refcnt.hh revision 8220 
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 __BASE_REFCNT_HH__
32#define __BASE_REFCNT_HH__
33
34class RefCounted
35{
36  private:
37    mutable int count;
38
39  private:
40    // Don't allow a default copy constructor or copy operator on
41    // these objects because the default operation will copy the
42    // reference count as well and we certainly don't want that.
43    RefCounted(const RefCounted &);
44    RefCounted &operator=(const RefCounted &);
45
46  public:
47    RefCounted() : count(0) {}
48    virtual ~RefCounted() {}
49
50    void incref() { ++count; }
51    void decref() { if (--count <= 0) delete this; }
52};
53
54template <class T>
55class RefCountingPtr
56{
57  protected:
58    T *data;
59
60    void copy(T *d)
61    {
62        data = d;
63        if (data)
64            data->incref();
65    }
66    void del()
67    {
68        if (data)
69            data->decref();
70    }
71    void set(T *d)
72    {
73        if (data == d)
74            return;
75
76        del();
77        copy(d);
78    }
79
80
81  public:
82    RefCountingPtr() : data(0) {}
83    RefCountingPtr(T *data) { copy(data); }
84    RefCountingPtr(const RefCountingPtr &r) { copy(r.data); }
85    ~RefCountingPtr() { del(); }
86
87    T *operator->() const { return data; }
88    T &operator*() const { return *data; }
89    T *get() const { return data; }
90
91    const RefCountingPtr &operator=(T *p) { set(p); return *this; }
92    const RefCountingPtr &operator=(const RefCountingPtr &r)
93    { return operator=(r.data); }
94
95    bool operator!() const { return data == 0; }
96    operator bool() const { return data != 0; }
97};
98
99template<class T>
100inline bool operator==(const RefCountingPtr<T> &l, const RefCountingPtr<T> &r)
101{ return l.get() == r.get(); }
102
103template<class T>
104inline bool operator==(const RefCountingPtr<T> &l, const T *r)
105{ return l.get() == r; }
106
107template<class T>
108inline bool operator==(const T *l, const RefCountingPtr<T> &r)
109{ return l == r.get(); }
110
111template<class T>
112inline bool operator!=(const RefCountingPtr<T> &l, const RefCountingPtr<T> &r)
113{ return l.get() != r.get(); }
114
115template<class T>
116inline bool operator!=(const RefCountingPtr<T> &l, const T *r)
117{ return l.get() != r; }
118
119template<class T>
120inline bool operator!=(const T *l, const RefCountingPtr<T> &r)
121{ return l != r.get(); }
122
123#endif // __BASE_REFCNT_HH__
124