/* Copyright (C) 1991, 2000 Aladdin Enterprises.  All rights reserved.
  
  This file is part of GNU Ghostscript.
  
  GNU Ghostscript is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY.  No author or distributor accepts responsibility
  to anyone for the consequences of using it or for whether it serves any
  particular purpose or works at all, unless he says so in writing.  Refer
  to the GNU General Public License for full details.
  
  Everyone is granted permission to copy, modify and redistribute GNU
  Ghostscript, but only under the conditions described in the GNU General
  Public License.  A copy of this license is supposed to have been given
  to you along with GNU Ghostscript so you can know your rights and
  responsibilities.  It should be in a file named COPYING.  Among other
  things, the copyright notice and this notice must be preserved on all
  copies.
*/

/*$RCSfile: zfilter2.c,v $ $Revision: 1.3.2.1 $ */
/* Additional filter creation */
#include "memory_.h"
#include "ghost.h"
#include "oper.h"
#include "gsstruct.h"
#include "ialloc.h"
#include "idict.h"
#include "idparam.h"
#include "store.h"
#include "strimpl.h"
#include "sfilter.h"
#include "scfx.h"
#include "slzwx.h"
#include "spdiffx.h"
#include "spngpx.h"
#include "ifilter.h"
#include "ifilter2.h"
#include "ifwpred.h"

/* ------ CCITTFaxEncode filter ------ */

/* <target> <dict> CCITTFaxEncode/filter <file> */
private int
zCFE(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    stream_CFE_state cfs;
    int code;

    check_type(*op, t_dictionary);
    check_dict_read(*op);
    code = zcf_setup(op, (stream_CF_state *)&cfs, iimemory);
    if (code < 0)
	return code;
    return filter_write(i_ctx_p, 0, &s_CFE_template, (stream_state *)&cfs, 0);
}

/* ------ Common setup for possibly pixel-oriented encoding filters ------ */

int
filter_write_predictor(i_ctx_t *i_ctx_p, int npop,
		       const stream_template * template, stream_state * st)
{
    os_ptr op = osp;
    int predictor, code;
    stream_PDiff_state pds;
    stream_PNGP_state pps;

    if (r_has_type(op, t_dictionary)) {
	if ((code = dict_int_param(op, "Predictor", 0, 15, 1, &predictor)) < 0)
	    return code;
	switch (predictor) {
	    case 0:		/* identity */
		predictor = 1;
	    case 1:		/* identity */
		break;
	    case 2:		/* componentwise horizontal differencing */
		code = zpd_setup(op, &pds);
		break;
	    case 10:
	    case 11:
	    case 12:
	    case 13:
	    case 14:
	    case 15:
		/* PNG prediction */
		code = zpp_setup(op, &pps);
		break;
	    default:
		return_error(e_rangecheck);
	}
	if (code < 0)
	    return code;
    } else
	predictor = 1;
    if (predictor == 1)
	return filter_write(i_ctx_p, npop, template, st, 0);
    {
	/* We need to cascade filters. */
	ref rtarget, rdict;
	int code;

	/* Save the operands, just in case. */
	ref_assign(&rtarget, op - 1);
	ref_assign(&rdict, op);
	code = filter_write(i_ctx_p, npop, template, st, 0);
	if (code < 0)
	    return code;
	/* filter_write changed osp.... */
	op = osp;
	code =
	    (predictor == 2 ?
	     filter_write(i_ctx_p, 0, &s_PDiffE_template, (stream_state *)&pds, 0) :
	     filter_write(i_ctx_p, 0, &s_PNGPE_template, (stream_state *)&pps, 0));
	if (code < 0) {
	    /* Restore the operands.  Don't bother trying to clean up */
	    /* the first stream. */
	    osp = ++op;
	    ref_assign(op - 1, &rtarget);
	    ref_assign(op, &rdict);
	    return code;
	}
	/*
	 * Mark the compression stream as temporary, and propagate
	 * CloseTarget from it to the predictor stream.
	 */
	filter_mark_strm_temp(op, 2);
	return code;
    }
}

/* ------ LZW encoding filter ------ */

/* <target> LZWEncode/filter <file> */
/* <target> <dict> LZWEncode/filter <file> */
/*
 * Note: the default implementation of this filter, in slzwce.c,
 * does not use any algorithms that could reasonably be claimed
 * to be subject to Unisys' Welch Patent.
 */
private int
zLZWE(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    stream_LZW_state lzs;
    int code = zlz_setup(op, &lzs);

    if (code < 0)
	return code;
    return filter_write_predictor(i_ctx_p, 0, &s_LZWE_template,
				  (stream_state *) & lzs);
}

/* ================ Initialization procedure ================ */

const op_def zfilter2_op_defs[] =
{
    op_def_begin_filter(),
    {"2CCITTFaxEncode", zCFE},
    {"1LZWEncode", zLZWE},
    op_def_end(0)
};
