zlib compression filter for input streams More...
Inheritance diagram for DcmZLibInputFilter:
Public Member Functions | |
| DcmZLibInputFilter () | |
| default constructor | |
| virtual | ~DcmZLibInputFilter () |
| 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 | append (DcmProducer &producer) |
| determines the producer from which the filter is supposed to read it's input. | |
Private Member Functions | |
| DcmZLibInputFilter (const DcmZLibInputFilter &) | |
| private unimplemented copy constructor | |
| DcmZLibInputFilter & | operator= (const DcmZLibInputFilter &) |
| private unimplemented copy assignment operator | |
| offile_off_t | fillInputBuffer () |
| reads data from the producer into the input ring buffer until the input ring buffer becomes full or the producer suspends | |
| offile_off_t | decompress (const void *buf, offile_off_t buflen) |
| decompress data into the given output block until complete or no more input is available in the input ring buffer. | |
| void | fillOutputBuffer () |
| reads and decompresses data from the producer until the producer suspends or the output ring buffer becomes full. | |
| 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 | fillInputBuffer (const void *buf, offile_off_t buflen) |
| copies as much of the given block of data as possible in the input ring buffer | |
| void | compressInputBuffer (OFBool finalize) |
| feed data from the input ring buffer to the compression codec until complete or the output ring buffer becomes full. | |
Private Attributes | |
| DcmProducer * | current_ |
| pointer to producer from which compressed input is read | |
| z_streamp | zstream_ |
| pointer to struct z_stream object containing the zlib status | |
| OFCondition | status_ |
| status | |
| OFBool | eos_ |
| 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 available for read in output ring buffer | |
| offile_off_t | outputBufPutback_ |
| number of putback bytes in output ring buffer | |
| OFBool | padded_ |
| flag indicating whether or not a pad byte has been appended to the input stream | |
Detailed Description
zlib compression filter for input streams
Member Function Documentation
| virtual void DcmZLibInputFilter::append | ( | DcmProducer & | producer | ) | [virtual] |
determines the producer from which the filter is supposed to read it's input.
Once a producer for the input filter has been defined, it cannot be changed anymore during the lifetime of the object.
- Parameters:
-
producer reference to producer, must not be circular chain
Implements DcmInputFilter.
| virtual offile_off_t DcmZLibInputFilter::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.
| void DcmZLibInputFilter::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.
| offile_off_t DcmZLibInputFilter::decompress | ( | const void * | buf, |
| offile_off_t | buflen | ||
| ) | [private] |
decompress data into the given output block until complete or no more input is available in the input ring buffer.
does not re-fill the input ring buffer from the producer.
- Parameters:
-
buf pointer to input data buflen number of bytes in buf
- Returns:
- number of bytes processed
| virtual OFBool DcmZLibInputFilter::eos | ( | ) | [virtual] |
returns true if the producer is at the end of stream.
- Returns:
- true if end of stream, false otherwise
Implements DcmProducer.
| offile_off_t DcmZLibInputFilter::fillInputBuffer | ( | ) | [private] |
reads data from the producer into the input ring buffer until the input ring buffer becomes full or the producer suspends
- Returns:
- number of bytes added to input buffer
| offile_off_t DcmZLibInputFilter::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
| virtual OFBool DcmZLibInputFilter::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.
| virtual void DcmZLibInputFilter::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.
| virtual offile_off_t DcmZLibInputFilter::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.
| virtual offile_off_t DcmZLibInputFilter::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.
| virtual OFCondition DcmZLibInputFilter::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/dcistrmz.h