Patrick Scott | c7f5f85 | 2010-02-04 10:37:17 -0500 | [diff] [blame] | 1 | // Copyright (c) 2009 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | // This file contains the unit tests for the bit utilities. |
| 6 | |
| 7 | #include "base/bits.h" |
| 8 | #include "testing/gtest/include/gtest/gtest.h" |
| 9 | |
| 10 | namespace base { |
| 11 | namespace bits { |
| 12 | |
| 13 | TEST(BitsTest, Log2Floor) { |
| 14 | EXPECT_EQ(-1, Log2Floor(0)); |
| 15 | EXPECT_EQ(0, Log2Floor(1)); |
| 16 | EXPECT_EQ(1, Log2Floor(2)); |
| 17 | EXPECT_EQ(1, Log2Floor(3)); |
| 18 | EXPECT_EQ(2, Log2Floor(4)); |
| 19 | for (int i = 3; i < 31; ++i) { |
| 20 | unsigned int value = 1U << i; |
| 21 | EXPECT_EQ(i, Log2Floor(value)); |
| 22 | EXPECT_EQ(i, Log2Floor(value + 1)); |
| 23 | EXPECT_EQ(i, Log2Floor(value + 2)); |
| 24 | EXPECT_EQ(i - 1, Log2Floor(value - 1)); |
| 25 | EXPECT_EQ(i - 1, Log2Floor(value - 2)); |
| 26 | } |
| 27 | EXPECT_EQ(31, Log2Floor(0xffffffffU)); |
| 28 | } |
| 29 | |
| 30 | TEST(BitsTest, Log2Ceiling) { |
| 31 | EXPECT_EQ(-1, Log2Ceiling(0)); |
| 32 | EXPECT_EQ(0, Log2Ceiling(1)); |
| 33 | EXPECT_EQ(1, Log2Ceiling(2)); |
| 34 | EXPECT_EQ(2, Log2Ceiling(3)); |
| 35 | EXPECT_EQ(2, Log2Ceiling(4)); |
| 36 | for (int i = 3; i < 31; ++i) { |
| 37 | unsigned int value = 1U << i; |
| 38 | EXPECT_EQ(i, Log2Ceiling(value)); |
| 39 | EXPECT_EQ(i + 1, Log2Ceiling(value + 1)); |
| 40 | EXPECT_EQ(i + 1, Log2Ceiling(value + 2)); |
| 41 | EXPECT_EQ(i, Log2Ceiling(value - 1)); |
| 42 | EXPECT_EQ(i, Log2Ceiling(value - 2)); |
| 43 | } |
| 44 | EXPECT_EQ(32, Log2Ceiling(0xffffffffU)); |
| 45 | } |
| 46 | |
| 47 | } // namespace bits |
| 48 | } // namespace base |