zlib compression filter for output streams More...

Inheritance diagram for DcmZLibOutputFilter:

Public Member Functions
	DcmZLibOutputFilter ()
	default constructor

virtual	~DcmZLibOutputFilter ()
	destructor

virtual OFBool	good () const
	returns the status of the consumer. More...

virtual OFCondition	status () const
	returns the status of the consumer as an OFCondition object. More...

virtual OFBool	isFlushed () const
	returns true if the consumer is flushed, i.e. More...

virtual offile_off_t	avail () const
	returns the minimum number of bytes that can be written with the next call to write(). More...

virtual offile_off_t	write (const void *buf, offile_off_t buflen)
	processes as many bytes as possible from the given input block. More...

virtual void	flush ()
	instructs the consumer to flush its internal content until either the consumer becomes "flushed" or I/O suspension occurs. More...

virtual void	append (DcmConsumer &consumer)
	determines the consumer to which the filter is supposed to write it's output. More...

Public Member Functions inherited from DcmOutputFilter
virtual	~DcmOutputFilter ()
	destructor

Public Member Functions inherited from DcmConsumer
virtual	~DcmConsumer ()
	destructor

Private Member Functions
	DcmZLibOutputFilter (const DcmZLibOutputFilter &)
	private unimplemented copy constructor

DcmZLibOutputFilter &	operator= (const DcmZLibOutputFilter &)
	private unimplemented copy assignment operator

void	flushOutputBuffer ()
	writes the content of the output ring buffer to the next filter stage until the output ring buffer becomes empty or the next filter stage becomes full

offile_off_t	compress (const void *buf, offile_off_t buflen, OFBool finalize)
	feed data from the given block of data to the compression codec until complete or the output ring buffer becomes full. More...

offile_off_t	fillInputBuffer (const void *buf, offile_off_t buflen)
	copies as much of the given block of data as possible in the input ring buffer More...

void	compressInputBuffer (OFBool finalize)
	feed data from the input ring buffer to the compression codec until complete or the output ring buffer becomes full. More...

Private Attributes
DcmConsumer *	current_
	pointer to consumer to which compressed output is written

z_streamp	zstream_
	pointer to struct z_stream object containing the zlib status

OFCondition	status_
	status

OFBool	flushed_
	true if the zlib object has reported Z_STREAM_END

unsigned char *	inputBuf_
	input ring buffer

offile_off_t	inputBufStart_
	offset of first byte in input ring buffer

offile_off_t	inputBufCount_
	number of bytes in input ring buffer

unsigned char *	outputBuf_
	output ring buffer

offile_off_t	outputBufStart_
	offset of first byte in output ring buffer

offile_off_t	outputBufCount_
	number of bytes in output ring buffer

Detailed Description

zlib compression filter for output streams

Member Function Documentation

◆ append()

virtual void DcmZLibOutputFilter::append ( DcmConsumer & consumer )

virtual

determines the consumer to which the filter is supposed to write it's output.

Once a consumer for the output filter has been defined, it cannot be changed anymore during the lifetime of the object.

Parameters

consumer reference to consumer, must not be circular chain

Implements DcmOutputFilter.

◆ avail()

virtual offile_off_t DcmZLibOutputFilter::avail ( ) const

virtual

returns the minimum number of bytes that can be written with the next call to write().

The DcmObject write methods rely on avail to return a value > 0 if there is no I/O suspension since certain data such as tag and length are only written "en bloc", i.e. all or nothing.

Returns: minimum of space available in consumer

Implements DcmConsumer.

◆ compress()

offile_off_t DcmZLibOutputFilter::compress	(	const void *	buf,
		offile_off_t	buflen,
		OFBool	finalize
	)

private

feed data from the given block of data to the compression codec until complete or the output ring buffer becomes full.

Does not flush the output ring buffer.

Parameters

buf	pointer to input data
buflen	number of bytes in buf
finalize	true if the current block of data constitutes the end of the input stream, i.e. the compression codec should be forced to flush its internal state.

Returns: number of bytes processed

◆ compressInputBuffer()

void DcmZLibOutputFilter::compressInputBuffer ( OFBool finalize )

private

feed data from the input ring buffer to the compression codec until complete or the output ring buffer becomes full.

Does not flush the output ring buffer.

Parameters

finalize true if the content of the input ring buffer constitutes the end of the input stream, i.e. the compression codec should be forced to flush its internal state.

◆ fillInputBuffer()

offile_off_t DcmZLibOutputFilter::fillInputBuffer	(	const void *	buf,
		offile_off_t	buflen
	)

private

copies as much of the given block of data as possible in the input ring buffer

Parameters

buf	pointer to input data
buflen	number of bytes in buf

Returns: number of bytes copied to input ring buffer

◆ flush()

virtual void DcmZLibOutputFilter::flush ( )

virtual

instructs the consumer to flush its internal content until either the consumer becomes "flushed" or I/O suspension occurs.

After a call to flush(), a call to write() will produce undefined behaviour.

Implements DcmConsumer.

◆ good()

virtual OFBool DcmZLibOutputFilter::good ( ) const

virtual

returns the status of the consumer.

Unless the status is good, the consumer will not permit any operation.

Returns: status, true if good

Implements DcmConsumer.

◆ isFlushed()

virtual OFBool DcmZLibOutputFilter::isFlushed ( ) const

virtual

returns true if the consumer is flushed, i.e.

has no more data pending in it's internal state that needs to be flushed before the stream is closed.

Returns: true if consumer is flushed, false otherwise

Implements DcmConsumer.

◆ status()

virtual OFCondition DcmZLibOutputFilter::status ( ) const

virtual

returns the status of the consumer as an OFCondition object.

Unless the status is good, the consumer will not permit any operation.

Returns: status, EC_Normal if good

Implements DcmConsumer.

◆ write()

virtual offile_off_t DcmZLibOutputFilter::write	(	const void *	buf,
		offile_off_t	buflen
	)

virtual

processes as many bytes as possible from the given input block.

Parameters

buf	pointer to memory block, must not be NULL
buflen	length of memory block

Returns: number of bytes actually processed.

Implements DcmConsumer.

The documentation for this class was generated from the following file:

dcmdata/include/dcmtk/dcmdata/dcostrmz.h

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Function Documentation

◆ append()

◆ avail()

◆ compress()

◆ compressInputBuffer()

◆ fillInputBuffer()

◆ flush()

◆ good()

◆ isFlushed()

◆ status()

◆ write()