/* -*- C++ -*-

  * lemon/bits/item_reader.h - Part of LEMON, a generic C++ optimization library

  *

  * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport

  * (Egervary Research Group on Combinatorial Optimization, EGRES).

  *

  * Permission to use, modify and distribute this software is granted

  * provided that this copyright notice appears in all copies. For

  * precise terms see the accompanying LICENSE file.

  *

  * This software is provided "AS IS" with no warranty of any kind,

  * express or implied, and with no claim as to its suitability for any

  * purpose.

  *

  */

 /// @defgroup item_io Item Readers and Writers

 /// @ingroup io_group

 /// \brief Item Readers and Writers

 /// 

 /// The Input-Output classes can handle more data type by example

 /// as map or attribute value. Each of these should be written and

 /// read some way. The module make possible to do this.  

 /// \ingroup item_io

 /// \file

 /// \brief Item reader bits for lemon input.

 #ifndef LEMON_BITS_ITEM_READER_H

 #define LEMON_BITS_ITEM_READER_H

 #include <iostream>

 #include <string>

 #include <vector>

 #include <deque>

 #include <list>

 #include <set>

 namespace lemon {

   template <typename Value>

   class DefaultReader;

   /// \ingroup item_io

   ///

   /// \brief Reader class for quoted strings.

   ///

   /// Reader class for quoted strings. It can process the escape

   /// sequences in the string.

   ///

   /// \author Balazs Dezso

   class QuotedStringReader {

   public:

     /// \brief The value type of reader.

     ///

     /// The value type of reader.

     typedef std::string Value;

     /// \brief Constructor for the reader.

     ///

     /// Constructor for the reader. If the given parameter is true

     /// the reader processes the escape sequences.

     QuotedStringReader(bool _escaped = true) 

       : escaped(_escaped) {}

     /// \brief Reads a quoted string from the given stream.

     ///

     /// Reads a quoted string from the given stream.

     void read(std::istream& is, std::string& value) const {

       char c;

       value.clear();

       is >> std::ws;

       if (!is.get(c) || c != '\"') 

 	throw DataFormatError("Quoted string format error");

       while (is.get(c) && c != '\"') {

 	if (escaped && c == '\\') {

 	  value += readEscape(is);

 	} else {

 	  value += c;

 	}

       }

       if (!is) throw DataFormatError("Quoted string format error");

     }

   private:

     static char readEscape(std::istream& is) {

       char c;

       switch (is.get(c), c) {

       case '\\':

 	return '\\';

       case '\"':

 	return '\"';

       case '\'':

 	return '\'';

       case '\?':

 	return '\?';

       case 'a':

 	return '\a';

       case 'b':

 	return '\b';

       case 'f':

 	return '\f';

       case 'n':

 	return '\n';

       case 'r':

 	return '\r';

       case 't':

 	return '\t';

       case 'v':

 	return '\v';

       case 'x':

 	{

 	  int code;

 	  if (!is.get(c) || !isHex(c)) 

 	    throw DataFormatError("Escape format error");

 	  else if (code = valueHex(c), !is.get(c) || !isHex(c)) is.putback(c);

 	  else code = code * 16 + valueHex(c);

 	  return code;

 	}

       default:

 	{

 	  int code;

 	  if (!isOct(c)) 

 	    throw DataFormatError("Escape format error");

 	  else if (code = valueOct(c), !is.get(c) || !isOct(c)) 

 	    is.putback(c);

 	  else if (code = code * 8 + valueOct(c), !is.get(c) || !isOct(c)) 

 	    is.putback(c);

 	  else code = code * 8 + valueOct(c);

 	  return code;

 	}	      

       } 

     }

     static bool isOct(char c) {

       return '0' <= c && c <='7'; 

     }

     static int valueOct(char c) {

       return c - '0';

     }

    static bool isHex(char c) {

       return ('0' <= c && c <= '9') || 

 	('a' <= c && c <= 'z') || 

 	('A' <= c && c <= 'Z'); 

     }

     static int valueHex(char c) {

       if ('0' <= c && c <= '9') return c - '0';

       if ('a' <= c && c <= 'z') return c - 'a' + 10;

       return c - 'A' + 10;

     }

     bool escaped;

   };

   /// \ingroup item_io

   /// \brief Reader for standard containers.

   ///

   /// Reader for back insertable standard containers. The representation

   /// of the container is the values enumerated between an open and a

   /// close parse. 

   ///

   /// \author Balazs Dezso

   template <

     typename _Container, 

     typename _ItemReader = DefaultReader<typename _Container::value_type> 

   >

   class PushBackReader {

   public:

     typedef _Container Value;

     typedef _ItemReader ItemReader;

   private:

     ItemReader item_reader;

   public:

     /// \brief Reads the values into the container from the given stream.

     ///

     /// Reads the values into the container from the given stream.

     void read(std::istream& is, Value& value) const {

       char c;

       if (!(is >> c) || c != '(') 

 	throw DataFormatError("PushBackReader format error");

       while (is >> c && c != ')') {

 	is.putback(c);

 	typename ItemReader::Value item;

 	item_reader.read(is, item);

 	value.push_back(item);

       }

       if (!is) throw DataFormatError("PushBackReader format error");

       is.putback(c);

     }

   };

   /// \ingroup item_io

   ///

   /// \brief Reader for standard containers.

   ///

   /// Reader for insertable standard containers. The representation

   /// of the container is the values enumerated between an open and a

   /// close parse. 

   ///

   /// \author Balazs Dezso

   template <

     typename _Container, 

     typename _ItemReader = DefaultReader<typename _Container::value_type> 

   >

   class InsertReader {

   public:

     typedef _Container Value;

     typedef _ItemReader ItemReader;

   private:

     ItemReader item_reader;

   public:

     /// \brief Reads the values into the container from the given stream.

     ///

     /// Reads the values into the container from the given stream.

     void read(std::istream& is, Value& value) const {

       char c;

       if (!(is >> c) || c != '(') 

 	throw DataFormatError("InsertReader format error");

       while (is >> c && c != ')') {

 	is.putback(c);

 	typename ItemReader::Value item;

 	item_reader.read(is, item);

 	value.insert(item);

       }

       if (!is) throw DataFormatError("PushBackReader format error");

       is.putback(c);

     }

   };

   /// \ingroup item_io

   /// \brief Reader for parsed string.

   ///

   /// Reader for parsed strings. You can define the open and close

   /// parse characters. It reads from the input a character sequence

   /// which is right parsed.

   ///

   /// \author Balazs Dezso

   class ParsedStringReader {

   public:

     typedef std::string Value;

     /// \brief Constructor.

     ///

     /// Constructor for ParsedStringReader. You can give as parameter

     /// the open and close parse characters.

     ParsedStringReader(char _open = '(', char _close = ')')

       : open(_open), close(_close) {}

     /// \brief Reads the parsed string from the given stream.

     ///

     /// Reads the parsed string from the given stream.

     void read(std::istream& is, Value& value) const {

       char c;

       if (!(is >> c) || c != open) {

 	throw DataFormatError("ParsedStringReader format error");

       }

       value += c;

       int counter = 1;

       while (counter > 0 && is >> c) {

 	if (c == close) {

 	  --counter;

 	} else if (c == open) {

 	  ++counter;

 	}

 	value += c;

       }

       if (!is) {

 	throw DataFormatError("ParsedStrinReader format error");

       }

     }

   private:

     char open, close;

   };

   /// \ingroup item_io

   /// \brief Reader for read the whole line.

   ///

   /// Reader for read the whole line.

   ///

   /// \author Balazs Dezso

   class LineReader {

   public:

     typedef std::string Value;

     /// \brief Constructor.

     ///

     /// Constructor for the LineReader. If the given parameter is

     /// true then the spaces before the first not space character are

     /// skipped.

     LineReader(bool _skipSpaces = true) : skipSpaces(_skipSpaces) {}

     /// \brief Reads the line from the given stream.

     ///

     /// Reads the line from the given stream.

     void read(std::istream& is, Value& value) {

       if (skipSpaces) is >> std::ws;

       if (!getline(is, value)) {

 	throw DataFormatError("LineReader forma error");

       }

     }

   private:

     bool skipSpaces;

   };

   /// \ingroup item_io

   /// 

   /// \brief The default item reader template class.

   ///

   /// The default item reader template class. If some section reader

   /// needs to read a value from a stream it will give the default way for it.

   ///

   /// \author Balazs Dezso

   template <typename _Value>

   class DefaultReader {

   public:

     /// The value type.

     typedef _Value Value;

     /// \brief Reads a value from the given stream.

     ///

     /// Reads a value from the given stream.

     void read(std::istream& is, Value& value) const {

       if (!(is >> value)) 

 	throw DataFormatError("DefaultReader format error");

     }

   };

   template <>

   class DefaultReader<std::string> {

   public:

     typedef std::string Value;

     void read(std::istream& is, Value& value) const {

       char c;

       if (!(is >> std::ws >> c)) return;

       is.putback(c);

       switch (c) {

       case '\"':

 	QuotedStringReader().read(is, value);

 	break;

       case '(':

 	ParsedStringReader().read(is, value);

 	break;

       case '[':

 	ParsedStringReader('[', ']').read(is, value);

 	break;

       case '/':

 	ParsedStringReader('/', '/').read(is, value);

 	break;

       default:

 	if (!(is >> value)) 

 	  throw DataFormatError("DefaultReader format error");

 	break;

       }

     }

   };

   template <typename Item>

   class DefaultReader<std::vector<Item> > 

     : public PushBackReader<std::vector<Item> > {};

   template <typename Item>

   class DefaultReader<std::deque<Item> > 

     : public PushBackReader<std::deque<Item> > {};

   template <typename Item>

   class DefaultReader<std::list<Item> > 

     : public PushBackReader<std::list<Item> > {};

   template <typename Item>

   class DefaultReader<std::set<Item> > 

     : public InsertReader<std::set<Item> > {};

   template <typename Item>

   class DefaultReader<std::multiset<Item> > 

     : public InsertReader<std::multiset<Item> > {};

   /// \ingroup item_io

   /// 

   /// \brief The default item reader for skipping a value in the stream.

   ///

   /// The default item reader for skipping a value in the stream.

   ///

   /// \author Balazs Dezso

   class DefaultSkipper : public DefaultReader<std::string> {};

   /// \ingroup item_io  

   /// \brief Standard ReaderTraits for the GraphReader class.

   ///

   /// Standard ReaderTraits for the GraphReader class.

   /// It defines standard reading method for all type of value. 

   /// \author Balazs Dezso

   struct DefaultReaderTraits {

     template <typename _Value>

     struct Reader : DefaultReader<_Value> {};

     typedef DefaultSkipper Skipper;

   };

 }

 #endif