DeflateOutputStreambuf is an output stream filter, that deflates the data that is written to it before it passes it on to the output stream it is attached to. More...

#include <deflateoutputstreambuf.h>

Public Member Functions
bool	closeStream ()

	DeflateOutputStreambuf (streambuf *outbuf, bool user_init=false, bool del_outbuf=false)
	DeflateOutputStreambuf constructor. More...

uint32	getCount () const
	Returns the number of bytes written to the streambuf, that has been processed from the input buffer by the compressor. More...

uint32	getCrc32 () const
	Returns the CRC32 for the current stream. More...

bool	init (int comp_level=6)

virtual	~DeflateOutputStreambuf ()
	Destructor. More...

Public Member Functions inherited from zipios::FilterOutputStreambuf
	FilterOutputStreambuf (streambuf *outbuf, bool del_outbuf=false)
	Constructor. More...

virtual	~FilterOutputStreambuf ()
	Destructor. More...

Protected Member Functions
void	endDeflation ()
	Flushes the remaining data in the zlib buffers, after which the only possible operations are deflateEnd() or deflateReset(). More...

bool	flushOutvec ()
	Flushes _outvec and updates _zs.next_out and _zs.avail_out. More...

virtual int	overflow (int c=EOF)

virtual int	sync ()

Detailed Description

DeflateOutputStreambuf is an output stream filter, that deflates the data that is written to it before it passes it on to the output stream it is attached to.

Deflation/Inflation is a compression/decompression method used in gzip and zip. The zlib library is used to perform the actual deflation, this class only wraps the functionality in an output stream filter.

Constructor & Destructor Documentation

◆ DeflateOutputStreambuf()

zipios::DeflateOutputStreambuf::DeflateOutputStreambuf	(	streambuf *	outbuf,
		bool	user_init = `false`,
		bool	del_outbuf = `false`
	)

explicit

DeflateOutputStreambuf constructor.

Parameters

outbuf	the streambuf to use for output.
user_init	If false user must invoke init() before writing any data. (ZipOutputStreambuf needs to do this)
del_outbuf	if true is specified outbuf will be deleted, when the DeflateOutputStreambuf is destructed.

References init().

◆ ~DeflateOutputStreambuf()

zipios::DeflateOutputStreambuf::~DeflateOutputStreambuf ( )

virtual

Destructor.

References closeStream().

Member Function Documentation

◆ closeStream()

bool zipios::DeflateOutputStreambuf::closeStream ( )

References endDeflation().

Referenced by zipios::ZipOutputStreambuf::closeEntry(), zipios::GZIPOutputStreambuf::finish(), and ~DeflateOutputStreambuf().

◆ endDeflation()

void zipios::DeflateOutputStreambuf::endDeflation ( )

protected

Flushes the remaining data in the zlib buffers, after which the only possible operations are deflateEnd() or deflateReset().

References flushOutvec(), and overflow().

Referenced by closeStream(), and init().

◆ flushOutvec()

bool zipios::DeflateOutputStreambuf::flushOutvec ( )

protected

Flushes _outvec and updates _zs.next_out and _zs.avail_out.

Referenced by endDeflation(), and overflow().

◆ getCount()

uint32 zipios::DeflateOutputStreambuf::getCount ( ) const

Returns the number of bytes written to the streambuf, that has been processed from the input buffer by the compressor.

After closeStream() has been called this number is the total number of bytes written to the stream.

Referenced by zipios::ZipOutputStreambuf::updateEntryHeaderInfo().

◆ getCrc32()

uint32 zipios::DeflateOutputStreambuf::getCrc32 ( ) const

Returns the CRC32 for the current stream.

The returned value is the CRC for the data that has been compressed already (due to a call to overflow()). As DeflateOutputStreambuf may buffer an arbitrary amount of bytes until closeStream() has been invoked, the returned value is not very useful before closeStream() has been called.

Referenced by zipios::ZipOutputStreambuf::updateEntryHeaderInfo().