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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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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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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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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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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