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InflatingStream.h
//
// 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.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#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 {


00057 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:
00065       enum StreamType
      {
            STREAM_ZLIB, /// Expect a zlib header, use Adler-32 checksum.
00068             STREAM_GZIP, /// Expect a gzip header, use CRC-32 checksum.
00069             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);

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;
};


00125 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:
00161       InflatingStreamBuf _buf;
};


00165 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.
};


00195 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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