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/*
* Circular doubly linked list implementation.
*
* Copyright (c) 2007 Marko Kreen, Skype Technologies OÜ
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/**
* @file
* Circular doubly linked list.
*/
#ifndef _USUAL_LIST_H_
#define _USUAL_LIST_H_
#include <usual/base.h>
/**
* Structure for both list nodes and heads.
*
* It is meant to be embedded in parent structure,
* which can be acquired with container_of().
*/
struct List {
/** Pointer to next node or head. */
struct List *next;
/** Pointer to previous node or head. */
struct List *prev;
};
/** Define and initialize emtpy list head */
#define LIST(var) struct List var = { &var, &var }
/** Initialize empty list head. */
static inline void list_init(struct List *list)
{
list->next = list->prev = list;
}
/** Is list empty? */
static inline int list_empty(const struct List *list)
{
return list->next == list;
}
/** Add item to the start of the list */
static inline struct List *list_prepend(struct List *list, struct List *item)
{
item->next = list->next;
item->prev = list;
list->next->prev = item;
list->next = item;
return item;
}
/** Add item to the end of the list */
static inline struct List *list_append(struct List *list, struct List *item)
{
item->next = list;
item->prev = list->prev;
list->prev->next = item;
list->prev = item;
return item;
}
/** Remove item from list */
static inline struct List *list_del(struct List *item)
{
item->prev->next = item->next;
item->next->prev = item->prev;
item->next = item->prev = item;
return item;
}
/** Remove first from list and return */
static inline struct List *list_pop(struct List *list)
{
if (list_empty(list))
return NULL;
return list_del(list->next);
}
/** Get first elem from list */
static inline struct List *list_first(const struct List *list)
{
if (list_empty(list))
return NULL;
return list->next;
}
/** Get last elem from list */
static inline struct List *list_last(const struct List *list)
{
if (list_empty(list))
return NULL;
return list->prev;
}
/** Remove first elem from list and return with casting */
#define list_pop_type(list, typ, field) \
(list_empty(list) ? NULL \
: container_of(list_del((list)->next), typ, field))
/** Loop over list */
#define list_for_each(item, list) \
for ((item) = (list)->next; \
(item) != (list); \
(item) = (item)->next)
/** Loop over list backwards */
#define list_for_each_reverse(item, list) \
for ((item) = (list)->prev; \
(item) != (list); \
(item) = (item)->prev)
/** Loop over list and allow removing item */
#define list_for_each_safe(item, list, tmp) \
for ((item) = (list)->next, (tmp) = (list)->next->next; \
(item) != (list); \
(item) = (tmp), (tmp) = (tmp)->next)
/** Loop over list backwards and allow removing item */
#define list_for_each_reverse_safe(item, list, tmp) \
for ((item) = (list)->prev, (tmp) = (list)->prev->prev; \
(item) != (list); \
(item) = (tmp), (tmp) = (tmp)->prev)
/** Comparator function signature for list_sort() */
typedef int (*list_cmp_f)(const struct List *a, const struct List *b);
/**
* Sort list.
*
* This implementation uses stable merge sort which operates in-place.
*/
void list_sort(struct List *list, list_cmp_f cmp_func);
#endif
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