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Diffstat (limited to 'list.h')
| -rw-r--r-- | list.h | 242 |
1 files changed, 242 insertions, 0 deletions
@@ -0,0 +1,242 @@ +/** + * \file 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. + * + * \author Copied from the linux kernel, file include/linux/list.h. + */ + +#ifndef _LIST_H +#define _LIST_H + +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; +} + +/** + * Add a new entry. + * + * \param new new entry to be added + * \param head list head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ +static inline void list_add(struct list_head *new, struct list_head *head) +{ + __list_add(new, head, head->next); +} + +/** + * Add a new entry. + * + * \param new new entry to be added + * \param head list head to add it before + * + * Insert a new entry before the specified head. + * This is useful for implementing queues. + */ +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; +} + +/** + * Deletes entry from list. + * + * \param 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. + */ +static inline void list_del(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + entry->next = (void *) 0; + entry->prev = (void *) 0; +} + +/** + * Deletes entry from list and reinitialize it. + * + * \param entry the element to delete from the list. + */ +static inline void list_del_init(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + INIT_LIST_HEAD(entry); +} + +/** + * Delete from one list and add as another's head. + * + * \param list the entry to move + * \param head the head that will precede our entry + */ +static inline void list_move(struct list_head *list, struct list_head *head) +{ + __list_del(list->prev, list->next); + list_add(list, head); +} + +/** + * Delete from one list and add as another's tail. + * + * \param list the entry to move + * \param head the head that will follow our entry + */ +static inline void list_move_tail(struct list_head *list, + struct list_head *head) +{ + __list_del(list->prev, list->next); + list_add_tail(list, head); +} + +/** + * Tests whether a list is empty. + * + * \param head the list to test. + */ +static inline int list_empty(struct list_head *head) +{ + return head->next == head; +} + +static inline void __list_splice(struct list_head *list, + struct list_head *head) +{ + struct list_head *first = list->next; + struct list_head *last = list->prev; + struct list_head *at = head->next; + + first->prev = head; + head->next = first; + + last->next = at; + at->prev = last; +} + +/** + * Join two lists. + * + * \param list the new list to add. + * \param head the place to add it in the first list. + */ +static inline void list_splice(struct list_head *list, struct list_head *head) +{ + if (!list_empty(list)) + __list_splice(list, head); +} + +/** + * Join two lists and reinitialise the emptied list. + * + * \param list the new list to add. + * \param head the place to add it in the first list. + * + * The list at \p list is reinitialised + */ +static inline void list_splice_init(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) { + __list_splice(list, head); + INIT_LIST_HEAD(list); + } +} + +/** + * Get the struct for this entry. + * + * \param ptr the &struct list_head pointer. + * \param type the type of the struct this is embedded in. + * \param member the name of the list_struct within the struct. + */ +#define list_entry(ptr, type, member) \ + ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member))) + +/** + * Iterate over a list. + * + * \param pos the struct list_head to use as a loop counter. + * \param head the head for your list. + */ +#define list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); \ + pos = pos->next) +/** + * Iterate over a list backwards. + * + * \param pos the &struct list_head to use as a loop counter. + * \param head the head for your list. + */ +#define list_for_each_prev(pos, head) \ + for (pos = (head)->prev; pos != (head); \ + pos = pos->prev) + +/** + * Iterate over a list safe against removal of list entry. + * + * \param pos the &struct list_head to use as a loop counter. + * \param n another &struct list_head to use as temporary storage + * \param head the head for your list. + */ +#define list_for_each_safe(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, n = pos->next) + +/** + * Iterate over list of given type. + * + * \param pos the type * to use as a loop counter. + * \param head the head for your list. + * \param member the name of the list_struct within the struct. + */ +#define list_for_each_entry(pos, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member)) + +#endif |