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/*
Copyright (C) 2016-2020, Dirk Krause
SPDX-License-Identifier: BSD-3-Clause
*/

/*
	WARNING: This file was generated by the dkct program (see
	http://dktools.sourceforge.net/ for details).
	Changes you make here will be lost if dkct is run again!
	You should modify the original source and run dkct on it.
	Original source: dk4strmco.ctr
*/

#ifndef DK4STRMCO_H_INCLUDED
/** Avoid multiple inclusions. */
#define DK4STRMCO_H_INCLUDED 1


#line 9 "dk4strmco.ctr"

/**	@file	dk4strmco.h	Compression streams.

A compression stream is an additional dk4_stream_t object on top of
an existring stream (referred to as downside stream).

Data written to the compression stream is compressed using one or multiple
algorithms:

- Run-length encoding as preprocessing.
- Flate compression or LZW compression.
- ASCII-Hex or ASCII-85 output encoding.

The results of the compression operations are passed to the downside stream.

Note: Closing the compression stream does not close the downside stream.

So you create a mixed stream (i.e. for PDF files) containing both plain
text and compressed chunks. To add a compressed chunk open a compression
stream on top of the existing output stream, pass data to the compression
stream, close the compression stream and continue writing to the output
stream.

*/

#ifndef	DK4CONF_H_INCLUDED
#if DK4_BUILDING_DKTOOLS4
#include "dk4conf.h"
#else
#include <dktools-4/dk4conf.h>
#endif
#endif

#ifndef	DK4ERROR_H_INCLUDED
#if DK4_BUILDING_DKTOOLS4
#include "dk4error.h"
#else
#include <dktools-4/dk4error.h>
#endif
#endif

#ifndef	DK4STRM_H_INCLUDED
#if DK4_BUILDING_DKTOOLS4
#include "dk4strm.h"
#else
#include <dktools-4/dk4strm.h>
#endif
#endif


/**	Preprocessing before compression.
*/
enum dk4_strmco_pp {
	DK4_STRMCO_PP_NONE	= 0 ,	/**< No preprocessing. */
	DK4_STRMCO_PP_RUNLENGTH		/**< Use run-length before real compression. */
};


/**	Compression method.
*/
enum dk4_strmco_co {
	DK4_STRMCO_CO_NONE	= 0 ,	/**< No compression. */
	DK4_STRMCO_CO_FLATE	,		/**< Use flate compression. */
	DK4_STRMCO_CO_LZW			/**< Use LZW compression for PS level 2. */
};


/**	Output encoding.
*/
enum dk4_strmco_oe {
	DK4_STRMCO_OE_NONE	= 0 ,	/**< No output encoding. */
	DK4_STRMCO_OE_HEX ,			/**< Hexadecimal encoding. */
	DK4_STRMCO_OE_ASCII85		/**< ASCII85 encoding. */
};


/**	Flags for compression stream.
*/
enum {
	DK4_STRMCO_FL_EOD_PP	= 1 ,	/**< Write EOD marker at end of preproc. */
	DK4_STRMCO_FL_EOD_OE	= 2 ,	/**< Write EOD marker at end of out enc. */
	DK4_STRMCO_FL_NL_OE		= 4 ,	/**< Break output lines before 80. */
	DK4_STRMCO_FL_CR_NL		= 8 ,	/**< Use CR/NL combination. */
	DK4_STRMCO_FL_UPPER_OE	= 16 ,	/**< Upper case characters in hex digits. */
};


#ifdef	__cplusplus
extern "C" {
#endif

/**	Open a compressing stream on top of an existing stream.
	Only write operations can be performed on the new stream, no
	read operations.
	@param	strm	Low-level destination stream, must be writable.
	@param	pp		Preprocessing method.
	@param	co		Compression method.
	@param	oe		Output encoding.
	@param	fl		Flags.
	@param	erp		Error report, may be NULL.
	@return	Valid pointer to new stream on success, NULL on error.

	Error codes:
	- DK4_E_INVALID_ARGUMENTS<br>
	  if strm is NULL,
	- DK4_E_MATH_OVERFLOW<br>
	  on numeric overflow when calculating the product of elsize and nelem,
	- DK4_E_MEMORY_ALLOCATION_FAILED<br>
	  with mem.elsize and mem.nelem set if there is not enough memory
	  available.
*/
dk4_stream_t *
dk4strmco_open(
	dk4_stream_t		*strm,
	enum dk4_strmco_pp	 pp,
	enum dk4_strmco_co	 co,
	enum dk4_strmco_oe	 oe,
	int					 fl,
	dk4_er_t			*erp
);

#ifdef	__cplusplus
}
#endif


/* vim: set ai sw=4 ts=4 : */

#endif