vmap/plugins/archivezip/zlibstream.h

/*
   Copyright (C) 2001-2006, William Joseph.
   All Rights Reserved.

   This file is part of GtkRadiant.

   GtkRadiant is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   GtkRadiant 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GtkRadiant; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#if !defined( INCLUDED_ZLIBSTREAM_H )
#define INCLUDED_ZLIBSTREAM_H

#include "zlib.h"
#include "idatastream.h"

/// \brief A wrapper around an InputStream of data compressed with the zlib deflate algorithm.
///
/// - Uses z_stream to decompress the data stream on the fly.
/// - Uses a buffer to reduce the number of times the wrapped stream must be read.
class DeflatedInputStream : public InputStream {
InputStream &m_istream;
z_stream m_zipstream;
enum unnamed0 { m_bufsize = 1024 };
unsigned char m_buffer[m_bufsize];

public:
DeflatedInputStream(InputStream &istream)
	: m_istream(istream)
{
	m_zipstream.zalloc = 0;
	m_zipstream.zfree = 0;
	m_zipstream.opaque = 0;
	m_zipstream.avail_in = 0;
	inflateInit2(&m_zipstream, -MAX_WBITS);
}

~DeflatedInputStream()
{
	inflateEnd(&m_zipstream);
}

size_type read(byte_type *buffer, size_type length)
{
	m_zipstream.next_out = buffer;
	m_zipstream.avail_out = static_cast<uInt>( length );
	while (m_zipstream.avail_out != 0) {
		if (m_zipstream.avail_in == 0) {
			m_zipstream.next_in = m_buffer;
			m_zipstream.avail_in = static_cast<uInt>( m_istream.read(m_buffer, m_bufsize));
		}
		if (inflate(&m_zipstream, Z_SYNC_FLUSH) != Z_OK) {
			break;
		}
	}
	return length - m_zipstream.avail_out;
}
};

#endif