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/*
* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/numerics/mod_ops.h"
#include <stdint.h>
#include "test/gtest.h"
namespace webrtc {
class TestModOps : public ::testing::Test {
protected:
// Can't use std::numeric_limits<unsigned long>::max() since
// MSVC doesn't support constexpr.
static const unsigned long ulmax = ~0ul; // NOLINT
};
TEST_F(TestModOps, Add) {
const int D = 100;
ASSERT_EQ(1u, Add<D>(0, 1));
ASSERT_EQ(0u, Add<D>(0, D));
for (int i = 0; i < D; ++i)
ASSERT_EQ(0u, Add<D>(i, D - i));
int t = 37;
uint8_t a = t;
for (int i = 0; i < 256; ++i) {
ASSERT_EQ(a, static_cast<uint8_t>(t));
t = Add<256>(t, 1);
++a;
}
}
TEST_F(TestModOps, AddLarge) {
const unsigned long D = ulmax - 10ul; // NOLINT
unsigned long l = D - 1ul; // NOLINT
ASSERT_EQ(D - 2ul, Add<D>(l, l));
ASSERT_EQ(9ul, Add<D>(l, ulmax));
ASSERT_EQ(10ul, Add<D>(0ul, ulmax));
}
TEST_F(TestModOps, Subtract) {
const int D = 100;
ASSERT_EQ(99u, Subtract<D>(0, 1));
ASSERT_EQ(0u, Subtract<D>(0, D));
for (int i = 0; i < D; ++i)
ASSERT_EQ(0u, Subtract<D>(i, D + i));
int t = 37;
uint8_t a = t;
for (int i = 0; i < 256; ++i) {
ASSERT_EQ(a, static_cast<uint8_t>(t));
t = Subtract<256>(t, 1);
--a;
}
}
TEST_F(TestModOps, SubtractLarge) {
// NOLINTNEXTLINE
const unsigned long D = ulmax - 10ul; // NOLINT
unsigned long l = D - 1ul; // NOLINT
ASSERT_EQ(0ul, Subtract<D>(l, l));
ASSERT_EQ(D - 11ul, Subtract<D>(l, ulmax));
ASSERT_EQ(D - 10ul, Subtract<D>(0ul, ulmax));
}
TEST_F(TestModOps, ForwardDiff) {
ASSERT_EQ(0u, ForwardDiff(4711u, 4711u));
uint8_t x = 0;
uint8_t y = 255;
for (int i = 0; i < 256; ++i) {
ASSERT_EQ(255u, ForwardDiff(x, y));
++x;
++y;
}
int yi = 255;
for (int i = 0; i < 256; ++i) {
ASSERT_EQ(255u, ForwardDiff<uint8_t>(x, yi));
++x;
++yi;
}
}
TEST_F(TestModOps, ForwardDiffWithDivisor) {
ASSERT_EQ(122, (ForwardDiff<uint8_t, 123>(0, 122)));
ASSERT_EQ(0, (ForwardDiff<uint8_t, 123>(122, 122)));
ASSERT_EQ(122, (ForwardDiff<uint8_t, 123>(1, 0)));
ASSERT_EQ(0, (ForwardDiff<uint8_t, 123>(0, 0)));
ASSERT_EQ(1, (ForwardDiff<uint8_t, 123>(122, 0)));
}
TEST_F(TestModOps, ReverseDiff) {
ASSERT_EQ(0u, ReverseDiff(4711u, 4711u));
uint8_t x = 0;
uint8_t y = 255;
for (int i = 0; i < 256; ++i) {
ASSERT_EQ(1u, ReverseDiff(x, y));
++x;
++y;
}
int yi = 255;
for (int i = 0; i < 256; ++i) {
ASSERT_EQ(1u, ReverseDiff<uint8_t>(x, yi));
++x;
++yi;
}
}
TEST_F(TestModOps, ReverseDiffWithDivisor) {
ASSERT_EQ(1, (ReverseDiff<uint8_t, 123>(0, 122)));
ASSERT_EQ(0, (ReverseDiff<uint8_t, 123>(122, 122)));
ASSERT_EQ(1, (ReverseDiff<uint8_t, 123>(1, 0)));
ASSERT_EQ(0, (ReverseDiff<uint8_t, 123>(0, 0)));
ASSERT_EQ(122, (ReverseDiff<uint8_t, 123>(122, 0)));
}
TEST_F(TestModOps, MinDiff) {
for (uint16_t i = 0; i < 256; ++i) {
ASSERT_EQ(0, MinDiff<uint8_t>(i, i));
ASSERT_EQ(1, MinDiff<uint8_t>(i - 1, i));
ASSERT_EQ(1, MinDiff<uint8_t>(i + 1, i));
}
for (uint8_t i = 0; i < 128; ++i)
ASSERT_EQ(i, MinDiff<uint8_t>(0, i));
for (uint8_t i = 0; i < 128; ++i)
ASSERT_EQ(128 - i, MinDiff<uint8_t>(0, 128 + i));
}
TEST_F(TestModOps, MinDiffWitDivisor) {
ASSERT_EQ(5u, (MinDiff<uint8_t, 11>(0, 5)));
ASSERT_EQ(5u, (MinDiff<uint8_t, 11>(0, 6)));
ASSERT_EQ(5u, (MinDiff<uint8_t, 11>(5, 0)));
ASSERT_EQ(5u, (MinDiff<uint8_t, 11>(6, 0)));
const uint16_t D = 4711;
for (uint16_t i = 0; i < D / 2; ++i)
ASSERT_EQ(i, (MinDiff<uint16_t, D>(0, i)));
ASSERT_EQ(D / 2, (MinDiff<uint16_t, D>(0, D / 2)));
for (uint16_t i = 0; i < D / 2; ++i)
ASSERT_EQ(D / 2 - i, (MinDiff<uint16_t, D>(0, D / 2 - i)));
}
} // namespace webrtc
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