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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
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