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// 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 <stddef.h>
#include <limits>
#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));
}
} // namespace bits
} // namespace base
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