scopedincrement.h
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1 /*
2  * Copyright (C) 2014 Tommi Maekitalo
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * As a special exception, you may use this file as part of a free
10  * software library without restriction. Specifically, if other files
11  * instantiate templates or use macros or inline functions from this
12  * file, or you compile this file and link it with other files to
13  * produce an executable, this file does not by itself cause the
14  * resulting executable to be covered by the GNU General Public
15  * License. This exception does not however invalidate any other
16  * reasons why the executable file might be covered by the GNU Library
17  * General Public License.
18  *
19  * This library is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
22  * Lesser General Public License for more details.
23  *
24  * You should have received a copy of the GNU Lesser General Public
25  * License along with this library; if not, write to the Free Software
26  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27  */
28 
29 #ifndef CXXTOOLS_SCOPEDINCREMENT_H
30 #define CXXTOOLS_SCOPEDINCREMENT_H
31 
32 #include <cxxtools/atomicity.h>
33 
34 namespace cxxtools
35 {
36 template <typename T>
38 {
39  T& _value;
40  T _count;
41 
42  public:
43  ScopedIncrement(T& value, T count = 1)
44  : _value(value),
45  _count(count)
46  {
47  _value += _count;
48  }
49 
51  {
52  _value -= _count;
53  }
54 };
55 
56 template <>
58 {
59  atomic_t& _value;
60  int _count;
61 
62  public:
63  ScopedIncrement(atomic_t& value, int count = 1)
64  : _value(value),
65  _count(count)
66  {
67  int c = _count;
68  for (; c > 0; --c)
69  atomicIncrement(_value);
70  for (; c < 0; ++c)
71  atomicDecrement(_value);
72  }
73 
75  {
76  int c = _count;
77  for (c = _count; c > 0; --c)
78  atomicDecrement(_value);
79  for (; c < 0; ++c)
80  atomicIncrement(_value);
81  }
82 };
83 
84 }
85 
86 #endif // CXXTOOLS_SCOPEDINCREMENT_H
87