source: GTP/trunk/App/Demos/Vis/FriendlyCulling/VboFormatConverter/gzstream.cpp @ 3107

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

#include "gzstream.h"
#include <string.h>  // for memcpy

#ifdef GZSTREAM_NAMESPACE
namespace GZSTREAM_NAMESPACE {
#endif

// ----------------------------------------------------------------------------
// Internal classes to implement gzstream. See header file for user classes.
// ----------------------------------------------------------------------------

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

gzstreambuf*
gzstreambuf::open( const char* name, int open_mode) {
  if ( is_open() )
    return (gzstreambuf*)0;
  mode = open_mode;
  // no append nor read/write mode
  if ((mode & std::ios::ate) || (mode & std::ios::app)
      || ((mode & std::ios::in) && (mode & std::ios::out)))
    return (gzstreambuf*)0;
  char fmode[10];
  char* fmodeptr = fmode;
  if ( mode & std::ios::in)
    *fmodeptr++ = 'r';
  else
    if ( mode & std::ios::out)
      *fmodeptr++ = 'w';
  *fmodeptr++ = 'b';
  *fmodeptr = '\0';
  file = gzopen( name, fmode);
  if (file == 0)
    return (gzstreambuf*)0;
  opened = 1;
  return this;
}
  
gzstreambuf *
gzstreambuf::close() {
  if ( is_open()) {
    sync();
    opened = 0;
    if ( gzclose( file) == Z_OK)
      return this;
  }
  return (gzstreambuf*)0;
}
  
int
gzstreambuf::underflow() { // used for input buffer only
  if ( gptr() && ( gptr() < egptr()))
    return * reinterpret_cast<unsigned char *>( gptr());
  
  if ( ! (mode & std::ios::in) || ! opened)
    return EOF;
  // Josuttis' implementation of inbuf
  int n_putback = gptr() - eback();
  if ( n_putback > 4)
    n_putback = 4;
  memcpy( buffer + (4 - n_putback), gptr() - n_putback, n_putback);
  
  int num = gzread( file, buffer+4, gzbufferSize-4);
  if (num <= 0) // ERROR or EOF
    return EOF;
  
  // reset buffer pointers
  setg( buffer + (4 - n_putback),   // beginning of putback area
        buffer + 4,                 // read position
        buffer + 4 + num);          // end of buffer
  
  // return next character
  return * reinterpret_cast<unsigned char *>( gptr());    
}
  
int
gzstreambuf::flush_buffer() {
  // Separate the writing of the buffer from overflow() and
  // sync() operation.
  int w = pptr() - pbase();
  if ( gzwrite( file, pbase(), w) != w)
    return EOF;
  pbump( -w);
  return w;
}
  
int
gzstreambuf::overflow( int c) { // used for output buffer only
  if ( ! ( mode & std::ios::out) || ! opened)
    return EOF;
  if (c != EOF) {
    *pptr() = c;
    pbump(1);
  }
  if ( flush_buffer() == EOF)
    return EOF;
  return c;
}
  
int
gzstreambuf::sync() {
  // Changed to use flush_buffer() instead of overflow( EOF)
  // which caused improper behavior with std::endl and flush(),
  // bug reported by Vincent Ricard.
  if ( pptr() && pptr() > pbase()) {
    if ( flush_buffer() == EOF)
      return -1;
  }
  return 0;
}
  
  
  // --------------------------------------
  // class gzstreambase:
// --------------------------------------

gzstreambase::gzstreambase( const char* name, int mode)
{
  init( &buf);
  open( name, mode);
}
  
  gzstreambase::~gzstreambase()
  {
    buf.close();
  }
  
  void
  gzstreambase::open( const char* name, int open_mode) {
    if ( ! buf.open( name, open_mode))
      clear( rdstate() | std::ios::badbit);
}

void gzstreambase::close() {
    if ( buf.is_open())
        if ( ! buf.close())
            clear( rdstate() | std::ios::badbit);
}

#ifdef GZSTREAM_NAMESPACE
} // namespace GZSTREAM_NAMESPACE
#endif

// ============================================================================
// EOF //