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 */ 15 struct dl_list { 16 struct dl_list *next; 17 struct dl_list *prev; 18 }; 19 20 #define DL_LIST_HEAD_INIT(l) { &(l), &(l) } 21 22 static inline void dl_list_init(struct dl_list *list) 23 { 24 list->next = list; 25 list->prev = list; 26 } 27 28 static 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 36 static inline void dl_list_add_tail(struct dl_list *list, struct dl_list *item) 37 { 38 dl_list_add(list->prev, item); 39 } 40 41 static 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 49 static inline int dl_list_empty(struct dl_list *list) 50 { 51 return list->next == list; 52 } 53 54 static 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