[959] | 1 | /* -*- C++ -*- |
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| 2 | * src/lemon/concept/path.h - Part of LEMON, a generic C++ optimization library |
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| 3 | * |
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| 4 | * Copyright (C) 2004 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport |
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| 5 | * (Egervary Combinatorial Optimization Research Group, 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 | ///\ingroup concept |
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| 18 | ///\file |
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| 19 | ///\brief Classes for representing paths in graphs. |
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| 20 | |
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| 21 | #ifndef LEMON_CONCEPT_PATH_H |
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| 22 | #define LEMON_CONCEPT_PATH_H |
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| 23 | |
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| 24 | #include <lemon/invalid.h> |
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| 25 | |
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| 26 | namespace lemon { |
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| 27 | namespace concept { |
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| 28 | /// \addtogroup concept |
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| 29 | /// @{ |
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| 30 | |
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| 31 | |
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[967] | 32 | //! \brief A skeleton structure for representing directed paths in a graph. |
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[959] | 33 | //! |
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| 34 | //! A skeleton structure for representing directed paths in a graph. |
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| 35 | //! \param GR The graph type in which the path is. |
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| 36 | //! |
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| 37 | //! In a sense, the path can be treated as a graph, for is has \c NodeIt |
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| 38 | //! and \c EdgeIt with the same usage. These types converts to the \c Node |
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| 39 | //! and \c Edge of the original graph. |
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| 40 | template<typename GR> |
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| 41 | class Path { |
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| 42 | public: |
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| 43 | |
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| 44 | /// Type of the underlying graph. |
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| 45 | typedef /*typename*/ GR Graph; |
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| 46 | /// Edge type of the underlying graph. |
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| 47 | typedef typename Graph::Edge GraphEdge; |
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| 48 | /// Node type of the underlying graph. |
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| 49 | typedef typename Graph::Node GraphNode; |
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| 50 | class NodeIt; |
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| 51 | class EdgeIt; |
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| 52 | |
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| 53 | /// \param _G The graph in which the path is. |
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| 54 | /// |
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| 55 | Path(const Graph &_G) {} |
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| 56 | |
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| 57 | /// Length of the path. |
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| 58 | size_t length() const {return 0;} |
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| 59 | /// Returns whether the path is empty. |
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| 60 | bool empty() const { return true;} |
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| 61 | |
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| 62 | /// Resets the path to an empty path. |
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| 63 | void clear() {} |
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| 64 | |
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| 65 | /// \brief Starting point of the path. |
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| 66 | /// |
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| 67 | /// Starting point of the path. |
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| 68 | /// Returns INVALID if the path is empty. |
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[986] | 69 | GraphNode/*It*/ target() const {return INVALID;} |
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[959] | 70 | /// \brief End point of the path. |
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| 71 | /// |
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| 72 | /// End point of the path. |
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| 73 | /// Returns INVALID if the path is empty. |
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[986] | 74 | GraphNode/*It*/ source() const {return INVALID;} |
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[959] | 75 | |
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| 76 | /// \brief First NodeIt/EdgeIt. |
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| 77 | /// |
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| 78 | /// Initializes node or edge iterator to point to the first |
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| 79 | /// node or edge. |
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| 80 | template<typename It> |
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| 81 | It& first(It &i) const { return i=It(*this); } |
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| 82 | |
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[986] | 83 | /// \brief The target of an edge. |
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[959] | 84 | /// |
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[986] | 85 | /// Returns node iterator pointing to the target node of the |
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[959] | 86 | /// given edge iterator. |
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[986] | 87 | NodeIt target(const EdgeIt& e) const {return INVALID;} |
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[959] | 88 | |
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[986] | 89 | /// \brief The source of an edge. |
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[959] | 90 | /// |
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[986] | 91 | /// Returns node iterator pointing to the source node of the |
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[959] | 92 | /// given edge iterator. |
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[986] | 93 | NodeIt source(const EdgeIt& e) const {return INVALID;} |
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[959] | 94 | |
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| 95 | |
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| 96 | /* Iterator classes */ |
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| 97 | |
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| 98 | /** |
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| 99 | * \brief Iterator class to iterate on the edges of the paths |
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| 100 | * |
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| 101 | * \ingroup concept |
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| 102 | * This class is used to iterate on the edges of the paths |
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| 103 | * |
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| 104 | * Of course it converts to Graph::Edge |
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| 105 | * |
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| 106 | */ |
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| 107 | class EdgeIt { |
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| 108 | public: |
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| 109 | /// Default constructor |
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| 110 | EdgeIt() {} |
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| 111 | /// Invalid constructor |
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| 112 | EdgeIt(Invalid) {} |
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| 113 | /// Constructor with starting point |
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| 114 | EdgeIt(const Path &_p) {} |
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| 115 | |
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| 116 | operator GraphEdge () const {} |
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| 117 | |
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| 118 | /// Next edge |
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| 119 | EdgeIt& operator++() {return *this;} |
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| 120 | |
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| 121 | /// Comparison operator |
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| 122 | bool operator==(const EdgeIt& e) const {return true;} |
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| 123 | /// Comparison operator |
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| 124 | bool operator!=(const EdgeIt& e) const {return true;} |
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| 125 | // /// Comparison operator |
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| 126 | // /// \todo It is not clear what is the "natural" ordering. |
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| 127 | // bool operator<(const EdgeIt& e) const {} |
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| 128 | |
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| 129 | }; |
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| 130 | |
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| 131 | /** |
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| 132 | * \brief Iterator class to iterate on the nodes of the paths |
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| 133 | * |
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| 134 | * \ingroup concept |
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| 135 | * This class is used to iterate on the nodes of the paths |
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| 136 | * |
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| 137 | * Of course it converts to Graph::Node. |
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| 138 | * |
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| 139 | */ |
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| 140 | class NodeIt { |
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| 141 | public: |
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| 142 | /// Default constructor |
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| 143 | NodeIt() {} |
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| 144 | /// Invalid constructor |
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| 145 | NodeIt(Invalid) {} |
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| 146 | /// Constructor with starting point |
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| 147 | NodeIt(const Path &_p) {} |
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| 148 | |
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| 149 | ///Conversion to Graph::Node |
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| 150 | operator const GraphNode& () const {} |
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| 151 | /// Next node |
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| 152 | NodeIt& operator++() {return *this;} |
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| 153 | |
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| 154 | /// Comparison operator |
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| 155 | bool operator==(const NodeIt& e) const {return true;} |
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| 156 | /// Comparison operator |
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| 157 | bool operator!=(const NodeIt& e) const {return true;} |
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| 158 | // /// Comparison operator |
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| 159 | // /// \todo It is not clear what is the "natural" ordering. |
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| 160 | // bool operator<(const NodeIt& e) const {} |
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| 161 | |
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| 162 | }; |
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| 163 | |
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| 164 | friend class Builder; |
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| 165 | |
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| 166 | /** |
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| 167 | * \brief Class to build paths |
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| 168 | * |
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| 169 | * \ingroup concept |
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| 170 | * This class is used to fill a path with edges. |
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| 171 | * |
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| 172 | * You can push new edges to the front and to the back of the path in |
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| 173 | * arbitrary order then you should commit these changes to the graph. |
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| 174 | * |
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| 175 | * While the builder is active (after the first modifying |
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| 176 | * operation and until the call of \ref commit()) |
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| 177 | * the underlining Path is in a |
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| 178 | * "transitional" state (operations on it have undefined result). |
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| 179 | */ |
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| 180 | class Builder { |
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| 181 | public: |
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| 182 | |
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| 183 | Path &P; |
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| 184 | |
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| 185 | ///\param _P the path you want to fill in. |
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| 186 | /// |
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| 187 | Builder(Path &_P) : P(_P) {} |
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| 188 | |
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| 189 | /// Sets the starting node of the path. |
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| 190 | |
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| 191 | /// Sets the starting node of the path. Edge added to the path |
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| 192 | /// afterwards have to be incident to this node. |
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| 193 | /// You \em must start building an empry path with this functions. |
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| 194 | /// (And you \em must \em not use it later). |
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| 195 | /// \sa pushFront() |
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| 196 | /// \sa pushBack() |
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| 197 | void setStartNode(const GraphNode &) {} |
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| 198 | |
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| 199 | ///Push a new edge to the front of the path |
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| 200 | |
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| 201 | ///Push a new edge to the front of the path. |
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| 202 | ///If the path is empty, you \em must call \ref setStartNode() before |
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| 203 | ///the first use of \ref pushFront(). |
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| 204 | void pushFront(const GraphEdge& e) {} |
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| 205 | |
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| 206 | ///Push a new edge to the back of the path |
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| 207 | |
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| 208 | ///Push a new edge to the back of the path. |
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| 209 | ///If the path is empty, you \em must call \ref setStartNode() before |
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| 210 | ///the first use of \ref pushBack(). |
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| 211 | void pushBack(const GraphEdge& e) {} |
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| 212 | |
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| 213 | ///Commit the changes to the path. |
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| 214 | void commit() {} |
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| 215 | |
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| 216 | ///Reserve (front) storage for the builder in advance. |
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| 217 | |
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| 218 | ///If you know an reasonable upper bound of the number of the edges |
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| 219 | ///to add to the front of the path, |
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| 220 | ///using this function you may speed up the building. |
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| 221 | void reserveFront(size_t r) {} |
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| 222 | ///Reserve (back) storage for the builder in advance. |
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| 223 | |
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| 224 | ///If you know an reasonable upper bound of the number of the edges |
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| 225 | ///to add to the back of the path, |
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| 226 | ///using this function you may speed up the building. |
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| 227 | void reserveBack(size_t r) {} |
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| 228 | }; |
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| 229 | }; |
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| 230 | |
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| 231 | ///@} |
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| 232 | } |
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| 233 | |
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| 234 | } // namespace lemon |
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| 235 | |
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| 236 | #endif // LEMON_CONCEPT_PATH_H |
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