apps/plugins/mpegplayer/mpeg_linkedlist.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Linked list API declarations
  11  *
  12  * Copyright (c) 2007 Michael Sevakis
  13  *
  14  * All files in this archive are subject to the GNU General Public License.
  15  * See the file COPYING in the source tree root for full license agreement.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #ifndef MPEG_LINKEDLIST_H
  22 #define MPEG_LINKEDLIST_H
  23
  24 struct list_item
  25 {
  26     struct list_item *prev; /* previous item in list */
  27     struct list_item *next; /* next item in list */
  28 };
  29
  30 /* Utility macros to help get the actual structure pointer back */
  31 #define OFFSETOF(type, membername) ((off_t)&((type *)0)->membername)
  32 #define TYPE_FROM_MEMBER(type, memberptr, membername) \
  33     ((type *)((intptr_t)(memberptr) - OFFSETOF(type, membername)))
  34
  35 /* Initialize a master list head */
  36 void list_initialize(struct list_item *master_list_head);
  37
  38 /* Are there items after the head item? */
  39 bool list_is_empty(struct list_item *head_item);
  40
  41 /* Does the item belong to a list? */
  42 bool list_is_item_listed(struct list_item *item);
  43
  44 /* Is the item a member in a particular list? */
  45 bool list_is_member(struct list_item *master_list_head,
  46                     struct list_item *item);
  47
  48 /* Remove an item from a list - no head item needed */
  49 void list_remove_item(struct list_item *item);
  50
  51 /* Add a list item after the base item */
  52 void list_add_item(struct list_item *head_item,
  53                    struct list_item *item);
  54
  55 /* Clear list items after the head item */
  56 void list_clear_all(struct list_item *head_item);
  57
  58 /* Enumerate all items after the head item - passing each item in turn
  59  * to the callback as well as the data value. The current item may be
  60  * safely removed. Items added after the current position will be enumated
  61  * but not ones added before it. The callback may return false to stop
  62  * the enumeration. */
  63 typedef bool (*list_enum_callback_t)(struct list_item *item, intptr_t data);
  64
  65 void list_enum_items(struct list_item *head_item,
  66                      list_enum_callback_t callback,
  67                      intptr_t data);
  68
  69 #endif /* MPEG_LINKEDLIST_H */