blob: c94cbc552550baa46085bd056c5aa8c76da5692a [file] [log] [blame]
// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This file contains the unit tests for the bit utilities.
#include "base/bits.h"
#include "build/build_config.h"
#include <limits>
#include "starboard/types.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace bits {
TEST(BitsTest, Log2Floor) {
EXPECT_EQ(-1, Log2Floor(0));
EXPECT_EQ(0, Log2Floor(1));
EXPECT_EQ(1, Log2Floor(2));
EXPECT_EQ(1, Log2Floor(3));
EXPECT_EQ(2, Log2Floor(4));
for (int i = 3; i < 31; ++i) {
unsigned int value = 1U << i;
EXPECT_EQ(i, Log2Floor(value));
EXPECT_EQ(i, Log2Floor(value + 1));
EXPECT_EQ(i, Log2Floor(value + 2));
EXPECT_EQ(i - 1, Log2Floor(value - 1));
EXPECT_EQ(i - 1, Log2Floor(value - 2));
}
EXPECT_EQ(31, Log2Floor(0xffffffffU));
}
TEST(BitsTest, Log2Ceiling) {
EXPECT_EQ(-1, Log2Ceiling(0));
EXPECT_EQ(0, Log2Ceiling(1));
EXPECT_EQ(1, Log2Ceiling(2));
EXPECT_EQ(2, Log2Ceiling(3));
EXPECT_EQ(2, Log2Ceiling(4));
for (int i = 3; i < 31; ++i) {
unsigned int value = 1U << i;
EXPECT_EQ(i, Log2Ceiling(value));
EXPECT_EQ(i + 1, Log2Ceiling(value + 1));
EXPECT_EQ(i + 1, Log2Ceiling(value + 2));
EXPECT_EQ(i, Log2Ceiling(value - 1));
EXPECT_EQ(i, Log2Ceiling(value - 2));
}
EXPECT_EQ(32, Log2Ceiling(0xffffffffU));
}
TEST(BitsTest, Align) {
const size_t kSizeTMax = std::numeric_limits<size_t>::max();
EXPECT_EQ(0ul, Align(0, 4));
EXPECT_EQ(4ul, Align(1, 4));
EXPECT_EQ(4096ul, Align(1, 4096));
EXPECT_EQ(4096ul, Align(4096, 4096));
EXPECT_EQ(4096ul, Align(4095, 4096));
EXPECT_EQ(8192ul, Align(4097, 4096));
EXPECT_EQ(kSizeTMax - 31, Align(kSizeTMax - 62, 32));
EXPECT_EQ(kSizeTMax / 2 + 1, Align(1, kSizeTMax / 2 + 1));
}
TEST(BitsTest, CountLeadingZeroBits8) {
EXPECT_EQ(8u, CountLeadingZeroBits(uint8_t{0}));
EXPECT_EQ(7u, CountLeadingZeroBits(uint8_t{1}));
for (uint8_t shift = 0; shift <= 7; shift++) {
EXPECT_EQ(7u - shift,
CountLeadingZeroBits(static_cast<uint8_t>(1 << shift)));
}
EXPECT_EQ(4u, CountLeadingZeroBits(uint8_t{0x0f}));
}
TEST(BitsTest, CountLeadingZeroBits16) {
EXPECT_EQ(16u, CountLeadingZeroBits(uint16_t{0}));
EXPECT_EQ(15u, CountLeadingZeroBits(uint16_t{1}));
for (uint16_t shift = 0; shift <= 15; shift++) {
EXPECT_EQ(15u - shift,
CountLeadingZeroBits(static_cast<uint16_t>(1 << shift)));
}
EXPECT_EQ(4u, CountLeadingZeroBits(uint16_t{0x0f0f}));
}
TEST(BitsTest, CountLeadingZeroBits32) {
EXPECT_EQ(32u, CountLeadingZeroBits(uint32_t{0}));
EXPECT_EQ(31u, CountLeadingZeroBits(uint32_t{1}));
for (uint32_t shift = 0; shift <= 31; shift++) {
EXPECT_EQ(31u - shift, CountLeadingZeroBits(uint32_t{1} << shift));
}
EXPECT_EQ(4u, CountLeadingZeroBits(uint32_t{0x0f0f0f0f}));
}
TEST(BitsTest, CountTrailingeZeroBits8) {
EXPECT_EQ(8u, CountTrailingZeroBits(uint8_t{0}));
EXPECT_EQ(7u, CountTrailingZeroBits(uint8_t{128}));
for (uint8_t shift = 0; shift <= 7; shift++) {
EXPECT_EQ(shift, CountTrailingZeroBits(static_cast<uint8_t>(1 << shift)));
}
EXPECT_EQ(4u, CountTrailingZeroBits(uint8_t{0xf0}));
}
TEST(BitsTest, CountTrailingeZeroBits16) {
EXPECT_EQ(16u, CountTrailingZeroBits(uint16_t{0}));
EXPECT_EQ(15u, CountTrailingZeroBits(uint16_t{32768}));
for (uint16_t shift = 0; shift <= 15; shift++) {
EXPECT_EQ(shift, CountTrailingZeroBits(static_cast<uint16_t>(1 << shift)));
}
EXPECT_EQ(4u, CountTrailingZeroBits(uint16_t{0xf0f0}));
}
TEST(BitsTest, CountTrailingeZeroBits32) {
EXPECT_EQ(32u, CountTrailingZeroBits(uint32_t{0}));
EXPECT_EQ(31u, CountTrailingZeroBits(uint32_t{1} << 31));
for (uint32_t shift = 0; shift <= 31; shift++) {
EXPECT_EQ(shift, CountTrailingZeroBits(uint32_t{1} << shift));
}
EXPECT_EQ(4u, CountTrailingZeroBits(uint32_t{0xf0f0f0f0}));
}
#if defined(ARCH_CPU_64_BITS)
TEST(BitsTest, CountLeadingZeroBits64) {
EXPECT_EQ(64u, CountLeadingZeroBits(uint64_t{0}));
EXPECT_EQ(63u, CountLeadingZeroBits(uint64_t{1}));
for (uint64_t shift = 0; shift <= 63; shift++) {
EXPECT_EQ(63u - shift, CountLeadingZeroBits(uint64_t{1} << shift));
}
EXPECT_EQ(4u, CountLeadingZeroBits(uint64_t{0x0f0f0f0f0f0f0f0f}));
}
TEST(BitsTest, CountTrailingeZeroBits64) {
EXPECT_EQ(64u, CountTrailingZeroBits(uint64_t{0}));
EXPECT_EQ(63u, CountTrailingZeroBits(uint64_t{1} << 63));
for (uint64_t shift = 0; shift <= 31; shift++) {
EXPECT_EQ(shift, CountTrailingZeroBits(uint64_t{1} << shift));
}
EXPECT_EQ(4u, CountTrailingZeroBits(uint64_t{0xf0f0f0f0f0f0f0f0}));
}
#endif // ARCH_CPU_64_BITS
TEST(BitsTest, CountLeadingZeroBitsSizeT) {
#if defined(ARCH_CPU_64_BITS)
EXPECT_EQ(64u, CountLeadingZeroBitsSizeT(size_t{0}));
EXPECT_EQ(63u, CountLeadingZeroBitsSizeT(size_t{1}));
EXPECT_EQ(32u, CountLeadingZeroBitsSizeT(size_t{1} << 31));
EXPECT_EQ(1u, CountLeadingZeroBitsSizeT(size_t{1} << 62));
EXPECT_EQ(0u, CountLeadingZeroBitsSizeT(size_t{1} << 63));
#else
EXPECT_EQ(32u, CountLeadingZeroBitsSizeT(size_t{0}));
EXPECT_EQ(31u, CountLeadingZeroBitsSizeT(size_t{1}));
EXPECT_EQ(1u, CountLeadingZeroBitsSizeT(size_t{1} << 30));
EXPECT_EQ(0u, CountLeadingZeroBitsSizeT(size_t{1} << 31));
#endif // ARCH_CPU_64_BITS
}
TEST(BitsTest, CountTrailingZeroBitsSizeT) {
#if defined(ARCH_CPU_64_BITS)
EXPECT_EQ(64u, CountTrailingZeroBitsSizeT(size_t{0}));
EXPECT_EQ(63u, CountTrailingZeroBitsSizeT(size_t{1} << 63));
EXPECT_EQ(31u, CountTrailingZeroBitsSizeT(size_t{1} << 31));
EXPECT_EQ(1u, CountTrailingZeroBitsSizeT(size_t{2}));
EXPECT_EQ(0u, CountTrailingZeroBitsSizeT(size_t{1}));
#else
EXPECT_EQ(32u, CountTrailingZeroBitsSizeT(size_t{0}));
EXPECT_EQ(31u, CountTrailingZeroBitsSizeT(size_t{1} << 31));
EXPECT_EQ(1u, CountTrailingZeroBitsSizeT(size_t{2}));
EXPECT_EQ(0u, CountTrailingZeroBitsSizeT(size_t{1}));
#endif // ARCH_CPU_64_BITS
}
TEST(BitsTest, PowerOfTwo) {
EXPECT_FALSE(IsPowerOfTwo(-1));
EXPECT_FALSE(IsPowerOfTwo(0));
EXPECT_TRUE(IsPowerOfTwo(1));
EXPECT_TRUE(IsPowerOfTwo(2));
// Unsigned 64 bit cases.
for (uint32_t i = 2; i < 64; i++) {
const uint64_t val = uint64_t{1} << i;
EXPECT_FALSE(IsPowerOfTwo(val - 1));
EXPECT_TRUE(IsPowerOfTwo(val));
EXPECT_FALSE(IsPowerOfTwo(val + 1));
}
// Signed 64 bit cases.
for (uint32_t i = 2; i < 63; i++) {
const int64_t val = int64_t{1} << i;
EXPECT_FALSE(IsPowerOfTwo(val - 1));
EXPECT_TRUE(IsPowerOfTwo(val));
EXPECT_FALSE(IsPowerOfTwo(val + 1));
}
// Signed integers with only the last bit set are negative, not powers of two.
EXPECT_FALSE(IsPowerOfTwo(int64_t{1} << 63));
}
} // namespace bits
} // namespace base