1 /* 2 * Copyright 2011 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 #ifndef WEBRTC_BASE_ATOMICOPS_H_ 12 #define WEBRTC_BASE_ATOMICOPS_H_ 13 14 #if defined(WEBRTC_WIN) 15 // Include winsock2.h before including <windows.h> to maintain consistency with 16 // win32.h. We can't include win32.h directly here since it pulls in 17 // headers such as basictypes.h which causes problems in Chromium where webrtc 18 // exists as two separate projects, webrtc and libjingle. 19 #include <winsock2.h> 20 #include <windows.h> 21 #endif // defined(WEBRTC_WIN) 22 23 namespace rtc { 24 class AtomicOps { 25 public: 26 #if defined(WEBRTC_WIN) 27 // Assumes sizeof(int) == sizeof(LONG), which it is on Win32 and Win64. Increment(volatile int * i)28 static int Increment(volatile int* i) { 29 return ::InterlockedIncrement(reinterpret_cast<volatile LONG*>(i)); 30 } Decrement(volatile int * i)31 static int Decrement(volatile int* i) { 32 return ::InterlockedDecrement(reinterpret_cast<volatile LONG*>(i)); 33 } AcquireLoad(volatile const int * i)34 static int AcquireLoad(volatile const int* i) { 35 return *i; 36 } ReleaseStore(volatile int * i,int value)37 static void ReleaseStore(volatile int* i, int value) { 38 *i = value; 39 } CompareAndSwap(volatile int * i,int old_value,int new_value)40 static int CompareAndSwap(volatile int* i, int old_value, int new_value) { 41 return ::InterlockedCompareExchange(reinterpret_cast<volatile LONG*>(i), 42 new_value, 43 old_value); 44 } 45 // Pointer variants. 46 template <typename T> AcquireLoadPtr(T * volatile * ptr)47 static T* AcquireLoadPtr(T* volatile* ptr) { 48 return *ptr; 49 } 50 template <typename T> CompareAndSwapPtr(T * volatile * ptr,T * old_value,T * new_value)51 static T* CompareAndSwapPtr(T* volatile* ptr, T* old_value, T* new_value) { 52 return static_cast<T*>(::InterlockedCompareExchangePointer( 53 reinterpret_cast<PVOID volatile*>(ptr), new_value, old_value)); 54 } 55 #else 56 static int Increment(volatile int* i) { 57 return __sync_add_and_fetch(i, 1); 58 } 59 static int Decrement(volatile int* i) { 60 return __sync_sub_and_fetch(i, 1); 61 } 62 static int AcquireLoad(volatile const int* i) { 63 return __atomic_load_n(i, __ATOMIC_ACQUIRE); 64 } 65 static void ReleaseStore(volatile int* i, int value) { 66 __atomic_store_n(i, value, __ATOMIC_RELEASE); 67 } 68 static int CompareAndSwap(volatile int* i, int old_value, int new_value) { 69 return __sync_val_compare_and_swap(i, old_value, new_value); 70 } 71 // Pointer variants. 72 template <typename T> 73 static T* AcquireLoadPtr(T* volatile* ptr) { 74 return __atomic_load_n(ptr, __ATOMIC_ACQUIRE); 75 } 76 template <typename T> 77 static T* CompareAndSwapPtr(T* volatile* ptr, T* old_value, T* new_value) { 78 return __sync_val_compare_and_swap(ptr, old_value, new_value); 79 } 80 #endif 81 }; 82 83 84 85 } 86 87 #endif // WEBRTC_BASE_ATOMICOPS_H_ 88