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