67 lines
2.0 KiB
C
67 lines
2.0 KiB
C
|
/*
|
||
|
|
* 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_INCLUDE_ATOMIC32_H_
|
||
|
|
#define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_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_INCLUDE_ATOMIC32_H_
|