rockbox/apps/plugins/mpegplayer/mpeg_linkedlist.h

69 lines
2.6 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Linked list API declarations
*
* Copyright (c) 2007 Michael Sevakis
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef MPEG_LINKEDLIST_H
#define MPEG_LINKEDLIST_H
struct list_item
{
struct list_item *prev; /* previous item in list */
struct list_item *next; /* next item in list */
};
/* Utility macros to help get the actual structure pointer back */
#define OFFSETOF(type, membername) ((off_t)&((type *)0)->membername)
#define TYPE_FROM_MEMBER(type, memberptr, membername) \
((type *)((intptr_t)(memberptr) - OFFSETOF(type, membername)))
/* Initialize a master list head */
void list_initialize(struct list_item *master_list_head);
/* Are there items after the head item? */
bool list_is_empty(struct list_item *head_item);
/* Does the item belong to a list? */
bool list_is_item_listed(struct list_item *item);
/* Is the item a member in a particular list? */
bool list_is_member(struct list_item *master_list_head,
struct list_item *item);
/* Remove an item from a list - no head item needed */
void list_remove_item(struct list_item *item);
/* Add a list item after the base item */
void list_add_item(struct list_item *head_item,
struct list_item *item);
/* Clear list items after the head item */
void list_clear_all(struct list_item *head_item);
/* Enumerate all items after the head item - passing each item in turn
* to the callback as well as the data value. The current item may be
* safely removed. Items added after the current position will be enumated
* but not ones added before it. The callback may return false to stop
* the enumeration. */
typedef bool (*list_enum_callback_t)(struct list_item *item, intptr_t data);
void list_enum_items(struct list_item *head_item,
list_enum_callback_t callback,
intptr_t data);
#endif /* MPEG_LINKEDLIST_H */