/* vim: set ts=4 sw=4 ai:
 * tq.h -- tailq implementation derived from NetBSD's queue.h
 */

#ifndef TQ_H
#define TQ_H

struct tqe {
	void *data;
	struct tqe *next;
	struct tqe **pprev;
};

struct tqh {
	struct tqe *first;
	struct tqe **last;
};

#define tq_first(hd) ((hd)->first)
#define tq_last(hd) (*(((struct tqh *)(void *)((hd)->last))->last))
#define tq_next(e) ((e)->next)
#define tq_prev(e) (*(((struct tqh *)(void *)((e)->pprev))->last))
#define tq_empty(hd) (((hd)->first) == NULL)
#define tq_init(hd) do { \
	(hd)->first = NULL; \
	(hd)->last = &(hd)->first; \
} while (0)


#define tq_foreach(var,head) \
	for ((var) = ((head)->first); \
		(var) != NULL; \
		(var) = ((var)->next))

#define tq_foreach_safe(var,head,vnext) \
	for ((var) = ((head)->first); \
		(var) != NULL && ((vnext) = tq_next((var)), 1); \
		(var) = (vnext))

#define tq_foreach_reverse(var,head) \
	for ((var) = tq_last((head)); \
		(var) != NULL; \
		(var) = tq_prev((var)))

#define tq_foreach_reverse_safe(var,head,vprev) \
	for ((var) = tq_last((head)); \
		(var) != NULL && ((vprev) = tq_prev((var)),1); \
		(var) = (vprev))

struct tqh *tq_new(void);
struct tqe *tq_elem_new(void *);
void tq_insert_head(struct tqh *, struct tqe *);
void tq_insert_tail(struct tqh *, struct tqe *);
void tq_insert_after(struct tqh *, struct tqe *, struct tqe *);
void tq_insert_before(struct tqh *, struct tqe *, struct tqe *);
void tq_remove(struct tqh *, struct tqe *);
void tq_replace(struct tqh *, struct tqe *, struct tqe *);
void tq_concat(struct tqh *, struct tqh *);
void tq_cleanup(struct tqh *, void (*)(void *));
struct tqe *tq_find_from_data(struct tqh *, const void *, int (*)(const void *, const void *));

#endif/*!TQ_H*/