mirror of
https://github.com/sheumann/hush.git
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181 lines
4.3 KiB
C
181 lines
4.3 KiB
C
/* vi: set sw=4 ts=4: */
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#if !defined(_BLKID_LIST_H) && !defined(LIST_HEAD)
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#define _BLKID_LIST_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifdef __GNUC__
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#define _INLINE_ static __inline__
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#else /* For Watcom C */
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#define _INLINE_ static inline
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#endif
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/*
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* Simple doubly linked list implementation.
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*
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* Some of the internal functions ("__xxx") are useful when
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* manipulating whole lists rather than single entries, as
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* sometimes we already know the next/prev entries and we can
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* generate better code by using them directly rather than
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* using the generic single-entry routines.
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*/
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struct list_head {
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struct list_head *next, *prev;
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};
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#define LIST_HEAD_INIT(name) { &(name), &(name) }
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#define LIST_HEAD(name) \
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struct list_head name = LIST_HEAD_INIT(name)
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#define INIT_LIST_HEAD(ptr) do { \
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(ptr)->next = (ptr); (ptr)->prev = (ptr); \
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} while (0)
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/*
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* Insert a new entry between two known consecutive entries.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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_INLINE_ void __list_add(struct list_head * add,
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struct list_head * prev,
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struct list_head * next)
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{
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next->prev = add;
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add->next = next;
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add->prev = prev;
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prev->next = add;
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}
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/**
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* list_add - add a new entry
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* @add: new entry to be added
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* @head: list head to add it after
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*
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* Insert a new entry after the specified head.
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* This is good for implementing stacks.
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*/
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_INLINE_ void list_add(struct list_head *add, struct list_head *head)
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{
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__list_add(add, head, head->next);
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}
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/**
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* list_add_tail - add a new entry
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* @add: new entry to be added
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* @head: list head to add it before
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*
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* Insert a new entry before the specified head.
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* This is useful for implementing queues.
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*/
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_INLINE_ void list_add_tail(struct list_head *add, struct list_head *head)
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{
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__list_add(add, head->prev, head);
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}
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/*
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* Delete a list entry by making the prev/next entries
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* point to each other.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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_INLINE_ void __list_del(struct list_head * prev,
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struct list_head * next)
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{
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next->prev = prev;
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prev->next = next;
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}
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/**
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* list_del - deletes entry from list.
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* @entry: the element to delete from the list.
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*
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* list_empty() on @entry does not return true after this, @entry is
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* in an undefined state.
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*/
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_INLINE_ void list_del(struct list_head *entry)
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{
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__list_del(entry->prev, entry->next);
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}
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/**
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* list_del_init - deletes entry from list and reinitialize it.
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* @entry: the element to delete from the list.
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*/
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_INLINE_ void list_del_init(struct list_head *entry)
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{
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__list_del(entry->prev, entry->next);
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INIT_LIST_HEAD(entry);
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}
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/**
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* list_empty - tests whether a list is empty
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* @head: the list to test.
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*/
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_INLINE_ int list_empty(struct list_head *head)
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{
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return head->next == head;
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}
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/**
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* list_splice - join two lists
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* @list: the new list to add.
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* @head: the place to add it in the first list.
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*/
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_INLINE_ void list_splice(struct list_head *list, struct list_head *head)
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{
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struct list_head *first = list->next;
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if (first != list) {
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struct list_head *last = list->prev;
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struct list_head *at = head->next;
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first->prev = head;
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head->next = first;
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last->next = at;
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at->prev = last;
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}
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}
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/**
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* list_entry - get the struct for this entry
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* @ptr: the &struct list_head pointer.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_entry(ptr, type, member) \
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((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
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/**
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* list_for_each - iterate over elements in a list
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* @pos: the &struct list_head to use as a loop counter.
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* @head: the head for your list.
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*/
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#define list_for_each(pos, head) \
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for (pos = (head)->next; pos != (head); pos = pos->next)
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/**
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* list_for_each_safe - iterate over elements in a list, but don't dereference
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* pos after the body is done (in case it is freed)
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* @pos: the &struct list_head to use as a loop counter.
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* @pnext: the &struct list_head to use as a pointer to the next item.
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* @head: the head for your list (not included in iteration).
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*/
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#define list_for_each_safe(pos, pnext, head) \
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for (pos = (head)->next, pnext = pos->next; pos != (head); \
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pos = pnext, pnext = pos->next)
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#undef _INLINE_
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#ifdef __cplusplus
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}
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#endif
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#endif /* _BLKID_LIST_H */
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