/* -*- 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