openfoam/src/OpenFOAM/db/IOstreams/gzstream/gzstream.h

// ============================================================================
// 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".
// ============================================================================

#ifndef GZSTREAM_H
#define GZSTREAM_H 1

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

//#define GZSTREAM_NAMESPACE gzstream

#ifdef GZSTREAM_NAMESPACE
namespace GZSTREAM_NAMESPACE {
#endif

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

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

class gzstreambuf
   : public std::streambuf
{
private:

   //------------------------------------

   static const int bufferSize = 47+256;
   // totals 512 bytes under g++ for igzstream at the end.

   //------------------------------------
   gzFile           file;
   char             buffer[bufferSize];
   char             opened;
   int              mode;


   //------------------------------------

   int flush_buffer();

public:

   //------------------------------------

   gzstreambuf()
      : opened(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
   }
   ~gzstreambuf()
   {
      close();
   }

   //------------------------------------

   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
   : virtual public std::ios
{
protected:

   //------------------------------------

   gzstreambuf buf;

public:

   //------------------------------------

   gzstreambase()
   {
      init(&buf);
   }
   gzstreambase( const char* _name, int _open_mode );
   ~gzstreambase();

   //------------------------------------

   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
   : public std::istream
   , public gzstreambase
{
public:

   //------------------------------------

   igzstream()
      : std::istream( &buf)
   {}
   igzstream( const char*  _name,
              int          _open_mode = std::ios::in )
      : std::istream( &buf )
      , gzstreambase( _name, _open_mode )
   {}

   //------------------------------------

   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
   : public gzstreambase
   , public std::ostream
{
public:

   //------------------------------------

   ogzstream()
      : std::ostream( &buf)
   {}
   explicit
   ogzstream( const char* _name,
              int         _open_mode = std::ios::out )
      : gzstreambase( _name, _open_mode )
      , std::ostream( &buf)
   {}

   //------------------------------------

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

#ifdef GZSTREAM_NAMESPACE
} // namespace GZSTREAM_NAMESPACE
#endif

#endif // GZSTREAM_H
// ============================================================================
// EOF //