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//
// DeflatingStream.h
//
// Library: Foundation
// Package: Streams
// Module: ZLibStream
//
// Definition of the DeflatingStream class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_DeflatingStream_INCLUDED
#define Foundation_DeflatingStream_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/BufferedStreamBuf.h"
#include <istream>
#include <ostream>
#if defined(POCO_UNBUNDLED)
#include <zlib.h>
#else
#error #include "Poco/zlib.h"
#endif
namespace Poco {
class Foundation_API DeflatingStreamBuf: public BufferedStreamBuf
/// This is the streambuf class used by DeflatingInputStream and DeflatingOutputStream.
/// 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 compression.
/// A compression level (0 to 9) can be specified in the constructor.
{
public:
enum StreamType
{
STREAM_ZLIB, /// Create a zlib header, use Adler-32 checksum.
STREAM_GZIP /// Create a gzip header, use CRC-32 checksum.
};
DeflatingStreamBuf(std::istream& istr, StreamType type, int level);
/// Creates a DeflatingStreamBuf for compressing data read
/// from the given input stream.
DeflatingStreamBuf(std::istream& istr, int windowBits, int level);
/// Creates a DeflatingStreamBuf for compressing data read
/// from the given input stream.
///
/// Please refer to the zlib documentation of deflateInit2() for a description
/// of the windowBits parameter.
DeflatingStreamBuf(std::ostream& ostr, StreamType type, int level);
/// Creates a DeflatingStreamBuf for compressing data passed
/// through and forwarding it to the given output stream.
DeflatingStreamBuf(std::ostream& ostr, int windowBits, int level);
/// Creates a DeflatingStreamBuf for compressing data passed
/// through and forwarding it to the given output stream.
///
/// Please refer to the zlib documentation of deflateInit2() for a description
/// of the windowBits parameter.
~DeflatingStreamBuf();
/// Destroys the DeflatingStreamBuf.
int close();
/// Finishes up the stream.
///
/// Must be called when deflating to an output stream.
protected:
int readFromDevice(char* buffer, std::streamsize length);
int writeToDevice(const char* buffer, std::streamsize length);
virtual int sync();
private:
enum
{
STREAM_BUFFER_SIZE = 1024,
DEFLATE_BUFFER_SIZE = 32768
};
std::istream* _pIstr;
std::ostream* _pOstr;
char* _buffer;
z_stream _zstr;
bool _eof;
};
class Foundation_API DeflatingIOS: public virtual std::ios
/// The base class for DeflatingOutputStream and DeflatingInputStream.
///
/// This class is needed to ensure the correct initialization
/// order of the stream buffer and base classes.
{
public:
DeflatingIOS(std::ostream& ostr, DeflatingStreamBuf::StreamType type = DeflatingStreamBuf::STREAM_ZLIB, int level = Z_DEFAULT_COMPRESSION);
/// Creates a DeflatingIOS for compressing data passed
/// through and forwarding it to the given output stream.
DeflatingIOS(std::ostream& ostr, int windowBits, int level);
/// Creates a DeflatingIOS for compressing data passed
/// through and forwarding it to the given output stream.
///
/// Please refer to the zlib documentation of deflateInit2() for a description
/// of the windowBits parameter.
DeflatingIOS(std::istream& istr, DeflatingStreamBuf::StreamType type = DeflatingStreamBuf::STREAM_ZLIB, int level = Z_DEFAULT_COMPRESSION);
/// Creates a DeflatingIOS for compressing data read
/// from the given input stream.
DeflatingIOS(std::istream& istr, int windowBits, int level);
/// Creates a DeflatingIOS for compressing data read
/// from the given input stream.
///
/// Please refer to the zlib documentation of deflateInit2() for a description
/// of the windowBits parameter.
~DeflatingIOS();
/// Destroys the DeflatingIOS.
DeflatingStreamBuf* rdbuf();
/// Returns a pointer to the underlying stream buffer.
protected:
DeflatingStreamBuf _buf;
};
class Foundation_API DeflatingOutputStream: public std::ostream, public DeflatingIOS
/// This stream compresses all data passing through it
/// using zlib's deflate algorithm.
/// After all data has been written to the stream, close()
/// must be called to ensure completion of compression.
/// Example:
/// std::ofstream ostr("data.gz", std::ios::binary);
/// DeflatingOutputStream deflater(ostr, DeflatingStreamBuf::STREAM_GZIP);
/// deflater << "Hello, world!" << std::endl;
/// deflater.close();
/// ostr.close();
{
public:
DeflatingOutputStream(std::ostream& ostr, DeflatingStreamBuf::StreamType type = DeflatingStreamBuf::STREAM_ZLIB, int level = Z_DEFAULT_COMPRESSION);
/// Creates a DeflatingOutputStream for compressing data passed
/// through and forwarding it to the given output stream.
DeflatingOutputStream(std::ostream& ostr, int windowBits, int level);
/// Creates a DeflatingOutputStream for compressing data passed
/// through and forwarding it to the given output stream.
///
/// Please refer to the zlib documentation of deflateInit2() for a description
/// of the windowBits parameter.
~DeflatingOutputStream();
/// Destroys the DeflatingOutputStream.
int close();
/// Finishes up the stream.
///
/// Must be called when deflating to an output stream.
protected:
virtual int sync();
};
class Foundation_API DeflatingInputStream: public std::istream, public DeflatingIOS
/// This stream compresses all data passing through it
/// using zlib's deflate algorithm.
{
public:
DeflatingInputStream(std::istream& istr, DeflatingStreamBuf::StreamType type = DeflatingStreamBuf::STREAM_ZLIB, int level = Z_DEFAULT_COMPRESSION);
/// Creates a DeflatingIOS for compressing data read
/// from the given input stream.
DeflatingInputStream(std::istream& istr, int windowBits, int level);
/// Creates a DeflatingIOS for compressing data read
/// from the given input stream.
///
/// Please refer to the zlib documentation of deflateInit2() for a description
/// of the windowBits parameter.
~DeflatingInputStream();
/// Destroys the DeflatingInputStream.
};
} // namespace Poco
#endif // Foundation_DeflatingStream_INCLUDED
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