1 /* 2 * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "webrtc/system_wrappers/include/atomic32.h" 12 13 #include <assert.h> 14 #include <windows.h> 15 16 #include "webrtc/common_types.h" 17 18 namespace webrtc { 19 Atomic32(int32_t initial_value)20Atomic32::Atomic32(int32_t initial_value) 21 : value_(initial_value) { 22 static_assert(sizeof(value_) == sizeof(LONG), 23 "counter variable is the expected size"); 24 assert(Is32bitAligned()); 25 } 26 ~Atomic32()27Atomic32::~Atomic32() { 28 } 29 operator ++()30int32_t Atomic32::operator++() { 31 return static_cast<int32_t>(InterlockedIncrement( 32 reinterpret_cast<volatile LONG*>(&value_))); 33 } 34 operator --()35int32_t Atomic32::operator--() { 36 return static_cast<int32_t>(InterlockedDecrement( 37 reinterpret_cast<volatile LONG*>(&value_))); 38 } 39 operator +=(int32_t value)40int32_t Atomic32::operator+=(int32_t value) { 41 return InterlockedExchangeAdd(reinterpret_cast<volatile LONG*>(&value_), 42 value); 43 } 44 operator -=(int32_t value)45int32_t Atomic32::operator-=(int32_t value) { 46 return InterlockedExchangeAdd(reinterpret_cast<volatile LONG*>(&value_), 47 -value); 48 } 49 CompareExchange(int32_t new_value,int32_t compare_value)50bool Atomic32::CompareExchange(int32_t new_value, int32_t compare_value) { 51 const LONG old_value = InterlockedCompareExchange( 52 reinterpret_cast<volatile LONG*>(&value_), 53 new_value, 54 compare_value); 55 56 // If the old value and the compare value is the same an exchange happened. 57 return (old_value == compare_value); 58 } 59 60 } // namespace webrtc 61