1/*
2 * Doubly-linked list
3 * Copyright (c) 2009-2019, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9#ifndef LIST_H
10#define LIST_H
11
12/**
13 * struct dl_list - Doubly-linked list
14 */
15struct dl_list {
16	struct dl_list *next;
17	struct dl_list *prev;
18};
19
20#define DL_LIST_HEAD_INIT(l) { &(l), &(l) }
21
22static inline void dl_list_init(struct dl_list *list)
23{
24	list->next = list;
25	list->prev = list;
26}
27
28static inline void dl_list_add(struct dl_list *list, struct dl_list *item)
29{
30	item->next = list->next;
31	item->prev = list;
32	list->next->prev = item;
33	list->next = item;
34}
35
36static inline void dl_list_add_tail(struct dl_list *list, struct dl_list *item)
37{
38	dl_list_add(list->prev, item);
39}
40
41static inline void dl_list_del(struct dl_list *item)
42{
43	item->next->prev = item->prev;
44	item->prev->next = item->next;
45	item->next = NULL;
46	item->prev = NULL;
47}
48
49static inline int dl_list_empty(struct dl_list *list)
50{
51	return list->next == list;
52}
53
54static inline unsigned int dl_list_len(struct dl_list *list)
55{
56	struct dl_list *item;
57	int count = 0;
58	for (item = list->next; item != list; item = item->next)
59		count++;
60	return count;
61}
62
63#ifndef offsetof
64#define offsetof(type, member) ((long) &((type *) 0)->member)
65#endif
66
67#define dl_list_entry(item, type, member) \
68	((type *) ((char *) item - offsetof(type, member)))
69
70#define dl_list_first(list, type, member) \
71	(dl_list_empty((list)) ? NULL : \
72	 dl_list_entry((list)->next, type, member))
73
74#define dl_list_last(list, type, member) \
75	(dl_list_empty((list)) ? NULL : \
76	 dl_list_entry((list)->prev, type, member))
77
78#define dl_list_for_each(item, list, type, member) \
79	for (item = dl_list_first((list), type, member); \
80	     item && item != dl_list_entry((list), type, member); \
81	     item = dl_list_entry(item->member.next, type, member))
82
83#define dl_list_for_each_safe(item, n, list, type, member) \
84	for (item = dl_list_entry((list)->next, type, member), \
85		     n = dl_list_entry(item->member.next, type, member); \
86	     &item->member != (list); \
87	     item = n, n = dl_list_entry(n->member.next, type, member))
88
89#define dl_list_for_each_reverse(item, list, type, member) \
90	for (item = dl_list_entry((list)->prev, type, member); \
91	     &item->member != (list); \
92	     item = dl_list_entry(item->member.prev, type, member))
93
94#define DEFINE_DL_LIST(name) \
95	struct dl_list name = { &(name), &(name) }
96
97#endif /* LIST_H */
98