DcmWriteCache Class Reference

This class implements a buffering mechanism that is used when writing large elements that reside in file into an output stream. More...

Public Member Functions
	DcmWriteCache ()
	default constructor. Construction is cheap (no allocation of memory block).
	~DcmWriteCache ()
	destructor
void	init (void *owner, Uint32 fieldLength, Uint32 bytesTransferred, E_ByteOrder byteOrder)
	initialize the buffer maintained by this class. More...
OFBool	bufferIsEmpty () const
	check whether the buffer is currently empty More...
Uint32	contentLength () const
	return the number of bytes of user data currently in buffer More...
OFCondition	fillBuffer (DcmElement &elem)
	fill buffer from given DICOM element if buffer is currently empty. More...
Uint32	writeBuffer (DcmOutputStream &outStream)
	write buffer content to output stream More...

Private Member Functions
	DcmWriteCache (const DcmWriteCache &arg)
	private undefined copy constructor
DcmWriteCache &	operator= (const DcmWriteCache &arg)
	private undefined copy assignment operator

Private Attributes
DcmFileCache	fcache_
	file cache object
Uint8 *	buf_
	write buffer
void *	owner_
	current "owner" (DcmElement instance using this buffer)
Uint32	offset_
	offset within buffer to first byte
Uint32	numBytes_
	number of user data bytes currently in buffer
Uint32	capacity_
	buffer size in bytes
Uint32	fieldLength_
	length of the current DICOM element, in bytes
Uint32	fieldOffset_
	offset within the current DICOM element, in bytes
E_ByteOrder	byteOrder_
	current output byte order

Detailed Description

This class implements a buffering mechanism that is used when writing large elements that reside in file into an output stream.

DcmElement::getPartialValue is used to fill the buffer maintained by this class, and the buffer content is then copied to the output stream. The intermediate buffer is necessary because both DcmElement::getPartialValue and DcmOutputStream::write expect a buffer to write to and read from, respectively.

Member Function Documentation

bufferIsEmpty()

OFBool DcmWriteCache::bufferIsEmpty ( ) const

inline

check whether the buffer is currently empty

Returns

true if buffer is empty, false otherwise

contentLength()

Uint32 DcmWriteCache::contentLength ( ) const

inline

return the number of bytes of user data currently in buffer

Returns

number of bytes of user data currently in buffer

fillBuffer()

OFCondition DcmWriteCache::fillBuffer

(

DcmElement &

elem

)

fill buffer from given DICOM element if buffer is currently empty.

This method uses DcmElement::getPartialValue to fill the buffer from the given DICOM element at the given offset (which is updated to reflect the number of bytes read into the buffer).

Parameters

elem	DICOM element to read from

Returns

EC_Normal if successful, an error code otherwise

init()

void DcmWriteCache::init	(	void *	owner,
		Uint32	fieldLength,
		Uint32	bytesTransferred,
		E_ByteOrder	byteOrder
	)

initialize the buffer maintained by this class.

Can safely be called multiple times.

Parameters

owner	current "owner" (DcmElement instance using this buffer)
fieldLength	number of bytes of user data in DICOM element
bytesTransferred	number of bytes of user data in DICOM element that have already been transferred
byteOrder	byteOrder desired byte order in buffer

writeBuffer()

Uint32 DcmWriteCache::writeBuffer

(

DcmOutputStream &

outStream

)

write buffer content to output stream

Parameters

outStream

output stream to write to

Returns

number of bytes written

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

• dcmdata/include/dcmtk/dcmdata/dcwcache.h