/* Copyright (C) 1993, 1995 Aladdin Enterprises.  All rights reserved.
  
  This file is part of Aladdin Ghostscript.
  
  Aladdin Ghostscript is distributed with NO WARRANTY OF ANY KIND.  No author
  or distributor accepts any responsibility for the consequences of using it,
  or for whether it serves any particular purpose or works at all, unless he
  or she says so in writing.  Refer to the Aladdin Ghostscript Free Public
  License (the "License") for full details.
  
  Every copy of Aladdin Ghostscript must include a copy of the License,
  normally in a plain ASCII text file named PUBLIC.  The License grants you
  the right to copy, modify and redistribute Aladdin Ghostscript, but only
  under certain conditions described in the License.  Among other things, the
  License requires that the copyright notice and this notice be preserved on
  all copies.
*/

/* zfilter.c */
/* Filter creation */
#include "memory_.h"
#include "ghost.h"
#include "errors.h"
#include "oper.h"
#include "gsstruct.h"
#include "ialloc.h"
#include "idict.h"
#include "idparam.h"
#include "stream.h"
#include "strimpl.h"
#include "sfilter.h"
#include "srlx.h"
#include "ifilter.h"
#include "files.h"		/* for filter_open, file_d'_buffer_size */

/* Define whether we are including some non-standard filters for testing. */
#define TEST

/* <source> ASCIIHexEncode/filter <file> */
private int
zAXE(os_ptr op)
{	return filter_write(op, 0, &s_AXE_template, NULL, 0);
}

/* <target> ASCIIHexDecode/filter <file> */
private int
zAXD(os_ptr op)
{	return filter_read(op, 0, &s_AXD_template, NULL, 0);
}

/* <target> NullEncode/filter <file> */
private int
zNullE(os_ptr op)
{	return filter_write(op, 0, &s_NullE_template, NULL, 0);
}

/* <source> <bool> PFBDecode/filter <file> */
private int
zPFBD(os_ptr op)
{	stream_PFBD_state state;
	check_type(*op, t_boolean);
	state.binary_to_hex = op->value.boolval;
	return filter_read(op, 1, &s_PFBD_template, (stream_state *)&state, 0);
}

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

/* Common setup for RLE and RLD filters. */
private int
rl_setup(os_ptr op, bool *eod)
{	if ( r_has_type(op, t_dictionary) )
	  {	int code;
		check_dict_read(*op);
		if ( (code = dict_bool_param(op, "EndOfData", true, eod)) < 0 )
		  return code;
		return 1;
	  }
	else
	  {	*eod = true;
		return 0;
	  }
}

/* <target> <record_size> RunLengthEncode/filter <file> */
/* <target> <record_size> <dict> RunLengthEncode/filter <file> */
private int
zRLE(register os_ptr op)
{	stream_RLE_state state;
	int code = rl_setup(op, &state.EndOfData);
	if ( code < 0 )
	  return code;
	check_int_leu(*op, max_uint);
	state.record_size = op->value.intval;
	return filter_write(op, 1 + code, &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, code, &s_RLD_template, (stream_state *)&state, 0);
}

/* <source> <EODcount> <EODstring> SubFileDecode/filter <file> */
private int
zSFD(os_ptr op)
{	stream_SFD_state state;
	check_type(op[-1], t_integer);
	check_read_type(*op, t_string);
	if ( op[-1].value.intval < 0 )
	  return_error(e_rangecheck);
	state.count = op[-1].value.intval;
	state.eod.data = op->value.const_bytes;
	state.eod.size = r_size(op);
	return filter_read(op, 2, &s_SFD_template, (stream_state *)&state,
			   r_space(op));
}

#ifdef TEST

#include "store.h"

/* <size> BigStringEncode/filter <file> */
private int BSE_close(P1(stream *));
private int
zBSE(os_ptr op)
{	stream *s;
	byte *data;
	long len;

	check_type(op[-0], t_integer);
	len = op[-0].value.intval;
	if ( len < 0 )
	  return_error(e_rangecheck);

	data = ialloc_string(len, "BigStringEncode(string)");
	if ( !data )
	  return_error(e_VMerror);
	s = file_alloc_stream(imemory, "BigStringEncode(stream)");
	if ( !s )
	  {	ifree_string(data, len, "BigStringEncode(string)");
		return_error(e_VMerror);
	  }
	swrite_string(s, data, len);
	s->is_temp = 0;
	s->read_id = 0;
	s->procs.close = BSE_close;
	s->save_close = BSE_close;
	make_file(op,
		  ((a_write | a_execute) | icurrent_space),
		  s->write_id,
		  s);
	return 0;
}
private int
BSE_close(stream *s)
{	return 0;
}

#endif				/* TEST */

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

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

/* Set up an input filter. */
const stream_procs s_new_read_procs =
{	s_std_noavailable, s_std_noseek, s_std_read_reset,
	s_std_read_flush, s_filter_close
};
int
filter_read(os_ptr op, int npop, const stream_template *template,
  stream_state *st, uint space)
{	uint min_size = template->min_out_size;
	uint save_space = ialloc_space(idmemory);
	register os_ptr sop = op - npop;
	stream *s;
	stream *sstrm;
	int code;

	/* 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_new_read_procs, template, st);
	if ( code < 0 )
	  goto out;
	s = fptr(sop);
	s->strm = sstrm;
	pop(npop);
out:	ialloc_set_space(idmemory, save_space);
	return code;
}

/* Set up an output filter. */
const stream_procs s_new_write_procs =
{	s_std_noavailable, s_std_noseek, s_std_write_reset,
	s_std_write_flush, s_filter_close
};
int
filter_write(os_ptr op, int npop, const stream_template *template,
  stream_state *st, uint space)
{	uint min_size = template->min_in_size;
	uint save_space = ialloc_space(idmemory);
	register os_ptr sop = op - npop;
	stream *s;
	stream *sstrm;
	int code;

	/* 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_new_write_procs, template, st);
	if ( code < 0 )
	  goto out;
	s = fptr(sop);
	s->strm = sstrm;
	pop(npop);
out:	ialloc_set_space(idmemory, save_space);
	return code;
}

/* 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_size, bool writing)
{	stream *s = *ps;
	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_new_write_procs,
				     &s_NullE_template, NULL);
		else
		  code = filter_open("r", min_size, &bsop, &s_new_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;
	  }
}

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

BEGIN_OP_DEFS(zfilter_op_defs) {
		/* We enter SubFileDecode (only) as a separate operator. */
	{"3.subfiledecode", zSFD},
		op_def_begin_filter(),
	{"1ASCIIHexEncode", zAXE},
	{"1ASCIIHexDecode", zAXD},
	{"1NullEncode", zNullE},
	{"2PFBDecode", zPFBD},
	{"2RunLengthEncode", zRLE},
	{"1RunLengthDecode", zRLD},
	{"3SubFileDecode", zSFD},
#ifdef TEST
	{"1BigStringEncode", zBSE},
#endif
END_OP_DEFS(0) }
