src/utils/list.h

   1 /*
   2  * Doubly-linked list
   3  * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #ifndef LIST_H
  16 #define LIST_H
  17
  18 /**
  19  * struct dl_list - Doubly-linked list
  20  */
  21 struct dl_list {
  22         struct dl_list *next;
  23         struct dl_list *prev;
  24 };
  25
  26 static inline void dl_list_init(struct dl_list *list)
  27 {
  28         list->next = list;
  29         list->prev = list;
  30 }
  31
  32 static inline void dl_list_add(struct dl_list *list, struct dl_list *item)
  33 {
  34         item->next = list->next;
  35         item->prev = list;
  36         list->next->prev = item;
  37         list->next = item;
  38 }
  39
  40 static inline void dl_list_add_tail(struct dl_list *list, struct dl_list *item)
  41 {
  42         dl_list_add(list->prev, item);
  43 }
  44
  45 static inline void dl_list_del(struct dl_list *item)
  46 {
  47         item->next->prev = item->prev;
  48         item->prev->next = item->next;
  49         item->next = NULL;
  50         item->prev = NULL;
  51 }
  52
  53 static inline int dl_list_empty(struct dl_list *list)
  54 {
  55         return list->next == list;
  56 }
  57
  58 static inline unsigned int dl_list_len(struct dl_list *list)
  59 {
  60         struct dl_list *item;
  61         int count = 0;
  62         for (item = list->next; item != list; item = item->next)
  63                 count++;
  64         return count;
  65 }
  66
  67 #ifndef offsetof
  68 #define offsetof(type, member) ((long) &((type *) 0)->member)
  69 #endif
  70
  71 #define dl_list_entry(item, type, member) \
  72         ((type *) ((char *) item - offsetof(type, member)))
  73
  74 #define dl_list_first(list, type, member) \
  75         (dl_list_empty((list)) ? NULL : \
  76          dl_list_entry((list)->next, type, member))
  77
  78 #define dl_list_for_each(item, list, type, member) \
  79         for (item = dl_list_entry((list)->next, type, member); \
  80              &item->member != (list); \
  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 #endif /* LIST_H */