44 lines
1.3 KiB
Solidity
44 lines
1.3 KiB
Solidity
// SPDX-License-Identifier: MIT
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pragma solidity >=0.6.2 <0.9.0;
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library stdMath {
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int256 private constant INT256_MIN = -57896044618658097711785492504343953926634992332820282019728792003956564819968;
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function abs(int256 a) internal pure returns (uint256) {
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// Required or it will fail when `a = type(int256).min`
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if (a == INT256_MIN) {
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return 57896044618658097711785492504343953926634992332820282019728792003956564819968;
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}
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return uint256(a > 0 ? a : -a);
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}
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function delta(uint256 a, uint256 b) internal pure returns (uint256) {
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return a > b ? a - b : b - a;
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}
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function delta(int256 a, int256 b) internal pure returns (uint256) {
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// a and b are of the same sign
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// this works thanks to two's complement, the left-most bit is the sign bit
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if ((a ^ b) > -1) {
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return delta(abs(a), abs(b));
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}
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// a and b are of opposite signs
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return abs(a) + abs(b);
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}
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function percentDelta(uint256 a, uint256 b) internal pure returns (uint256) {
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uint256 absDelta = delta(a, b);
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return absDelta * 1e18 / b;
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}
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function percentDelta(int256 a, int256 b) internal pure returns (uint256) {
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uint256 absDelta = delta(a, b);
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uint256 absB = abs(b);
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return absDelta * 1e18 / absB;
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}
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}
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