| // 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 <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 |