Contract Source Code:
File 1 of 1 : Lootlang
// SPDX-License-Identifier: MIT
// File: contracts/Gen.sol
pragma solidity ^0.8.7;
contract Gen {
// MAPPINGS //
mapping(string => uint) internal charsMap; // maps characters to numbers for easier access in 'generateWord()' function
mapping(uint => uint) internal tokenIdToSeed; // initial seed for each tokenId minted
mapping(uint => uint[8]) internal tokenIdToShuffleShift; // tokenId => array of inexes for words to be shifted as a result of shuffling
mapping(uint => uint) internal shuffleCount; // tokenId => number of shuffles tokenId has had
mapping(address => bool) internal hasClaimed; // keeps track of addresses that have claimed a mint
/**
* @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);
}
// VARIABLES //
uint16[297] ps = [
1000, 1889, 2889, 3556, 5223, 6223, 7334, 8778, 9334, 9556, 10000,
381, 952, 1428, 1809, 2761, 4856, 6094, 7523, 9523, 9809, 10000,
198, 792, 1584, 2079, 2574, 3267, 3366, 5643, 7029, 9900, 10000,
714, 1071, 1607, 2232, 2945, 4285, 5178, 6516, 7856, 9195, 10000,
385, 1348, 3467, 5201, 6163, 7127, 9824, 9920, 9939, 9958, 10000,
135, 405, 1081, 1216, 1892, 2703, 4325, 5541, 7568, 9730, 10000,
2443, 2932, 3421, 3910, 4561, 5212, 6677, 8470, 9936, 9985, 10000,
1239, 1770, 2655, 4071, 5310, 6726, 7257, 9912, 9947, 9982, 10000,
268, 281, 294, 328, 1668, 4751, 7432, 9979, 9986, 9993, 10000,
291, 679, 1164, 1649, 2329, 3106, 3689, 4951, 6504, 9708, 10000,
353, 706, 1923, 3510, 5097, 7672, 8818, 9964, 9982, 9991, 10000,
755, 1227, 1416, 1605, 1888, 2077, 2171, 3114, 9246, 9812, 10000,
695, 721, 747, 834, 851, 3023, 5195, 6846, 9974, 9991, 10000,
103, 308, 513, 821, 1437, 2566, 3901, 7289, 9958, 9979, 10000,
294, 588, 735, 750, 1337, 2071, 2805, 4127, 6183, 8239, 10000,
88, 1148, 2561, 2738, 3975, 4682, 4859, 5389, 7156, 9983, 10000,
325, 760, 1303, 1629, 1955, 3367, 4670, 6624, 8253, 9990, 10000,
4955, 9910, 9920, 9930, 9940, 9950, 9960, 9970, 9980, 9990, 10000,
214, 428, 641, 663, 1197, 1411, 1454, 2522, 3590, 4658, 10000,
196, 784, 2548, 3332, 4312, 5488, 7644, 9800, 9996, 9998, 10000,
475, 1424, 1661, 2848, 4272, 5933, 8544, 9256, 9968, 9992, 10000,
515, 618, 1133, 1442, 2267, 3298, 4947, 6493, 7730, 9483, 10000,
202, 1412, 3025, 5444, 7662, 9880, 9920, 9940, 9960, 9980, 10000,
23, 252, 480, 2657, 2886, 4719, 7354, 9645, 9874, 9885, 10000,
433, 866, 1732, 3464, 5195, 8659, 9525, 9698, 9871, 9958, 10000,
601, 901, 1502, 2103, 3605, 4806, 6007, 9010, 9310, 9400, 10000,
204, 511, 613, 714, 1737, 3782, 9917, 9968, 9978, 9988, 10000];
string[] nextChars = [
"fbrwsaltpzj",
"gmldslrtnkb",
"blriiluoaey",
"rliktauhooe",
"ruaoiiegfws",
"mfteladsnrg",
"luaarreioyw",
"luiraohezgy",
"urryoiaejlw",
"gredlocstnb",
"iieaaouuytf",
"aollarsieut",
"ussdyoaielf",
"smmupioaeyn",
"aauyiosetgd",
"zolwtmfurny",
"tupiilaores",
"uuaeiosrfyw",
"nudytslaioe",
"puhaoietwyq",
"usraieohhty",
"ebgzplsntrm",
"uoaieeyvxrl",
"snnoheaiuyr",
"oaueeityxth",
"lmaiseeouvx",
"uyooiaelzrl"];
/**
* @dev Maps characters in 'chars' to numbers for easier comparison in 'generateWord()' function
*/
function mapChars() internal {
string[27] memory chars = [" ", "a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"];
for (uint i=0; i<27; i++) {
charsMap[chars[i]] = i;
}
}
/**
* @dev Returns length of a string '_string'.
*/
function stringLength(string memory _string) internal pure returns(uint) {
return bytes(_string).length;
}
/**
* @dev Gets character from 'nextChars'.
*/
function getChar(uint row, uint col) internal view returns(string memory) {
bytes memory line = bytes(nextChars[row]);
string memory temp = new string(1);
bytes memory output = bytes(temp);
output[0] = line[col];
return string(output);
}
/**
* @dev Generates word length (1-16) using a distribution
*/
function determineWordLength(uint rand) internal pure returns(uint) {
uint16[16] memory cumulativeDistribution = [2,99,761,1929,3175,4694,6291,7654,8744,9328,9678,9872,9938,9976,9991,10000];
uint i = 0;
while (i <= 15) {
if (rand <= cumulativeDistribution[i]) {
break;
}
i++;
}
return i+1; // returns word length
}
/**
* @dev Generates a random word of length 1-16, given a '_tokenId' and '_totalSeed' as a seed of randomness
*/
function generateWord(uint256 _tokenId, uint _totalSeed) internal view returns(string memory) { // change visibility
require(_tokenId >= 1 && _tokenId <= 10000, "Invalid tokenId.");
string memory word;
string memory char;
uint lengthRand = (uint(keccak256(abi.encodePacked(_tokenId, _totalSeed)))% 10000); // gets random number between 0 and 10,000
uint rand = (uint(keccak256(abi.encodePacked(_tokenId, lengthRand, _totalSeed)))% 10000) + 1; // gets random number between 1 and 10,000
// generates word
for (uint n=1; n <= determineWordLength(lengthRand); n++) {
// generates letter
uint i = 0;
while (i < 11) { // indexStart of ps[] to indexEnd
if (rand <= ps[(charsMap[char]*11)+i]) {
break;
}
i++;
}
char = getChar(charsMap[char], i);
word = string(abi.encodePacked(word, char)); // appends letter to word
rand = (uint(keccak256(abi.encodePacked(_tokenId, rand, word, n, _totalSeed)))% 10000) + 1; // gets new random number between 1 and 10,000
}
return word;
}
}
// File: @openzeppelin/contracts/utils/cryptography/MerkleProof.sol
pragma solidity ^0.8.0;
/**
* @dev These functions deal with verification of Merkle Trees proofs.
*
* The proofs can be generated using the JavaScript library
* https://github.com/miguelmota/merkletreejs[merkletreejs].
* Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.
*
* See `test/utils/cryptography/MerkleProof.test.js` for some examples.
*/
library MerkleProof {
/**
* @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree
* defined by `root`. For this, a `proof` must be provided, containing
* sibling hashes on the branch from the leaf to the root of the tree. Each
* pair of leaves and each pair of pre-images are assumed to be sorted.
*/
function verify(
bytes32[] memory proof,
bytes32 root,
bytes32 leaf
) internal pure returns (bool) {
bytes32 computedHash = leaf;
for (uint256 i = 0; i < proof.length; i++) {
bytes32 proofElement = proof[i];
if (computedHash <= proofElement) {
// Hash(current computed hash + current element of the proof)
computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
} else {
// Hash(current element of the proof + current computed hash)
computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
}
}
// Check if the computed hash (root) is equal to the provided root
return computedHash == root;
}
}
// File: @openzeppelin/contracts/utils/Context.sol
pragma solidity ^0.8.0;
/**
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// File: @openzeppelin/contracts/access/Ownable.sol
pragma solidity ^0.8.0;
/**
* @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() {
_setOwner(_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 {
_setOwner(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");
_setOwner(newOwner);
}
function _setOwner(address newOwner) private {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// File: @openzeppelin/contracts/utils/introspection/IERC165.sol
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC165 standard, as defined in the
* https://eips.ethereum.org/EIPS/eip-165[EIP].
*
* Implementers can declare support of contract interfaces, which can then be
* queried by others ({ERC165Checker}).
*
* For an implementation, see {ERC165}.
*/
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);
}
// File: @openzeppelin/contracts/utils/introspection/ERC165.sol
pragma solidity ^0.8.0;
/**
* @dev Implementation of the {IERC165} interface.
*
* Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
* for the additional interface id that will be supported. For example:
*
* ```solidity
* function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
* return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
* }
* ```
*
* Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
*/
abstract contract ERC165 is IERC165 {
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
return interfaceId == type(IERC165).interfaceId;
}
}
// File: @openzeppelin/contracts/utils/Strings.sol
pragma solidity ^0.8.0;
/**
* @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);
}
}
// File: @openzeppelin/contracts/utils/Address.sol
pragma solidity ^0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
assembly {
size := extcodesize(account)
}
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain `call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal pure returns (bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// File: @openzeppelin/contracts/token/ERC721/IERC721.sol
pragma solidity ^0.8.0;
/**
* @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;
}
// File: @openzeppelin/contracts/token/ERC721/extensions/IERC721Metadata.sol
pragma solidity ^0.8.0;
/**
* @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);
}
// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol
pragma solidity ^0.8.0;
/**
* @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);
}
// File: @openzeppelin/contracts/token/ERC721/ERC721.sol
pragma solidity ^0.8.0;
/**
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
* the Metadata extension, but not including the Enumerable extension, which is available separately as
* {ERC721Enumerable}.
*/
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
using Address for address;
using Strings for uint256;
// Token name
string private _name;
// Token symbol
string private _symbol;
// Mapping from token ID to owner address
mapping(uint256 => address) private _owners;
// Mapping owner address to token count
mapping(address => uint256) private _balances;
// Mapping from token ID to approved address
mapping(uint256 => address) private _tokenApprovals;
// Mapping from owner to operator approvals
mapping(address => mapping(address => bool)) private _operatorApprovals;
/**
* @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev See {IERC165-supportsInterface}.
*/
function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
return
interfaceId == type(IERC721).interfaceId ||
interfaceId == type(IERC721Metadata).interfaceId ||
super.supportsInterface(interfaceId);
}
/**
* @dev See {IERC721-balanceOf}.
*/
function balanceOf(address owner) public view virtual override returns (uint256) {
require(owner != address(0), "ERC721: balance query for the zero address");
return _balances[owner];
}
/**
* @dev See {IERC721-ownerOf}.
*/
function ownerOf(uint256 tokenId) public view virtual override returns (address) {
address owner = _owners[tokenId];
require(owner != address(0), "ERC721: owner query for nonexistent token");
return owner;
}
/**
* @dev See {IERC721Metadata-name}.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev See {IERC721Metadata-symbol}.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev See {IERC721Metadata-tokenURI}.
*/
function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");
string memory baseURI = _baseURI();
return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
}
/**
* @dev Base URI for computing {tokenURI}. If set, the resulting URI for each
* token will be the concatenation of the `baseURI` and the `tokenId`. Empty
* by default, can be overriden in child contracts.
*/
function _baseURI() internal view virtual returns (string memory) {
return "";
}
/**
* @dev See {IERC721-approve}.
*/
function approve(address to, uint256 tokenId) public virtual override {
address owner = ERC721.ownerOf(tokenId);
require(to != owner, "ERC721: approval to current owner");
require(
_msgSender() == owner || isApprovedForAll(owner, _msgSender()),
"ERC721: approve caller is not owner nor approved for all"
);
_approve(to, tokenId);
}
/**
* @dev See {IERC721-getApproved}.
*/
function getApproved(uint256 tokenId) public view virtual override returns (address) {
require(_exists(tokenId), "ERC721: approved query for nonexistent token");
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/
function setApprovalForAll(address operator, bool approved) public virtual override {
require(operator != _msgSender(), "ERC721: approve to caller");
_operatorApprovals[_msgSender()][operator] = approved;
emit ApprovalForAll(_msgSender(), operator, approved);
}
/**
* @dev See {IERC721-isApprovedForAll}.
*/
function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
return _operatorApprovals[owner][operator];
}
/**
* @dev See {IERC721-transferFrom}.
*/
function transferFrom(
address from,
address to,
uint256 tokenId
) public virtual override {
//solhint-disable-next-line max-line-length
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_transfer(from, to, tokenId);
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId
) public virtual override {
safeTransferFrom(from, to, tokenId, "");
}
/**
* @dev See {IERC721-safeTransferFrom}.
*/
function safeTransferFrom(
address from,
address to,
uint256 tokenId,
bytes memory _data
) public virtual override {
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
_safeTransfer(from, to, tokenId, _data);
}
/**
* @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
* are aware of the ERC721 protocol to prevent tokens from being forever locked.
*
* `_data` is additional data, it has no specified format and it is sent in call to `to`.
*
* This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.
* implement alternative mechanisms to perform token transfer, such as signature-based.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `tokenId` token must exist and be owned by `from`.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function _safeTransfer(
address from,
address to,
uint256 tokenId,
bytes memory _data
) internal virtual {
_transfer(from, to, tokenId);
require(_checkOnERC721Received(from, to, tokenId, _data), "ERC721: transfer to non ERC721Receiver implementer");
}
/**
* @dev Returns whether `tokenId` exists.
*
* Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.
*
* Tokens start existing when they are minted (`_mint`),
* and stop existing when they are burned (`_burn`).
*/
function _exists(uint256 tokenId) internal view virtual returns (bool) {
return _owners[tokenId] != address(0);
}
/**
* @dev Returns whether `spender` is allowed to manage `tokenId`.
*
* Requirements:
*
* - `tokenId` must exist.
*/
function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
require(_exists(tokenId), "ERC721: operator query for nonexistent token");
address owner = ERC721.ownerOf(tokenId);
return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
}
/**
* @dev Safely mints `tokenId` and transfers it to `to`.
*
* Requirements:
*
* - `tokenId` must not exist.
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
*
* Emits a {Transfer} event.
*/
function _safeMint(address to, uint256 tokenId) internal virtual {
_safeMint(to, tokenId, "");
}
/**
* @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is
* forwarded in {IERC721Receiver-onERC721Received} to contract recipients.
*/
function _safeMint(
address to,
uint256 tokenId,
bytes memory _data
) internal virtual {
_mint(to, tokenId);
require(
_checkOnERC721Received(address(0), to, tokenId, _data),
"ERC721: transfer to non ERC721Receiver implementer"
);
}
/**
* @dev Mints `tokenId` and transfers it to `to`.
*
* WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible
*
* Requirements:
*
* - `tokenId` must not exist.
* - `to` cannot be the zero address.
*
* Emits a {Transfer} event.
*/
function _mint(address to, uint256 tokenId) internal virtual {
require(to != address(0), "ERC721: mint to the zero address");
require(!_exists(tokenId), "ERC721: token already minted");
_beforeTokenTransfer(address(0), to, tokenId);
_balances[to] += 1;
_owners[tokenId] = to;
emit Transfer(address(0), to, tokenId);
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/
function _burn(uint256 tokenId) internal virtual {
address owner = ERC721.ownerOf(tokenId);
_beforeTokenTransfer(owner, address(0), tokenId);
// Clear approvals
_approve(address(0), tokenId);
_balances[owner] -= 1;
delete _owners[tokenId];
emit Transfer(owner, address(0), tokenId);
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
* As opposed to {transferFrom}, this imposes no restrictions on msg.sender.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `tokenId` token must be owned by `from`.
*
* Emits a {Transfer} event.
*/
function _transfer(
address from,
address to,
uint256 tokenId
) internal virtual {
require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer of token that is not own");
require(to != address(0), "ERC721: transfer to the zero address");
_beforeTokenTransfer(from, to, tokenId);
// Clear approvals from the previous owner
_approve(address(0), tokenId);
_balances[from] -= 1;
_balances[to] += 1;
_owners[tokenId] = to;
emit Transfer(from, to, tokenId);
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits a {Approval} event.
*/
function _approve(address to, uint256 tokenId) internal virtual {
_tokenApprovals[tokenId] = to;
emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
}
/**
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.
* The call is not executed if the target address is not a contract.
*
* @param from address representing the previous owner of the given token ID
* @param to target address that will receive the tokens
* @param tokenId uint256 ID of the token to be transferred
* @param _data bytes optional data to send along with the call
* @return bool whether the call correctly returned the expected magic value
*/
function _checkOnERC721Received(
address from,
address to,
uint256 tokenId,
bytes memory _data
) private returns (bool) {
if (to.isContract()) {
try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
return retval == IERC721Receiver.onERC721Received.selector;
} catch (bytes memory reason) {
if (reason.length == 0) {
revert("ERC721: transfer to non ERC721Receiver implementer");
} else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
} else {
return true;
}
}
/**
* @dev Hook that is called before any token transfer. This includes minting
* and burning.
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be
* transferred to `to`.
* - When `from` is zero, `tokenId` will be minted for `to`.
* - When `to` is zero, ``from``'s `tokenId` will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 tokenId
) internal virtual {}
}
// File: contracts/Lootlang.sol
pragma solidity ^0.8.7;
// IMPORTS //
/**
* @dev ERC721 token standard
*/
/**
* @dev Modifier 'onlyOwner' becomes available where owner is the contract deployer
*/
/**
* @dev Verification of Merkle trees
*/
/**
* @dev Generates words etc
*/
// LIBRARIES //
/// [MIT License]
/// @title Base64
/// @notice Provides a function for encoding some bytes in base64
/// @author Brecht Devos <[email protected]>
library Base64 {
bytes internal constant TABLE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/// @notice Encodes some bytes to the base64 representation
function encode(bytes memory data) internal pure returns (string memory) {
uint256 len = data.length;
if (len == 0) return "";
// multiply by 4/3 rounded up
uint256 encodedLen = 4 * ((len + 2) / 3);
// Add some extra buffer at the end
bytes memory result = new bytes(encodedLen + 32);
bytes memory table = TABLE;
assembly {
let tablePtr := add(table, 1)
let resultPtr := add(result, 32)
for {
let i := 0
} lt(i, len) {
} {
i := add(i, 3)
let input := and(mload(add(data, i)), 0xffffff)
let out := mload(add(tablePtr, and(shr(18, input), 0x3F)))
out := shl(8, out)
out := add(out, and(mload(add(tablePtr, and(shr(12, input), 0x3F))), 0xFF))
out := shl(8, out)
out := add(out, and(mload(add(tablePtr, and(shr(6, input), 0x3F))), 0xFF))
out := shl(8, out)
out := add(out, and(mload(add(tablePtr, and(input, 0x3F))), 0xFF))
out := shl(224, out)
mstore(resultPtr, out)
resultPtr := add(resultPtr, 4)
}
switch mod(len, 3)
case 1 {
mstore(sub(resultPtr, 2), shl(240, 0x3d3d))
}
case 2 {
mstore(sub(resultPtr, 1), shl(248, 0x3d))
}
mstore(result, encodedLen)
}
return string(result);
}
}
// CONTRACT //
contract Lootlang is ERC721, Ownable, Gen {
// VARIABLES //
uint public enabled;
uint internal mints;
uint internal claims;
uint internal nextTokenId;
uint public contractBalance;
string internal contractURIstring;
uint public freezeBlock;
uint internal freezeBlockChanges;
bytes32 internal root;
constructor() Ownable() ERC721('Lootlang', 'LANG') {
nextTokenId = 1;
freezeBlock = 13487654;
contractURIstring = "https://lootlang.com/metadata.json";
mapChars(); // maps characters to uints
}
// EVENTS //
event Shuffled(uint tokenId);
// ONLY OWNER FUNCTIONS //
/**
* @dev Set the root for Merkle Proof
*/
function setRoot(bytes32 _newRoot) external onlyOwner {
root = _newRoot;
}
/**
* @dev Set the new block number to freeze shuffling. Can only be called once.
*/
function setFreezeBlock(uint _newFreezeBlockNumber) external onlyOwner {
require(freezeBlockChanges < 1, "Freeze block already changed");
freezeBlock = _newFreezeBlockNumber;
freezeBlockChanges++;
}
/**
* @dev Withdraw '_amount' of Ether to address '_to'. Only contract owner can call.
* @param _to - address Ether will be sent to
* @param _amount - amount of Ether, in Wei, to be withdrawn
*/
function withdrawFunds(address payable _to, uint _amount) external onlyOwner {
require(_amount <= contractBalance, "Withdrawal amount greater than balance");
contractBalance -= _amount;
_to.transfer(_amount);
}
/**
* @dev activates/deactivates the minting functionality - only the contract owner can call
* @param _enabled where 1 = enabled and 0 = not
*/
function setEnable(uint _enabled) external onlyOwner {
enabled = _enabled;
}
/**
* @dev Set the contract's URI
* @param _contractURIstring - web address containing data read by OpenSea
*/
function setContractURI(string memory _contractURIstring) external onlyOwner {
contractURIstring = _contractURIstring;
}
// USER FUNCTIONS //
/**
* @dev Mint an ERC721 token.
*/
function mint() external payable {
require(enabled == 1, "Minting is yet to be enabled");
require(nextTokenId <= 10000 && mints <= 9700, "All NFTs have been minted");
require(msg.value >= (2*10**16), "Insufficient funds provided"); // 0.02 eth (cost of minting an NFT) // SET MINT PRICE
mints++;
contractBalance += msg.value;
sharedMintCode();
}
/**
* @dev Claim and mint an ERC721 token.
*/
function claim(bytes32[] memory proof) external {
require(enabled == 1, "Minting is yet to be enabled");
require(hasClaimed[msg.sender] == false, "Already claimed");
require(nextTokenId <= 10000 && claims <= 300, "All NFTs have been minted");
require(MerkleProof.verify(proof, root, keccak256(abi.encodePacked(msg.sender))) == true, "Not on pre-approved claim list");
claims++;
hasClaimed[msg.sender] = true;
sharedMintCode();
}
/**
* @dev Shared code used by both 'mint()' and 'claim()' functions.
*/
function sharedMintCode() internal {
uint tokenId = nextTokenId;
nextTokenId++;
tokenIdToSeed[tokenId] = uint(keccak256(abi.encodePacked(tokenId, msg.sender, block.timestamp)))%1000000;
_safeMint(msg.sender, tokenId);
}
/**
* @dev Shuffles up to 8 words. Set input params as 1 to shuffle word, and 0 to leave it.
* E.g. shuffle(243,1,0,0,0,0,0,0,1) shuffles the 1st and 8th word of token 243.
*/
function shuffle(uint _tokenId, uint one, uint two, uint three, uint four, uint five, uint six, uint seven, uint eight) external {
require(ownerOf(_tokenId) == msg.sender, "Must be NFT owner");
require(shuffleCount[_tokenId] < 5, "Shuffled max amount already");
require(block.number < freezeBlock, "Shuffling has been frozen!");
require((one+two+three+four+five+six+seven+eight) > 0, "No words selected to be shuffled");
uint randomish = uint(keccak256(abi.encodePacked(block.number)))%1000000;
uint[8] memory indexesToChange = [one, two, three, four, five, six, seven, eight];
for (uint i=0; i<8; i++) {
if (indexesToChange[i] > 0) {
tokenIdToShuffleShift[_tokenId][i] += randomish;
}
}
shuffleCount[_tokenId]++;
emit Shuffled(_tokenId);
}
// VIEW FUNCTIONS //
/**
* @dev View total number of minted tokens
*/
function totalSupply() external view returns(uint) {
return mints+claims;
}
/**
* @dev View the contract URI.
*/
function contractURI() public view returns (string memory) {
return contractURIstring;
}
/**
* @dev Internal function used by function 'tokenURI()' to format word lengths for .json file output
*/
function getMetaText(string memory word) internal pure returns(string memory) {
string memory length = string(abi.encodePacked("\"", toString(stringLength(word)), " letters", "\""));
return length;
}
/**
* @dev Internal function used by function 'tokenURI()' to format words for .json file output
*/
function getMetaWord(string memory word) internal pure returns(string memory) {
string memory length = string(abi.encodePacked("\"", word, "\""));
return length;
}
/**
* @dev Creates seed passed in to 'generateWord()' function for seeding randomness
*/
function totalSeedGen(uint tokenId, uint wordNum) internal view returns(uint) {
return uint(keccak256(abi.encodePacked(uint(wordNum), tokenIdToSeed[tokenId], tokenIdToShuffleShift[tokenId][wordNum-1])));
}
/**
* @dev View tokenURI of 'tokenId'.
*/
function tokenURI(uint256 tokenId) override public view returns (string memory) {
require(_exists(tokenId), "URI query for nonexistent token");
string[17] memory parts;
parts[0] = '<svg xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMinYMin meet" viewBox="0 0 350 350"><style>.base { fill: white; font-family: serif; font-size: 20px; }</style><rect width="100%" height="100%" fill="black" /><text x="15" y="30" class="base">';
parts[1] = generateWord(tokenId, totalSeedGen(tokenId, 1));
parts[2] = '</text><text x="15" y="65" class="base">';
parts[3] = generateWord(tokenId, totalSeedGen(tokenId, 2));
parts[4] = '</text><text x="15" y="100" class="base">';
parts[5] = generateWord(tokenId, totalSeedGen(tokenId, 3));
parts[6] = '</text><text x="15" y="135" class="base">';
parts[7] = generateWord(tokenId, totalSeedGen(tokenId, 4));
parts[8] = '</text><text x="15" y="170" class="base">';
parts[9] = generateWord(tokenId, totalSeedGen(tokenId, 5));
parts[10] = '</text><text x="15" y="205" class="base">';
parts[11] = generateWord(tokenId, totalSeedGen(tokenId, 6));
parts[12] = '</text><text x="15" y="240" class="base">';
parts[13] = generateWord(tokenId, totalSeedGen(tokenId, 7));
parts[14] = '</text><text x="15" y="275" class="base">';
parts[15] = generateWord(tokenId, totalSeedGen(tokenId, 8));
parts[16] = '</text></svg>';
string memory output = string(abi.encodePacked(parts[0], parts[1], parts[2], parts[3], parts[4], parts[5], parts[6], parts[7], parts[8]));
output = string(abi.encodePacked(output, parts[9], parts[10], parts[11], parts[12], parts[13], parts[14], parts[15], parts[16]));
string memory json = string(abi.encodePacked('{"name": "Pack #', toString(tokenId), '", "description": "Pack of 8 Lootlang words", "attributes": [{"trait_type": "Shuffles Used", "value":', getMetaWord(toString(shuffleCount[tokenId])), '}, {"trait_type": "Word Length", "value":', getMetaText(parts[1]), '}, {"trait_type": "Word Length", "value":', getMetaText(parts[3]), '}, {"trait_type": "Word Length", "value":', getMetaText(parts[5]), '}, {"trait_type": "Word Length", "value":', getMetaText(parts[7]), '}, {"trait_type": "Word Length", "value":', getMetaText(parts[9]), '}, {"trait_type": "Word Length", "value":', getMetaText(parts[11]), '}, {"trait_type": "Word Length", "value":', getMetaText(parts[13]), '}, {"trait_type": "Word Length", "value":', getMetaText(parts[15]), '}'));
json = Base64.encode(bytes(string(abi.encodePacked(json, ', {"trait_type": "Word", "value":', getMetaWord(parts[1]), '}, {"trait_type": "Word", "value":', getMetaWord(parts[3]), '}, {"trait_type": "Word", "value":', getMetaWord(parts[5]), '}, {"trait_type": "Word", "value":', getMetaWord(parts[7]), '}, {"trait_type": "Word", "value":', getMetaWord(parts[9]), '}, {"trait_type": "Word", "value":', getMetaWord(parts[11]), '}, {"trait_type": "Word", "value":', getMetaWord(parts[13]), '}, {"trait_type": "Word", "value":', getMetaWord(parts[15]), '}], "image": "data:image/svg+xml;base64, ', Base64.encode(bytes(output)), '"}'))));
output = string(abi.encodePacked('data:application/json;base64,', json));
return output;
}
}