114 lines
3.2 KiB
C++
114 lines
3.2 KiB
C++
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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// Atomic system independant 32-bit signed integer.
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// Windows implementation.
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#ifndef WEBRTC_SYSTEM_WRAPPERS_SOURCE_ATOMIC32_WINDOWS_H_
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#define WEBRTC_SYSTEM_WRAPPERS_SOURCE_ATOMIC32_WINDOWS_H_
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#include <malloc.h>
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#include <windows.h>
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#include "common_types.h"
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namespace webrtc {
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class Atomic32Impl
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{
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public:
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inline Atomic32Impl(WebRtc_Word32 initialValue);
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inline ~Atomic32Impl();
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inline WebRtc_Word32 operator++();
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inline WebRtc_Word32 operator--();
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inline Atomic32Impl& operator=(const Atomic32Impl& rhs);
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inline Atomic32Impl& operator=(WebRtc_Word32 rhs);
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inline WebRtc_Word32 operator+=(WebRtc_Word32 rhs);
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inline WebRtc_Word32 operator-=(WebRtc_Word32 rhs);
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inline bool CompareExchange(WebRtc_Word32 newValue,
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WebRtc_Word32 compareValue);
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inline WebRtc_Word32 Value() const;
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private:
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void* _ptrMemory;
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// Volatile ensures full memory barriers.
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volatile LONG* _value;
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};
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// TODO (hellner) use aligned_malloc instead of doing it manually.
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inline Atomic32Impl::Atomic32Impl(WebRtc_Word32 initialValue)
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: _ptrMemory(NULL),
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_value(NULL)
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{ // Align the memory associated with _value on a 32-bit boundary. This is a
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// requirement for the used Windows APIs to be atomic.
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// Keep _ptrMemory to be able to reclaim memory.
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_ptrMemory = malloc(sizeof(WebRtc_Word32)*2);
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_value = reinterpret_cast<LONG*> (((uintptr_t)_ptrMemory+3)&(~0x3));
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*_value = initialValue;
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}
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inline Atomic32Impl::~Atomic32Impl()
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{
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if(_ptrMemory != NULL)
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{
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free(_ptrMemory);
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}
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}
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inline WebRtc_Word32 Atomic32Impl::operator++()
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{
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return (WebRtc_Word32)InterlockedIncrement(_value);
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}
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inline WebRtc_Word32 Atomic32Impl::operator--()
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{
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return (WebRtc_Word32)InterlockedDecrement(_value);
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}
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inline Atomic32Impl& Atomic32Impl::operator=(const Atomic32Impl& rhs)
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{
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*_value = *rhs._value;
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return *this;
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}
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inline Atomic32Impl& Atomic32Impl::operator=(WebRtc_Word32 rhs)
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{
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*_value = rhs;
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return *this;
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}
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inline WebRtc_Word32 Atomic32Impl::operator+=(WebRtc_Word32 rhs)
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{
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return InterlockedExchangeAdd(_value,rhs);
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}
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inline WebRtc_Word32 Atomic32Impl::operator-=(WebRtc_Word32 rhs)
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{
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return InterlockedExchangeAdd(_value,-rhs);
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}
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inline bool Atomic32Impl::CompareExchange(WebRtc_Word32 newValue,
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WebRtc_Word32 compareValue)
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{
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const LONG oldValue = InterlockedCompareExchange(_value,newValue,
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compareValue);
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// If the old value and the compare value is the same an exchange happened.
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return (oldValue == compareValue);
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}
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inline WebRtc_Word32 Atomic32Impl::Value() const
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{
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return *_value;
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}
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} // namespace webrtc
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#endif // WEBRTC_SYSTEM_WRAPPERS_SOURCE_ATOMIC32_WINDOWS_H_
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