LIST

queue.h

/*
 * List definitions.
 */
#define LIST_HEAD(name, type)						\
struct name {								\
	struct type *lh_first;	/* first element */			\
}

#define LIST_HEAD_INITIALIZER(head)					\
	{ NULL }

#define LIST_ENTRY(type)						\
struct {								\
	struct type *le_next;	/* next element */			\
	struct type **le_prev;	/* address of previous next element */	\
}

/*
 * List functions.
 */

#define	LIST_EMPTY(head) ((head)->lh_first == NULL)

#define LIST_FIRST(head)	((head)->lh_first)

#define LIST_FOREACH(var, head, field)					\
	for((var) = (head)->lh_first; (var); (var) = (var)->field.le_next)

#define	LIST_INIT(head) do {						\
	(head)->lh_first = NULL;					\
} while (0)

#define LIST_INSERT_AFTER(listelm, elm, field) do {			\
	if (((elm)->field.le_next = (listelm)->field.le_next) != NULL)	\
		(listelm)->field.le_next->field.le_prev =		\
		    &(elm)->field.le_next;				\
	(listelm)->field.le_next = (elm);				\
	(elm)->field.le_prev = &(listelm)->field.le_next;		\
} while (0)

#define LIST_INSERT_BEFORE(listelm, elm, field) do {			\
	(elm)->field.le_prev = (listelm)->field.le_prev;		\
	(elm)->field.le_next = (listelm);				\
	*(listelm)->field.le_prev = (elm);				\
	(listelm)->field.le_prev = &(elm)->field.le_next;		\
} while (0)

#define LIST_INSERT_HEAD(head, elm, field) do {				\
	if (((elm)->field.le_next = (head)->lh_first) != NULL)		\
		(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
	(head)->lh_first = (elm);					\
	(elm)->field.le_prev = &(head)->lh_first;			\
} while (0)

#define LIST_NEXT(elm, field)	((elm)->field.le_next)

#define LIST_REMOVE(elm, field) do {					\
	if ((elm)->field.le_next != NULL)				\
		(elm)->field.le_next->field.le_prev = 			\
		    (elm)->field.le_prev;				\
	*(elm)->field.le_prev = (elm)->field.le_next;			\
} while (0)