source: GTP/trunk/Lib/Vis/Preprocessing/src/gzstream.h @ 2176

// ============================================================================
// 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: 1.1 $
// Revision_date : $Date: 2004/02/16 14:46:00 $
// Author(s)     : Deepak Bandyopadhyay, Lutz Kettner
// 
// Standard streambuf implementation following Nicolai Josuttis, "The 
// Standard C++ Library".
// ============================================================================

#ifndef GZSTREAM_H
#define GZSTREAM_H 1

#include <zlib.h>

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

#ifdef GZSTREAM_NAMESPACE
namespace GZSTREAM_NAMESPACE {
#endif

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

   // size of data buff
#define gzbufferSize  303   



#define STREAMBUF std::streambuf 
#define ISTREAM std::istream
#define OSTREAM std::ostream

//#define STREAMBUF streambuf 
//#define ISTREAM istream
//#define OSTREAM ostream

class gzstreambuf : public STREAMBUF {

private:
    // totals 512 bytes under g++ for igzstream at the end.

    gzFile           file;               // file handle for compressed file
    char             buffer[gzbufferSize]; // data buffer
    char             opened;             // open/close state of stream
    int              mode;               // I/O mode

    int flush_buffer();
public:
    gzstreambuf() : opened(0) {
        setp( buffer, buffer + (gzbufferSize-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
    }
    int is_open() const { return opened; }
    gzstreambuf* open( const char* name, int open_mode);
    gzstreambuf* close();
    ~gzstreambuf() { close(); }
  
    virtual int     overflow( int c = EOF);
    virtual int     underflow();
    virtual int     sync();

};

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; }
  int is_open() const { return buf.is_open(); }
};

// ----------------------------------------------------------------------------
// 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 : public gzstreambase, public ISTREAM {
  
  public:
    igzstream() : gzstreambase(), ISTREAM( &buf )  {} 
    
    igzstream( const char* name, int open_mode = std::ios::in)
      : gzstreambase( name, open_mode), ISTREAM( &buf) {}
    
    gzstreambuf* rdbuf() { return gzstreambase::rdbuf(); }
    
    void open( const char* name, int open_mode = std::ios::in) {
      gzstreambase::open( name, open_mode);
    }
  };
  
class ogzstream : public gzstreambase, public OSTREAM {
  
public:
  ogzstream() : OSTREAM( &buf) {}
  ogzstream( const char* name, int mode = std::ios::out)
    : gzstreambase( name, mode), 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 //