LXR busybox/e2fsprogs/old_e2fsprogs/blkid/list.c

   1/* vi: set sw=4 ts=4: */
   2
   3#include "list.h"
   4
   5/*
   6 * Insert a new entry between two known consecutive entries.
   7 *
   8 * This is only for internal list manipulation where we know
   9 * the prev/next entries already!
  10 */
  11void __list_add(struct list_head * add,
  12        struct list_head * prev,
  13        struct list_head * next)
  14{
  15        next->prev = add;
  16        add->next = next;
  17        add->prev = prev;
  18        prev->next = add;
  19}
  20
  21/*
  22 * list_add - add a new entry
  23 * @add:        new entry to be added
  24 * @head:       list head to add it after
  25 *
  26 * Insert a new entry after the specified head.
  27 * This is good for implementing stacks.
  28 */
  29void list_add(struct list_head *add, struct list_head *head)
  30{
  31        __list_add(add, head, head->next);
  32}
  33
  34/*
  35 * list_add_tail - add a new entry
  36 * @add:        new entry to be added
  37 * @head:       list head to add it before
  38 *
  39 * Insert a new entry before the specified head.
  40 * This is useful for implementing queues.
  41 */
  42void list_add_tail(struct list_head *add, struct list_head *head)
  43{
  44        __list_add(add, head->prev, head);
  45}
  46
  47/*
  48 * Delete a list entry by making the prev/next entries
  49 * point to each other.
  50 *
  51 * This is only for internal list manipulation where we know
  52 * the prev/next entries already!
  53 */
  54void __list_del(struct list_head * prev, struct list_head * next)
  55{
  56        next->prev = prev;
  57        prev->next = next;
  58}
  59
  60/*
  61 * list_del - deletes entry from list.
  62 * @entry:      the element to delete from the list.
  63 *
  64 * list_empty() on @entry does not return true after this, @entry is
  65 * in an undefined state.
  66 */
  67void list_del(struct list_head *entry)
  68{
  69        __list_del(entry->prev, entry->next);
  70}
  71
  72/*
  73 * list_del_init - deletes entry from list and reinitialize it.
  74 * @entry:      the element to delete from the list.
  75 */
  76void list_del_init(struct list_head *entry)
  77{
  78        __list_del(entry->prev, entry->next);
  79        INIT_LIST_HEAD(entry);
  80}
  81
  82/*
  83 * list_empty - tests whether a list is empty
  84 * @head:       the list to test.
  85 */
  86int list_empty(struct list_head *head)
  87{
  88        return head->next == head;
  89}
  90
  91/*
  92 * list_splice - join two lists
  93 * @list:       the new list to add.
  94 * @head:       the place to add it in the first list.
  95 */
  96void list_splice(struct list_head *list, struct list_head *head)
  97{
  98        struct list_head *first = list->next;
  99
 100        if (first != list) {
 101                struct list_head *last = list->prev;
 102                struct list_head *at = head->next;
 103
 104                first->prev = head;
 105                head->next = first;
 106
 107                last->next = at;
 108                at->prev = last;
 109        }
 110}
 111