refcnt.hh revision 502
1/* 2 * Copyright (c) 2003 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 29#ifndef __REFCNT_HH__ 30#define __REFCNT_HH__ 31 32class RefCounted 33{ 34 private: 35 int count; 36 37 private: 38 RefCounted(const RefCounted &); 39 40 public: 41 RefCounted() : count(0) {} 42 virtual ~RefCounted() {} 43 44 void incref() { ++count; } 45 void decref() { if (--count <= 0) delete this; } 46}; 47 48template <class T> 49class RefCountingPtr 50{ 51 private: 52 T *data; 53 54 void copy(T *d) { 55 data = d; 56 if (data) 57 data->incref(); 58 } 59 void del() { 60 if (data) 61 data->decref(); 62 } 63 64 public: 65 RefCountingPtr() : data(NULL) {} 66 RefCountingPtr(T *data) { copy(data); } 67 RefCountingPtr(const RefCountingPtr &r) { copy(r.data); } 68 ~RefCountingPtr() { del(); } 69 70 T *operator->() { return data; } 71 T &operator*() { return *data; } 72 T *get() { return data; } 73 74 const T *operator->() const { return data; } 75 const T &operator*() const { return *data; } 76 const T *get() const { return data; } 77 78 RefCountingPtr &operator=(T *p) { 79 if (data != p) { 80 del(); 81 copy(p); 82 } 83 return *this; 84 } 85 86 RefCountingPtr &operator=(const RefCountingPtr &r) { 87 if (data != r.data) { 88 del(); 89 copy(r.data); 90 } 91 return *this; 92 } 93 94 bool operator!() const { return data == 0; } 95 operator bool() const { return data != 0; } 96}; 97 98template<class T> 99bool operator==(const RefCountingPtr<T> &l, const RefCountingPtr<T> &r) 100{ return l.get() == r.get(); } 101 102template<class T> 103bool operator==(const RefCountingPtr<T> &l, const T *r) 104{ return l.get() == r; } 105 106template<class T> 107bool operator==(const T &l, const RefCountingPtr<T> &r) 108{ return l == r.get(); } 109 110template<class T> 111bool operator!=(const RefCountingPtr<T> &l, const RefCountingPtr<T> &r) 112{ return l.get() != r.get(); } 113 114template<class T> 115bool operator!=(const RefCountingPtr<T> &l, const T *r) 116{ return l.get() != r; } 117 118template<class T> 119bool operator!=(const T &l, const RefCountingPtr<T> &r) 120{ return l != r.get(); } 121 122#endif // __REFCNT_HH__ 123