17.77
($1.09%)
| 1 Gwei
// SPDX-License-Identifier: MIT pragma solidity ^0.8.4; // Sources flattened with hardhat v2.9.1 https://hardhat.org /** * @dev Provides information about the current execution context, including the * sender of the transaction and its data. While these are generally available * via msg.sender and msg.data, they should not be accessed in such a direct * manner, since when dealing with meta-transactions the account sending and * paying for execution may not be the actual sender (as far as an application * is concerned). * * This contract is only required for intermediate, library-like contracts. */ abstract contract Context { function _msgSender() internal view virtual returns (address) { return msg.sender; } function _msgData() internal view virtual returns (bytes calldata) { return msg.data; } } /** * @dev Contract module which provides a basic access control mechanism, where * there is an account (an owner) that can be granted exclusive access to * specific functions. * * By default, the owner account will be the one that deploys the contract. This * can later be changed with {transferOwnership}. * * This module is used through inheritance. It will make available the modifier * `onlyOwner`, which can be applied to your functions to restrict their use to * the owner. */ abstract contract Ownable is Context { address private _owner; event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); /** * @dev Initializes the contract setting the deployer as the initial owner. */ constructor() { _transferOwnership(_msgSender()); } /** * @dev Returns the address of the current owner. */ function owner() public view virtual returns (address) { return _owner; } /** * @dev Throws if called by any account other than the owner. */ modifier onlyOwner() { require(owner() == _msgSender(), "Ownable: caller is not the owner"); _; } /** * @dev Leaves the contract without owner. It will not be possible to call * `onlyOwner` functions anymore. Can only be called by the current owner. * * NOTE: Renouncing ownership will leave the contract without an owner, * thereby removing any functionality that is only available to the owner. */ function renounceOwnership() public virtual onlyOwner { _transferOwnership(address(0)); } /** * @dev Transfers ownership of the contract to a new account (`newOwner`). * Can only be called by the current owner. */ function transferOwnership(address newOwner) public virtual onlyOwner { require(newOwner != address(0), "Ownable: new owner is the zero address"); _transferOwnership(newOwner); } /** * @dev Transfers ownership of the contract to a new account (`newOwner`). * Internal function without access restriction. */ function _transferOwnership(address newOwner) internal virtual { address oldOwner = _owner; _owner = newOwner; emit OwnershipTransferred(oldOwner, newOwner); } } /** * @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]. */ abstract contract ReentrancyGuard { // 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. uint256 private constant _NOT_ENTERED = 1; uint256 private constant _ENTERED = 2; uint256 private _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. */ modifier nonReentrant() { // On the first call to nonReentrant, _notEntered will be true require(_status != _ENTERED, "ReentrancyGuard: reentrant call"); // Any calls to nonReentrant after this point will fail _status = _ENTERED; _; // By storing the original value once again, a refund is triggered (see // https://eips.ethereum.org/EIPS/eip-2200) _status = _NOT_ENTERED; } } /** * @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}. */ interface IERC165 { /** * @dev Returns true if this contract implements the interface defined by * `interfaceId`. See the corresponding * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section] * to learn more about how these ids are created. * * This function call must use less than 30 000 gas. */ function supportsInterface(bytes4 interfaceId) external view returns (bool); } /** * @dev Required interface of an ERC721 compliant contract. */ interface IERC721 is IERC165 { /** * @dev Emitted when `tokenId` token is transferred from `from` to `to`. */ event Transfer(address indexed from, address indexed to, uint256 indexed tokenId); /** * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token. */ event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId); /** * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets. */ event ApprovalForAll(address indexed owner, address indexed operator, bool approved); /** * @dev Returns the number of tokens in ``owner``'s account. */ function balanceOf(address owner) external view returns (uint256 balance); /** * @dev Returns the owner of the `tokenId` token. * * Requirements: * * - `tokenId` must exist. */ function ownerOf(uint256 tokenId) external view returns (address owner); /** * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients * are aware of the ERC721 protocol to prevent tokens from being forever locked. * * Requirements: * * - `from` cannot be the zero address. * - `to` cannot be the zero address. * - `tokenId` token must exist and be owned by `from`. * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}. * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. * * Emits a {Transfer} event. */ function safeTransferFrom( address from, address to, uint256 tokenId ) external; /** * @dev Transfers `tokenId` token from `from` to `to`. * * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible. * * Requirements: * * - `from` cannot be the zero address. * - `to` cannot be the zero address. * - `tokenId` token must be owned by `from`. * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. * * Emits a {Transfer} event. */ function transferFrom( address from, address to, uint256 tokenId ) external; /** * @dev Gives permission to `to` to transfer `tokenId` token to another account. * The approval is cleared when the token is transferred. * * Only a single account can be approved at a time, so approving the zero address clears previous approvals. * * Requirements: * * - The caller must own the token or be an approved operator. * - `tokenId` must exist. * * Emits an {Approval} event. */ function approve(address to, uint256 tokenId) external; /** * @dev Returns the account approved for `tokenId` token. * * Requirements: * * - `tokenId` must exist. */ function getApproved(uint256 tokenId) external view returns (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. */ function setApprovalForAll(address operator, bool _approved) external; /** * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`. * * See {setApprovalForAll} */ function isApprovedForAll(address owner, address operator) external view returns (bool); /** * @dev Safely transfers `tokenId` token from `from` to `to`. * * Requirements: * * - `from` cannot be the zero address. * - `to` cannot be the zero address. * - `tokenId` token must exist and be owned by `from`. * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}. * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer. * * Emits a {Transfer} event. */ function safeTransferFrom( address from, address to, uint256 tokenId, bytes calldata data ) external; } /** * @dev Library for managing * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive * types. * * Sets have the following properties: * * - Elements are added, removed, and checked for existence in constant time * (O(1)). * - Elements are enumerated in O(n). No guarantees are made on the ordering. * * ``` * contract Example { * // Add the library methods * using EnumerableSet for EnumerableSet.AddressSet; * * // Declare a set state variable * EnumerableSet.AddressSet private mySet; * } * ``` * * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`) * and `uint256` (`UintSet`) are supported. */ library EnumerableSet { // To implement this library for multiple types with as little code // repetition as possible, we write it in terms of a generic Set type with // bytes32 values. // The Set implementation uses private functions, and user-facing // implementations (such as AddressSet) are just wrappers around the // underlying Set. // This means that we can only create new EnumerableSets for types that fit // in bytes32. struct Set { // Storage of set values bytes32[] _values; // Position of the value in the `values` array, plus 1 because index 0 // means a value is not in the set. mapping(bytes32 => uint256) _indexes; } /** * @dev Add a value to a set. O(1). * * Returns true if the value was added to the set, that is if it was not * already present. */ function _add(Set storage set, bytes32 value) private returns (bool) { if (!_contains(set, value)) { set._values.push(value); // The value is stored at length-1, but we add 1 to all indexes // and use 0 as a sentinel value set._indexes[value] = set._values.length; return true; } else { return false; } } /** * @dev Removes a value from a set. O(1). * * Returns true if the value was removed from the set, that is if it was * present. */ function _remove(Set storage set, bytes32 value) private returns (bool) { // We read and store the value's index to prevent multiple reads from the same storage slot uint256 valueIndex = set._indexes[value]; if (valueIndex != 0) { // Equivalent to contains(set, value) // To delete an element from the _values array in O(1), we swap the element to delete with the last one in // the array, and then remove the last element (sometimes called as 'swap and pop'). // This modifies the order of the array, as noted in {at}. uint256 toDeleteIndex = valueIndex - 1; uint256 lastIndex = set._values.length - 1; if (lastIndex != toDeleteIndex) { bytes32 lastvalue = set._values[lastIndex]; // Move the last value to the index where the value to delete is set._values[toDeleteIndex] = lastvalue; // Update the index for the moved value set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex } // Delete the slot where the moved value was stored set._values.pop(); // Delete the index for the deleted slot delete set._indexes[value]; return true; } else { return false; } } /** * @dev Returns true if the value is in the set. O(1). */ function _contains(Set storage set, bytes32 value) private view returns (bool) { return set._indexes[value] != 0; } /** * @dev Returns the number of values on the set. O(1). */ function _length(Set storage set) private view returns (uint256) { return set._values.length; } /** * @dev Returns the value stored at position `index` in the set. O(1). * * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function _at(Set storage set, uint256 index) private view returns (bytes32) { return set._values[index]; } /** * @dev Return the entire set in an array * * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that * this function has an unbounded cost, and using it as part of a state-changing function may render the function * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block. */ function _values(Set storage set) private view returns (bytes32[] memory) { return set._values; } // Bytes32Set struct Bytes32Set { Set _inner; } /** * @dev Add a value to a set. O(1). * * Returns true if the value was added to the set, that is if it was not * already present. */ function add(Bytes32Set storage set, bytes32 value) internal returns (bool) { return _add(set._inner, value); } /** * @dev Removes a value from a set. O(1). * * Returns true if the value was removed from the set, that is if it was * present. */ function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) { return _remove(set._inner, value); } /** * @dev Returns true if the value is in the set. O(1). */ function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) { return _contains(set._inner, value); } /** * @dev Returns the number of values in the set. O(1). */ function length(Bytes32Set storage set) internal view returns (uint256) { return _length(set._inner); } /** * @dev Returns the value stored at position `index` in the set. O(1). * * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) { return _at(set._inner, index); } /** * @dev Return the entire set in an array * * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that * this function has an unbounded cost, and using it as part of a state-changing function may render the function * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block. */ function values(Bytes32Set storage set) internal view returns (bytes32[] memory) { return _values(set._inner); } // AddressSet struct AddressSet { Set _inner; } /** * @dev Add a value to a set. O(1). * * Returns true if the value was added to the set, that is if it was not * already present. */ function add(AddressSet storage set, address value) internal returns (bool) { return _add(set._inner, bytes32(uint256(uint160(value)))); } /** * @dev Removes a value from a set. O(1). * * Returns true if the value was removed from the set, that is if it was * present. */ function remove(AddressSet storage set, address value) internal returns (bool) { return _remove(set._inner, bytes32(uint256(uint160(value)))); } /** * @dev Returns true if the value is in the set. O(1). */ function contains(AddressSet storage set, address value) internal view returns (bool) { return _contains(set._inner, bytes32(uint256(uint160(value)))); } /** * @dev Returns the number of values in the set. O(1). */ function length(AddressSet storage set) internal view returns (uint256) { return _length(set._inner); } /** * @dev Returns the value stored at position `index` in the set. O(1). * * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function at(AddressSet storage set, uint256 index) internal view returns (address) { return address(uint160(uint256(_at(set._inner, index)))); } /** * @dev Return the entire set in an array * * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that * this function has an unbounded cost, and using it as part of a state-changing function may render the function * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block. */ function values(AddressSet storage set) internal view returns (address[] memory) { bytes32[] memory store = _values(set._inner); address[] memory result; assembly { result := store } return result; } // UintSet struct UintSet { Set _inner; } /** * @dev Add a value to a set. O(1). * * Returns true if the value was added to the set, that is if it was not * already present. */ function add(UintSet storage set, uint256 value) internal returns (bool) { return _add(set._inner, bytes32(value)); } /** * @dev Removes a value from a set. O(1). * * Returns true if the value was removed from the set, that is if it was * present. */ function remove(UintSet storage set, uint256 value) internal returns (bool) { return _remove(set._inner, bytes32(value)); } /** * @dev Returns true if the value is in the set. O(1). */ function contains(UintSet storage set, uint256 value) internal view returns (bool) { return _contains(set._inner, bytes32(value)); } /** * @dev Returns the number of values on the set. O(1). */ function length(UintSet storage set) internal view returns (uint256) { return _length(set._inner); } /** * @dev Returns the value stored at position `index` in the set. O(1). * * Note that there are no guarantees on the ordering of values inside the * array, and it may change when more values are added or removed. * * Requirements: * * - `index` must be strictly less than {length}. */ function at(UintSet storage set, uint256 index) internal view returns (uint256) { return uint256(_at(set._inner, index)); } /** * @dev Return the entire set in an array * * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that * this function has an unbounded cost, and using it as part of a state-changing function may render the function * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block. */ function values(UintSet storage set) internal view returns (uint256[] memory) { bytes32[] memory store = _values(set._inner); uint256[] memory result; assembly { result := store } return result; } } /** * @title ERC721 token receiver interface * @dev Interface for any contract that wants to support safeTransfers * from ERC721 asset contracts. */ interface IERC721Receiver { /** * @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`. */ function onERC721Received( address operator, address from, uint256 tokenId, bytes calldata data ) external returns (bytes4); } // 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. */ library SafeMath { /** * @dev Returns the addition of two unsigned integers, with an overflow flag. * * _Available since v3.4._ */ function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) { unchecked { uint256 c = a + b; if (c < a) return (false, 0); return (true, c); } } /** * @dev Returns the substraction of two unsigned integers, with an overflow flag. * * _Available since v3.4._ */ function trySub(uint256 a, uint256 b) internal pure returns (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._ */ function tryMul(uint256 a, uint256 b) internal pure returns (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/522 if (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._ */ function tryDiv(uint256 a, uint256 b) internal pure returns (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._ */ function tryMod(uint256 a, uint256 b) internal pure returns (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. */ function add(uint256 a, uint256 b) internal pure returns (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. */ function sub(uint256 a, uint256 b) internal pure returns (uint256) { return a - b; } /** * @dev Returns the multiplication of two unsigned integers, reverting on * overflow. * * Counterpart to Solidity's `*` operator. * * Requirements: * * - Multiplication cannot overflow. */ function mul(uint256 a, uint256 b) internal pure returns (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. */ function div(uint256 a, uint256 b) internal pure returns (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. */ function mod(uint256 a, uint256 b) internal pure returns (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. */ function sub( uint256 a, uint256 b, string memory errorMessage ) internal pure returns (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. */ function div( uint256 a, uint256 b, string memory errorMessage ) internal pure returns (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. */ function mod( uint256 a, uint256 b, string memory errorMessage ) internal pure returns (uint256) { unchecked { require(b > 0, errorMessage); return a % b; } } } /** * @title ERC-721 Non-Fungible Token Standard, optional metadata extension * @dev See https://eips.ethereum.org/EIPS/eip-721 */ interface IERC721Metadata is IERC721 { /** * @dev Returns the token collection name. */ function name() external view returns (string memory); /** * @dev Returns the token collection symbol. */ function symbol() external view returns (string memory); /** * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token. */ function tokenURI(uint256 tokenId) external view returns (string memory); } /** * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension * @dev See https://eips.ethereum.org/EIPS/eip-721 */ interface IERC721Enumerable is IERC721 { /** * @dev Returns the total amount of tokens stored by the contract. */ function totalSupply() external view returns (uint256); /** * @dev Returns a token ID owned by `owner` at a given `index` of its token list. * Use along with {balanceOf} to enumerate all of ``owner``'s tokens. */ function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256); /** * @dev Returns a token ID at a given `index` of all the tokens stored by the contract. * Use along with {totalSupply} to enumerate all tokens. */ function tokenByIndex(uint256 index) external view returns (uint256); } /** * @dev String operations. */ library Strings { bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef"; /** * @dev Converts a `uint256` to its ASCII `string` decimal representation. */ function toString(uint256 value) internal pure returns (string memory) { // Inspired by OraclizeAPI's implementation - MIT licence // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol if (value == 0) { return "0"; } uint256 temp = value; uint256 digits; while (temp != 0) { digits++; temp /= 10; } bytes memory buffer = new bytes(digits); while (value != 0) { digits -= 1; buffer[digits] = bytes1(uint8(48 + uint256(value % 10))); value /= 10; } return string(buffer); } /** * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation. */ function toHexString(uint256 value) internal pure returns (string memory) { 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. */ function toHexString(uint256 value, uint256 length) internal pure returns (string memory) { bytes memory buffer = new bytes(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"); return string(buffer); } } contract ClassicHomelessSociety is Ownable, ReentrancyGuard, IERC721, IERC721Metadata, IERC721Enumerable { using SafeMath for uint256; using Strings for uint256; using EnumerableSet for EnumerableSet.UintSet; string private constant _name = "ClassicHomelessSociety"; string private constant _symbol = "CHS"; string private _baseURI; uint256 internal totalMinted = 0; uint256 public MAX_SUPPLY = 5000; address payable internal immutable _wallet1; address payable internal immutable _wallet2; address payable internal immutable _wallet3; uint256[2] private mintingLevelPrices = [1 ether, 2 ether]; //Service: bool internal isReentrancyLock = false; address internal addressZero = address(0); // Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))` // which can be also obtained as `IERC721Receiver(0).onERC721Received.selector` bytes4 internal constant MAGIC_ON_ERC721_RECEIVED = 0x150b7a02; uint internal constant maxPerTx = 20; // Used for random index assignment mapping(uint256 => uint256) private tokenMatrix; uint256 internal startFrom; uint256 internal nonce = 0; // Supported interfaces mapping(bytes4 => bool) internal supportedInterfaces; // storage mapping (uint256 => address) internal tokenToOwner; mapping (address => EnumerableSet.UintSet) internal ownerToTokensSet; mapping (uint256 => address) internal tokenToApproval; mapping (address => mapping (address => bool)) internal ownerToOperators; bool public isMintingEnabled = false; constructor(string memory baseURI_, address payable wallet1, address payable wallet3, address payable wallet2) { supportedInterfaces[0x01ffc9a7] = true; // ERC165 supportedInterfaces[0x80ac58cd] = true; // ERC721 supportedInterfaces[0x780e9d63] = true; // ERC721 Enumerable supportedInterfaces[0x5b5e139f] = true; // ERC721 Metadata _setBaseURI(baseURI_); _wallet1 = wallet1; _wallet2 = wallet2; _wallet3 = wallet3; } /*************************************************************************** */ // IERC721Metadata: function name() external pure override returns (string memory) { return _name; } function symbol() external pure override returns (string memory) { return _symbol; } function tokenURI(uint256 _tokenId) external view override returns (string memory) { require(_exists(_tokenId), "ERC721Metadata: URI query for nonexistent token"); return string(abi.encodePacked(_baseURI, _tokenId.toString(), '.json')); } /*************************************************************************** */ // Enumerable: function totalSupply() public view override returns(uint256) { return totalMinted; } function tokenByIndex(uint256 _index) external view override returns (uint256) { require(_index >= 0 && _index < MAX_SUPPLY); return _index; } function tokenOfOwnerByIndex(address _owner, uint256 _index) external view override returns (uint256 _tokenId) { require(_index < ownerToTokensSet[_owner].values().length); return ownerToTokensSet[_owner].values()[_index]; } function getNotMintedAmount() external view returns(uint256) { return MAX_SUPPLY - totalMinted; } /*************************************************************************** */ // IERC165: function supportsInterface(bytes4 _interfaceID) external view override returns (bool) { return supportedInterfaces[_interfaceID]; } /*************************************************************************** */ // ERC-721: function balanceOf(address _owner) external view override returns (uint256) { return ownerToTokensSet[_owner].values().length; } function ownerOf(uint256 _tokenId) external view override returns (address) { return tokenToOwner[_tokenId]; } function safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes calldata _data) external override { _safeTransferFrom(_from, _to, _tokenId, _data); } function safeTransferFrom(address _from, address _to, uint256 _tokenId) external override { _safeTransferFrom(_from, _to, _tokenId, ""); } function transferFrom(address _from, address _to, uint256 _tokenId) external override transferApproved(_tokenId) validTokenId(_tokenId) notZeroAddress(_to) { _transfer(_from, _to, _tokenId); } function approve(address _approved, uint256 _tokenId) external override validTokenId(_tokenId) canOperate(_tokenId) { address tokenOwner = tokenToOwner[_tokenId]; if (_approved != tokenOwner) { tokenToApproval[_tokenId] = _approved; emit Approval(tokenOwner, _approved, _tokenId); } } function setApprovalForAll(address _operator, bool _approved) external override { ownerToOperators[msg.sender][_operator] = _approved; emit ApprovalForAll(msg.sender, _operator, _approved); } function getApproved(uint256 _tokenId) external view override validTokenId(_tokenId) returns (address) { return tokenToApproval[_tokenId]; } function isApprovedForAll(address _owner, address _operator) external view override returns (bool) { return ownerToOperators[_owner][_operator]; } function _exists(uint256 tokenId) internal view returns (bool) { return tokenToOwner[tokenId] != address(0); } /*************************************************************************** */ function getUserTokens(address _user) external view returns (uint256[] memory) { return ownerToTokensSet[_user].values(); } /*************************************************************************** */ // Mint: function getMintPrice(uint256 amount) public view returns (uint256 price) { uint256 currentSupply = totalSupply(); require(currentSupply + amount <= MAX_SUPPLY, "sale already ended"); for (uint256 i = 1; i <= amount; i++) { if(currentSupply + i > maxPerTx) { price += mintingLevelPrices[1]; } else { price += mintingLevelPrices[0]; } } } function mint(uint256 amount) external payable nonReentrant mintingEnabled { require(amount >= 1 && amount <= maxPerTx, "amountLimit"); require((totalMinted + amount) <= MAX_SUPPLY, "exceedsMaxSupply"); uint256 nftPrice = getMintPrice(amount); require(msg.value >= nftPrice, "notEnough"); if (msg.value > nftPrice) { (bool send, ) = msg.sender.call{ value: msg.value - nftPrice }(""); require(send, "refund"); } uint256 comissionOne = nftPrice * 30 / 100; (bool sentOne, ) = _wallet1.call{ value: comissionOne }(""); require(sentOne, "comissionOne failed"); uint256 comissionTwo = (nftPrice - comissionOne) / 2; (bool sentTwo, ) = _wallet2.call{ value: comissionTwo }(""); require(sentTwo, "comissionTwo failed"); (bool sentThree, ) = _wallet3.call{ value: comissionTwo }(""); require(sentThree, "comissionThree failed"); for (uint i = 0; i < amount; i++) { _mint(msg.sender); } } /*************************************************************************** */ /*************************************************************************** */ // Internal functions: function _mint(address _to) internal notZeroAddress(_to) returns (uint256 _mintedTokenId) { require(totalMinted < MAX_SUPPLY, "allMinted"); uint randomId = generateRandom(); totalMinted++; _addToken(_to, randomId); emit Mint(randomId, msg.sender, _to); emit Transfer(addressZero, _to, randomId); return randomId; } function generateRandom() internal returns (uint256) { uint256 maxIndex = MAX_SUPPLY - totalMinted; uint256 random = uint256(keccak256( abi.encodePacked( msg.sender, block.coinbase, block.difficulty, block.gaslimit, block.timestamp, nonce ) )) % maxIndex; uint256 value = 0; if (tokenMatrix[random] == 0) { // If this matrix position is empty, set the value to the generated random number. value = random; } else { // Otherwise, use the previously stored number from the matrix. value = tokenMatrix[random]; } // If the last available tokenID is still unused... if (tokenMatrix[maxIndex - 1] == 0) { // ...store that ID in the current matrix position. tokenMatrix[random] = maxIndex - 1; } else { // ...otherwise copy over the stored number to the current matrix position. tokenMatrix[random] = tokenMatrix[maxIndex - 1]; } nonce++; return value + startFrom; } function _addToken(address _to, uint256 _tokenId) private notZeroAddress(_to) { tokenToOwner[_tokenId] = _to; ownerToTokensSet[_to].add(_tokenId); } function _removeToken(address _from, uint256 _tokenId) private { if (tokenToOwner[_tokenId] != _from) return; if (tokenToApproval[_tokenId] != addressZero) delete tokenToApproval[_tokenId]; delete tokenToOwner[_tokenId]; ownerToTokensSet[_from].remove(_tokenId); } function _transfer(address _from, address _to, uint256 _tokenId) private { require(tokenToOwner[_tokenId] == _from, "wrongFrom"); _removeToken(_from, _tokenId); _addToken(_to, _tokenId); emit Transfer(_from, _to, _tokenId); } function _safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes memory _data) private transferApproved(_tokenId) validTokenId(_tokenId) notZeroAddress(_to) { _transfer(_from, _to, _tokenId); if (isContract(_to)) { bytes4 retval = IERC721Receiver(_to).onERC721Received(msg.sender, _from, _tokenId, _data); require(retval == MAGIC_ON_ERC721_RECEIVED); } } function _setBaseURI(string memory baseURI_) private { _baseURI = baseURI_; } /*************************************************************************** */ /*************************************************************************** */ // Admin functions: function changeBaseURI(string memory baseURI) external onlyOwner { _setBaseURI(baseURI); } function _enableMinting() external onlyOwner { if (!isMintingEnabled) { isMintingEnabled = true; emit MintingEnabled(); } } function _disableMinting() external onlyOwner { if (isMintingEnabled) { isMintingEnabled = false; emit MintingDisabled(); } } function _setMintingPrice(uint256[] calldata newPrices) external onlyOwner { require(newPrices.length == 2, "length"); require(newPrices[0] > 0 && newPrices[1] > 0, "invalid"); mintingLevelPrices = [newPrices[0], newPrices[1]]; } function _claimETC(uint256 amount) external onlyOwner { payable(msg.sender).transfer(amount); } function withdraw() external onlyOwner { uint balance = address(this).balance; payable(msg.sender).transfer(balance); } /*************************************************************************** */ /*************************************************************************** */ // Service: function isContract(address _addr) internal view returns (bool addressCheck) { uint256 size; assembly { size := extcodesize(_addr) } // solhint-disable-line addressCheck = size > 0; } /*************************************************************************** */ /*************************************************************************** */ // Modifiers: modifier validTokenId(uint256 _tokenId) { require(tokenToOwner[_tokenId] != addressZero, "invalidTokenId"); _; } modifier mintingEnabled() { require(isMintingEnabled, "mintDisabled"); _; } modifier transferApproved(uint256 _tokenId) { address tokenOwner = tokenToOwner[_tokenId]; require( tokenOwner == msg.sender || tokenToApproval[_tokenId] == msg.sender || (ownerToOperators[tokenOwner][msg.sender] && tokenOwner != addressZero) , "notApproved" ); _; } modifier canOperate(uint256 _tokenId) { address tokenOwner = tokenToOwner[_tokenId]; require( tokenOwner == msg.sender || (ownerToOperators[tokenOwner][msg.sender] && tokenOwner != addressZero) ,"operationNotApproved" ); _; } modifier notZeroAddress(address _addr) { require(_addr != addressZero, "zeroAddress"); _; } /*************************************************************************** */ /*************************************************************************** */ // Events: // NFT minted event Mint(uint indexed tokenId, address indexed mintedBy, address indexed mintedTo); // ETC is deposited into the contract. event Deposit(address indexed account, uint amount); // ETC is withdrawn from the contract. event Withdraw(address indexed account, uint amount); event MintingEnabled(); event MintingDisabled(); }
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