/* Generic single linked list to keep various information 
   Copyright (C) 1993, 1994, 1996 Free Software Foundation, Inc.
   Contributed by Kresten Krab Thorup.

This file is part of GNU CC.

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

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* As a special exception, if you link this library with files compiled with
   GCC to produce an executable, this does not cause the resulting executable
   to be covered by the GNU General Public License. This exception does not
   however invalidate any other reasons why the executable file might be
   covered by the GNU General Public License.  */

#ifndef __GNU_OBJC_LIST_H
#define __GNU_OBJC_LIST_H

#include <objc/objc-mem.h>

struct objc_list {
  void *head;
  struct objc_list *tail;
};

/* Return a cons cell produced from (head . tail) */

static __inline__ struct objc_list* 
list_cons(void* head, struct objc_list* tail)
{
  struct objc_list* cell;

#if OBJC_WITH_GC
  cell = GC_MALLOC_UNCOLLECTABLE(sizeof(struct objc_list));
#else
  cell = malloc(sizeof(struct objc_list));
#endif
  cell->head = head;
  cell->tail = tail;
  return cell;
}

/* Return the length of a list, list_length(NULL) returns zero */

static __inline__ int
list_length(struct objc_list* list)
{
  int i = 0;
  while(list)
    {
      i += 1;
      list = list->tail;
    }
  return i;
}

/* Return the Nth element of LIST, where N count from zero.  If N 
   larger than the list length, NULL is returned  */

static __inline__ void*
list_nth(int index, struct objc_list* list)
{
  while(index-- != 0) {
    if(list->tail)
      list = list->tail;
    else
      return 0;
  }
  return list->head;
}

/* Remove the element at the head by replacing it by its successor */

static __inline__ void
list_remove_head(struct objc_list** list)
{
  if ((*list)->tail) {
    struct objc_list* tail = (*list)->tail; /* fetch next */
    *(*list) = *tail;                       /* copy next to list head */
    objc_free(tail);                        /* free next */
  }
  else {                                /* only one element in list */
    objc_free(*list);
    (*list) = 0;
  }
}


/* Remove the element with `car' set to ELEMENT */

static __inline__ void
list_remove_elem(struct objc_list** list, void* elem)
{
  while (*list) {
    if ((*list)->head == elem)
      list_remove_head(list);
    list = &((*list)->tail);
  }
}

/* Map FUNCTION over all elements in LIST */

static __inline__ void
list_mapcar(struct objc_list* list, void(*function)(void*))
{
  while (list) {
    (*function)(list->head);
    list = list->tail;
  }
}

/* Return element that has ELEM as car */

static __inline__ struct objc_list**
list_find(struct objc_list** list, void* elem)
{
  while (*list) {
    if ((*list)->head == elem)
      return list;
    list = &((*list)->tail);
  }
  return NULL;
}

/* Free list (backwards recursive) */

static void list_free(struct objc_list *list)
{
  if (list) {
    list_free(list->tail);
    objc_free(list);
  }
}
#endif /* __GNU_OBJC_LIST_H */