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