/*
 * Copyright © 2009 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Chris Wilson <chris@chris-wilson.co.uk>
 *
 */

/* classic doubly-link circular list */
struct list {
	struct list *next, *prev;
};

static void
list_init(struct list *list)
{
	list->next = list->prev = list;
}

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

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

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

static inline void
list_del(struct list *entry)
{
	__list_del(entry->prev, entry->next);
	list_init(entry);
}

static inline bool
list_is_empty(struct list *head)
{
	return head->next == head;
}

#ifndef container_of
#define container_of(ptr, type, member) \
	(type *)((char *)(ptr) - (char *) &((type *)0)->member)
#endif

#define list_entry(ptr, type, member) \
	container_of(ptr, type, member)

#define list_first_entry(ptr, type, member) \
	list_entry((ptr)->next, type, member)

#define list_foreach(pos, head)			\
	for (pos = (head)->next; pos != (head);	pos = pos->next)

#define list_foreach_entry(pos, type, head, member)		\
	for (pos = list_entry((head)->next, type, member);\
	     &pos->member != (head);					\
	     pos = list_entry(pos->member.next, type, member))