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#include <Filter.h>
Public Types | |
enum | ReferencePos { e_begin = SEEK_SET, e_end = SEEK_END, e_cur = SEEK_CUR } |
Provides the fields that represent reference points in streams for seeking. More... | |
Public Member Functions | |
Filter () | |
~Filter () | |
Filter (const Filter ©) | |
Filter & | operator= (const Filter &other) |
operator bool () | |
void | AttachFilter (Filter attach_filter) |
Attaches a filter to the this filter. | |
Filter | ReleaseAttachedFilter () |
Release the ownership of the attached filter. | |
Filter | GetAttachedFilter () |
Filter | GetSourceFilter () |
const char * | GetName () const |
const char * | GetDecodeName () const |
UChar * | Begin () |
size_t | Size () |
void | Consume (size_t num_bytes) |
Moves the Begin() pointer num_bytes forward. | |
size_t | Count () |
size_t | SetCount (size_t new_count) |
Sets a new counting point for the current filter. | |
void | SetStreamLength (size_t bytes) |
The functions specifies the length of the data stream. | |
void | Flush () |
Forces any data remaining in the buffer to be written to input or output filter. | |
void | FlushAll () |
Forces any data remaining in the filter chain to the source or destination. | |
bool | IsInputFilter () |
bool | CanSeek () |
void | Seek (ptrdiff_t offset, ReferencePos origin) |
When overridden in a derived class, sets the position within the current stream. | |
ptrdiff_t | Tell () |
Reports the current read position in the stream relative to the stream origin. | |
Filter | CreateInputIterator () |
Create Filter iterator. | |
const UString | GetFilePath () const |
A Filter is the abstract base class of all filters. A filter is an abstraction of a sequence of bytes, such as a file, an input/output device, an inter-process communication pipe, or a TCP/IP socket. The Filter class and its derived classes provide a generic view of these different types of input and output, isolating the programmer from the specific details of the operating system and the underlying devices.
Besides providing access to input/output sources Filters can be also to transform the data (e.g. to compress the data stream, to normalize the image data, to encrypt data, etc). Filters can also be attached to each other to form pipelines. For example, a filter used to open an image data file can be attached to a filter that decompresses the data, which is attached to another filter that will normalize the image data.
Depending on the underlying data source or repository, filters might support only some of these capabilities. An application can query a stream for its capabilities by using the IsInputFilter() and CanSeek() properties.
StdFile file("my_stream.txt", StdFile::e_read_mode); FilterReader reader(file); while (reader.Read(..)) ...
pdftron::Filters::Filter::Filter | ( | ) |
pdftron::Filters::Filter::~Filter | ( | ) |
pdftron::Filters::Filter::Filter | ( | const Filter & | copy | ) |
pdftron::Filters::Filter::operator bool | ( | ) | [inline] |
void pdftron::Filters::Filter::AttachFilter | ( | Filter | attach_filter | ) |
Attaches a filter to the this filter.
If this filter owns another filter it will be deleted. This filter then becomes the owner of the attached filter.
Filter pdftron::Filters::Filter::ReleaseAttachedFilter | ( | ) |
Release the ownership of the attached filter.
After the attached filter is released this filter points to NULL filter.
Filter pdftron::Filters::Filter::GetAttachedFilter | ( | ) |
Filter pdftron::Filters::Filter::GetSourceFilter | ( | ) |
const char* pdftron::Filters::Filter::GetName | ( | ) | const |
const char* pdftron::Filters::Filter::GetDecodeName | ( | ) | const |
UChar* pdftron::Filters::Filter::Begin | ( | ) |
size_t pdftron::Filters::Filter::Size | ( | ) |
void pdftron::Filters::Filter::Consume | ( | size_t | num_bytes | ) |
size_t pdftron::Filters::Filter::Count | ( | ) |
size_t pdftron::Filters::Filter::SetCount | ( | size_t | new_count | ) |
Sets a new counting point for the current filter.
All subsequent Consume() operations will increment this counter.
Make sure that the output filter is flushed before using SetCount().
void pdftron::Filters::Filter::SetStreamLength | ( | size_t | bytes | ) |
The functions specifies the length of the data stream.
The default implementation doesn't do anything. For some derived filters such as file segment filter it may be useful to override this function in order to limit the stream length.
- | the length of stream in bytes |
void pdftron::Filters::Filter::Flush | ( | ) |
Forces any data remaining in the buffer to be written to input or output filter.
void pdftron::Filters::Filter::FlushAll | ( | ) |
Forces any data remaining in the filter chain to the source or destination.
bool pdftron::Filters::Filter::IsInputFilter | ( | ) |
bool pdftron::Filters::Filter::CanSeek | ( | ) |
void pdftron::Filters::Filter::Seek | ( | ptrdiff_t | offset, | |
ReferencePos | origin | |||
) |
When overridden in a derived class, sets the position within the current stream.
offset | - A byte offset relative to origin. If offset is negative, the new position will precede the position specified by origin by the number of bytes specified by offset. If offset is zero, the new position will be the position specified by origin. If offset is positive, the new position will follow the position specified by origin by the number of bytes specified by offset. | |
origin | - A value of type ReferencePos indicating the reference point used to obtain the new position |
- | throws FilterExc if the method is not implemented in derived class |
ptrdiff_t pdftron::Filters::Filter::Tell | ( | ) |
Reports the current read position in the stream relative to the stream origin.
- | throws FilterExc if the method is not implemented in derived class |
Filter pdftron::Filters::Filter::CreateInputIterator | ( | ) |
Create Filter iterator.
Filter iterator similar to a regular filter. However, there can be only one owner of the attached filter.
- | throws an exception if the method is not implemented in the derived class |
const UString pdftron::Filters::Filter::GetFilePath | ( | ) | const |