Add urcu list and list

[urcu.git] / urcu / list.h

diff --git a/urcu/list.h b/urcu/list.h
new file mode 100644 (file)
index 0000000..7ccb76a
--- /dev/null
+++ b/urcu/list.h
@@ -0,0 +1,145 @@
+/* Copyright (C) 2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#ifndef _LIST_H
+#define _LIST_H        1
+
+/* The definitions of this file are adopted from those which can be
+   found in the Linux kernel headers to enable people familiar with
+   the latter find their way in these sources as well.  */
+
+
+/* Basic type for the double-link list.  */
+typedef struct list_head
+{
+  struct list_head *next;
+  struct list_head *prev;
+} list_t;
+
+
+/* Define a variable with the head and tail of the list.  */
+#define LIST_HEAD(name) \
+  list_t name = { &(name), &(name) }
+
+/* Initialize a new list head.  */
+#define INIT_LIST_HEAD(ptr) \
+  (ptr)->next = (ptr)->prev = (ptr)
+
+#define LIST_HEAD_INIT(name) { .prev = &(name), .next = &(name) }
+
+/* Add new element at the head of the list.  */
+static inline void
+list_add (list_t *newp, list_t *head)
+{
+  head->next->prev = newp;
+  newp->next = head->next;
+  newp->prev = head;
+  head->next = newp;
+}
+
+
+/* Add new element at the tail of the list.  */
+static inline void
+list_add_tail (list_t *newp, list_t *head)
+{
+  head->prev->next = newp;
+  newp->next = head;
+  newp->prev = head->prev;
+  head->prev = newp;
+}
+
+
+/* Remove element from list.  */
+static inline void
+list_del (list_t *elem)
+{
+  elem->next->prev = elem->prev;
+  elem->prev->next = elem->next;
+}
+
+
+/* Join two lists.  */
+static inline void
+list_splice (list_t *add, list_t *head)
+{
+  /* Do nothing if the list which gets added is empty.  */
+  if (add != add->next)
+    {
+      add->next->prev = head;
+      add->prev->next = head->next;
+      head->next->prev = add->prev;
+      head->next = add->next;
+    }
+}
+
+
+/* Get typed element from list at a given position.  */
+#define list_entry(ptr, type, member) \
+  ((type *) ((char *) (ptr) - (unsigned long) (&((type *) 0)->member)))
+
+
+
+/* Iterate forward over the elements of the list.  */
+#define list_for_each(pos, head) \
+  for (pos = (head)->next; pos != (head); pos = pos->next)
+
+
+/* Iterate forward over the elements of the list.  */
+#define list_for_each_prev(pos, head) \
+  for (pos = (head)->prev; pos != (head); pos = pos->prev)
+
+
+/* Iterate backwards over the elements list.  The list elements can be
+   removed from the list while doing this.  */
+#define list_for_each_prev_safe(pos, p, head) \
+  for (pos = (head)->prev, p = pos->prev; \
+       pos != (head); \
+       pos = p, p = pos->prev)
+
+#define list_for_each_entry(pos, head, member)                         \
+       for (pos = list_entry((head)->next, typeof(*pos), member);      \
+            &pos->member != (head);                                    \
+            pos = list_entry(pos->member.next, typeof(*pos), member))
+
+#define list_for_each_entry_reverse(pos, head, member)                 \
+       for (pos = list_entry((head)->prev, typeof(*pos), member);      \
+            &pos->member != (head);                                    \
+            pos = list_entry(pos->member.prev, typeof(*pos), member))
+
+#define list_for_each_entry_safe(pos, p, head, member)                 \
+       for (pos = list_entry((head)->next, typeof(*pos), member),      \
+                    p = list_entry(pos->member.next,typeof(*pos), member); \
+            &pos->member != (head);                                    \
+            pos = p, p = list_entry(pos->member.next, typeof(*pos), member))
+
+static inline int list_empty(list_t *head)
+{
+       return head == head->next;
+}
+
+static inline void list_replace_init(list_t *old,
+                                    list_t *new)
+{
+       list_t *head = old->next;
+       list_del(old);
+       list_add_tail(new, head);
+       INIT_LIST_HEAD(old);
+}
+
+#endif /* list.h */