urcu/hlist.h

   1 #ifndef _KCOMPAT_HLIST_H
   2 #define _KCOMPAT_HLIST_H
   3
   4 /*
   5  * Kernel sourcecode compatible lightweight single pointer list head useful
   6  * for implementing hash tables
   7  *
   8  * Copyright (C) 2009 Novell Inc.
   9  *
  10  * Author: Jan Blunck <jblunck@suse.de>
  11  *
  12  * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  13  *
  14  * This program is free software; you can redistribute it and/or modify it
  15  * under the terms of the GNU Lesser General Public License version 2.1 as
  16  * published by the Free  Software Foundation.
  17  */
  18
  19 #include <stddef.h>
  20
  21 struct cds_hlist_head
  22 {
  23         struct cds_hlist_node *next;
  24 };
  25
  26 struct cds_hlist_node
  27 {
  28         struct cds_hlist_node *next;
  29         struct cds_hlist_node *prev;
  30 };
  31
  32 /* Initialize a new list head.  */
  33 static inline void  CDS_INIT_HLIST_HEAD(struct cds_hlist_head *ptr)
  34 {
  35         ptr->next = NULL;
  36 }
  37
  38 /* Get typed element from list at a given position.  */
  39 #define cds_hlist_entry(ptr, type, member)                                      \
  40         ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
  41
  42 /* Get first entry from a list. Assumes the hlist is not empty. */
  43 #define cds_hlist_first_entry(ptr, type, member) \
  44         cds_list_entry((ptr)->next, type, member)
  45
  46 static inline int cds_hlist_empty(struct cds_hlist_head *head)
  47 {
  48         return !head->next;
  49 }
  50
  51 /* Add new element at the head of the list.  */
  52 static inline void cds_hlist_add_head (struct cds_hlist_node *newp,
  53                                    struct cds_hlist_head *head)
  54 {
  55         if (head->next)
  56                 head->next->prev = newp;
  57
  58         newp->next = head->next;
  59         newp->prev = (struct cds_hlist_node *)head;
  60         head->next = newp;
  61 }
  62
  63 /* Remove element from list.  */
  64 static inline void cds_hlist_del (struct cds_hlist_node *elem)
  65 {
  66         if (elem->next)
  67                 elem->next->prev = elem->prev;
  68
  69         elem->prev->next = elem->next;
  70 }
  71
  72 #define cds_hlist_for_each_entry(entry, pos, head, member)                      \
  73         for (pos = (head)->next,                                        \
  74                      entry = cds_hlist_entry(pos, __typeof__(*entry), member);  \
  75              pos != NULL;                                               \
  76              pos = pos->next,                                   \
  77                      entry = cds_hlist_entry(pos, __typeof__(*entry), member))
  78
  79 #define cds_hlist_for_each_entry_safe(entry, pos, p, head, member)              \
  80         for (pos = (head)->next,                                        \
  81                      entry = cds_hlist_entry(pos, __typeof__(*entry), member);  \
  82              (pos != NULL) && ({ p = pos->next; 1;});                   \
  83              pos = p,                                                   \
  84                      entry = cds_hlist_entry(pos, __typeof__(*entry), member))
  85
  86 #endif  /* _KCOMPAT_HLIST_H */