[1977] | 1 | /* -*- C++ -*- |
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| 2 | * |
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| 3 | * This file is a part of LEMON, a generic C++ optimization library |
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| 4 | * |
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| 5 | * Copyright (C) 2003-2006 |
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| 6 | * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 7 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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| 8 | * |
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| 9 | * Permission to use, modify and distribute this software is granted |
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| 10 | * provided that this copyright notice appears in all copies. For |
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| 11 | * precise terms see the accompanying LICENSE file. |
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| 12 | * |
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| 13 | * This software is provided "AS IS" with no warranty of any kind, |
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| 14 | * express or implied, and with no claim as to its suitability for any |
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| 15 | * purpose. |
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| 16 | * |
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| 17 | */ |
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| 18 | |
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| 19 | #ifndef LEMON_REFPTR_H |
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| 20 | #define LEMON_REFPTR_H |
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| 21 | |
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| 22 | ///\ingroup misc |
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| 23 | ///\file |
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| 24 | ///\brief A reference counted pointer implementation. |
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| 25 | /// |
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| 26 | ///\todo Undocumented |
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| 27 | |
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| 28 | |
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| 29 | namespace lemon { |
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| 30 | |
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| 31 | |
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| 32 | ///Reference counted pointer |
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| 33 | |
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| 34 | ///This is a simple implementation of a reference counted pointer. |
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| 35 | /// |
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| 36 | ///\warning Current implementation is far from being thread-safe. |
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| 37 | template<class T> |
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| 38 | class RefPtr |
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| 39 | { |
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| 40 | mutable RefPtr *prev, *next; |
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| 41 | T *ref; |
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| 42 | |
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| 43 | void lock() {} |
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| 44 | void unlock() {} |
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| 45 | |
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| 46 | void attach(RefPtr &r) |
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| 47 | { |
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[2151] | 48 | if(r.ref) { |
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| 49 | prev=&r; next=r.next; ref=r.ref; |
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| 50 | r.next=this; |
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| 51 | } |
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[1977] | 52 | } |
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| 53 | void attach(const T *p) |
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| 54 | { |
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| 55 | prev=0; next=0; ref=p; |
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| 56 | } |
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| 57 | void release() |
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| 58 | { |
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| 59 | if(ref) { |
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| 60 | bool fr=true; |
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| 61 | if(prev) { fr=false; prev->next=next; } |
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| 62 | if(next) { fr=false; next->prev=prev; } |
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| 63 | if(fr) delete ref; |
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| 64 | ref=0; |
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| 65 | } |
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| 66 | } |
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| 67 | |
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| 68 | public: |
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| 69 | ///\e |
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| 70 | RefPtr() : ref(0) {} |
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| 71 | |
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| 72 | ///\e |
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| 73 | RefPtr(const RefPtr &r) { |
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| 74 | lock(); |
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| 75 | attach(const_cast<RefPtr&>(r)); |
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| 76 | unlock(); |
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| 77 | } |
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| 78 | |
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| 79 | ///\e |
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| 80 | RefPtr(T *p) : prev(0), next(0), ref(p) {} |
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| 81 | |
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| 82 | ///\e |
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| 83 | ~RefPtr() { |
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| 84 | lock(); |
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| 85 | release(); |
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| 86 | unlock(); |
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| 87 | } |
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| 88 | |
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| 89 | ///\e |
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| 90 | const RefPtr &operator=(const RefPtr &r) { |
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| 91 | if(ref!=r.ref) { |
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| 92 | lock(); |
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| 93 | release(); attach(const_cast<RefPtr&>(r)); |
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| 94 | unlock(); |
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| 95 | } |
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| 96 | return *this; |
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| 97 | } |
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| 98 | |
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| 99 | ///\e |
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| 100 | const RefPtr &operator=(const T* &p) { |
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| 101 | if(ref!=p) { lock(); release(); attach(p); unlock(); } |
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| 102 | return *this; |
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| 103 | } |
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| 104 | |
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| 105 | ///\e |
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| 106 | void swap(RefPtr &r) { |
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| 107 | RefPtr *p; |
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| 108 | T *tp; |
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| 109 | lock(); |
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| 110 | p=prev; prev=r.prev; r.prev=p; |
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| 111 | p=next; next=r.next; r.next=p; |
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| 112 | tp=ref; ref=r.ref; r.ref=tp; |
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| 113 | unlock(); |
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| 114 | } |
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| 115 | |
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| 116 | ///\e |
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| 117 | void clear() { lock(); release(); unlock(); } |
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| 118 | |
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| 119 | ///\e |
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| 120 | T * operator->() { return ref; } |
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| 121 | ///\e |
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| 122 | const T * operator->() const { return ref; } |
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| 123 | ///\e |
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| 124 | operator T *() { return ref; } |
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| 125 | ///\e |
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| 126 | operator const T *() const { return ref; } |
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| 127 | |
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| 128 | ///\e |
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| 129 | bool operator<(const RefPtr &r) const { return this->ref < r.ref; } |
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| 130 | ///\e |
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| 131 | bool operator<=(const RefPtr &r) const { return this->ref <= r.ref; } |
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| 132 | ///\e |
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| 133 | bool operator==(const RefPtr &r) const { return this->ref == r.ref; } |
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| 134 | ///\e |
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| 135 | bool operator>=(const RefPtr &r) const { return this->ref >= r.ref; } |
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| 136 | ///\e |
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| 137 | bool operator>(const RefPtr &r) const { return this->ref > r.ref; } |
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| 138 | ///\e |
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| 139 | bool operator!=(const RefPtr &r) const { return this->ref != r.ref; } |
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| 140 | |
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| 141 | ///\e |
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| 142 | operator bool() const { return ref; } |
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| 143 | |
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[2151] | 144 | ///\e |
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| 145 | const RefPtr &borrow(const T* &p) { |
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| 146 | lock(); |
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| 147 | if(ref==p) { |
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| 148 | if(prev) prev->next=next; |
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| 149 | if(next) next->prev=prev; |
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| 150 | } |
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| 151 | else release(); |
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| 152 | ref=p; |
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| 153 | next=prev=this; |
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| 154 | unlock(); |
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| 155 | return *this; |
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| 156 | } |
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| 157 | |
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| 158 | ///\e |
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| 159 | const RefPtr &borrow() { |
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| 160 | lock(); |
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| 161 | if(prev) prev->next=next; |
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| 162 | if(next) next->prev=prev; |
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| 163 | next=prev=this; |
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| 164 | unlock(); |
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| 165 | return *this; |
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| 166 | } |
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| 167 | |
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[1977] | 168 | }; //END OF CLASS REFPTR |
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| 169 | |
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| 170 | } //END OF NAMESPACE LEMON |
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| 171 | |
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| 172 | #endif |
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