/*-
 *
 *             Coda: an Experimental Distributed File System
 *                              Release 3.1
 *
 *           Copyright (c) 1987-1998 Carnegie Mellon University
 *                          All Rights Reserved
 *
 * Permission  to  use, copy, modify and distribute this software and its
 * documentation is hereby granted,  provided  that  both  the  copyright
 * notice  and  this  permission  notice  appear  in  all  copies  of the
 * software, derivative works or  modified  versions,  and  any  portions
 * thereof, and that both notices appear in supporting documentation, and
 * that credit is given to Carnegie Mellon University  in  all  documents
 * and publicity pertaining to direct or indirect use of this code or its
 * derivatives.
 *
 * CODA IS AN EXPERIMENTAL SOFTWARE SYSTEM AND IS  KNOWN  TO  HAVE  BUGS,
 * SOME  OF  WHICH MAY HAVE SERIOUS CONSEQUENCES.  CARNEGIE MELLON ALLOWS
 * FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION.   CARNEGIE  MELLON
 * DISCLAIMS  ANY  LIABILITY  OF  ANY  KIND  FOR  ANY  DAMAGES WHATSOEVER
 * RESULTING DIRECTLY OR INDIRECTLY FROM THE USE OF THIS SOFTWARE  OR  OF
 * ANY DERIVATIVE WORK.
 *
 * Carnegie  Mellon  encourages  users  of  this  software  to return any
 * improvements or extensions that  they  make,  and  to  grant  Carnegie
 * Mellon the rights to redistribute these changes without encumbrance.
 *
 * 	@(#) src/sys/coda/coda_kernel.h,v 1.1.1.1 1998/08/29 21:14:52 rvb Exp $
 * $FreeBSD$
 *
 */

/*
 * Macros to manipulate the queue.
 *
 * XXX: It would be good to replace this with use of queue(9) throughout the
 * Coda kernel module.
 */
#ifndef INIT_QUEUE

struct queue {
	struct queue *forw, *back;
};

#define	INIT_QUEUE(head) do {						\
	(head).forw = (struct queue *)&(head);				\
	(head).back = (struct queue *)&(head);				\
} while (0)

#define	GETNEXT(head)	(head).forw
#define	EMPTY(head)	((head).forw == &(head))
#define	EOQ(el, head)	((struct queue *)(el) == (struct queue *)&(head))

#define	INSQUE(el, head) do {						\
	(el).forw = ((head).back)->forw;				\
	(el).back = (head).back;					\
	((head).back)->forw = (struct queue *)&(el);			\
	(head).back = (struct queue *)&(el);				\
} while (0)

#define	REMQUE(el) do {							\
	((el).forw)->back = (el).back;					\
	(el).back->forw = (el).forw;					\
}  while (0)

#endif