lemon/lgf_reader.h
author Alpar Juttner <alpar@cs.elte.hu>
Mon, 30 Mar 2009 16:46:37 +0100
changeset 561 6e0525ec5355
parent 517 2b6d5d22bb23
child 584 33c6b6e755cd
child 598 a3402913cffe
permissions -rw-r--r--
Accept negative values as unbounded capacity in dimacs readers (#243)
and some doc improvements.
     1 /* -*- mode: C++; indent-tabs-mode: nil; -*-
     2  *
     3  * This file is a part of LEMON, a generic C++ optimization library.
     4  *
     5  * Copyright (C) 2003-2009
     6  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
     7  * (Egervary Research Group on Combinatorial Optimization, EGRES).
     8  *
     9  * Permission to use, modify and distribute this software is granted
    10  * provided that this copyright notice appears in all copies. For
    11  * precise terms see the accompanying LICENSE file.
    12  *
    13  * This software is provided "AS IS" with no warranty of any kind,
    14  * express or implied, and with no claim as to its suitability for any
    15  * purpose.
    16  *
    17  */
    18 
    19 ///\ingroup lemon_io
    20 ///\file
    21 ///\brief \ref lgf-format "LEMON Graph Format" reader.
    22 
    23 
    24 #ifndef LEMON_LGF_READER_H
    25 #define LEMON_LGF_READER_H
    26 
    27 #include <iostream>
    28 #include <fstream>
    29 #include <sstream>
    30 
    31 #include <set>
    32 #include <map>
    33 
    34 #include <lemon/core.h>
    35 
    36 #include <lemon/lgf_writer.h>
    37 
    38 #include <lemon/concept_check.h>
    39 #include <lemon/concepts/maps.h>
    40 
    41 namespace lemon {
    42 
    43   namespace _reader_bits {
    44 
    45     template <typename Value>
    46     struct DefaultConverter {
    47       Value operator()(const std::string& str) {
    48         std::istringstream is(str);
    49         Value value;
    50         if (!(is >> value)) {
    51           throw FormatError("Cannot read token");
    52         }
    53 
    54         char c;
    55         if (is >> std::ws >> c) {
    56           throw FormatError("Remaining characters in token");
    57         }
    58         return value;
    59       }
    60     };
    61 
    62     template <>
    63     struct DefaultConverter<std::string> {
    64       std::string operator()(const std::string& str) {
    65         return str;
    66       }
    67     };
    68 
    69     template <typename _Item>
    70     class MapStorageBase {
    71     public:
    72       typedef _Item Item;
    73 
    74     public:
    75       MapStorageBase() {}
    76       virtual ~MapStorageBase() {}
    77 
    78       virtual void set(const Item& item, const std::string& value) = 0;
    79 
    80     };
    81 
    82     template <typename _Item, typename _Map,
    83               typename _Converter = DefaultConverter<typename _Map::Value> >
    84     class MapStorage : public MapStorageBase<_Item> {
    85     public:
    86       typedef _Map Map;
    87       typedef _Converter Converter;
    88       typedef _Item Item;
    89 
    90     private:
    91       Map& _map;
    92       Converter _converter;
    93 
    94     public:
    95       MapStorage(Map& map, const Converter& converter = Converter())
    96         : _map(map), _converter(converter) {}
    97       virtual ~MapStorage() {}
    98 
    99       virtual void set(const Item& item ,const std::string& value) {
   100         _map.set(item, _converter(value));
   101       }
   102     };
   103 
   104     template <typename _Graph, bool _dir, typename _Map,
   105               typename _Converter = DefaultConverter<typename _Map::Value> >
   106     class GraphArcMapStorage : public MapStorageBase<typename _Graph::Edge> {
   107     public:
   108       typedef _Map Map;
   109       typedef _Converter Converter;
   110       typedef _Graph Graph;
   111       typedef typename Graph::Edge Item;
   112       static const bool dir = _dir;
   113 
   114     private:
   115       const Graph& _graph;
   116       Map& _map;
   117       Converter _converter;
   118 
   119     public:
   120       GraphArcMapStorage(const Graph& graph, Map& map,
   121                          const Converter& converter = Converter())
   122         : _graph(graph), _map(map), _converter(converter) {}
   123       virtual ~GraphArcMapStorage() {}
   124 
   125       virtual void set(const Item& item ,const std::string& value) {
   126         _map.set(_graph.direct(item, dir), _converter(value));
   127       }
   128     };
   129 
   130     class ValueStorageBase {
   131     public:
   132       ValueStorageBase() {}
   133       virtual ~ValueStorageBase() {}
   134 
   135       virtual void set(const std::string&) = 0;
   136     };
   137 
   138     template <typename _Value, typename _Converter = DefaultConverter<_Value> >
   139     class ValueStorage : public ValueStorageBase {
   140     public:
   141       typedef _Value Value;
   142       typedef _Converter Converter;
   143 
   144     private:
   145       Value& _value;
   146       Converter _converter;
   147 
   148     public:
   149       ValueStorage(Value& value, const Converter& converter = Converter())
   150         : _value(value), _converter(converter) {}
   151 
   152       virtual void set(const std::string& value) {
   153         _value = _converter(value);
   154       }
   155     };
   156 
   157     template <typename Value>
   158     struct MapLookUpConverter {
   159       const std::map<std::string, Value>& _map;
   160 
   161       MapLookUpConverter(const std::map<std::string, Value>& map)
   162         : _map(map) {}
   163 
   164       Value operator()(const std::string& str) {
   165         typename std::map<std::string, Value>::const_iterator it =
   166           _map.find(str);
   167         if (it == _map.end()) {
   168           std::ostringstream msg;
   169           msg << "Item not found: " << str;
   170           throw FormatError(msg.str());
   171         }
   172         return it->second;
   173       }
   174     };
   175 
   176     template <typename Graph>
   177     struct GraphArcLookUpConverter {
   178       const Graph& _graph;
   179       const std::map<std::string, typename Graph::Edge>& _map;
   180 
   181       GraphArcLookUpConverter(const Graph& graph,
   182                               const std::map<std::string,
   183                                              typename Graph::Edge>& map)
   184         : _graph(graph), _map(map) {}
   185 
   186       typename Graph::Arc operator()(const std::string& str) {
   187         if (str.empty() || (str[0] != '+' && str[0] != '-')) {
   188           throw FormatError("Item must start with '+' or '-'");
   189         }
   190         typename std::map<std::string, typename Graph::Edge>
   191           ::const_iterator it = _map.find(str.substr(1));
   192         if (it == _map.end()) {
   193           throw FormatError("Item not found");
   194         }
   195         return _graph.direct(it->second, str[0] == '+');
   196       }
   197     };
   198 
   199     inline bool isWhiteSpace(char c) {
   200       return c == ' ' || c == '\t' || c == '\v' ||
   201         c == '\n' || c == '\r' || c == '\f';
   202     }
   203 
   204     inline bool isOct(char c) {
   205       return '0' <= c && c <='7';
   206     }
   207 
   208     inline int valueOct(char c) {
   209       LEMON_ASSERT(isOct(c), "The character is not octal.");
   210       return c - '0';
   211     }
   212 
   213     inline bool isHex(char c) {
   214       return ('0' <= c && c <= '9') ||
   215         ('a' <= c && c <= 'z') ||
   216         ('A' <= c && c <= 'Z');
   217     }
   218 
   219     inline int valueHex(char c) {
   220       LEMON_ASSERT(isHex(c), "The character is not hexadecimal.");
   221       if ('0' <= c && c <= '9') return c - '0';
   222       if ('a' <= c && c <= 'z') return c - 'a' + 10;
   223       return c - 'A' + 10;
   224     }
   225 
   226     inline bool isIdentifierFirstChar(char c) {
   227       return ('a' <= c && c <= 'z') ||
   228         ('A' <= c && c <= 'Z') || c == '_';
   229     }
   230 
   231     inline bool isIdentifierChar(char c) {
   232       return isIdentifierFirstChar(c) ||
   233         ('0' <= c && c <= '9');
   234     }
   235 
   236     inline char readEscape(std::istream& is) {
   237       char c;
   238       if (!is.get(c))
   239         throw FormatError("Escape format error");
   240 
   241       switch (c) {
   242       case '\\':
   243         return '\\';
   244       case '\"':
   245         return '\"';
   246       case '\'':
   247         return '\'';
   248       case '\?':
   249         return '\?';
   250       case 'a':
   251         return '\a';
   252       case 'b':
   253         return '\b';
   254       case 'f':
   255         return '\f';
   256       case 'n':
   257         return '\n';
   258       case 'r':
   259         return '\r';
   260       case 't':
   261         return '\t';
   262       case 'v':
   263         return '\v';
   264       case 'x':
   265         {
   266           int code;
   267           if (!is.get(c) || !isHex(c))
   268             throw FormatError("Escape format error");
   269           else if (code = valueHex(c), !is.get(c) || !isHex(c)) is.putback(c);
   270           else code = code * 16 + valueHex(c);
   271           return code;
   272         }
   273       default:
   274         {
   275           int code;
   276           if (!isOct(c))
   277             throw FormatError("Escape format error");
   278           else if (code = valueOct(c), !is.get(c) || !isOct(c))
   279             is.putback(c);
   280           else if (code = code * 8 + valueOct(c), !is.get(c) || !isOct(c))
   281             is.putback(c);
   282           else code = code * 8 + valueOct(c);
   283           return code;
   284         }
   285       }
   286     }
   287 
   288     inline std::istream& readToken(std::istream& is, std::string& str) {
   289       std::ostringstream os;
   290 
   291       char c;
   292       is >> std::ws;
   293 
   294       if (!is.get(c))
   295         return is;
   296 
   297       if (c == '\"') {
   298         while (is.get(c) && c != '\"') {
   299           if (c == '\\')
   300             c = readEscape(is);
   301           os << c;
   302         }
   303         if (!is)
   304           throw FormatError("Quoted format error");
   305       } else {
   306         is.putback(c);
   307         while (is.get(c) && !isWhiteSpace(c)) {
   308           if (c == '\\')
   309             c = readEscape(is);
   310           os << c;
   311         }
   312         if (!is) {
   313           is.clear();
   314         } else {
   315           is.putback(c);
   316         }
   317       }
   318       str = os.str();
   319       return is;
   320     }
   321 
   322     class Section {
   323     public:
   324       virtual ~Section() {}
   325       virtual void process(std::istream& is, int& line_num) = 0;
   326     };
   327 
   328     template <typename Functor>
   329     class LineSection : public Section {
   330     private:
   331 
   332       Functor _functor;
   333 
   334     public:
   335 
   336       LineSection(const Functor& functor) : _functor(functor) {}
   337       virtual ~LineSection() {}
   338 
   339       virtual void process(std::istream& is, int& line_num) {
   340         char c;
   341         std::string line;
   342         while (is.get(c) && c != '@') {
   343           if (c == '\n') {
   344             ++line_num;
   345           } else if (c == '#') {
   346             getline(is, line);
   347             ++line_num;
   348           } else if (!isWhiteSpace(c)) {
   349             is.putback(c);
   350             getline(is, line);
   351             _functor(line);
   352             ++line_num;
   353           }
   354         }
   355         if (is) is.putback(c);
   356         else if (is.eof()) is.clear();
   357       }
   358     };
   359 
   360     template <typename Functor>
   361     class StreamSection : public Section {
   362     private:
   363 
   364       Functor _functor;
   365 
   366     public:
   367 
   368       StreamSection(const Functor& functor) : _functor(functor) {}
   369       virtual ~StreamSection() {}
   370 
   371       virtual void process(std::istream& is, int& line_num) {
   372         _functor(is, line_num);
   373         char c;
   374         std::string line;
   375         while (is.get(c) && c != '@') {
   376           if (c == '\n') {
   377             ++line_num;
   378           } else if (!isWhiteSpace(c)) {
   379             getline(is, line);
   380             ++line_num;
   381           }
   382         }
   383         if (is) is.putback(c);
   384         else if (is.eof()) is.clear();
   385       }
   386     };
   387 
   388   }
   389 
   390   template <typename Digraph>
   391   class DigraphReader;
   392 
   393   template <typename Digraph>
   394   DigraphReader<Digraph> digraphReader(Digraph& digraph, 
   395                                        std::istream& is = std::cin);
   396   template <typename Digraph>
   397   DigraphReader<Digraph> digraphReader(Digraph& digraph, const std::string& fn);
   398   template <typename Digraph>
   399   DigraphReader<Digraph> digraphReader(Digraph& digraph, const char *fn);
   400 
   401   /// \ingroup lemon_io
   402   ///
   403   /// \brief \ref lgf-format "LGF" reader for directed graphs
   404   ///
   405   /// This utility reads an \ref lgf-format "LGF" file.
   406   ///
   407   /// The reading method does a batch processing. The user creates a
   408   /// reader object, then various reading rules can be added to the
   409   /// reader, and eventually the reading is executed with the \c run()
   410   /// member function. A map reading rule can be added to the reader
   411   /// with the \c nodeMap() or \c arcMap() members. An optional
   412   /// converter parameter can also be added as a standard functor
   413   /// converting from \c std::string to the value type of the map. If it
   414   /// is set, it will determine how the tokens in the file should be
   415   /// converted to the value type of the map. If the functor is not set,
   416   /// then a default conversion will be used. One map can be read into
   417   /// multiple map objects at the same time. The \c attribute(), \c
   418   /// node() and \c arc() functions are used to add attribute reading
   419   /// rules.
   420   ///
   421   ///\code
   422   /// DigraphReader<Digraph>(digraph, std::cin).
   423   ///   nodeMap("coordinates", coord_map).
   424   ///   arcMap("capacity", cap_map).
   425   ///   node("source", src).
   426   ///   node("target", trg).
   427   ///   attribute("caption", caption).
   428   ///   run();
   429   ///\endcode
   430   ///
   431   /// By default the reader uses the first section in the file of the
   432   /// proper type. If a section has an optional name, then it can be
   433   /// selected for reading by giving an optional name parameter to the
   434   /// \c nodes(), \c arcs() or \c attributes() functions.
   435   ///
   436   /// The \c useNodes() and \c useArcs() functions are used to tell the reader
   437   /// that the nodes or arcs should not be constructed (added to the
   438   /// graph) during the reading, but instead the label map of the items
   439   /// are given as a parameter of these functions. An
   440   /// application of these functions is multipass reading, which is
   441   /// important if two \c \@arcs sections must be read from the
   442   /// file. In this case the first phase would read the node set and one
   443   /// of the arc sets, while the second phase would read the second arc
   444   /// set into an \e ArcSet class (\c SmartArcSet or \c ListArcSet).
   445   /// The previously read label node map should be passed to the \c
   446   /// useNodes() functions. Another application of multipass reading when
   447   /// paths are given as a node map or an arc map.
   448   /// It is impossible to read this in
   449   /// a single pass, because the arcs are not constructed when the node
   450   /// maps are read.
   451   template <typename GR>
   452   class DigraphReader {
   453   public:
   454 
   455     typedef GR Digraph;
   456 
   457   private:
   458 
   459     TEMPLATE_DIGRAPH_TYPEDEFS(Digraph);
   460 
   461     std::istream* _is;
   462     bool local_is;
   463     std::string _filename;
   464 
   465     Digraph& _digraph;
   466 
   467     std::string _nodes_caption;
   468     std::string _arcs_caption;
   469     std::string _attributes_caption;
   470 
   471     typedef std::map<std::string, Node> NodeIndex;
   472     NodeIndex _node_index;
   473     typedef std::map<std::string, Arc> ArcIndex;
   474     ArcIndex _arc_index;
   475 
   476     typedef std::vector<std::pair<std::string,
   477       _reader_bits::MapStorageBase<Node>*> > NodeMaps;
   478     NodeMaps _node_maps;
   479 
   480     typedef std::vector<std::pair<std::string,
   481       _reader_bits::MapStorageBase<Arc>*> >ArcMaps;
   482     ArcMaps _arc_maps;
   483 
   484     typedef std::multimap<std::string, _reader_bits::ValueStorageBase*>
   485       Attributes;
   486     Attributes _attributes;
   487 
   488     bool _use_nodes;
   489     bool _use_arcs;
   490 
   491     bool _skip_nodes;
   492     bool _skip_arcs;
   493 
   494     int line_num;
   495     std::istringstream line;
   496 
   497   public:
   498 
   499     /// \brief Constructor
   500     ///
   501     /// Construct a directed graph reader, which reads from the given
   502     /// input stream.
   503     DigraphReader(Digraph& digraph, std::istream& is = std::cin)
   504       : _is(&is), local_is(false), _digraph(digraph),
   505         _use_nodes(false), _use_arcs(false),
   506         _skip_nodes(false), _skip_arcs(false) {}
   507 
   508     /// \brief Constructor
   509     ///
   510     /// Construct a directed graph reader, which reads from the given
   511     /// file.
   512     DigraphReader(Digraph& digraph, const std::string& fn)
   513       : _is(new std::ifstream(fn.c_str())), local_is(true),
   514         _filename(fn), _digraph(digraph),
   515         _use_nodes(false), _use_arcs(false),
   516         _skip_nodes(false), _skip_arcs(false) {
   517       if (!(*_is)) {
   518         delete _is;
   519         throw IoError("Cannot open file", fn);
   520       }
   521     }
   522 
   523     /// \brief Constructor
   524     ///
   525     /// Construct a directed graph reader, which reads from the given
   526     /// file.
   527     DigraphReader(Digraph& digraph, const char* fn)
   528       : _is(new std::ifstream(fn)), local_is(true),
   529         _filename(fn), _digraph(digraph),
   530         _use_nodes(false), _use_arcs(false),
   531         _skip_nodes(false), _skip_arcs(false) {
   532       if (!(*_is)) {
   533         delete _is;
   534         throw IoError("Cannot open file", fn);
   535       }
   536     }
   537 
   538     /// \brief Destructor
   539     ~DigraphReader() {
   540       for (typename NodeMaps::iterator it = _node_maps.begin();
   541            it != _node_maps.end(); ++it) {
   542         delete it->second;
   543       }
   544 
   545       for (typename ArcMaps::iterator it = _arc_maps.begin();
   546            it != _arc_maps.end(); ++it) {
   547         delete it->second;
   548       }
   549 
   550       for (typename Attributes::iterator it = _attributes.begin();
   551            it != _attributes.end(); ++it) {
   552         delete it->second;
   553       }
   554 
   555       if (local_is) {
   556         delete _is;
   557       }
   558 
   559     }
   560 
   561   private:
   562 
   563     template <typename DGR>
   564     friend DigraphReader<DGR> digraphReader(DGR& digraph, std::istream& is);
   565     template <typename DGR>
   566     friend DigraphReader<DGR> digraphReader(DGR& digraph, 
   567                                             const std::string& fn);
   568     template <typename DGR>
   569     friend DigraphReader<DGR> digraphReader(DGR& digraph, const char *fn);
   570 
   571     DigraphReader(DigraphReader& other)
   572       : _is(other._is), local_is(other.local_is), _digraph(other._digraph),
   573         _use_nodes(other._use_nodes), _use_arcs(other._use_arcs),
   574         _skip_nodes(other._skip_nodes), _skip_arcs(other._skip_arcs) {
   575 
   576       other._is = 0;
   577       other.local_is = false;
   578 
   579       _node_index.swap(other._node_index);
   580       _arc_index.swap(other._arc_index);
   581 
   582       _node_maps.swap(other._node_maps);
   583       _arc_maps.swap(other._arc_maps);
   584       _attributes.swap(other._attributes);
   585 
   586       _nodes_caption = other._nodes_caption;
   587       _arcs_caption = other._arcs_caption;
   588       _attributes_caption = other._attributes_caption;
   589 
   590     }
   591 
   592     DigraphReader& operator=(const DigraphReader&);
   593 
   594   public:
   595 
   596     /// \name Reading rules
   597     /// @{
   598 
   599     /// \brief Node map reading rule
   600     ///
   601     /// Add a node map reading rule to the reader.
   602     template <typename Map>
   603     DigraphReader& nodeMap(const std::string& caption, Map& map) {
   604       checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();
   605       _reader_bits::MapStorageBase<Node>* storage =
   606         new _reader_bits::MapStorage<Node, Map>(map);
   607       _node_maps.push_back(std::make_pair(caption, storage));
   608       return *this;
   609     }
   610 
   611     /// \brief Node map reading rule
   612     ///
   613     /// Add a node map reading rule with specialized converter to the
   614     /// reader.
   615     template <typename Map, typename Converter>
   616     DigraphReader& nodeMap(const std::string& caption, Map& map,
   617                            const Converter& converter = Converter()) {
   618       checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();
   619       _reader_bits::MapStorageBase<Node>* storage =
   620         new _reader_bits::MapStorage<Node, Map, Converter>(map, converter);
   621       _node_maps.push_back(std::make_pair(caption, storage));
   622       return *this;
   623     }
   624 
   625     /// \brief Arc map reading rule
   626     ///
   627     /// Add an arc map reading rule to the reader.
   628     template <typename Map>
   629     DigraphReader& arcMap(const std::string& caption, Map& map) {
   630       checkConcept<concepts::WriteMap<Arc, typename Map::Value>, Map>();
   631       _reader_bits::MapStorageBase<Arc>* storage =
   632         new _reader_bits::MapStorage<Arc, Map>(map);
   633       _arc_maps.push_back(std::make_pair(caption, storage));
   634       return *this;
   635     }
   636 
   637     /// \brief Arc map reading rule
   638     ///
   639     /// Add an arc map reading rule with specialized converter to the
   640     /// reader.
   641     template <typename Map, typename Converter>
   642     DigraphReader& arcMap(const std::string& caption, Map& map,
   643                           const Converter& converter = Converter()) {
   644       checkConcept<concepts::WriteMap<Arc, typename Map::Value>, Map>();
   645       _reader_bits::MapStorageBase<Arc>* storage =
   646         new _reader_bits::MapStorage<Arc, Map, Converter>(map, converter);
   647       _arc_maps.push_back(std::make_pair(caption, storage));
   648       return *this;
   649     }
   650 
   651     /// \brief Attribute reading rule
   652     ///
   653     /// Add an attribute reading rule to the reader.
   654     template <typename Value>
   655     DigraphReader& attribute(const std::string& caption, Value& value) {
   656       _reader_bits::ValueStorageBase* storage =
   657         new _reader_bits::ValueStorage<Value>(value);
   658       _attributes.insert(std::make_pair(caption, storage));
   659       return *this;
   660     }
   661 
   662     /// \brief Attribute reading rule
   663     ///
   664     /// Add an attribute reading rule with specialized converter to the
   665     /// reader.
   666     template <typename Value, typename Converter>
   667     DigraphReader& attribute(const std::string& caption, Value& value,
   668                              const Converter& converter = Converter()) {
   669       _reader_bits::ValueStorageBase* storage =
   670         new _reader_bits::ValueStorage<Value, Converter>(value, converter);
   671       _attributes.insert(std::make_pair(caption, storage));
   672       return *this;
   673     }
   674 
   675     /// \brief Node reading rule
   676     ///
   677     /// Add a node reading rule to reader.
   678     DigraphReader& node(const std::string& caption, Node& node) {
   679       typedef _reader_bits::MapLookUpConverter<Node> Converter;
   680       Converter converter(_node_index);
   681       _reader_bits::ValueStorageBase* storage =
   682         new _reader_bits::ValueStorage<Node, Converter>(node, converter);
   683       _attributes.insert(std::make_pair(caption, storage));
   684       return *this;
   685     }
   686 
   687     /// \brief Arc reading rule
   688     ///
   689     /// Add an arc reading rule to reader.
   690     DigraphReader& arc(const std::string& caption, Arc& arc) {
   691       typedef _reader_bits::MapLookUpConverter<Arc> Converter;
   692       Converter converter(_arc_index);
   693       _reader_bits::ValueStorageBase* storage =
   694         new _reader_bits::ValueStorage<Arc, Converter>(arc, converter);
   695       _attributes.insert(std::make_pair(caption, storage));
   696       return *this;
   697     }
   698 
   699     /// @}
   700 
   701     /// \name Select section by name
   702     /// @{
   703 
   704     /// \brief Set \c \@nodes section to be read
   705     ///
   706     /// Set \c \@nodes section to be read
   707     DigraphReader& nodes(const std::string& caption) {
   708       _nodes_caption = caption;
   709       return *this;
   710     }
   711 
   712     /// \brief Set \c \@arcs section to be read
   713     ///
   714     /// Set \c \@arcs section to be read
   715     DigraphReader& arcs(const std::string& caption) {
   716       _arcs_caption = caption;
   717       return *this;
   718     }
   719 
   720     /// \brief Set \c \@attributes section to be read
   721     ///
   722     /// Set \c \@attributes section to be read
   723     DigraphReader& attributes(const std::string& caption) {
   724       _attributes_caption = caption;
   725       return *this;
   726     }
   727 
   728     /// @}
   729 
   730     /// \name Using previously constructed node or arc set
   731     /// @{
   732 
   733     /// \brief Use previously constructed node set
   734     ///
   735     /// Use previously constructed node set, and specify the node
   736     /// label map.
   737     template <typename Map>
   738     DigraphReader& useNodes(const Map& map) {
   739       checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();
   740       LEMON_ASSERT(!_use_nodes, "Multiple usage of useNodes() member");
   741       _use_nodes = true;
   742       _writer_bits::DefaultConverter<typename Map::Value> converter;
   743       for (NodeIt n(_digraph); n != INVALID; ++n) {
   744         _node_index.insert(std::make_pair(converter(map[n]), n));
   745       }
   746       return *this;
   747     }
   748 
   749     /// \brief Use previously constructed node set
   750     ///
   751     /// Use previously constructed node set, and specify the node
   752     /// label map and a functor which converts the label map values to
   753     /// \c std::string.
   754     template <typename Map, typename Converter>
   755     DigraphReader& useNodes(const Map& map,
   756                             const Converter& converter = Converter()) {
   757       checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();
   758       LEMON_ASSERT(!_use_nodes, "Multiple usage of useNodes() member");
   759       _use_nodes = true;
   760       for (NodeIt n(_digraph); n != INVALID; ++n) {
   761         _node_index.insert(std::make_pair(converter(map[n]), n));
   762       }
   763       return *this;
   764     }
   765 
   766     /// \brief Use previously constructed arc set
   767     ///
   768     /// Use previously constructed arc set, and specify the arc
   769     /// label map.
   770     template <typename Map>
   771     DigraphReader& useArcs(const Map& map) {
   772       checkConcept<concepts::ReadMap<Arc, typename Map::Value>, Map>();
   773       LEMON_ASSERT(!_use_arcs, "Multiple usage of useArcs() member");
   774       _use_arcs = true;
   775       _writer_bits::DefaultConverter<typename Map::Value> converter;
   776       for (ArcIt a(_digraph); a != INVALID; ++a) {
   777         _arc_index.insert(std::make_pair(converter(map[a]), a));
   778       }
   779       return *this;
   780     }
   781 
   782     /// \brief Use previously constructed arc set
   783     ///
   784     /// Use previously constructed arc set, and specify the arc
   785     /// label map and a functor which converts the label map values to
   786     /// \c std::string.
   787     template <typename Map, typename Converter>
   788     DigraphReader& useArcs(const Map& map,
   789                            const Converter& converter = Converter()) {
   790       checkConcept<concepts::ReadMap<Arc, typename Map::Value>, Map>();
   791       LEMON_ASSERT(!_use_arcs, "Multiple usage of useArcs() member");
   792       _use_arcs = true;
   793       for (ArcIt a(_digraph); a != INVALID; ++a) {
   794         _arc_index.insert(std::make_pair(converter(map[a]), a));
   795       }
   796       return *this;
   797     }
   798 
   799     /// \brief Skips the reading of node section
   800     ///
   801     /// Omit the reading of the node section. This implies that each node
   802     /// map reading rule will be abandoned, and the nodes of the graph
   803     /// will not be constructed, which usually cause that the arc set
   804     /// could not be read due to lack of node name resolving.
   805     /// Therefore \c skipArcs() function should also be used, or
   806     /// \c useNodes() should be used to specify the label of the nodes.
   807     DigraphReader& skipNodes() {
   808       LEMON_ASSERT(!_skip_nodes, "Skip nodes already set");
   809       _skip_nodes = true;
   810       return *this;
   811     }
   812 
   813     /// \brief Skips the reading of arc section
   814     ///
   815     /// Omit the reading of the arc section. This implies that each arc
   816     /// map reading rule will be abandoned, and the arcs of the graph
   817     /// will not be constructed.
   818     DigraphReader& skipArcs() {
   819       LEMON_ASSERT(!_skip_arcs, "Skip arcs already set");
   820       _skip_arcs = true;
   821       return *this;
   822     }
   823 
   824     /// @}
   825 
   826   private:
   827 
   828     bool readLine() {
   829       std::string str;
   830       while(++line_num, std::getline(*_is, str)) {
   831         line.clear(); line.str(str);
   832         char c;
   833         if (line >> std::ws >> c && c != '#') {
   834           line.putback(c);
   835           return true;
   836         }
   837       }
   838       return false;
   839     }
   840 
   841     bool readSuccess() {
   842       return static_cast<bool>(*_is);
   843     }
   844 
   845     void skipSection() {
   846       char c;
   847       while (readSuccess() && line >> c && c != '@') {
   848         readLine();
   849       }
   850       if (readSuccess()) {
   851         line.putback(c);
   852       }
   853     }
   854 
   855     void readNodes() {
   856 
   857       std::vector<int> map_index(_node_maps.size());
   858       int map_num, label_index;
   859 
   860       char c;
   861       if (!readLine() || !(line >> c) || c == '@') {
   862         if (readSuccess() && line) line.putback(c);
   863         if (!_node_maps.empty())
   864           throw FormatError("Cannot find map names");
   865         return;
   866       }
   867       line.putback(c);
   868 
   869       {
   870         std::map<std::string, int> maps;
   871 
   872         std::string map;
   873         int index = 0;
   874         while (_reader_bits::readToken(line, map)) {
   875           if (maps.find(map) != maps.end()) {
   876             std::ostringstream msg;
   877             msg << "Multiple occurence of node map: " << map;
   878             throw FormatError(msg.str());
   879           }
   880           maps.insert(std::make_pair(map, index));
   881           ++index;
   882         }
   883 
   884         for (int i = 0; i < static_cast<int>(_node_maps.size()); ++i) {
   885           std::map<std::string, int>::iterator jt =
   886             maps.find(_node_maps[i].first);
   887           if (jt == maps.end()) {
   888             std::ostringstream msg;
   889             msg << "Map not found: " << _node_maps[i].first;
   890             throw FormatError(msg.str());
   891           }
   892           map_index[i] = jt->second;
   893         }
   894 
   895         {
   896           std::map<std::string, int>::iterator jt = maps.find("label");
   897           if (jt != maps.end()) {
   898             label_index = jt->second;
   899           } else {
   900             label_index = -1;
   901           }
   902         }
   903         map_num = maps.size();
   904       }
   905 
   906       while (readLine() && line >> c && c != '@') {
   907         line.putback(c);
   908 
   909         std::vector<std::string> tokens(map_num);
   910         for (int i = 0; i < map_num; ++i) {
   911           if (!_reader_bits::readToken(line, tokens[i])) {
   912             std::ostringstream msg;
   913             msg << "Column not found (" << i + 1 << ")";
   914             throw FormatError(msg.str());
   915           }
   916         }
   917         if (line >> std::ws >> c)
   918           throw FormatError("Extra character at the end of line");
   919 
   920         Node n;
   921         if (!_use_nodes) {
   922           n = _digraph.addNode();
   923           if (label_index != -1)
   924             _node_index.insert(std::make_pair(tokens[label_index], n));
   925         } else {
   926           if (label_index == -1)
   927             throw FormatError("Label map not found");
   928           typename std::map<std::string, Node>::iterator it =
   929             _node_index.find(tokens[label_index]);
   930           if (it == _node_index.end()) {
   931             std::ostringstream msg;
   932             msg << "Node with label not found: " << tokens[label_index];
   933             throw FormatError(msg.str());
   934           }
   935           n = it->second;
   936         }
   937 
   938         for (int i = 0; i < static_cast<int>(_node_maps.size()); ++i) {
   939           _node_maps[i].second->set(n, tokens[map_index[i]]);
   940         }
   941 
   942       }
   943       if (readSuccess()) {
   944         line.putback(c);
   945       }
   946     }
   947 
   948     void readArcs() {
   949 
   950       std::vector<int> map_index(_arc_maps.size());
   951       int map_num, label_index;
   952 
   953       char c;
   954       if (!readLine() || !(line >> c) || c == '@') {
   955         if (readSuccess() && line) line.putback(c);
   956         if (!_arc_maps.empty())
   957           throw FormatError("Cannot find map names");
   958         return;
   959       }
   960       line.putback(c);
   961 
   962       {
   963         std::map<std::string, int> maps;
   964 
   965         std::string map;
   966         int index = 0;
   967         while (_reader_bits::readToken(line, map)) {
   968           if (maps.find(map) != maps.end()) {
   969             std::ostringstream msg;
   970             msg << "Multiple occurence of arc map: " << map;
   971             throw FormatError(msg.str());
   972           }
   973           maps.insert(std::make_pair(map, index));
   974           ++index;
   975         }
   976 
   977         for (int i = 0; i < static_cast<int>(_arc_maps.size()); ++i) {
   978           std::map<std::string, int>::iterator jt =
   979             maps.find(_arc_maps[i].first);
   980           if (jt == maps.end()) {
   981             std::ostringstream msg;
   982             msg << "Map not found: " << _arc_maps[i].first;
   983             throw FormatError(msg.str());
   984           }
   985           map_index[i] = jt->second;
   986         }
   987 
   988         {
   989           std::map<std::string, int>::iterator jt = maps.find("label");
   990           if (jt != maps.end()) {
   991             label_index = jt->second;
   992           } else {
   993             label_index = -1;
   994           }
   995         }
   996         map_num = maps.size();
   997       }
   998 
   999       while (readLine() && line >> c && c != '@') {
  1000         line.putback(c);
  1001 
  1002         std::string source_token;
  1003         std::string target_token;
  1004 
  1005         if (!_reader_bits::readToken(line, source_token))
  1006           throw FormatError("Source not found");
  1007 
  1008         if (!_reader_bits::readToken(line, target_token))
  1009           throw FormatError("Target not found");
  1010 
  1011         std::vector<std::string> tokens(map_num);
  1012         for (int i = 0; i < map_num; ++i) {
  1013           if (!_reader_bits::readToken(line, tokens[i])) {
  1014             std::ostringstream msg;
  1015             msg << "Column not found (" << i + 1 << ")";
  1016             throw FormatError(msg.str());
  1017           }
  1018         }
  1019         if (line >> std::ws >> c)
  1020           throw FormatError("Extra character at the end of line");
  1021 
  1022         Arc a;
  1023         if (!_use_arcs) {
  1024 
  1025           typename NodeIndex::iterator it;
  1026 
  1027           it = _node_index.find(source_token);
  1028           if (it == _node_index.end()) {
  1029             std::ostringstream msg;
  1030             msg << "Item not found: " << source_token;
  1031             throw FormatError(msg.str());
  1032           }
  1033           Node source = it->second;
  1034 
  1035           it = _node_index.find(target_token);
  1036           if (it == _node_index.end()) {
  1037             std::ostringstream msg;
  1038             msg << "Item not found: " << target_token;
  1039             throw FormatError(msg.str());
  1040           }
  1041           Node target = it->second;
  1042 
  1043           a = _digraph.addArc(source, target);
  1044           if (label_index != -1)
  1045             _arc_index.insert(std::make_pair(tokens[label_index], a));
  1046         } else {
  1047           if (label_index == -1)
  1048             throw FormatError("Label map not found");
  1049           typename std::map<std::string, Arc>::iterator it =
  1050             _arc_index.find(tokens[label_index]);
  1051           if (it == _arc_index.end()) {
  1052             std::ostringstream msg;
  1053             msg << "Arc with label not found: " << tokens[label_index];
  1054             throw FormatError(msg.str());
  1055           }
  1056           a = it->second;
  1057         }
  1058 
  1059         for (int i = 0; i < static_cast<int>(_arc_maps.size()); ++i) {
  1060           _arc_maps[i].second->set(a, tokens[map_index[i]]);
  1061         }
  1062 
  1063       }
  1064       if (readSuccess()) {
  1065         line.putback(c);
  1066       }
  1067     }
  1068 
  1069     void readAttributes() {
  1070 
  1071       std::set<std::string> read_attr;
  1072 
  1073       char c;
  1074       while (readLine() && line >> c && c != '@') {
  1075         line.putback(c);
  1076 
  1077         std::string attr, token;
  1078         if (!_reader_bits::readToken(line, attr))
  1079           throw FormatError("Attribute name not found");
  1080         if (!_reader_bits::readToken(line, token))
  1081           throw FormatError("Attribute value not found");
  1082         if (line >> c)
  1083           throw FormatError("Extra character at the end of line");
  1084 
  1085         {
  1086           std::set<std::string>::iterator it = read_attr.find(attr);
  1087           if (it != read_attr.end()) {
  1088             std::ostringstream msg;
  1089             msg << "Multiple occurence of attribute: " << attr;
  1090             throw FormatError(msg.str());
  1091           }
  1092           read_attr.insert(attr);
  1093         }
  1094 
  1095         {
  1096           typename Attributes::iterator it = _attributes.lower_bound(attr);
  1097           while (it != _attributes.end() && it->first == attr) {
  1098             it->second->set(token);
  1099             ++it;
  1100           }
  1101         }
  1102 
  1103       }
  1104       if (readSuccess()) {
  1105         line.putback(c);
  1106       }
  1107       for (typename Attributes::iterator it = _attributes.begin();
  1108            it != _attributes.end(); ++it) {
  1109         if (read_attr.find(it->first) == read_attr.end()) {
  1110           std::ostringstream msg;
  1111           msg << "Attribute not found: " << it->first;
  1112           throw FormatError(msg.str());
  1113         }
  1114       }
  1115     }
  1116 
  1117   public:
  1118 
  1119     /// \name Execution of the reader
  1120     /// @{
  1121 
  1122     /// \brief Start the batch processing
  1123     ///
  1124     /// This function starts the batch processing
  1125     void run() {
  1126       LEMON_ASSERT(_is != 0, "This reader assigned to an other reader");
  1127 
  1128       bool nodes_done = _skip_nodes;
  1129       bool arcs_done = _skip_arcs;
  1130       bool attributes_done = false;
  1131 
  1132       line_num = 0;
  1133       readLine();
  1134       skipSection();
  1135 
  1136       while (readSuccess()) {
  1137         try {
  1138           char c;
  1139           std::string section, caption;
  1140           line >> c;
  1141           _reader_bits::readToken(line, section);
  1142           _reader_bits::readToken(line, caption);
  1143 
  1144           if (line >> c)
  1145             throw FormatError("Extra character at the end of line");
  1146 
  1147           if (section == "nodes" && !nodes_done) {
  1148             if (_nodes_caption.empty() || _nodes_caption == caption) {
  1149               readNodes();
  1150               nodes_done = true;
  1151             }
  1152           } else if ((section == "arcs" || section == "edges") &&
  1153                      !arcs_done) {
  1154             if (_arcs_caption.empty() || _arcs_caption == caption) {
  1155               readArcs();
  1156               arcs_done = true;
  1157             }
  1158           } else if (section == "attributes" && !attributes_done) {
  1159             if (_attributes_caption.empty() || _attributes_caption == caption) {
  1160               readAttributes();
  1161               attributes_done = true;
  1162             }
  1163           } else {
  1164             readLine();
  1165             skipSection();
  1166           }
  1167         } catch (FormatError& error) {
  1168           error.line(line_num);
  1169           error.file(_filename);
  1170           throw;
  1171         }
  1172       }
  1173 
  1174       if (!nodes_done) {
  1175         throw FormatError("Section @nodes not found");
  1176       }
  1177 
  1178       if (!arcs_done) {
  1179         throw FormatError("Section @arcs not found");
  1180       }
  1181 
  1182       if (!attributes_done && !_attributes.empty()) {
  1183         throw FormatError("Section @attributes not found");
  1184       }
  1185 
  1186     }
  1187 
  1188     /// @}
  1189 
  1190   };
  1191 
  1192   /// \brief Return a \ref DigraphReader class
  1193   ///
  1194   /// This function just returns a \ref DigraphReader class.
  1195   /// \relates DigraphReader
  1196   template <typename Digraph>
  1197   DigraphReader<Digraph> digraphReader(Digraph& digraph, std::istream& is) {
  1198     DigraphReader<Digraph> tmp(digraph, is);
  1199     return tmp;
  1200   }
  1201 
  1202   /// \brief Return a \ref DigraphReader class
  1203   ///
  1204   /// This function just returns a \ref DigraphReader class.
  1205   /// \relates DigraphReader
  1206   template <typename Digraph>
  1207   DigraphReader<Digraph> digraphReader(Digraph& digraph,
  1208                                        const std::string& fn) {
  1209     DigraphReader<Digraph> tmp(digraph, fn);
  1210     return tmp;
  1211   }
  1212 
  1213   /// \brief Return a \ref DigraphReader class
  1214   ///
  1215   /// This function just returns a \ref DigraphReader class.
  1216   /// \relates DigraphReader
  1217   template <typename Digraph>
  1218   DigraphReader<Digraph> digraphReader(Digraph& digraph, const char* fn) {
  1219     DigraphReader<Digraph> tmp(digraph, fn);
  1220     return tmp;
  1221   }
  1222 
  1223   template <typename Graph>
  1224   class GraphReader;
  1225  
  1226   template <typename Graph>
  1227   GraphReader<Graph> graphReader(Graph& graph, 
  1228                                  std::istream& is = std::cin);
  1229   template <typename Graph>
  1230   GraphReader<Graph> graphReader(Graph& graph, const std::string& fn);
  1231   template <typename Graph>
  1232   GraphReader<Graph> graphReader(Graph& graph, const char *fn);
  1233 
  1234   /// \ingroup lemon_io
  1235   ///
  1236   /// \brief \ref lgf-format "LGF" reader for undirected graphs
  1237   ///
  1238   /// This utility reads an \ref lgf-format "LGF" file.
  1239   ///
  1240   /// It can be used almost the same way as \c DigraphReader.
  1241   /// The only difference is that this class can handle edges and
  1242   /// edge maps as well as arcs and arc maps.
  1243   ///
  1244   /// The columns in the \c \@edges (or \c \@arcs) section are the
  1245   /// edge maps. However, if there are two maps with the same name
  1246   /// prefixed with \c '+' and \c '-', then these can be read into an
  1247   /// arc map.  Similarly, an attribute can be read into an arc, if
  1248   /// it's value is an edge label prefixed with \c '+' or \c '-'.
  1249   template <typename GR>
  1250   class GraphReader {
  1251   public:
  1252 
  1253     typedef GR Graph;
  1254 
  1255   private:
  1256 
  1257     TEMPLATE_GRAPH_TYPEDEFS(Graph);
  1258 
  1259     std::istream* _is;
  1260     bool local_is;
  1261     std::string _filename;
  1262 
  1263     Graph& _graph;
  1264 
  1265     std::string _nodes_caption;
  1266     std::string _edges_caption;
  1267     std::string _attributes_caption;
  1268 
  1269     typedef std::map<std::string, Node> NodeIndex;
  1270     NodeIndex _node_index;
  1271     typedef std::map<std::string, Edge> EdgeIndex;
  1272     EdgeIndex _edge_index;
  1273 
  1274     typedef std::vector<std::pair<std::string,
  1275       _reader_bits::MapStorageBase<Node>*> > NodeMaps;
  1276     NodeMaps _node_maps;
  1277 
  1278     typedef std::vector<std::pair<std::string,
  1279       _reader_bits::MapStorageBase<Edge>*> > EdgeMaps;
  1280     EdgeMaps _edge_maps;
  1281 
  1282     typedef std::multimap<std::string, _reader_bits::ValueStorageBase*>
  1283       Attributes;
  1284     Attributes _attributes;
  1285 
  1286     bool _use_nodes;
  1287     bool _use_edges;
  1288 
  1289     bool _skip_nodes;
  1290     bool _skip_edges;
  1291 
  1292     int line_num;
  1293     std::istringstream line;
  1294 
  1295   public:
  1296 
  1297     /// \brief Constructor
  1298     ///
  1299     /// Construct an undirected graph reader, which reads from the given
  1300     /// input stream.
  1301     GraphReader(Graph& graph, std::istream& is = std::cin)
  1302       : _is(&is), local_is(false), _graph(graph),
  1303         _use_nodes(false), _use_edges(false),
  1304         _skip_nodes(false), _skip_edges(false) {}
  1305 
  1306     /// \brief Constructor
  1307     ///
  1308     /// Construct an undirected graph reader, which reads from the given
  1309     /// file.
  1310     GraphReader(Graph& graph, const std::string& fn)
  1311       : _is(new std::ifstream(fn.c_str())), local_is(true),
  1312         _filename(fn), _graph(graph),
  1313         _use_nodes(false), _use_edges(false),
  1314         _skip_nodes(false), _skip_edges(false) {
  1315       if (!(*_is)) {
  1316         delete _is;
  1317         throw IoError("Cannot open file", fn);
  1318       }
  1319     }
  1320 
  1321     /// \brief Constructor
  1322     ///
  1323     /// Construct an undirected graph reader, which reads from the given
  1324     /// file.
  1325     GraphReader(Graph& graph, const char* fn)
  1326       : _is(new std::ifstream(fn)), local_is(true),
  1327         _filename(fn), _graph(graph),
  1328         _use_nodes(false), _use_edges(false),
  1329         _skip_nodes(false), _skip_edges(false) {
  1330       if (!(*_is)) {
  1331         delete _is;
  1332         throw IoError("Cannot open file", fn);
  1333       }
  1334     }
  1335 
  1336     /// \brief Destructor
  1337     ~GraphReader() {
  1338       for (typename NodeMaps::iterator it = _node_maps.begin();
  1339            it != _node_maps.end(); ++it) {
  1340         delete it->second;
  1341       }
  1342 
  1343       for (typename EdgeMaps::iterator it = _edge_maps.begin();
  1344            it != _edge_maps.end(); ++it) {
  1345         delete it->second;
  1346       }
  1347 
  1348       for (typename Attributes::iterator it = _attributes.begin();
  1349            it != _attributes.end(); ++it) {
  1350         delete it->second;
  1351       }
  1352 
  1353       if (local_is) {
  1354         delete _is;
  1355       }
  1356 
  1357     }
  1358 
  1359   private:
  1360     template <typename Graph>
  1361     friend GraphReader<Graph> graphReader(Graph& graph, std::istream& is);
  1362     template <typename Graph>
  1363     friend GraphReader<Graph> graphReader(Graph& graph, const std::string& fn); 
  1364     template <typename Graph>
  1365     friend GraphReader<Graph> graphReader(Graph& graph, const char *fn);
  1366 
  1367     GraphReader(GraphReader& other)
  1368       : _is(other._is), local_is(other.local_is), _graph(other._graph),
  1369         _use_nodes(other._use_nodes), _use_edges(other._use_edges),
  1370         _skip_nodes(other._skip_nodes), _skip_edges(other._skip_edges) {
  1371 
  1372       other._is = 0;
  1373       other.local_is = false;
  1374 
  1375       _node_index.swap(other._node_index);
  1376       _edge_index.swap(other._edge_index);
  1377 
  1378       _node_maps.swap(other._node_maps);
  1379       _edge_maps.swap(other._edge_maps);
  1380       _attributes.swap(other._attributes);
  1381 
  1382       _nodes_caption = other._nodes_caption;
  1383       _edges_caption = other._edges_caption;
  1384       _attributes_caption = other._attributes_caption;
  1385 
  1386     }
  1387 
  1388     GraphReader& operator=(const GraphReader&);
  1389 
  1390   public:
  1391 
  1392     /// \name Reading rules
  1393     /// @{
  1394 
  1395     /// \brief Node map reading rule
  1396     ///
  1397     /// Add a node map reading rule to the reader.
  1398     template <typename Map>
  1399     GraphReader& nodeMap(const std::string& caption, Map& map) {
  1400       checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();
  1401       _reader_bits::MapStorageBase<Node>* storage =
  1402         new _reader_bits::MapStorage<Node, Map>(map);
  1403       _node_maps.push_back(std::make_pair(caption, storage));
  1404       return *this;
  1405     }
  1406 
  1407     /// \brief Node map reading rule
  1408     ///
  1409     /// Add a node map reading rule with specialized converter to the
  1410     /// reader.
  1411     template <typename Map, typename Converter>
  1412     GraphReader& nodeMap(const std::string& caption, Map& map,
  1413                            const Converter& converter = Converter()) {
  1414       checkConcept<concepts::WriteMap<Node, typename Map::Value>, Map>();
  1415       _reader_bits::MapStorageBase<Node>* storage =
  1416         new _reader_bits::MapStorage<Node, Map, Converter>(map, converter);
  1417       _node_maps.push_back(std::make_pair(caption, storage));
  1418       return *this;
  1419     }
  1420 
  1421     /// \brief Edge map reading rule
  1422     ///
  1423     /// Add an edge map reading rule to the reader.
  1424     template <typename Map>
  1425     GraphReader& edgeMap(const std::string& caption, Map& map) {
  1426       checkConcept<concepts::WriteMap<Edge, typename Map::Value>, Map>();
  1427       _reader_bits::MapStorageBase<Edge>* storage =
  1428         new _reader_bits::MapStorage<Edge, Map>(map);
  1429       _edge_maps.push_back(std::make_pair(caption, storage));
  1430       return *this;
  1431     }
  1432 
  1433     /// \brief Edge map reading rule
  1434     ///
  1435     /// Add an edge map reading rule with specialized converter to the
  1436     /// reader.
  1437     template <typename Map, typename Converter>
  1438     GraphReader& edgeMap(const std::string& caption, Map& map,
  1439                           const Converter& converter = Converter()) {
  1440       checkConcept<concepts::WriteMap<Edge, typename Map::Value>, Map>();
  1441       _reader_bits::MapStorageBase<Edge>* storage =
  1442         new _reader_bits::MapStorage<Edge, Map, Converter>(map, converter);
  1443       _edge_maps.push_back(std::make_pair(caption, storage));
  1444       return *this;
  1445     }
  1446 
  1447     /// \brief Arc map reading rule
  1448     ///
  1449     /// Add an arc map reading rule to the reader.
  1450     template <typename Map>
  1451     GraphReader& arcMap(const std::string& caption, Map& map) {
  1452       checkConcept<concepts::WriteMap<Arc, typename Map::Value>, Map>();
  1453       _reader_bits::MapStorageBase<Edge>* forward_storage =
  1454         new _reader_bits::GraphArcMapStorage<Graph, true, Map>(_graph, map);
  1455       _edge_maps.push_back(std::make_pair('+' + caption, forward_storage));
  1456       _reader_bits::MapStorageBase<Edge>* backward_storage =
  1457         new _reader_bits::GraphArcMapStorage<Graph, false, Map>(_graph, map);
  1458       _edge_maps.push_back(std::make_pair('-' + caption, backward_storage));
  1459       return *this;
  1460     }
  1461 
  1462     /// \brief Arc map reading rule
  1463     ///
  1464     /// Add an arc map reading rule with specialized converter to the
  1465     /// reader.
  1466     template <typename Map, typename Converter>
  1467     GraphReader& arcMap(const std::string& caption, Map& map,
  1468                           const Converter& converter = Converter()) {
  1469       checkConcept<concepts::WriteMap<Arc, typename Map::Value>, Map>();
  1470       _reader_bits::MapStorageBase<Edge>* forward_storage =
  1471         new _reader_bits::GraphArcMapStorage<Graph, true, Map, Converter>
  1472         (_graph, map, converter);
  1473       _edge_maps.push_back(std::make_pair('+' + caption, forward_storage));
  1474       _reader_bits::MapStorageBase<Edge>* backward_storage =
  1475         new _reader_bits::GraphArcMapStorage<Graph, false, Map, Converter>
  1476         (_graph, map, converter);
  1477       _edge_maps.push_back(std::make_pair('-' + caption, backward_storage));
  1478       return *this;
  1479     }
  1480 
  1481     /// \brief Attribute reading rule
  1482     ///
  1483     /// Add an attribute reading rule to the reader.
  1484     template <typename Value>
  1485     GraphReader& attribute(const std::string& caption, Value& value) {
  1486       _reader_bits::ValueStorageBase* storage =
  1487         new _reader_bits::ValueStorage<Value>(value);
  1488       _attributes.insert(std::make_pair(caption, storage));
  1489       return *this;
  1490     }
  1491 
  1492     /// \brief Attribute reading rule
  1493     ///
  1494     /// Add an attribute reading rule with specialized converter to the
  1495     /// reader.
  1496     template <typename Value, typename Converter>
  1497     GraphReader& attribute(const std::string& caption, Value& value,
  1498                              const Converter& converter = Converter()) {
  1499       _reader_bits::ValueStorageBase* storage =
  1500         new _reader_bits::ValueStorage<Value, Converter>(value, converter);
  1501       _attributes.insert(std::make_pair(caption, storage));
  1502       return *this;
  1503     }
  1504 
  1505     /// \brief Node reading rule
  1506     ///
  1507     /// Add a node reading rule to reader.
  1508     GraphReader& node(const std::string& caption, Node& node) {
  1509       typedef _reader_bits::MapLookUpConverter<Node> Converter;
  1510       Converter converter(_node_index);
  1511       _reader_bits::ValueStorageBase* storage =
  1512         new _reader_bits::ValueStorage<Node, Converter>(node, converter);
  1513       _attributes.insert(std::make_pair(caption, storage));
  1514       return *this;
  1515     }
  1516 
  1517     /// \brief Edge reading rule
  1518     ///
  1519     /// Add an edge reading rule to reader.
  1520     GraphReader& edge(const std::string& caption, Edge& edge) {
  1521       typedef _reader_bits::MapLookUpConverter<Edge> Converter;
  1522       Converter converter(_edge_index);
  1523       _reader_bits::ValueStorageBase* storage =
  1524         new _reader_bits::ValueStorage<Edge, Converter>(edge, converter);
  1525       _attributes.insert(std::make_pair(caption, storage));
  1526       return *this;
  1527     }
  1528 
  1529     /// \brief Arc reading rule
  1530     ///
  1531     /// Add an arc reading rule to reader.
  1532     GraphReader& arc(const std::string& caption, Arc& arc) {
  1533       typedef _reader_bits::GraphArcLookUpConverter<Graph> Converter;
  1534       Converter converter(_graph, _edge_index);
  1535       _reader_bits::ValueStorageBase* storage =
  1536         new _reader_bits::ValueStorage<Arc, Converter>(arc, converter);
  1537       _attributes.insert(std::make_pair(caption, storage));
  1538       return *this;
  1539     }
  1540 
  1541     /// @}
  1542 
  1543     /// \name Select section by name
  1544     /// @{
  1545 
  1546     /// \brief Set \c \@nodes section to be read
  1547     ///
  1548     /// Set \c \@nodes section to be read.
  1549     GraphReader& nodes(const std::string& caption) {
  1550       _nodes_caption = caption;
  1551       return *this;
  1552     }
  1553 
  1554     /// \brief Set \c \@edges section to be read
  1555     ///
  1556     /// Set \c \@edges section to be read.
  1557     GraphReader& edges(const std::string& caption) {
  1558       _edges_caption = caption;
  1559       return *this;
  1560     }
  1561 
  1562     /// \brief Set \c \@attributes section to be read
  1563     ///
  1564     /// Set \c \@attributes section to be read.
  1565     GraphReader& attributes(const std::string& caption) {
  1566       _attributes_caption = caption;
  1567       return *this;
  1568     }
  1569 
  1570     /// @}
  1571 
  1572     /// \name Using previously constructed node or edge set
  1573     /// @{
  1574 
  1575     /// \brief Use previously constructed node set
  1576     ///
  1577     /// Use previously constructed node set, and specify the node
  1578     /// label map.
  1579     template <typename Map>
  1580     GraphReader& useNodes(const Map& map) {
  1581       checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();
  1582       LEMON_ASSERT(!_use_nodes, "Multiple usage of useNodes() member");
  1583       _use_nodes = true;
  1584       _writer_bits::DefaultConverter<typename Map::Value> converter;
  1585       for (NodeIt n(_graph); n != INVALID; ++n) {
  1586         _node_index.insert(std::make_pair(converter(map[n]), n));
  1587       }
  1588       return *this;
  1589     }
  1590 
  1591     /// \brief Use previously constructed node set
  1592     ///
  1593     /// Use previously constructed node set, and specify the node
  1594     /// label map and a functor which converts the label map values to
  1595     /// \c std::string.
  1596     template <typename Map, typename Converter>
  1597     GraphReader& useNodes(const Map& map,
  1598                             const Converter& converter = Converter()) {
  1599       checkConcept<concepts::ReadMap<Node, typename Map::Value>, Map>();
  1600       LEMON_ASSERT(!_use_nodes, "Multiple usage of useNodes() member");
  1601       _use_nodes = true;
  1602       for (NodeIt n(_graph); n != INVALID; ++n) {
  1603         _node_index.insert(std::make_pair(converter(map[n]), n));
  1604       }
  1605       return *this;
  1606     }
  1607 
  1608     /// \brief Use previously constructed edge set
  1609     ///
  1610     /// Use previously constructed edge set, and specify the edge
  1611     /// label map.
  1612     template <typename Map>
  1613     GraphReader& useEdges(const Map& map) {
  1614       checkConcept<concepts::ReadMap<Edge, typename Map::Value>, Map>();
  1615       LEMON_ASSERT(!_use_edges, "Multiple usage of useEdges() member");
  1616       _use_edges = true;
  1617       _writer_bits::DefaultConverter<typename Map::Value> converter;
  1618       for (EdgeIt a(_graph); a != INVALID; ++a) {
  1619         _edge_index.insert(std::make_pair(converter(map[a]), a));
  1620       }
  1621       return *this;
  1622     }
  1623 
  1624     /// \brief Use previously constructed edge set
  1625     ///
  1626     /// Use previously constructed edge set, and specify the edge
  1627     /// label map and a functor which converts the label map values to
  1628     /// \c std::string.
  1629     template <typename Map, typename Converter>
  1630     GraphReader& useEdges(const Map& map,
  1631                             const Converter& converter = Converter()) {
  1632       checkConcept<concepts::ReadMap<Edge, typename Map::Value>, Map>();
  1633       LEMON_ASSERT(!_use_edges, "Multiple usage of useEdges() member");
  1634       _use_edges = true;
  1635       for (EdgeIt a(_graph); a != INVALID; ++a) {
  1636         _edge_index.insert(std::make_pair(converter(map[a]), a));
  1637       }
  1638       return *this;
  1639     }
  1640 
  1641     /// \brief Skip the reading of node section
  1642     ///
  1643     /// Omit the reading of the node section. This implies that each node
  1644     /// map reading rule will be abandoned, and the nodes of the graph
  1645     /// will not be constructed, which usually cause that the edge set
  1646     /// could not be read due to lack of node name
  1647     /// could not be read due to lack of node name resolving.
  1648     /// Therefore \c skipEdges() function should also be used, or
  1649     /// \c useNodes() should be used to specify the label of the nodes.
  1650     GraphReader& skipNodes() {
  1651       LEMON_ASSERT(!_skip_nodes, "Skip nodes already set");
  1652       _skip_nodes = true;
  1653       return *this;
  1654     }
  1655 
  1656     /// \brief Skip the reading of edge section
  1657     ///
  1658     /// Omit the reading of the edge section. This implies that each edge
  1659     /// map reading rule will be abandoned, and the edges of the graph
  1660     /// will not be constructed.
  1661     GraphReader& skipEdges() {
  1662       LEMON_ASSERT(!_skip_edges, "Skip edges already set");
  1663       _skip_edges = true;
  1664       return *this;
  1665     }
  1666 
  1667     /// @}
  1668 
  1669   private:
  1670 
  1671     bool readLine() {
  1672       std::string str;
  1673       while(++line_num, std::getline(*_is, str)) {
  1674         line.clear(); line.str(str);
  1675         char c;
  1676         if (line >> std::ws >> c && c != '#') {
  1677           line.putback(c);
  1678           return true;
  1679         }
  1680       }
  1681       return false;
  1682     }
  1683 
  1684     bool readSuccess() {
  1685       return static_cast<bool>(*_is);
  1686     }
  1687 
  1688     void skipSection() {
  1689       char c;
  1690       while (readSuccess() && line >> c && c != '@') {
  1691         readLine();
  1692       }
  1693       if (readSuccess()) {
  1694         line.putback(c);
  1695       }
  1696     }
  1697 
  1698     void readNodes() {
  1699 
  1700       std::vector<int> map_index(_node_maps.size());
  1701       int map_num, label_index;
  1702 
  1703       char c;
  1704       if (!readLine() || !(line >> c) || c == '@') {
  1705         if (readSuccess() && line) line.putback(c);
  1706         if (!_node_maps.empty())
  1707           throw FormatError("Cannot find map names");
  1708         return;
  1709       }
  1710       line.putback(c);
  1711 
  1712       {
  1713         std::map<std::string, int> maps;
  1714 
  1715         std::string map;
  1716         int index = 0;
  1717         while (_reader_bits::readToken(line, map)) {
  1718           if (maps.find(map) != maps.end()) {
  1719             std::ostringstream msg;
  1720             msg << "Multiple occurence of node map: " << map;
  1721             throw FormatError(msg.str());
  1722           }
  1723           maps.insert(std::make_pair(map, index));
  1724           ++index;
  1725         }
  1726 
  1727         for (int i = 0; i < static_cast<int>(_node_maps.size()); ++i) {
  1728           std::map<std::string, int>::iterator jt =
  1729             maps.find(_node_maps[i].first);
  1730           if (jt == maps.end()) {
  1731             std::ostringstream msg;
  1732             msg << "Map not found: " << _node_maps[i].first;
  1733             throw FormatError(msg.str());
  1734           }
  1735           map_index[i] = jt->second;
  1736         }
  1737 
  1738         {
  1739           std::map<std::string, int>::iterator jt = maps.find("label");
  1740           if (jt != maps.end()) {
  1741             label_index = jt->second;
  1742           } else {
  1743             label_index = -1;
  1744           }
  1745         }
  1746         map_num = maps.size();
  1747       }
  1748 
  1749       while (readLine() && line >> c && c != '@') {
  1750         line.putback(c);
  1751 
  1752         std::vector<std::string> tokens(map_num);
  1753         for (int i = 0; i < map_num; ++i) {
  1754           if (!_reader_bits::readToken(line, tokens[i])) {
  1755             std::ostringstream msg;
  1756             msg << "Column not found (" << i + 1 << ")";
  1757             throw FormatError(msg.str());
  1758           }
  1759         }
  1760         if (line >> std::ws >> c)
  1761           throw FormatError("Extra character at the end of line");
  1762 
  1763         Node n;
  1764         if (!_use_nodes) {
  1765           n = _graph.addNode();
  1766           if (label_index != -1)
  1767             _node_index.insert(std::make_pair(tokens[label_index], n));
  1768         } else {
  1769           if (label_index == -1)
  1770             throw FormatError("Label map not found");
  1771           typename std::map<std::string, Node>::iterator it =
  1772             _node_index.find(tokens[label_index]);
  1773           if (it == _node_index.end()) {
  1774             std::ostringstream msg;
  1775             msg << "Node with label not found: " << tokens[label_index];
  1776             throw FormatError(msg.str());
  1777           }
  1778           n = it->second;
  1779         }
  1780 
  1781         for (int i = 0; i < static_cast<int>(_node_maps.size()); ++i) {
  1782           _node_maps[i].second->set(n, tokens[map_index[i]]);
  1783         }
  1784 
  1785       }
  1786       if (readSuccess()) {
  1787         line.putback(c);
  1788       }
  1789     }
  1790 
  1791     void readEdges() {
  1792 
  1793       std::vector<int> map_index(_edge_maps.size());
  1794       int map_num, label_index;
  1795 
  1796       char c;
  1797       if (!readLine() || !(line >> c) || c == '@') {
  1798         if (readSuccess() && line) line.putback(c);
  1799         if (!_edge_maps.empty())
  1800           throw FormatError("Cannot find map names");
  1801         return;
  1802       }
  1803       line.putback(c);
  1804 
  1805       {
  1806         std::map<std::string, int> maps;
  1807 
  1808         std::string map;
  1809         int index = 0;
  1810         while (_reader_bits::readToken(line, map)) {
  1811           if (maps.find(map) != maps.end()) {
  1812             std::ostringstream msg;
  1813             msg << "Multiple occurence of edge map: " << map;
  1814             throw FormatError(msg.str());
  1815           }
  1816           maps.insert(std::make_pair(map, index));
  1817           ++index;
  1818         }
  1819 
  1820         for (int i = 0; i < static_cast<int>(_edge_maps.size()); ++i) {
  1821           std::map<std::string, int>::iterator jt =
  1822             maps.find(_edge_maps[i].first);
  1823           if (jt == maps.end()) {
  1824             std::ostringstream msg;
  1825             msg << "Map not found: " << _edge_maps[i].first;
  1826             throw FormatError(msg.str());
  1827           }
  1828           map_index[i] = jt->second;
  1829         }
  1830 
  1831         {
  1832           std::map<std::string, int>::iterator jt = maps.find("label");
  1833           if (jt != maps.end()) {
  1834             label_index = jt->second;
  1835           } else {
  1836             label_index = -1;
  1837           }
  1838         }
  1839         map_num = maps.size();
  1840       }
  1841 
  1842       while (readLine() && line >> c && c != '@') {
  1843         line.putback(c);
  1844 
  1845         std::string source_token;
  1846         std::string target_token;
  1847 
  1848         if (!_reader_bits::readToken(line, source_token))
  1849           throw FormatError("Node u not found");
  1850 
  1851         if (!_reader_bits::readToken(line, target_token))
  1852           throw FormatError("Node v not found");
  1853 
  1854         std::vector<std::string> tokens(map_num);
  1855         for (int i = 0; i < map_num; ++i) {
  1856           if (!_reader_bits::readToken(line, tokens[i])) {
  1857             std::ostringstream msg;
  1858             msg << "Column not found (" << i + 1 << ")";
  1859             throw FormatError(msg.str());
  1860           }
  1861         }
  1862         if (line >> std::ws >> c)
  1863           throw FormatError("Extra character at the end of line");
  1864 
  1865         Edge e;
  1866         if (!_use_edges) {
  1867 
  1868           typename NodeIndex::iterator it;
  1869 
  1870           it = _node_index.find(source_token);
  1871           if (it == _node_index.end()) {
  1872             std::ostringstream msg;
  1873             msg << "Item not found: " << source_token;
  1874             throw FormatError(msg.str());
  1875           }
  1876           Node source = it->second;
  1877 
  1878           it = _node_index.find(target_token);
  1879           if (it == _node_index.end()) {
  1880             std::ostringstream msg;
  1881             msg << "Item not found: " << target_token;
  1882             throw FormatError(msg.str());
  1883           }
  1884           Node target = it->second;
  1885 
  1886           e = _graph.addEdge(source, target);
  1887           if (label_index != -1)
  1888             _edge_index.insert(std::make_pair(tokens[label_index], e));
  1889         } else {
  1890           if (label_index == -1)
  1891             throw FormatError("Label map not found");
  1892           typename std::map<std::string, Edge>::iterator it =
  1893             _edge_index.find(tokens[label_index]);
  1894           if (it == _edge_index.end()) {
  1895             std::ostringstream msg;
  1896             msg << "Edge with label not found: " << tokens[label_index];
  1897             throw FormatError(msg.str());
  1898           }
  1899           e = it->second;
  1900         }
  1901 
  1902         for (int i = 0; i < static_cast<int>(_edge_maps.size()); ++i) {
  1903           _edge_maps[i].second->set(e, tokens[map_index[i]]);
  1904         }
  1905 
  1906       }
  1907       if (readSuccess()) {
  1908         line.putback(c);
  1909       }
  1910     }
  1911 
  1912     void readAttributes() {
  1913 
  1914       std::set<std::string> read_attr;
  1915 
  1916       char c;
  1917       while (readLine() && line >> c && c != '@') {
  1918         line.putback(c);
  1919 
  1920         std::string attr, token;
  1921         if (!_reader_bits::readToken(line, attr))
  1922           throw FormatError("Attribute name not found");
  1923         if (!_reader_bits::readToken(line, token))
  1924           throw FormatError("Attribute value not found");
  1925         if (line >> c)
  1926           throw FormatError("Extra character at the end of line");
  1927 
  1928         {
  1929           std::set<std::string>::iterator it = read_attr.find(attr);
  1930           if (it != read_attr.end()) {
  1931             std::ostringstream msg;
  1932             msg << "Multiple occurence of attribute: " << attr;
  1933             throw FormatError(msg.str());
  1934           }
  1935           read_attr.insert(attr);
  1936         }
  1937 
  1938         {
  1939           typename Attributes::iterator it = _attributes.lower_bound(attr);
  1940           while (it != _attributes.end() && it->first == attr) {
  1941             it->second->set(token);
  1942             ++it;
  1943           }
  1944         }
  1945 
  1946       }
  1947       if (readSuccess()) {
  1948         line.putback(c);
  1949       }
  1950       for (typename Attributes::iterator it = _attributes.begin();
  1951            it != _attributes.end(); ++it) {
  1952         if (read_attr.find(it->first) == read_attr.end()) {
  1953           std::ostringstream msg;
  1954           msg << "Attribute not found: " << it->first;
  1955           throw FormatError(msg.str());
  1956         }
  1957       }
  1958     }
  1959 
  1960   public:
  1961 
  1962     /// \name Execution of the reader
  1963     /// @{
  1964 
  1965     /// \brief Start the batch processing
  1966     ///
  1967     /// This function starts the batch processing
  1968     void run() {
  1969 
  1970       LEMON_ASSERT(_is != 0, "This reader assigned to an other reader");
  1971 
  1972       bool nodes_done = _skip_nodes;
  1973       bool edges_done = _skip_edges;
  1974       bool attributes_done = false;
  1975 
  1976       line_num = 0;
  1977       readLine();
  1978       skipSection();
  1979 
  1980       while (readSuccess()) {
  1981         try {
  1982           char c;
  1983           std::string section, caption;
  1984           line >> c;
  1985           _reader_bits::readToken(line, section);
  1986           _reader_bits::readToken(line, caption);
  1987 
  1988           if (line >> c)
  1989             throw FormatError("Extra character at the end of line");
  1990 
  1991           if (section == "nodes" && !nodes_done) {
  1992             if (_nodes_caption.empty() || _nodes_caption == caption) {
  1993               readNodes();
  1994               nodes_done = true;
  1995             }
  1996           } else if ((section == "edges" || section == "arcs") &&
  1997                      !edges_done) {
  1998             if (_edges_caption.empty() || _edges_caption == caption) {
  1999               readEdges();
  2000               edges_done = true;
  2001             }
  2002           } else if (section == "attributes" && !attributes_done) {
  2003             if (_attributes_caption.empty() || _attributes_caption == caption) {
  2004               readAttributes();
  2005               attributes_done = true;
  2006             }
  2007           } else {
  2008             readLine();
  2009             skipSection();
  2010           }
  2011         } catch (FormatError& error) {
  2012           error.line(line_num);
  2013           error.file(_filename);
  2014           throw;
  2015         }
  2016       }
  2017 
  2018       if (!nodes_done) {
  2019         throw FormatError("Section @nodes not found");
  2020       }
  2021 
  2022       if (!edges_done) {
  2023         throw FormatError("Section @edges not found");
  2024       }
  2025 
  2026       if (!attributes_done && !_attributes.empty()) {
  2027         throw FormatError("Section @attributes not found");
  2028       }
  2029 
  2030     }
  2031 
  2032     /// @}
  2033 
  2034   };
  2035 
  2036   /// \brief Return a \ref GraphReader class
  2037   ///
  2038   /// This function just returns a \ref GraphReader class.
  2039   /// \relates GraphReader
  2040   template <typename Graph>
  2041   GraphReader<Graph> graphReader(Graph& graph, std::istream& is) {
  2042     GraphReader<Graph> tmp(graph, is);
  2043     return tmp;
  2044   }
  2045 
  2046   /// \brief Return a \ref GraphReader class
  2047   ///
  2048   /// This function just returns a \ref GraphReader class.
  2049   /// \relates GraphReader
  2050   template <typename Graph>
  2051   GraphReader<Graph> graphReader(Graph& graph, const std::string& fn) {
  2052     GraphReader<Graph> tmp(graph, fn);
  2053     return tmp;
  2054   }
  2055 
  2056   /// \brief Return a \ref GraphReader class
  2057   ///
  2058   /// This function just returns a \ref GraphReader class.
  2059   /// \relates GraphReader
  2060   template <typename Graph>
  2061   GraphReader<Graph> graphReader(Graph& graph, const char* fn) {
  2062     GraphReader<Graph> tmp(graph, fn);
  2063     return tmp;
  2064   }
  2065 
  2066   class SectionReader;
  2067 
  2068   SectionReader sectionReader(std::istream& is);
  2069   SectionReader sectionReader(const std::string& fn);
  2070   SectionReader sectionReader(const char* fn);
  2071 
  2072   /// \ingroup lemon_io
  2073   ///
  2074   /// \brief Section reader class
  2075   ///
  2076   /// In the \ref lgf-format "LGF" file extra sections can be placed,
  2077   /// which contain any data in arbitrary format. Such sections can be
  2078   /// read with this class. A reading rule can be added to the class
  2079   /// with two different functions. With the \c sectionLines() function a
  2080   /// functor can process the section line-by-line, while with the \c
  2081   /// sectionStream() member the section can be read from an input
  2082   /// stream.
  2083   class SectionReader {
  2084   private:
  2085 
  2086     std::istream* _is;
  2087     bool local_is;
  2088     std::string _filename;
  2089 
  2090     typedef std::map<std::string, _reader_bits::Section*> Sections;
  2091     Sections _sections;
  2092 
  2093     int line_num;
  2094     std::istringstream line;
  2095 
  2096   public:
  2097 
  2098     /// \brief Constructor
  2099     ///
  2100     /// Construct a section reader, which reads from the given input
  2101     /// stream.
  2102     SectionReader(std::istream& is)
  2103       : _is(&is), local_is(false) {}
  2104 
  2105     /// \brief Constructor
  2106     ///
  2107     /// Construct a section reader, which reads from the given file.
  2108     SectionReader(const std::string& fn)
  2109       : _is(new std::ifstream(fn.c_str())), local_is(true),
  2110         _filename(fn) {
  2111       if (!(*_is)) {
  2112         delete _is;
  2113         throw IoError("Cannot open file", fn);
  2114       }
  2115     }
  2116 
  2117     /// \brief Constructor
  2118     ///
  2119     /// Construct a section reader, which reads from the given file.
  2120     SectionReader(const char* fn)
  2121       : _is(new std::ifstream(fn)), local_is(true),
  2122         _filename(fn) {
  2123       if (!(*_is)) {
  2124         delete _is;
  2125         throw IoError("Cannot open file", fn);
  2126       }
  2127     }
  2128 
  2129     /// \brief Destructor
  2130     ~SectionReader() {
  2131       for (Sections::iterator it = _sections.begin();
  2132            it != _sections.end(); ++it) {
  2133         delete it->second;
  2134       }
  2135 
  2136       if (local_is) {
  2137         delete _is;
  2138       }
  2139 
  2140     }
  2141 
  2142   private:
  2143 
  2144     friend SectionReader sectionReader(std::istream& is);
  2145     friend SectionReader sectionReader(const std::string& fn);
  2146     friend SectionReader sectionReader(const char* fn);
  2147 
  2148     SectionReader(SectionReader& other)
  2149       : _is(other._is), local_is(other.local_is) {
  2150 
  2151       other._is = 0;
  2152       other.local_is = false;
  2153 
  2154       _sections.swap(other._sections);
  2155     }
  2156 
  2157     SectionReader& operator=(const SectionReader&);
  2158 
  2159   public:
  2160 
  2161     /// \name Section readers
  2162     /// @{
  2163 
  2164     /// \brief Add a section processor with line oriented reading
  2165     ///
  2166     /// The first parameter is the type descriptor of the section, the
  2167     /// second is a functor, which takes just one \c std::string
  2168     /// parameter. At the reading process, each line of the section
  2169     /// will be given to the functor object. However, the empty lines
  2170     /// and the comment lines are filtered out, and the leading
  2171     /// whitespaces are trimmed from each processed string.
  2172     ///
  2173     /// For example let's see a section, which contain several
  2174     /// integers, which should be inserted into a vector.
  2175     ///\code
  2176     ///  @numbers
  2177     ///  12 45 23
  2178     ///  4
  2179     ///  23 6
  2180     ///\endcode
  2181     ///
  2182     /// The functor is implemented as a struct:
  2183     ///\code
  2184     ///  struct NumberSection {
  2185     ///    std::vector<int>& _data;
  2186     ///    NumberSection(std::vector<int>& data) : _data(data) {}
  2187     ///    void operator()(const std::string& line) {
  2188     ///      std::istringstream ls(line);
  2189     ///      int value;
  2190     ///      while (ls >> value) _data.push_back(value);
  2191     ///    }
  2192     ///  };
  2193     ///
  2194     ///  // ...
  2195     ///
  2196     ///  reader.sectionLines("numbers", NumberSection(vec));
  2197     ///\endcode
  2198     template <typename Functor>
  2199     SectionReader& sectionLines(const std::string& type, Functor functor) {
  2200       LEMON_ASSERT(!type.empty(), "Type is empty.");
  2201       LEMON_ASSERT(_sections.find(type) == _sections.end(),
  2202                    "Multiple reading of section.");
  2203       _sections.insert(std::make_pair(type,
  2204         new _reader_bits::LineSection<Functor>(functor)));
  2205       return *this;
  2206     }
  2207 
  2208 
  2209     /// \brief Add a section processor with stream oriented reading
  2210     ///
  2211     /// The first parameter is the type of the section, the second is
  2212     /// a functor, which takes an \c std::istream& and an \c int&
  2213     /// parameter, the latter regard to the line number of stream. The
  2214     /// functor can read the input while the section go on, and the
  2215     /// line number should be modified accordingly.
  2216     template <typename Functor>
  2217     SectionReader& sectionStream(const std::string& type, Functor functor) {
  2218       LEMON_ASSERT(!type.empty(), "Type is empty.");
  2219       LEMON_ASSERT(_sections.find(type) == _sections.end(),
  2220                    "Multiple reading of section.");
  2221       _sections.insert(std::make_pair(type,
  2222          new _reader_bits::StreamSection<Functor>(functor)));
  2223       return *this;
  2224     }
  2225 
  2226     /// @}
  2227 
  2228   private:
  2229 
  2230     bool readLine() {
  2231       std::string str;
  2232       while(++line_num, std::getline(*_is, str)) {
  2233         line.clear(); line.str(str);
  2234         char c;
  2235         if (line >> std::ws >> c && c != '#') {
  2236           line.putback(c);
  2237           return true;
  2238         }
  2239       }
  2240       return false;
  2241     }
  2242 
  2243     bool readSuccess() {
  2244       return static_cast<bool>(*_is);
  2245     }
  2246 
  2247     void skipSection() {
  2248       char c;
  2249       while (readSuccess() && line >> c && c != '@') {
  2250         readLine();
  2251       }
  2252       if (readSuccess()) {
  2253         line.putback(c);
  2254       }
  2255     }
  2256 
  2257   public:
  2258 
  2259 
  2260     /// \name Execution of the reader
  2261     /// @{
  2262 
  2263     /// \brief Start the batch processing
  2264     ///
  2265     /// This function starts the batch processing.
  2266     void run() {
  2267 
  2268       LEMON_ASSERT(_is != 0, "This reader assigned to an other reader");
  2269 
  2270       std::set<std::string> extra_sections;
  2271 
  2272       line_num = 0;
  2273       readLine();
  2274       skipSection();
  2275 
  2276       while (readSuccess()) {
  2277         try {
  2278           char c;
  2279           std::string section, caption;
  2280           line >> c;
  2281           _reader_bits::readToken(line, section);
  2282           _reader_bits::readToken(line, caption);
  2283 
  2284           if (line >> c)
  2285             throw FormatError("Extra character at the end of line");
  2286 
  2287           if (extra_sections.find(section) != extra_sections.end()) {
  2288             std::ostringstream msg;
  2289             msg << "Multiple occurence of section: " << section;
  2290             throw FormatError(msg.str());
  2291           }
  2292           Sections::iterator it = _sections.find(section);
  2293           if (it != _sections.end()) {
  2294             extra_sections.insert(section);
  2295             it->second->process(*_is, line_num);
  2296           }
  2297           readLine();
  2298           skipSection();
  2299         } catch (FormatError& error) {
  2300           error.line(line_num);
  2301           error.file(_filename);
  2302           throw;
  2303         }
  2304       }
  2305       for (Sections::iterator it = _sections.begin();
  2306            it != _sections.end(); ++it) {
  2307         if (extra_sections.find(it->first) == extra_sections.end()) {
  2308           std::ostringstream os;
  2309           os << "Cannot find section: " << it->first;
  2310           throw FormatError(os.str());
  2311         }
  2312       }
  2313     }
  2314 
  2315     /// @}
  2316 
  2317   };
  2318 
  2319   /// \brief Return a \ref SectionReader class
  2320   ///
  2321   /// This function just returns a \ref SectionReader class.
  2322   /// \relates SectionReader
  2323   inline SectionReader sectionReader(std::istream& is) {
  2324     SectionReader tmp(is);
  2325     return tmp;
  2326   }
  2327 
  2328   /// \brief Return a \ref SectionReader class
  2329   ///
  2330   /// This function just returns a \ref SectionReader class.
  2331   /// \relates SectionReader
  2332   inline SectionReader sectionReader(const std::string& fn) {
  2333     SectionReader tmp(fn);
  2334     return tmp;
  2335   }
  2336 
  2337   /// \brief Return a \ref SectionReader class
  2338   ///
  2339   /// This function just returns a \ref SectionReader class.
  2340   /// \relates SectionReader
  2341   inline SectionReader sectionReader(const char* fn) {
  2342     SectionReader tmp(fn);
  2343     return tmp;
  2344   }
  2345 
  2346   /// \ingroup lemon_io
  2347   ///
  2348   /// \brief Reader for the contents of the \ref lgf-format "LGF" file
  2349   ///
  2350   /// This class can be used to read the sections, the map names and
  2351   /// the attributes from a file. Usually, the LEMON programs know
  2352   /// that, which type of graph, which maps and which attributes
  2353   /// should be read from a file, but in general tools (like glemon)
  2354   /// the contents of an LGF file should be guessed somehow. This class
  2355   /// reads the graph and stores the appropriate information for
  2356   /// reading the graph.
  2357   ///
  2358   ///\code
  2359   /// LgfContents contents("graph.lgf");
  2360   /// contents.run();
  2361   ///
  2362   /// // Does it contain any node section and arc section?
  2363   /// if (contents.nodeSectionNum() == 0 || contents.arcSectionNum()) {
  2364   ///   std::cerr << "Failure, cannot find graph." << std::endl;
  2365   ///   return -1;
  2366   /// }
  2367   /// std::cout << "The name of the default node section: "
  2368   ///           << contents.nodeSection(0) << std::endl;
  2369   /// std::cout << "The number of the arc maps: "
  2370   ///           << contents.arcMaps(0).size() << std::endl;
  2371   /// std::cout << "The name of second arc map: "
  2372   ///           << contents.arcMaps(0)[1] << std::endl;
  2373   ///\endcode
  2374   class LgfContents {
  2375   private:
  2376 
  2377     std::istream* _is;
  2378     bool local_is;
  2379 
  2380     std::vector<std::string> _node_sections;
  2381     std::vector<std::string> _edge_sections;
  2382     std::vector<std::string> _attribute_sections;
  2383     std::vector<std::string> _extra_sections;
  2384 
  2385     std::vector<bool> _arc_sections;
  2386 
  2387     std::vector<std::vector<std::string> > _node_maps;
  2388     std::vector<std::vector<std::string> > _edge_maps;
  2389 
  2390     std::vector<std::vector<std::string> > _attributes;
  2391 
  2392 
  2393     int line_num;
  2394     std::istringstream line;
  2395 
  2396   public:
  2397 
  2398     /// \brief Constructor
  2399     ///
  2400     /// Construct an \e LGF contents reader, which reads from the given
  2401     /// input stream.
  2402     LgfContents(std::istream& is)
  2403       : _is(&is), local_is(false) {}
  2404 
  2405     /// \brief Constructor
  2406     ///
  2407     /// Construct an \e LGF contents reader, which reads from the given
  2408     /// file.
  2409     LgfContents(const std::string& fn)
  2410       : _is(new std::ifstream(fn.c_str())), local_is(true) {
  2411       if (!(*_is)) {
  2412         delete _is;
  2413         throw IoError("Cannot open file", fn);
  2414       }
  2415     }
  2416 
  2417     /// \brief Constructor
  2418     ///
  2419     /// Construct an \e LGF contents reader, which reads from the given
  2420     /// file.
  2421     LgfContents(const char* fn)
  2422       : _is(new std::ifstream(fn)), local_is(true) {
  2423       if (!(*_is)) {
  2424         delete _is;
  2425         throw IoError("Cannot open file", fn);
  2426       }
  2427     }
  2428 
  2429     /// \brief Destructor
  2430     ~LgfContents() {
  2431       if (local_is) delete _is;
  2432     }
  2433 
  2434   private:
  2435 
  2436     LgfContents(const LgfContents&);
  2437     LgfContents& operator=(const LgfContents&);
  2438 
  2439   public:
  2440 
  2441 
  2442     /// \name Node sections
  2443     /// @{
  2444 
  2445     /// \brief Gives back the number of node sections in the file.
  2446     ///
  2447     /// Gives back the number of node sections in the file.
  2448     int nodeSectionNum() const {
  2449       return _node_sections.size();
  2450     }
  2451 
  2452     /// \brief Returns the node section name at the given position.
  2453     ///
  2454     /// Returns the node section name at the given position.
  2455     const std::string& nodeSection(int i) const {
  2456       return _node_sections[i];
  2457     }
  2458 
  2459     /// \brief Gives back the node maps for the given section.
  2460     ///
  2461     /// Gives back the node maps for the given section.
  2462     const std::vector<std::string>& nodeMapNames(int i) const {
  2463       return _node_maps[i];
  2464     }
  2465 
  2466     /// @}
  2467 
  2468     /// \name Arc/Edge sections
  2469     /// @{
  2470 
  2471     /// \brief Gives back the number of arc/edge sections in the file.
  2472     ///
  2473     /// Gives back the number of arc/edge sections in the file.
  2474     /// \note It is synonym of \c edgeSectionNum().
  2475     int arcSectionNum() const {
  2476       return _edge_sections.size();
  2477     }
  2478 
  2479     /// \brief Returns the arc/edge section name at the given position.
  2480     ///
  2481     /// Returns the arc/edge section name at the given position.
  2482     /// \note It is synonym of \c edgeSection().
  2483     const std::string& arcSection(int i) const {
  2484       return _edge_sections[i];
  2485     }
  2486 
  2487     /// \brief Gives back the arc/edge maps for the given section.
  2488     ///
  2489     /// Gives back the arc/edge maps for the given section.
  2490     /// \note It is synonym of \c edgeMapNames().
  2491     const std::vector<std::string>& arcMapNames(int i) const {
  2492       return _edge_maps[i];
  2493     }
  2494 
  2495     /// @}
  2496 
  2497     /// \name Synonyms
  2498     /// @{
  2499 
  2500     /// \brief Gives back the number of arc/edge sections in the file.
  2501     ///
  2502     /// Gives back the number of arc/edge sections in the file.
  2503     /// \note It is synonym of \c arcSectionNum().
  2504     int edgeSectionNum() const {
  2505       return _edge_sections.size();
  2506     }
  2507 
  2508     /// \brief Returns the section name at the given position.
  2509     ///
  2510     /// Returns the section name at the given position.
  2511     /// \note It is synonym of \c arcSection().
  2512     const std::string& edgeSection(int i) const {
  2513       return _edge_sections[i];
  2514     }
  2515 
  2516     /// \brief Gives back the edge maps for the given section.
  2517     ///
  2518     /// Gives back the edge maps for the given section.
  2519     /// \note It is synonym of \c arcMapNames().
  2520     const std::vector<std::string>& edgeMapNames(int i) const {
  2521       return _edge_maps[i];
  2522     }
  2523 
  2524     /// @}
  2525 
  2526     /// \name Attribute sections
  2527     /// @{
  2528 
  2529     /// \brief Gives back the number of attribute sections in the file.
  2530     ///
  2531     /// Gives back the number of attribute sections in the file.
  2532     int attributeSectionNum() const {
  2533       return _attribute_sections.size();
  2534     }
  2535 
  2536     /// \brief Returns the attribute section name at the given position.
  2537     ///
  2538     /// Returns the attribute section name at the given position.
  2539     const std::string& attributeSectionNames(int i) const {
  2540       return _attribute_sections[i];
  2541     }
  2542 
  2543     /// \brief Gives back the attributes for the given section.
  2544     ///
  2545     /// Gives back the attributes for the given section.
  2546     const std::vector<std::string>& attributes(int i) const {
  2547       return _attributes[i];
  2548     }
  2549 
  2550     /// @}
  2551 
  2552     /// \name Extra sections
  2553     /// @{
  2554 
  2555     /// \brief Gives back the number of extra sections in the file.
  2556     ///
  2557     /// Gives back the number of extra sections in the file.
  2558     int extraSectionNum() const {
  2559       return _extra_sections.size();
  2560     }
  2561 
  2562     /// \brief Returns the extra section type at the given position.
  2563     ///
  2564     /// Returns the section type at the given position.
  2565     const std::string& extraSection(int i) const {
  2566       return _extra_sections[i];
  2567     }
  2568 
  2569     /// @}
  2570 
  2571   private:
  2572 
  2573     bool readLine() {
  2574       std::string str;
  2575       while(++line_num, std::getline(*_is, str)) {
  2576         line.clear(); line.str(str);
  2577         char c;
  2578         if (line >> std::ws >> c && c != '#') {
  2579           line.putback(c);
  2580           return true;
  2581         }
  2582       }
  2583       return false;
  2584     }
  2585 
  2586     bool readSuccess() {
  2587       return static_cast<bool>(*_is);
  2588     }
  2589 
  2590     void skipSection() {
  2591       char c;
  2592       while (readSuccess() && line >> c && c != '@') {
  2593         readLine();
  2594       }
  2595       if (readSuccess()) {
  2596         line.putback(c);
  2597       }
  2598     }
  2599 
  2600     void readMaps(std::vector<std::string>& maps) {
  2601       char c;
  2602       if (!readLine() || !(line >> c) || c == '@') {
  2603         if (readSuccess() && line) line.putback(c);
  2604         return;
  2605       }
  2606       line.putback(c);
  2607       std::string map;
  2608       while (_reader_bits::readToken(line, map)) {
  2609         maps.push_back(map);
  2610       }
  2611     }
  2612 
  2613     void readAttributes(std::vector<std::string>& attrs) {
  2614       readLine();
  2615       char c;
  2616       while (readSuccess() && line >> c && c != '@') {
  2617         line.putback(c);
  2618         std::string attr;
  2619         _reader_bits::readToken(line, attr);
  2620         attrs.push_back(attr);
  2621         readLine();
  2622       }
  2623       line.putback(c);
  2624     }
  2625 
  2626   public:
  2627 
  2628     /// \name Execution of the contents reader
  2629     /// @{
  2630 
  2631     /// \brief Starts the reading
  2632     ///
  2633     /// This function starts the reading.
  2634     void run() {
  2635 
  2636       readLine();
  2637       skipSection();
  2638 
  2639       while (readSuccess()) {
  2640 
  2641         char c;
  2642         line >> c;
  2643 
  2644         std::string section, caption;
  2645         _reader_bits::readToken(line, section);
  2646         _reader_bits::readToken(line, caption);
  2647 
  2648         if (section == "nodes") {
  2649           _node_sections.push_back(caption);
  2650           _node_maps.push_back(std::vector<std::string>());
  2651           readMaps(_node_maps.back());
  2652           readLine(); skipSection();
  2653         } else if (section == "arcs" || section == "edges") {
  2654           _edge_sections.push_back(caption);
  2655           _arc_sections.push_back(section == "arcs");
  2656           _edge_maps.push_back(std::vector<std::string>());
  2657           readMaps(_edge_maps.back());
  2658           readLine(); skipSection();
  2659         } else if (section == "attributes") {
  2660           _attribute_sections.push_back(caption);
  2661           _attributes.push_back(std::vector<std::string>());
  2662           readAttributes(_attributes.back());
  2663         } else {
  2664           _extra_sections.push_back(section);
  2665           readLine(); skipSection();
  2666         }
  2667       }
  2668     }
  2669 
  2670     /// @}
  2671 
  2672   };
  2673 }
  2674 
  2675 #endif