list.h

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/* SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright(c) 2016 Intel Corporation. All rights reserved.
 *
 * Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
 *         Keyon Jie <yang.jie@linux.intel.com>
 */
 
#ifndef __SOF_LIST_H__
#define __SOF_LIST_H__
 
/* Really simple list manipulation */
 
struct list_item;
 
struct list_item {
    struct list_item *next;
    struct list_item *prev;
};
 
/* a static list head initialiser */
#define LIST_INIT(head) {&head, &head}
 
/* initialise list before any use - list will point to itself */
static inline void list_init(struct list_item *list)
{
    list->next = list;
    list->prev = list;
}
 
/* add new item to the start or head of the list */
static inline void list_item_prepend(struct list_item *item,
    struct list_item *list)
{
    struct list_item *next = list->next;
 
    next->prev = item;
    item->next = next;
    item->prev = list;
    list->next = item;
}
 
/* add new item to the end or tail of the list */
static inline void list_item_append(struct list_item *item,
    struct list_item *list)
{
    struct list_item *tail = list->prev;
 
    tail->next = item;
    item->next = list;
    item->prev = tail;
    list->prev = item;
}
 
/* delete item from the list leaves deleted list item
 *in undefined state list_is_empty will return true
 */
static inline void list_item_del(struct list_item *item)
{
    item->next->prev = item->prev;
    item->prev->next = item->next;
    list_init(item);
}
 
/* is list item the last item in list ? */
static inline int list_item_is_last(struct list_item *item,
                struct list_item *list)
{
    return item->next == list;
}
 
/* is list empty ? */
#define list_is_empty(item) \
    ((item)->next == item)
 
#define __list_object(item, type, offset) \
    ((type *)((char *)(item) - (offset)))
 
/* get the container object of the list item */
#define list_item(item, type, member) \
    __list_object(item, type, offsetof(type, member))
 
/* get the container object of the first item in the list */
#define list_first_item(list, type, member) \
    __list_object((list)->next, type, offsetof(type, member))
 
/* get the next container object in the list */
#define list_next_item(object, member) \
    list_item((object)->member.next, __typeof__(*(object)), member)
 
/* list iterator */
#define list_for_item(item, list) \
    for (item = (list)->next; item != (list); item = item->next)
 
/* list iterator */
#define list_for_item_prev(item, list) \
    for (item = (list)->prev; item != (list); item = item->prev)
 
/* list iterator - safe to delete items */
#define list_for_item_safe(item, tmp, list) \
    for (item = (list)->next, tmp = item->next;\
        item != (list); \
        item = tmp, tmp = item->next)

static inline void list_relink(struct list_item *new_list,
                   struct list_item *old_list)
{
    struct list_item *li;
 
    if (new_list->next == old_list) {
        list_init(new_list);
    } else {
        list_for_item(li, new_list)
            if (li->next == old_list)
                li->next = new_list; /* for stops here */
        list_for_item_prev(li, new_list)
            if (li->prev == old_list)
                li->prev = new_list; /* for stops here */
    }
}
 
#endif /* __SOF_LIST_H__ */