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//
// InflatingStream.h
//
// $Id: //poco/1.4/Foundation/include/Poco/InflatingStream.h#2 $
//
// Library: Foundation
// Package: Streams
// Module: ZLibStream
//
// Definition of the InflatingInputStream and InflatingOutputStream classes.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_InflatingStream_INCLUDED
#define Foundation_InflatingStream_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/BufferedStreamBuf.h"
#include <istream>
#include <ostream>
#if defined(POCO_UNBUNDLED)
#include <zlib.h>
#else
#include "Poco/zlib.h"
#endif
namespace Poco {
class Foundation_API InflatingStreamBuf: public BufferedStreamBuf
/// This is the streambuf class used by InflatingInputStream and InflatingOutputStream.
/// The actual work is delegated to zlib (see http://zlib.net).
/// Both zlib (deflate) streams and gzip streams are supported.
/// Output streams should always call close() to ensure
/// proper completion of decompression.
{
public:
enum StreamType
{
STREAM_ZLIB, /// Expect a zlib header, use Adler-32 checksum.
STREAM_GZIP, /// Expect a gzip header, use CRC-32 checksum.
STREAM_ZIP /// STREAM_ZIP is handled as STREAM_ZLIB, except that we do not check the ADLER32 value (must be checked by caller)
};
InflatingStreamBuf(std::istream& istr, StreamType type);
/// Creates an InflatingStreamBuf for expanding the compressed data read from
/// the give input stream.
InflatingStreamBuf(std::istream& istr, int windowBits);
/// Creates an InflatingStreamBuf for expanding the compressed data read from
/// the given input stream.
///
/// Please refer to the zlib documentation of inflateInit2() for a description
/// of the windowBits parameter.
InflatingStreamBuf(std::ostream& ostr, StreamType type);
/// Creates an InflatingStreamBuf for expanding the compressed data passed through
/// and forwarding it to the given output stream.
InflatingStreamBuf(std::ostream& ostr, int windowBits);
/// Creates an InflatingStreamBuf for expanding the compressed data passed through
/// and forwarding it to the given output stream.
///
/// Please refer to the zlib documentation of inflateInit2() for a description
/// of the windowBits parameter.
~InflatingStreamBuf();
/// Destroys the InflatingStreamBuf.
int close();
/// Finishes up the stream.
///
/// Must be called when inflating to an output stream.
void reset();
/// Resets the stream buffer.
protected:
int readFromDevice(char* buffer, std::streamsize length);
int writeToDevice(const char* buffer, std::streamsize length);
int sync();
private:
enum
{
STREAM_BUFFER_SIZE = 1024,
INFLATE_BUFFER_SIZE = 32768
};
std::istream* _pIstr;
std::ostream* _pOstr;
char* _buffer;
z_stream _zstr;
bool _eof;
bool _check;
};
class Foundation_API InflatingIOS: public virtual std::ios
/// The base class for InflatingOutputStream and InflatingInputStream.
///
/// This class is needed to ensure the correct initialization
/// order of the stream buffer and base classes.
{
public:
InflatingIOS(std::ostream& ostr, InflatingStreamBuf::StreamType type = InflatingStreamBuf::STREAM_ZLIB);
/// Creates an InflatingIOS for expanding the compressed data passed through
/// and forwarding it to the given output stream.
InflatingIOS(std::ostream& ostr, int windowBits);
/// Creates an InflatingIOS for expanding the compressed data passed through
/// and forwarding it to the given output stream.
///
/// Please refer to the zlib documentation of inflateInit2() for a description
/// of the windowBits parameter.
InflatingIOS(std::istream& istr, InflatingStreamBuf::StreamType type = InflatingStreamBuf::STREAM_ZLIB);
/// Creates an InflatingIOS for expanding the compressed data read from
/// the given input stream.
InflatingIOS(std::istream& istr, int windowBits);
/// Creates an InflatingIOS for expanding the compressed data read from
/// the given input stream.
///
/// Please refer to the zlib documentation of inflateInit2() for a description
/// of the windowBits parameter.
~InflatingIOS();
/// Destroys the InflatingIOS.
InflatingStreamBuf* rdbuf();
/// Returns a pointer to the underlying stream buffer.
protected:
InflatingStreamBuf _buf;
};
class Foundation_API InflatingOutputStream: public InflatingIOS, public std::ostream
/// This stream decompresses all data passing through it
/// using zlib's inflate algorithm.
///
/// After all data has been written to the stream, close()
/// must be called to ensure completion of decompression.
{
public:
InflatingOutputStream(std::ostream& ostr, InflatingStreamBuf::StreamType type = InflatingStreamBuf::STREAM_ZLIB);
/// Creates an InflatingOutputStream for expanding the compressed data passed through
/// and forwarding it to the given output stream.
InflatingOutputStream(std::ostream& ostr, int windowBits);
/// Creates an InflatingOutputStream for expanding the compressed data passed through
/// and forwarding it to the given output stream.
///
/// Please refer to the zlib documentation of inflateInit2() for a description
/// of the windowBits parameter.
~InflatingOutputStream();
/// Destroys the InflatingOutputStream.
int close();
/// Finishes up the stream.
///
/// Must be called to ensure all data is properly written to
/// the target output stream.
};
class Foundation_API InflatingInputStream: public InflatingIOS, public std::istream
/// This stream decompresses all data passing through it
/// using zlib's inflate algorithm.
/// Example:
/// std::ifstream istr("data.gz", std::ios::binary);
/// InflatingInputStream inflater(istr, InflatingStreamBuf::STREAM_GZIP);
/// std::string data;
/// inflater >> data;
///
/// The underlying input stream can contain more than one gzip/deflate stream.
/// After a gzip/deflate stream has been processed, reset() can be called
/// to inflate the next stream.
{
public:
InflatingInputStream(std::istream& istr, InflatingStreamBuf::StreamType type = InflatingStreamBuf::STREAM_ZLIB);
/// Creates an InflatingInputStream for expanding the compressed data read from
/// the given input stream.
InflatingInputStream(std::istream& istr, int windowBits);
/// Creates an InflatingInputStream for expanding the compressed data read from
/// the given input stream.
///
/// Please refer to the zlib documentation of inflateInit2() for a description
/// of the windowBits parameter.
~InflatingInputStream();
/// Destroys the InflatingInputStream.
void reset();
/// Resets the zlib machinery so that another zlib stream can be read from
/// the same underlying input stream.
};
} // namespace Poco
#endif // Foundation_InflatingStream_INCLUDED
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