1 | /* -*- C++ -*- |
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2 | * src/lemon/notifier.h - Part of LEMON, a generic C++ optimization library |
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3 | * |
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4 | * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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5 | * (Egervary Research Group on Combinatorial Optimization, EGRES). |
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6 | * |
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7 | * Permission to use, modify and distribute this software is granted |
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8 | * provided that this copyright notice appears in all copies. For |
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9 | * precise terms see the accompanying LICENSE file. |
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10 | * |
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11 | * This software is provided "AS IS" with no warranty of any kind, |
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12 | * express or implied, and with no claim as to its suitability for any |
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13 | * purpose. |
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14 | * |
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15 | */ |
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16 | |
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17 | #ifndef LEMON_ALTERATION_OBSERVER_REGISTRY_H |
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18 | #define LEMON_ALTERATION_OBSERVER_REGISTRY_H |
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19 | |
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20 | #include <vector> |
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21 | #include <algorithm> |
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22 | |
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23 | ///\ingroup graphmaps |
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24 | ///\file |
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25 | ///\brief Observer registry for graph alteration observers. |
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26 | |
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27 | namespace lemon { |
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28 | |
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29 | /// \addtogroup graphmaps |
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30 | /// @{ |
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31 | |
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32 | /// Registry class to register objects observes alterations in the graph. |
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33 | |
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34 | /// This class is a registry for the objects which observe the |
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35 | /// alterations in a container. The alteration observers can be attached |
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36 | /// to and detached from the registry. The observers have to inherit |
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37 | /// from the \ref AlterationNotifier::ObserverBase and override |
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38 | /// the virtual functions in that. |
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39 | /// |
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40 | /// The most important application of the alteration observing is the |
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41 | /// dynamic map implementation when the observers are observing the |
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42 | /// alterations in the graph. |
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43 | /// |
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44 | /// \param _Item The item type what the observers are observing, usually |
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45 | /// edge or node. |
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46 | /// |
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47 | /// \author Balazs Dezso |
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48 | |
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49 | template <typename _Item> |
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50 | class AlterationNotifier { |
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51 | public: |
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52 | typedef _Item Item; |
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53 | |
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54 | /// ObserverBase is the base class for the observers. |
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55 | |
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56 | /// ObserverBase is the abstract base class for the observers. |
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57 | /// It will be notified about an item was inserted into or |
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58 | /// erased from the graph. |
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59 | /// |
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60 | /// The observer interface contains some pure virtual functions |
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61 | /// to override. The add() and erase() functions are |
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62 | /// to notify the oberver when one item is added or |
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63 | /// erased. |
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64 | /// |
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65 | /// The build() and clear() members are to notify the observer |
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66 | /// about the container is built from an empty container or |
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67 | /// is cleared to an empty container. |
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68 | /// |
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69 | /// \author Balazs Dezso |
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70 | |
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71 | class ObserverBase { |
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72 | protected: |
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73 | typedef AlterationNotifier Registry; |
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74 | |
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75 | friend class AlterationNotifier; |
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76 | |
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77 | /// Default constructor. |
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78 | |
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79 | /// Default constructor for ObserverBase. |
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80 | /// |
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81 | ObserverBase() : registry(0) {} |
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82 | |
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83 | virtual ~ObserverBase() {} |
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84 | |
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85 | /// Attaches the observer into an AlterationNotifier. |
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86 | |
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87 | /// This member attaches the observer into an AlterationNotifier. |
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88 | /// |
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89 | void attach(AlterationNotifier& r) { |
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90 | registry = &r; |
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91 | registry->attach(*this); |
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92 | } |
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93 | |
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94 | /// Detaches the observer into an AlterationNotifier. |
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95 | |
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96 | /// This member detaches the observer from an AlterationNotifier. |
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97 | /// |
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98 | void detach() { |
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99 | if (registry) { |
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100 | registry->detach(*this); |
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101 | } |
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102 | } |
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103 | |
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104 | |
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105 | /// Gives back a pointer to the registry what the map attached into. |
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106 | |
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107 | /// This function gives back a pointer to the registry what the map |
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108 | /// attached into. |
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109 | /// |
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110 | Registry* getRegistry() const { return const_cast<Registry*>(registry); } |
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111 | |
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112 | /// Gives back true when the observer is attached into a registry. |
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113 | bool attached() const { return registry != 0; } |
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114 | |
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115 | private: |
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116 | |
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117 | ObserverBase(const ObserverBase& copy); |
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118 | ObserverBase& operator=(const ObserverBase& copy); |
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119 | |
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120 | protected: |
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121 | |
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122 | Registry* registry; |
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123 | int registry_index; |
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124 | |
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125 | public: |
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126 | |
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127 | /// \brief The member function to notificate the observer about an |
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128 | /// item is added to the container. |
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129 | /// |
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130 | /// The add() member function notificates the observer about an item |
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131 | /// is added to the container. It have to be overrided in the |
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132 | /// subclasses. |
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133 | |
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134 | virtual void add(const Item&) = 0; |
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135 | |
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136 | |
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137 | /// \brief The member function to notificate the observer about an |
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138 | /// item is erased from the container. |
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139 | /// |
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140 | /// The erase() member function notificates the observer about an |
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141 | /// item is erased from the container. It have to be overrided in |
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142 | /// the subclasses. |
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143 | |
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144 | virtual void erase(const Item&) = 0; |
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145 | |
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146 | /// \brief The member function to notificate the observer about the |
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147 | /// container is built. |
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148 | /// |
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149 | /// The build() member function notificates the observer about the |
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150 | /// container is built from an empty container. It have to be |
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151 | /// overrided in the subclasses. |
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152 | |
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153 | virtual void build() = 0; |
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154 | |
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155 | /// \brief The member function to notificate the observer about all |
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156 | /// items are erased from the container. |
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157 | /// |
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158 | /// The clear() member function notificates the observer about all |
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159 | /// items are erased from the container. It have to be overrided in |
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160 | /// the subclasses. |
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161 | |
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162 | virtual void clear() = 0; |
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163 | |
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164 | }; |
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165 | |
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166 | protected: |
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167 | |
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168 | |
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169 | typedef std::vector<ObserverBase*> Container; |
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170 | |
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171 | Container container; |
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172 | |
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173 | |
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174 | public: |
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175 | |
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176 | /// Default constructor. |
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177 | |
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178 | /// |
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179 | /// The default constructor of the AlterationNotifier. |
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180 | /// It creates an empty registry. |
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181 | AlterationNotifier() {} |
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182 | |
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183 | /// Copy Constructor of the AlterationNotifier. |
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184 | |
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185 | /// Copy constructor of the AlterationNotifier. |
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186 | /// It creates only an empty registry because the copiable |
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187 | /// registry's observers have to be registered still into that registry. |
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188 | AlterationNotifier(const AlterationNotifier&) {} |
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189 | |
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190 | /// Assign operator. |
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191 | |
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192 | /// Assign operator for the AlterationNotifier. |
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193 | /// It makes the notifier only empty because the copiable |
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194 | /// notifier's observers have to be registered still into that registry. |
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195 | AlterationNotifier& operator=(const AlterationNotifier&) { |
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196 | typename Container::iterator it; |
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197 | for (it = container.begin(); it != container.end(); ++it) { |
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198 | (*it)->registry = 0; |
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199 | } |
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200 | } |
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201 | |
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202 | /// Destructor. |
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203 | |
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204 | /// Destructor of the AlterationNotifier. |
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205 | /// |
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206 | ~AlterationNotifier() { |
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207 | typename Container::iterator it; |
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208 | for (it = container.begin(); it != container.end(); ++it) { |
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209 | (*it)->registry = 0; |
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210 | } |
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211 | } |
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212 | |
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213 | |
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214 | protected: |
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215 | |
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216 | void attach(ObserverBase& observer) { |
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217 | container.push_back(&observer); |
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218 | observer.registry = this; |
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219 | observer.registry_index = container.size()-1; |
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220 | } |
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221 | |
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222 | void detach(ObserverBase& base) { |
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223 | container.back()->registry_index = base.registry_index; |
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224 | container[base.registry_index] = container.back(); |
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225 | container.pop_back(); |
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226 | base.registry = 0; |
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227 | } |
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228 | |
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229 | public: |
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230 | |
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231 | /// Notifies all the registered observers about an Item added to the container. |
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232 | |
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233 | /// It notifies all the registered observers about an Item added to the container. |
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234 | /// |
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235 | void add(const Item& key) { |
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236 | typename Container::iterator it; |
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237 | for (it = container.begin(); it != container.end(); ++it) { |
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238 | (*it)->add(key); |
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239 | } |
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240 | } |
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241 | |
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242 | /// Notifies all the registered observers about an Item erased from the container. |
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243 | |
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244 | /// It notifies all the registered observers about an Item erased from the container. |
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245 | /// |
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246 | void erase(const Item& key) { |
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247 | typename Container::iterator it; |
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248 | for (it = container.begin(); it != container.end(); ++it) { |
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249 | (*it)->erase(key); |
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250 | } |
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251 | } |
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252 | |
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253 | |
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254 | /// Notifies all the registered observers about the container is built. |
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255 | |
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256 | /// Notifies all the registered observers about the container is built |
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257 | /// from an empty container. |
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258 | void build() { |
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259 | typename Container::iterator it; |
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260 | for (it = container.begin(); it != container.end(); ++it) { |
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261 | (*it)->build(); |
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262 | } |
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263 | } |
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264 | |
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265 | |
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266 | /// Notifies all the registered observers about all Items are erased. |
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267 | |
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268 | /// Notifies all the registered observers about all Items are erased |
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269 | /// from the container. |
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270 | void clear() { |
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271 | typename Container::iterator it; |
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272 | for (it = container.begin(); it != container.end(); ++it) { |
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273 | (*it)->clear(); |
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274 | } |
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275 | } |
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276 | }; |
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277 | |
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278 | |
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279 | /// \brief Class to extend a graph with the functionality of alteration |
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280 | /// observing. |
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281 | /// |
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282 | /// AlterableGraphExtender extends the _Base graphs functionality with |
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283 | /// the possibility of alteration observing. It defines two observer |
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284 | /// registrys for the nodes and mapes. |
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285 | /// |
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286 | /// \todo Document what "alteration observing" is. And probably find a |
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287 | /// better (shorter) name. |
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288 | /// |
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289 | /// \param _Base is the base class to extend. |
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290 | /// |
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291 | /// \pre _Base is conform to the BaseGraphComponent concept. |
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292 | /// |
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293 | /// \post AlterableGraphExtender<_Base> is conform to the |
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294 | /// AlterableGraphComponent concept. |
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295 | /// |
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296 | /// \author Balazs Dezso |
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297 | |
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298 | template <typename _Base> |
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299 | class AlterableGraphExtender : public _Base { |
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300 | public: |
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301 | |
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302 | typedef AlterableGraphExtender Graph; |
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303 | typedef _Base Parent; |
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304 | |
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305 | typedef typename Parent::Node Node; |
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306 | typedef typename Parent::Edge Edge; |
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307 | |
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308 | /// The edge observer registry. |
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309 | typedef AlterationNotifier<Edge> EdgeNotifier; |
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310 | /// The node observer registry. |
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311 | typedef AlterationNotifier<Node> NodeNotifier; |
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312 | |
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313 | |
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314 | protected: |
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315 | |
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316 | mutable EdgeNotifier edge_notifier; |
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317 | |
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318 | mutable NodeNotifier node_notifier; |
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319 | |
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320 | public: |
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321 | |
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322 | /// \brief Gives back the edge alteration notifier. |
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323 | /// |
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324 | /// Gives back the edge alteration notifier. |
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325 | EdgeNotifier& getNotifier(Edge) const { |
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326 | return edge_notifier; |
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327 | } |
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328 | |
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329 | /// \brief Gives back the node alteration notifier. |
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330 | /// |
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331 | /// Gives back the node alteration notifier. |
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332 | NodeNotifier& getNotifier(Node) const { |
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333 | return node_notifier; |
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334 | } |
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335 | |
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336 | ~AlterableGraphExtender() { |
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337 | node_notifier.clear(); |
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338 | edge_notifier.clear(); |
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339 | } |
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340 | |
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341 | }; |
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342 | |
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343 | /// \brief Class to extend an undirected graph with the functionality of |
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344 | /// alteration observing. |
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345 | /// |
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346 | /// \todo Document. |
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347 | /// |
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348 | /// \sa AlterableGraphExtender |
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349 | /// |
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350 | /// \bug This should be done some other way. Possibilities: template |
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351 | /// specialization (not very easy, if at all possible); some kind of |
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352 | /// enable_if boost technique? |
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353 | |
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354 | template <typename _Base> |
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355 | class AlterableUndirGraphExtender |
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356 | : public AlterableGraphExtender<_Base> { |
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357 | public: |
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358 | |
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359 | typedef AlterableUndirGraphExtender Graph; |
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360 | typedef AlterableGraphExtender<_Base> Parent; |
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361 | |
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362 | typedef typename Parent::UndirEdge UndirEdge; |
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363 | |
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364 | /// The edge observer registry. |
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365 | typedef AlterationNotifier<UndirEdge> UndirEdgeNotifier; |
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366 | |
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367 | protected: |
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368 | |
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369 | mutable UndirEdgeNotifier undir_edge_notifier; |
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370 | |
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371 | public: |
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372 | |
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373 | using Parent::getNotifier; |
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374 | UndirEdgeNotifier& getNotifier(UndirEdge) const { |
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375 | return undir_edge_notifier; |
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376 | } |
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377 | |
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378 | ~AlterableUndirGraphExtender() { |
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379 | undir_edge_notifier.clear(); |
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380 | } |
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381 | }; |
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382 | |
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383 | /// @} |
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384 | |
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385 | |
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386 | } |
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387 | |
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388 | #endif |
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