gzstream.h
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// ============================================================================
// 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: 2007/07/31 20:09:14 $
// 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>
#ifdef GZSTREAM_NAMESPACE
namespace GZSTREAM_NAMESPACE {
#endif
// ----------------------------------------------------------------------------
// Internal classes to implement gzstream. See below for user classes.
// ----------------------------------------------------------------------------
class gzstreambuf : public std::streambuf {
private:
static const int bufferSize = 47+256; // size of data buff
// totals 512 bytes under g++ for igzstream at the end.
gzFile file; // file handle for compressed file
char buffer[bufferSize]; // data buffer
char opened; // open/close state of stream
int mode; // I/O 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
}
int is_open() { 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; }
};
// ----------------------------------------------------------------------------
// 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 std::istream {
public:
igzstream() : std::istream( &buf) {}
igzstream( const char* name, int open_mode = std::ios::in)
: gzstreambase( name, open_mode), std::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 std::ostream {
public:
ogzstream() : std::ostream( &buf) {}
ogzstream( const char* name, int mode = std::ios::out)
: gzstreambase( name, 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 //