/* Copyright (C) 1990, 1992, 1993, 1999 Aladdin Enterprises.  All rights reserved.
  
  This program is free software; you can redistribute it and/or modify it
  under the terms of the GNU General Public License version 2
  as published by the Free Software Foundation.


  This software is provided AS-IS with no warranty, either express or
  implied. That is, this program is distributed in the hope that it will 
  be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  59 Temple Place, Suite 330, Boston, MA, 02111-1307.
  
  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: zpacked.c,v 1.5 2002/10/07 08:28:56 ghostgum Exp $ */
/* Packed array operators */
#include "ghost.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"

/* - currentpacking <bool> */
private int
zcurrentpacking(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;

    push(1);
    ref_assign(op, &ref_array_packing);
    return 0;
}

/* <obj_0> ... <obj_n-1> <n> packedarray <packedarray> */
int
zpackedarray(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    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,
			     idmemory, "packedarray");
    osp++;
    if (code >= 0)
	*osp = parr;
    return code;
}

/* <bool> setpacking - */
private int
zsetpacking(i_ctx_t *i_ctx_p)
{
    os_ptr op = osp;
    ref cont;

    check_type(*op, t_boolean);
    make_struct(&cont, avm_local, ref_array_packing_container);
    ref_assign_old(&cont, &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. */
#undef idmemory			/****** NOTA BENE ******/
int
make_packed_array(ref * parr, ref_stack_t * pstack, uint size,
		  gs_dual_memory_t *idmemory, client_name_t cname)
{
    uint i;
    const ref *pref;
    uint idest = 0, ishort = 0;
    ref_packed *pbody;
    ref_packed *pdest;
    ref_packed *pshort;		/* points to start of */
				/* last run of short elements */
    gs_ref_memory_t *imem = idmemory->current;
    uint space = imemory_space(imem);
    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:
		/* Check for local-into-global store. */
		store_check_space(space, pref);
		/* falls through */
	    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. */
		store_check_space(space, pref);
	}
	/* 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 = -(int)idest & (packed_per_ref - 1);	/* padding at end */

    /* Now we can allocate the array. */

    code = gs_alloc_ref_array(imem, &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 | space, size,
		      packed, pbody + skip);
    }
    return 0;
}

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

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