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Diffstat (limited to 'list.h')
| -rw-r--r-- | list.h | 166 |
1 files changed, 166 insertions, 0 deletions
@@ -0,0 +1,166 @@ +/* + * Copyright (C) 2002 Free Software Foundation, Inc. + * (originally part of the GNU C Library and Userspace RCU) + * Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. + * + * Copyright (C) 2009 Pierre-Marc Fournier + * Conversion to RCU list. + * Copyright (C) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see + * <http://www.gnu.org/licenses/>. + */ + +#ifndef LIST_H +#define LIST_H 1 + +/* + * The definitions of this file are adopted from those which can be + * found in the Linux kernel headers to enable people familiar with the + * latter find their way in these sources as well. + */ + +/* Basic type for the double-link list. */ +struct list_head { + struct list_head *next, *prev; +}; + +/* avoid conflicts with BSD-only sys/queue.h */ +#undef LIST_HEAD +/* Define a variable with the head and tail of the list. */ +#define LIST_HEAD(name) \ + struct list_head name = { &(name), &(name) } + +/* Initialize a new list head. */ +#define INIT_LIST_HEAD(ptr) \ + (ptr)->next = (ptr)->prev = (ptr) + +#define LIST_HEAD_INIT(name) { &(name), &(name) } + +/* Add new element at the head of the list. */ +static inline void list_add(struct list_head *newp, struct list_head *head) +{ + head->next->prev = newp; + newp->next = head->next; + newp->prev = head; + head->next = newp; +} + +/* Add new element at the tail of the list. */ +static inline void list_add_tail(struct list_head *newp, struct list_head *head) +{ + head->prev->next = newp; + newp->next = head; + newp->prev = head->prev; + head->prev = newp; +} + +/* Remove element from list. */ +static inline void __list_del(struct list_head *prev, struct list_head *next) +{ + next->prev = prev; + prev->next = next; +} + +/* Remove element from list. */ +static inline void list_del(struct list_head *elem) +{ + __list_del(elem->prev, elem->next); +} + +/* Remove element from list, initializing the element's list pointers. */ +static inline void list_del_init(struct list_head *elem) +{ + list_del(elem); + INIT_LIST_HEAD(elem); +} + +/* Delete from list, add to another list as head. */ +static inline void list_move(struct list_head *elem, struct list_head *head) +{ + __list_del(elem->prev, elem->next); + list_add(elem, head); +} + +/* Replace an old entry. */ +static inline void list_replace(struct list_head *old, struct list_head *newp) +{ + newp->next = old->next; + newp->prev = old->prev; + newp->prev->next = newp; + newp->next->prev = newp; +} + +/* Join two lists. */ +static inline void list_splice(struct list_head *add, struct list_head *head) +{ + /* Do nothing if the list which gets added is empty. */ + if (add != add->next) { + add->next->prev = head; + add->prev->next = head->next; + head->next->prev = add->prev; + head->next = add->next; + } +} + +/* Get typed element from list at a given position. */ +#define list_entry(ptr, type, member) \ + ((type *) ((char *) (ptr) - offsetof(type, member))) + +/* Get first entry from a list. */ +#define list_first_entry(ptr, type, member) \ + list_entry((ptr)->next, type, member) + +/* Iterate forward over the elements of the list. */ +#define list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/* + * Iterate forward over the elements list. The list elements can be + * removed from the list while doing this. + */ +#define list_for_each_safe(pos, p, head) \ + for (pos = (head)->next, p = pos->next; \ + pos != (head); \ + pos = p, p = pos->next) + +/* Iterate backward over the elements of the list. */ +#define list_for_each_prev(pos, head) \ + for (pos = (head)->prev; pos != (head); pos = pos->prev) + +/* + * Iterate backwards over the elements list. The list elements can be + * removed from the list while doing this. + */ +#define list_for_each_prev_safe(pos, p, head) \ + for (pos = (head)->prev, p = pos->prev; \ + pos != (head); \ + pos = p, p = pos->prev) + +static inline int list_empty(struct list_head *head) +{ + return head == head->next; +} + +static inline void list_replace_init(struct list_head *old, + struct list_head *newp) +{ + struct list_head *head = old->next; + + list_del(old); + list_add_tail(newp, head); + INIT_LIST_HEAD(old); +} + +#endif /* LIST_H */ |