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
TEST(BitsTest,Log2Floor)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
TEST(BitsTest,Log2Ceiling)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
49