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/*
* Copyright (c) 2011 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.
*/
// Atomic system independant 32-bit signed integer.
// Linux implementation.
// Note: Requires gcc 4.1.2 or later.
#ifndef WEBRTC_SYSTEM_WRAPPERS_SOURCE_ATOMIC32_LINUX_H_
#define WEBRTC_SYSTEM_WRAPPERS_SOURCE_ATOMIC32_LINUX_H_
#include <inttypes.h>
#include <malloc.h>
#include "common_types.h"
namespace webrtc {
class Atomic32Impl
{
public:
inline Atomic32Impl(WebRtc_Word32 initialValue);
inline ~Atomic32Impl();
inline WebRtc_Word32 operator++();
inline WebRtc_Word32 operator--();
inline Atomic32Impl& operator=(const Atomic32Impl& rhs);
inline Atomic32Impl& operator=(WebRtc_Word32 rhs);
inline WebRtc_Word32 operator+=(WebRtc_Word32 rhs);
inline WebRtc_Word32 operator-=(WebRtc_Word32 rhs);
inline bool CompareExchange(WebRtc_Word32 newValue,
WebRtc_Word32 compareValue);
inline WebRtc_Word32 Value() const;
private:
void* _ptrMemory;
// Volatile ensures full memory barriers.
volatile WebRtc_Word32* _value;
};
// TODO (hellner) use aligned_malloc instead of doing it manually.
inline Atomic32Impl::Atomic32Impl(WebRtc_Word32 initialValue)
: _ptrMemory(NULL),
_value(NULL)
{ // Align the memory associated with _value on a 32-bit boundary. This is a
// requirement for the used Linux APIs to be atomic.
// Keep _ptrMemory to be able to reclaim memory.
_ptrMemory = malloc(sizeof(WebRtc_Word32)*2);
_value = (WebRtc_Word32*) (((uintptr_t)_ptrMemory+3)&(~0x3));
*_value = initialValue;
}
inline Atomic32Impl::~Atomic32Impl()
{
if(_ptrMemory != NULL)
{
free(_ptrMemory);
}
}
inline WebRtc_Word32 Atomic32Impl::operator++()
{
WebRtc_Word32 returnValue = __sync_fetch_and_add(_value,1);
returnValue++;
return returnValue;
}
inline WebRtc_Word32 Atomic32Impl::operator--()
{
WebRtc_Word32 returnValue = __sync_fetch_and_sub(_value,1);
returnValue--;
return returnValue;
}
inline Atomic32Impl& Atomic32Impl::operator=(const Atomic32Impl& rhs)
{
*_value = *rhs._value;
return *this;
}
inline Atomic32Impl& Atomic32Impl::operator=(WebRtc_Word32 rhs)
{
*_value = rhs;
return *this;
}
inline WebRtc_Word32 Atomic32Impl::operator+=(WebRtc_Word32 rhs)
{
WebRtc_Word32 returnValue = __sync_fetch_and_add(_value,rhs);
returnValue += rhs;
return returnValue;
}
inline WebRtc_Word32 Atomic32Impl::operator-=(WebRtc_Word32 rhs)
{
WebRtc_Word32 returnValue = __sync_fetch_and_sub(_value,rhs);
returnValue -= rhs;
return returnValue;
}
inline bool Atomic32Impl::CompareExchange(WebRtc_Word32 newValue,
WebRtc_Word32 compareValue)
{
return __sync_bool_compare_and_swap(_value,compareValue,newValue);
}
inline WebRtc_Word32 Atomic32Impl::Value() const
{
return *_value;
}
} // namespace webrtc
#endif // WEBRTC_SYSTEM_WRAPPERS_SOURCE_ATOMIC32_LINUX_H_
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