abstract base class for input streams. More...

Inheritance diagram for DcmInputStream:

Public Member Functions
virtual	~DcmInputStream ()
	destructor

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

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

virtual OFBool	eos ()
	returns true if the producer is at the end of stream. More...

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

virtual offile_off_t	read (void *buf, offile_off_t buflen)
	reads as many bytes as possible into the given block. More...

virtual offile_off_t	skip (offile_off_t skiplen)
	skips over the given number of bytes (or less) More...

virtual offile_off_t	tell () const
	returns the total number of bytes read from the stream so far More...

virtual OFCondition	installCompressionFilter (E_StreamCompression filterType)
	installs a compression filter for the given stream compression type, which should be neither ESC_none nor ESC_unsupported. More...

virtual DcmInputStreamFactory *	newFactory () const =0
	creates a new factory object for the current stream and stream position. More...

virtual void	mark ()
	marks the current stream position for a later putback operation, overwriting a possibly existing prior putback mark. More...

virtual void	putback ()
	resets the stream to the position previously marked with setPutbackMark(). More...

Protected Member Functions
	DcmInputStream (DcmProducer *initial)
	protected constructor, to be called from derived class constructor More...

const DcmProducer *	currentProducer () const
	returns pointer to current producer object

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

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

Private Attributes
DcmProducer *	current_
	pointer to first node in filter chain

DcmInputFilter *	compressionFilter_
	pointer to compression filter, NULL if no compression

offile_off_t	tell_
	counter for number of bytes read so far

offile_off_t	mark_
	putback marker

Detailed Description

abstract base class for input streams.

Constructor & Destructor Documentation

◆ DcmInputStream()

DcmInputStream::DcmInputStream ( DcmProducer * initial )

protected

protected constructor, to be called from derived class constructor

Parameters

initial initial pointer to first node in filter chain The pointer is not dereferenced in the constructor, so the object pointed to may be initialized later in the subclass constructor.

Member Function Documentation

◆ avail()

virtual offile_off_t DcmInputStream::avail ( )

virtual

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

The DcmObject read 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 read "en bloc", i.e. all or nothing.

Returns: minimum of data available in producer

◆ eos()

virtual OFBool DcmInputStream::eos ( )

virtual

returns true if the producer is at the end of stream.

Returns: true if end of stream, false otherwise

◆ good()

virtual OFBool DcmInputStream::good ( ) const

virtual

returns the status of the stream.

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

Returns: status, true if good

◆ installCompressionFilter()

virtual OFCondition DcmInputStream::installCompressionFilter ( E_StreamCompression filterType )

virtual

installs a compression filter for the given stream compression type, which should be neither ESC_none nor ESC_unsupported.

Once a compression filter is active, it cannot be deactivated or replaced during the lifetime of the stream.

Parameters

filterType type of compression filter

Returns: EC_Normal if successful, an error code otherwise

◆ mark()

virtual void DcmInputStream::mark ( )

virtual

marks the current stream position for a later putback operation, overwriting a possibly existing prior putback mark.

The DcmObject read methods rely on the possibility to putback up to 132 bytes for transfer syntax detection, parse error recovery etc. Implementations of this class should guarantee a putback capability of at least 1 kbyte.

◆ newFactory()

virtual DcmInputStreamFactory* DcmInputStream::newFactory ( ) const

pure virtual

creates a new factory object for the current stream and stream position.

When activated, the factory will be able to create new DcmInputStream delivering the same data as the current stream. Used to defer loading of value fields until accessed. If no factory object can be created (e.g. because the stream is not seekable), returns NULL.

Returns: pointer to new factory object if successful, NULL otherwise.

Implemented in DcmInputFileStream, and DcmInputBufferStream.

◆ putback()

virtual void DcmInputStream::putback ( )

virtual

resets the stream to the position previously marked with setPutbackMark().

If the putback operation fails (no putback mark set or putback buffer exceeded), status of the producer switches to bad.

◆ read()

virtual offile_off_t DcmInputStream::read	(	void *	buf,
		offile_off_t	buflen
	)

virtual

reads as many bytes as possible into the given block.

Parameters

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

Returns: number of bytes actually read.

◆ skip()

virtual offile_off_t DcmInputStream::skip ( offile_off_t skiplen )

virtual

skips over the given number of bytes (or less)

Parameters

skiplen number of bytes to skip

Returns: number of bytes actually skipped.

◆ status()

virtual OFCondition DcmInputStream::status ( ) const

virtual

returns the status of the stream as an OFCondition object.

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

Returns: status, EC_Normal if good

◆ tell()

virtual offile_off_t DcmInputStream::tell ( ) const

virtual

returns the total number of bytes read from the stream so far

Returns: total number of bytes read from the stream

Referenced by DcmFileCache::init().

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

dcmdata/include/dcmtk/dcmdata/dcistrma.h

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ DcmInputStream()

Member Function Documentation

◆ avail()

◆ eos()

◆ good()

◆ installCompressionFilter()

◆ mark()

◆ newFactory()

◆ putback()

◆ read()

◆ skip()

◆ status()

◆ tell()