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/*

 * Copyright © 2010-2012 Intel Corporation

 * Copyright © 2010 Francisco Jerez 

 *

 * 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.

 *

 */

#ifndef _INTEL_LIST_H_

#define _INTEL_LIST_H_

#include 

/**

 * @file Classic doubly-link circular list implementation.

 * For real usage examples of the linked list, see the file test/list.c

 *

 * Example:

 * We need to keep a list of struct foo in the parent struct bar, i.e. what

 * we want is something like this.

 *

 *     struct bar {

 *          ...

 *          struct foo *list_of_foos; -----> struct foo {}, struct foo {}, struct foo{}

 *          ...

 *     }

 *

 * We need one list head in bar and a list element in all list_of_foos (both are of

 * data type 'struct list').

 *

 *     struct bar {

 *          ...

 *          struct list list_of_foos;

 *          ...

 *     }

 *

 *     struct foo {

 *          ...

 *          struct list entry;

 *          ...

 *     }

 *

 * Now we initialize the list head:

 *

 *     struct bar bar;

 *     ...

 *     list_init(&bar.list_of_foos);

 *

 * Then we create the first element and add it to this list:

 *

 *     struct foo *foo = malloc(...);

 *     ....

 *     list_add(&foo->entry, &bar.list_of_foos);

 *

 * Repeat the above for each element you want to add to the list. Deleting

 * works with the element itself.

 *      list_del(&foo->entry);

 *      free(foo);

 *

 * Note: calling list_del(&bar.list_of_foos) will set bar.list_of_foos to an empty

 * list again.

 *

 * Looping through the list requires a 'struct foo' as iterator and the

 * name of the field the subnodes use.

 *

 * struct foo *iterator;

 * list_for_each_entry(iterator, &bar.list_of_foos, entry) {

 *      if (iterator->something == ...)

 *             ...

 * }

 *

 * Note: You must not call list_del() on the iterator if you continue the

 * loop. You need to run the safe for-each loop instead:

 *

 * struct foo *iterator, *next;

 * list_for_each_entry_safe(iterator, next, &bar.list_of_foos, entry) {

 *      if (...)

 *              list_del(&iterator->entry);

 * }

 *

 */

/**

 * The linkage struct for list nodes. This struct must be part of your

 * to-be-linked struct. struct list is required for both the head of the

 * list and for each list node.

 *

 * Position and name of the struct list field is irrelevant.

 * There are no requirements that elements of a list are of the same type.

 * There are no requirements for a list head, any struct list can be a list

 * head.

 */

struct list {

    struct list *next, *prev;

};

/**

 * Initialize the list as an empty list.

 *

 * Example:

 * list_init(&bar->list_of_foos);

 *

 * @param The list to initialized.

 */

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;

}

/**

 * Insert a new element after the given list head. The new element does not

 * need to be initialised as empty list.

 * The list changes from:

 *      head → some element → ...

 * to

 *      head → new element → older element → ...

 *

 * Example:

 * struct foo *newfoo = malloc(...);

 * list_add(&newfoo->entry, &bar->list_of_foos);

 *

 * @param entry The new element to prepend to the list.

 * @param head The existing list.

 */

static inline void

list_add(struct list *entry, struct list *head)

{

    __list_add(entry, head, head->next);

}

static inline void

list_add_tail(struct list *entry, struct list *head)

{

    __list_add(entry, head->prev, head);

}

static inline void list_replace(struct list *old,

				struct list *new)

{

	new->next = old->next;

	new->next->prev = new;

	new->prev = old->prev;

	new->prev->next = new;

}

#define list_last_entry(ptr, type, member) \

    list_entry((ptr)->prev, type, member)

#define list_for_each(pos, head)				\

    for (pos = (head)->next; pos != (head); pos = pos->next)

/**

 * Append a new element to the end of the list given with this list head.

 *

 * The list changes from:

 *      head → some element → ... → lastelement

 * to

 *      head → some element → ... → lastelement → new element

 *

 * Example:

 * struct foo *newfoo = malloc(...);

 * list_append(&newfoo->entry, &bar->list_of_foos);

 *

 * @param entry The new element to prepend to the list.

 * @param head The existing list.

 */

static inline void

list_append(struct list *entry, struct list *head)

{

    __list_add(entry, head->prev, head);

}

static inline void

__list_del(struct list *prev, struct list *next)

{

	assert(next->prev == prev->next);

	next->prev = prev;

	prev->next = next;

}

static inline void

_list_del(struct list *entry)

{

    assert(entry->prev->next == entry);

    assert(entry->next->prev == entry);

    __list_del(entry->prev, entry->next);

}

/**

 * Remove the element from the list it is in. Using this function will reset

 * the pointers to/from this element so it is removed from the list. It does

 * NOT free the element itself or manipulate it otherwise.

 *

 * Using list_del on a pure list head (like in the example at the top of

 * this file) will NOT remove the first element from

 * the list but rather reset the list as empty list.

 *

 * Example:

 * list_del(&foo->entry);

 *

 * @param entry The element to remove.

 */

static inline void

list_del(struct list *entry)

{

    _list_del(entry);

    list_init(entry);

}

static inline void list_move(struct list *list, struct list *head)

{

	if (list->prev != head) {

		_list_del(list);

		list_add(list, head);

	}

}

static inline void list_move_tail(struct list *list, struct list *head)

{

	_list_del(list);

	list_add_tail(list, head);

}

/**

 * Check if the list is empty.

 *

 * Example:

 * list_is_empty(&bar->list_of_foos);

 *

 * @return True if the list contains one or more elements or False otherwise.

 */

static inline bool

list_is_empty(struct list *head)

{

    return head->next == head;

}

/**

 * Alias of container_of

 */

#define list_entry(ptr, type, member) \

    container_of(ptr, type, member)

/**

 * Retrieve the first list entry for the given list pointer.

 *

 * Example:

 * struct foo *first;

 * first = list_first_entry(&bar->list_of_foos, struct foo, list_of_foos);

 *

 * @param ptr The list head

 * @param type Data type of the list element to retrieve

 * @param member Member name of the struct list field in the list element.

 * @return A pointer to the first list element.

 */

#define list_first_entry(ptr, type, member) \

    list_entry((ptr)->next, type, member)

/**

 * Retrieve the last list entry for the given listpointer.

 *

 * Example:

 * struct foo *first;

 * first = list_last_entry(&bar->list_of_foos, struct foo, list_of_foos);

 *

 * @param ptr The list head

 * @param type Data type of the list element to retrieve

 * @param member Member name of the struct list field in the list element.

 * @return A pointer to the last list element.

 */

#define list_last_entry(ptr, type, member) \

    list_entry((ptr)->prev, type, member)

#define __container_of(ptr, sample, member)				\

    (void *)((char *)(ptr)						\

	     - ((char *)&(sample)->member - (char *)(sample)))

/**

 * Loop through the list given by head and set pos to struct in the list.

 *

 * Example:

 * struct foo *iterator;

 * list_for_each_entry(iterator, &bar->list_of_foos, entry) {

 *      [modify iterator]

 * }

 *

 * This macro is not safe for node deletion. Use list_for_each_entry_safe

 * instead.

 *

 * @param pos Iterator variable of the type of the list elements.

 * @param head List head

 * @param member Member name of the struct list in the list elements.

 *

 */

#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_reverse(pos, head, member)				\

    for (pos = __container_of((head)->prev, pos, member);		\

	 &pos->member != (head);					\

	 pos = __container_of(pos->member.prev, pos, member))

/**

 * Loop through the list, keeping a backup pointer to the element. This

 * macro allows for the deletion of a list element while looping through the

 * list.

 *

 * See list_for_each_entry for more details.

 */

#define list_for_each_entry_safe(pos, tmp, head, member)		\

    for (pos = __container_of((head)->next, pos, member),		\

	 tmp = __container_of(pos->member.next, pos, member);		\

	 &pos->member != (head);					\

	 pos = tmp, tmp = __container_of(pos->member.next, tmp, member))

#undef container_of

#define container_of(ptr, type, member) \

	((type *)((char *)(ptr) - (char *) &((type *)0)->member))

#endif /* _INTEL_LIST_H_ */