refcnt.hh revision 2665:a124942bacb8 
1/*
2 * Copyright (c) 2002-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Nathan Binkert
29 */
30
31#ifndef __REFCNT_HH__
32#define __REFCNT_HH__
33
34#include <stddef.h> //For the NULL macro definition
35
36class RefCounted
37{
38  private:
39    int count;
40
41  private:
42    RefCounted(const RefCounted &);
43
44  public:
45    RefCounted() : count(0) {}
46    virtual ~RefCounted() {}
47
48    void incref() { ++count; }
49    void decref() { if (--count <= 0) delete this; }
50};
51
52template <class T>
53class RefCountingPtr
54{
55  protected:
56    T *data;
57
58    void copy(T *d)
59    {
60        data = d;
61        if (data)
62            data->incref();
63    }
64    void del()
65    {
66        if (data)
67            data->decref();
68    }
69    void set(T *d)
70    {
71        if (data == d)
72            return;
73
74        del();
75        copy(d);
76    }
77
78
79  public:
80    RefCountingPtr() : data(NULL) {}
81    RefCountingPtr(T *data) { copy(data); }
82    RefCountingPtr(const RefCountingPtr &r) { copy(r.data); }
83    ~RefCountingPtr() { del(); }
84
85    T *operator->() { return data; }
86    T &operator*() { return *data; }
87    T *get() { return data; }
88
89    const T *operator->() const { return data; }
90    const T &operator*() const { return *data; }
91    const T *get() const { return data; }
92
93    RefCountingPtr &operator=(T *p) { set(p); return *this; }
94    RefCountingPtr &operator=(const RefCountingPtr &r)
95    { return operator=(r.data); }
96
97    bool operator!() const { return data == 0; }
98    operator bool() const { return data != 0; }
99};
100
101template<class T>
102bool operator==(const RefCountingPtr<T> &l, const RefCountingPtr<T> &r)
103{ return l.get() == r.get(); }
104
105template<class T>
106bool operator==(const RefCountingPtr<T> &l, const T *r)
107{ return l.get() == r; }
108
109template<class T>
110bool operator==(const T &l, const RefCountingPtr<T> &r)
111{ return l == r.get(); }
112
113template<class T>
114bool operator!=(const RefCountingPtr<T> &l, const RefCountingPtr<T> &r)
115{ return l.get() != r.get(); }
116
117template<class T>
118bool operator!=(const RefCountingPtr<T> &l, const T *r)
119{ return l.get() != r; }
120
121template<class T>
122bool operator!=(const T &l, const RefCountingPtr<T> &r)
123{ return l != r.get(); }
124
125#endif // __REFCNT_HH__
126