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/* vi: set sw=4 ts=4: */
#include "list.h"
/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
void __list_add(struct list_head * add,
struct list_head * prev,
struct list_head * next)
{
next->prev = add;
add->next = next;
add->prev = prev;
prev->next = add;
}
/*
* list_add - add a new entry
* @add: new entry to be added
* @head: list head to add it after
*
* Insert a new entry after the specified head.
* This is good for implementing stacks.
*/
void list_add(struct list_head *add, struct list_head *head)
{
__list_add(add, head, head->next);
}
/*
* list_add_tail - add a new entry
* @add: new entry to be added
* @head: list head to add it before
*
* Insert a new entry before the specified head.
* This is useful for implementing queues.
*/
void list_add_tail(struct list_head *add, struct list_head *head)
{
__list_add(add, head->prev, head);
}
/*
* Delete a list entry by making the prev/next entries
* point to each other.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
void __list_del(struct list_head * prev, struct list_head * next)
{
next->prev = prev;
prev->next = next;
}
/*
* list_del - deletes entry from list.
* @entry: the element to delete from the list.
*
* list_empty() on @entry does not return true after this, @entry is
* in an undefined state.
*/
void list_del(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
}
/*
* list_del_init - deletes entry from list and reinitialize it.
* @entry: the element to delete from the list.
*/
void list_del_init(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
INIT_LIST_HEAD(entry);
}
/*
* list_empty - tests whether a list is empty
* @head: the list to test.
*/
int list_empty(struct list_head *head)
{
return head->next == head;
}
/*
* list_splice - join two lists
* @list: the new list to add.
* @head: the place to add it in the first list.
*/
void list_splice(struct list_head *list, struct list_head *head)
{
struct list_head *first = list->next;
if (first != list) {
struct list_head *last = list->prev;
struct list_head *at = head->next;
first->prev = head;
head->next = first;
last->next = at;
at->prev = last;
}
}
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