urcu/list.h

   1 /* Copyright (C) 2002 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #ifndef _CDS_LIST_H
  21 #define _CDS_LIST_H     1
  22
  23 /* The definitions of this file are adopted from those which can be
  24    found in the Linux kernel headers to enable people familiar with
  25    the latter find their way in these sources as well.  */
  26
  27
  28 /* Basic type for the double-link list.  */
  29 struct cds_list_head
  30 {
  31   struct cds_list_head *next;
  32   struct cds_list_head *prev;
  33 };
  34
  35
  36 /* Define a variable with the head and tail of the list.  */
  37 #define CDS_LIST_HEAD(name) \
  38   struct cds_list_head name = { &(name), &(name) }
  39
  40 /* Initialize a new list head.  */
  41 #define CDS_INIT_LIST_HEAD(ptr) \
  42   (ptr)->next = (ptr)->prev = (ptr)
  43
  44 #define CDS_LIST_HEAD_INIT(name) { .prev = &(name), .next = &(name) }
  45
  46 /* Add new element at the head of the list.  */
  47 static inline void
  48 cds_list_add (struct cds_list_head *newp, struct cds_list_head *head)
  49 {
  50   head->next->prev = newp;
  51   newp->next = head->next;
  52   newp->prev = head;
  53   head->next = newp;
  54 }
  55
  56
  57 /* Add new element at the tail of the list.  */
  58 static inline void
  59 cds_list_add_tail (struct cds_list_head *newp, struct cds_list_head *head)
  60 {
  61   head->prev->next = newp;
  62   newp->next = head;
  63   newp->prev = head->prev;
  64   head->prev = newp;
  65 }
  66
  67
  68 /* Remove element from list.  */
  69 static inline void
  70 __cds_list_del (struct cds_list_head *prev, struct cds_list_head *next)
  71 {
  72   next->prev = prev;
  73   prev->next = next;
  74 }
  75
  76 /* Remove element from list.  */
  77 static inline void
  78 cds_list_del (struct cds_list_head *elem)
  79 {
  80   __cds_list_del (elem->prev, elem->next);
  81 }
  82
  83 /* Remove element from list, initializing the element's list pointers. */
  84 static inline void
  85 cds_list_del_init (struct cds_list_head *elem)
  86 {
  87         cds_list_del(elem);
  88         CDS_INIT_LIST_HEAD(elem);
  89 }
  90
  91 /* delete from list, add to another list as head */
  92 static inline void
  93 cds_list_move (struct cds_list_head *elem, struct cds_list_head *head)
  94 {
  95   __cds_list_del (elem->prev, elem->next);
  96   cds_list_add (elem, head);
  97 }
  98
  99 /* replace an old entry.
 100  */
 101 static inline void
 102 cds_list_replace(struct cds_list_head *old, struct cds_list_head *_new)
 103 {
 104         _new->next = old->next;
 105         _new->prev = old->prev;
 106         _new->prev->next = _new;
 107         _new->next->prev = _new;
 108 }
 109
 110 /* Join two lists.  */
 111 static inline void
 112 cds_list_splice (struct cds_list_head *add, struct cds_list_head *head)
 113 {
 114   /* Do nothing if the list which gets added is empty.  */
 115   if (add != add->next)
 116     {
 117       add->next->prev = head;
 118       add->prev->next = head->next;
 119       head->next->prev = add->prev;
 120       head->next = add->next;
 121     }
 122 }
 123
 124
 125 /* Get typed element from list at a given position.  */
 126 #define cds_list_entry(ptr, type, member) \
 127   ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
 128
 129
 130
 131 /* Iterate forward over the elements of the list.  */
 132 #define cds_list_for_each(pos, head) \
 133   for (pos = (head)->next; pos != (head); pos = pos->next)
 134
 135
 136 /* Iterate forward over the elements of the list.  */
 137 #define cds_list_for_each_prev(pos, head) \
 138   for (pos = (head)->prev; pos != (head); pos = pos->prev)
 139
 140
 141 /* Iterate backwards over the elements list.  The list elements can be
 142    removed from the list while doing this.  */
 143 #define cds_list_for_each_prev_safe(pos, p, head) \
 144   for (pos = (head)->prev, p = pos->prev; \
 145        pos != (head); \
 146        pos = p, p = pos->prev)
 147
 148 #define cds_list_for_each_entry(pos, head, member)                              \
 149         for (pos = cds_list_entry((head)->next, typeof(*pos), member);  \
 150              &pos->member != (head);                                    \
 151              pos = cds_list_entry(pos->member.next, typeof(*pos), member))
 152
 153 #define cds_list_for_each_entry_reverse(pos, head, member)                      \
 154         for (pos = cds_list_entry((head)->prev, typeof(*pos), member);  \
 155              &pos->member != (head);                                    \
 156              pos = cds_list_entry(pos->member.prev, typeof(*pos), member))
 157
 158 #define cds_list_for_each_entry_safe(pos, p, head, member)                      \
 159         for (pos = cds_list_entry((head)->next, typeof(*pos), member),  \
 160                      p = cds_list_entry(pos->member.next,typeof(*pos), member); \
 161              &pos->member != (head);                                    \
 162              pos = p, p = cds_list_entry(pos->member.next, typeof(*pos), member))
 163
 164 static inline int cds_list_empty(struct cds_list_head *head)
 165 {
 166         return head == head->next;
 167 }
 168
 169 static inline void cds_list_replace_init(struct cds_list_head *old,
 170                                      struct cds_list_head *_new)
 171 {
 172         struct cds_list_head *head = old->next;
 173         cds_list_del(old);
 174         cds_list_add_tail(_new, head);
 175         CDS_INIT_LIST_HEAD(old);
 176 }
 177
 178 #endif  /* _CDS_LIST_H */