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/interface/atomic32.h" 12 13 #include <assert.h> 14 #include <windows.h> 15 16 #include "webrtc/common_types.h" 17 #include "webrtc/system_wrappers/interface/compile_assert.h" 18 19 namespace webrtc { 20 21 Atomic32::Atomic32(int32_t initial_value) 22 : value_(initial_value) { 23 COMPILE_ASSERT(sizeof(value_) == sizeof(LONG), 24 counter_variable_is_the_expected_size); 25 assert(Is32bitAligned()); 26 } 27 28 Atomic32::~Atomic32() { 29 } 30 31 int32_t Atomic32::operator++() { 32 return static_cast<int32_t>(InterlockedIncrement( 33 reinterpret_cast<volatile LONG*>(&value_))); 34 } 35 36 int32_t Atomic32::operator--() { 37 return static_cast<int32_t>(InterlockedDecrement( 38 reinterpret_cast<volatile LONG*>(&value_))); 39 } 40 41 int32_t Atomic32::operator+=(int32_t value) { 42 return InterlockedExchangeAdd(reinterpret_cast<volatile LONG*>(&value_), 43 value); 44 } 45 46 int32_t Atomic32::operator-=(int32_t value) { 47 return InterlockedExchangeAdd(reinterpret_cast<volatile LONG*>(&value_), 48 -value); 49 } 50 51 bool Atomic32::CompareExchange(int32_t new_value, int32_t compare_value) { 52 const LONG old_value = InterlockedCompareExchange( 53 reinterpret_cast<volatile LONG*>(&value_), 54 new_value, 55 compare_value); 56 57 // If the old value and the compare value is the same an exchange happened. 58 return (old_value == compare_value); 59 } 60 61 } // namespace webrtc 62