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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
#include <mozilla/Saturate.h>
#include <mozilla/Assertions.h>
#include <limits>
using mozilla::detail::Saturate;
#define A(a) MOZ_RELEASE_ASSERT(a, "Test \'" #a "\' failed.")
static const unsigned long sNumOps = 32;
template <typename T>
static T StartValue() {
// Specialize |StartValue| for the given type.
A(false);
}
template <>
int8_t StartValue<int8_t>() {
return 0;
}
template <>
int16_t StartValue<int16_t>() {
return 0;
}
template <>
int32_t StartValue<int32_t>() {
return 0;
}
template <>
uint8_t StartValue<uint8_t>() {
// Picking a value near middle of uint8_t's range.
return static_cast<uint8_t>(std::numeric_limits<int8_t>::max());
}
template <>
uint16_t StartValue<uint16_t>() {
// Picking a value near middle of uint16_t's range.
return static_cast<uint8_t>(std::numeric_limits<int16_t>::max());
}
template <>
uint32_t StartValue<uint32_t>() {
// Picking a value near middle of uint32_t's range.
return static_cast<uint8_t>(std::numeric_limits<int32_t>::max());
}
// Add
//
template <typename T>
static void TestPrefixIncr() {
T value = StartValue<T>();
Saturate<T> satValue(value);
for (T i = 0; i < static_cast<T>(sNumOps); ++i) {
A(++value == ++satValue);
}
}
template <typename T>
static void TestPostfixIncr() {
T value = StartValue<T>();
Saturate<T> satValue(value);
for (T i = 0; i < static_cast<T>(sNumOps); ++i) {
A(value++ == satValue++);
}
}
template <typename T>
static void TestAdd() {
T value = StartValue<T>();
Saturate<T> satValue(value);
for (T i = 0; i < static_cast<T>(sNumOps); ++i) {
A((value + i) == (satValue + i));
}
}
// Subtract
//
template <typename T>
static void TestPrefixDecr() {
T value = StartValue<T>();
Saturate<T> satValue(value);
for (T i = 0; i < static_cast<T>(sNumOps); ++i) {
A(--value == --satValue);
}
}
template <typename T>
static void TestPostfixDecr() {
T value = StartValue<T>();
Saturate<T> satValue(value);
for (T i = 0; i < static_cast<T>(sNumOps); ++i) {
A(value-- == satValue--);
}
}
template <typename T>
static void TestSub() {
T value = StartValue<T>();
Saturate<T> satValue(value);
for (T i = 0; i < static_cast<T>(sNumOps); ++i) {
A((value - i) == (satValue - i));
}
}
// Corner cases near bounds
//
template <typename T>
static void TestUpperBound() {
Saturate<T> satValue(std::numeric_limits<T>::max());
A(--satValue == (std::numeric_limits<T>::max() - 1));
A(++satValue == (std::numeric_limits<T>::max()));
A(++satValue == (std::numeric_limits<T>::max())); // don't overflow here
A(++satValue == (std::numeric_limits<T>::max())); // don't overflow here
A(--satValue == (std::numeric_limits<T>::max() - 1)); // back at (max - 1)
A(--satValue == (std::numeric_limits<T>::max() - 2));
}
template <typename T>
static void TestLowerBound() {
Saturate<T> satValue(std::numeric_limits<T>::min());
A(++satValue == (std::numeric_limits<T>::min() + 1));
A(--satValue == (std::numeric_limits<T>::min()));
A(--satValue == (std::numeric_limits<T>::min())); // don't overflow here
A(--satValue == (std::numeric_limits<T>::min())); // don't overflow here
A(++satValue == (std::numeric_limits<T>::min() + 1)); // back at (max + 1)
A(++satValue == (std::numeric_limits<T>::min() + 2));
}
// Framework
//
template <typename T>
static void TestAll() {
// Assert that we don't accidently hit type's range limits in tests.
const T value = StartValue<T>();
A(std::numeric_limits<T>::min() + static_cast<T>(sNumOps) <= value);
A(std::numeric_limits<T>::max() - static_cast<T>(sNumOps) >= value);
TestPrefixIncr<T>();
TestPostfixIncr<T>();
TestAdd<T>();
TestPrefixDecr<T>();
TestPostfixDecr<T>();
TestSub<T>();
TestUpperBound<T>();
TestLowerBound<T>();
}
int main() {
TestAll<int8_t>();
TestAll<int16_t>();
TestAll<int32_t>();
TestAll<uint8_t>();
TestAll<uint16_t>();
TestAll<uint32_t>();
return 0;
}