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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 "butil/bits.h"
- #include <gtest/gtest.h>
- namespace butil {
- 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));
- }
- } // namespace bits
- } // namespace butil
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