1 ////////////////////////////////////////////////////////////////////////
2 //
3 // Copyright (C) 2012-2021 The Octave Project Developers
4 //
5 // See the file COPYRIGHT.md in the top-level directory of this
6 // distribution or <https://octave.org/copyright/>.
7 //
8 // This file is part of Octave.
9 //
10 // Octave is free software: you can redistribute it and/or modify it
11 // under the terms of the GNU General Public License as published by
12 // the Free Software Foundation, either version 3 of the License, or
13 // (at your option) any later version.
14 //
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16 // WITHOUT ANY WARRANTY; without even the implied warranty of
17 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18 // GNU General Public License for more details.
19 //
20 // You should have received a copy of the GNU General Public License
21 // along with Octave; see the file COPYING.  If not, see
22 // <https://www.gnu.org/licenses/>.
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24 ////////////////////////////////////////////////////////////////////////
25 
26 #if ! defined (octave_oct_refcount_h)
27 #define octave_oct_refcount_h 1
28 
29 #include "octave-config.h"
30 
31 #include <atomic>
32 
33 namespace octave
34 {
35   // Encapsulates a reference counter.
36 
37   template <typename T>
38   class refcount
39   {
40   public:
41 
42     typedef T count_type;
43 
refcount(count_type initial_count)44     refcount (count_type initial_count)
45       : m_count (initial_count)
46     { }
47 
48     refcount (const refcount&) = delete;
49 
50     refcount& operator = (const refcount&) = delete;
51 
52     ~refcount (void) = default;
53 
54     // Increment/Decrement.  int is postfix.
55     count_type operator++ (void)
56     {
57       return ++m_count;
58     }
59 
60     count_type operator++ (int)
61     {
62       return m_count++;
63     }
64 
65     count_type operator-- (void)
66     {
67       return --m_count;
68     }
69 
70     count_type operator-- (int)
71     {
72       return m_count--;
73     }
74 
value(void)75     count_type value (void) const
76     {
77       return m_count.load ();
78     }
79 
count_type(void)80     operator count_type (void) const
81     {
82       return value ();
83     }
84 
85   private:
86 
87     std::atomic<T> m_count;
88   };
89 }
90 
91 #endif
92