LXR busybox/e2fsprogs/old_e2fsprogs/ext2fs/kernel-list.h

   1/* vi: set sw=4 ts=4: */
   2#ifndef LINUX_LIST_H
   3#define LINUX_LIST_H 1
   4
   5/*
   6 * Simple doubly linked list implementation.
   7 *
   8 * Some of the internal functions ("__xxx") are useful when
   9 * manipulating whole lists rather than single entries, as
  10 * sometimes we already know the next/prev entries and we can
  11 * generate better code by using them directly rather than
  12 * using the generic single-entry routines.
  13 */
  14
  15struct list_head {
  16        struct list_head *next, *prev;
  17};
  18
  19#define LIST_HEAD_INIT(name) { &(name), &(name) }
  20
  21#define LIST_HEAD(name) \
  22        struct list_head name = { &name, &name }
  23
  24#define INIT_LIST_HEAD(ptr) do { \
  25        (ptr)->next = (ptr); (ptr)->prev = (ptr); \
  26} while (0)
  27
  28#if (!defined(__GNUC__) && !defined(__WATCOMC__))
  29#define __inline__
  30#endif
  31
  32/*
  33 * Insert a new entry between two known consecutive entries.
  34 *
  35 * This is only for internal list manipulation where we know
  36 * the prev/next entries already!
  37 */
  38static __inline__ void __list_add(struct list_head * new,
  39        struct list_head * prev,
  40        struct list_head * next)
  41{
  42        next->prev = new;
  43        new->next = next;
  44        new->prev = prev;
  45        prev->next = new;
  46}
  47
  48/*
  49 * Insert a new entry after the specified head..
  50 */
  51static __inline__ void list_add(struct list_head *new, struct list_head *head)
  52{
  53        __list_add(new, head, head->next);
  54}
  55
  56/*
  57 * Insert a new entry at the tail
  58 */
  59static __inline__ void list_add_tail(struct list_head *new, struct list_head *head)
  60{
  61        __list_add(new, head->prev, head);
  62}
  63
  64/*
  65 * Delete a list entry by making the prev/next entries
  66 * point to each other.
  67 *
  68 * This is only for internal list manipulation where we know
  69 * the prev/next entries already!
  70 */
  71static __inline__ void __list_del(struct list_head * prev,
  72                                  struct list_head * next)
  73{
  74        next->prev = prev;
  75        prev->next = next;
  76}
  77
  78static __inline__ void list_del(struct list_head *entry)
  79{
  80        __list_del(entry->prev, entry->next);
  81}
  82
  83static __inline__ int list_empty(struct list_head *head)
  84{
  85        return head->next == head;
  86}
  87
  88/*
  89 * Splice in "list" into "head"
  90 */
  91static __inline__ void list_splice(struct list_head *list, struct list_head *head)
  92{
  93        struct list_head *first = list->next;
  94
  95        if (first != list) {
  96                struct list_head *last = list->prev;
  97                struct list_head *at = head->next;
  98
  99                first->prev = head;
 100                head->next = first;
 101
 102                last->next = at;
 103                at->prev = last;
 104        }
 105}
 106
 107#define list_entry(ptr, type, member) \
 108        ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
 109
 110#define list_for_each(pos, head) \
 111        for (pos = (head)->next; pos != (head); pos = pos->next)
 112
 113#endif
 114