dfae50fa5b
Co-authored-by: Francisco Giordano <fg@frang.io> Co-authored-by: Hadrien Croubois <hadrien.croubois@gmail.com> Co-authored-by: ernestognw <ernestognw@gmail.com>
51 lines
1.8 KiB
Solidity
51 lines
1.8 KiB
Solidity
// SPDX-License-Identifier: MIT
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// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/SignedMath.sol)
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pragma solidity ^0.8.20;
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/**
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* @dev Standard signed math utilities missing in the Solidity language.
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*/
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library SignedMath {
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/**
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* @dev Returns the largest of two signed numbers.
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*/
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function max(int256 a, int256 b) internal pure returns (int256) {
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return a > b ? a : b;
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}
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/**
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* @dev Returns the smallest of two signed numbers.
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*/
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function min(int256 a, int256 b) internal pure returns (int256) {
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return a < b ? a : b;
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}
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/**
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* @dev Returns the average of two signed numbers without overflow.
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* The result is rounded towards zero.
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*/
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function average(int256 a, int256 b) internal pure returns (int256) {
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// Formula from the book "Hacker's Delight"
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int256 x = (a & b) + ((a ^ b) >> 1);
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return x + (int256(uint256(x) >> 255) & (a ^ b));
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}
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/**
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* @dev Returns the absolute unsigned value of a signed value.
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*/
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function abs(int256 n) internal pure returns (uint256) {
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unchecked {
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// Formula from the "Bit Twiddling Hacks" by Sean Eron Anderson.
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// Since `n` is a signed integer, the generated bytecode will use the SAR opcode to perform the right shift,
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// taking advantage of the most significant (or "sign" bit) in two's complement representation.
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// This opcode adds new most significant bits set to the value of the previous most significant bit. As a result,
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// the mask will either be `bytes(0)` (if n is positive) or `~bytes32(0)` (if n is negative).
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int256 mask = n >> 255;
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// A `bytes(0)` mask leaves the input unchanged, while a `~bytes32(0)` mask complements it.
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return uint256((n + mask) ^ mask);
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}
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}
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}
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