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Diffstat (limited to 'lib/blkid/list.h')
-rw-r--r-- | lib/blkid/list.h | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/lib/blkid/list.h b/lib/blkid/list.h new file mode 100644 index 0000000..eb1c513 --- /dev/null +++ b/lib/blkid/list.h @@ -0,0 +1,184 @@ +#if !defined(_BLKID_LIST_H) && !defined(LIST_HEAD_INIT) +#define _BLKID_LIST_H + +#ifdef __cplusplus +extern "C" { +#endif + +#ifdef HAVE_INTTYPES_H +#include <inttypes.h> +#else +#ifdef HAVE_STDINT_H +#include <stdint.h> +#endif +#endif + +#ifdef __GNUC__ +#define _INLINE_ static __inline__ +#else /* For Watcom C */ +#define _INLINE_ static inline +#endif + +/* + * 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 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! + */ +_INLINE_ void __list_add(struct list_head * add, + struct list_head * prev, + struct list_head * next) +{ + next->prev = add; + add->next = next; + add->prev = prev; + prev->next = add; +} + +/** + * list_add - add a new entry + * @add: new entry to be added + * @head: list head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ +_INLINE_ void list_add(struct list_head *add, struct list_head *head) +{ + __list_add(add, head, head->next); +} + +/** + * list_add_tail - add a new entry + * @add: new entry to be added + * @head: list head to add it before + * + * Insert a new entry before the specified head. + * This is useful for implementing queues. + */ +_INLINE_ void list_add_tail(struct list_head *add, struct list_head *head) +{ + __list_add(add, 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! + */ +_INLINE_ void __list_del(struct list_head * prev, + struct list_head * next) +{ + next->prev = prev; + prev->next = next; +} + +/** + * list_del - deletes entry from list. + * @entry: the element to delete from the list. + * + * list_empty() on @entry does not return true after this, @entry is + * in an undefined state. + */ +_INLINE_ void list_del(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); +} + +/** + * list_del_init - deletes entry from list and reinitialize it. + * @entry: the element to delete from the list. + */ +_INLINE_ void list_del_init(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + INIT_LIST_HEAD(entry); +} + +/** + * list_empty - tests whether a list is empty + * @head: the list to test. + */ +_INLINE_ int list_empty(struct list_head *head) +{ + return head->next == head; +} + +/** + * list_splice - join two lists + * @list: the new list to add. + * @head: the place to add it in the first list. + */ +_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; + } +} + +/** + * list_entry - get the struct for this entry + * @ptr: the &struct list_head pointer. + * @type: the type of the struct this is embedded in. + * @member: the name of the list_struct within the struct. + */ +#define list_entry(ptr, type, member) \ + ((type *)((char *)(ptr)-(unsigned long)(intptr_t)(&((type *)0)->member))) + +/** + * list_for_each - iterate over elements in a list + * @pos: the &struct list_head to use as a loop counter. + * @head: the head for your list. + */ +#define list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/** + * list_for_each_safe - iterate over elements in a list, but don't dereference + * pos after the body is done (in case it is freed) + * @pos: the &struct list_head to use as a loop counter. + * @pnext: the &struct list_head to use as a pointer to the next item. + * @head: the head for your list (not included in iteration). + */ +#define list_for_each_safe(pos, pnext, head) \ + for (pos = (head)->next, pnext = pos->next; pos != (head); \ + pos = pnext, pnext = pos->next) + +#undef _INLINE_ + +#ifdef __cplusplus +} +#endif + +#endif /* _BLKID_LIST_H */ |