lemon/lgf_reader.h
author Peter Kovacs <kpeter@inf.elte.hu>
Thu, 09 Oct 2008 13:27:35 +0200
changeset 314 2cc60866a0c9
parent 295 7c796c1cf1b0
child 319 5e12d7734036
permissions -rw-r--r--
Doc reorganization + improvements

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