#ifdef _cplusplus
extern"C"
{
#endif

#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 * new,
                     struct list_head * prev,
                     struct list_head * next )
    {
        next->prev = new;
        new->next = next;
        new->prev = prev;
        prev->next = new;
    }

    /**
     * list_add - add a new entry
     * @new: 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 * new, struct list_head * head )
    {
        __list_add( new, head, head->next );
    }

    /**
     * list_add_tail - add a new entry
     * @new: 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 * new, struct list_head * head )
    {
        __list_add( new, 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.
     * Note: list_empty on entry does not return true after this, the 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;
        }
    }


#ifdef _cplusplus
}
#endif