// SPDX-License-Identifier: MIT // OpenZeppelin Contracts (last updated v5.0.0) (utils/math/Math.sol) pragma solidity ^0.8.20; /** * @dev Standard math utilities missing in the Solidity language. */ library Math { /** * @dev Muldiv operation overflow. */ error MathOverflowedMulDiv(); enum Rounding { Floor, // Toward negative infinity Ceil, // Toward positive infinity Trunc, // Toward zero Expand // Away from zero } /** * @dev Returns the addition of two unsigned integers, with an overflow flag. */ function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) { unchecked { uint256 c = a + b; if (c < a) return (false, 0); return (true, c); } } /** * @dev Returns the subtraction of two unsigned integers, with an overflow flag. */ function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) { unchecked { if (b > a) return (false, 0); return (true, a - b); } } /** * @dev Returns the multiplication of two unsigned integers, with an overflow flag. */ function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) { unchecked { // Gas optimization: this is cheaper than requiring 'a' not being zero, but the // benefit is lost if 'b' is also tested. // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522 if (a == 0) return (true, 0); uint256 c = a * b; if (c / a != b) return (false, 0); return (true, c); } } /** * @dev Returns the division of two unsigned integers, with a division by zero flag. */ function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) { unchecked { if (b == 0) return (false, 0); return (true, a / b); } } /** * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag. */ function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) { unchecked { if (b == 0) return (false, 0); return (true, a % b); } } /** * @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 towards infinity instead * of rounding towards zero. */ function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) { if (b == 0) { // Guarantee the same behavior as in a regular Solidity division. return a / b; } // (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 = x * y; // Least significant 256 bits of the product uint256 prod1; // Most significant 256 bits of the product assembly { let mm := mulmod(x, y, not(0)) 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. if (denominator <= prod1) { revert MathOverflowedMulDiv(); } /////////////////////////////////////////////// // 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. uint256 twos = denominator & (0 - denominator); 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 (unsignedRoundsUp(rounding) && 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 * towards zero. * * 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 + (unsignedRoundsUp(rounding) && result * result < a ? 1 : 0); } } /** * @dev Return the log in base 2 of a positive value rounded towards zero. * 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 + (unsignedRoundsUp(rounding) && 1 << result < value ? 1 : 0); } } /** * @dev Return the log in base 10 of a positive value rounded towards zero. * 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 + (unsignedRoundsUp(rounding) && 10 ** result < value ? 1 : 0); } } /** * @dev Return the log in base 256 of a positive value rounded towards zero. * 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 + (unsignedRoundsUp(rounding) && 1 << (result << 3) < value ? 1 : 0); } } /** * @dev Returns whether a provided rounding mode is considered rounding up for unsigned integers. */ function unsignedRoundsUp(Rounding rounding) internal pure returns (bool) { return uint8(rounding) % 2 == 1; } }

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