/*
 *
 * Copyright 2006 Tungsten Graphics, Inc., Bismarck, ND. USA.
 * All Rights Reserved.
 *
 * 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, sub license, 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 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 */

/**
 * \file
 * List macros heavily inspired by the Linux kernel
 * list handling. No list looping yet.
 *
 * Is not threadsafe, so common operations need to
 * be protected using an external mutex.
 */
#ifndef _U_DOUBLE_LIST_H_
#define _U_DOUBLE_LIST_H_

#include <stddef.h>

struct list_head
{
    struct list_head *prev;
    struct list_head *next;
};

static void list_inithead(struct list_head *item)
{
    item->prev = item;
    item->next = item;
}

static void list_add(struct list_head *item, struct list_head *list)
{
    item->prev = list;
    item->next = list->next;
    list->next->prev = item;
    list->next = item;
}

static void list_addtail(struct list_head *item, struct list_head *list)
{
    item->next = list;
    item->prev = list->prev;
    list->prev->next = item;
    list->prev = item;
}

static void list_replace(struct list_head *from, struct list_head *to)
{
    to->prev = from->prev;
    to->next = from->next;
    from->next->prev = to;
    from->prev->next = to;
}

static void list_del(struct list_head *item)
{
    item->prev->next = item->next;
    item->next->prev = item->prev;
}

static void list_delinit(struct list_head *item)
{
    item->prev->next = item->next;
    item->next->prev = item->prev;
    item->next = item;
    item->prev = item;
}

#define LIST_INITHEAD(__item) list_inithead(__item)
#define LIST_ADD(__item, __list) list_add(__item, __list)
#define LIST_ADDTAIL(__item, __list) list_addtail(__item, __list)
#define LIST_REPLACE(__from, __to) list_replace(__from, __to)
#define LIST_DEL(__item) list_del(__item)
#define LIST_DELINIT(__item) list_delinit(__item)

#define LIST_ENTRY(__type, __item, __field)   \
    ((__type *)(((char *)(__item)) - offsetof(__type, __field)))

#define LIST_IS_EMPTY(__list)                   \
    ((__list)->next == (__list))

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

#define LIST_FOR_EACH_ENTRY(pos, head, member)				\
   for (pos = container_of((head)->next, pos, member);			\
	&pos->member != (head);						\
	pos = container_of(pos->member.next, pos, member))

#define LIST_FOR_EACH_ENTRY_SAFE(pos, storage, head, member)	\
   for (pos = container_of((head)->next, pos, member),			\
	storage = container_of(pos->member.next, pos, member);	\
	&pos->member != (head);						\
	pos = storage, storage = container_of(storage->member.next, storage, member))

#define LIST_FOR_EACH_ENTRY_SAFE_REV(pos, storage, head, member)	\
   for (pos = container_of((head)->prev, pos, member),			\
	storage = container_of(pos->member.prev, pos, member);		\
	&pos->member != (head);						\
	pos = storage, storage = container_of(storage->member.prev, storage, member))

#define LIST_FOR_EACH_ENTRY_FROM(pos, start, head, member)		\
   for (pos = container_of((start), pos, member);			\
	&pos->member != (head);						\
	pos = container_of(pos->member.next, pos, member))

#define LIST_FOR_EACH_ENTRY_FROM_REV(pos, start, head, member)		\
   for (pos = container_of((start), pos, member);			\
	&pos->member != (head);						\
	pos = container_of(pos->member.prev, pos, member))

#endif /*_U_DOUBLE_LIST_H_*/
