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 */ 15 struct dl_list { 16 struct dl_list *next; 17 struct dl_list *prev; 18 }; 19 20 static inline void dl_list_init(struct dl_list *list) 21 { 22 list->next = list; 23 list->prev = list; 24 } 25 26 static 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 34 static inline void dl_list_add_tail(struct dl_list *list, struct dl_list *item) 35 { 36 dl_list_add(list->prev, item); 37 } 38 39 static 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 47 static inline int dl_list_empty(struct dl_list *list) 48 { 49 return list->next == list; 50 } 51 52 static 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