Contract Source Code:
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @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 Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
_checkOwner();
_;
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
/**
* @dev Throws if the sender is not the owner.
*/
function _checkOwner() internal view virtual {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby disabling 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);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: Beware that changing an allowance with this method brings the risk
* that someone may use both the old and the new allowance by unfortunate
* transaction ordering. One possible solution to mitigate this race
* condition is to first reduce the spender's allowance to 0 and set the
* desired value afterwards:
* https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `from` to `to` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address from, address to, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.4) (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;
}
function _contextSuffixLength() internal view virtual returns (uint256) {
return 0;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/cryptography/ECDSA.sol)
pragma solidity ^0.8.0;
import "../Strings.sol";
/**
* @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 // Deprecated in v4.8
}
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");
}
}
/**
* @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) {
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.
/// @solidity memory-safe-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 {
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 = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
uint8 v = uint8((uint256(vs) >> 255) + 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 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 message) {
// 32 is the length in bytes of hash,
// enforced by the type signature above
/// @solidity memory-safe-assembly
assembly {
mstore(0x00, "\x19Ethereum Signed Message:\n32")
mstore(0x1c, hash)
message := keccak256(0x00, 0x3c)
}
}
/**
* @dev Returns an Ethereum Signed Message, created from `s`. 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(bytes memory s) internal pure returns (bytes32) {
return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", Strings.toString(s.length), s));
}
/**
* @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 data) {
/// @solidity memory-safe-assembly
assembly {
let ptr := mload(0x40)
mstore(ptr, "\x19\x01")
mstore(add(ptr, 0x02), domainSeparator)
mstore(add(ptr, 0x22), structHash)
data := keccak256(ptr, 0x42)
}
}
/**
* @dev Returns an Ethereum Signed Data with intended validator, created from a
* `validator` and `data` according to the version 0 of EIP-191.
*
* See {recover}.
*/
function toDataWithIntendedValidatorHash(address validator, bytes memory data) internal pure returns (bytes32) {
return keccak256(abi.encodePacked("\x19\x00", validator, data));
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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) {
// Solidity will revert if denominator == 0, unlike the div opcode on its own.
// The surrounding unchecked block does not change this fact.
// See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
return prod0 / denominator;
}
// Make sure the result is less than 2^256. Also prevents denominator == 0.
require(denominator > prod1, "Math: mulDiv overflow");
///////////////////////////////////////////////
// 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. If 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)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
//
// This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
// → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
// → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
//
// Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
uint256 result = 1 << (log2(a) >> 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) {
unchecked {
uint256 result = sqrt(a);
return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
}
}
/**
* @dev Return the log in base 2, rounded down, of a positive value.
* Returns 0 if given 0.
*/
function log2(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >> 128 > 0) {
value >>= 128;
result += 128;
}
if (value >> 64 > 0) {
value >>= 64;
result += 64;
}
if (value >> 32 > 0) {
value >>= 32;
result += 32;
}
if (value >> 16 > 0) {
value >>= 16;
result += 16;
}
if (value >> 8 > 0) {
value >>= 8;
result += 8;
}
if (value >> 4 > 0) {
value >>= 4;
result += 4;
}
if (value >> 2 > 0) {
value >>= 2;
result += 2;
}
if (value >> 1 > 0) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 2, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log2(value);
return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
}
}
/**
* @dev Return the log in base 10, rounded down, of a positive value.
* Returns 0 if given 0.
*/
function log10(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >= 10 ** 64) {
value /= 10 ** 64;
result += 64;
}
if (value >= 10 ** 32) {
value /= 10 ** 32;
result += 32;
}
if (value >= 10 ** 16) {
value /= 10 ** 16;
result += 16;
}
if (value >= 10 ** 8) {
value /= 10 ** 8;
result += 8;
}
if (value >= 10 ** 4) {
value /= 10 ** 4;
result += 4;
}
if (value >= 10 ** 2) {
value /= 10 ** 2;
result += 2;
}
if (value >= 10 ** 1) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 10, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log10(value);
return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
}
}
/**
* @dev Return the log in base 256, rounded down, of a positive value.
* Returns 0 if given 0.
*
* Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
*/
function log256(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >> 128 > 0) {
value >>= 128;
result += 16;
}
if (value >> 64 > 0) {
value >>= 64;
result += 8;
}
if (value >> 32 > 0) {
value >>= 32;
result += 4;
}
if (value >> 16 > 0) {
value >>= 16;
result += 2;
}
if (value >> 8 > 0) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 256, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log256(value);
return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SignedMath.sol)
pragma solidity ^0.8.0;
/**
* @dev Standard signed math utilities missing in the Solidity language.
*/
library SignedMath {
/**
* @dev Returns the largest of two signed numbers.
*/
function max(int256 a, int256 b) internal pure returns (int256) {
return a > b ? a : b;
}
/**
* @dev Returns the smallest of two signed numbers.
*/
function min(int256 a, int256 b) internal pure returns (int256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two signed numbers without overflow.
* The result is rounded towards zero.
*/
function average(int256 a, int256 b) internal pure returns (int256) {
// Formula from the book "Hacker's Delight"
int256 x = (a & b) + ((a ^ b) >> 1);
return x + (int256(uint256(x) >> 255) & (a ^ b));
}
/**
* @dev Returns the absolute unsigned value of a signed value.
*/
function abs(int256 n) internal pure returns (uint256) {
unchecked {
// must be unchecked in order to support `n = type(int256).min`
return uint256(n >= 0 ? n : -n);
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Strings.sol)
pragma solidity ^0.8.0;
import "./math/Math.sol";
import "./math/SignedMath.sol";
/**
* @dev String operations.
*/
library Strings {
bytes16 private constant _SYMBOLS = "0123456789abcdef";
uint8 private constant _ADDRESS_LENGTH = 20;
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/
function toString(uint256 value) internal pure returns (string memory) {
unchecked {
uint256 length = Math.log10(value) + 1;
string memory buffer = new string(length);
uint256 ptr;
/// @solidity memory-safe-assembly
assembly {
ptr := add(buffer, add(32, length))
}
while (true) {
ptr--;
/// @solidity memory-safe-assembly
assembly {
mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
}
value /= 10;
if (value == 0) break;
}
return buffer;
}
}
/**
* @dev Converts a `int256` to its ASCII `string` decimal representation.
*/
function toString(int256 value) internal pure returns (string memory) {
return string(abi.encodePacked(value < 0 ? "-" : "", toString(SignedMath.abs(value))));
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
*/
function toHexString(uint256 value) internal pure returns (string memory) {
unchecked {
return toHexString(value, Math.log256(value) + 1);
}
}
/**
* @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] = _SYMBOLS[value & 0xf];
value >>= 4;
}
require(value == 0, "Strings: hex length insufficient");
return string(buffer);
}
/**
* @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
*/
function toHexString(address addr) internal pure returns (string memory) {
return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
}
/**
* @dev Returns true if the two strings are equal.
*/
function equal(string memory a, string memory b) internal pure returns (bool) {
return keccak256(bytes(a)) == keccak256(bytes(b));
}
}
// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.8.19;
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
import { TransferHelper } from "./libraries/TransferHelper.sol";
contract DiceGame is Ownable {
using TransferHelper for address;
struct GameRound {
bool fulfilled; // whether the request has been successfully fulfilled
address user;
uint256 totalBet;
uint256 totalWinnings;
uint256[] betAmts;
uint256[] diceRollResult;
}
uint256 public constant WIN69_MULTIPLIER = 10;
uint256 public constant CALLBACK_GAS = 200_000;
uint256 public constant MAX_OPERATOR_GAS = 1_000_000;
uint256 public constant MAX_NUM_WORDS = 3;
uint256 public constant DELIMITER = 1e18;
uint8 public constant decimals = 18;
string public constant name = "Banana Points";
string public constant symbol = "BPT";
uint256 public rollOperatorGas = 600_000;
uint256 public immutable gamePeriod;
address public coin;
address public immutable V3Deployer;
address public wrappedNative;
address public immutable gameRngWallet;
address public immutable rollOperator;
/// @notice Timestamp when the geme ower
uint256 public endTime;
/// @notice Initial rate of tokens per coin
uint256 public initialTokenRate;
uint256 public gameId;
uint256 public lastFulfilledGameId;
// The total supply of points in existence
uint256 public totalSupply;
// Maps an address to their current balance
mapping(address => uint256) private userBalances;
// Maps a game ID to its round information
mapping(uint256 => GameRound) private gameRounds; /* gameId --> GameRound */
// Maps an address to their game IDs
mapping(address => uint256[]) public userGameIds;
constructor(
address _gameRngWalletAddress,
uint _gamePeriod,
address _V3Deployer,
address _rollOperator
) {
gameRngWallet = _gameRngWalletAddress;
if (_gameRngWalletAddress == address(0) || _V3Deployer == address(0)) revert ZeroValue();
if (_gamePeriod < 2 hours || _gamePeriod > 180 days) revert GamePeriod();
gamePeriod = _gamePeriod;
rollOperator = _rollOperator;
V3Deployer = _V3Deployer;
transferOwnership(_V3Deployer);
}
event MintPoints(address recipient, uint256 pointsAmount);
event BurnPoints(address from, uint256 pointsAmount);
event Redeem(address user, uint256 amount);
event PurchasePoints(address user, uint256 paymentAmount);
event Bet(uint256 gameId, address user, uint256 totalBetAmt);
event BetFailed(address user);
error AmountOfEthSentIsTooSmall(uint256 sent, uint256 minimum);
error InvalidGameId(uint256 id);
error InvalidLength();
error InvaliddiceRollResult(uint256 id);
error GamePeriod();
error ZeroValue();
error NotEnoughCoinBalance(uint256 want, uint256 have);
error Forbidden();
// Modifiers
modifier shouldGameIsNotOver() {
require(gameNotOver(), "game over");
_;
}
modifier shouldGameIsOver() {
require(gameOver(), "game is NOT over");
_;
}
/// @notice Receive ETH and forward to `sponsorWallet`.
receive() external payable {
(bool success, ) = gameRngWallet.call{ value: msg.value }("");
require(success);
}
/**
* @notice Starts a new game with specific parameters Airnode details, initial token rate, etc.
* non-zero initial token rate, and game not already started (initialTokenRate == 0).
* @param _initialTokenRate The initial rate used within the game logic, set at the start and never changed afterward.
* @param _coin address of Coin token for this Game
* @custom:modifier onlyOwner Restricts the function's execution to the contract's owner.
*/
function startGame(
uint _initialTokenRate,
address _coin,
address _wrappedNative
) external payable onlyOwner {
// Ensure the initial token rate is not already set
require(initialTokenRate == 0, "o-o");
if (_coin == address(0)) revert ZeroValue();
// Initialize the initial token rate and calculate the end time based on the current timestamp
initialTokenRate = _initialTokenRate;
coin = _coin;
wrappedNative = _wrappedNative;
endTime = block.timestamp + gamePeriod;
if (msg.value > 0) {
(bool success, ) = gameRngWallet.call{ value: msg.value }("");
require(success);
}
}
/// @notice Retrieves the balance of a given account
/// @dev Returns the current balance stored in `userBalances`
/// @param account The address of the user whose balance we want to retrieve
/// @return The balance of the user
function balanceOf(address account) public view returns (uint256) {
return userBalances[account];
}
/// @notice Retrieves info of particular game id
/// @param _gameId game number/id
/// @return gameInfo GameRound struct
function getGameRoundInfo(uint256 _gameId) public view returns (GameRound memory gameInfo) {
gameInfo = gameRounds[_gameId];
}
/// @notice Retrieves the list of game IDs associated with a given user
/// @dev Fetches the array of game IDs from `userGameIds` using `.values()`
/// @param user The address of the user whose game IDs we want to retrieve
/// @return ids An array of game IDs that the user participated in
function getUserGameIds(address user) public view returns (uint256[] memory ids) {
ids = userGameIds[user];
}
/// @notice Retrieves the number of games a user has participated in
/// @dev Calculates the length of the user's game IDs set
/// @param user The address of the user whose number of games we want to know
/// @return num The number of games the user has participated in
function getUserGamesNumber(address user) public view returns (uint256 num) {
num = userGameIds[user].length;
}
// @notice Retrieves the last game information for a given user
/// @dev Fetches the last game ID and corresponding round info from `userGameIds` and `gameRounds`
/// @param user The address of the user whose last game information we want to retrieve
/// @return id The ID of the last game the user participated in
/// @return round The GameRound struct containing the details of the game round
function getUserLastGameInfo(
address user
) public view returns (uint256 id, GameRound memory round) {
uint256 length = userGameIds[user].length;
if (length > 0) {
id = userGameIds[user][length - 1];
round = gameRounds[id];
}
}
/// @notice Determines whether the game is still ongoing or not
/// @dev Compares the current block timestamp against `endTime`; also ensures that the game has started by requiring `_endTime` to be non-zero
/// @return Whether the current time is before the game's end time (`true`) or after (`false`)
function gameNotOver() public view returns (bool) {
uint256 _endTime = endTime;
_checkZero(_endTime);
return block.timestamp < _endTime;
}
/**
* @notice Checks if the game has been concluded based on the time limit.
* @dev Returns true if the current block timestamp exceeds the end time of the game by 10 minutes.
* This implies a grace period of 10 minutes after the official end time before declaring the game over.
* The function requires that `endTime` is set and the game has started, otherwise it reverts with an error message.
*
* @return A boolean value indicating whether the game is over (true) or not (false).
*/
function gameOver() public view returns (bool) {
uint256 _endTime = endTime;
_checkZero(_endTime);
return (block.timestamp > _endTime && gameId == lastFulfilledGameId);
}
struct GameState {
uint256 gameId;
uint256 betNumber;
}
/// @dev This function returns the state of games that have not yet been fulfilled.
/// It constructs an array of `GameState` structures representing each unfulfilled game's
/// ID and the count of bets placed in that game round.
/// The function only includes games with IDs greater than `lastFulfilledGameId`.
/// @return state An array of `GameState` structs for each unfulfilled game.
function getGameState() public view returns (GameState[] memory state) {
if (gameId > lastFulfilledGameId) {
uint256 requests = gameId - lastFulfilledGameId;
state = new GameState[](requests);
uint256 index;
while (lastFulfilledGameId + index < gameId) {
uint256 id = lastFulfilledGameId + index + 1;
state[index].gameId = id;
state[index].betNumber = gameRounds[id].betAmts.length;
index++;
}
}
}
/// @notice Allows a user to place a bet on a dice roll(s), record the bet details, and request randomness
/// @dev Transfers the required ETH to sponsor wallet and creates a new game round with provided bets
/// @param _betAmts An array of amounts representing individual bets for each roll of the dice
function bet(uint256[] memory _betAmts) external payable shouldGameIsNotOver {
// user must send enough native for the callback
// otherwise the transaction will fail
uint256 minimumSend = tx.gasprice * CALLBACK_GAS;
_checkAmount(minimumSend);
// Transfer the received native to the gameRngWallet wallet to cover the callback transaction costs
(bool success, ) = gameRngWallet.call{ value: msg.value }("");
require(success);
_bet(msg.sender, _betAmts);
}
struct OperatorInput {
address user;
uint256[] betAmts;
}
/// @notice Allows roll operator to place batch bets for different users. Operator must add users to batch who
/// have enough wrapped native tokens, have given approval for it, and have fulfilled their last game round
/// @param _inputs encoded input for array of OperatorInput structs
function bet(bytes calldata _inputs) external payable shouldGameIsNotOver {
if (msg.sender != rollOperator) revert();
OperatorInput[] memory batchInfo = abi.decode(_inputs, (OperatorInput[]));
uint length = batchInfo.length;
if (length == 0 || length > 30) revert InvalidLength();
uint256 minimumSend = tx.gasprice * CALLBACK_GAS * length;
uint256 gasAmt = tx.gasprice * rollOperatorGas;
_checkAmount(minimumSend);
OperatorInput memory info;
uint successCount;
for (uint i; i < length; ) {
info = batchInfo[i];
try this.processBatchBet(info.user, info.betAmts) {
unchecked {
++successCount;
}
} catch {
emit BetFailed(info.user);
}
unchecked {
++i;
}
}
uint refund;
if (successCount > 0) {
uint gasRandomizer = (msg.value * successCount) / length;
refund = msg.value - gasRandomizer;
(bool success, ) = gameRngWallet.call{ value: gasRandomizer }("");
require(success);
(bool result, ) = wrappedNative.call(
abi.encodeWithSignature(
"withdrawTo(address,uint256)",
msg.sender,
gasAmt * successCount
)
);
require(result, "withdrawTo");
} else {
refund = msg.value;
}
if (refund > 0) {
(bool success, ) = msg.sender.call{ value: refund }("");
require(success);
}
}
function processBatchBet(address _user, uint[] memory _betAmts) external shouldGameIsNotOver {
if (tx.origin != rollOperator) revert();
uint gasAmt;
unchecked {
gasAmt = tx.gasprice * rollOperatorGas;
}
wrappedNative.safeTransferFrom(_user, address(this), gasAmt);
_bet(_user, _betAmts);
}
/// @notice Allows roll operator place bets for users
/// @param _user Address of certain user
/// @param _betAmts An array of amounts representing individual bets for each roll of the dice
function bet(address _user, uint256[] memory _betAmts) external payable shouldGameIsNotOver {
if (msg.sender != rollOperator) revert();
// msg.value must be enough to cover randomizer gas spends
uint256 minimumSend = tx.gasprice * CALLBACK_GAS;
// take from user gas amount*gas.price
uint256 gasAmt = tx.gasprice * rollOperatorGas;
_checkAmount(minimumSend);
wrappedNative.safeTransferFrom(_user, address(this), gasAmt);
(bool success, ) = wrappedNative.call(
abi.encodeWithSignature("withdrawTo(address,uint256)", msg.sender, gasAmt)
);
require(success, "withdrawTo");
// send to randomizer 200_000gas*gas.price for callback
(bool result, ) = gameRngWallet.call{ value: msg.value }("");
require(result);
_bet(_user, _betAmts);
}
function _bet(address _user, uint256[] memory betAmts) internal {
(uint256 id, GameRound memory round) = getUserLastGameInfo(_user);
require(round.fulfilled || id == 0, "last round not fulfilled");
// Check if the number of dice rolls is within the permitted range
uint256 numWords = betAmts.length;
require(numWords > 0 && numWords <= MAX_NUM_WORDS, "invalid betAmts");
// Calculate the total bet amount from the array of bets
uint256 totalBetAmt;
for (uint i; i < numWords; ) {
// Each bet amount must be greater than zero
_checkZero(betAmts[i]);
unchecked {
totalBetAmt += betAmts[i];
++i;
}
}
// Ensure the user has enough points to cover their total bet
// It is possible to resend a bid for the same balance,
// so this check is also added to the callback function
require(totalBetAmt <= balanceOf(_user), "points are not enough");
_burnPoints(_user, totalBetAmt);
unchecked {
++gameId;
}
uint256 _gameId = gameId;
// Record the game round details in the contract state
gameRounds[_gameId] = GameRound({
fulfilled: false,
user: _user,
totalBet: totalBetAmt,
totalWinnings: 0,
betAmts: betAmts,
diceRollResult: new uint256[](betAmts.length)
});
// Associate the game ID with the user's address
userGameIds[_user].push(_gameId);
emit Bet(_gameId, _user, totalBetAmt);
}
struct RandomData {
uint256 id;
uint256[] rn;
}
/**
* @notice Fulfills the generation of random words if gas requirement is met
* @dev Processes each `RandomData` entries until either all are processed or minimum remaining gas is not met
* @param minRemainingGas The minimum amount of gas that must be left for the function to continue processing
* @param randomData An array of `RandomData` structs containing the IDs and random number arrays to process
* Requirements:
* - Only callable by the `gameRngWallet`.
* - Will stop processing if the remaining gas is less than `minRemainingGas`.
* Emits a `RandomWordsFulfilled` event upon successful processing of an entry.
* Uses the `_fulfillRandomWords` internal function to process each entry.
*/
function fulfillRandomWords(uint256 minRemainingGas, RandomData[] memory randomData) external {
require(msg.sender == gameRngWallet, "invalid caller");
for (uint256 i; i < randomData.length; ) {
if (gasleft() < minRemainingGas) {
break;
}
_fulfillRandomWords(randomData[i].id, randomData[i].rn);
unchecked {
++i;
}
}
}
/// @notice Records the result of dice rolls, updates the game round, and handles payouts
/// @dev Requires the caller to be the designated AirnodeRrp address and checks if the round can be fulfilled
/// @param _gameId The unique identifier of the game round that the dice roll results correspond to
/// @param _randomWords The array of random numbers provided by off-chain QRNG service
/// Using the QRNG service is free, meaning there is no subscription fee to pay.
/// There is a gas cost incurred on-chain when Airnode places the random number on-chain in response to a request,
/// which the requester needs to pay for.
function _fulfillRandomWords(uint256 _gameId, uint256[] memory _randomWords) private {
unchecked {
++lastFulfilledGameId;
}
// Retrieve the game round using the _gameId
GameRound storage round = gameRounds[_gameId];
uint256 totalBet = round.totalBet;
if (_gameId != lastFulfilledGameId || totalBet == 0) {
revert InvalidGameId(_gameId);
}
uint256 length = _randomWords.length;
if (length != round.diceRollResult.length) {
revert InvaliddiceRollResult(_gameId);
}
// Mark the round as fulfilled
round.fulfilled = true;
uint256 totalWinnings;
uint256 bitDice;
bool double3;
for (uint i; i < length; ) {
// Get the dice number between 1 and 6
uint256 num = (_randomWords[i] % 6) + 1;
// Calculate winnings based on even dice numbers
if (num % 2 == 0) {
totalWinnings += round.betAmts[i] * 2;
}
// Special logic for determining 33
if (num == 3 && !double3 && bitDice & (1 << num) == (1 << num)) {
double3 = true;
}
bitDice |= (1 << num);
round.diceRollResult[i] = num;
unchecked {
++i;
}
}
// Special logic for determining winnings if the special 69 condition is met
// or if the special 666 condition is met
// or if the special repdigit condition is met
if (length == 3) {
//Repdigit
if ((bitDice & (bitDice - 1)) == 0) {
totalWinnings = 0;
if (bitDice == 64) {
// 666
uint256 balance = balanceOf(round.user);
if (balance > 0) {
_burnPoints(round.user, balance);
}
}
} else if ((bitDice == 72 && !double3) || bitDice == 112) {
// 69
totalWinnings = totalBet * WIN69_MULTIPLIER;
}
}
if (totalWinnings > 0) {
round.totalWinnings = totalWinnings;
_mintPoints(round.user, totalWinnings);
}
}
/**
* @notice Allows users to purchase a specified amount of points.
* @param desiredAmountOut The exact amount of points the user wants to purchase.
*/
function purchasePoints(uint256 desiredAmountOut) external shouldGameIsNotOver {
uint256 paymentAmount = calculatePaymentAmount(desiredAmountOut);
coin.safeTransferFrom(msg.sender, address(this), paymentAmount);
_checkZero(desiredAmountOut);
_mintPoints(msg.sender, desiredAmountOut);
emit PurchasePoints(msg.sender, paymentAmount);
}
/**
* @notice Calculates the payment amount required for purchasing a specific amount of points.
* @param desiredPointsAmount The desired amount of points.
* @return paymentAmount The corresponding amount of payment currency that can be purchased/sold for the specified points.
*/
function calculatePaymentAmount(
uint256 desiredPointsAmount
) public view returns (uint256 paymentAmount) {
uint256 tokenRate = initialTokenRate;
if (tokenRate == 0) revert ZeroValue();
uint256 intermediate = desiredPointsAmount * DELIMITER;
paymentAmount = intermediate / tokenRate;
// Round up only for buying
if (paymentAmount == 0 || intermediate % tokenRate > 0) {
paymentAmount += 1;
}
}
/**
* @notice Calculates the points amount a user receives for a given coin amount.
* @param paymentAmount Amount of the payment currency (e.g., ETH) used to purchase tokens.
* @return pointsAmount The resulting amount of tokens that can be purchased for the specified `paymentAmount`.
*/
function calculatePointsAmount(
uint256 paymentAmount
) public view returns (uint256 pointsAmount) {
uint256 rate = initialTokenRate;
if (rate == 0) revert ZeroValue();
pointsAmount = (paymentAmount * rate) / DELIMITER;
}
function sendLiquidity() external shouldGameIsOver onlyOwner returns (uint amount) {
amount = coin.getBalance();
coin.safeTransfer(V3Deployer, amount);
}
function setOperatorGas(uint256 _operatorGas) external onlyOwner {
_checkZero(_operatorGas);
if (_operatorGas > MAX_OPERATOR_GAS) revert();
rollOperatorGas = _operatorGas;
}
/// @notice Redeem points for tokens.
/// @dev Burns points from the redeemer's balance and mints equivalent tokens.
/// Emits a Redeem event upon success.
/// Requires the game to be over.
/// Requires the Token to have been set and the caller to have a non-zero point balance.
/// @param signature 65 bytes signature for verify eligibility redeem tokens
function redeem(bytes calldata signature) external shouldGameIsOver {
bytes32 message = withPrefix(
keccak256(abi.encodePacked(msg.sender, block.chainid, address(this)))
);
require(ECDSA.recover(message, signature) == rollOperator, "invalid signature!");
uint256 amount = balanceOf(msg.sender);
_checkZero(amount);
_burnPoints(msg.sender, amount);
(bool success, ) = V3Deployer.call(
abi.encodeWithSignature("redeem(address,uint256)", msg.sender, amount)
);
require(success);
emit Redeem(msg.sender, amount);
}
function withPrefix(bytes32 _hash) private pure returns (bytes32) {
return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", _hash));
}
/// @notice Mints points and assigns them to a specified account
/// @dev Increments `userBalances` and `totalSupply` by the given `amount`
/// @param to The address of the recipient to whom points are to be minted
/// @param amount The quantity of points to be minted
function _mintPoints(address to, uint256 amount) private {
userBalances[to] += amount;
totalSupply += amount;
emit MintPoints(to, amount);
}
/// @notice Burns points from a specified account's balance
/// @dev Decrements `userBalances` and `totalSupply` by the given `amount`
/// @param from The address from which points are to be burned
/// @param amount The quantity of points to be burned
function _burnPoints(address from, uint256 amount) private {
userBalances[from] -= amount;
totalSupply -= amount;
emit BurnPoints(from, amount);
}
function _checkZero(uint256 amount) private pure {
require(amount > 0, "is zero");
}
function _checkAmount(uint256 minimumSend) private {
if (msg.value < minimumSend) {
revert AmountOfEthSentIsTooSmall(msg.value, minimumSend);
}
}
}
// SPDX-License-Identifier: GPL-2.0-or-later
// https://github.com/Uniswap/v3-periphery/blob/main/contracts/libraries/TransferHelper.sol
pragma solidity 0.8.19;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
library TransferHelper {
/// @notice Transfers tokens from the targeted address to the given destination
/// @notice Errors with 'STF' if transfer fails
/// @param token The contract address of the token to be transferred
/// @param from The originating address from which the tokens will be transferred
/// @param to The destination address of the transfer
/// @param value The amount to be transferred
function safeTransferFrom(address token, address from, address to, uint256 value) internal {
(bool success, bytes memory data) = token.call(
abi.encodeWithSelector(IERC20.transferFrom.selector, from, to, value)
);
require(success && (data.length == 0 || abi.decode(data, (bool))), "BP-STF");
}
/// @notice Transfers tokens from msg.sender to a recipient
/// @dev Errors with ST if transfer fails
/// @param token The contract address of the token which will be transferred
/// @param to The recipient of the transfer
/// @param value The value of the transfer
function safeTransfer(address token, address to, uint256 value) internal {
(bool success, bytes memory data) = token.call(
abi.encodeWithSelector(IERC20.transfer.selector, to, value)
);
require(success && (data.length == 0 || abi.decode(data, (bool))), "BP-ST");
}
function getBalance(address token) internal view returns (uint256 balance) {
bytes memory callData = abi.encodeWithSelector(IERC20.balanceOf.selector, address(this));
(bool success, bytes memory data) = token.staticcall(callData);
require(success && data.length >= 32);
balance = abi.decode(data, (uint256));
}
function getBalanceOf(address token, address target) internal view returns (uint256 balance) {
bytes memory callData = abi.encodeWithSelector(IERC20.balanceOf.selector, target);
(bool success, bytes memory data) = token.staticcall(callData);
require(success && data.length >= 32);
balance = abi.decode(data, (uint256));
}
function safeApprove(address token, address spender, uint256 amount) internal {
(bool success, bytes memory data) = token.call(
abi.encodeWithSelector(IERC20.approve.selector, spender, amount)
);
require(success && (data.length == 0 || abi.decode(data, (bool))), "BP-SA");
}
}