gzstream.h

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#ifdef SOPLEX_WITH_ZLIB

// ============================================================================
// gzstream, C++ iostream classes wrapping the zlib compression library.
// Copyright (C) 2001  Deepak Bandyopadhyay, Lutz Kettner
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
// ============================================================================
//
// File          : gzstream.h
// Revision      : $Revision: 1.8 $
// Revision_date : $Date: 2005/11/09 13:53:50 $
// Author(s)     : Deepak Bandyopadhyay, Lutz Kettner
//
// Standard streambuf implementation following Nicolai Josuttis, "The
// Standard C++ Library".
// ============================================================================

/**@file gzstream.h
 * @brief Utilities for handling gzipped input and output streams.
 */
#ifndef _GZSTREAM_H_
#define _GZSTREAM_H_ 1

// standard C++ with new header file names and std:: namespace
#include <iostream>
#include <fstream>
#include <cstring>
#include <zlib.h>

#define SOPLEX_GZSTREAM_NAMESPACE gzstream

#ifdef SOPLEX_GZSTREAM_NAMESPACE
namespace SOPLEX_GZSTREAM_NAMESPACE
{
#endif

// ----------------------------------------------------------------------------
//    Internal classes to implement gzstream. See below for user classes.
// ----------------------------------------------------------------------------

// ----------------------------------------------------------------------------
//    class gzstreambuf
// ----------------------------------------------------------------------------

/**@class gzstreambuf
   @brief Internal class to implement gzstream.
*/
class gzstreambuf
   : public std::streambuf
{
private:

   //------------------------------------
   /**@name Types */
   ///@{
   ///
   static const int bufferSize = 47 + 256; ///< size of data buff
   // totals 512 bytes under g++ for igzstream at the end.
   ///@}

   //------------------------------------
   /**@name Data */
   ///@{
   gzFile           file;               ///< file handle for compressed file
   char             buffer[bufferSize]; ///< data buffer
   char             opened;             ///< open/close state of stream
   unsigned int     mode;               ///< I/O mode
   ///@}

   //------------------------------------
   /**@name Internal helpers */
   ///@{
   ///
   int flush_buffer();
   ///@}

public:

   //------------------------------------
   /**@name Construction / destruction */
   ///@{
   /// default constructor
   gzstreambuf()
      : file(0)
      , opened(0)
      , mode(0)
   {
      setp(buffer, buffer + (bufferSize - 1));
      setg(buffer + 4,      // beginning of putback area
           buffer + 4,     // read position
           buffer + 4);    // end position
      // ASSERT: both input & output capabilities will not be used together
   }

   /// copy constructor
   gzstreambuf(const gzstreambuf& sb)
      : std::streambuf()
   {
      operator=(sb);
   }
   /// copy assignment operator
   gzstreambuf& operator=(const gzstreambuf& sb)
   {
      std::streambuf::operator=(sb);

      if(this != &sb)
      {
         opened = sb.opened;
         mode   = sb.mode;
         file  = sb.file;
         std::strncpy(buffer, sb.buffer, bufferSize);
      }

      return *this;
   }

   /// destructor
   ~gzstreambuf()
   {
      close();
   }
   ///@}

   //------------------------------------
   /**@name Interface */
   ///@{
   ///
   int is_open()
   {
      return opened;
   }
   ///
   gzstreambuf* open(const char* name, int open_mode);
   ///
   gzstreambuf* close();
   ///
   virtual int     overflow(int c = EOF);
   ///
   virtual int     underflow();
   ///
   virtual int     sync();
   ///@}
};

// ----------------------------------------------------------------------------
//    class gzstreambase
// ----------------------------------------------------------------------------

/**@class gzstreambase
   @brief Internal class to implement gzstream.
*/
class gzstreambase
   : virtual public std::ios
{
protected:

   //------------------------------------
   /**@name Data */
   ///@{
   ///
   gzstreambuf buf;
   ///@}

public:

   //------------------------------------
   /**@name Construction / destruction */
   ///@{
   /// default constructor
   gzstreambase()
   {
      init(&buf);
   }
   /// full constructor
   gzstreambase(const char* _name, int _open_mode);
   /// destructor
   ~gzstreambase();
   ///@}

   //------------------------------------
   /**@name Interface */
   ///@{
   ///
   void open(const char* _name, int _open_mode);
   ///
   void close();
   ///
   gzstreambuf* rdbuf()
   {
      return &buf;
   }
   ///@}
};

// ----------------------------------------------------------------------------
// User classes. Use igzstream and ogzstream analogously to ifstream and
// ofstream respectively. They read and write files based on the gz*
// function interface of the zlib. Files are compatible with gzip compression.
// ----------------------------------------------------------------------------

// ----------------------------------------------------------------------------
//    class igzstream
// ----------------------------------------------------------------------------

/**@class igzstream
   @brief Class to implement a gzip'd input stream.
*/
class igzstream
   : public std::istream
   , public gzstreambase
{
public:

   //------------------------------------
   /**@name Construction / destruction */
   ///@{
   /// default constructor
   igzstream()
      : std::istream(&buf)
   {}
   /// full constructor
   igzstream(const char*  _name,
             int          _open_mode = std::ios::in)
      : std::istream(&buf)
      , gzstreambase(_name, _open_mode)
   {}
   ///@}

   //------------------------------------
   /**@name Interface */
   ///@{
   ///
   gzstreambuf* rdbuf()
   {
      return gzstreambase::rdbuf();
   }
   ///
   void open(const char*  _name,
             int          _open_mode = std::ios::in)
   {
      gzstreambase::open(_name, _open_mode);
   }
   ///@}
};

// ----------------------------------------------------------------------------
//    class ogzstream
// ----------------------------------------------------------------------------

/**@class ogzstream
   @brief Class to implement a gzip'd output stream.
*/
class ogzstream
   : public gzstreambase
   , public std::ostream
{
public:

   //------------------------------------
   /**@name Construction / destruction */
   ///@{
   /// default constructor
   ogzstream()
      : std::ostream(&buf)
   {}
   /// full constructor
   explicit
   ogzstream(const char* _name,
             int         _open_mode = std::ios::out)
      : gzstreambase(_name, _open_mode)
      , std::ostream(&buf)
   {}
   ///@}

   //------------------------------------
   /**@name Interface */
   ///@{
   ///
   gzstreambuf* rdbuf()
   {
      return gzstreambase::rdbuf();
   }
   ///
   void open(const char*  _name,
             int          _open_mode = std::ios::out)
   {
      gzstreambase::open(_name, _open_mode);
   }
};

#ifdef SOPLEX_GZSTREAM_NAMESPACE
} // namespace SOPLEX_GZSTREAM_NAMESPACE
#endif

#endif // _GZSTREAM_H_
// ============================================================================
// EOF //

#endif