[209] | 1 | /* -*- mode: C++; indent-tabs-mode: nil; -*- |
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[96] | 2 | * |
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[209] | 3 | * This file is a part of LEMON, a generic C++ optimization library. |
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[96] | 4 | * |
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[1270] | 5 | * Copyright (C) 2003-2013 |
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[96] | 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 | ///\ingroup concept |
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| 20 | ///\file |
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[832] | 21 | ///\brief The concept of paths |
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[96] | 22 | /// |
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| 23 | |
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[576] | 24 | #ifndef LEMON_CONCEPTS_PATH_H |
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| 25 | #define LEMON_CONCEPTS_PATH_H |
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[96] | 26 | |
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[220] | 27 | #include <lemon/core.h> |
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[96] | 28 | #include <lemon/concept_check.h> |
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| 29 | |
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| 30 | namespace lemon { |
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| 31 | namespace concepts { |
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| 32 | |
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| 33 | /// \addtogroup concept |
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| 34 | /// @{ |
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| 35 | |
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| 36 | /// \brief A skeleton structure for representing directed paths in |
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| 37 | /// a digraph. |
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| 38 | /// |
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| 39 | /// A skeleton structure for representing directed paths in a |
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[209] | 40 | /// digraph. |
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[832] | 41 | /// In a sense, a path can be treated as a list of arcs. |
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| 42 | /// LEMON path types just store this list. As a consequence, they cannot |
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| 43 | /// enumerate the nodes on the path directly and a zero length path |
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| 44 | /// cannot store its source node. |
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| 45 | /// |
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| 46 | /// The arcs of a path should be stored in the order of their directions, |
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| 47 | /// i.e. the target node of each arc should be the same as the source |
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| 48 | /// node of the next arc. This consistency could be checked using |
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| 49 | /// \ref checkPath(). |
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| 50 | /// The source and target nodes of a (consistent) path can be obtained |
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| 51 | /// using \ref pathSource() and \ref pathTarget(). |
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| 52 | /// |
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| 53 | /// A path can be constructed from another path of any type using the |
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| 54 | /// copy constructor or the assignment operator. |
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| 55 | /// |
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[606] | 56 | /// \tparam GR The digraph type in which the path is. |
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| 57 | template <typename GR> |
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[96] | 58 | class Path { |
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| 59 | public: |
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| 60 | |
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| 61 | /// Type of the underlying digraph. |
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[606] | 62 | typedef GR Digraph; |
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[96] | 63 | /// Arc type of the underlying digraph. |
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| 64 | typedef typename Digraph::Arc Arc; |
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| 65 | |
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| 66 | class ArcIt; |
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| 67 | |
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| 68 | /// \brief Default constructor |
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| 69 | Path() {} |
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| 70 | |
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[832] | 71 | /// \brief Template copy constructor |
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[96] | 72 | template <typename CPath> |
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| 73 | Path(const CPath& cpath) {} |
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| 74 | |
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[832] | 75 | /// \brief Template assigment operator |
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[96] | 76 | template <typename CPath> |
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[278] | 77 | Path& operator=(const CPath& cpath) { |
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[1257] | 78 | ::lemon::ignore_unused_variable_warning(cpath); |
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[278] | 79 | return *this; |
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| 80 | } |
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[96] | 81 | |
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[832] | 82 | /// Length of the path, i.e. the number of arcs on the path. |
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[96] | 83 | int length() const { return 0;} |
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| 84 | |
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| 85 | /// Returns whether the path is empty. |
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| 86 | bool empty() const { return true;} |
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| 87 | |
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| 88 | /// Resets the path to an empty path. |
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| 89 | void clear() {} |
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| 90 | |
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[832] | 91 | /// \brief LEMON style iterator for enumerating the arcs of a path. |
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[96] | 92 | /// |
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[832] | 93 | /// LEMON style iterator class for enumerating the arcs of a path. |
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[96] | 94 | class ArcIt { |
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| 95 | public: |
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[209] | 96 | /// Default constructor |
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| 97 | ArcIt() {} |
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| 98 | /// Invalid constructor |
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| 99 | ArcIt(Invalid) {} |
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[832] | 100 | /// Sets the iterator to the first arc of the given path |
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[209] | 101 | ArcIt(const Path &) {} |
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[96] | 102 | |
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[832] | 103 | /// Conversion to \c Arc |
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[209] | 104 | operator Arc() const { return INVALID; } |
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[96] | 105 | |
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[209] | 106 | /// Next arc |
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| 107 | ArcIt& operator++() {return *this;} |
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[96] | 108 | |
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[209] | 109 | /// Comparison operator |
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| 110 | bool operator==(const ArcIt&) const {return true;} |
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| 111 | /// Comparison operator |
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| 112 | bool operator!=(const ArcIt&) const {return true;} |
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[212] | 113 | /// Comparison operator |
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| 114 | bool operator<(const ArcIt&) const {return false;} |
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[96] | 115 | |
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| 116 | }; |
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| 117 | |
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| 118 | template <typename _Path> |
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| 119 | struct Constraints { |
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| 120 | void constraints() { |
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| 121 | Path<Digraph> pc; |
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| 122 | _Path p, pp(pc); |
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| 123 | int l = p.length(); |
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| 124 | int e = p.empty(); |
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| 125 | p.clear(); |
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| 126 | |
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| 127 | p = pc; |
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| 128 | |
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| 129 | typename _Path::ArcIt id, ii(INVALID), i(p); |
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| 130 | |
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| 131 | ++i; |
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| 132 | typename Digraph::Arc ed = i; |
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| 133 | |
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| 134 | e = (i == ii); |
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| 135 | e = (i != ii); |
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| 136 | e = (i < ii); |
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| 137 | |
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[1257] | 138 | ::lemon::ignore_unused_variable_warning(l); |
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| 139 | ::lemon::ignore_unused_variable_warning(pp); |
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| 140 | ::lemon::ignore_unused_variable_warning(e); |
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| 141 | ::lemon::ignore_unused_variable_warning(id); |
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| 142 | ::lemon::ignore_unused_variable_warning(ii); |
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| 143 | ::lemon::ignore_unused_variable_warning(ed); |
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[96] | 144 | } |
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| 145 | }; |
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| 146 | |
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| 147 | }; |
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| 148 | |
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| 149 | namespace _path_bits { |
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[209] | 150 | |
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[96] | 151 | template <typename _Digraph, typename _Path, typename RevPathTag = void> |
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| 152 | struct PathDumperConstraints { |
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| 153 | void constraints() { |
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| 154 | int l = p.length(); |
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| 155 | int e = p.empty(); |
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| 156 | |
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| 157 | typename _Path::ArcIt id, i(p); |
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| 158 | |
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| 159 | ++i; |
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| 160 | typename _Digraph::Arc ed = i; |
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| 161 | |
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| 162 | e = (i == INVALID); |
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| 163 | e = (i != INVALID); |
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| 164 | |
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[1257] | 165 | ::lemon::ignore_unused_variable_warning(l); |
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| 166 | ::lemon::ignore_unused_variable_warning(e); |
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| 167 | ::lemon::ignore_unused_variable_warning(id); |
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| 168 | ::lemon::ignore_unused_variable_warning(ed); |
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[96] | 169 | } |
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| 170 | _Path& p; |
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[1125] | 171 | PathDumperConstraints() {} |
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[96] | 172 | }; |
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| 173 | |
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| 174 | template <typename _Digraph, typename _Path> |
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| 175 | struct PathDumperConstraints< |
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[209] | 176 | _Digraph, _Path, |
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[96] | 177 | typename enable_if<typename _Path::RevPathTag, void>::type |
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| 178 | > { |
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| 179 | void constraints() { |
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| 180 | int l = p.length(); |
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| 181 | int e = p.empty(); |
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| 182 | |
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| 183 | typename _Path::RevArcIt id, i(p); |
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| 184 | |
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| 185 | ++i; |
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| 186 | typename _Digraph::Arc ed = i; |
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| 187 | |
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| 188 | e = (i == INVALID); |
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| 189 | e = (i != INVALID); |
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| 190 | |
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[1257] | 191 | ::lemon::ignore_unused_variable_warning(l); |
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| 192 | ::lemon::ignore_unused_variable_warning(e); |
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| 193 | ::lemon::ignore_unused_variable_warning(id); |
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| 194 | ::lemon::ignore_unused_variable_warning(ed); |
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[96] | 195 | } |
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| 196 | _Path& p; |
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[1125] | 197 | PathDumperConstraints() {} |
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[96] | 198 | }; |
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[209] | 199 | |
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[96] | 200 | } |
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| 201 | |
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| 202 | |
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| 203 | /// \brief A skeleton structure for path dumpers. |
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| 204 | /// |
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| 205 | /// A skeleton structure for path dumpers. The path dumpers are |
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[832] | 206 | /// the generalization of the paths, they can enumerate the arcs |
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| 207 | /// of the path either in forward or in backward order. |
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| 208 | /// These classes are typically not used directly, they are rather |
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| 209 | /// used to be assigned to a real path type. |
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[96] | 210 | /// |
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| 211 | /// The main purpose of this concept is that the shortest path |
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[832] | 212 | /// algorithms can enumerate the arcs easily in reverse order. |
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| 213 | /// In LEMON, such algorithms give back a (reverse) path dumper that |
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| 214 | /// can be assigned to a real path. The dumpers can be implemented as |
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[96] | 215 | /// an adaptor class to the predecessor map. |
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[606] | 216 | /// |
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| 217 | /// \tparam GR The digraph type in which the path is. |
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| 218 | template <typename GR> |
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[96] | 219 | class PathDumper { |
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| 220 | public: |
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| 221 | |
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| 222 | /// Type of the underlying digraph. |
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[606] | 223 | typedef GR Digraph; |
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[96] | 224 | /// Arc type of the underlying digraph. |
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| 225 | typedef typename Digraph::Arc Arc; |
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| 226 | |
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[832] | 227 | /// Length of the path, i.e. the number of arcs on the path. |
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[96] | 228 | int length() const { return 0;} |
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| 229 | |
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| 230 | /// Returns whether the path is empty. |
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| 231 | bool empty() const { return true;} |
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| 232 | |
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| 233 | /// \brief Forward or reverse dumping |
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| 234 | /// |
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[832] | 235 | /// If this tag is defined to be \c True, then reverse dumping |
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| 236 | /// is provided in the path dumper. In this case, \c RevArcIt |
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| 237 | /// iterator should be implemented instead of \c ArcIt iterator. |
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[96] | 238 | typedef False RevPathTag; |
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| 239 | |
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[832] | 240 | /// \brief LEMON style iterator for enumerating the arcs of a path. |
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[96] | 241 | /// |
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[832] | 242 | /// LEMON style iterator class for enumerating the arcs of a path. |
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[96] | 243 | class ArcIt { |
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| 244 | public: |
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[209] | 245 | /// Default constructor |
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| 246 | ArcIt() {} |
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| 247 | /// Invalid constructor |
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| 248 | ArcIt(Invalid) {} |
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[832] | 249 | /// Sets the iterator to the first arc of the given path |
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[209] | 250 | ArcIt(const PathDumper&) {} |
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[96] | 251 | |
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[832] | 252 | /// Conversion to \c Arc |
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[209] | 253 | operator Arc() const { return INVALID; } |
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[96] | 254 | |
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[209] | 255 | /// Next arc |
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| 256 | ArcIt& operator++() {return *this;} |
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[96] | 257 | |
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[209] | 258 | /// Comparison operator |
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| 259 | bool operator==(const ArcIt&) const {return true;} |
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| 260 | /// Comparison operator |
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| 261 | bool operator!=(const ArcIt&) const {return true;} |
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[212] | 262 | /// Comparison operator |
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| 263 | bool operator<(const ArcIt&) const {return false;} |
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[96] | 264 | |
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| 265 | }; |
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| 266 | |
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[832] | 267 | /// \brief LEMON style iterator for enumerating the arcs of a path |
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| 268 | /// in reverse direction. |
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[96] | 269 | /// |
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[832] | 270 | /// LEMON style iterator class for enumerating the arcs of a path |
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| 271 | /// in reverse direction. |
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[96] | 272 | class RevArcIt { |
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| 273 | public: |
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[209] | 274 | /// Default constructor |
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| 275 | RevArcIt() {} |
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| 276 | /// Invalid constructor |
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| 277 | RevArcIt(Invalid) {} |
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[832] | 278 | /// Sets the iterator to the last arc of the given path |
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[209] | 279 | RevArcIt(const PathDumper &) {} |
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[96] | 280 | |
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[832] | 281 | /// Conversion to \c Arc |
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[209] | 282 | operator Arc() const { return INVALID; } |
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[96] | 283 | |
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[209] | 284 | /// Next arc |
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| 285 | RevArcIt& operator++() {return *this;} |
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[96] | 286 | |
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[209] | 287 | /// Comparison operator |
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| 288 | bool operator==(const RevArcIt&) const {return true;} |
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| 289 | /// Comparison operator |
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| 290 | bool operator!=(const RevArcIt&) const {return true;} |
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[212] | 291 | /// Comparison operator |
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| 292 | bool operator<(const RevArcIt&) const {return false;} |
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[96] | 293 | |
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| 294 | }; |
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| 295 | |
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| 296 | template <typename _Path> |
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| 297 | struct Constraints { |
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| 298 | void constraints() { |
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| 299 | function_requires<_path_bits:: |
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| 300 | PathDumperConstraints<Digraph, _Path> >(); |
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| 301 | } |
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| 302 | }; |
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| 303 | |
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| 304 | }; |
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| 305 | |
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| 306 | |
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| 307 | ///@} |
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| 308 | } |
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| 309 | |
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| 310 | } // namespace lemon |
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| 311 | |
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[576] | 312 | #endif |
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