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
23namespace rtc {
24class AtomicOps {
25 public:
26#if defined(WEBRTC_WIN)
27  // Assumes sizeof(int) == sizeof(LONG), which it is on Win32 and Win64.
28  static int Increment(volatile int* i) {
29    return ::InterlockedIncrement(reinterpret_cast<volatile LONG*>(i));
30  }
31  static int Decrement(volatile int* i) {
32    return ::InterlockedDecrement(reinterpret_cast<volatile LONG*>(i));
33  }
34  static int AcquireLoad(volatile const int* i) {
35    return *i;
36  }
37  static void ReleaseStore(volatile int* i, int value) {
38    *i = value;
39  }
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>
47  static T* AcquireLoadPtr(T* volatile* ptr) {
48    return *ptr;
49  }
50  template <typename T>
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