gecko-dev/mfbt/tests/TestCeilingFloor.cpp
Jeff Walden cea309af82 Bug 895792 - Fix RoundUpPow2's required precondition to not be wrong. r=terrence
--HG--
extra : rebase_source : e42420628dad8b8e9fe37287fa8e08eb262fe615
2013-07-25 20:01:45 -07:00

86 lines
2.1 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/MathAlgorithms.h"
using mozilla::CeilingLog2;
using mozilla::FloorLog2;
using mozilla::RoundUpPow2;
static void
TestCeiling()
{
for (uint32_t i = 0; i <= 1; i++)
MOZ_ASSERT(CeilingLog2(i) == 0);
for (uint32_t i = 2; i <= 2; i++)
MOZ_ASSERT(CeilingLog2(i) == 1);
for (uint32_t i = 3; i <= 4; i++)
MOZ_ASSERT(CeilingLog2(i) == 2);
for (uint32_t i = 5; i <= 8; i++)
MOZ_ASSERT(CeilingLog2(i) == 3);
for (uint32_t i = 9; i <= 16; i++)
MOZ_ASSERT(CeilingLog2(i) == 4);
}
static void
TestFloor()
{
for (uint32_t i = 0; i <= 1; i++)
MOZ_ASSERT(FloorLog2(i) == 0);
for (uint32_t i = 2; i <= 3; i++)
MOZ_ASSERT(FloorLog2(i) == 1);
for (uint32_t i = 4; i <= 7; i++)
MOZ_ASSERT(FloorLog2(i) == 2);
for (uint32_t i = 8; i <= 15; i++)
MOZ_ASSERT(FloorLog2(i) == 3);
for (uint32_t i = 16; i <= 31; i++)
MOZ_ASSERT(FloorLog2(i) == 4);
}
static void
TestRoundUpPow2()
{
MOZ_ASSERT(RoundUpPow2(0) == 1);
MOZ_ASSERT(RoundUpPow2(1) == 1);
MOZ_ASSERT(RoundUpPow2(2) == 2);
MOZ_ASSERT(RoundUpPow2(3) == 4);
MOZ_ASSERT(RoundUpPow2(4) == 4);
MOZ_ASSERT(RoundUpPow2(5) == 8);
MOZ_ASSERT(RoundUpPow2(6) == 8);
MOZ_ASSERT(RoundUpPow2(7) == 8);
MOZ_ASSERT(RoundUpPow2(8) == 8);
MOZ_ASSERT(RoundUpPow2(9) == 16);
MOZ_ASSERT(RoundUpPow2(15) == 16);
MOZ_ASSERT(RoundUpPow2(16) == 16);
MOZ_ASSERT(RoundUpPow2(17) == 32);
MOZ_ASSERT(RoundUpPow2(31) == 32);
MOZ_ASSERT(RoundUpPow2(32) == 32);
MOZ_ASSERT(RoundUpPow2(33) == 64);
size_t MaxPow2 = size_t(1) << (sizeof(size_t) * CHAR_BIT - 1);
MOZ_ASSERT(RoundUpPow2(MaxPow2 - 1) == MaxPow2);
MOZ_ASSERT(RoundUpPow2(MaxPow2) == MaxPow2);
// not valid to round up when past the max power of two
}
int main()
{
TestCeiling();
TestFloor();
TestRoundUpPow2();
return 0;
}