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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
#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;
}
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