Contract Source Code:
File 1 of 1 : BearRiders
//SPDX-License-Identifier: MIT
// File: @openzeppelin/contracts/utils/Address.sol
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)
pragma solidity ^0.8.1;
/**
* @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
* ====
*
* [IMPORTANT]
* ====
* You shouldn't rely on `isContract` to protect against flash loan attacks!
*
* Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
* like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
* constructor.
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize/address.code.length, which returns 0
// for contracts in construction, since the code is only stored at the end
// of the constructor execution.
return account.code.length > 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
// OpenZeppelin Contracts v4.4.1 (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
// OpenZeppelin Contracts v4.4.1 (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
// OpenZeppelin Contracts v4.4.1 (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
// OpenZeppelin Contracts v4.4.1 (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
// OpenZeppelin Contracts v4.4.1 (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/utils/math/Math.sol
// OpenZeppelin Contracts (last updated v4.7.0) (utils/math/Math.sol)
pragma solidity ^0.8.0;
/**
* @dev Standard math utilities missing in the Solidity language.
*/
library Math {
enum Rounding {
Down, // Toward negative infinity
Up, // Toward infinity
Zero // Toward zero
}
/**
* @dev Returns the largest of two numbers.
*/
function max(uint256 a, uint256 b) internal pure returns (uint256) {
return a >= b ? a : b;
}
/**
* @dev Returns the smallest of two numbers.
*/
function min(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two numbers. The result is rounded towards
* zero.
*/
function average(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b) / 2 can overflow.
return (a & b) + (a ^ b) / 2;
}
/**
* @dev Returns the ceiling of the division of two numbers.
*
* This differs from standard division with `/` in that it rounds up instead
* of rounding down.
*/
function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b - 1) / b can overflow on addition, so we distribute.
return a == 0 ? 0 : (a - 1) / b + 1;
}
/**
* @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
* @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
* with further edits by Uniswap Labs also under MIT license.
*/
function mulDiv(
uint256 x,
uint256 y,
uint256 denominator
) internal pure returns (uint256 result) {
unchecked {
// 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
// use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
// variables such that product = prod1 * 2^256 + prod0.
uint256 prod0; // Least significant 256 bits of the product
uint256 prod1; // Most significant 256 bits of the product
assembly {
let mm := mulmod(x, y, not(0))
prod0 := mul(x, y)
prod1 := sub(sub(mm, prod0), lt(mm, prod0))
}
// Handle non-overflow cases, 256 by 256 division.
if (prod1 == 0) {
return prod0 / denominator;
}
// Make sure the result is less than 2^256. Also prevents denominator == 0.
require(denominator > prod1);
///////////////////////////////////////////////
// 512 by 256 division.
///////////////////////////////////////////////
// Make division exact by subtracting the remainder from [prod1 prod0].
uint256 remainder;
assembly {
// Compute remainder using mulmod.
remainder := mulmod(x, y, denominator)
// Subtract 256 bit number from 512 bit number.
prod1 := sub(prod1, gt(remainder, prod0))
prod0 := sub(prod0, remainder)
}
// Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
// See https://cs.stackexchange.com/q/138556/92363.
// Does not overflow because the denominator cannot be zero at this stage in the function.
uint256 twos = denominator & (~denominator + 1);
assembly {
// Divide denominator by twos.
denominator := div(denominator, twos)
// Divide [prod1 prod0] by twos.
prod0 := div(prod0, twos)
// Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
twos := add(div(sub(0, twos), twos), 1)
}
// Shift in bits from prod1 into prod0.
prod0 |= prod1 * twos;
// Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
// that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
// four bits. That is, denominator * inv = 1 mod 2^4.
uint256 inverse = (3 * denominator) ^ 2;
// Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
// in modular arithmetic, doubling the correct bits in each step.
inverse *= 2 - denominator * inverse; // inverse mod 2^8
inverse *= 2 - denominator * inverse; // inverse mod 2^16
inverse *= 2 - denominator * inverse; // inverse mod 2^32
inverse *= 2 - denominator * inverse; // inverse mod 2^64
inverse *= 2 - denominator * inverse; // inverse mod 2^128
inverse *= 2 - denominator * inverse; // inverse mod 2^256
// Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
// This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
// less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
// is no longer required.
result = prod0 * inverse;
return result;
}
}
/**
* @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
*/
function mulDiv(
uint256 x,
uint256 y,
uint256 denominator,
Rounding rounding
) internal pure returns (uint256) {
uint256 result = mulDiv(x, y, denominator);
if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
result += 1;
}
return result;
}
/**
* @dev Returns the square root of a number. It the number is not a perfect square, the value is rounded down.
*
* Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
*/
function sqrt(uint256 a) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
// For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
// We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
// `msb(a) <= a < 2*msb(a)`.
// We also know that `k`, the position of the most significant bit, is such that `msb(a) = 2**k`.
// This gives `2**k < a <= 2**(k+1)` → `2**(k/2) <= sqrt(a) < 2 ** (k/2+1)`.
// Using an algorithm similar to the msb conmputation, we are able to compute `result = 2**(k/2)` which is a
// good first aproximation of `sqrt(a)` with at least 1 correct bit.
uint256 result = 1;
uint256 x = a;
if (x >> 128 > 0) {
x >>= 128;
result <<= 64;
}
if (x >> 64 > 0) {
x >>= 64;
result <<= 32;
}
if (x >> 32 > 0) {
x >>= 32;
result <<= 16;
}
if (x >> 16 > 0) {
x >>= 16;
result <<= 8;
}
if (x >> 8 > 0) {
x >>= 8;
result <<= 4;
}
if (x >> 4 > 0) {
x >>= 4;
result <<= 2;
}
if (x >> 2 > 0) {
result <<= 1;
}
// At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
// since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
// every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
// into the expected uint128 result.
unchecked {
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
return min(result, a / result);
}
}
/**
* @notice Calculates sqrt(a), following the selected rounding direction.
*/
function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
uint256 result = sqrt(a);
if (rounding == Rounding.Up && result * result < a) {
result += 1;
}
return result;
}
}
// File: @openzeppelin/contracts/utils/cryptography/MerkleProof.sol
// OpenZeppelin Contracts (last updated v4.7.0) (utils/cryptography/MerkleProof.sol)
pragma solidity ^0.8.0;
/**
* @dev These functions deal with verification of Merkle Tree 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.
*
* WARNING: You should avoid using leaf values that are 64 bytes long prior to
* hashing, or use a hash function other than keccak256 for hashing leaves.
* This is because the concatenation of a sorted pair of internal nodes in
* the merkle tree could be reinterpreted as a leaf value.
*/
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) {
return processProof(proof, leaf) == root;
}
/**
* @dev Calldata version of {verify}
*
* _Available since v4.7._
*/
function verifyCalldata(
bytes32[] calldata proof,
bytes32 root,
bytes32 leaf
) internal pure returns (bool) {
return processProofCalldata(proof, leaf) == root;
}
/**
* @dev Returns the rebuilt hash obtained by traversing a Merkle tree up
* from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt
* hash matches the root of the tree. When processing the proof, the pairs
* of leafs & pre-images are assumed to be sorted.
*
* _Available since v4.4._
*/
function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
bytes32 computedHash = leaf;
for (uint256 i = 0; i < proof.length; i++) {
computedHash = _hashPair(computedHash, proof[i]);
}
return computedHash;
}
/**
* @dev Calldata version of {processProof}
*
* _Available since v4.7._
*/
function processProofCalldata(bytes32[] calldata proof, bytes32 leaf) internal pure returns (bytes32) {
bytes32 computedHash = leaf;
for (uint256 i = 0; i < proof.length; i++) {
computedHash = _hashPair(computedHash, proof[i]);
}
return computedHash;
}
/**
* @dev Returns true if the `leaves` can be proved to be a part of a Merkle tree defined by
* `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.
*
* _Available since v4.7._
*/
function multiProofVerify(
bytes32[] memory proof,
bool[] memory proofFlags,
bytes32 root,
bytes32[] memory leaves
) internal pure returns (bool) {
return processMultiProof(proof, proofFlags, leaves) == root;
}
/**
* @dev Calldata version of {multiProofVerify}
*
* _Available since v4.7._
*/
function multiProofVerifyCalldata(
bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32 root,
bytes32[] memory leaves
) internal pure returns (bool) {
return processMultiProofCalldata(proof, proofFlags, leaves) == root;
}
/**
* @dev Returns the root of a tree reconstructed from `leaves` and the sibling nodes in `proof`,
* consuming from one or the other at each step according to the instructions given by
* `proofFlags`.
*
* _Available since v4.7._
*/
function processMultiProof(
bytes32[] memory proof,
bool[] memory proofFlags,
bytes32[] memory leaves
) internal pure returns (bytes32 merkleRoot) {
// This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by
// consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
// `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
// the merkle tree.
uint256 leavesLen = leaves.length;
uint256 totalHashes = proofFlags.length;
// Check proof validity.
require(leavesLen + proof.length - 1 == totalHashes, "MerkleProof: invalid multiproof");
// The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
// `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
bytes32[] memory hashes = new bytes32[](totalHashes);
uint256 leafPos = 0;
uint256 hashPos = 0;
uint256 proofPos = 0;
// At each step, we compute the next hash using two values:
// - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
// get the next hash.
// - depending on the flag, either another value for the "main queue" (merging branches) or an element from the
// `proof` array.
for (uint256 i = 0; i < totalHashes; i++) {
bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
hashes[i] = _hashPair(a, b);
}
if (totalHashes > 0) {
return hashes[totalHashes - 1];
} else if (leavesLen > 0) {
return leaves[0];
} else {
return proof[0];
}
}
/**
* @dev Calldata version of {processMultiProof}
*
* _Available since v4.7._
*/
function processMultiProofCalldata(
bytes32[] calldata proof,
bool[] calldata proofFlags,
bytes32[] memory leaves
) internal pure returns (bytes32 merkleRoot) {
// This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by
// consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
// `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
// the merkle tree.
uint256 leavesLen = leaves.length;
uint256 totalHashes = proofFlags.length;
// Check proof validity.
require(leavesLen + proof.length - 1 == totalHashes, "MerkleProof: invalid multiproof");
// The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
// `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
bytes32[] memory hashes = new bytes32[](totalHashes);
uint256 leafPos = 0;
uint256 hashPos = 0;
uint256 proofPos = 0;
// At each step, we compute the next hash using two values:
// - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
// get the next hash.
// - depending on the flag, either another value for the "main queue" (merging branches) or an element from the
// `proof` array.
for (uint256 i = 0; i < totalHashes; i++) {
bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
hashes[i] = _hashPair(a, b);
}
if (totalHashes > 0) {
return hashes[totalHashes - 1];
} else if (leavesLen > 0) {
return leaves[0];
} else {
return proof[0];
}
}
function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {
return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
}
function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
/// @solidity memory-safe-assembly
assembly {
mstore(0x00, a)
mstore(0x20, b)
value := keccak256(0x00, 0x40)
}
}
}
// File: @openzeppelin/contracts/utils/Strings.sol
// OpenZeppelin Contracts v4.4.1 (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/security/ReentrancyGuard.sol
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)
pragma solidity ^0.8.0;
/**
* @dev Contract module that helps prevent reentrant calls to a function.
*
* Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
* available, which can be applied to functions to make sure there are no nested
* (reentrant) calls to them.
*
* Note that because there is a single `nonReentrant` guard, functions marked as
* `nonReentrant` may not call one another. This can be worked around by making
* those functions `private`, and then adding `external` `nonReentrant` entry
* points to them.
*
* TIP: If you would like to learn more about reentrancy and alternative ways
* to protect against it, check out our blog post
* https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
*/
abstract contract ReentrancyGuard {
// Booleans are more expensive than uint256 or any type that takes up a full
// word because each write operation emits an extra SLOAD to first read the
// slot's contents, replace the bits taken up by the boolean, and then write
// back. This is the compiler's defense against contract upgrades and
// pointer aliasing, and it cannot be disabled.
// The values being non-zero value makes deployment a bit more expensive,
// but in exchange the refund on every call to nonReentrant will be lower in
// amount. Since refunds are capped to a percentage of the total
// transaction's gas, it is best to keep them low in cases like this one, to
// increase the likelihood of the full refund coming into effect.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor() {
_status = _NOT_ENTERED;
}
/**
* @dev Prevents a contract from calling itself, directly or indirectly.
* Calling a `nonReentrant` function from another `nonReentrant`
* function is not supported. It is possible to prevent this from happening
* by making the `nonReentrant` function external, and making it call a
* `private` function that does the actual work.
*/
modifier nonReentrant() {
// On the first call to nonReentrant, _notEntered will be true
require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
// File: @openzeppelin/contracts/utils/Context.sol
// OpenZeppelin Contracts v4.4.1 (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: contracts/ERC721A.sol
// Creator: Chiru Labs
pragma solidity ^0.8.4;
error ApprovalCallerNotOwnerNorApproved();
error ApprovalQueryForNonexistentToken();
error ApproveToCaller();
error ApprovalToCurrentOwner();
error BalanceQueryForZeroAddress();
error MintToZeroAddress();
error MintZeroQuantity();
error OwnerQueryForNonexistentToken();
error TransferCallerNotOwnerNorApproved();
error TransferFromIncorrectOwner();
error TransferToNonERC721ReceiverImplementer();
error TransferToZeroAddress();
error URIQueryForNonexistentToken();
/**
* @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
* the Metadata extension. Built to optimize for lower gas during batch mints.
*
* Assumes serials are sequentially minted starting at _startTokenId() (defaults to 0, e.g. 0, 1, 2, 3..).
*
* Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.
*
* Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).
*/
contract ERC721A is Context, ERC165, IERC721, IERC721Metadata {
using Address for address;
using Strings for uint256;
// Compiler will pack this into a single 256bit word.
struct TokenOwnership {
// The address of the owner.
address addr;
// Keeps track of the start time of ownership with minimal overhead for tokenomics.
uint64 startTimestamp;
// Whether the token has been burned.
bool burned;
}
// Compiler will pack this into a single 256bit word.
struct AddressData {
// Realistically, 2**64-1 is more than enough.
uint64 balance;
// Keeps track of mint count with minimal overhead for tokenomics.
uint64 numberMinted;
// Keeps track of burn count with minimal overhead for tokenomics.
uint64 numberBurned;
// For miscellaneous variable(s) pertaining to the address
// (e.g. number of whitelist mint slots used).
// If there are multiple variables, please pack them into a uint64.
uint64 aux;
}
// The tokenId of the next token to be minted.
uint256 internal _currentIndex;
// The number of tokens burned.
uint256 internal _burnCounter;
// Token name
string private _name;
// Token symbol
string private _symbol;
// Mapping from token ID to ownership details
// An empty struct value does not necessarily mean the token is unowned. See _ownershipOf implementation for details.
mapping(uint256 => TokenOwnership) internal _ownerships;
// Mapping owner address to address data
mapping(address => AddressData) private _addressData;
// 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;
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
_currentIndex = _startTokenId();
}
/**
* To change the starting tokenId, please override this function.
*/
function _startTokenId() internal view virtual returns (uint256) {
return 0;
}
/**
* @dev Burned tokens are calculated here, use _totalMinted() if you want to count just minted tokens.
*/
function totalSupply() public view returns (uint256) {
// Counter underflow is impossible as _burnCounter cannot be incremented
// more than _currentIndex - _startTokenId() times
unchecked {
return _currentIndex - _burnCounter - _startTokenId();
}
}
/**
* Returns the total amount of tokens minted in the contract.
*/
function _totalMinted() internal view returns (uint256) {
// Counter underflow is impossible as _currentIndex does not decrement,
// and it is initialized to _startTokenId()
unchecked {
return _currentIndex - _startTokenId();
}
}
/**
* @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 override returns (uint256) {
if (owner == address(0)) revert BalanceQueryForZeroAddress();
return uint256(_addressData[owner].balance);
}
/**
* Returns the number of tokens minted by `owner`.
*/
function _numberMinted(address owner) internal view returns (uint256) {
return uint256(_addressData[owner].numberMinted);
}
/**
* Returns the number of tokens burned by or on behalf of `owner`.
*/
function _numberBurned(address owner) internal view returns (uint256) {
return uint256(_addressData[owner].numberBurned);
}
/**
* Returns the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
*/
function _getAux(address owner) internal view returns (uint64) {
return _addressData[owner].aux;
}
/**
* Sets the auxillary data for `owner`. (e.g. number of whitelist mint slots used).
* If there are multiple variables, please pack them into a uint64.
*/
function _setAux(address owner, uint64 aux) internal {
_addressData[owner].aux = aux;
}
/**
* Gas spent here starts off proportional to the maximum mint batch size.
* It gradually moves to O(1) as tokens get transferred around in the collection over time.
*/
function _ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
uint256 curr = tokenId;
unchecked {
if (_startTokenId() <= curr && curr < _currentIndex) {
TokenOwnership memory ownership = _ownerships[curr];
if (!ownership.burned) {
if (ownership.addr != address(0)) {
return ownership;
}
// Invariant:
// There will always be an ownership that has an address and is not burned
// before an ownership that does not have an address and is not burned.
// Hence, curr will not underflow.
while (true) {
curr--;
ownership = _ownerships[curr];
if (ownership.addr != address(0)) {
return ownership;
}
}
}
}
}
revert OwnerQueryForNonexistentToken();
}
/**
* @dev See {IERC721-ownerOf}.
*/
function ownerOf(uint256 tokenId) public view override returns (address) {
return _ownershipOf(tokenId).addr;
}
/**
* @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) {
if (!_exists(tokenId)) revert URIQueryForNonexistentToken();
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 override {
address owner = ERC721A.ownerOf(tokenId);
if (to == owner) revert ApprovalToCurrentOwner();
if (_msgSender() != owner && !isApprovedForAll(owner, _msgSender())) {
revert ApprovalCallerNotOwnerNorApproved();
}
_approve(to, tokenId, owner);
}
/**
* @dev See {IERC721-getApproved}.
*/
function getApproved(uint256 tokenId) public view override returns (address) {
if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();
return _tokenApprovals[tokenId];
}
/**
* @dev See {IERC721-setApprovalForAll}.
*/
function setApprovalForAll(address operator, bool approved) public virtual override {
if (operator == _msgSender()) revert ApproveToCaller();
_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 {
_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 {
_transfer(from, to, tokenId);
if (to.isContract() && !_checkContractOnERC721Received(from, to, tokenId, _data)) {
revert TransferToNonERC721ReceiverImplementer();
}
}
/**
* @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`),
*/
function _exists(uint256 tokenId) internal view returns (bool) {
return _startTokenId() <= tokenId && tokenId < _currentIndex && !_ownerships[tokenId].burned;
}
function _safeMint(address to, uint256 quantity) internal {
_safeMint(to, quantity, '');
}
/**
* @dev Safely mints `quantity` tokens and transfers them to `to`.
*
* Requirements:
*
* - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called for each safe transfer.
* - `quantity` must be greater than 0.
*
* Emits a {Transfer} event.
*/
function _safeMint(
address to,
uint256 quantity,
bytes memory _data
) internal {
_mint(to, quantity, _data, true);
}
/**
* @dev Mints `quantity` tokens and transfers them to `to`.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - `quantity` must be greater than 0.
*
* Emits a {Transfer} event.
*/
function _mint(
address to,
uint256 quantity,
bytes memory _data,
bool safe
) internal {
uint256 startTokenId = _currentIndex;
if (to == address(0)) revert MintToZeroAddress();
if (quantity == 0) revert MintZeroQuantity();
_beforeTokenTransfers(address(0), to, startTokenId, quantity);
// Overflows are incredibly unrealistic.
// balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
// updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
unchecked {
_addressData[to].balance += uint64(quantity);
_addressData[to].numberMinted += uint64(quantity);
_ownerships[startTokenId].addr = to;
_ownerships[startTokenId].startTimestamp = uint64(block.timestamp);
uint256 updatedIndex = startTokenId;
uint256 end = updatedIndex + quantity;
if (safe && to.isContract()) {
do {
emit Transfer(address(0), to, updatedIndex);
if (!_checkContractOnERC721Received(address(0), to, updatedIndex++, _data)) {
revert TransferToNonERC721ReceiverImplementer();
}
} while (updatedIndex != end);
// Reentrancy protection
if (_currentIndex != startTokenId) revert();
} else {
do {
emit Transfer(address(0), to, updatedIndex++);
} while (updatedIndex != end);
}
_currentIndex = updatedIndex;
}
_afterTokenTransfers(address(0), to, startTokenId, quantity);
}
/**
* @dev Transfers `tokenId` from `from` to `to`.
*
* 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
) private {
TokenOwnership memory prevOwnership = _ownershipOf(tokenId);
if (prevOwnership.addr != from) revert TransferFromIncorrectOwner();
bool isApprovedOrOwner = (_msgSender() == from ||
isApprovedForAll(from, _msgSender()) ||
getApproved(tokenId) == _msgSender());
if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
if (to == address(0)) revert TransferToZeroAddress();
_beforeTokenTransfers(from, to, tokenId, 1);
// Clear approvals from the previous owner
_approve(address(0), tokenId, from);
// Underflow of the sender's balance is impossible because we check for
// ownership above and the recipient's balance can't realistically overflow.
// Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
unchecked {
_addressData[from].balance -= 1;
_addressData[to].balance += 1;
TokenOwnership storage currSlot = _ownerships[tokenId];
currSlot.addr = to;
currSlot.startTimestamp = uint64(block.timestamp);
// If the ownership slot of tokenId+1 is not explicitly set, that means the transfer initiator owns it.
// Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
uint256 nextTokenId = tokenId + 1;
TokenOwnership storage nextSlot = _ownerships[nextTokenId];
if (nextSlot.addr == address(0)) {
// This will suffice for checking _exists(nextTokenId),
// as a burned slot cannot contain the zero address.
if (nextTokenId != _currentIndex) {
nextSlot.addr = from;
nextSlot.startTimestamp = prevOwnership.startTimestamp;
}
}
}
emit Transfer(from, to, tokenId);
_afterTokenTransfers(from, to, tokenId, 1);
}
/**
* @dev This is equivalent to _burn(tokenId, false)
*/
function _burn(uint256 tokenId) internal virtual {
_burn(tokenId, false);
}
/**
* @dev Destroys `tokenId`.
* The approval is cleared when the token is burned.
*
* Requirements:
*
* - `tokenId` must exist.
*
* Emits a {Transfer} event.
*/
function _burn(uint256 tokenId, bool approvalCheck) internal virtual {
TokenOwnership memory prevOwnership = _ownershipOf(tokenId);
address from = prevOwnership.addr;
if (approvalCheck) {
bool isApprovedOrOwner = (_msgSender() == from ||
isApprovedForAll(from, _msgSender()) ||
getApproved(tokenId) == _msgSender());
if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
}
_beforeTokenTransfers(from, address(0), tokenId, 1);
// Clear approvals from the previous owner
_approve(address(0), tokenId, from);
// Underflow of the sender's balance is impossible because we check for
// ownership above and the recipient's balance can't realistically overflow.
// Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
unchecked {
AddressData storage addressData = _addressData[from];
addressData.balance -= 1;
addressData.numberBurned += 1;
// Keep track of who burned the token, and the timestamp of burning.
TokenOwnership storage currSlot = _ownerships[tokenId];
currSlot.addr = from;
currSlot.startTimestamp = uint64(block.timestamp);
currSlot.burned = true;
// If the ownership slot of tokenId+1 is not explicitly set, that means the burn initiator owns it.
// Set the slot of tokenId+1 explicitly in storage to maintain correctness for ownerOf(tokenId+1) calls.
uint256 nextTokenId = tokenId + 1;
TokenOwnership storage nextSlot = _ownerships[nextTokenId];
if (nextSlot.addr == address(0)) {
// This will suffice for checking _exists(nextTokenId),
// as a burned slot cannot contain the zero address.
if (nextTokenId != _currentIndex) {
nextSlot.addr = from;
nextSlot.startTimestamp = prevOwnership.startTimestamp;
}
}
}
emit Transfer(from, address(0), tokenId);
_afterTokenTransfers(from, address(0), tokenId, 1);
// Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
unchecked {
_burnCounter++;
}
}
/**
* @dev Approve `to` to operate on `tokenId`
*
* Emits a {Approval} event.
*/
function _approve(
address to,
uint256 tokenId,
address owner
) private {
_tokenApprovals[tokenId] = to;
emit Approval(owner, to, tokenId);
}
/**
* @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target 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 _checkContractOnERC721Received(
address from,
address to,
uint256 tokenId,
bytes memory _data
) private returns (bool) {
try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, _data) returns (bytes4 retval) {
return retval == IERC721Receiver(to).onERC721Received.selector;
} catch (bytes memory reason) {
if (reason.length == 0) {
revert TransferToNonERC721ReceiverImplementer();
} else {
assembly {
revert(add(32, reason), mload(reason))
}
}
}
}
/**
* @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.
* And also called before burning one token.
*
* startTokenId - the first token id to be transferred
* quantity - the amount to be transferred
*
* 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, `tokenId` will be burned by `from`.
* - `from` and `to` are never both zero.
*/
function _beforeTokenTransfers(
address from,
address to,
uint256 startTokenId,
uint256 quantity
) internal virtual {}
/**
* @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes
* minting.
* And also called after one token has been burned.
*
* startTokenId - the first token id to be transferred
* quantity - the amount to be transferred
*
* Calling conditions:
*
* - When `from` and `to` are both non-zero, `from`'s `tokenId` has been
* transferred to `to`.
* - When `from` is zero, `tokenId` has been minted for `to`.
* - When `to` is zero, `tokenId` has been burned by `from`.
* - `from` and `to` are never both zero.
*/
function _afterTokenTransfers(
address from,
address to,
uint256 startTokenId,
uint256 quantity
) internal virtual {}
}
// File: @openzeppelin/contracts/access/Ownable.sol
// OpenZeppelin Contracts v4.4.1 (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() {
_transferOwnership(_msgSender());
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
_transferOwnership(address(0));
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Internal function without access restriction.
*/
function _transferOwnership(address newOwner) internal virtual {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
pragma solidity ^0.8.13;
contract BearRiders is ERC721A, Ownable, ReentrancyGuard {
using Strings for uint256;
enum MintState {
// PUBLIC: open for all, integer id: 0
PUBLIC,
// WHITELIST: only used for
WHITELIST,
// mint is closed, only admin/owner may mint
CLOSED
}
uint256 public constant MINT_PER_ACCOUNT = 3;
uint256 public immutable MAX_SUPPLY;
// the state of whether minting is allowed.
MintState private mintingState = MintState.CLOSED;
string public readMeURI;
// the base uri for the token
string public baseURI;
string public unrevealedURI;
constructor(
uint256 maxSupply,
string memory name, string memory symbol
) ERC721A(name, symbol) {
MAX_SUPPLY = maxSupply;
}
/**
* To change the starting tokenId, please override this function.
*/
function _startTokenId() internal override view virtual returns (uint256) {
return 1;
}
function setReadMeURI(string calldata _uri) external onlyOwner {
readMeURI = _uri;
}
function setBaseURI(string calldata _uri) external onlyOwner {
baseURI = _uri;
}
function setUnrevealedURI(string calldata _uri) external onlyOwner {
unrevealedURI = _uri;
}
function tokenURI(uint256 tokenId)
public
view
override
returns (string memory)
{
require(
_exists(tokenId),
"ERC721Metadata: URI query for nonexistent token"
);
return bytes(baseURI).length > 0
? string(
abi.encodePacked(
baseURI,
tokenId.toString(),
".json"))
: unrevealedURI;
}
modifier mintOpen() {
require(mintingState == MintState.PUBLIC, "minting not active.");
_;
}
function ownerMint(uint16 amount) external onlyOwner {
uint256 totalSupply = totalSupply();
// ensure minting the amount entered would not mint over the max supply
require(
totalSupply + amount < MAX_SUPPLY,
"mint amount would be out of range."
);
_safeMint(_msgSender(), amount);
}
function max(int256 a, int256 b) internal pure returns(int256) {
return a > b ? a : b;
}
function min(int256 a, int256 b) internal pure returns(int256) {
return a < b ? a : b;
}
function mint(uint256 amount) external nonReentrant mintOpen {
require(_totalMinted() < MAX_SUPPLY, "minted out.");
require(_totalMinted() + amount <= MAX_SUPPLY, "mint amount would be out of range.");
require(msg.sender == tx.origin);
require(amount > 0 && amount <= MINT_PER_ACCOUNT, "number too large");
uint minted = _numberMinted(msg.sender);
require(minted < 3, "max amount minted");
// this will determine how many free mints are left.
// 1000 - 999 = 1
// for example
// int256 remainingFreeMints = max(int256(MAX_FREE_MINTS) - int256(totalSupply()), 0);
// uint256 requiredPrice = 0;
// if (remainingFreeMints > 0) {
// // we have free mint left.
// // limit the user to 1 per free mint.
// require(amount == 1, "you may only mint one free NFT at this time.");
// require(minted < 1, "account already claimed free mint");
// // mark their account as having minted during free mint
// _setAux(msg.sender, 1);
// } else {
// uint256 accountMintLimit = MINT_PER_ACCOUNT;
// if (_getAux(msg.sender) > 0) {
// // being greater than 1, means they minted during the free period. allow them to mint an extra one during paid.
// accountMintLimit += 1;
// }
// require(minted < accountMintLimit, "mint limit reached");
// require(minted + amount <= accountMintLimit, "mint limit reached");
// requiredPrice = amount * MINT_PRICE;
// }
// if (requiredPrice > 0) {
// require(msg.value >= requiredPrice, "out of free mints, must pay 0.005 ether for each");
// }
_safeMint(msg.sender, amount);
// if (msg.value > requiredPrice) {
// uint256 diff = msg.value - requiredPrice;
// (bool ok,) = payable(msg.sender).call{value: diff}("");
// require(ok, "failed to send refund.");
// }
}
// toggles the state of mint
function setMintingState(MintState state) external onlyOwner {
mintingState = state;
}
// Issue a withdrawal to a specific address
function withdraw(address sendTo) external onlyOwner {
(bool ok, ) = payable(sendTo).call{value: address(this).balance}("");
require(ok);
}
}