include/urcu/list.h

   1 /*
   2  * Copyright (C) 2002 Free Software Foundation, Inc.
   3  * (originally part of the GNU C Library)
   4  * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
   5  *
   6  * Copyright (C) 2009 Pierre-Marc Fournier
   7  * Conversion to RCU list.
   8  * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * This library is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * This library is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with this library; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 #ifndef _CDS_LIST_H
  26 #define _CDS_LIST_H     1
  27
  28 #include <urcu/compiler.h>
  29
  30 /*
  31  * The definitions of this file are adopted from those which can be
  32  * found in the Linux kernel headers to enable people familiar with the
  33  * latter find their way in these sources as well.
  34  */
  35
  36 /* Basic type for the double-link list. */
  37 struct cds_list_head {
  38         struct cds_list_head *next, *prev;
  39 };
  40
  41 /* Define a variable with the head and tail of the list. */
  42 #define CDS_LIST_HEAD(name) \
  43         struct cds_list_head name = { &(name), &(name) }
  44
  45 /* Initialize a new list head. */
  46 #define CDS_INIT_LIST_HEAD(ptr) \
  47         (ptr)->next = (ptr)->prev = (ptr)
  48
  49 #define CDS_LIST_HEAD_INIT(name) { .next = &(name), .prev = &(name) }
  50
  51 /* Add new element at the head of the list. */
  52 static inline
  53 void cds_list_add(struct cds_list_head *newp, struct cds_list_head *head)
  54 {
  55         head->next->prev = newp;
  56         newp->next = head->next;
  57         newp->prev = head;
  58         head->next = newp;
  59 }
  60
  61 /* Add new element at the tail of the list. */
  62 static inline
  63 void cds_list_add_tail(struct cds_list_head *newp, struct cds_list_head *head)
  64 {
  65         head->prev->next = newp;
  66         newp->next = head;
  67         newp->prev = head->prev;
  68         head->prev = newp;
  69 }
  70
  71 /* Remove element from list. */
  72 static inline
  73 void __cds_list_del(struct cds_list_head *prev, struct cds_list_head *next)
  74 {
  75         next->prev = prev;
  76         prev->next = next;
  77 }
  78
  79 /* Remove element from list. */
  80 static inline
  81 void cds_list_del(struct cds_list_head *elem)
  82 {
  83         __cds_list_del(elem->prev, elem->next);
  84 }
  85
  86 /* Remove element from list, initializing the element's list pointers. */
  87 static inline
  88 void cds_list_del_init(struct cds_list_head *elem)
  89 {
  90         cds_list_del(elem);
  91         CDS_INIT_LIST_HEAD(elem);
  92 }
  93
  94 /* Delete from list, add to another list as head. */
  95 static inline
  96 void cds_list_move(struct cds_list_head *elem, struct cds_list_head *head)
  97 {
  98         __cds_list_del(elem->prev, elem->next);
  99         cds_list_add(elem, head);
 100 }
 101
 102 /* Replace an old entry. */
 103 static inline
 104 void cds_list_replace(struct cds_list_head *old, struct cds_list_head *_new)
 105 {
 106         _new->next = old->next;
 107         _new->prev = old->prev;
 108         _new->prev->next = _new;
 109         _new->next->prev = _new;
 110 }
 111
 112 /* Join two lists. */
 113 static inline
 114 void cds_list_splice(struct cds_list_head *add, struct cds_list_head *head)
 115 {
 116         /* Do nothing if the list which gets added is empty. */
 117         if (add != add->next) {
 118                 add->next->prev = head;
 119                 add->prev->next = head->next;
 120                 head->next->prev = add->prev;
 121                 head->next = add->next;
 122         }
 123 }
 124
 125 /* Get typed element from list at a given position. */
 126 #define cds_list_entry(ptr, type, member)       caa_container_of(ptr, type, member)
 127
 128
 129 /* Get first entry from a list. */
 130 #define cds_list_first_entry(ptr, type, member) \
 131         cds_list_entry((ptr)->next, type, member)
 132
 133 /* Iterate forward over the elements of the list. */
 134 #define cds_list_for_each(pos, head) \
 135         for (pos = (head)->next; (pos) != (head); pos = (pos)->next)
 136
 137 /*
 138  * Iterate forward over the elements list. The list elements can be
 139  * removed from the list while doing this.
 140  */
 141 #define cds_list_for_each_safe(pos, p, head) \
 142         for (pos = (head)->next, p = (pos)->next; \
 143                 (pos) != (head); \
 144                 pos = (p), p = (pos)->next)
 145
 146 /* Iterate backward over the elements of the list. */
 147 #define cds_list_for_each_prev(pos, head) \
 148         for (pos = (head)->prev; (pos) != (head); pos = (pos)->prev)
 149
 150 /*
 151  * Iterate backwards over the elements list. The list elements can be
 152  * removed from the list while doing this.
 153  */
 154 #define cds_list_for_each_prev_safe(pos, p, head) \
 155         for (pos = (head)->prev, p = (pos)->prev; \
 156                 (pos) != (head); \
 157                 pos = (p), p = (pos)->prev)
 158
 159 #define cds_list_for_each_entry(pos, head, member) \
 160         for (pos = cds_list_entry((head)->next, __typeof__(*(pos)), member); \
 161                 &(pos)->member != (head); \
 162                 pos = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
 163
 164 #define cds_list_for_each_entry_reverse(pos, head, member) \
 165         for (pos = cds_list_entry((head)->prev, __typeof__(*(pos)), member); \
 166                 &(pos)->member != (head); \
 167                 pos = cds_list_entry((pos)->member.prev, __typeof__(*(pos)), member))
 168
 169 #define cds_list_for_each_entry_safe(pos, p, head, member) \
 170         for (pos = cds_list_entry((head)->next, __typeof__(*(pos)), member), \
 171                         p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member); \
 172                 &(pos)->member != (head); \
 173                 pos = (p), p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
 174
 175 /*
 176  * Same as cds_list_for_each_entry_safe, but starts from "pos" which should
 177  * point to an entry within the list.
 178  */
 179 #define cds_list_for_each_entry_safe_from(pos, p, head, member) \
 180         for (p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member); \
 181                 &(pos)->member != (head); \
 182                 pos = (p), p = cds_list_entry((pos)->member.next, __typeof__(*(pos)), member))
 183
 184 static inline
 185 int cds_list_empty(struct cds_list_head *head)
 186 {
 187         return head == head->next;
 188 }
 189
 190 static inline
 191 void cds_list_replace_init(struct cds_list_head *old,
 192                 struct cds_list_head *_new)
 193 {
 194         struct cds_list_head *head = old->next;
 195
 196         cds_list_del(old);
 197         cds_list_add_tail(_new, head);
 198         CDS_INIT_LIST_HEAD(old);
 199 }
 200
 201 #endif  /* _CDS_LIST_H */