diff options
Diffstat (limited to 'list.h')
-rw-r--r-- | list.h | 110 |
1 files changed, 110 insertions, 0 deletions
@@ -0,0 +1,110 @@ +// SPDX-License-Identifier: GPL-2.0-only +#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. + * + * Copyright (c) 2004 Thomas Sailer <sailer@ife.ee.ethz.ch> + * + * Based on list.h from the Linux kernel source tree. + */ + +struct list_head { + struct list_head *next, *prev; +}; + +#define LIST_HEAD_INIT(name) { &(name), &(name) } + +#define LIST_HEAD(name) \ + struct list_head name = LIST_HEAD_INIT(name) + +#define INIT_LIST_HEAD(ptr) do { \ + (ptr)->next = (ptr); (ptr)->prev = (ptr); \ +} while (0) + +/* + * 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 before the specified head.. + */ +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))) + +#endif |