/* Copyright (C) 1990, 1992, 1993 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.
*/

/* zpacked.c */
/* Packed array operators */
#include "ghost.h"
#include "errors.h"
#include "ialloc.h"
#include "idict.h"
#include "iname.h"
#include "istack.h"		/* for iparray.h */
#include "ipacked.h"
#include "iparray.h"
#include "ivmspace.h"
#include "oper.h"
#include "store.h"

/* Import the array packing flag */
extern ref ref_array_packing;

/* - currentpacking <bool> */
int
zcurrentpacking(register os_ptr op)
{	push(1);
	ref_assign(op, &ref_array_packing);
	return 0;
}

/* <obj_0> ... <obj_n-1> <n> packedarray <packedarray> */
int
zpackedarray(register os_ptr op)
{	int code;
	ref parr;
	check_type(*op, t_integer);
	if ( op->value.intval < 0 ||
	     (op->value.intval > op - osbot &&
	      op->value.intval >= ref_stack_count(&o_stack))
	   )
		return_error(e_rangecheck);
	osp--;
	code = make_packed_array(&parr, &o_stack, (uint)op->value.intval,
				 "packedarray");
	osp++;
	if ( code >= 0 )
	  *osp = parr;
	return code;
}

/* <bool> setpacking - */
int
zsetpacking(register os_ptr op)
{	check_type(*op, t_boolean);
	ref_assign_old(NULL, &ref_array_packing, op, "setpacking");
	pop(1);
	return 0;
}

/* ------ Non-operator routines ------ */

/* Make a packed array.  See the comment in packed.h about */
/* ensuring that refs in mixed arrays are properly aligned. */
int
make_packed_array(ref *parr, ref_stack *pstack, uint size, client_name_t cname)
{	uint i;
	const ref *pref;
	uint idest = 0, ishort = 0;
	ref_packed *pbody, *pdest;
	ref_packed *pshort;		/* points to start of */
					/* last run of short elements */
	uint local = ialloc_local_attr(idmemory);
	int skip = 0, pad;
	ref rtemp;
	int code;

	/* Do a first pass to calculate the size of the array, */
	/* and to detect local-into-global stores. */

	for ( i = size; i != 0; i-- )
	{	pref = ref_stack_index(pstack, i - 1);
		switch ( r_btype(pref) )  /* not r_type, opers are special */
		{
		case t_name:
			if ( name_index(pref) >= packed_name_max_index )
				break;	/* can't pack */
			idest++;
			continue;
		case t_integer:
			if ( pref->value.intval < packed_min_intval ||
			     pref->value.intval > packed_max_intval
			   )
				break;
			idest++;
			continue;
		case t_oparray:
		case t_operator:
		{	uint oidx;
			if ( !r_has_attr(pref, a_executable) )
				break;
			oidx = op_index(pref);
			if ( oidx == 0 || oidx > packed_int_mask )
				break;
		}	idest++;
			continue;
		default:
			/* Check for local-into-global store. */
			if ( !local && r_is_local(pref) )
				return_error(e_invalidaccess);
		}
		/* Can't pack this element, use a full ref. */
		/* We may have to unpack up to align_packed_per_ref - 1 */
		/* preceding short elements. */
		/* If we are at the beginning of the array, however, */
		/* we can just move the elements up. */
		{	int i = (idest - ishort) & (align_packed_per_ref - 1);
			if ( ishort == 0 )		/* first time */
			  idest += skip = -i & (align_packed_per_ref - 1);
			else
			  idest += (packed_per_ref - 1) * i;
		}
		ishort = idest += packed_per_ref;
	}
	pad = -idest & (packed_per_ref - 1);	/* padding at end */

	/* Now we can allocate the array. */

	code = ialloc_ref_array(&rtemp, 0, (idest + pad) / packed_per_ref,
				cname);
	if ( code < 0 )
	  return code;
	pbody = (ref_packed *)rtemp.value.refs;

	/* Make sure any initial skipped elements contain legal packed */
	/* refs, so that the garbage collector can scan storage. */

	pshort = pbody;
	for ( ; skip; skip-- )
		*pbody++ = pt_tag(pt_integer);
	pdest = pbody;

	for ( i = size; i != 0; i-- )
	{	pref = ref_stack_index(pstack, i - 1);
		switch ( r_btype(pref) )	/* not r_type, opers are special */
		{
		case t_name:
		{	uint nidx = name_index(pref);
			if ( nidx >= packed_name_max_index )
				break;	/* can't pack */
			*pdest++ = nidx +
			  (r_has_attr(pref, a_executable) ?
			   pt_tag(pt_executable_name) :
			   pt_tag(pt_literal_name));
		}	continue;
		case t_integer:
			if ( pref->value.intval < packed_min_intval ||
			     pref->value.intval > packed_max_intval
			   )
				break;
			*pdest++ = pt_tag(pt_integer) +
			  ((short)pref->value.intval - packed_min_intval);
			continue;
		case t_oparray:
		case t_operator:
		{	uint oidx;
			if ( !r_has_attr(pref, a_executable) )
				break;
			oidx = op_index(pref);
			if ( oidx == 0 || oidx > packed_int_mask )
				break;
			*pdest++ = pt_tag(pt_executable_operator) + oidx;
		}	continue;
		}
		/* Can't pack this element, use a full ref. */
		/* We may have to unpack up to align_packed_per_ref - 1 */
		/* preceding short elements. */
		/* Note that if we are at the beginning of the array, */
		/* 'skip' already ensures that we don't need to do this. */
		{	int i = (pdest - pshort) & (align_packed_per_ref - 1);
			const ref_packed *psrc = pdest;
			ref *pmove =
			  (ref *)(pdest += (packed_per_ref - 1) * i);
			ref_assign_new(pmove, pref);
			while ( --i >= 0 )
			{	--psrc;
				--pmove;
				packed_get(psrc, pmove);
			}
		}
		pshort = pdest += packed_per_ref;
	}

	{	int atype =
		  (pdest == pbody + size ? t_shortarray : t_mixedarray);

		/* Pad with legal packed refs so that the garbage collector */
		/* can scan storage. */

		for ( ; pad; pad-- )
			*pdest++ = pt_tag(pt_integer);

		/* Finally, make the array. */

		ref_stack_pop(pstack, size);
		make_tasv_new(parr, atype, a_readonly | local, size,
			      packed, pbody + skip);
	}
	return 0;
}

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

op_def zpacked_op_defs[] = {
	{"0currentpacking", zcurrentpacking},
	{"1packedarray", zpackedarray},
	{"1setpacking", zsetpacking},
	op_def_end(0)
};
