44 lines
1.2 KiB
C++
44 lines
1.2 KiB
C++
/* -*- Mode: C++; tab-width: 20; 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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#ifndef MOZILLA_GFX_NUMERICTOOLS_H_
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#define MOZILLA_GFX_NUMERICTOOLS_H_
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namespace mozilla {
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// XXX - Move these into mfbt/MathAlgorithms.h?
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// Returns the largest multiple of aMultiplied that's <= x.
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// Same as int32_t(floor(double(x) / aMultiplier)) * aMultiplier,
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// but faster.
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inline int32_t
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RoundDownToMultiple(int32_t x, int32_t aMultiplier)
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{
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// We don't use float division + floor because that's hard for the compiler
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// to optimize.
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int mod = x % aMultiplier;
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if (x > 0) {
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return x - mod;
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}
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return mod ? x - aMultiplier - mod : x;
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}
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// Returns the smallest multiple of aMultiplied that's >= x.
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// Same as int32_t(ceil(double(x) / aMultiplier)) * aMultiplier,
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// but faster.
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inline int32_t
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RoundUpToMultiple(int32_t x, int32_t aMultiplier)
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{
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int mod = x % aMultiplier;
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if (x > 0) {
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return mod ? x + aMultiplier - mod : x;
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}
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return x - mod;
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}
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} // namespace mozilla
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#endif /* MOZILLA_GFX_NUMERICTOOLS_H_ */
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