Contract Source Code:
File 1 of 1 : Howl
// File: @openzeppelin/contracts/utils/cryptography/ECDSA.sol
pragma solidity ^0.8.0;
/**
* @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
*
* These functions can be used to verify that a message was signed by the holder
* of the private keys of a given address.
*/
library ECDSA {
enum RecoverError {
NoError,
InvalidSignature,
InvalidSignatureLength,
InvalidSignatureS,
InvalidSignatureV
}
function _throwError(RecoverError error) private pure {
if (error == RecoverError.NoError) {
return; // no error: do nothing
} else if (error == RecoverError.InvalidSignature) {
revert("ECDSA: invalid signature");
} else if (error == RecoverError.InvalidSignatureLength) {
revert("ECDSA: invalid signature length");
} else if (error == RecoverError.InvalidSignatureS) {
revert("ECDSA: invalid signature 's' value");
} else if (error == RecoverError.InvalidSignatureV) {
revert("ECDSA: invalid signature 'v' value");
}
}
/**
* @dev Returns the address that signed a hashed message (`hash`) with
* `signature` or error string. This address can then be used for verification purposes.
*
* The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
* this function rejects them by requiring the `s` value to be in the lower
* half order, and the `v` value to be either 27 or 28.
*
* IMPORTANT: `hash` _must_ be the result of a hash operation for the
* verification to be secure: it is possible to craft signatures that
* recover to arbitrary addresses for non-hashed data. A safe way to ensure
* this is by receiving a hash of the original message (which may otherwise
* be too long), and then calling {toEthSignedMessageHash} on it.
*
* Documentation for signature generation:
* - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
* - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
*
* _Available since v4.3._
*/
function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
// Check the signature length
// - case 65: r,s,v signature (standard)
// - case 64: r,vs signature (cf https://eips.ethereum.org/EIPS/eip-2098) _Available since v4.1._
if (signature.length == 65) {
bytes32 r;
bytes32 s;
uint8 v;
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
assembly {
r := mload(add(signature, 0x20))
s := mload(add(signature, 0x40))
v := byte(0, mload(add(signature, 0x60)))
}
return tryRecover(hash, v, r, s);
} else if (signature.length == 64) {
bytes32 r;
bytes32 vs;
// ecrecover takes the signature parameters, and the only way to get them
// currently is to use assembly.
assembly {
r := mload(add(signature, 0x20))
vs := mload(add(signature, 0x40))
}
return tryRecover(hash, r, vs);
} else {
return (address(0), RecoverError.InvalidSignatureLength);
}
}
/**
* @dev Returns the address that signed a hashed message (`hash`) with
* `signature`. This address can then be used for verification purposes.
*
* The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
* this function rejects them by requiring the `s` value to be in the lower
* half order, and the `v` value to be either 27 or 28.
*
* IMPORTANT: `hash` _must_ be the result of a hash operation for the
* verification to be secure: it is possible to craft signatures that
* recover to arbitrary addresses for non-hashed data. A safe way to ensure
* this is by receiving a hash of the original message (which may otherwise
* be too long), and then calling {toEthSignedMessageHash} on it.
*/
function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
(address recovered, RecoverError error) = tryRecover(hash, signature);
_throwError(error);
return recovered;
}
/**
* @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
*
* See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
*
* _Available since v4.3._
*/
function tryRecover(
bytes32 hash,
bytes32 r,
bytes32 vs
) internal pure returns (address, RecoverError) {
bytes32 s;
uint8 v;
assembly {
s := and(vs, 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff)
v := add(shr(255, vs), 27)
}
return tryRecover(hash, v, r, s);
}
/**
* @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
*
* _Available since v4.2._
*/
function recover(
bytes32 hash,
bytes32 r,
bytes32 vs
) internal pure returns (address) {
(address recovered, RecoverError error) = tryRecover(hash, r, vs);
_throwError(error);
return recovered;
}
/**
* @dev Overload of {ECDSA-tryRecover} that receives the `v`,
* `r` and `s` signature fields separately.
*
* _Available since v4.3._
*/
function tryRecover(
bytes32 hash,
uint8 v,
bytes32 r,
bytes32 s
) internal pure returns (address, RecoverError) {
// EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
// unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
// the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
// signatures from current libraries generate a unique signature with an s-value in the lower half order.
//
// If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
// with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
// vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
// these malleable signatures as well.
if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
return (address(0), RecoverError.InvalidSignatureS);
}
if (v != 27 && v != 28) {
return (address(0), RecoverError.InvalidSignatureV);
}
// If the signature is valid (and not malleable), return the signer address
address signer = ecrecover(hash, v, r, s);
if (signer == address(0)) {
return (address(0), RecoverError.InvalidSignature);
}
return (signer, RecoverError.NoError);
}
/**
* @dev Overload of {ECDSA-recover} that receives the `v`,
* `r` and `s` signature fields separately.
*/
function recover(
bytes32 hash,
uint8 v,
bytes32 r,
bytes32 s
) internal pure returns (address) {
(address recovered, RecoverError error) = tryRecover(hash, v, r, s);
_throwError(error);
return recovered;
}
/**
* @dev Returns an Ethereum Signed Message, created from a `hash`. This
* produces hash corresponding to the one signed with the
* https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
* JSON-RPC method as part of EIP-191.
*
* See {recover}.
*/
function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
// 32 is the length in bytes of hash,
// enforced by the type signature above
return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
}
/**
* @dev Returns an Ethereum Signed Typed Data, created from a
* `domainSeparator` and a `structHash`. This produces hash corresponding
* to the one signed with the
* https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
* JSON-RPC method as part of EIP-712.
*
* See {recover}.
*/
function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
}
}
// File: @openzeppelin/contracts/utils/Counters.sol
pragma solidity ^0.8.0;
/**
* @title Counters
* @author Matt Condon (@shrugs)
* @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
* of elements in a mapping, issuing ERC721 ids, or counting request ids.
*
* Include with `using Counters for Counters.Counter;`
*/
library Counters {
struct Counter {
// This variable should never be directly accessed by users of the library: interactions must be restricted to
// the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
// this feature: see https://github.com/ethereum/solidity/issues/4637
uint256 _value; // default: 0
}
function current(Counter storage counter) internal view returns (uint256) {
return counter._value;
}
function increment(Counter storage counter) internal {
unchecked {
counter._value += 1;
}
}
function decrement(Counter storage counter) internal {
uint256 value = counter._value;
require(value > 0, "Counter: decrement overflow");
unchecked {
counter._value = value - 1;
}
}
function reset(Counter storage counter) internal {
counter._value = 0;
}
}
// 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/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/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/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/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/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/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: @openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol
pragma solidity ^0.8.0;
/**
* @title ERC721 Burnable Token
* @dev ERC721 Token that can be irreversibly burned (destroyed).
*/
abstract contract ERC721Burnable is Context, ERC721 {
/**
* @dev Burns `tokenId`. See {ERC721-_burn}.
*
* Requirements:
*
* - The caller must own `tokenId` or be an approved operator.
*/
function burn(uint256 tokenId) public virtual {
//solhint-disable-next-line max-line-length
require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721Burnable: caller is not owner nor approved");
_burn(tokenId);
}
}
// File: contracts/Howl.sol
pragma solidity ^0.8.2;
interface ISoul {
function mint(address _address, uint256 _amount) external;
function collectAndBurn(address _address, uint256 _amount) external;
}
contract Howl is ERC721Burnable, Ownable {
using ECDSA for bytes32;
using Counters for Counters.Counter;
constructor() ERC721("House of Warlords", "HOWL") Ownable() {
genesisTokenIdCounter._value = 888; // accounting for giveaways and reserve
genesisReserveTokenIdCounter._value = 8; // accounting for legendaries
}
struct Warlord {
uint16 face; // 0
uint16 headGear; // 1
uint16 clothes; // 2
uint16 shoulderGuard; // 3
uint16 armGuards; // 4
uint16 sideWeapon; // 5
uint16 backWeapon; // 6
uint16 background; // 7
uint16 killCount; // 8
}
event Seppuku(
address indexed _address,
uint256 indexed _generation,
uint256 _tokenId1,
uint256 _tokenId2
);
event Resurrection(
uint256 indexed _tokenId,
address indexed _address,
uint256 indexed _generation
);
event VoucherUsed(
address indexed _address,
uint256 indexed _nonce,
uint256 _claimQty
);
event StartConquest(uint256 indexed _tokenId, uint256 _startDate);
event EndConquest(uint256 indexed _tokenId, uint256 _reward);
event NameChange(uint256 indexed _tokenId, string _name);
Counters.Counter public generationCounter;
Counters.Counter public genesisTokenIdCounter;
Counters.Counter public genesisReserveTokenIdCounter;
uint256 public constant GENESIS_MAX_SUPPLY = 8888;
uint256 public constant RESERVE_QTY = 888;
uint256 public SALE_MINT_PRICE = 0.069 ether;
bool public IS_SALE_ON;
bool public IS_SEPPUKU_ON;
bool public IS_STAKING_ON;
uint256[3] private _stakingRewards = [250, 600, 1000];
uint256[3] private _stakingPeriods = [30, 60, 90];
uint256 public seppukuBaseFee = 1000;
uint256 public seppukuMultiplierFee = 500;
bool public canSummonLegendaries = true;
string public preRevealUrl;
string public apiUrl;
address public signer;
address public soulContractAddress;
// When warlords are minted for the first time this contract generates a random looking DNA mapped to a tokenID.
// The actual uint16 properties of the warlord are later derived by decoding it with the
// information that's inside of the generationRanges and generationRarities mappings.
// Each generation of warlords will have its own set of rarities and property ranges
// with a provenance hash uploaded ahead of time.
// It gurantees that the actual property distribution is hidden during the pre-reveal phase since decoding depends on
// the unknown information.
// Property ranges are stored inside of a uint16[4] array per each property.
// These 4 numbers are interpreted as buckets of traits. Traits are just sequential numbers.
// For example [1, 100, 200, 300] value inside of generationRanges for the face property will be interpreted as:
// - Common: 1-99
// - Uncommon: 100-199
// - Rare: 200 - 299
//
// The last two pieces of data are located inside of generationRarities mapping which holds uint16[2] arrays of rarities.
// For example, if our rarities were defined as [80, 15], combined with buckets from above they will result in:
// - Common: 1-99 [80% chance]
// - Uncommon: 100-199 [15% chance]
// - Rare: 200 - 299 [5% chance]
//
// This framework helps us to keep our trait generation random and hidden while still allowing for
// clearly defined rarity categories.
mapping(uint256 => mapping(uint256 => uint16[4])) public generationRanges;
mapping(uint256 => uint16[2]) public generationRarities;
mapping(uint256 => uint256) public generationProvenance;
mapping(uint256 => bool) public isGenerationRevealed;
mapping(uint256 => uint256) public generationSeed;
mapping(uint256 => uint256) public generationResurrectionChance;
mapping(address => mapping(uint256 => uint256)) public resurrectionTickets;
mapping(uint256 => uint256) private _tokenIdToWarlord;
mapping(uint256 => uint256) public conquests;
mapping(uint256 => uint256) private _voucherToMinted;
mapping(uint256 => string) public tokenIdToWarlordName;
mapping(string => bool) public namesTaken;
// This mapping is going to be used to connect our howl store implementation and potential future
// mechanics that will enhance this collection.
mapping(address => bool) public authorizedToEquip;
// Kill switch for the mapping above, if community decides that it's too dangerous to have this
// list extendable we can prevent it from being modified.
bool public isAuthorizedToEquipLocked;
mapping(address => bool) public admins;
function _isTokenOwner(uint256 _tokenId) private view {
require(
ownerOf(_tokenId) == msg.sender,
"HOWL: you don't own this token"
);
}
function _isOwnerOrAdmin() private view {
require(
owner() == msg.sender || admins[msg.sender],
"HOWL: unauthorized"
);
}
modifier onlyOwnerOrAdmin() {
_isOwnerOrAdmin();
_;
}
modifier onlyTokenOwner(uint256 _tokenId) {
_isTokenOwner(_tokenId);
_;
}
modifier onlyAuthorizedToEquip() {
require(authorizedToEquip[msg.sender], "HOWL: unauthorized");
_;
}
function withdraw() external onlyOwner {
payable(owner()).transfer(address(this).balance);
}
function setAuthorizedToEquip(address _address, bool _isAuthorized)
external
onlyOwner
{
require(!isAuthorizedToEquipLocked);
authorizedToEquip[_address] = _isAuthorized;
}
function lockAuthorizedToEquip() external onlyOwner {
isAuthorizedToEquipLocked = true;
}
function setAdmin(address _address, bool _hasAccess) external onlyOwner {
admins[_address] = _hasAccess;
}
function setSaleMintPrice(uint256 _mintPrice) external onlyOwner {
SALE_MINT_PRICE = _mintPrice;
}
function setSigner(address _signer) external onlyOwner {
signer = _signer;
}
function setApiUrl(string calldata _apiUrl) external onlyOwner {
apiUrl = _apiUrl;
}
function setPreRevealUrl(string calldata _preRevealUrl) external onlyOwner {
preRevealUrl = _preRevealUrl;
}
function setSoulContractAddress(address _address) external onlyOwner {
soulContractAddress = _address;
}
function setIsSaleOn(bool _isSaleOn) external onlyOwnerOrAdmin {
IS_SALE_ON = _isSaleOn;
}
function setIsSeppukuOn(bool _isSeppukuOn) external onlyOwnerOrAdmin {
IS_SEPPUKU_ON = _isSeppukuOn;
}
function setSeppukuBaseAndMultiplierFee(
uint256 _baseFee,
uint256 _multiplierFee
) external onlyOwnerOrAdmin {
seppukuBaseFee = _baseFee;
seppukuMultiplierFee = _multiplierFee;
}
function setStakingRewardsAndPeriods(
uint256[3] calldata _rewards,
uint256[3] calldata _periods
) external onlyOwnerOrAdmin {
_stakingRewards = _rewards;
_stakingPeriods = _periods;
}
function getStakingRewardsAndPeriods()
external
view
returns (uint256[3][2] memory)
{
return [
[_stakingRewards[0], _stakingRewards[1], _stakingRewards[2]],
[_stakingPeriods[0], _stakingPeriods[1], _stakingPeriods[2]]
];
}
function setIsStakingOn(bool _isStakingOn) external onlyOwnerOrAdmin {
IS_STAKING_ON = _isStakingOn;
}
function setIsGenerationRevealed(uint256 _gen, bool _isGenerationRevealed)
external
onlyOwnerOrAdmin
{
require(!isGenerationRevealed[_gen]);
isGenerationRevealed[_gen] = _isGenerationRevealed;
}
function setGenerationRanges(
uint256 _gen,
uint16[4] calldata _face,
uint16[4] calldata _headGear,
uint16[4] calldata _clothes,
uint16[4] calldata _shoulderGuard,
uint16[4] calldata _armGuards,
uint16[4] calldata _sideWeapon,
uint16[4] calldata _backWeapon,
uint16[4] calldata _background
) external onlyOwnerOrAdmin {
require(!isGenerationRevealed[_gen]);
generationRanges[_gen][0] = _face;
generationRanges[_gen][1] = _headGear;
generationRanges[_gen][2] = _clothes;
generationRanges[_gen][3] = _shoulderGuard;
generationRanges[_gen][4] = _armGuards;
generationRanges[_gen][5] = _sideWeapon;
generationRanges[_gen][6] = _backWeapon;
generationRanges[_gen][7] = _background;
}
function setGenerationRarities(
uint256 _gen,
uint16 _common,
uint16 _uncommon
) external onlyOwnerOrAdmin {
require(!isGenerationRevealed[_gen]);
// rare is derived by 100% - common + uncommon
// so in the case of [80,15] - rare will be 5%
require(_common > _uncommon);
generationRarities[_gen] = [_common, _uncommon];
}
function setGenerationProvenance(uint256 _provenance, uint256 _gen)
external
onlyOwnerOrAdmin
{
require(generationProvenance[_gen] == 0);
generationProvenance[_gen] = _provenance;
}
function startNextGenerationResurrection(uint256 _resurrectionChance)
external
onlyOwnerOrAdmin
{
require(!IS_SEPPUKU_ON);
generationCounter.increment();
uint256 gen = generationCounter.current();
generationSeed[gen] = _getSeed();
generationResurrectionChance[gen] = _resurrectionChance;
}
function mintReserve(address _address, uint256 _claimQty)
external
onlyOwner
{
require(
genesisReserveTokenIdCounter.current() + _claimQty <= RESERVE_QTY
);
for (uint256 i = 0; i < _claimQty; i++) {
genesisReserveTokenIdCounter.increment();
_mintWarlord(_address, genesisReserveTokenIdCounter.current(), 0);
}
}
function summonLegendaries(address _address) external onlyOwner {
require(canSummonLegendaries);
// make sure that this action cannot be performed again
// in theory all 10 legendaries can be burned
canSummonLegendaries = false;
uint256 traitBase = 10000;
for (uint256 i = 1; i < 9; i++) {
// first 4 are zen, second 4 are aku
_tokenIdToWarlord[i] = _generateDecodedDna(
Warlord(
uint16(traitBase + i), // produces traits that look like 10001 - 10002 - ...etc.
uint16(traitBase + i),
uint16(traitBase + i),
uint16(traitBase + i),
uint16(traitBase + i),
uint16(traitBase + i),
uint16(traitBase + i),
(i <= 4) ? uint16(traitBase + 1) : uint16(traitBase + 2), // background is 10001 for zen and 10002 for aku
0 // 0 kills
)
);
_safeMint(_address, i);
}
}
function redeemVoucher(
address _address,
uint256 _approvedQty,
uint256 _price,
uint256 _nonce,
bool _isLastItemFree,
bool _isTeamReserve,
uint256 _claimQty,
bytes calldata _voucher
) external payable {
bytes32 hash = keccak256(
abi.encodePacked(
_address,
_approvedQty,
_price,
_nonce,
_isLastItemFree,
_isTeamReserve
)
);
require(
_verifySignature(signer, hash, _voucher),
"HOWL: invalid signature"
);
uint256 totalWithClaimed = _voucherToMinted[uint256(hash)] + _claimQty;
require(totalWithClaimed <= _approvedQty, "HOWL: exceeds approved qty");
_voucherToMinted[uint256(hash)] += _claimQty;
// Make last item free if voucher allows
string memory err = "HOWL: not enough funds sent";
if (totalWithClaimed == _approvedQty && _isLastItemFree) {
require(msg.value >= _price * (_claimQty - 1), err);
} else {
require(msg.value >= _price * _claimQty, err);
}
if (_isTeamReserve) {
// Minting from 9-888 range if authorized to mint from the reserve
require(
genesisReserveTokenIdCounter.current() + _claimQty <=
RESERVE_QTY,
"HOWL: exceeds reserve supply"
);
for (uint256 i = 0; i < _claimQty; i++) {
genesisReserveTokenIdCounter.increment();
_mintWarlord(
_address,
genesisReserveTokenIdCounter.current(),
0
);
}
} else {
// minting from 889 to 8888
require(
genesisTokenIdCounter.current() + _claimQty <=
GENESIS_MAX_SUPPLY,
"HOWL: exceeds max genesis supply"
);
for (uint256 i = 0; i < _claimQty; i++) {
genesisTokenIdCounter.increment();
_mintWarlord(_address, genesisTokenIdCounter.current(), 0);
}
}
emit VoucherUsed(_address, _nonce, _claimQty);
}
function mintSale(uint256 _claimQty) external payable {
require(IS_SALE_ON, "HOWL: sale is not active");
require(
_claimQty <= 10,
"HOWL: can't claim more than 10 in one transaction"
);
require(
msg.value >= SALE_MINT_PRICE * _claimQty,
"HOWL: not enough funds sent"
);
require(
genesisTokenIdCounter.current() + _claimQty <= GENESIS_MAX_SUPPLY,
"HOWL: exceeds max genesis supply"
);
for (uint256 i = 0; i < _claimQty; i++) {
genesisTokenIdCounter.increment();
_mintWarlord(msg.sender, genesisTokenIdCounter.current(), 0);
}
}
function _mintWarlord(
address _address,
uint256 _tokenId,
uint256 _gen
) private {
uint256 dna = uint256(
keccak256(abi.encodePacked(_address, _tokenId, _getSeed()))
);
// When warlords are generated for the first time
// the last 9 bits of their DNA will be used to store the generation number (8 bit)
// and a flag that indicates whether the dna is in its encoded
// or decoded state (1 bit).
// Generation number will help to properly decode properties based on
// property ranges that are unknown during minting.
// ((dna >> 9) << 9) clears the last 9 bits.
// _gen * 2 moves generation information one bit to the left and sets the last bit to 0.
dna = ((dna >> 9) << 9) | (uint8(_gen) * 2);
_tokenIdToWarlord[_tokenId] = dna;
_safeMint(_address, _tokenId);
}
function canResurrectWarlord(address _address, uint256 _tokenId)
public
view
returns (bool)
{
// Check if resurrection ticket was submitted
uint256 currentGen = generationCounter.current();
uint256 resurrectionGen = resurrectionTickets[_address][_tokenId];
if (resurrectionGen == 0 || resurrectionGen != currentGen) {
return false;
}
// Check if current generation was seeded
uint256 seed = generationSeed[currentGen];
if (seed == 0) {
return false;
}
// Check if this token is lucky to be reborn
if (
(uint256(keccak256(abi.encodePacked(_tokenId, seed))) % 100) >
generationResurrectionChance[currentGen]
) {
return false;
}
return true;
}
function resurrectWarlord(uint256 _tokenId) external {
require(
canResurrectWarlord(msg.sender, _tokenId),
"HOWL: warlord cannot be resurrected"
);
delete resurrectionTickets[msg.sender][_tokenId];
uint256 gen = generationCounter.current();
_mintWarlord(msg.sender, _tokenId, gen);
emit Resurrection(_tokenId, msg.sender, gen);
}
function seppuku(
uint256 _tokenId1,
uint256 _tokenId2,
uint16[8] calldata _w
) external onlyTokenOwner(_tokenId1) onlyTokenOwner(_tokenId2) {
require(
soulContractAddress != address(0) && IS_SEPPUKU_ON,
"HOWL: seppuku is not active"
);
Warlord memory w1 = getWarlord(_tokenId1);
Warlord memory w2 = getWarlord(_tokenId2);
require(
(_w[0] == w1.face || _w[0] == w2.face) &&
(_w[1] == w1.headGear || _w[1] == w2.headGear) &&
(_w[2] == w1.clothes || _w[2] == w2.clothes) &&
(_w[3] == w1.shoulderGuard || _w[3] == w2.shoulderGuard) &&
(_w[4] == w1.armGuards || _w[4] == w2.armGuards) &&
(_w[5] == w1.sideWeapon || _w[5] == w2.sideWeapon) &&
(_w[6] == w1.backWeapon || _w[6] == w2.backWeapon) &&
(_w[7] == w1.background || _w[7] == w2.background),
"HOWL: invalid property transfer"
);
_burn(_tokenId2);
ISoul(soulContractAddress).mint(
msg.sender,
seppukuBaseFee +
((w1.killCount + w2.killCount) * seppukuMultiplierFee)
);
// Once any composability mechanic is used warlord traits become fully decoded
// for the ease of future trait transfers between generations.
_tokenIdToWarlord[_tokenId1] = _generateDecodedDna(
Warlord(
_w[0],
_w[1],
_w[2],
_w[3],
_w[4],
_w[5],
_w[6],
_w[7],
w1.killCount + w2.killCount + 1
)
);
uint256 gen = generationCounter.current();
// Burned token has a chance of resurrection during the next generation.
resurrectionTickets[msg.sender][_tokenId2] = gen + 1;
emit Seppuku(msg.sender, gen, _tokenId1, _tokenId2);
}
function equipProperties(
address _originalCaller,
uint256 _tokenId,
uint16[8] calldata _w
) external onlyAuthorizedToEquip {
require(
ownerOf(_tokenId) == _originalCaller,
"HOWL: you don't own this token"
);
Warlord memory w = getWarlord(_tokenId);
w.face = _w[0] == 0 ? w.face : _w[0];
w.headGear = _w[1] == 0 ? w.headGear : _w[1];
w.clothes = _w[2] == 0 ? w.clothes : _w[2];
w.shoulderGuard = _w[3] == 0 ? w.shoulderGuard : _w[3];
w.armGuards = _w[4] == 0 ? w.armGuards : _w[4];
w.sideWeapon = _w[5] == 0 ? w.sideWeapon : _w[5];
w.backWeapon = _w[6] == 0 ? w.backWeapon : _w[6];
w.background = _w[7] == 0 ? w.background : _w[7];
_tokenIdToWarlord[_tokenId] = _generateDecodedDna(w);
}
function startConquest(uint256 _tokenId) external onlyTokenOwner(_tokenId) {
require(IS_STAKING_ON, "HOWL: conquests are disabled");
require(
conquests[_tokenId] == 0,
"HOWL: current conquest hasn't ended yet"
);
conquests[_tokenId] = block.timestamp;
emit StartConquest(_tokenId, block.timestamp);
}
function getCurrentConquestReward(uint256 _tokenId)
public
view
returns (uint256)
{
uint256 conquestStart = conquests[_tokenId];
require(conquestStart != 0, "HOWL: warlord is not on a conquest");
// Calculate for how long the token has been staked
uint256 stakedDays = (block.timestamp - conquestStart) / 24 / 60 / 60;
uint256[3] memory periods = _stakingPeriods;
uint256[3] memory rewards = _stakingRewards;
if (stakedDays >= periods[2]) {
return rewards[2];
} else if (stakedDays >= periods[1]) {
return rewards[1];
} else if (stakedDays >= periods[0]) {
return rewards[0];
}
return 0;
}
function endConquest(uint256 _tokenId) external onlyTokenOwner(_tokenId) {
uint256 reward = getCurrentConquestReward(_tokenId);
delete conquests[_tokenId];
if (reward != 0) {
ISoul(soulContractAddress).mint(msg.sender, reward);
}
emit EndConquest(_tokenId, reward);
}
// Tokens can't be transferred when on a conquest
function _beforeTokenTransfer(
address from,
address to,
uint256 tokenId
) internal view override {
require(
conquests[tokenId] == 0,
"HOWL: can't transfer or burn warlord while on a conquest"
);
}
function nameWarlord(uint256 _tokenId, string calldata _name)
external
onlyTokenOwner(_tokenId)
{
require(!namesTaken[_name], "HOWL: this name has been taken");
ISoul(soulContractAddress).collectAndBurn(msg.sender, 250);
// if warlords was renamed - unreserve the previous name
string memory previousName = tokenIdToWarlordName[_tokenId];
if (bytes(previousName).length > 0) {
namesTaken[previousName] = false;
}
tokenIdToWarlordName[_tokenId] = _name;
if (bytes(_name).length > 0) {
namesTaken[_name] = true;
}
emit NameChange(_tokenId, _name);
}
function tokenURI(uint256 _tokenId)
public
view
override
returns (string memory)
{
require(_exists(_tokenId), "HOWL: warlord doesn't exist");
if (
bytes(apiUrl).length == 0 ||
!_isDnaRevealed(_tokenIdToWarlord[_tokenId])
) {
return preRevealUrl;
}
Warlord memory w = getWarlord(_tokenId);
string memory separator = "-";
return
string(
abi.encodePacked(
apiUrl,
abi.encodePacked(
_toString(_tokenId),
separator,
_toString(w.face),
separator,
_toString(w.headGear),
separator,
_toString(w.clothes)
),
abi.encodePacked(
separator,
_toString(w.shoulderGuard),
separator,
_toString(w.armGuards),
separator,
_toString(w.sideWeapon)
),
abi.encodePacked(
separator,
_toString(w.backWeapon),
separator,
_toString(w.background),
separator,
_toString(w.killCount)
)
)
);
}
function _verifySignature(
address _signer,
bytes32 _hash,
bytes memory _signature
) private pure returns (bool) {
return
_signer ==
ECDSA.recover(ECDSA.toEthSignedMessageHash(_hash), _signature);
}
function _getSeed() private view returns (uint256) {
return uint256(blockhash(block.number - 1));
}
function _generateDecodedDna(Warlord memory _w)
private
pure
returns (uint256)
{
uint256 dna = _w.killCount; // 8
dna = (dna << 16) | _w.background; // 7
dna = (dna << 16) | _w.backWeapon; // 6
dna = (dna << 16) | _w.sideWeapon; // 5
dna = (dna << 16) | _w.armGuards; // 4
dna = (dna << 16) | _w.shoulderGuard; // 3
dna = (dna << 16) | _w.clothes; // 2
dna = (dna << 16) | _w.headGear; // 1
dna = (dna << 16) | _w.face; // 0
dna = (dna << 1) | 1; // flag indicating whether this dna was decoded
// Decoded DNA won't have a generation number anymore.
// These traits will permanently look decoded and no further manipulation will be needed
// apart from just extracting it with a bitshift.
return dna;
}
function _isDnaRevealed(uint256 _dna) private view returns (bool) {
// Check the last bit to see if dna is decoded.
if (_dna & 1 == 1) {
return true;
}
// If dna wasn't decoded we wanna look up whether the generation it belongs to was revealed.
return isGenerationRevealed[(_dna >> 1) & 0xFF];
}
function getWarlord(uint256 _tokenId) public view returns (Warlord memory) {
uint256 dna = _tokenIdToWarlord[_tokenId];
require(_isDnaRevealed(dna), "HOWL: warlord is not revealed yet");
Warlord memory w;
w.face = _getWarlordProperty(dna, 0);
w.headGear = _getWarlordProperty(dna, 1);
w.clothes = _getWarlordProperty(dna, 2);
w.shoulderGuard = _getWarlordProperty(dna, 3);
w.armGuards = _getWarlordProperty(dna, 4);
w.sideWeapon = _getWarlordProperty(dna, 5);
w.backWeapon = _getWarlordProperty(dna, 6);
w.background = _getWarlordProperty(dna, 7);
w.killCount = _getWarlordProperty(dna, 8);
return w;
}
function _getWarlordProperty(uint256 _dna, uint256 _propertyId)
private
view
returns (uint16)
{
// Property right offset in bits.
uint256 bitShift = _propertyId * 16;
// Last bit shows whether the dna was already decoded.
// If it was we can safely return the stored value after bitshifting and applying a mask.
// Decoded values don't have a generation number, so only need to shift by one bit to account for the flag.
if (_dna & 1 == 1) {
return uint16(((_dna >> 1) >> bitShift) & 0xFFFF);
}
// Every time warlords commit seppuku their DNA will be decoded.
// If we got here it means that it wasn't decoded and we can safely assume that their kill counter is 0.
if (_propertyId == 8) {
return 0;
}
// Minted generation number is stored inside of 8 bits after the encoded/decoded flag.
uint256 gen = (_dna >> 1) & 0xFF;
// Rarity and range values to decode the property (specific to generation)
uint16[2] storage _rarity = generationRarities[gen];
uint16[4] storage _range = generationRanges[gen][_propertyId];
// Extracting the encoded (raw) property (also shifting by 9bits first to account for generation metadata and a flag).
// This property is just a raw value, it will get decoded with _rarity and _range information from above.
uint256 encodedProp = (((_dna >> 9) >> bitShift) & 0xFFFF);
if (
(_propertyId == 3 || _propertyId == 4 || _propertyId == 5) &&
// 60% chance that sideWeapon/armGuards/shoulderGuard will appear
uint256(keccak256(abi.encodePacked(encodedProp, _range))) % 100 > 60
) {
// Unlucky
return 0;
}
// A value that will dictate from which pool of properties we should pull (common, uncommon, rare)
uint256 rarityDecider = (uint256(
keccak256(abi.encodePacked(_propertyId, _dna, _range))
) % 100) + 1;
uint256 rangeStart;
uint256 rangeEnd;
// There is an opportunity to optimize for SLOAD operations here by byte packing all
// rarity/range information and loading it in getWarlord before this function
// is called to minimize state access.
if (rarityDecider <= _rarity[0]) {
// common
rangeStart = _range[0];
rangeEnd = _range[1];
} else if (rarityDecider <= _rarity[1] + _rarity[0]) {
// uncommon
rangeStart = _range[1];
rangeEnd = _range[2];
} else {
// rare
rangeStart = _range[2];
rangeEnd = _range[3];
}
// Returns a decoded property that will fall within one of the rarity buckets.
return uint16((encodedProp % (rangeEnd - rangeStart)) + rangeStart);
}
function _toString(uint256 value) internal pure returns (string memory) {
// Inspired by OraclizeAPI's implementation - MIT license
// 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);
}
}