DCMTK: DcmBufferProducer Class Reference

DCMTK Version 3.6.9 OFFIS DICOM Toolkit

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Public Member Functions | Private Member Functions | Private Attributes | List of all members
DcmBufferProducer Class Reference

producer class that reads data from a buffer provided by the caller. More...

Inheritance diagram for DcmBufferProducer:

## Public Member Functions
| DcmBufferProducer ()
| constructor
virtual | ~DcmBufferProducer ()
| destructor
virtual OFBool | good () const
| returns the status of the producer.
virtual OFCondition | status () const
| returns the status of the producer as an OFCondition object.
virtual OFBool | eos ()
| returns true if the producer is at the end of stream.
virtual offile_off_t | avail ()
| returns the minimum number of bytes that can be read with the next call to read().
virtual offile_off_t | read (void *buf, offile_off_t buflen)
| reads as many bytes as possible into the given block.
virtual offile_off_t | skip (offile_off_t skiplen)
| skips over the given number of bytes (or less)
virtual void | putback (offile_off_t num)
| resets the stream to the position by the given number of bytes.
virtual void | setBuffer (const void *buf, offile_off_t buflen)
| adds the content of the given buffer to the input stream.
virtual void | releaseBuffer ()
| releases the current buffer.
virtual void | setEos ()
| marks the end of stream, i.e.
Public Member Functions inherited from DcmProducer
virtual | ~DcmProducer ()
| destructor

## Private Member Functions
| DcmBufferProducer (const DcmBufferProducer &)
| private unimplemented copy constructor
DcmBufferProducer & | operator= (const DcmBufferProducer &)
| private unimplemented copy assignment operator

## Private Attributes
unsigned char * | buffer_
| the user buffer we're actually reading from
unsigned char * | backup_
| the backup buffer
offile_off_t | bufSize_
| size of the user buffer, in bytes
offile_off_t | bufIndex_
| number of bytes read from the user buffer
offile_off_t | backupIndex_
| number of bytes read from the backup buffer
offile_off_t | backupStart_
| index of first valid byte in backup buffer, for putback
OFCondition | status_
| status
OFBool | eosflag_
| true if setEos has been called before

## Detailed Description

producer class that reads data from a buffer provided by the caller.

Used for DICOM network communication.

## Member Function Documentation

## ◆ avail()

virtual offile_off_t DcmBufferProducer::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

Implements DcmProducer.

## ◆ eos()

virtual OFBool DcmBufferProducer::eos | ( |  | ) |
| virtual

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

Returns
  true if end of stream, false otherwise

Implements DcmProducer.

## ◆ good()

virtual OFBool DcmBufferProducer::good | ( |  | ) | const
| virtual

returns the status of the producer.

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

Returns
  status, true if good

Implements DcmProducer.

## ◆ putback()

virtual void DcmBufferProducer::putback | ( | offile_off_t | num | ) |
| virtual

resets the stream to the position by the given number of bytes.

Parameters

  num | number of bytes to putback. If the putback operation fails, the producer status becomes bad.

Implements DcmProducer.

## ◆ read()

virtual offile_off_t DcmBufferProducer::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.

Implements DcmProducer.

## ◆ releaseBuffer()

virtual void DcmBufferProducer::releaseBuffer | ( |  | ) |
| virtual

releases the current buffer.

Should only be called when the content of the buffer has been read as far as possible. Pending input from the buffer is copied into an internal backup buffer if necessary. If an overflow condition occurs, the producer status becomes bad.

## ◆ setBuffer()

virtual void DcmBufferProducer::setBuffer | ( | const void * | buf,
|  | offile_off_t | buflen )
| virtual

adds the content of the given buffer to the input stream.

Parameters

  buf | buffer from which data is read. Must be allocated by caller and remain valid until releaseBuffer() is called
  buflen | buffer length, must be even number > 0.

## ◆ setEos()

virtual void DcmBufferProducer::setEos | ( |  | ) |
| virtual

marks the end of stream, i.e.

the data provided with the last call to setBuffer is the last data available in the stream.

## ◆ skip()

virtual offile_off_t DcmBufferProducer::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.

Implements DcmProducer.

## ◆ status()

virtual OFCondition DcmBufferProducer::status | ( |  | ) | const
| virtual

returns the status of the producer as an OFCondition object.

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

Returns
  status, EC_Normal if good

Implements DcmProducer.

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

- dcmdata/include/dcmtk/dcmdata/dcistrmb.h

Generated on Wed Apr 30 2025 for DCMTK Version 3.6.9 by Doxygen 1.13.2