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/*
Copyright (c) 2008-2012 Red Hat, Inc. <http://www.redhat.com>
This file is part of GlusterFS.
This file is licensed to you under your choice of the GNU Lesser
General Public License, version 3 or any later version (LGPLv3 or
later), or the GNU General Public License, version 2 (GPLv2), in all
cases as published by the Free Software Foundation.
*/
#ifndef _LLIST_H
#define _LLIST_H
struct list_head {
struct list_head *next;
struct list_head *prev;
};
#define INIT_LIST_HEAD(head) do { \
(head)->next = (head)->prev = head; \
} while (0)
static inline void
list_add (struct list_head *new, struct list_head *head)
{
new->prev = head;
new->next = head->next;
new->prev->next = new;
new->next->prev = new;
}
static inline void
list_add_tail (struct list_head *new, struct list_head *head)
{
new->next = head;
new->prev = head->prev;
new->prev->next = new;
new->next->prev = new;
}
/* This function will insert the element to the list in a order.
Order will be based on the compare function provided as a input.
If element to be inserted in ascending order compare should return:
0: if both the arguments are equal
>0: if first argument is greater than second argument
<0: if first argument is less than second argument */
static inline void
list_add_order (struct list_head *new, struct list_head *head,
int (*compare)(struct list_head *, struct list_head *))
{
struct list_head *pos = head->prev;
while ( pos != head ) {
if (compare(new, pos) >= 0)
break;
/* Iterate the list in the reverse order. This will have
better efficiency if the elements are inserted in the
ascending order */
pos = pos->prev;
}
list_add (new, pos);
}
static inline void
list_del (struct list_head *old)
{
old->prev->next = old->next;
old->next->prev = old->prev;
old->next = (void *)0xbabebabe;
old->prev = (void *)0xcafecafe;
}
static inline void
list_del_init (struct list_head *old)
{
old->prev->next = old->next;
old->next->prev = old->prev;
old->next = old;
old->prev = old;
}
static inline void
list_move (struct list_head *list, struct list_head *head)
{
list_del (list);
list_add (list, head);
}
static inline void
list_move_tail (struct list_head *list, struct list_head *head)
{
list_del (list);
list_add_tail (list, head);
}
static inline int
list_empty (struct list_head *head)
{
return (head->next == head);
}
static inline void
__list_splice (struct list_head *list, struct list_head *head)
{
(list->prev)->next = (head->next);
(head->next)->prev = (list->prev);
(head)->next = (list->next);
(list->next)->prev = (head);
}
static inline void
list_splice (struct list_head *list, struct list_head *head)
{
if (list_empty (list))
return;
__list_splice (list, head);
}
/* Splice moves @list to the head of the list at @head. */
static inline void
list_splice_init (struct list_head *list, struct list_head *head)
{
if (list_empty (list))
return;
__list_splice (list, head);
INIT_LIST_HEAD (list);
}
static inline void
__list_append (struct list_head *list, struct list_head *head)
{
(head->prev)->next = (list->next);
(list->next)->prev = (head->prev);
(head->prev) = (list->prev);
(list->prev)->next = head;
}
static inline void
list_append (struct list_head *list, struct list_head *head)
{
if (list_empty (list))
return;
__list_append (list, head);
}
/* Append moves @list to the end of @head */
static inline void
list_append_init (struct list_head *list, struct list_head *head)
{
if (list_empty (list))
return;
__list_append (list, head);
INIT_LIST_HEAD (list);
}
static inline int
list_is_last (struct list_head *list, struct list_head *head)
{
return (list->next == head);
}
static inline int
list_is_singular(struct list_head *head)
{
return !list_empty(head) && (head->next == head->prev);
}
/**
* list_replace - replace old entry by new one
* @old : the element to be replaced
* @new : the new element to insert
*
* If @old was empty, it will be overwritten.
*/
static inline void list_replace(struct list_head *old,
struct list_head *new)
{
new->next = old->next;
new->next->prev = new;
new->prev = old->prev;
new->prev->next = new;
}
static inline void list_replace_init(struct list_head *old,
struct list_head *new)
{
list_replace(old, new);
INIT_LIST_HEAD(old);
}
#define list_entry(ptr, type, member) \
((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
#define list_first_entry(ptr, type, member) \
list_entry((ptr)->next, type, member)
#define list_last_entry(ptr, type, member) \
list_entry((ptr)->prev, type, member)
#define list_next_entry(pos, member) \
list_entry((pos)->member.next, typeof(*(pos)), member)
#define list_prev_entry(pos, member) \
list_entry((pos)->member.prev, typeof(*(pos)), member)
#define list_for_each(pos, head) \
for (pos = (head)->next; pos != (head); pos = pos->next)
#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_safe(pos, n, head, member) \
for (pos = list_entry((head)->next, typeof(*pos), member), \
n = list_entry(pos->member.next, typeof(*pos), member); \
&pos->member != (head); \
pos = n, n = list_entry(n->member.next, typeof(*n), 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_reverse(pos, n, head, member) \
for (pos = list_entry((head)->prev, typeof(*pos), member), \
n = list_entry(pos->member.prev, typeof(*pos), member); \
&pos->member != (head); \
pos = n, n = list_entry(n->member.prev, typeof(*n), member))
/*
* This list implementation has some advantages, but one disadvantage: you
* can't use NULL to check whether you're at the head or tail. Thus, the
* address of the head has to be an argument for these macros.
*/
#define list_next(ptr, head, type, member) \
(((ptr)->member.next == head) ? NULL \
: list_entry((ptr)->member.next, type, member))
#define list_prev(ptr, head, type, member) \
(((ptr)->member.prev == head) ? NULL \
: list_entry((ptr)->member.prev, type, member))
#endif /* _LLIST_H */
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