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) 2010-2013 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         struct cds_hlist_node *next;
  23 };
  24
  25 struct cds_hlist_node {
  26         struct cds_hlist_node *next, *prev;
  27 };
  28
  29 /* Initialize a new list head. */
  30 static inline
  31 void CDS_INIT_HLIST_HEAD(struct cds_hlist_head *ptr)
  32 {
  33         ptr->next = NULL;
  34 }
  35
  36 #define CDS_HLIST_HEAD(name) \
  37         struct cds_hlist_head name = { NULL }
  38
  39 #define CDS_HLIST_HEAD_INIT(name) \
  40         { .next = NULL }
  41
  42 /* Get typed element from list at a given position. */
  43 #define cds_hlist_entry(ptr, type, member) \
  44         ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
  45
  46 /* Get first entry from a list. Assumes the hlist is not empty. */
  47 #define cds_hlist_first_entry(ptr, type, member) \
  48         cds_list_entry((ptr)->next, type, member)
  49
  50 static inline
  51 int cds_hlist_empty(struct cds_hlist_head *head)
  52 {
  53         return !head->next;
  54 }
  55
  56 /* Add new element at the head of the list. */
  57 static inline
  58 void cds_hlist_add_head(struct cds_hlist_node *newp,
  59                 struct cds_hlist_head *head)
  60 {
  61         if (head->next)
  62                 head->next->prev = newp;
  63         newp->next = head->next;
  64         newp->prev = (struct cds_hlist_node *) head;
  65         head->next = newp;
  66 }
  67
  68 /* Remove element from list. */
  69 static inline
  70 void cds_hlist_del(struct cds_hlist_node *elem)
  71 {
  72         if (elem->next)
  73                 elem->next->prev = elem->prev;
  74         elem->prev->next = elem->next;
  75 }
  76
  77 #define cds_hlist_for_each(pos, head) \
  78         for (pos = (head)->next; pos != NULL; pos = pos->next)
  79
  80 #define cds_hlist_for_each_safe(pos, p, head) \
  81         for (pos = (head)->next; \
  82                 (pos != NULL) && (p = pos->next, 1); \
  83                 pos = p)
  84
  85 /*
  86  * cds_hlist_for_each_entry and cds_hlist_for_each_entry_safe take
  87  * respectively 4 and 5 arguments, while the Linux kernel APIs take 3,
  88  * and 4. We implement cds_hlist_for_each_entry_2() and
  89  * cds_hlist_for_each_entry_safe_2() to follow the Linux kernel APIs.
  90  */
  91 #define cds_hlist_for_each_entry(entry, pos, head, member) \
  92         for (pos = (head)->next, \
  93                         entry = cds_hlist_entry(pos, __typeof__(*entry), member); \
  94                 pos != NULL; \
  95                 pos = pos->next, \
  96                         entry = cds_hlist_entry(pos, __typeof__(*entry), member))
  97
  98 #define cds_hlist_for_each_entry_safe(entry, pos, p, head, member) \
  99         for (pos = (head)->next, \
 100                         entry = cds_hlist_entry(pos, __typeof__(*entry), member); \
 101                 (pos != NULL) && (p = pos->next, 1); \
 102                 pos = p, \
 103                         entry = cds_hlist_entry(pos, __typeof__(*entry), member))
 104
 105 #define cds_hlist_for_each_entry_2(entry, head, member) \
 106         for (entry = ((head)->next == NULL ? NULL \
 107                         : cds_hlist_entry((head)->next, __typeof__(*entry), member)); \
 108                 entry != NULL; \
 109                 entry = (entry->member.next == NULL ? NULL \
 110                         : cds_hlist_entry(entry->member.next, __typeof__(*entry), member)))
 111
 112 #define cds_hlist_for_each_entry_safe_2(entry, e, head, member) \
 113         for (entry = ((head)->next == NULL ? NULL \
 114                         : cds_hlist_entry((head)->next, __typeof__(*entry), member)); \
 115                 (entry != NULL) && (e = (entry->member.next == NULL ? NULL \
 116                                         : cds_hlist_entry(entry->member.next, \
 117                                                 __typeof__(*entry), member)), 1); \
 118                 entry = e)
 119
 120 #endif  /* _KCOMPAT_HLIST_H */