gecko-dev/mfbt/Saturate.h

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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, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* Provides saturation arithmetics for scalar types. */
#ifndef mozilla_Saturate_h
#define mozilla_Saturate_h
Bug 1609996 - Reorder some includes affected by the previous patches. r=froydnj This was done by: This was done by applying: ``` diff --git a/python/mozbuild/mozbuild/code-analysis/mach_commands.py b/python/mozbuild/mozbuild/code-analysis/mach_commands.py index 789affde7bbf..fe33c4c7d4d1 100644 --- a/python/mozbuild/mozbuild/code-analysis/mach_commands.py +++ b/python/mozbuild/mozbuild/code-analysis/mach_commands.py @@ -2007,7 +2007,7 @@ class StaticAnalysis(MachCommandBase): from subprocess import Popen, PIPE, check_output, CalledProcessError diff_process = Popen(self._get_clang_format_diff_command(commit), stdout=PIPE) - args = [sys.executable, clang_format_diff, "-p1", "-binary=%s" % clang_format] + args = [sys.executable, clang_format_diff, "-p1", "-binary=%s" % clang_format, '-sort-includes'] if not output_file: args.append("-i") ``` Then running `./mach clang-format -c <commit-hash>` Then undoing that patch. Then running check_spidermonkey_style.py --fixup Then running `./mach clang-format` I had to fix four things: * I needed to move <utility> back down in GuardObjects.h because I was hitting obscure problems with our system include wrappers like this: 0:03.94 /usr/include/stdlib.h:550:14: error: exception specification in declaration does not match previous declaration 0:03.94 extern void *realloc (void *__ptr, size_t __size) 0:03.94 ^ 0:03.94 /home/emilio/src/moz/gecko-2/obj-debug/dist/include/malloc_decls.h:53:1: note: previous declaration is here 0:03.94 MALLOC_DECL(realloc, void*, void*, size_t) 0:03.94 ^ 0:03.94 /home/emilio/src/moz/gecko-2/obj-debug/dist/include/mozilla/mozalloc.h:22:32: note: expanded from macro 'MALLOC_DECL' 0:03.94 MOZ_MEMORY_API return_type name##_impl(__VA_ARGS__); 0:03.94 ^ 0:03.94 <scratch space>:178:1: note: expanded from here 0:03.94 realloc_impl 0:03.94 ^ 0:03.94 /home/emilio/src/moz/gecko-2/obj-debug/dist/include/mozmemory_wrap.h:142:41: note: expanded from macro 'realloc_impl' 0:03.94 #define realloc_impl mozmem_malloc_impl(realloc) Which I really didn't feel like digging into. * I had to restore the order of TrustOverrideUtils.h and related files in nss because the .inc files depend on TrustOverrideUtils.h being included earlier. * I had to add a missing include to RollingNumber.h * Also had to partially restore include order in JsepSessionImpl.cpp to avoid some -WError issues due to some static inline functions being defined in a header but not used in the rest of the compilation unit. Differential Revision: https://phabricator.services.mozilla.com/D60327 --HG-- extra : moz-landing-system : lando
2020-01-20 16:19:48 +00:00
#include <limits>
#include <stdint.h>
#include <type_traits>
#include <utility>
Bug 1609996 - Reorder some includes affected by the previous patches. r=froydnj This was done by: This was done by applying: ``` diff --git a/python/mozbuild/mozbuild/code-analysis/mach_commands.py b/python/mozbuild/mozbuild/code-analysis/mach_commands.py index 789affde7bbf..fe33c4c7d4d1 100644 --- a/python/mozbuild/mozbuild/code-analysis/mach_commands.py +++ b/python/mozbuild/mozbuild/code-analysis/mach_commands.py @@ -2007,7 +2007,7 @@ class StaticAnalysis(MachCommandBase): from subprocess import Popen, PIPE, check_output, CalledProcessError diff_process = Popen(self._get_clang_format_diff_command(commit), stdout=PIPE) - args = [sys.executable, clang_format_diff, "-p1", "-binary=%s" % clang_format] + args = [sys.executable, clang_format_diff, "-p1", "-binary=%s" % clang_format, '-sort-includes'] if not output_file: args.append("-i") ``` Then running `./mach clang-format -c <commit-hash>` Then undoing that patch. Then running check_spidermonkey_style.py --fixup Then running `./mach clang-format` I had to fix four things: * I needed to move <utility> back down in GuardObjects.h because I was hitting obscure problems with our system include wrappers like this: 0:03.94 /usr/include/stdlib.h:550:14: error: exception specification in declaration does not match previous declaration 0:03.94 extern void *realloc (void *__ptr, size_t __size) 0:03.94 ^ 0:03.94 /home/emilio/src/moz/gecko-2/obj-debug/dist/include/malloc_decls.h:53:1: note: previous declaration is here 0:03.94 MALLOC_DECL(realloc, void*, void*, size_t) 0:03.94 ^ 0:03.94 /home/emilio/src/moz/gecko-2/obj-debug/dist/include/mozilla/mozalloc.h:22:32: note: expanded from macro 'MALLOC_DECL' 0:03.94 MOZ_MEMORY_API return_type name##_impl(__VA_ARGS__); 0:03.94 ^ 0:03.94 <scratch space>:178:1: note: expanded from here 0:03.94 realloc_impl 0:03.94 ^ 0:03.94 /home/emilio/src/moz/gecko-2/obj-debug/dist/include/mozmemory_wrap.h:142:41: note: expanded from macro 'realloc_impl' 0:03.94 #define realloc_impl mozmem_malloc_impl(realloc) Which I really didn't feel like digging into. * I had to restore the order of TrustOverrideUtils.h and related files in nss because the .inc files depend on TrustOverrideUtils.h being included earlier. * I had to add a missing include to RollingNumber.h * Also had to partially restore include order in JsepSessionImpl.cpp to avoid some -WError issues due to some static inline functions being defined in a header but not used in the rest of the compilation unit. Differential Revision: https://phabricator.services.mozilla.com/D60327 --HG-- extra : moz-landing-system : lando
2020-01-20 16:19:48 +00:00
#include "mozilla/Attributes.h"
namespace mozilla {
namespace detail {
/**
* |SaturateOp<T>| wraps scalar values for saturation arithmetics. Usage:
*
* uint32_t value = 1;
*
* ++SaturateOp<uint32_t>(value); // value is 2
* --SaturateOp<uint32_t>(value); // value is 1
* --SaturateOp<uint32_t>(value); // value is 0
* --SaturateOp<uint32_t>(value); // value is still 0
*
* Please add new operators when required.
*
* |SaturateOp<T>| will saturate at the minimum and maximum values of
* type T. If you need other bounds, implement a clamped-type class and
* specialize the type traits accordingly.
*/
template <typename T>
class SaturateOp {
public:
explicit SaturateOp(T& aValue) : mValue(aValue) {
// We should actually check for |std::is_scalar<T>::value| to be
// true, but this type trait is not available everywhere. Relax
// this assertion if you want to use floating point values as well.
static_assert(std::is_integral_v<T>,
"Integral type required in instantiation");
}
// Add and subtract operators
T operator+(const T& aRhs) const { return T(mValue) += aRhs; }
T operator-(const T& aRhs) const { return T(mValue) -= aRhs; }
// Compound operators
const T& operator+=(const T& aRhs) const {
const T min = std::numeric_limits<T>::min();
const T max = std::numeric_limits<T>::max();
if (aRhs > static_cast<T>(0)) {
mValue = (max - aRhs) < mValue ? max : mValue + aRhs;
} else {
mValue = (min - aRhs) > mValue ? min : mValue + aRhs;
}
return mValue;
}
const T& operator-=(const T& aRhs) const {
const T min = std::numeric_limits<T>::min();
const T max = std::numeric_limits<T>::max();
if (aRhs > static_cast<T>(0)) {
mValue = (min + aRhs) > mValue ? min : mValue - aRhs;
} else {
mValue = (max + aRhs) < mValue ? max : mValue - aRhs;
}
return mValue;
}
// Increment and decrement operators
const T& operator++() const // prefix
{
return operator+=(static_cast<T>(1));
}
T operator++(int) const // postfix
{
const T value(mValue);
operator++();
return value;
}
const T& operator--() const // prefix
{
return operator-=(static_cast<T>(1));
}
T operator--(int) const // postfix
{
const T value(mValue);
operator--();
return value;
}
private:
SaturateOp(const SaturateOp<T>&) = delete;
SaturateOp(SaturateOp<T>&&) = delete;
SaturateOp& operator=(const SaturateOp<T>&) = delete;
SaturateOp& operator=(SaturateOp<T>&&) = delete;
T& mValue;
};
/**
* |Saturate<T>| is a value type for saturation arithmetics. It's
* built on top of |SaturateOp<T>|.
*/
template <typename T>
class Saturate {
public:
Saturate() = default;
MOZ_IMPLICIT Saturate(const Saturate<T>&) = default;
MOZ_IMPLICIT Saturate(Saturate<T>&& aValue) {
mValue = std::move(aValue.mValue);
}
explicit Saturate(const T& aValue) : mValue(aValue) {}
const T& value() const { return mValue; }
// Compare operators
bool operator==(const Saturate<T>& aRhs) const {
return mValue == aRhs.mValue;
}
bool operator!=(const Saturate<T>& aRhs) const { return !operator==(aRhs); }
bool operator==(const T& aRhs) const { return mValue == aRhs; }
bool operator!=(const T& aRhs) const { return !operator==(aRhs); }
// Assignment operators
Saturate<T>& operator=(const Saturate<T>&) = default;
Saturate<T>& operator=(Saturate<T>&& aRhs) {
mValue = std::move(aRhs.mValue);
return *this;
}
// Add and subtract operators
Saturate<T> operator+(const Saturate<T>& aRhs) const {
Saturate<T> lhs(mValue);
return lhs += aRhs.mValue;
}
Saturate<T> operator+(const T& aRhs) const {
Saturate<T> lhs(mValue);
return lhs += aRhs;
}
Saturate<T> operator-(const Saturate<T>& aRhs) const {
Saturate<T> lhs(mValue);
return lhs -= aRhs.mValue;
}
Saturate<T> operator-(const T& aRhs) const {
Saturate<T> lhs(mValue);
return lhs -= aRhs;
}
// Compound operators
Saturate<T>& operator+=(const Saturate<T>& aRhs) {
SaturateOp<T>(mValue) += aRhs.mValue;
return *this;
}
Saturate<T>& operator+=(const T& aRhs) {
SaturateOp<T>(mValue) += aRhs;
return *this;
}
Saturate<T>& operator-=(const Saturate<T>& aRhs) {
SaturateOp<T>(mValue) -= aRhs.mValue;
return *this;
}
Saturate<T>& operator-=(const T& aRhs) {
SaturateOp<T>(mValue) -= aRhs;
return *this;
}
// Increment and decrement operators
Saturate<T>& operator++() // prefix
{
++SaturateOp<T>(mValue);
return *this;
}
Saturate<T> operator++(int) // postfix
{
return Saturate<T>(SaturateOp<T>(mValue)++);
}
Saturate<T>& operator--() // prefix
{
--SaturateOp<T>(mValue);
return *this;
}
Saturate<T> operator--(int) // postfix
{
return Saturate<T>(SaturateOp<T>(mValue)--);
}
private:
T mValue;
};
} // namespace detail
typedef detail::Saturate<int8_t> SaturateInt8;
typedef detail::Saturate<int16_t> SaturateInt16;
typedef detail::Saturate<int32_t> SaturateInt32;
typedef detail::Saturate<uint8_t> SaturateUint8;
typedef detail::Saturate<uint16_t> SaturateUint16;
typedef detail::Saturate<uint32_t> SaturateUint32;
} // namespace mozilla
template <typename LhsT, typename RhsT>
bool operator==(LhsT aLhs, const mozilla::detail::Saturate<RhsT>& aRhs) {
return aRhs.operator==(static_cast<RhsT>(aLhs));
}
template <typename LhsT, typename RhsT>
bool operator!=(LhsT aLhs, const mozilla::detail::Saturate<RhsT>& aRhs) {
return !(aLhs == aRhs);
}
#endif // mozilla_Saturate_h