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// Copyright 2016 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.
#include <limits>
#include "base/logging.h"
#include "base/macros.h"
#include "base/numerics/saturated_arithmetic.h"
#include "build/build_config.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
TEST(SaturatedArithmeticTest, Addition) {
int int_max = std::numeric_limits<int>::max();
int int_min = std::numeric_limits<int>::min();
EXPECT_EQ(0, SaturatedAddition(0, 0));
EXPECT_EQ(1, SaturatedAddition(0, 1));
EXPECT_EQ(100, SaturatedAddition(0, 100));
EXPECT_EQ(150, SaturatedAddition(100, 50));
EXPECT_EQ(-1, SaturatedAddition(0, -1));
EXPECT_EQ(0, SaturatedAddition(1, -1));
EXPECT_EQ(50, SaturatedAddition(100, -50));
EXPECT_EQ(-50, SaturatedAddition(50, -100));
EXPECT_EQ(int_max - 1, SaturatedAddition(int_max - 1, 0));
EXPECT_EQ(int_max, SaturatedAddition(int_max - 1, 1));
EXPECT_EQ(int_max, SaturatedAddition(int_max - 1, 2));
EXPECT_EQ(int_max - 1, SaturatedAddition(0, int_max - 1));
EXPECT_EQ(int_max, SaturatedAddition(1, int_max - 1));
EXPECT_EQ(int_max, SaturatedAddition(2, int_max - 1));
EXPECT_EQ(int_max, SaturatedAddition(int_max - 1, int_max - 1));
EXPECT_EQ(int_max, SaturatedAddition(int_max, int_max));
EXPECT_EQ(int_min, SaturatedAddition(int_min, 0));
EXPECT_EQ(int_min + 1, SaturatedAddition(int_min + 1, 0));
EXPECT_EQ(int_min + 2, SaturatedAddition(int_min + 1, 1));
EXPECT_EQ(int_min + 3, SaturatedAddition(int_min + 1, 2));
EXPECT_EQ(int_min, SaturatedAddition(int_min + 1, -1));
EXPECT_EQ(int_min, SaturatedAddition(int_min + 1, -2));
EXPECT_EQ(int_min + 1, SaturatedAddition(0, int_min + 1));
EXPECT_EQ(int_min, SaturatedAddition(-1, int_min + 1));
EXPECT_EQ(int_min, SaturatedAddition(-2, int_min + 1));
EXPECT_EQ(int_max / 2 + 10000, SaturatedAddition(int_max / 2, 10000));
EXPECT_EQ(int_max, SaturatedAddition(int_max / 2 + 1, int_max / 2 + 1));
EXPECT_EQ(-1, SaturatedAddition(int_min, int_max));
}
TEST(SaturatedArithmeticTest, Subtraction) {
int int_max = std::numeric_limits<int>::max();
int int_min = std::numeric_limits<int>::min();
EXPECT_EQ(0, SaturatedSubtraction(0, 0));
EXPECT_EQ(-1, SaturatedSubtraction(0, 1));
EXPECT_EQ(-100, SaturatedSubtraction(0, 100));
EXPECT_EQ(50, SaturatedSubtraction(100, 50));
EXPECT_EQ(1, SaturatedSubtraction(0, -1));
EXPECT_EQ(2, SaturatedSubtraction(1, -1));
EXPECT_EQ(150, SaturatedSubtraction(100, -50));
EXPECT_EQ(150, SaturatedSubtraction(50, -100));
EXPECT_EQ(int_max, SaturatedSubtraction(int_max, 0));
EXPECT_EQ(int_max - 1, SaturatedSubtraction(int_max, 1));
EXPECT_EQ(int_max - 1, SaturatedSubtraction(int_max - 1, 0));
EXPECT_EQ(int_max, SaturatedSubtraction(int_max - 1, -1));
EXPECT_EQ(int_max, SaturatedSubtraction(int_max - 1, -2));
EXPECT_EQ(-int_max + 1, SaturatedSubtraction(0, int_max - 1));
EXPECT_EQ(-int_max, SaturatedSubtraction(-1, int_max - 1));
EXPECT_EQ(-int_max - 1, SaturatedSubtraction(-2, int_max - 1));
EXPECT_EQ(-int_max - 1, SaturatedSubtraction(-3, int_max - 1));
EXPECT_EQ(int_min, SaturatedSubtraction(int_min, 0));
EXPECT_EQ(int_min + 1, SaturatedSubtraction(int_min + 1, 0));
EXPECT_EQ(int_min, SaturatedSubtraction(int_min + 1, 1));
EXPECT_EQ(int_min, SaturatedSubtraction(int_min + 1, 2));
EXPECT_EQ(0, SaturatedSubtraction(int_min, int_min));
EXPECT_EQ(0, SaturatedSubtraction(int_max, int_max));
EXPECT_EQ(int_max, SaturatedSubtraction(int_max, int_min));
}
TEST(SaturatedArithmeticTest, SetSigned) {
int int_max = std::numeric_limits<int>::max();
int int_min = std::numeric_limits<int>::min();
const int kFractionBits = 6;
const int kIntMaxForLayoutUnit = int_max >> kFractionBits;
const int kIntMinForLayoutUnit = int_min >> kFractionBits;
EXPECT_EQ(0, SaturatedSet<kFractionBits>(0));
// Internally the max number we can represent (without saturating)
// is all the (non-sign) bits set except for the bottom n fraction bits
const int max_internal_representation = int_max ^ ((1 << kFractionBits) - 1);
EXPECT_EQ(max_internal_representation,
SaturatedSet<kFractionBits>(kIntMaxForLayoutUnit));
EXPECT_EQ(GetMaxSaturatedSetResultForTesting(kFractionBits),
SaturatedSet<kFractionBits>(kIntMaxForLayoutUnit + 100));
EXPECT_EQ((kIntMaxForLayoutUnit - 100) << kFractionBits,
SaturatedSet<kFractionBits>(kIntMaxForLayoutUnit - 100));
EXPECT_EQ(GetMinSaturatedSetResultForTesting(kFractionBits),
SaturatedSet<kFractionBits>(kIntMinForLayoutUnit));
EXPECT_EQ(GetMinSaturatedSetResultForTesting(kFractionBits),
SaturatedSet<kFractionBits>(kIntMinForLayoutUnit - 100));
// Shifting negative numbers left has undefined behavior, so use
// multiplication instead of direct shifting here.
EXPECT_EQ((kIntMinForLayoutUnit + 100) * (1 << kFractionBits),
SaturatedSet<kFractionBits>(kIntMinForLayoutUnit + 100));
}
TEST(SaturatedArithmeticTest, SetUnsigned) {
int int_max = std::numeric_limits<int>::max();
const int kFractionBits = 6;
const int kIntMaxForLayoutUnit = int_max >> kFractionBits;
EXPECT_EQ(0, SaturatedSet<kFractionBits>((unsigned)0));
EXPECT_EQ(GetMaxSaturatedSetResultForTesting(kFractionBits),
SaturatedSet<kFractionBits>((unsigned)kIntMaxForLayoutUnit));
const unsigned kOverflowed = kIntMaxForLayoutUnit + 100;
EXPECT_EQ(GetMaxSaturatedSetResultForTesting(kFractionBits),
SaturatedSet<kFractionBits>(kOverflowed));
const unsigned kNotOverflowed = kIntMaxForLayoutUnit - 100;
EXPECT_EQ((kIntMaxForLayoutUnit - 100) << kFractionBits,
SaturatedSet<kFractionBits>(kNotOverflowed));
}
} // namespace base
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