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