| /* |
| * 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: uses full memory barriers. |
| // Note: assumes 32-bit (or higher) system |
| #ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ATOMIC32_H_ |
| #define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ATOMIC32_H_ |
| |
| #include <cstddef> |
| |
| #include "common_types.h" |
| #include "constructor_magic.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(WebRtc_Word32 initialValue = 0); |
| ~Atomic32(); |
| |
| // Prefix operator! |
| WebRtc_Word32 operator++(); |
| WebRtc_Word32 operator--(); |
| |
| WebRtc_Word32 operator+=(WebRtc_Word32 value); |
| WebRtc_Word32 operator-=(WebRtc_Word32 value); |
| |
| // Sets the value atomically to newValue if the value equals compare value. |
| // The function returns true if the exchange happened. |
| bool CompareExchange(WebRtc_Word32 newValue, WebRtc_Word32 compareValue); |
| WebRtc_Word32 Value() const; |
| |
| 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; |
| } |
| |
| DISALLOW_COPY_AND_ASSIGN(Atomic32); |
| |
| WebRtc_Word32 _value; |
| }; |
| } // namespace webrtc |
| |
| #endif // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_ATOMIC32_H_ |