busybox/e2fsprogs/ext2fs/kernel-list.h

114 lines
2.5 KiB
C

/* vi: set sw=4 ts=4: */
#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H
/*
* Simple doubly linked list implementation.
*
* Some of the internal functions ("__xxx") are useful when
* manipulating whole lists rather than single entries, as
* sometimes we already know the next/prev entries and we can
* generate better code by using them directly rather than
* using the generic single-entry routines.
*/
struct list_head {
struct list_head *next, *prev;
};
#define LIST_HEAD_INIT(name) { &(name), &(name) }
#define LIST_HEAD(name) \
struct list_head name = { &name, &name }
#define INIT_LIST_HEAD(ptr) do { \
(ptr)->next = (ptr); (ptr)->prev = (ptr); \
} while (0)
#if (!defined(__GNUC__) && !defined(__WATCOMC__))
#define __inline__
#endif
/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
static __inline__ 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;
}
/*
* Insert a new entry after the specified head..
*/
static __inline__ void list_add(struct list_head *new, struct list_head *head)
{
__list_add(new, head, head->next);
}
/*
* Insert a new entry at the tail
*/
static __inline__ 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!
*/
static __inline__ void __list_del(struct list_head * prev,
struct list_head * next)
{
next->prev = prev;
prev->next = next;
}
static __inline__ void list_del(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
}
static __inline__ int list_empty(struct list_head *head)
{
return head->next == head;
}
/*
* Splice in "list" into "head"
*/
static __inline__ 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;
}
}
#define list_entry(ptr, type, member) \
((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
#define list_for_each(pos, head) \
for (pos = (head)->next; pos != (head); pos = pos->next)
#endif