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48 lines
1.1 KiB
C++
48 lines
1.1 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* mfbt maths algorithms. */
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#ifndef mozilla_MathAlgorithms_h_
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#define mozilla_MathAlgorithms_h_
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#include "mozilla/Assertions.h"
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namespace mozilla {
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// Greatest Common Divisor
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template<typename IntegerType>
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MOZ_ALWAYS_INLINE IntegerType
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EuclidGCD(IntegerType a, IntegerType b)
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{
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// Euclid's algorithm; O(N) in the worst case. (There are better
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// ways, but we don't need them for the current use of this algo.)
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MOZ_ASSERT(a > 0);
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MOZ_ASSERT(b > 0);
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while (a != b) {
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if (a > b) {
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a = a - b;
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} else {
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b = b - a;
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}
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}
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return a;
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}
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// Least Common Multiple
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template<typename IntegerType>
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MOZ_ALWAYS_INLINE IntegerType
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EuclidLCM(IntegerType a, IntegerType b)
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{
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// Divide first to reduce overflow risk.
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return (a / EuclidGCD(a, b)) * b;
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}
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} /* namespace mozilla */
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#endif /* mozilla_MathAlgorithms_h_ */
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