{{ "language": "Solidity", "sources": { "contracts/MannysGame.sol": { "content": "//SPDX-License-Identifier: MIT\r\npragma solidity >=0.6.0 <0.7.0;\r\n\r\nimport \"@openzeppelin/contracts/token/ERC721/ERC721.sol\";\r\nimport \"@openzeppelin/contracts/access/Ownable.sol\";\r\nimport \"@openzeppelin/contracts/math/SafeMath.sol\";\r\n\r\ncontract MannysGame is ERC721, Ownable {\r\n\r\n using SafeMath for uint256;\r\n\r\n uint16[] mannys;\r\n bool public mintActive = true;\r\n bool public goldMannyMinted = false;\r\n bool public gameWon = false;\r\n uint256 public gameStart;\r\n address public gameWinner;\r\n\r\n mapping(address => uint) public claimedPerWallet;\r\n uint256 public constant price = 0.1 ether;\r\n\r\n address public constant mannyWallet = 0xF3A45Ee798fc560CE080d143D12312185f84aa72;\r\n address public constant vaultWallet = 0x65861c79fA4249ACc971C229eB52f80A3eDEDedc;\r\n\r\n constructor() public ERC721(\"mannys.game\", \"MNYGME\") {\r\n gameStart = now;\r\n\r\n _setBaseURI(\"ipfs://QmSVeNNmfQ2AJbYQveuP4Uhn1HufyAWFhvknLqwqkrspBS/\");\r\n\r\n // token 404 is reserved for game winner so skip it\r\n for(uint16 i = 1; i <= 1616; i++) {\r\n if (i != 404) {\r\n mannys.push(i);\r\n }\r\n }\r\n\r\n // mint token 1 to mannys wallet\r\n mannys[0] = mannys[mannys.length - 1];\r\n mannys.pop();\r\n _safeMint(mannyWallet, 1);\r\n\r\n // mint 1 of each token type to vault wallet\r\n mannys[201] = mannys[mannys.length - 1]; // base rare\r\n mannys.pop();\r\n _safeMint(vaultWallet, 202);\r\n mannys[400] = mannys[mannys.length - 1]; // albino\r\n mannys.pop();\r\n _safeMint(vaultWallet, 401);\r\n mannys[41] = mannys[mannys.length - 1]; // holo\r\n mannys.pop();\r\n _safeMint(vaultWallet, 42);\r\n mannys[143] = mannys[mannys.length - 1]; // inverted\r\n mannys.pop();\r\n _safeMint(vaultWallet, 144);\r\n mannys[65] = mannys[mannys.length - 1]; // silver\r\n mannys.pop();\r\n _safeMint(vaultWallet, 66);\r\n mannys[243] = mannys[mannys.length - 1]; // stone\r\n mannys.pop();\r\n _safeMint(vaultWallet, 244);\r\n mannys[254] = mannys[mannys.length - 1]; // zombie\r\n mannys.pop();\r\n _safeMint(vaultWallet, 255);\r\n }\r\n\r\n function mint(uint numberOfTokens) public payable {\r\n require(mintActive == true, \"mint is not active rn..\");\r\n require(tx.origin == msg.sender, \"dont get Seven'd\");\r\n require(numberOfTokens > 0, \"mint more lol\");\r\n require(numberOfTokens <= 16, \"dont be greedy smh\");\r\n require(numberOfTokens <= mannys.length, \"no more tokens sry\");\r\n require(claimedPerWallet[msg.sender] + numberOfTokens <= 64, \"claimed too many\");\r\n require(msg.value >= price.mul(numberOfTokens), \"more eth pls\");\r\n\r\n // mint a random manny\r\n for (uint i = 0; i < numberOfTokens; i++) {\r\n uint256 randManny = getRandom(mannys);\r\n _safeMint(msg.sender, randManny);\r\n claimedPerWallet[msg.sender] += 1;\r\n }\r\n\r\n uint mannyCut = msg.value * 40 / 100;\r\n payable(mannyWallet).transfer(mannyCut);\r\n }\r\n\r\n function getRandom(uint16[] storage _arr) private returns (uint256) {\r\n uint256 random = _getRandomNumber(_arr);\r\n uint256 tokenId = uint256(_arr[random]);\r\n\r\n _arr[random] = _arr[_arr.length - 1];\r\n _arr.pop();\r\n\r\n return tokenId;\r\n }\r\n\r\n\t/**\r\n * @dev Pseudo-random number generator\r\n\t * if you're able to exploit this you probably deserve to win TBH\r\n */\r\n function _getRandomNumber(uint16[] storage _arr) private view returns (uint256) {\r\n uint256 random = uint256(\r\n keccak256(\r\n abi.encodePacked(\r\n _arr.length,\r\n blockhash(block.number - 1),\r\n block.coinbase,\r\n block.difficulty,\r\n msg.sender\r\n )\r\n )\r\n );\r\n\r\n return random % _arr.length;\r\n }\r\n\r\n function tokensByOwner(address _owner) external view returns(uint16[] memory) {\r\n uint256 tokenCount = balanceOf(_owner);\r\n if (tokenCount == 0) {\r\n return new uint16[](0);\r\n } else {\r\n uint16[] memory result = new uint16[](tokenCount);\r\n uint16 index;\r\n for (index = 0; index < tokenCount; index++) {\r\n result[index] = uint16(tokenOfOwnerByIndex(_owner, index));\r\n }\r\n return result;\r\n }\r\n }\r\n\r\n function mintGoldManny() public {\r\n require(goldMannyMinted == false, \"golden manny already minted...\");\r\n uint16[5] memory zombie = [13, 143, 180, 255, 363];\r\n uint16[16] memory inverted = [10, 17, 44, 60, 64, 77, 78, 144, 155, 165, 168, 216, 219, 298, 329, 397];\r\n uint16[16] memory silver = [7, 24, 66, 76, 85, 127, 148, 167, 172, 186, 210, 287, 303, 304, 348, 396];\r\n uint16[16] memory stone = [11, 33, 36, 58, 108, 138, 171, 173, 184, 190, 209, 231, 234, 244, 308, 332];\r\n uint16[24] memory albinos = [59, 91, 93, 94, 115, 118, 119, 141, 145, 150, 160, 179, 192, 195, 235, \r\n 237, 271, 273, 291, 297, 325, 326, 381, 401];\r\n uint16[24] memory holos = [42, 90, 92, 98, 122, 124, 132, 156, 162, 182, 197, 206, 240, 242, 253, \r\n 306, 335, 341, 351, 382, 387, 390, 391, 399];\r\n\r\n uint16[] memory tokensOwned = this.tokensByOwner(msg.sender);\r\n uint16[] memory points = new uint16[](7);\r\n\r\n for (uint16 k = 0; k < tokensOwned.length; k++) {\r\n uint16 token = tokensOwned[k];\r\n bool isBase = token <= 403;\r\n for (uint16 i = 0; i < 24; i++) {\r\n if (i < albinos.length && albinos[i] == token) {\r\n points[1] = 1;\r\n isBase = false;\r\n } else if (i < holos.length && holos[i] == token) {\r\n points[2] = 1;\r\n isBase = false;\r\n } else if (i < inverted.length && inverted[i] == token) {\r\n points[3] = 1;\r\n isBase = false;\r\n } else if (i < silver.length && silver[i] == token) {\r\n points[4] = 1;\r\n isBase = false;\r\n } else if (i < stone.length && stone[i] == token) {\r\n points[5] = 1;\r\n isBase = false;\r\n } else if (i < zombie.length && zombie[i] == token) {\r\n points[6] = 1;\r\n isBase = false;\r\n }\r\n }\r\n // if checked all special ids and none matched, add base point\r\n if (isBase) {\r\n points[0] = 1;\r\n }\r\n }\r\n\r\n uint16 totalPoints;\r\n for (uint16 j = 0; j < points.length; j++) {\r\n if (points[j] == 1) {\r\n totalPoints += 1;\r\n }\r\n }\r\n\r\n require(totalPoints >= 7, \"not enough points for a golden manny, ngmi...\");\r\n _safeMint(msg.sender, 404);\r\n goldMannyMinted = true;\r\n }\r\n\r\n function winTheGame() public {\r\n require(gameWon == false, \"game has already been won, gg\");\r\n require(this.ownerOf(404) == msg.sender, \"have not acquired the golden manny, smh...\");\r\n msg.sender.transfer(address(this).balance);\r\n gameWon = true;\r\n gameWinner = msg.sender;\r\n }\r\n\r\n // admin\r\n function setBaseURI(string memory baseURI) public onlyOwner {\r\n _setBaseURI(baseURI);\r\n }\r\n\r\n function setMintActive(bool _mintActive) public onlyOwner {\r\n mintActive = _mintActive;\r\n }\r\n\r\n function withdraw() public onlyOwner {\r\n uint256 days404 = 86400 * 404;\r\n // time hasnt expired, so enforce rules\r\n if (now <= gameStart + days404) {\r\n require(gameWon == true, \"game isnt over yet...\");\r\n }\r\n\r\n uint256 balance = address(this).balance;\r\n msg.sender.transfer(balance);\r\n\r\n if (gameWon == false) {\r\n gameWon = true;\r\n gameWinner = msg.sender;\r\n }\r\n }\r\n}" }, "@openzeppelin/contracts/token/ERC721/ERC721.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\nimport \"../../utils/Context.sol\";\nimport \"./IERC721.sol\";\nimport \"./IERC721Metadata.sol\";\nimport \"./IERC721Enumerable.sol\";\nimport \"./IERC721Receiver.sol\";\nimport \"../../introspection/ERC165.sol\";\nimport \"../../math/SafeMath.sol\";\nimport \"../../utils/Address.sol\";\nimport \"../../utils/EnumerableSet.sol\";\nimport \"../../utils/EnumerableMap.sol\";\nimport \"../../utils/Strings.sol\";\n\n/**\n * @title ERC721 Non-Fungible Token Standard basic implementation\n * @dev see https://eips.ethereum.org/EIPS/eip-721\n */\ncontract ERC721 is Context, ERC165, IERC721, IERC721Metadata, IERC721Enumerable {\n using SafeMath for uint256;\n using Address for address;\n using EnumerableSet for EnumerableSet.UintSet;\n using EnumerableMap for EnumerableMap.UintToAddressMap;\n using Strings for uint256;\n\n // Equals to `bytes4(keccak256(\"onERC721Received(address,address,uint256,bytes)\"))`\n // which can be also obtained as `IERC721Receiver(0).onERC721Received.selector`\n bytes4 private constant _ERC721_RECEIVED = 0x150b7a02;\n\n // Mapping from holder address to their (enumerable) set of owned tokens\n mapping (address => EnumerableSet.UintSet) private _holderTokens;\n\n // Enumerable mapping from token ids to their owners\n EnumerableMap.UintToAddressMap private _tokenOwners;\n\n // Mapping from token ID to approved address\n mapping (uint256 => address) private _tokenApprovals;\n\n // Mapping from owner to operator approvals\n mapping (address => mapping (address => bool)) private _operatorApprovals;\n\n // Token name\n string private _name;\n\n // Token symbol\n string private _symbol;\n\n // Optional mapping for token URIs\n mapping (uint256 => string) private _tokenURIs;\n\n // Base URI\n string private _baseURI;\n\n /*\n * bytes4(keccak256('balanceOf(address)')) == 0x70a08231\n * bytes4(keccak256('ownerOf(uint256)')) == 0x6352211e\n * bytes4(keccak256('approve(address,uint256)')) == 0x095ea7b3\n * bytes4(keccak256('getApproved(uint256)')) == 0x081812fc\n * bytes4(keccak256('setApprovalForAll(address,bool)')) == 0xa22cb465\n * bytes4(keccak256('isApprovedForAll(address,address)')) == 0xe985e9c5\n * bytes4(keccak256('transferFrom(address,address,uint256)')) == 0x23b872dd\n * bytes4(keccak256('safeTransferFrom(address,address,uint256)')) == 0x42842e0e\n * bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)')) == 0xb88d4fde\n *\n * => 0x70a08231 ^ 0x6352211e ^ 0x095ea7b3 ^ 0x081812fc ^\n * 0xa22cb465 ^ 0xe985e9c5 ^ 0x23b872dd ^ 0x42842e0e ^ 0xb88d4fde == 0x80ac58cd\n */\n bytes4 private constant _INTERFACE_ID_ERC721 = 0x80ac58cd;\n\n /*\n * bytes4(keccak256('name()')) == 0x06fdde03\n * bytes4(keccak256('symbol()')) == 0x95d89b41\n * bytes4(keccak256('tokenURI(uint256)')) == 0xc87b56dd\n *\n * => 0x06fdde03 ^ 0x95d89b41 ^ 0xc87b56dd == 0x5b5e139f\n */\n bytes4 private constant _INTERFACE_ID_ERC721_METADATA = 0x5b5e139f;\n\n /*\n * bytes4(keccak256('totalSupply()')) == 0x18160ddd\n * bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) == 0x2f745c59\n * bytes4(keccak256('tokenByIndex(uint256)')) == 0x4f6ccce7\n *\n * => 0x18160ddd ^ 0x2f745c59 ^ 0x4f6ccce7 == 0x780e9d63\n */\n bytes4 private constant _INTERFACE_ID_ERC721_ENUMERABLE = 0x780e9d63;\n\n /**\n * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.\n */\n constructor (string memory name_, string memory symbol_) public {\n _name = name_;\n _symbol = symbol_;\n\n // register the supported interfaces to conform to ERC721 via ERC165\n _registerInterface(_INTERFACE_ID_ERC721);\n _registerInterface(_INTERFACE_ID_ERC721_METADATA);\n _registerInterface(_INTERFACE_ID_ERC721_ENUMERABLE);\n }\n\n /**\n * @dev See {IERC721-balanceOf}.\n */\n function balanceOf(address owner) public view virtual override returns (uint256) {\n require(owner != address(0), \"ERC721: balance query for the zero address\");\n return _holderTokens[owner].length();\n }\n\n /**\n * @dev See {IERC721-ownerOf}.\n */\n function ownerOf(uint256 tokenId) public view virtual override returns (address) {\n return _tokenOwners.get(tokenId, \"ERC721: owner query for nonexistent token\");\n }\n\n /**\n * @dev See {IERC721Metadata-name}.\n */\n function name() public view virtual override returns (string memory) {\n return _name;\n }\n\n /**\n * @dev See {IERC721Metadata-symbol}.\n */\n function symbol() public view virtual override returns (string memory) {\n return _symbol;\n }\n\n /**\n * @dev See {IERC721Metadata-tokenURI}.\n */\n function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {\n require(_exists(tokenId), \"ERC721Metadata: URI query for nonexistent token\");\n\n string memory _tokenURI = _tokenURIs[tokenId];\n string memory base = baseURI();\n\n // If there is no base URI, return the token URI.\n if (bytes(base).length == 0) {\n return _tokenURI;\n }\n // If both are set, concatenate the baseURI and tokenURI (via abi.encodePacked).\n if (bytes(_tokenURI).length > 0) {\n return string(abi.encodePacked(base, _tokenURI));\n }\n // If there is a baseURI but no tokenURI, concatenate the tokenID to the baseURI.\n return string(abi.encodePacked(base, tokenId.toString()));\n }\n\n /**\n * @dev Returns the base URI set via {_setBaseURI}. This will be\n * automatically added as a prefix in {tokenURI} to each token's URI, or\n * to the token ID if no specific URI is set for that token ID.\n */\n function baseURI() public view virtual returns (string memory) {\n return _baseURI;\n }\n\n /**\n * @dev See {IERC721Enumerable-tokenOfOwnerByIndex}.\n */\n function tokenOfOwnerByIndex(address owner, uint256 index) public view virtual override returns (uint256) {\n return _holderTokens[owner].at(index);\n }\n\n /**\n * @dev See {IERC721Enumerable-totalSupply}.\n */\n function totalSupply() public view virtual override returns (uint256) {\n // _tokenOwners are indexed by tokenIds, so .length() returns the number of tokenIds\n return _tokenOwners.length();\n }\n\n /**\n * @dev See {IERC721Enumerable-tokenByIndex}.\n */\n function tokenByIndex(uint256 index) public view virtual override returns (uint256) {\n (uint256 tokenId, ) = _tokenOwners.at(index);\n return tokenId;\n }\n\n /**\n * @dev See {IERC721-approve}.\n */\n function approve(address to, uint256 tokenId) public virtual override {\n address owner = ERC721.ownerOf(tokenId);\n require(to != owner, \"ERC721: approval to current owner\");\n\n require(_msgSender() == owner || ERC721.isApprovedForAll(owner, _msgSender()),\n \"ERC721: approve caller is not owner nor approved for all\"\n );\n\n _approve(to, tokenId);\n }\n\n /**\n * @dev See {IERC721-getApproved}.\n */\n function getApproved(uint256 tokenId) public view virtual override returns (address) {\n require(_exists(tokenId), \"ERC721: approved query for nonexistent token\");\n\n return _tokenApprovals[tokenId];\n }\n\n /**\n * @dev See {IERC721-setApprovalForAll}.\n */\n function setApprovalForAll(address operator, bool approved) public virtual override {\n require(operator != _msgSender(), \"ERC721: approve to caller\");\n\n _operatorApprovals[_msgSender()][operator] = approved;\n emit ApprovalForAll(_msgSender(), operator, approved);\n }\n\n /**\n * @dev See {IERC721-isApprovedForAll}.\n */\n function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {\n return _operatorApprovals[owner][operator];\n }\n\n /**\n * @dev See {IERC721-transferFrom}.\n */\n function transferFrom(address from, address to, uint256 tokenId) public virtual override {\n //solhint-disable-next-line max-line-length\n require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: transfer caller is not owner nor approved\");\n\n _transfer(from, to, tokenId);\n }\n\n /**\n * @dev See {IERC721-safeTransferFrom}.\n */\n function safeTransferFrom(address from, address to, uint256 tokenId) public virtual override {\n safeTransferFrom(from, to, tokenId, \"\");\n }\n\n /**\n * @dev See {IERC721-safeTransferFrom}.\n */\n function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public virtual override {\n require(_isApprovedOrOwner(_msgSender(), tokenId), \"ERC721: transfer caller is not owner nor approved\");\n _safeTransfer(from, to, tokenId, _data);\n }\n\n /**\n * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients\n * are aware of the ERC721 protocol to prevent tokens from being forever locked.\n *\n * `_data` is additional data, it has no specified format and it is sent in call to `to`.\n *\n * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.\n * implement alternative mechanisms to perform token transfer, such as signature-based.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `tokenId` token must exist and be owned by `from`.\n * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n *\n * Emits a {Transfer} event.\n */\n function _safeTransfer(address from, address to, uint256 tokenId, bytes memory _data) internal virtual {\n _transfer(from, to, tokenId);\n require(_checkOnERC721Received(from, to, tokenId, _data), \"ERC721: transfer to non ERC721Receiver implementer\");\n }\n\n /**\n * @dev Returns whether `tokenId` exists.\n *\n * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.\n *\n * Tokens start existing when they are minted (`_mint`),\n * and stop existing when they are burned (`_burn`).\n */\n function _exists(uint256 tokenId) internal view virtual returns (bool) {\n return _tokenOwners.contains(tokenId);\n }\n\n /**\n * @dev Returns whether `spender` is allowed to manage `tokenId`.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n */\n function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {\n require(_exists(tokenId), \"ERC721: operator query for nonexistent token\");\n address owner = ERC721.ownerOf(tokenId);\n return (spender == owner || getApproved(tokenId) == spender || ERC721.isApprovedForAll(owner, spender));\n }\n\n /**\n * @dev Safely mints `tokenId` and transfers it to `to`.\n *\n * Requirements:\n d*\n * - `tokenId` must not exist.\n * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n *\n * Emits a {Transfer} event.\n */\n function _safeMint(address to, uint256 tokenId) internal virtual {\n _safeMint(to, tokenId, \"\");\n }\n\n /**\n * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is\n * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.\n */\n function _safeMint(address to, uint256 tokenId, bytes memory _data) internal virtual {\n _mint(to, tokenId);\n require(_checkOnERC721Received(address(0), to, tokenId, _data), \"ERC721: transfer to non ERC721Receiver implementer\");\n }\n\n /**\n * @dev Mints `tokenId` and transfers it to `to`.\n *\n * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible\n *\n * Requirements:\n *\n * - `tokenId` must not exist.\n * - `to` cannot be the zero address.\n *\n * Emits a {Transfer} event.\n */\n function _mint(address to, uint256 tokenId) internal virtual {\n require(to != address(0), \"ERC721: mint to the zero address\");\n require(!_exists(tokenId), \"ERC721: token already minted\");\n\n _beforeTokenTransfer(address(0), to, tokenId);\n\n _holderTokens[to].add(tokenId);\n\n _tokenOwners.set(tokenId, to);\n\n emit Transfer(address(0), to, tokenId);\n }\n\n /**\n * @dev Destroys `tokenId`.\n * The approval is cleared when the token is burned.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n *\n * Emits a {Transfer} event.\n */\n function _burn(uint256 tokenId) internal virtual {\n address owner = ERC721.ownerOf(tokenId); // internal owner\n\n _beforeTokenTransfer(owner, address(0), tokenId);\n\n // Clear approvals\n _approve(address(0), tokenId);\n\n // Clear metadata (if any)\n if (bytes(_tokenURIs[tokenId]).length != 0) {\n delete _tokenURIs[tokenId];\n }\n\n _holderTokens[owner].remove(tokenId);\n\n _tokenOwners.remove(tokenId);\n\n emit Transfer(owner, address(0), tokenId);\n }\n\n /**\n * @dev Transfers `tokenId` from `from` to `to`.\n * As opposed to {transferFrom}, this imposes no restrictions on msg.sender.\n *\n * Requirements:\n *\n * - `to` cannot be the zero address.\n * - `tokenId` token must be owned by `from`.\n *\n * Emits a {Transfer} event.\n */\n function _transfer(address from, address to, uint256 tokenId) internal virtual {\n require(ERC721.ownerOf(tokenId) == from, \"ERC721: transfer of token that is not own\"); // internal owner\n require(to != address(0), \"ERC721: transfer to the zero address\");\n\n _beforeTokenTransfer(from, to, tokenId);\n\n // Clear approvals from the previous owner\n _approve(address(0), tokenId);\n\n _holderTokens[from].remove(tokenId);\n _holderTokens[to].add(tokenId);\n\n _tokenOwners.set(tokenId, to);\n\n emit Transfer(from, to, tokenId);\n }\n\n /**\n * @dev Sets `_tokenURI` as the tokenURI of `tokenId`.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n */\n function _setTokenURI(uint256 tokenId, string memory _tokenURI) internal virtual {\n require(_exists(tokenId), \"ERC721Metadata: URI set of nonexistent token\");\n _tokenURIs[tokenId] = _tokenURI;\n }\n\n /**\n * @dev Internal function to set the base URI for all token IDs. It is\n * automatically added as a prefix to the value returned in {tokenURI},\n * or to the token ID if {tokenURI} is empty.\n */\n function _setBaseURI(string memory baseURI_) internal virtual {\n _baseURI = baseURI_;\n }\n\n /**\n * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.\n * The call is not executed if the target address is not a contract.\n *\n * @param from address representing the previous owner of the given token ID\n * @param to target address that will receive the tokens\n * @param tokenId uint256 ID of the token to be transferred\n * @param _data bytes optional data to send along with the call\n * @return bool whether the call correctly returned the expected magic value\n */\n function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data)\n private returns (bool)\n {\n if (!to.isContract()) {\n return true;\n }\n bytes memory returndata = to.functionCall(abi.encodeWithSelector(\n IERC721Receiver(to).onERC721Received.selector,\n _msgSender(),\n from,\n tokenId,\n _data\n ), \"ERC721: transfer to non ERC721Receiver implementer\");\n bytes4 retval = abi.decode(returndata, (bytes4));\n return (retval == _ERC721_RECEIVED);\n }\n\n /**\n * @dev Approve `to` to operate on `tokenId`\n *\n * Emits an {Approval} event.\n */\n function _approve(address to, uint256 tokenId) internal virtual {\n _tokenApprovals[tokenId] = to;\n emit Approval(ERC721.ownerOf(tokenId), to, tokenId); // internal owner\n }\n\n /**\n * @dev Hook that is called before any token transfer. This includes minting\n * and burning.\n *\n * Calling conditions:\n *\n * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be\n * transferred to `to`.\n * - When `from` is zero, `tokenId` will be minted for `to`.\n * - When `to` is zero, ``from``'s `tokenId` will be burned.\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n *\n * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n */\n function _beforeTokenTransfer(address from, address to, uint256 tokenId) internal virtual { }\n}\n" }, "@openzeppelin/contracts/access/Ownable.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\nimport \"../utils/Context.sol\";\n/**\n * @dev Contract module which provides a basic access control mechanism, where\n * there is an account (an owner) that can be granted exclusive access to\n * specific functions.\n *\n * By default, the owner account will be the one that deploys the contract. This\n * can later be changed with {transferOwnership}.\n *\n * This module is used through inheritance. It will make available the modifier\n * `onlyOwner`, which can be applied to your functions to restrict their use to\n * the owner.\n */\nabstract contract Ownable is Context {\n address private _owner;\n\n event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\n\n /**\n * @dev Initializes the contract setting the deployer as the initial owner.\n */\n constructor () internal {\n address msgSender = _msgSender();\n _owner = msgSender;\n emit OwnershipTransferred(address(0), msgSender);\n }\n\n /**\n * @dev Returns the address of the current owner.\n */\n function owner() public view virtual returns (address) {\n return _owner;\n }\n\n /**\n * @dev Throws if called by any account other than the owner.\n */\n modifier onlyOwner() {\n require(owner() == _msgSender(), \"Ownable: caller is not the owner\");\n _;\n }\n\n /**\n * @dev Leaves the contract without owner. It will not be possible to call\n * `onlyOwner` functions anymore. Can only be called by the current owner.\n *\n * NOTE: Renouncing ownership will leave the contract without an owner,\n * thereby removing any functionality that is only available to the owner.\n */\n function renounceOwnership() public virtual onlyOwner {\n emit OwnershipTransferred(_owner, address(0));\n _owner = address(0);\n }\n\n /**\n * @dev Transfers ownership of the contract to a new account (`newOwner`).\n * Can only be called by the current owner.\n */\n function transferOwnership(address newOwner) public virtual onlyOwner {\n require(newOwner != address(0), \"Ownable: new owner is the zero address\");\n emit OwnershipTransferred(_owner, newOwner);\n _owner = newOwner;\n }\n}\n" }, "@openzeppelin/contracts/math/SafeMath.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @dev Wrappers over Solidity's arithmetic operations with added overflow\n * checks.\n *\n * Arithmetic operations in Solidity wrap on overflow. This can easily result\n * in bugs, because programmers usually assume that an overflow raises an\n * error, which is the standard behavior in high level programming languages.\n * `SafeMath` restores this intuition by reverting the transaction when an\n * operation overflows.\n *\n * Using this library instead of the unchecked operations eliminates an entire\n * class of bugs, so it's recommended to use it always.\n */\nlibrary SafeMath {\n /**\n * @dev Returns the addition of two unsigned integers, with an overflow flag.\n *\n * _Available since v3.4._\n */\n function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {\n uint256 c = a + b;\n if (c < a) return (false, 0);\n return (true, c);\n }\n\n /**\n * @dev Returns the substraction of two unsigned integers, with an overflow flag.\n *\n * _Available since v3.4._\n */\n function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {\n if (b > a) return (false, 0);\n return (true, a - b);\n }\n\n /**\n * @dev Returns the multiplication of two unsigned integers, with an overflow flag.\n *\n * _Available since v3.4._\n */\n function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {\n // Gas optimization: this is cheaper than requiring 'a' not being zero, but the\n // benefit is lost if 'b' is also tested.\n // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522\n if (a == 0) return (true, 0);\n uint256 c = a * b;\n if (c / a != b) return (false, 0);\n return (true, c);\n }\n\n /**\n * @dev Returns the division of two unsigned integers, with a division by zero flag.\n *\n * _Available since v3.4._\n */\n function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {\n if (b == 0) return (false, 0);\n return (true, a / b);\n }\n\n /**\n * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.\n *\n * _Available since v3.4._\n */\n function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {\n if (b == 0) return (false, 0);\n return (true, a % b);\n }\n\n /**\n * @dev Returns the addition of two unsigned integers, reverting on\n * overflow.\n *\n * Counterpart to Solidity's `+` operator.\n *\n * Requirements:\n *\n * - Addition cannot overflow.\n */\n function add(uint256 a, uint256 b) internal pure returns (uint256) {\n uint256 c = a + b;\n require(c >= a, \"SafeMath: addition overflow\");\n return c;\n }\n\n /**\n * @dev Returns the subtraction of two unsigned integers, reverting on\n * overflow (when the result is negative).\n *\n * Counterpart to Solidity's `-` operator.\n *\n * Requirements:\n *\n * - Subtraction cannot overflow.\n */\n function sub(uint256 a, uint256 b) internal pure returns (uint256) {\n require(b <= a, \"SafeMath: subtraction overflow\");\n return a - b;\n }\n\n /**\n * @dev Returns the multiplication of two unsigned integers, reverting on\n * overflow.\n *\n * Counterpart to Solidity's `*` operator.\n *\n * Requirements:\n *\n * - Multiplication cannot overflow.\n */\n function mul(uint256 a, uint256 b) internal pure returns (uint256) {\n if (a == 0) return 0;\n uint256 c = a * b;\n require(c / a == b, \"SafeMath: multiplication overflow\");\n return c;\n }\n\n /**\n * @dev Returns the integer division of two unsigned integers, reverting on\n * division by zero. The result is rounded towards zero.\n *\n * Counterpart to Solidity's `/` operator. Note: this function uses a\n * `revert` opcode (which leaves remaining gas untouched) while Solidity\n * uses an invalid opcode to revert (consuming all remaining gas).\n *\n * Requirements:\n *\n * - The divisor cannot be zero.\n */\n function div(uint256 a, uint256 b) internal pure returns (uint256) {\n require(b > 0, \"SafeMath: division by zero\");\n return a / b;\n }\n\n /**\n * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\n * reverting when dividing by zero.\n *\n * Counterpart to Solidity's `%` operator. This function uses a `revert`\n * opcode (which leaves remaining gas untouched) while Solidity uses an\n * invalid opcode to revert (consuming all remaining gas).\n *\n * Requirements:\n *\n * - The divisor cannot be zero.\n */\n function mod(uint256 a, uint256 b) internal pure returns (uint256) {\n require(b > 0, \"SafeMath: modulo by zero\");\n return a % b;\n }\n\n /**\n * @dev Returns the subtraction of two unsigned integers, reverting with custom message on\n * overflow (when the result is negative).\n *\n * CAUTION: This function is deprecated because it requires allocating memory for the error\n * message unnecessarily. For custom revert reasons use {trySub}.\n *\n * Counterpart to Solidity's `-` operator.\n *\n * Requirements:\n *\n * - Subtraction cannot overflow.\n */\n function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n require(b <= a, errorMessage);\n return a - b;\n }\n\n /**\n * @dev Returns the integer division of two unsigned integers, reverting with custom message on\n * division by zero. The result is rounded towards zero.\n *\n * CAUTION: This function is deprecated because it requires allocating memory for the error\n * message unnecessarily. For custom revert reasons use {tryDiv}.\n *\n * Counterpart to Solidity's `/` operator. Note: this function uses a\n * `revert` opcode (which leaves remaining gas untouched) while Solidity\n * uses an invalid opcode to revert (consuming all remaining gas).\n *\n * Requirements:\n *\n * - The divisor cannot be zero.\n */\n function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n require(b > 0, errorMessage);\n return a / b;\n }\n\n /**\n * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),\n * reverting with custom message when dividing by zero.\n *\n * CAUTION: This function is deprecated because it requires allocating memory for the error\n * message unnecessarily. For custom revert reasons use {tryMod}.\n *\n * Counterpart to Solidity's `%` operator. This function uses a `revert`\n * opcode (which leaves remaining gas untouched) while Solidity uses an\n * invalid opcode to revert (consuming all remaining gas).\n *\n * Requirements:\n *\n * - The divisor cannot be zero.\n */\n function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {\n require(b > 0, errorMessage);\n return a % b;\n }\n}\n" }, "@openzeppelin/contracts/utils/Context.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/*\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with GSN meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n function _msgSender() internal view virtual returns (address payable) {\n return msg.sender;\n }\n\n function _msgData() internal view virtual returns (bytes memory) {\n this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691\n return msg.data;\n }\n}\n" }, "@openzeppelin/contracts/token/ERC721/IERC721.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.2 <0.8.0;\n\nimport \"../../introspection/IERC165.sol\";\n\n/**\n * @dev Required interface of an ERC721 compliant contract.\n */\ninterface IERC721 is IERC165 {\n /**\n * @dev Emitted when `tokenId` token is transferred from `from` to `to`.\n */\n event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);\n\n /**\n * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.\n */\n event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);\n\n /**\n * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.\n */\n event ApprovalForAll(address indexed owner, address indexed operator, bool approved);\n\n /**\n * @dev Returns the number of tokens in ``owner``'s account.\n */\n function balanceOf(address owner) external view returns (uint256 balance);\n\n /**\n * @dev Returns the owner of the `tokenId` token.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n */\n function ownerOf(uint256 tokenId) external view returns (address owner);\n\n /**\n * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients\n * are aware of the ERC721 protocol to prevent tokens from being forever locked.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `tokenId` token must exist and be owned by `from`.\n * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.\n * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n *\n * Emits a {Transfer} event.\n */\n function safeTransferFrom(address from, address to, uint256 tokenId) external;\n\n /**\n * @dev Transfers `tokenId` token from `from` to `to`.\n *\n * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `tokenId` token must be owned by `from`.\n * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.\n *\n * Emits a {Transfer} event.\n */\n function transferFrom(address from, address to, uint256 tokenId) external;\n\n /**\n * @dev Gives permission to `to` to transfer `tokenId` token to another account.\n * The approval is cleared when the token is transferred.\n *\n * Only a single account can be approved at a time, so approving the zero address clears previous approvals.\n *\n * Requirements:\n *\n * - The caller must own the token or be an approved operator.\n * - `tokenId` must exist.\n *\n * Emits an {Approval} event.\n */\n function approve(address to, uint256 tokenId) external;\n\n /**\n * @dev Returns the account approved for `tokenId` token.\n *\n * Requirements:\n *\n * - `tokenId` must exist.\n */\n function getApproved(uint256 tokenId) external view returns (address operator);\n\n /**\n * @dev Approve or remove `operator` as an operator for the caller.\n * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.\n *\n * Requirements:\n *\n * - The `operator` cannot be the caller.\n *\n * Emits an {ApprovalForAll} event.\n */\n function setApprovalForAll(address operator, bool _approved) external;\n\n /**\n * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.\n *\n * See {setApprovalForAll}\n */\n function isApprovedForAll(address owner, address operator) external view returns (bool);\n\n /**\n * @dev Safely transfers `tokenId` token from `from` to `to`.\n *\n * Requirements:\n *\n * - `from` cannot be the zero address.\n * - `to` cannot be the zero address.\n * - `tokenId` token must exist and be owned by `from`.\n * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.\n * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n *\n * Emits a {Transfer} event.\n */\n function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;\n}\n" }, "@openzeppelin/contracts/token/ERC721/IERC721Metadata.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.2 <0.8.0;\n\nimport \"./IERC721.sol\";\n\n/**\n * @title ERC-721 Non-Fungible Token Standard, optional metadata extension\n * @dev See https://eips.ethereum.org/EIPS/eip-721\n */\ninterface IERC721Metadata is IERC721 {\n\n /**\n * @dev Returns the token collection name.\n */\n function name() external view returns (string memory);\n\n /**\n * @dev Returns the token collection symbol.\n */\n function symbol() external view returns (string memory);\n\n /**\n * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.\n */\n function tokenURI(uint256 tokenId) external view returns (string memory);\n}\n" }, "@openzeppelin/contracts/token/ERC721/IERC721Enumerable.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.2 <0.8.0;\n\nimport \"./IERC721.sol\";\n\n/**\n * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension\n * @dev See https://eips.ethereum.org/EIPS/eip-721\n */\ninterface IERC721Enumerable is IERC721 {\n\n /**\n * @dev Returns the total amount of tokens stored by the contract.\n */\n function totalSupply() external view returns (uint256);\n\n /**\n * @dev Returns a token ID owned by `owner` at a given `index` of its token list.\n * Use along with {balanceOf} to enumerate all of ``owner``'s tokens.\n */\n function tokenOfOwnerByIndex(address owner, uint256 index) external view returns (uint256 tokenId);\n\n /**\n * @dev Returns a token ID at a given `index` of all the tokens stored by the contract.\n * Use along with {totalSupply} to enumerate all tokens.\n */\n function tokenByIndex(uint256 index) external view returns (uint256);\n}\n" }, "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @title ERC721 token receiver interface\n * @dev Interface for any contract that wants to support safeTransfers\n * from ERC721 asset contracts.\n */\ninterface IERC721Receiver {\n /**\n * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}\n * by `operator` from `from`, this function is called.\n *\n * It must return its Solidity selector to confirm the token transfer.\n * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.\n *\n * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.\n */\n function onERC721Received(address operator, address from, uint256 tokenId, bytes calldata data) external returns (bytes4);\n}\n" }, "@openzeppelin/contracts/introspection/ERC165.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\nimport \"./IERC165.sol\";\n\n/**\n * @dev Implementation of the {IERC165} interface.\n *\n * Contracts may inherit from this and call {_registerInterface} to declare\n * their support of an interface.\n */\nabstract contract ERC165 is IERC165 {\n /*\n * bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7\n */\n bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;\n\n /**\n * @dev Mapping of interface ids to whether or not it's supported.\n */\n mapping(bytes4 => bool) private _supportedInterfaces;\n\n constructor () internal {\n // Derived contracts need only register support for their own interfaces,\n // we register support for ERC165 itself here\n _registerInterface(_INTERFACE_ID_ERC165);\n }\n\n /**\n * @dev See {IERC165-supportsInterface}.\n *\n * Time complexity O(1), guaranteed to always use less than 30 000 gas.\n */\n function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {\n return _supportedInterfaces[interfaceId];\n }\n\n /**\n * @dev Registers the contract as an implementer of the interface defined by\n * `interfaceId`. Support of the actual ERC165 interface is automatic and\n * registering its interface id is not required.\n *\n * See {IERC165-supportsInterface}.\n *\n * Requirements:\n *\n * - `interfaceId` cannot be the ERC165 invalid interface (`0xffffffff`).\n */\n function _registerInterface(bytes4 interfaceId) internal virtual {\n require(interfaceId != 0xffffffff, \"ERC165: invalid interface id\");\n _supportedInterfaces[interfaceId] = true;\n }\n}\n" }, "@openzeppelin/contracts/utils/Address.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.2 <0.8.0;\n\n/**\n * @dev Collection of functions related to the address type\n */\nlibrary Address {\n /**\n * @dev Returns true if `account` is a contract.\n *\n * [IMPORTANT]\n * ====\n * It is unsafe to assume that an address for which this function returns\n * false is an externally-owned account (EOA) and not a contract.\n *\n * Among others, `isContract` will return false for the following\n * types of addresses:\n *\n * - an externally-owned account\n * - a contract in construction\n * - an address where a contract will be created\n * - an address where a contract lived, but was destroyed\n * ====\n */\n function isContract(address account) internal view returns (bool) {\n // This method relies on extcodesize, which returns 0 for contracts in\n // construction, since the code is only stored at the end of the\n // constructor execution.\n\n uint256 size;\n // solhint-disable-next-line no-inline-assembly\n assembly { size := extcodesize(account) }\n return size > 0;\n }\n\n /**\n * @dev Replacement for Solidity's `transfer`: sends `amount` wei to\n * `recipient`, forwarding all available gas and reverting on errors.\n *\n * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost\n * of certain opcodes, possibly making contracts go over the 2300 gas limit\n * imposed by `transfer`, making them unable to receive funds via\n * `transfer`. {sendValue} removes this limitation.\n *\n * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].\n *\n * IMPORTANT: because control is transferred to `recipient`, care must be\n * taken to not create reentrancy vulnerabilities. Consider using\n * {ReentrancyGuard} or the\n * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].\n */\n function sendValue(address payable recipient, uint256 amount) internal {\n require(address(this).balance >= amount, \"Address: insufficient balance\");\n\n // solhint-disable-next-line avoid-low-level-calls, avoid-call-value\n (bool success, ) = recipient.call{ value: amount }(\"\");\n require(success, \"Address: unable to send value, recipient may have reverted\");\n }\n\n /**\n * @dev Performs a Solidity function call using a low level `call`. A\n * plain`call` is an unsafe replacement for a function call: use this\n * function instead.\n *\n * If `target` reverts with a revert reason, it is bubbled up by this\n * function (like regular Solidity function calls).\n *\n * Returns the raw returned data. To convert to the expected return value,\n * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].\n *\n * Requirements:\n *\n * - `target` must be a contract.\n * - calling `target` with `data` must not revert.\n *\n * _Available since v3.1._\n */\n function functionCall(address target, bytes memory data) internal returns (bytes memory) {\n return functionCall(target, data, \"Address: low-level call failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with\n * `errorMessage` as a fallback revert reason when `target` reverts.\n *\n * _Available since v3.1._\n */\n function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {\n return functionCallWithValue(target, data, 0, errorMessage);\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n * but also transferring `value` wei to `target`.\n *\n * Requirements:\n *\n * - the calling contract must have an ETH balance of at least `value`.\n * - the called Solidity function must be `payable`.\n *\n * _Available since v3.1._\n */\n function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {\n return functionCallWithValue(target, data, value, \"Address: low-level call with value failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but\n * with `errorMessage` as a fallback revert reason when `target` reverts.\n *\n * _Available since v3.1._\n */\n function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {\n require(address(this).balance >= value, \"Address: insufficient balance for call\");\n require(isContract(target), \"Address: call to non-contract\");\n\n // solhint-disable-next-line avoid-low-level-calls\n (bool success, bytes memory returndata) = target.call{ value: value }(data);\n return _verifyCallResult(success, returndata, errorMessage);\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n * but performing a static call.\n *\n * _Available since v3.3._\n */\n function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {\n return functionStaticCall(target, data, \"Address: low-level static call failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n * but performing a static call.\n *\n * _Available since v3.3._\n */\n function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {\n require(isContract(target), \"Address: static call to non-contract\");\n\n // solhint-disable-next-line avoid-low-level-calls\n (bool success, bytes memory returndata) = target.staticcall(data);\n return _verifyCallResult(success, returndata, errorMessage);\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],\n * but performing a delegate call.\n *\n * _Available since v3.4._\n */\n function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {\n return functionDelegateCall(target, data, \"Address: low-level delegate call failed\");\n }\n\n /**\n * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],\n * but performing a delegate call.\n *\n * _Available since v3.4._\n */\n function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {\n require(isContract(target), \"Address: delegate call to non-contract\");\n\n // solhint-disable-next-line avoid-low-level-calls\n (bool success, bytes memory returndata) = target.delegatecall(data);\n return _verifyCallResult(success, returndata, errorMessage);\n }\n\n function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {\n if (success) {\n return returndata;\n } else {\n // Look for revert reason and bubble it up if present\n if (returndata.length > 0) {\n // The easiest way to bubble the revert reason is using memory via assembly\n\n // solhint-disable-next-line no-inline-assembly\n assembly {\n let returndata_size := mload(returndata)\n revert(add(32, returndata), returndata_size)\n }\n } else {\n revert(errorMessage);\n }\n }\n }\n}\n" }, "@openzeppelin/contracts/utils/EnumerableSet.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @dev Library for managing\n * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive\n * types.\n *\n * Sets have the following properties:\n *\n * - Elements are added, removed, and checked for existence in constant time\n * (O(1)).\n * - Elements are enumerated in O(n). No guarantees are made on the ordering.\n *\n * ```\n * contract Example {\n * // Add the library methods\n * using EnumerableSet for EnumerableSet.AddressSet;\n *\n * // Declare a set state variable\n * EnumerableSet.AddressSet private mySet;\n * }\n * ```\n *\n * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)\n * and `uint256` (`UintSet`) are supported.\n */\nlibrary EnumerableSet {\n // To implement this library for multiple types with as little code\n // repetition as possible, we write it in terms of a generic Set type with\n // bytes32 values.\n // The Set implementation uses private functions, and user-facing\n // implementations (such as AddressSet) are just wrappers around the\n // underlying Set.\n // This means that we can only create new EnumerableSets for types that fit\n // in bytes32.\n\n struct Set {\n // Storage of set values\n bytes32[] _values;\n\n // Position of the value in the `values` array, plus 1 because index 0\n // means a value is not in the set.\n mapping (bytes32 => uint256) _indexes;\n }\n\n /**\n * @dev Add a value to a set. O(1).\n *\n * Returns true if the value was added to the set, that is if it was not\n * already present.\n */\n function _add(Set storage set, bytes32 value) private returns (bool) {\n if (!_contains(set, value)) {\n set._values.push(value);\n // The value is stored at length-1, but we add 1 to all indexes\n // and use 0 as a sentinel value\n set._indexes[value] = set._values.length;\n return true;\n } else {\n return false;\n }\n }\n\n /**\n * @dev Removes a value from a set. O(1).\n *\n * Returns true if the value was removed from the set, that is if it was\n * present.\n */\n function _remove(Set storage set, bytes32 value) private returns (bool) {\n // We read and store the value's index to prevent multiple reads from the same storage slot\n uint256 valueIndex = set._indexes[value];\n\n if (valueIndex != 0) { // Equivalent to contains(set, value)\n // To delete an element from the _values array in O(1), we swap the element to delete with the last one in\n // the array, and then remove the last element (sometimes called as 'swap and pop').\n // This modifies the order of the array, as noted in {at}.\n\n uint256 toDeleteIndex = valueIndex - 1;\n uint256 lastIndex = set._values.length - 1;\n\n // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs\n // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.\n\n bytes32 lastvalue = set._values[lastIndex];\n\n // Move the last value to the index where the value to delete is\n set._values[toDeleteIndex] = lastvalue;\n // Update the index for the moved value\n set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based\n\n // Delete the slot where the moved value was stored\n set._values.pop();\n\n // Delete the index for the deleted slot\n delete set._indexes[value];\n\n return true;\n } else {\n return false;\n }\n }\n\n /**\n * @dev Returns true if the value is in the set. O(1).\n */\n function _contains(Set storage set, bytes32 value) private view returns (bool) {\n return set._indexes[value] != 0;\n }\n\n /**\n * @dev Returns the number of values on the set. O(1).\n */\n function _length(Set storage set) private view returns (uint256) {\n return set._values.length;\n }\n\n /**\n * @dev Returns the value stored at position `index` in the set. O(1).\n *\n * Note that there are no guarantees on the ordering of values inside the\n * array, and it may change when more values are added or removed.\n *\n * Requirements:\n *\n * - `index` must be strictly less than {length}.\n */\n function _at(Set storage set, uint256 index) private view returns (bytes32) {\n require(set._values.length > index, \"EnumerableSet: index out of bounds\");\n return set._values[index];\n }\n\n // Bytes32Set\n\n struct Bytes32Set {\n Set _inner;\n }\n\n /**\n * @dev Add a value to a set. O(1).\n *\n * Returns true if the value was added to the set, that is if it was not\n * already present.\n */\n function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {\n return _add(set._inner, value);\n }\n\n /**\n * @dev Removes a value from a set. O(1).\n *\n * Returns true if the value was removed from the set, that is if it was\n * present.\n */\n function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {\n return _remove(set._inner, value);\n }\n\n /**\n * @dev Returns true if the value is in the set. O(1).\n */\n function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {\n return _contains(set._inner, value);\n }\n\n /**\n * @dev Returns the number of values in the set. O(1).\n */\n function length(Bytes32Set storage set) internal view returns (uint256) {\n return _length(set._inner);\n }\n\n /**\n * @dev Returns the value stored at position `index` in the set. O(1).\n *\n * Note that there are no guarantees on the ordering of values inside the\n * array, and it may change when more values are added or removed.\n *\n * Requirements:\n *\n * - `index` must be strictly less than {length}.\n */\n function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {\n return _at(set._inner, index);\n }\n\n // AddressSet\n\n struct AddressSet {\n Set _inner;\n }\n\n /**\n * @dev Add a value to a set. O(1).\n *\n * Returns true if the value was added to the set, that is if it was not\n * already present.\n */\n function add(AddressSet storage set, address value) internal returns (bool) {\n return _add(set._inner, bytes32(uint256(uint160(value))));\n }\n\n /**\n * @dev Removes a value from a set. O(1).\n *\n * Returns true if the value was removed from the set, that is if it was\n * present.\n */\n function remove(AddressSet storage set, address value) internal returns (bool) {\n return _remove(set._inner, bytes32(uint256(uint160(value))));\n }\n\n /**\n * @dev Returns true if the value is in the set. O(1).\n */\n function contains(AddressSet storage set, address value) internal view returns (bool) {\n return _contains(set._inner, bytes32(uint256(uint160(value))));\n }\n\n /**\n * @dev Returns the number of values in the set. O(1).\n */\n function length(AddressSet storage set) internal view returns (uint256) {\n return _length(set._inner);\n }\n\n /**\n * @dev Returns the value stored at position `index` in the set. O(1).\n *\n * Note that there are no guarantees on the ordering of values inside the\n * array, and it may change when more values are added or removed.\n *\n * Requirements:\n *\n * - `index` must be strictly less than {length}.\n */\n function at(AddressSet storage set, uint256 index) internal view returns (address) {\n return address(uint160(uint256(_at(set._inner, index))));\n }\n\n\n // UintSet\n\n struct UintSet {\n Set _inner;\n }\n\n /**\n * @dev Add a value to a set. O(1).\n *\n * Returns true if the value was added to the set, that is if it was not\n * already present.\n */\n function add(UintSet storage set, uint256 value) internal returns (bool) {\n return _add(set._inner, bytes32(value));\n }\n\n /**\n * @dev Removes a value from a set. O(1).\n *\n * Returns true if the value was removed from the set, that is if it was\n * present.\n */\n function remove(UintSet storage set, uint256 value) internal returns (bool) {\n return _remove(set._inner, bytes32(value));\n }\n\n /**\n * @dev Returns true if the value is in the set. O(1).\n */\n function contains(UintSet storage set, uint256 value) internal view returns (bool) {\n return _contains(set._inner, bytes32(value));\n }\n\n /**\n * @dev Returns the number of values on the set. O(1).\n */\n function length(UintSet storage set) internal view returns (uint256) {\n return _length(set._inner);\n }\n\n /**\n * @dev Returns the value stored at position `index` in the set. O(1).\n *\n * Note that there are no guarantees on the ordering of values inside the\n * array, and it may change when more values are added or removed.\n *\n * Requirements:\n *\n * - `index` must be strictly less than {length}.\n */\n function at(UintSet storage set, uint256 index) internal view returns (uint256) {\n return uint256(_at(set._inner, index));\n }\n}\n" }, "@openzeppelin/contracts/utils/EnumerableMap.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @dev Library for managing an enumerable variant of Solidity's\n * https://solidity.readthedocs.io/en/latest/types.html#mapping-types[`mapping`]\n * type.\n *\n * Maps have the following properties:\n *\n * - Entries are added, removed, and checked for existence in constant time\n * (O(1)).\n * - Entries are enumerated in O(n). No guarantees are made on the ordering.\n *\n * ```\n * contract Example {\n * // Add the library methods\n * using EnumerableMap for EnumerableMap.UintToAddressMap;\n *\n * // Declare a set state variable\n * EnumerableMap.UintToAddressMap private myMap;\n * }\n * ```\n *\n * As of v3.0.0, only maps of type `uint256 -> address` (`UintToAddressMap`) are\n * supported.\n */\nlibrary EnumerableMap {\n // To implement this library for multiple types with as little code\n // repetition as possible, we write it in terms of a generic Map type with\n // bytes32 keys and values.\n // The Map implementation uses private functions, and user-facing\n // implementations (such as Uint256ToAddressMap) are just wrappers around\n // the underlying Map.\n // This means that we can only create new EnumerableMaps for types that fit\n // in bytes32.\n\n struct MapEntry {\n bytes32 _key;\n bytes32 _value;\n }\n\n struct Map {\n // Storage of map keys and values\n MapEntry[] _entries;\n\n // Position of the entry defined by a key in the `entries` array, plus 1\n // because index 0 means a key is not in the map.\n mapping (bytes32 => uint256) _indexes;\n }\n\n /**\n * @dev Adds a key-value pair to a map, or updates the value for an existing\n * key. O(1).\n *\n * Returns true if the key was added to the map, that is if it was not\n * already present.\n */\n function _set(Map storage map, bytes32 key, bytes32 value) private returns (bool) {\n // We read and store the key's index to prevent multiple reads from the same storage slot\n uint256 keyIndex = map._indexes[key];\n\n if (keyIndex == 0) { // Equivalent to !contains(map, key)\n map._entries.push(MapEntry({ _key: key, _value: value }));\n // The entry is stored at length-1, but we add 1 to all indexes\n // and use 0 as a sentinel value\n map._indexes[key] = map._entries.length;\n return true;\n } else {\n map._entries[keyIndex - 1]._value = value;\n return false;\n }\n }\n\n /**\n * @dev Removes a key-value pair from a map. O(1).\n *\n * Returns true if the key was removed from the map, that is if it was present.\n */\n function _remove(Map storage map, bytes32 key) private returns (bool) {\n // We read and store the key's index to prevent multiple reads from the same storage slot\n uint256 keyIndex = map._indexes[key];\n\n if (keyIndex != 0) { // Equivalent to contains(map, key)\n // To delete a key-value pair from the _entries array in O(1), we swap the entry to delete with the last one\n // in the array, and then remove the last entry (sometimes called as 'swap and pop').\n // This modifies the order of the array, as noted in {at}.\n\n uint256 toDeleteIndex = keyIndex - 1;\n uint256 lastIndex = map._entries.length - 1;\n\n // When the entry to delete is the last one, the swap operation is unnecessary. However, since this occurs\n // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.\n\n MapEntry storage lastEntry = map._entries[lastIndex];\n\n // Move the last entry to the index where the entry to delete is\n map._entries[toDeleteIndex] = lastEntry;\n // Update the index for the moved entry\n map._indexes[lastEntry._key] = toDeleteIndex + 1; // All indexes are 1-based\n\n // Delete the slot where the moved entry was stored\n map._entries.pop();\n\n // Delete the index for the deleted slot\n delete map._indexes[key];\n\n return true;\n } else {\n return false;\n }\n }\n\n /**\n * @dev Returns true if the key is in the map. O(1).\n */\n function _contains(Map storage map, bytes32 key) private view returns (bool) {\n return map._indexes[key] != 0;\n }\n\n /**\n * @dev Returns the number of key-value pairs in the map. O(1).\n */\n function _length(Map storage map) private view returns (uint256) {\n return map._entries.length;\n }\n\n /**\n * @dev Returns the key-value pair stored at position `index` in the map. O(1).\n *\n * Note that there are no guarantees on the ordering of entries inside the\n * array, and it may change when more entries are added or removed.\n *\n * Requirements:\n *\n * - `index` must be strictly less than {length}.\n */\n function _at(Map storage map, uint256 index) private view returns (bytes32, bytes32) {\n require(map._entries.length > index, \"EnumerableMap: index out of bounds\");\n\n MapEntry storage entry = map._entries[index];\n return (entry._key, entry._value);\n }\n\n /**\n * @dev Tries to returns the value associated with `key`. O(1).\n * Does not revert if `key` is not in the map.\n */\n function _tryGet(Map storage map, bytes32 key) private view returns (bool, bytes32) {\n uint256 keyIndex = map._indexes[key];\n if (keyIndex == 0) return (false, 0); // Equivalent to contains(map, key)\n return (true, map._entries[keyIndex - 1]._value); // All indexes are 1-based\n }\n\n /**\n * @dev Returns the value associated with `key`. O(1).\n *\n * Requirements:\n *\n * - `key` must be in the map.\n */\n function _get(Map storage map, bytes32 key) private view returns (bytes32) {\n uint256 keyIndex = map._indexes[key];\n require(keyIndex != 0, \"EnumerableMap: nonexistent key\"); // Equivalent to contains(map, key)\n return map._entries[keyIndex - 1]._value; // All indexes are 1-based\n }\n\n /**\n * @dev Same as {_get}, with a custom error message when `key` is not in the map.\n *\n * CAUTION: This function is deprecated because it requires allocating memory for the error\n * message unnecessarily. For custom revert reasons use {_tryGet}.\n */\n function _get(Map storage map, bytes32 key, string memory errorMessage) private view returns (bytes32) {\n uint256 keyIndex = map._indexes[key];\n require(keyIndex != 0, errorMessage); // Equivalent to contains(map, key)\n return map._entries[keyIndex - 1]._value; // All indexes are 1-based\n }\n\n // UintToAddressMap\n\n struct UintToAddressMap {\n Map _inner;\n }\n\n /**\n * @dev Adds a key-value pair to a map, or updates the value for an existing\n * key. O(1).\n *\n * Returns true if the key was added to the map, that is if it was not\n * already present.\n */\n function set(UintToAddressMap storage map, uint256 key, address value) internal returns (bool) {\n return _set(map._inner, bytes32(key), bytes32(uint256(uint160(value))));\n }\n\n /**\n * @dev Removes a value from a set. O(1).\n *\n * Returns true if the key was removed from the map, that is if it was present.\n */\n function remove(UintToAddressMap storage map, uint256 key) internal returns (bool) {\n return _remove(map._inner, bytes32(key));\n }\n\n /**\n * @dev Returns true if the key is in the map. O(1).\n */\n function contains(UintToAddressMap storage map, uint256 key) internal view returns (bool) {\n return _contains(map._inner, bytes32(key));\n }\n\n /**\n * @dev Returns the number of elements in the map. O(1).\n */\n function length(UintToAddressMap storage map) internal view returns (uint256) {\n return _length(map._inner);\n }\n\n /**\n * @dev Returns the element stored at position `index` in the set. O(1).\n * Note that there are no guarantees on the ordering of values inside the\n * array, and it may change when more values are added or removed.\n *\n * Requirements:\n *\n * - `index` must be strictly less than {length}.\n */\n function at(UintToAddressMap storage map, uint256 index) internal view returns (uint256, address) {\n (bytes32 key, bytes32 value) = _at(map._inner, index);\n return (uint256(key), address(uint160(uint256(value))));\n }\n\n /**\n * @dev Tries to returns the value associated with `key`. O(1).\n * Does not revert if `key` is not in the map.\n *\n * _Available since v3.4._\n */\n function tryGet(UintToAddressMap storage map, uint256 key) internal view returns (bool, address) {\n (bool success, bytes32 value) = _tryGet(map._inner, bytes32(key));\n return (success, address(uint160(uint256(value))));\n }\n\n /**\n * @dev Returns the value associated with `key`. O(1).\n *\n * Requirements:\n *\n * - `key` must be in the map.\n */\n function get(UintToAddressMap storage map, uint256 key) internal view returns (address) {\n return address(uint160(uint256(_get(map._inner, bytes32(key)))));\n }\n\n /**\n * @dev Same as {get}, with a custom error message when `key` is not in the map.\n *\n * CAUTION: This function is deprecated because it requires allocating memory for the error\n * message unnecessarily. For custom revert reasons use {tryGet}.\n */\n function get(UintToAddressMap storage map, uint256 key, string memory errorMessage) internal view returns (address) {\n return address(uint160(uint256(_get(map._inner, bytes32(key), errorMessage))));\n }\n}\n" }, "@openzeppelin/contracts/utils/Strings.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @dev String operations.\n */\nlibrary Strings {\n /**\n * @dev Converts a `uint256` to its ASCII `string` representation.\n */\n function toString(uint256 value) internal pure returns (string memory) {\n // Inspired by OraclizeAPI's implementation - MIT licence\n // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol\n\n if (value == 0) {\n return \"0\";\n }\n uint256 temp = value;\n uint256 digits;\n while (temp != 0) {\n digits++;\n temp /= 10;\n }\n bytes memory buffer = new bytes(digits);\n uint256 index = digits - 1;\n temp = value;\n while (temp != 0) {\n buffer[index--] = bytes1(uint8(48 + temp % 10));\n temp /= 10;\n }\n return string(buffer);\n }\n}\n" }, "@openzeppelin/contracts/introspection/IERC165.sol": { "content": "// SPDX-License-Identifier: MIT\n\npragma solidity >=0.6.0 <0.8.0;\n\n/**\n * @dev Interface of the ERC165 standard, as defined in the\n * https://eips.ethereum.org/EIPS/eip-165[EIP].\n *\n * Implementers can declare support of contract interfaces, which can then be\n * queried by others ({ERC165Checker}).\n *\n * For an implementation, see {ERC165}.\n */\ninterface IERC165 {\n /**\n * @dev Returns true if this contract implements the interface defined by\n * `interfaceId`. See the corresponding\n * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]\n * to learn more about how these ids are created.\n *\n * This function call must use less than 30 000 gas.\n */\n function supportsInterface(bytes4 interfaceId) external view returns (bool);\n}\n" } }, "settings": { "optimizer": { "enabled": true, "runs": 200 }, "outputSelection": { "*": { "*": [ "evm.bytecode", "evm.deployedBytecode", "abi" ] } }, "libraries": {} } }}