atomic_sequence_num.h revision 3345a6884c488ff3a535c2c9acdd33d74b37e311 
1// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_ATOMIC_SEQUENCE_NUM_H_
6#define BASE_ATOMIC_SEQUENCE_NUM_H_
7#pragma once
8
9#include "base/atomicops.h"
10#include "base/basictypes.h"
11
12namespace base {
13
14class AtomicSequenceNumber {
15 public:
16  AtomicSequenceNumber() : seq_(0) { }
17  explicit AtomicSequenceNumber(base::LinkerInitialized x) { /* seq_ is 0 */ }
18
19  int GetNext() {
20    return static_cast<int>(
21        base::subtle::NoBarrier_AtomicIncrement(&seq_, 1) - 1);
22  }
23
24 private:
25  base::subtle::Atomic32 seq_;
26  DISALLOW_COPY_AND_ASSIGN(AtomicSequenceNumber);
27};
28
29}  // namespace base
30
31#endif  // BASE_ATOMIC_SEQUENCE_NUM_H_
32