tokenId);
// Clear approvals from the previous owner
_approve(address(0), tokenId);
_balances[from] -=1;
_balances[to] +=1;
_owners[tokenId] = to;
emit Transfer(from, to, tokenId);
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits a {Approval} event.
*/function_approve(address to, uint256 tokenId) internalvirtual{
_tokenApprovals[tokenId] = to;
emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
}
/**
* @dev Approve `operator` to operate on all of `owner` tokens
*
* Emits a {ApprovalForAll} event.
*/function_setApprovalForAll(address owner,
address operator,
bool approved
) internalvirtual{
require(owner != operator, "ERC721: approve to caller");
_operatorApprovals[owner][operator] = approved;
emit ApprovalForAll(owner, operator, approved);
}
/**
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
* The call is not executed if the target address is not a 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_checkOnERC721Received(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) privatereturns (bool) {
if (to.isContract()) {
try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
return retval == IERC721Receiver.onERC721Received.selector;
} catch (bytesmemory reason) {
if (reason.length==0) {
revert("ERC721: transfer to non ERC721Receiver implementer");
} else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
} else {
returntrue;
}
}
/**
* @dev Hook that is called before any token transfer. This includes minting
* and burning.
*
* 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, ``from``'s `tokenId` will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/function_beforeTokenTransfer(addressfrom,
address to,
uint256 tokenId
) internalvirtual{}
}
Contract Source Code
File 6 of 12: IERC165.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)pragmasolidity ^0.8.0;/**
* @dev Interface of the ERC165 standard, as defined in the
* https://eips.ethereum.org/EIPS/eip-165[EIP].
*
* Implementers can declare support of contract interfaces, which can then be
* queried by others ({ERC165Checker}).
*
* For an implementation, see {ERC165}.
*/interfaceIERC165{
/**
* @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.
*/functionsupportsInterface(bytes4 interfaceId) externalviewreturns (bool);
}
Contract Source Code
File 7 of 12: IERC721.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)pragmasolidity ^0.8.0;import"../../utils/introspection/IERC165.sol";
/**
* @dev Required interface of an ERC721 compliant contract.
*/interfaceIERC721isIERC165{
/**
* @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
) 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.
*/functiontransferFrom(addressfrom,
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.
*/functionapprove(address to, uint256 tokenId) external;
/**
* @dev Returns the account approved for `tokenId` token.
*
* Requirements:
*
* - `tokenId` must exist.
*/functiongetApproved(uint256 tokenId) externalviewreturns (address operator);
/**
* @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 if the `operator` is allowed to manage all of the assets of `owner`.
*
* See {setApprovalForAll}
*/functionisApprovedForAll(address owner, address operator) externalviewreturns (bool);
/**
* @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,
bytescalldata data
) external;
}
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)pragmasolidity ^0.8.0;/**
* @title ERC721 token receiver interface
* @dev Interface for any contract that wants to support safeTransfers
* from ERC721 asset contracts.
*/interfaceIERC721Receiver{
/**
* @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
* by `operator` from `from`, this function is called.
*
* It must return its Solidity selector to confirm the token transfer.
* If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
*
* The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
*/functiononERC721Received(address operator,
addressfrom,
uint256 tokenId,
bytescalldata data
) externalreturns (bytes4);
}
Contract Source Code
File 10 of 12: MetaMint.sol
// SPDX-License-Identifier: UNLICENSEDpragmasolidity ^0.8.11;import"@openzeppelin/contracts/access/Ownable.sol";
import"@openzeppelin/contracts/token/ERC721/ERC721.sol";
import"@openzeppelin/contracts/utils/Strings.sol";
import"@openzeppelin/contracts/utils/Counters.sol";
/*
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNNNNNNNNNNNNNmmmmmNNNNNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNNNNNNNNNmmddmNNNmddmmNNNNNNNNNNNNNNNNNNN
NNNNNNNNNNNNNNmhhdNNNNmdddmNNNNmhhmNNNNNNNNNNNNNNN
NNNNNNNNNNmhs+///+syhdmNNNmmhyo/:::/shmNNNNNNNNNNN
NNNNNNNNNNy:::::/:://+shdho/:-------..oNNNNNNNNNNN
NNNNNNNNNNs::::::::::::::.............+NNNNNNNNNNN
NNNNNNNNNNs:::::::::::::-.....--......+NNNNNNNNNNN
NNNNNNNNNNs:::::://:///:--------......+NNNNNNNNNNN
NNNNNNNNNNs::::+///:////:::------:....+NNNNNNNNNNN
NNNNNNNNNNs::::mdyo/////:::-::+ydm:...+NNNNNNNNNNN
NNNNNNNNNNs::::NNNNhdyo+:/+ydhNNNN:...+NNNNNNNNNNN
NNNNNNNNNNs::::mNNNdNNNmymNNNdNNNm:...+NNNNNNNNNNN
NNNNNNNNNNs:::/mmmmhNNNNdNNNNhmmmm:...+NNNNNNNNNNN
NNNNNNNNNNd+//:NNNNhmmmmdNmmmhNNNN:.-/yNNNNNNNNNNN
NNNNNNNNNNNNmdymmNNdNNNNhmNNNdNNNmyhmNNNNNNNNNNNNN
NNNNNNNNNNNNNNNNNmmhmNNNdNNNNhmmmNNNNNNNNNNNNNNNNN
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*//// @title ERC-721 token for Meta Mint Software License./// @author @ItsCuzzocontractMetaMintisOwnable, ERC721{
usingStringsforuint;
usingCountersforCounters.Counter;
stringprivate _tokenURI;
stringprivate _contractURI;
Counters.Counter private _tokenIdCounter;
uintpublic maxSupply =300;
uintpublic tokenPrice =1.25ether;
uintpublic renewalPrice =0.3ether;
uintpublic maxTokensPerTx =3;
uintpublic gracePeriod =3days;
mapping(uint=>uint) public expiryTime;
mapping(uint=>bool) public isBanned;
structDutchAuction {
uint32 startTime;
uint72 startingPrice;
uint16 stepDuration;
uint72 reservePrice;
uint64 decrementAmount;
}
enumSaleStates {
PAUSED,
FCFS_MINT,
DUTCH_AUCTION
}
DutchAuction public auction;
SaleStates public saleState;
eventMinted(addressindexed _from, uint _amount);
eventRenewed(addressindexed _from, uint _tokenId);
eventRenewedBatch(addressindexed _from, uint[] _tokenIds);
eventBanned(addressindexed _from, uint _tokenId);
eventUnbanned(addressindexed _from, uint _tokenId);
constructor(stringmemory tokenURI_,
stringmemory contractURI_
) ERC721("Meta Mint", "MMAIO") {
_tokenURI = tokenURI_;
_contractURI = contractURI_;
}
/// @notice Function used to mint a token during the `DUTCH_AUCTION` sale.functionauctionMint() externalpayable{
require(tx.origin==msg.sender, "Caller should not be a contract.");
require(SaleStates.DUTCH_AUCTION == saleState, "Auction not active.");
require(auction.startTime <=block.timestamp, "Auction has not started.");
uint tokenIndex = _tokenIdCounter.current() +1;
require(maxSupply >= tokenIndex, "Minted tokens would exceed supply.");
require(msg.value>= getAuctionPrice(), "Incorrect Ether amount.");
_tokenIdCounter.increment();
_safeMint(msg.sender, tokenIndex);
expiryTime[tokenIndex] =block.timestamp+30days;
emit Minted(msg.sender, 1);
}
/// @notice Function used to mint tokens during the `FCFS_MINT` sale./// @param numTokens The desired number of tokens to mint.functionmint(uint numTokens) externalpayable{
require(tx.origin==msg.sender, "Caller should not be a contract.");
require(saleState == SaleStates.FCFS_MINT, "FCFS minting is not active.");
require(tokenPrice * numTokens ==msg.value, "Incorrect Ether amount.");
require(maxSupply >= _tokenIdCounter.current() + numTokens, "Minted tokens would exceed supply.");
require(maxTokensPerTx >= numTokens, "Token tx limit exceeded.");
for (uint i=0; i<numTokens; i++) {
_tokenIdCounter.increment();
uint tokenIndex = _tokenIdCounter.current();
_safeMint(msg.sender, tokenIndex);
expiryTime[tokenIndex] =block.timestamp+30days;
}
emit Minted(msg.sender, numTokens);
}
/// @notice Function that is used to extend/renew a tokens expiry date/// in increments of 30 days./// @param tokenId The token ID to extend/renew.functionrenewToken(uint tokenId) publicpayable{
require(_exists(tokenId), "Token does not exist.");
require(ownerOf(tokenId) ==msg.sender, "Caller does not own token.");
require(!isBanned[tokenId], "Token is banned.");
require(msg.value== renewalPrice, "Incorrect Ether amount.");
uint _currentexpiryTime = expiryTime[tokenId];
if (block.timestamp> _currentexpiryTime) {
expiryTime[tokenId] =block.timestamp+30days;
} else {
expiryTime[tokenId] +=30days;
}
emit Renewed(msg.sender, tokenId);
}
/// @notice Function that is used to extend/renew multiple tokens expiry date/// in increments of 30 days./// @param tokenIds The token IDs to extend/renew.functionbatchRenewToken(uint[] calldata tokenIds) publicpayable{
require(tokenIds.length>=2, "Invalid array length.");
require(renewalPrice * tokenIds.length==msg.value, "Incorrect Ether amount.");
for (uint i=0; i<tokenIds.length; i++) {
require(_exists(tokenIds[i]), "Token does not exist.");
require(ownerOf(tokenIds[i]) ==msg.sender, "Caller does not own token.");
require(!isBanned[tokenIds[i]], "Token is banned.");
uint _currentexpiryTime = expiryTime[tokenIds[i]];
if (block.timestamp> _currentexpiryTime) {
expiryTime[tokenIds[i]] =block.timestamp+30days;
} else {
expiryTime[tokenIds[i]] +=30days;
}
}
emit RenewedBatch(msg.sender, tokenIds);
}
/// @notice Function that is used to mint a token free of charge, only/// callable by the owner.functionownerMint(address receiver) publiconlyOwner{
uint tokenIndex = _tokenIdCounter.current() +1;
require(maxSupply >= tokenIndex, "Minted tokens would exceed supply.");
_tokenIdCounter.increment();
_safeMint(receiver, tokenIndex);
expiryTime[tokenIndex] =block.timestamp+30days;
emit Minted(msg.sender, 1);
}
/// @notice Function that is used to extend/renew a tokens expiry date/// in increments of 30 days free of charge, only callable by the owner./// @param tokenId The token ID to extend/renew.functionownerRenewToken(uint tokenId) publiconlyOwner{
require(_exists(tokenId), "Token does not exist.");
uint _currentexpiryTime = expiryTime[tokenId];
if (block.timestamp> _currentexpiryTime) {
expiryTime[tokenId] =block.timestamp+30days;
} else {
expiryTime[tokenId] +=30days;
}
emit Renewed(msg.sender, tokenId);
}
/// @notice Function that is used to extend/renew multiple tokens expiry date/// in increments of 30 days free of charge, only callable by the owner./// @param tokenIds The token IDs to extend/renew.functionownerBatchRenewToken(uint[] calldata tokenIds) publiconlyOwner{
require(tokenIds.length>=2, "Invalid array length.");
for (uint i=0; i<tokenIds.length; i++) {
require(_exists(tokenIds[i]), "Token does not exist.");
uint _currentexpiryTime = expiryTime[tokenIds[i]];
if (block.timestamp> _currentexpiryTime) {
expiryTime[tokenIds[i]] =block.timestamp+30days;
} else {
expiryTime[tokenIds[i]] +=30days;
}
}
emit RenewedBatch(msg.sender, tokenIds);
}
/// @notice Function used to get the current price of a token during the/// dutch auction./// @dev This function should be polled externally to determine how much/// Ether a participant should send./// @return Returns a uint indicating the current price of the token in/// wei.functiongetAuctionPrice() publicviewreturns (uint72) {
if (saleState != SaleStates.DUTCH_AUCTION || auction.startTime >=block.timestamp) {
return auction.startingPrice;
}
uint72 decrements = (uint72(block.timestamp) - auction.startTime) / auction.stepDuration;
if (decrements * auction.decrementAmount >= auction.startingPrice) {
return auction.reservePrice;
}
if (auction.startingPrice - decrements * auction.decrementAmount < auction.reservePrice) {
return auction.reservePrice;
}
return auction.startingPrice - decrements * auction.decrementAmount;
}
/// @notice Function used to define the dutch auction settings./// @param _startTime Starting time for the auction in seconds./// @param _startingPrice Starting price for the auction in wei./// @param _stepDuration Time between each price decrease, in seconds./// @param _reservePrice Reserve price for the auction in wei./// @param _decrementAmount Amount that price decreases every step, in wei./// @dev Reasoning for doing one function for all updates is that once the/// auction is configured once, it shouldn't need changing until afterwards.functionsetAuctionBulk(uint32 _startTime, uint72 _startingPrice, uint16 _stepDuration, uint72 _reservePrice, uint64 _decrementAmount
) externalonlyOwner{
require(_startTime >block.timestamp, "Invalid start time.");
require(_startingPrice > _reservePrice, "Initial price must exceed reserve.");
auction.startTime = _startTime;
auction.startingPrice = _startingPrice;
auction.stepDuration = _stepDuration;
auction.reservePrice = _reservePrice;
auction.decrementAmount = _decrementAmount;
}
/// @notice Function used to set the dutch auction start time./// @param _startTime A UNIX epoch, in seconds, of the intended start time./// @dev Pssst, https://www.epochconverter.com/functionsetAuctionStartTime(uint32 _startTime) externalonlyOwner{
require(_startTime >block.timestamp, "Invalid start time.");
auction.startTime = _startTime;
}
/// @notice Function used to set the starting price of the dutch auction./// @param _startingPrice uint value in wei representing the starting price.functionsetAuctionStartingPrice(uint72 _startingPrice) externalonlyOwner{
require(auction.startingPrice != _startingPrice, "Price has not changed.");
auction.startingPrice = _startingPrice;
}
/// @notice Function used to set the step time during the dutch auction./// @param _stepDuration uint value is seconds representing how frequently the/// price will drop. E.g. Input of 120 is equivalent to 2 minutes.functionsetAuctionStepDuration(uint16 _stepDuration) externalonlyOwner{
require(auction.stepDuration != _stepDuration, "Duration has not changed.");
auction.stepDuration = _stepDuration;
}
/// @notice Function used to set the dutch auction reserve price./// @param _reservePrice Represents the reserve price in units of wei.functionsetAuctionReservePrice(uint72 _reservePrice) externalonlyOwner{
require(auction.reservePrice != _reservePrice, "Price has not changed.");
auction.reservePrice = _reservePrice;
}
/// @notice Function used to set the dutch auction decrement amount./// @param _decrementAmount uint value representing how much the price/// will drop each step. E.g. 25000000000000000 is 0.025 Ether.functionsetAuctionDecrementAmount(uint64 _decrementAmount) externalonlyOwner{
require(auction.decrementAmount != _decrementAmount, "Decrement has not changed.");
auction.decrementAmount = _decrementAmount;
}
/// @notice Function that is used to update the `renewalPrice` variable,/// only callable by the owner./// @param newRenewalPrice The new renewal price in units of wei. E.g./// 500000000000000000 is 0.50 Ether.functionupdateRenewalPrice(uint newRenewalPrice) externalonlyOwner{
require(renewalPrice != newRenewalPrice, "Price has not changed.");
renewalPrice = newRenewalPrice;
}
/// @notice Function that is used to update the `tokenPrice` variable,/// only callable by the owner./// @param newTokenPrice The new initial token price in units of wei. E.g./// 2000000000000000000 is 2 Ether.functionupdateTokenPrice(uint newTokenPrice) externalonlyOwner{
require(tokenPrice != newTokenPrice, "Price has not changed.");
tokenPrice = newTokenPrice;
}
/// @notice Function that is used to update the `maxTokensPerTx` variable,/// only callable by the owner./// @param newMaxTokensPerTx The new maximum amount of tokens a user can/// mint in a single tx.functionupdateMaxTokensPerTx(uint newMaxTokensPerTx) externalonlyOwner{
require(maxTokensPerTx != newMaxTokensPerTx, "Max tokens has not changed.");
maxTokensPerTx = newMaxTokensPerTx;
}
/// @notice Function that is used to update the `GRACE_PERIOD` variable,/// only callable by the owner./// @param newGracePeriod The new grace period in units of seconds in wei. /// E.g. 2592000 is 30 days./// @dev Grace period should be atleast 1 day, uint value of 86400.functionupdateGracePeriod(uint newGracePeriod) externalonlyOwner{
require(gracePeriod != newGracePeriod, "Duration has not changed.");
require(newGracePeriod %1days==0, "Must provide 1 day increments.");
gracePeriod = newGracePeriod;
}
/// @notice Function used to set a new `saleState` value./// @param newSaleState The newly desired sale state./// @dev 0 = PAUSED, 1 = FCFS_MINT, 2 = DUTCH_AUCTION.functionsetSaleState(uint newSaleState) externalonlyOwner{
require(uint(SaleStates.DUTCH_AUCTION) >= newSaleState, "Invalid sale state.");
saleState = SaleStates(newSaleState);
}
/// @notice Function that is used to authenticate a user./// @param tokenId The desired token owned by a user./// @return Returns a bool value determining if authentication was/// was successful. `true` is successful, `false` if otherwise.functionauthenticateUser(uint tokenId) publicviewreturns (bool) {
require(_exists(tokenId), "Token does not exist.");
require(!isBanned[tokenId], "Token is banned.");
require(expiryTime[tokenId] + gracePeriod >block.timestamp, "Token has expired. Please renew!");
returnmsg.sender== ownerOf(tokenId) ? true : false;
}
/// @notice Function used to increment the `maxSupply` value./// @param numTokens The amount of tokens to add to `maxSupply`.functionaddTokens(uint numTokens) externalonlyOwner{
maxSupply += numTokens;
}
/// @notice Function used to decrement the `maxSupply` value./// @param numTokens The amount of tokens to remove from `maxSupply`.functionremoveTokens(uint numTokens) externalonlyOwner{
require(maxSupply - numTokens >= _tokenIdCounter.current(), "Supply cannot fall below minted tokens.");
maxSupply -= numTokens;
}
/// @notice Function used to ban a token, only callable by the owner./// @param tokenId The token ID to ban.functionbanToken(uint tokenId) externalonlyOwner{
require(!isBanned[tokenId], "Token already banned.");
expiryTime[tokenId] =block.timestamp;
isBanned[tokenId] =true;
emit Banned(msg.sender, tokenId);
}
/// @notice Function used to unban a token, only callable by the owner./// @param tokenId The token ID to unban.functionunbanToken(uint tokenId) externalonlyOwner{
require(isBanned[tokenId], "Token is not banned.");
isBanned[tokenId] =false;
emit Unbanned(msg.sender, tokenId);
}
/// @notice Function that is used to get the current `_contractURI` value./// @return Returns a string value of `_contractURI`.functioncontractURI() publicviewreturns (stringmemory) {
return _contractURI;
}
/// @notice Function that is used to update the `_contractURI` value, only/// callable by the owner./// @param contractURI_ A string value to replace the current 'contractURI_'.functionsetContractURI(stringcalldata contractURI_) externalonlyOwner{
_contractURI = contractURI_;
}
/// @notice Function that is used to get the `_tokenURI` for `tokenId`./// @param tokenId The `tokenId` to get the `_tokenURI` for./// @return Returns a string representing the `_tokenURI` for `tokenId`.functiontokenURI(uint tokenId) publicviewoverridereturns (stringmemory) {
require(_exists(tokenId), "Token does not exist.");
returnstring(abi.encodePacked(_tokenURI, tokenId.toString()));
}
/// @notice Function that is used to update the `_tokenURI` value, only /// callable by the owner./// @param tokenURI_ A string value to replace the current `_tokenURI` value.functionsetTokenURI(stringcalldata tokenURI_) externalonlyOwner{
_tokenURI = tokenURI_;
}
/// @notice Function used to get the total number of minted tokens.functiontotalSupply() publicviewreturns (uint) {
return _tokenIdCounter.current();
}
/// @notice Function that is used to withdraw the total balance of the/// contract, only callable by the owner.functionwithdrawBalance() publiconlyOwner{
payable(msg.sender).transfer(address(this).balance);
}
/// @notice Function used to get the tokens owned by a provided address./// @param _address The specified address to perform a lookup for./// @dev DO NOT CALL THIS FUNCTION ON-CHAIN.functiongetTokensOwnedByAddress(address _address) externalviewreturns (uint[] memory) {
uint tokenBalance = balanceOf(_address);
if (tokenBalance ==0) {
returnnewuint[](0);
}
uint[] memory tokensOwned =newuint[](tokenBalance);
uint resultIndex =0;
for (uint i=1; i<=_tokenIdCounter.current(); i++) {
if (ownerOf(i) == _address) {
tokensOwned[resultIndex] = i;
resultIndex++;
}
}
return tokensOwned;
}
/// @notice Function used to get the tokens currently within the grace period./// @dev DO NOT CALL THIS FUNCTION ON-CHAIN.functiongetTokensInGracePeriod() externalviewreturns (uint[] memory) {
uint tokenSupply = _tokenIdCounter.current();
uint numTokens =0;
for (uint i=1; i<=tokenSupply; i++) {
if (block.timestamp> expiryTime[i] && expiryTime[i] + gracePeriod >block.timestamp) {
if (!isBanned[i]) {
numTokens++;
}
}
}
uint[] memory graceTokens =newuint[](numTokens);
uint index =0;
for (uint i=1; i<=tokenSupply; i++) {
if (block.timestamp> expiryTime[i] && expiryTime[i] + gracePeriod >block.timestamp) {
if (!isBanned[i]) {
graceTokens[index] = i;
index++;
}
}
}
return graceTokens;
}
/// @notice Function that is used to safely transfer a token from one owner to another.functionsafeTransferFrom(addressfrom,
address to,
uint256 tokenId,
bytesmemory _data
) publicvirtualoverride{
require(_isApprovedOrOwner(_msgSender(), tokenId), "Transfer caller is not owner nor approved.");
if (owner() !=msg.sender) {
require(!isBanned[tokenId], "Token is banned.");
require(expiryTime[tokenId] >block.timestamp, "Token has expired.");
}
_safeTransfer(from, to, tokenId, _data);
}
/// @notice Function that is used to transfer a token from one owner to another.functiontransferFrom(addressfrom,
address to,
uint256 tokenId
) publicvirtualoverride{
require(_isApprovedOrOwner(_msgSender(), tokenId), "Transfer caller is not owner nor approved.");
if (owner() !=msg.sender) {
require(!isBanned[tokenId], "Token is banned.");
require(expiryTime[tokenId] >block.timestamp, "Token has expired.");
}
_transfer(from, to, tokenId);
}
}
Contract Source Code
File 11 of 12: Ownable.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (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 Returns the address of the current owner.
*/functionowner() publicviewvirtualreturns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/modifieronlyOwner() {
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 12 of 12: Strings.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)pragmasolidity ^0.8.0;/**
* @dev String operations.
*/libraryStrings{
bytes16privateconstant _HEX_SYMBOLS ="0123456789abcdef";
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/functiontoString(uint256 value) internalpurereturns (stringmemory) {
// Inspired by OraclizeAPI's implementation - MIT licence// https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.solif (value ==0) {
return"0";
}
uint256 temp = value;
uint256 digits;
while (temp !=0) {
digits++;
temp /=10;
}
bytesmemory buffer =newbytes(digits);
while (value !=0) {
digits -=1;
buffer[digits] =bytes1(uint8(48+uint256(value %10)));
value /=10;
}
returnstring(buffer);
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
*/functiontoHexString(uint256 value) internalpurereturns (stringmemory) {
if (value ==0) {
return"0x00";
}
uint256 temp = value;
uint256 length =0;
while (temp !=0) {
length++;
temp >>=8;
}
return toHexString(value, length);
}
/**
* @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] = _HEX_SYMBOLS[value &0xf];
value >>=4;
}
require(value ==0, "Strings: hex length insufficient");
returnstring(buffer);
}
}