/* $Header$ */

#include <alloc.h>
#include <assert.h>

#include "position.h"
#include "scope.h"
#include "idf.h"
#include "symbol.h"
#include "type.h"
#include "message.h"
#include "langdep.h"
#include "expr.h"

int stack_offset;		/* for up and down commands */

extern long pointer_size;
extern t_addr *get_EM_regs();
extern char *memcpy();

/* Get the address of the object indicated by sym.
   Return 0 on failure,
	  address on success.
   *psize will contain size of object.
*/
t_addr
get_addr(sym, psize)
  register p_symbol	sym;
  long			*psize;
{
  p_type	tp = sym->sy_type;
  long		size = tp->ty_size;
  t_addr	*EM_regs;
  int		i;
  p_scope	sc, symsc;

  *psize = size;
  switch(sym->sy_class) {
  case VAR:
	/* exists if child exists; nm_value contains addres */
	return (t_addr) sym->sy_name.nm_value;
  case VARPAR:
  case LOCVAR:
	/* first find the stack frame in which it resides */
	symsc = base_scope(sym->sy_scope);

	/* now symsc contains the scope where the storage for sym is
	   allocated. Now find it on the stack of child.
	*/
	i = stack_offset;
	for (;;) {
		sc = 0;
		if (! (EM_regs = get_EM_regs(i++))) {
			return 0;
		}
		if (! EM_regs[AB_OFF]) {
			error("%s not available", sym->sy_idf->id_text);
			return 0;
		}
		sc = base_scope(get_scope_from_addr(EM_regs[PC_OFF]));
		if (! sc || sc->sc_start > EM_regs[PC_OFF]) {
			error("%s not available", sym->sy_idf->id_text);
			sc = 0;
			return 0;
		}
		if (sc == symsc) break;		/* found it */
	}

	if (sym->sy_class == LOCVAR) {
		/* Either local variable or value parameter */
		return EM_regs[sym->sy_name.nm_value < 0 ? LB_OFF : AB_OFF] +
				  (t_addr) sym->sy_name.nm_value;
	}

	/* If we get here, we have a var parameter. Get the parameters
	   of the current procedure invocation.
	*/
	{
		p_type proctype = sc->sc_definedby->sy_type;
		t_addr a;
		char *AB;

		size = proctype->ty_nbparams;
		if (has_static_link(sc)) size += pointer_size;
		AB = malloc((unsigned) size);
		if (! AB) {
			error("could not allocate enough memory");
			break;
		}
		if (! get_bytes(size, EM_regs[AB_OFF], AB)) {
			break;
		}
		if ((size = tp->ty_size) == 0) {
			size = compute_size(tp, AB);
			*psize = size;
		}
		a = (t_addr) get_int(AB+sym->sy_name.nm_value, pointer_size, T_UNSIGNED);
		free(AB);
		return a;
	}
  default:
	error("%s is not a variable", sym->sy_idf->id_text);
	break;
  }
  return 0;
}

/* Get the value of the symbol indicated by sym.
   Return 0 on failure,
	  1 on success.
   On success, 'buf' contains the value, and 'size' contains the size.
   For 'buf', storage is allocated by malloc; this storage must
   be freed by caller (I don't like this any more than you do, but caller
   does not know sizes).
*/
int
get_value(sym, buf, psize)
  register p_symbol	sym;
  char	**buf;
  long	*psize;
{
  p_type	tp = sym->sy_type;
  int		retval = 0;
  t_addr	a;
  long		size = tp->ty_size;

  *buf = 0;
  switch(sym->sy_class) {
  case CONST:
	*buf = malloc((unsigned) size);
	if (! *buf) {
		error("could not allocate enough memory");
		break;
	}
	switch(tp->ty_class) {
	case T_REAL:
		put_real(*buf, size, sym->sy_const.co_rval);
		break;
	case T_INTEGER:
	case T_SUBRANGE:
	case T_UNSIGNED:
	case T_ENUM:
		put_int(*buf, size, sym->sy_const.co_ival);
		break;
	case T_SET:
		memcpy(*buf, sym->sy_const.co_setval, (int) size);
		break;
	case T_STRING:
		memcpy(*buf, sym->sy_const.co_sval, (int) size);
		break;
	default:
		fatal("strange constant");
	}
	retval = 1;
	break;
  case VAR:
  case VARPAR:
  case LOCVAR:
	a = get_addr(sym, psize);
	if (a) {
		size = *psize;
		*buf = malloc((unsigned) size);
		if (! *buf) {
			error("could not allocate enough memory");
			break;
		}
		if (get_bytes(size, a, *buf)) {
			retval = 1;
		}
	}
	break;
  }

  if (retval == 0) {
	if (*buf) free(*buf);
	*buf = 0;
	*psize = 0;
  }
  else *psize = size;

  return retval;
}