/*
    structure.c -- Structure interface.
*/
/*
    Copyright (c) 1984, Taiichi Yuasa and Masami Hagiya.
    Copyright (c) 1990, Giuseppe Attardi.
    Copyright (c) 2001, Juan Jose Garcia Ripoll.

    ECL is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    See file '../Copyright' for full details.
*/


#include "ecl.h"

/******************************* ------- ******************************/

#ifdef CLOS
bool
structure_subtypep(cl_object x, cl_object y)
{ cl_object superiors;
  if (CLASS_NAME(x) == y)
    return(TRUE);
  for (superiors=CLASS_SUPERIORS(x); superiors!=Cnil;
       superiors=CDR(superiors)) {
    if (structure_subtypep(CAR(superiors), y))
      return(TRUE);
  }
  return(FALSE);
}
#else
bool
structure_subtypep(cl_object x, cl_object y)
{
	do {
		if (!SYMBOLP(x))
			return(FALSE);
		if (x == y)
			return(TRUE);
		x = get(x, @'si::structure-include', Cnil);
	} while (x != Cnil);
	return(FALSE);
}
#endif /* CLOS */

cl_object
si_structure_subtype_p(cl_object x, cl_object y)
{
	@(return ((type_of(x) == T_STRUCTURE
		     && structure_subtypep(STYPE(x), y)) ? Ct : Cnil))
}

#ifndef CLOS
/* This is only used for printing. Should not cons!! */ 
cl_object
structure_to_list(cl_object x)
{
	cl_object *p, r, s;
	int i, n;

	s = getf(SNAME(x)->symbol.plist,
	         @'si::structure-slot-descriptions', Cnil);
	p = &CDR(r = CONS(SNAME(x), Cnil));
	for (i=0, n=SLENGTH(x);  !endp(s) && i<n;  s=CDR(s), i++) {
		p = &(CDR(*p = CONS(cl_car(CAR(s)), Cnil)));
		p = &(CDR(*p = CONS(SLOT(x, i), Cnil)));
	}
	return(r);
}
#else
cl_object
structure_to_list(cl_object x)
{ FEerror("Should never be called!",0);
}
#endif /* CLOS */

@(defun si::make_structure (type &rest args)
	cl_object x;
	int i;
@
	x = cl_alloc_object(T_STRUCTURE);
	STYPE(x) = type;
	SLOTS(x) = NULL;	/* for GC sake */
	SLENGTH(x) = --narg;
	SLOTS(x) = (cl_object *)cl_alloc_align(sizeof(cl_object)*narg, sizeof(cl_object));
	for (i = 0;  i < narg;  i++)
		SLOT(x, i) = cl_va_arg(args);
	@(return x)
@)

cl_object
si_copy_structure(cl_object x)
{
	cl_index j, size;
	cl_object y;

	if (!si_structurep(x))
		FEwrong_type_argument(@'structure', x);
	y = cl_alloc_object(T_STRUCTURE);
	STYPE(y) = STYPE(x);
	SLENGTH(y) = j = SLENGTH(x);
	size = sizeof(cl_object)*j;
	SLOTS(y) = NULL;	/* for GC sake */
	SLOTS(y) = (cl_object *)cl_alloc_align(size, sizeof(cl_object));
	memcpy(SLOTS(y), SLOTS(x), size);
	@(return y)
}

/* Kept only for compatibility. One should use class-of or type-of. */
cl_object
si_structure_name(cl_object s)
{
	if (!si_structurep(s))
		FEwrong_type_argument(@'structure', s);
	@(return SNAME(s))
}

cl_object
si_structure_ref(cl_object x, cl_object type, cl_object index)
{
	if (type_of(x) != T_STRUCTURE ||
	    !structure_subtypep(STYPE(x), type))
		FEwrong_type_argument(type, x);
	@(return SLOT(x, fix(index)))
}

cl_object
structure_ref(cl_object x, cl_object name, int n)
{

	if (type_of(x) != T_STRUCTURE ||
	    !structure_subtypep(STYPE(x), name))
		FEwrong_type_argument(name, x);
	return(SLOT(x, n));
}

cl_object
si_structure_set(cl_object x, cl_object type, cl_object index, cl_object val)
{
	if (type_of(x) != T_STRUCTURE ||
	    !structure_subtypep(STYPE(x), type))
		FEwrong_type_argument(type, x);
	SLOT(x, fix(index)) = val;
	@(return val)
}

cl_object
structure_set(cl_object x, cl_object name, int n, cl_object v)
{

	if (type_of(x) != T_STRUCTURE ||
	    !structure_subtypep(STYPE(x), name))
		FEwrong_type_argument(name, x);
	SLOT(x, n) = v;
	return(v);
}

cl_object
si_structurep(cl_object s)
{
#ifdef CLOS
	if (type_of(s) == t_instance &&
	    structure_subtypep(CLASS_OF(s), @'structure-object'))
		return Ct;
#else
	if (type_of(s) == t_structure)
		return Ct;
#endif
	else
		return Cnil;
}

cl_object
si_rplaca_nthcdr(cl_object x, cl_object idx, cl_object v)
{
/*
	Used in DEFSETF forms generated by DEFSTRUCT.
	(si:rplaca-nthcdr x i v) is equivalent to 
	(progn (rplaca (nthcdr i x) v) v).
*/
	cl_fixnum i;
	cl_object l;

	assert_type_cons(x);
	for (i = fixnnint(idx), l = x;  i > 0; --i) {
		l = CDR(l);
		if (endp(l)) FEtype_error_index(idx);
	}
	CAR(l) = v;
	@(return v)
}

cl_object
si_list_nth(cl_object idx, cl_object x)
{
/*
	Used in structure access functions generated by DEFSTRUCT.
	si:list-nth is similar to nth except that
	(si:list-nth i x) is error if the length of the list x is less than i.
*/
	cl_fixnum i;
	cl_object l;

	assert_type_cons(x);
	for (i = fixnnint(idx), l = x;  i > 0; --i) {
		l = CDR(l);
		if (endp(l)) FEtype_error_index(idx);
	}
	@(return CAR(l))
}