dkof(3) - Linux man page

Name

dkof - output filtering

Synopsis

#include <dkof.h>

dk_stream_t *
dkof_open (dk_stream_t *target, size_t nof);

void
dkof_close (dk_stream_t *str);

int
dkof_set (dk_stream_t *str, size_t n, int what);

int
dkof_start_chunk (dk_stream_t *str);

int
dkof_end_chunk (dk_stream_t *str);

void
dkof_set_crnl (dk_stream_t *str, int v);

Description

Some file formats - i.e. Postscript and PDF - mix plain text and compressed chunks.

Output filters are intended to create the compressed chunks.

The dkof module creates a new dk_stream_t for compression and encoding which writes output to an existing dk_stream_t.

The dkof_open() function creates such a new stream. The nof parameter is the number of filters to apply. The function returns a valid pointer on success, NULL on error.

The dkof_set() function sets a filter cell n to a specified method what. Filter cell n-1 is applied first, 0 is the last cell before writing the output. The following filter cell types can be used:

• DK_OF_TYPE_FLATE

Flate compression from the zlib library.

• ASCII85-encoding

ASCII-85-Encoding.

• DK_OF_TYPE_BUFFERED

Output data is collected to write 512-byte buffers instead of single bytes.

Each stream created by dkof_open() must be closed after usage by the dkof_close() function.

The dkof_set_crnl() function can be used to set up UNIX style line ends (v=0) or Windows style line ends (v=1).

Before writing a compressed chunk the stream must be initialized using dkof_start_chunk().

After writing all chunk data the dkof_end_chunk() function must be used to flush all buffers.

Author

Dirk Krause

Copyright And License

Copyright © 2001-2008, Dirk Krause All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the following
  disclaimer in the documentation and/or other materials
  provided with the distribution.

* Neither the name of the Dirk Krause nor the names of
  contributors may be used to endorse or promote products
  derived from this software without specific prior written
  permission.