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  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23 #ifndef MPEG_LINKEDLIST_H
  24 #define MPEG_LINKEDLIST_H
  25
  26 struct list_item
  27 {
  28     struct list_item *prev; /* previous item in list */
  29     struct list_item *next; /* next item in list */
  30 };
  31
  32 /* Utility macros to help get the actual structure pointer back */
  33 #define OFFSETOF(type, membername) ((off_t)&((type *)0)->membername)
  34 #define TYPE_FROM_MEMBER(type, memberptr, membername) \
  35     ((type *)((intptr_t)(memberptr) - OFFSETOF(type, membername)))
  36
  37 /* Initialize a master list head */
  38 void list_initialize(struct list_item *master_list_head);
  39
  40 /* Are there items after the head item? */
  41 bool list_is_empty(struct list_item *head_item);
  42
  43 /* Does the item belong to a list? */
  44 bool list_is_item_listed(struct list_item *item);
  45
  46 /* Is the item a member in a particular list? */
  47 bool list_is_member(struct list_item *master_list_head,
  48                     struct list_item *item);
  49
  50 /* Remove an item from a list - no head item needed */
  51 void list_remove_item(struct list_item *item);
  52
  53 /* Add a list item after the base item */
  54 void list_add_item(struct list_item *head_item,
  55                    struct list_item *item);
  56
  57 /* Clear list items after the head item */
  58 void list_clear_all(struct list_item *head_item);
  59
  60 /* Enumerate all items after the head item - passing each item in turn
  61  * to the callback as well as the data value. The current item may be
  62  * safely removed. Items added after the current position will be enumated
  63  * but not ones added before it. The callback may return false to stop
  64  * the enumeration. */
  65 typedef bool (*list_enum_callback_t)(struct list_item *item, intptr_t data);
  66
  67 void list_enum_items(struct list_item *head_item,
  68                      list_enum_callback_t callback,
  69                      intptr_t data);
  70
  71 #endif /* MPEG_LINKEDLIST_H */