/*
 * list.h
 * 
 * This is a subset of linux's list.h intended to be used in user-space.
 * XXX The namespace conflicts with NetBSD's <sys/queue.h>
 * 
 */

#ifndef __LIST_H__
#define __LIST_H__

#define LIST_POISON1  ((void *) 0x00100100)
#define LIST_POISON2  ((void *) 0x00200200)

struct list_head {
        struct list_head *next, *prev;
};
 
/* XXX workaround for conflicts. The list API should use its own
 * namespace prefix, i.e. BLK_
 */
#ifdef LIST_HEAD_INIT
#undef LIST_HEAD_INIT
#endif
#ifndef LIST_HEAD
#undef LIST_HEAD
#endif

#define LIST_HEAD_INIT(name) { &(name), &(name) }
 
#define LIST_HEAD(name) \
        struct list_head name = LIST_HEAD_INIT(name)

static inline void INIT_LIST_HEAD(struct list_head *list)
{
	list->next = list;
	list->prev = list;
}

static inline void __list_add(struct list_head *new,
                              struct list_head *prev,
                              struct list_head *next)
{
        next->prev = new;
        new->next = next;
        new->prev = prev;
        prev->next = new;
}

static inline void list_add(struct list_head *new, struct list_head *head)
{
        __list_add(new, head, head->next);
}

static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
	__list_add(new, head->prev, head);
}

static inline void __list_del(struct list_head * prev, struct list_head * next)
{
        next->prev = prev;
        prev->next = next;
}

static inline void list_del(struct list_head *entry)
{
        __list_del(entry->prev, entry->next);
        entry->next = LIST_POISON1;
        entry->prev = LIST_POISON2;
}

static inline void list_del_init(struct list_head *entry)
{
	__list_del(entry->prev, entry->next);
	INIT_LIST_HEAD(entry);
}

static inline int list_empty(const struct list_head *head)
{
	return head->next == head;
}

static inline int list_is_last(const struct list_head *list,
			       const struct list_head *head)
{
	return list->next == head;
}

static inline void __list_splice(const struct list_head *list,
				 struct list_head *prev,
				 struct list_head *next)
{
	struct list_head *first = list->next;
	struct list_head *last = list->prev;

	first->prev = prev;
	prev->next = first;

	last->next = next;
	next->prev = last;
}

static inline void list_splice(const struct list_head *list,
			       struct list_head *head)
{
	if (!list_empty(list))
		__list_splice(list, head, head->next);
}

#define list_entry(ptr, type, member)                                   \
        ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))

#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))

#endif /* __LIST_H__ */
