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/*
* Copyright (C) 2014 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "safe_math.h"
#include <limits>
#include "gtest/gtest.h"
namespace art {
namespace interpreter {
TEST(SafeMath, Add) {
// Adding 1 overflows 0x7ff... to 0x800... aka max and min.
EXPECT_EQ(SafeAdd(std::numeric_limits<int32_t>::max(), 1),
std::numeric_limits<int32_t>::min());
EXPECT_EQ(SafeAdd(std::numeric_limits<int64_t>::max(), 1),
std::numeric_limits<int64_t>::min());
// Vanilla arithmetic should work too.
EXPECT_EQ(SafeAdd(std::numeric_limits<int32_t>::max() - 1, 1),
std::numeric_limits<int32_t>::max());
EXPECT_EQ(SafeAdd(std::numeric_limits<int64_t>::max() - 1, 1),
std::numeric_limits<int64_t>::max());
EXPECT_EQ(SafeAdd(std::numeric_limits<int32_t>::min() + 1, -1),
std::numeric_limits<int32_t>::min());
EXPECT_EQ(SafeAdd(std::numeric_limits<int64_t>::min() + 1, -1),
std::numeric_limits<int64_t>::min());
EXPECT_EQ(SafeAdd(int32_t(-1), -1), -2);
EXPECT_EQ(SafeAdd(int64_t(-1), -1), -2);
EXPECT_EQ(SafeAdd(int32_t(1), 1), 2);
EXPECT_EQ(SafeAdd(int64_t(1), 1), 2);
EXPECT_EQ(SafeAdd(int32_t(-1), 1), 0);
EXPECT_EQ(SafeAdd(int64_t(-1), 1), 0);
EXPECT_EQ(SafeAdd(int32_t(1), -1), 0);
EXPECT_EQ(SafeAdd(int64_t(1), -1), 0);
// Test sign extension of smaller operand sizes.
EXPECT_EQ(SafeAdd(int32_t(1), int8_t(-1)), 0);
EXPECT_EQ(SafeAdd(int64_t(1), int8_t(-1)), 0);
}
TEST(SafeMath, Sub) {
// Subtracting 1 underflows 0x800... to 0x7ff... aka min and max.
EXPECT_EQ(SafeSub(std::numeric_limits<int32_t>::min(), 1),
std::numeric_limits<int32_t>::max());
EXPECT_EQ(SafeSub(std::numeric_limits<int64_t>::min(), 1),
std::numeric_limits<int64_t>::max());
// Vanilla arithmetic should work too.
EXPECT_EQ(SafeSub(std::numeric_limits<int32_t>::max() - 1, -1),
std::numeric_limits<int32_t>::max());
EXPECT_EQ(SafeSub(std::numeric_limits<int64_t>::max() - 1, -1),
std::numeric_limits<int64_t>::max());
EXPECT_EQ(SafeSub(std::numeric_limits<int32_t>::min() + 1, 1),
std::numeric_limits<int32_t>::min());
EXPECT_EQ(SafeSub(std::numeric_limits<int64_t>::min() + 1, 1),
std::numeric_limits<int64_t>::min());
EXPECT_EQ(SafeSub(int32_t(-1), -1), 0);
EXPECT_EQ(SafeSub(int64_t(-1), -1), 0);
EXPECT_EQ(SafeSub(int32_t(1), 1), 0);
EXPECT_EQ(SafeSub(int64_t(1), 1), 0);
EXPECT_EQ(SafeSub(int32_t(-1), 1), -2);
EXPECT_EQ(SafeSub(int64_t(-1), 1), -2);
EXPECT_EQ(SafeSub(int32_t(1), -1), 2);
EXPECT_EQ(SafeSub(int64_t(1), -1), 2);
// Test sign extension of smaller operand sizes.
EXPECT_EQ(SafeAdd(int32_t(1), int8_t(-1)), 0);
EXPECT_EQ(SafeAdd(int64_t(1), int8_t(-1)), 0);
}
TEST(SafeMath, Mul) {
// Multiplying by 2 overflows 0x7ff...f to 0xfff...e aka max and -2.
EXPECT_EQ(SafeMul(std::numeric_limits<int32_t>::max(), 2),
-2);
EXPECT_EQ(SafeMul(std::numeric_limits<int64_t>::max(), 2),
-2);
// Vanilla arithmetic should work too.
EXPECT_EQ(SafeMul(std::numeric_limits<int32_t>::max() / 2, 2),
std::numeric_limits<int32_t>::max() - 1); // -1 as LSB is lost by division.
EXPECT_EQ(SafeMul(std::numeric_limits<int64_t>::max() / 2, 2),
std::numeric_limits<int64_t>::max() - 1); // -1 as LSB is lost by division.
EXPECT_EQ(SafeMul(std::numeric_limits<int32_t>::min() / 2, 2),
std::numeric_limits<int32_t>::min());
EXPECT_EQ(SafeMul(std::numeric_limits<int64_t>::min() / 2, 2),
std::numeric_limits<int64_t>::min());
EXPECT_EQ(SafeMul(int32_t(-1), -1), 1);
EXPECT_EQ(SafeMul(int64_t(-1), -1), 1);
EXPECT_EQ(SafeMul(int32_t(1), 1), 1);
EXPECT_EQ(SafeMul(int64_t(1), 1), 1);
EXPECT_EQ(SafeMul(int32_t(-1), 1), -1);
EXPECT_EQ(SafeMul(int64_t(-1), 1), -1);
EXPECT_EQ(SafeMul(int32_t(1), -1), -1);
EXPECT_EQ(SafeMul(int64_t(1), -1), -1);
// Test sign extension of smaller operand sizes.
EXPECT_EQ(SafeMul(int32_t(1), int8_t(-1)), -1);
EXPECT_EQ(SafeMul(int64_t(1), int8_t(-1)), -1);
}
} // namespace interpreter
} // namespace art
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