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InflatingStream.cpp

//
// InflatingStream.cpp
//
// $Id: //poco/1.2/Foundation/src/InflatingStream.cpp#1 $
//
// Library: Foundation
// Package: Streams
// Module:  ZLibStream
//
// 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.
//


#include "Poco/InflatingStream.h"
#include "Poco/Exception.h"


namespace Poco {


InflatingStreamBuf::InflatingStreamBuf(std::istream& istr, StreamType type): 
      BufferedStreamBuf(STREAM_BUFFER_SIZE, std::ios::in),
      _pIstr(&istr),
      _pOstr(0),
      _eof(false)
{
      _zstr.zalloc    = Z_NULL;
      _zstr.zfree     = Z_NULL;
      _zstr.opaque    = Z_NULL;
      _zstr.next_in   = 0;
      _zstr.avail_in  = 0;
      _zstr.next_out  = 0;
      _zstr.avail_out = 0;

      int rc = inflateInit2(&_zstr, 15 + (type == STREAM_GZIP ? 16 : 0));
      if (rc != Z_OK) throw IOException(zError(rc)); 

      _buffer = new char[INFLATE_BUFFER_SIZE];
}


InflatingStreamBuf::InflatingStreamBuf(std::ostream& ostr, StreamType type): 
      BufferedStreamBuf(STREAM_BUFFER_SIZE, std::ios::out),
      _pIstr(0),
      _pOstr(&ostr),
      _eof(false)
{
      _zstr.zalloc    = Z_NULL;
      _zstr.zfree     = Z_NULL;
      _zstr.opaque    = Z_NULL;
      _zstr.next_in   = 0;
      _zstr.avail_in  = 0;
      _zstr.next_out  = 0;
      _zstr.avail_out = 0;

      int rc = inflateInit2(&_zstr, 15 + (type == STREAM_GZIP ? 16 : 0));
      if (rc != Z_OK) throw IOException(zError(rc));

      _buffer = new char[INFLATE_BUFFER_SIZE];
}


InflatingStreamBuf::~InflatingStreamBuf()
{
      try
      {
            close();
      }
      catch (...)
      {
      }
      delete [] _buffer;
}


int InflatingStreamBuf::close()
{
      sync();
      if (_pIstr || _pOstr)
      {
            int rc = inflateEnd(&_zstr);
            if (rc != Z_OK) throw IOException(zError(rc));
            _pIstr = 0;
            _pOstr = 0;
      }
      return 0;
}


int InflatingStreamBuf::readFromDevice(char* buffer, std::streamsize length)
{
      if (_eof || !_pIstr) return 0;

      if (_zstr.avail_in == 0)
      {
            int n = 0;
            if (_pIstr->good())
            {
                  _pIstr->read(_buffer, INFLATE_BUFFER_SIZE);
                  n = _pIstr->gcount();
            }
            if (n == 0) return 0;
            _zstr.next_in   = (unsigned char*) _buffer;
            _zstr.avail_in  = n;
      }
      _zstr.next_out  = (unsigned char*) buffer;
      _zstr.avail_out = length;
      for (;;)
      {
            int rc = inflate(&_zstr, Z_NO_FLUSH);
            if (rc == Z_STREAM_END)
            {
                  _eof = true;
                  return length - _zstr.avail_out;
            }
            if (rc != Z_OK) throw IOException(zError(rc));
            if (_zstr.avail_out == 0)
                  return length;
            if (_zstr.avail_in == 0)
            {
                  int n = 0;
                  if (_pIstr->good())
                  {
                        _pIstr->read(_buffer, INFLATE_BUFFER_SIZE);
                        n = _pIstr->gcount();
                  }
                  if (n > 0)
                  {
                        _zstr.next_in  = (unsigned char*) _buffer;
                        _zstr.avail_in = n;
                  }
            }
      }
}


int InflatingStreamBuf::writeToDevice(const char* buffer, std::streamsize length)
{
      if (length == 0 || !_pOstr) return 0;
      
      _zstr.next_in   = (unsigned char*) buffer;
      _zstr.avail_in  = length;
      _zstr.next_out  = (unsigned char*) _buffer;
      _zstr.avail_out = INFLATE_BUFFER_SIZE;
      for (;;)
      {
            int rc = inflate(&_zstr, Z_NO_FLUSH);
            if (rc == Z_STREAM_END)
            {
                  _pOstr->write(_buffer, INFLATE_BUFFER_SIZE - _zstr.avail_out);
                  if (!_pOstr->good()) throw IOException(zError(rc));
                  break;
            }
            if (rc != Z_OK) throw IOException(zError(rc)); 
            if (_zstr.avail_out == 0)
            {
                  _pOstr->write(_buffer, INFLATE_BUFFER_SIZE);
                  if (!_pOstr->good()) throw IOException(zError(rc));
                  _zstr.next_out  = (unsigned char*) _buffer;
                  _zstr.avail_out = INFLATE_BUFFER_SIZE;
            }
            if (_zstr.avail_in == 0)
            {
                  _pOstr->write(_buffer, INFLATE_BUFFER_SIZE - _zstr.avail_out);
                  if (!_pOstr->good()) throw IOException(zError(rc)); 
                  _zstr.next_out  = (unsigned char*) _buffer;
                  _zstr.avail_out = INFLATE_BUFFER_SIZE;
                  break;
            }
      }
      return length;
}


InflatingIOS::InflatingIOS(std::ostream& ostr, InflatingStreamBuf::StreamType type):
      _buf(ostr, type)
{
      poco_ios_init(&_buf);
}


InflatingIOS::InflatingIOS(std::istream& istr, InflatingStreamBuf::StreamType type):
      _buf(istr, type)
{
      poco_ios_init(&_buf);
}


InflatingIOS::~InflatingIOS()
{
}


InflatingStreamBuf* InflatingIOS::rdbuf()
{
      return &_buf;
}


InflatingOutputStream::InflatingOutputStream(std::ostream& ostr, InflatingStreamBuf::StreamType type):
      InflatingIOS(ostr, type),
      std::ostream(&_buf)
{
}


InflatingOutputStream::~InflatingOutputStream()
{
}


int InflatingOutputStream::close()
{
      return _buf.close();
}


InflatingInputStream::InflatingInputStream(std::istream& istr, InflatingStreamBuf::StreamType type):
      InflatingIOS(istr, type),
      std::istream(&_buf)
{
}


InflatingInputStream::~InflatingInputStream()
{
}


} // namespace Poco

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