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/*
* Copyright (c) 2012 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 independent 32-bit integer. Unless you know what you're
// doing, use locks instead! :-)
//
// Note: assumes 32-bit (or higher) system
#ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ATOMIC32_H_
#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ATOMIC32_H_
#include <stddef.h>
#include "webrtc/base/constructormagic.h"
#include "webrtc/common_types.h"
namespace webrtc {
// 32 bit atomic variable. Note that this class relies on the compiler to
// align the 32 bit value correctly (on a 32 bit boundary), so as long as you're
// not doing things like reinterpret_cast over some custom allocated memory
// without being careful with alignment, you should be fine.
class Atomic32 {
public:
Atomic32(int32_t initial_value = 0);
~Atomic32();
// Prefix operator!
int32_t operator++();
int32_t operator--();
int32_t operator+=(int32_t value);
int32_t operator-=(int32_t value);
// Sets the value atomically to new_value if the value equals compare value.
// The function returns true if the exchange happened.
bool CompareExchange(int32_t new_value, int32_t compare_value);
int32_t Value() {
return *this += 0;
}
private:
// Disable the + and - operator since it's unclear what these operations
// should do.
Atomic32 operator+(const Atomic32& other);
Atomic32 operator-(const Atomic32& other);
// Checks if |_value| is 32bit aligned.
inline bool Is32bitAligned() const {
return (reinterpret_cast<ptrdiff_t>(&value_) & 3) == 0;
}
RTC_DISALLOW_COPY_AND_ASSIGN(Atomic32);
int32_t value_;
};
} // namespace webrtc
#endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ATOMIC32_H_
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