49 lines
1.4 KiB
C++
49 lines
1.4 KiB
C++
// Copyright (c) 2009 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// This file contains the unit tests for the bit utilities.
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#include "base/bits.h"
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#include "testing/gtest/include/gtest/gtest.h"
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namespace base {
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namespace bits {
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TEST(BitsTest, Log2Floor) {
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EXPECT_EQ(-1, Log2Floor(0));
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EXPECT_EQ(0, Log2Floor(1));
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EXPECT_EQ(1, Log2Floor(2));
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EXPECT_EQ(1, Log2Floor(3));
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EXPECT_EQ(2, Log2Floor(4));
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for (int i = 3; i < 31; ++i) {
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unsigned int value = 1U << i;
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EXPECT_EQ(i, Log2Floor(value));
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EXPECT_EQ(i, Log2Floor(value + 1));
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EXPECT_EQ(i, Log2Floor(value + 2));
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EXPECT_EQ(i - 1, Log2Floor(value - 1));
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EXPECT_EQ(i - 1, Log2Floor(value - 2));
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}
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EXPECT_EQ(31, Log2Floor(0xffffffffU));
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}
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TEST(BitsTest, Log2Ceiling) {
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EXPECT_EQ(-1, Log2Ceiling(0));
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EXPECT_EQ(0, Log2Ceiling(1));
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EXPECT_EQ(1, Log2Ceiling(2));
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EXPECT_EQ(2, Log2Ceiling(3));
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EXPECT_EQ(2, Log2Ceiling(4));
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for (int i = 3; i < 31; ++i) {
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unsigned int value = 1U << i;
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EXPECT_EQ(i, Log2Ceiling(value));
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EXPECT_EQ(i + 1, Log2Ceiling(value + 1));
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EXPECT_EQ(i + 1, Log2Ceiling(value + 2));
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EXPECT_EQ(i, Log2Ceiling(value - 1));
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EXPECT_EQ(i, Log2Ceiling(value - 2));
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}
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EXPECT_EQ(32, Log2Ceiling(0xffffffffU));
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}
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} // namespace bits
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} // namespace base
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