/* Copyright (C) 1993, 1995, 1996, 1998 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.
  
  Aladdin Enterprises supports the work of the GNU Project, but is not
  affiliated with the Free Software Foundation or the GNU Project.  GNU
  Ghostscript, as distributed by Aladdin Enterprises, does not require any
  GNU software to build or run it.
*/

/*$Id: zfilter.c $ */
/* Filter creation */
#include "memory_.h"
#include "ghost.h"
#include "oper.h"
#include "gsstruct.h"
#include "ialloc.h"
#include "idict.h"
#include "idparam.h"
#include "ilevel.h"		/* SubFileDecode is different in LL3 */
#include "stream.h"
#include "strimpl.h"
#include "sfilter.h"
#include "srlx.h"
#include "sstring.h"
#include "ifilter.h"
#include "files.h"		/* for filter_open, file_d'_buffer_size */

/* <source> ASCIIHexEncode/filter <file> */
/* <source> <dict> ASCIIHexEncode/filter <file> */
private int
zAXE(os_ptr op)
{
    return filter_write_simple(op, &s_AXE_template);
}

/* <target> ASCIIHexDecode/filter <file> */
/* <target> <dict> ASCIIHexDecode/filter <file> */
private int
zAXD(os_ptr op)
{
    return filter_read_simple(op, &s_AXD_template);
}

/* <target> NullEncode/filter <file> */
/* <target> <dict_ignored> NullEncode/filter <file> */
private int
zNullE(os_ptr op)
{
    return filter_write_simple(op, &s_NullE_template);
}

/* <source> <bool> PFBDecode/filter <file> */
/* <source> <dict> <bool> PFBDecode/filter <file> */
private int
zPFBD(os_ptr op)
{
    stream_PFBD_state state;
    os_ptr sop = op;

    check_type(*sop, t_boolean);
    state.binary_to_hex = sop->value.boolval;
    return filter_read(op, 1, &s_PFBD_template, (stream_state *) & state, 0);
}

/* <target> PSStringEncode/filter <file> */
/* <target> <dict> PSStringEncode/filter <file> */
private int
zPSSE(os_ptr op)
{
    return filter_write_simple(op, &s_PSSE_template);
}

/* ------ RunLength filters ------ */

/* Common setup for RLE and RLD filters. */
private int
rl_setup(os_ptr dop, bool * eod)
{
    if (r_has_type(dop, t_dictionary)) {
	int code;

	check_dict_read(*dop);
	if ((code = dict_bool_param(dop, "EndOfData", true, eod)) < 0)
	    return code;
	return 1;
    } else {
	*eod = true;
	return 0;
    }
}

/* <target> <record_size> RunLengthEncode/filter <file> */
/* <target> <dict> <record_size> RunLengthEncode/filter <file> */
private int
zRLE(register os_ptr op)
{
    stream_RLE_state state;
    int code;

    check_op(2);
    code = rl_setup(op - 1, &state.EndOfData);
    if (code < 0)
	return code;
    check_int_leu(*op, max_uint);
    state.record_size = op->value.intval;
    return filter_write(op, 1, &s_RLE_template, (stream_state *) & state, 0);
}

/* <source> RunLengthDecode/filter <file> */
/* <source> <dict> RunLengthDecode/filter <file> */
private int
zRLD(os_ptr op)
{
    stream_RLD_state state;
    int code = rl_setup(op, &state.EndOfData);

    if (code < 0)
	return code;
    return filter_read(op, 0, &s_RLD_template, (stream_state *) & state, 0);
}

/* <source> <EODcount> <EODstring> SubFileDecode/filter <file> */
/* <source> <dict> <EODcount> <EODstring> SubFileDecode/filter <file> */
/* <source> <dict> SubFileDecode/filter <file> *//* (LL3 only) */
private int
zSFD(os_ptr op)
{
    stream_SFD_state state;
    ref *sop = op;
    int npop;

    if (LL3_ENABLED && r_has_type(op, t_dictionary)) {
	int count;
	int code;

	check_dict_read(*op);
	if ((code = dict_int_param(op, "EODCount", 0, max_int, -1, &count)) < 0)
	    return code;
	if (dict_find_string(op, "EODString", &sop) <= 0)
	    return_error(e_rangecheck);
	state.count = count;
	npop = 0;
    } else {
	check_type(sop[-1], t_integer);
	if (sop[-1].value.intval < 0)
	    return_error(e_rangecheck);
	state.count = sop[-1].value.intval;
	npop = 2;
    }
    check_read_type(*sop, t_string);
    state.eod.data = sop->value.const_bytes;
    state.eod.size = r_size(sop);
    return filter_read(op, npop, &s_SFD_template, (stream_state *) & state,
		       r_space(sop));
}

/* ------ Utilities ------ */

/* Forward references */
private int filter_ensure_buf(P3(stream **, uint, bool));

/* Set up an input filter. */
int
filter_read(os_ptr op, int npop, const stream_template * template,
	    stream_state * st, uint space)
{
    uint min_size = template->min_out_size + max_min_left;
    uint save_space = ialloc_space(idmemory);
    os_ptr sop = op - npop;
    stream *s;
    stream *sstrm;
    bool close = false;
    int code;

    /* Skip over an optional dictionary parameter. */
    if (r_has_type(sop, t_dictionary)) {
	check_dict_read(*sop);
	if ((code = dict_bool_param(sop, "CloseSource", false, &close)) < 0)
	    return code;
	--sop;
    }
    /*
     * Check to make sure that the underlying data
     * can function as a source for reading.
     */
    switch (r_type(sop)) {
	case t_string:
	    check_read(*sop);
	    ialloc_set_space(idmemory, max(space, r_space(sop)));
	    sstrm = file_alloc_stream(imemory, "filter_read(string stream)");
	    if (sstrm == 0) {
		code = gs_note_error(e_VMerror);
		goto out;
	    }
	    sread_string(sstrm, sop->value.bytes, r_size(sop));
	    sstrm->is_temp = 1;
	    break;
	case t_file:
	    check_read_known_file(sstrm, sop, return);
	    ialloc_set_space(idmemory, max(space, r_space(sop)));
	    goto ens;
	default:
	    check_proc(*sop);
	    ialloc_set_space(idmemory, max(space, r_space(sop)));
	    code = sread_proc(sop, &sstrm);
	    if (code < 0)
		goto out;
	    sstrm->is_temp = 2;
	  ens:
	    code = filter_ensure_buf(&sstrm,
				     template->min_in_size +
				     sstrm->state->template->min_out_size,
				     false);
	    if (code < 0)
		goto out;
	    break;
    }
    if (min_size < 128)
	min_size = file_default_buffer_size;
    code = filter_open("r", min_size, (ref *) sop,
		       &s_filter_read_procs, template, st);
    if (code < 0)
	goto out;
    s = fptr(sop);
    s->strm = sstrm;
    s->close_strm = close;
    pop(op - sop);
out:
    ialloc_set_space(idmemory, save_space);
    return code;
}
int
filter_read_simple(os_ptr op, const stream_template * template)
{
    return filter_read(op, 0, template, NULL, 0);
}

/* Set up an output filter. */
int
filter_write(os_ptr op, int npop, const stream_template * template,
	     stream_state * st, uint space)
{
    uint min_size = template->min_in_size + max_min_left;
    uint save_space = ialloc_space(idmemory);
    register os_ptr sop = op - npop;
    stream *s;
    stream *sstrm;
    bool close = false;
    int code;

    /* Skip over an optional dictionary parameter. */
    if (r_has_type(sop, t_dictionary)) {
	check_dict_read(*sop);
	if ((code = dict_bool_param(sop, "CloseTarget", false, &close)) < 0)
	    return code;
	--sop;
    }
    /*
     * Check to make sure that the underlying data
     * can function as a sink for writing.
     */
    switch (r_type(sop)) {
	case t_string:
	    check_write(*sop);
	    ialloc_set_space(idmemory, max(space, r_space(sop)));
	    sstrm = file_alloc_stream(imemory, "filter_write(string)");
	    if (sstrm == 0) {
		code = gs_note_error(e_VMerror);
		goto out;
	    }
	    swrite_string(sstrm, sop->value.bytes, r_size(sop));
	    sstrm->is_temp = 1;
	    break;
	case t_file:
	    check_write_known_file(sstrm, sop, return);
	    ialloc_set_space(idmemory, max(space, r_space(sop)));
	    goto ens;
	default:
	    check_proc(*sop);
	    ialloc_set_space(idmemory, max(space, r_space(sop)));
	    code = swrite_proc(sop, &sstrm);
	    if (code < 0)
		goto out;
	    sstrm->is_temp = 2;
	  ens:
	    code = filter_ensure_buf(&sstrm,
				     template->min_out_size +
				     sstrm->state->template->min_in_size,
				     true);
	    if (code < 0)
		goto out;
	    break;
    }
    if (min_size < 128)
	min_size = file_default_buffer_size;
    code = filter_open("w", min_size, (ref *) sop,
		       &s_filter_write_procs, template, st);
    if (code < 0)
	goto out;
    s = fptr(sop);
    s->strm = sstrm;
    s->close_strm = close;
    pop(op - sop);
out:
    ialloc_set_space(idmemory, save_space);
    return code;
}
int
filter_write_simple(os_ptr op, const stream_template * template)
{
    return filter_write(op, 0, template, NULL, 0);
}

/* Define a byte-at-a-time NullDecode filter for intermediate buffers. */
/* (The standard NullDecode filter can read ahead too far.) */
private int
s_Null1D_process(stream_state * st, stream_cursor_read * pr,
		 stream_cursor_write * pw, bool last)
{
    if (pr->ptr >= pr->limit)
	return 0;
    if (pw->ptr >= pw->limit)
	return 1;
    *++(pw->ptr) = *++(pr->ptr);
    return 1;
}
private const stream_template s_Null1D_template =
{
    &st_stream_state, NULL, s_Null1D_process, 1, 1
};

/* Ensure a minimum buffer size for a filter. */
/* This may require creating an intermediate stream. */
private int
filter_ensure_buf(stream ** ps, uint min_buf_size, bool writing)
{
    stream *s = *ps;
    uint min_size = min_buf_size + max_min_left;
    stream *bs;
    ref bsop;
    int code;

    if (s->modes == 0 /* stream is closed */  || s->bsize >= min_size)
	return 0;
    /* Otherwise, allocate an intermediate stream. */
    if (s->cbuf == 0) {
	/* This is a newly created procedure stream. */
	/* Just allocate a buffer for it. */
	uint len = max(min_size, 128);
	byte *buf = ialloc_bytes(len, "filter_ensure_buf");

	if (buf == 0)
	    return_error(e_VMerror);
	s->cbuf = buf;
	s->srptr = s->srlimit = s->swptr = buf - 1;
	s->swlimit = buf - 1 + len;
	s->bsize = s->cbsize = len;
	return 0;
    } else {
	/* Allocate an intermediate stream. */
	if (writing)
	    code = filter_open("w", min_size, &bsop, &s_filter_write_procs,
			       &s_NullE_template, NULL);
	else
	    code = filter_open("r", min_size, &bsop, &s_filter_read_procs,
			       &s_Null1D_template, NULL);
	if (code < 0)
	    return code;
	bs = fptr(&bsop);
	bs->strm = s;
	bs->is_temp = 2;
	*ps = bs;
	return code;
    }
}

/* Mark a (filter) stream as temporary. */
/* We define this here to avoid importing stream.h into zf*.c. */
void
filter_mark_temp(const ref * fop, int is_temp)
{
    fptr(fop)->is_temp = is_temp;
}

/* ------ Initialization procedure ------ */

const op_def zfilter_op_defs[] =
{
		/* We enter PSStringEncode and SubFileDecode (only) */
		/* as separate operators. */
    {"1.psstringencode", zPSSE},
    {"2.subfiledecode", zSFD},
    op_def_begin_filter(),
    {"1ASCIIHexEncode", zAXE},
    {"1ASCIIHexDecode", zAXD},
    {"1NullEncode", zNullE},
    {"2PFBDecode", zPFBD},
    {"1PSStringEncode", zPSSE},
    {"2RunLengthEncode", zRLE},
    {"1RunLengthDecode", zRLD},
    {"3SubFileDecode", zSFD},
    op_def_end(0)
};
