1/*
2 * Doubly-linked list
3 * Copyright (c) 2009, 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
20static inline void dl_list_init(struct dl_list *list)
21{
22	list->next = list;
23	list->prev = list;
24}
25
26static inline void dl_list_add(struct dl_list *list, struct dl_list *item)
27{
28	item->next = list->next;
29	item->prev = list;
30	list->next->prev = item;
31	list->next = item;
32}
33
34static inline void dl_list_add_tail(struct dl_list *list, struct dl_list *item)
35{
36	dl_list_add(list->prev, item);
37}
38
39static inline void dl_list_del(struct dl_list *item)
40{
41	item->next->prev = item->prev;
42	item->prev->next = item->next;
43	item->next = NULL;
44	item->prev = NULL;
45}
46
47static inline int dl_list_empty(struct dl_list *list)
48{
49	return list->next == list;
50}
51
52static inline unsigned int dl_list_len(struct dl_list *list)
53{
54	struct dl_list *item;
55	int count = 0;
56	for (item = list->next; item != list; item = item->next)
57		count++;
58	return count;
59}
60
61#ifndef offsetof
62#define offsetof(type, member) ((long) &((type *) 0)->member)
63#endif
64
65#define dl_list_entry(item, type, member) \
66	((type *) ((char *) item - offsetof(type, member)))
67
68#define dl_list_first(list, type, member) \
69	(dl_list_empty((list)) ? NULL : \
70	 dl_list_entry((list)->next, type, member))
71
72#define dl_list_last(list, type, member) \
73	(dl_list_empty((list)) ? NULL : \
74	 dl_list_entry((list)->prev, type, member))
75
76#define dl_list_for_each(item, list, type, member) \
77	for (item = dl_list_entry((list)->next, type, member); \
78	     &item->member != (list); \
79	     item = dl_list_entry(item->member.next, type, member))
80
81#define dl_list_for_each_safe(item, n, list, type, member) \
82	for (item = dl_list_entry((list)->next, type, member), \
83		     n = dl_list_entry(item->member.next, type, member); \
84	     &item->member != (list); \
85	     item = n, n = dl_list_entry(n->member.next, type, member))
86
87#define dl_list_for_each_reverse(item, list, type, member) \
88	for (item = dl_list_entry((list)->prev, type, member); \
89	     &item->member != (list); \
90	     item = dl_list_entry(item->member.prev, type, member))
91
92#define DEFINE_DL_LIST(name) \
93	struct dl_list name = { &(name), &(name) }
94
95#endif /* LIST_H */
96