зеркало из https://github.com/mozilla/gecko-dev.git
88 строки
2.1 KiB
C++
88 строки
2.1 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 file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "mozilla/DebugOnly.h"
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#include "mozilla/MathAlgorithms.h"
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using mozilla::CeilingLog2;
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using mozilla::DebugOnly;
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using mozilla::FloorLog2;
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using mozilla::RoundUpPow2;
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static void
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TestCeiling()
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{
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for (uint32_t i = 0; i <= 1; i++)
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MOZ_ASSERT(CeilingLog2(i) == 0);
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for (uint32_t i = 2; i <= 2; i++)
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MOZ_ASSERT(CeilingLog2(i) == 1);
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for (uint32_t i = 3; i <= 4; i++)
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MOZ_ASSERT(CeilingLog2(i) == 2);
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for (uint32_t i = 5; i <= 8; i++)
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MOZ_ASSERT(CeilingLog2(i) == 3);
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for (uint32_t i = 9; i <= 16; i++)
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MOZ_ASSERT(CeilingLog2(i) == 4);
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}
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static void
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TestFloor()
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{
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for (uint32_t i = 0; i <= 1; i++)
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MOZ_ASSERT(FloorLog2(i) == 0);
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for (uint32_t i = 2; i <= 3; i++)
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MOZ_ASSERT(FloorLog2(i) == 1);
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for (uint32_t i = 4; i <= 7; i++)
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MOZ_ASSERT(FloorLog2(i) == 2);
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for (uint32_t i = 8; i <= 15; i++)
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MOZ_ASSERT(FloorLog2(i) == 3);
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for (uint32_t i = 16; i <= 31; i++)
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MOZ_ASSERT(FloorLog2(i) == 4);
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}
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static void
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TestRoundUpPow2()
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{
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MOZ_ASSERT(RoundUpPow2(0) == 1);
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MOZ_ASSERT(RoundUpPow2(1) == 1);
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MOZ_ASSERT(RoundUpPow2(2) == 2);
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MOZ_ASSERT(RoundUpPow2(3) == 4);
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MOZ_ASSERT(RoundUpPow2(4) == 4);
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MOZ_ASSERT(RoundUpPow2(5) == 8);
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MOZ_ASSERT(RoundUpPow2(6) == 8);
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MOZ_ASSERT(RoundUpPow2(7) == 8);
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MOZ_ASSERT(RoundUpPow2(8) == 8);
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MOZ_ASSERT(RoundUpPow2(9) == 16);
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MOZ_ASSERT(RoundUpPow2(15) == 16);
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MOZ_ASSERT(RoundUpPow2(16) == 16);
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MOZ_ASSERT(RoundUpPow2(17) == 32);
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MOZ_ASSERT(RoundUpPow2(31) == 32);
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MOZ_ASSERT(RoundUpPow2(32) == 32);
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MOZ_ASSERT(RoundUpPow2(33) == 64);
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DebugOnly<size_t> MaxPow2 = size_t(1) << (sizeof(size_t) * CHAR_BIT - 1);
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MOZ_ASSERT(RoundUpPow2(MaxPow2 - 1) == MaxPow2);
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MOZ_ASSERT(RoundUpPow2(MaxPow2) == MaxPow2);
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// not valid to round up when past the max power of two
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}
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int main()
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{
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TestCeiling();
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TestFloor();
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TestRoundUpPow2();
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return 0;
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}
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