/* * Copyright (c) 2000-2009 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the License * may not be used to create, or enable the creation or redistribution of, * unlawful or unlicensed copies of an Apple operating system, or to * circumvent, violate, or enable the circumvention or violation of, any * terms of an Apple operating system software license agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ */ /* * Mach Operating System * Copyright (c) 1991,1990,1989,1988,1987 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. * * 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 FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* */ /* * Routines to implement queue package. */ #include <kern/queue.h> #if !defined(__GNUC__) /* * Insert element at head of queue. */ void enqueue_head( register queue_t que, register queue_entry_t elt) { elt->next = que->next; elt->prev = que; elt->next->prev = elt; que->next = elt; } /* * Insert element at tail of queue. */ void enqueue_tail( register queue_t que, register queue_entry_t elt) { elt->next = que; elt->prev = que->prev; elt->prev->next = elt; que->prev = elt; } /* * Remove and return element at head of queue. */ queue_entry_t dequeue_head( register queue_t que) { register queue_entry_t elt; if (que->next == que) return((queue_entry_t)0); elt = que->next; elt->next->prev = que; que->next = elt->next; return(elt); } /* * Remove and return element at tail of queue. */ queue_entry_t dequeue_tail( register queue_t que) { register queue_entry_t elt; if (que->prev == que) return((queue_entry_t)0); elt = que->prev; elt->prev->next = que; que->prev = elt->prev; return(elt); } /* * Remove arbitrary element from queue. * Does not check whether element is on a queue - the world * will go haywire if it isn't. */ /*ARGSUSED*/ void remqueue( register queue_entry_t elt) { elt->next->prev = elt->prev; elt->prev->next = elt->next; } /* * Routines to directly imitate the VAX hardware queue * package. */ void insque( register queue_entry_t entry, register queue_entry_t pred) { entry->next = pred->next; entry->prev = pred; (pred->next)->prev = entry; pred->next = entry; } void remque( register queue_entry_t elt) { (elt->next)->prev = elt->prev; (elt->prev)->next = elt->next; } #endif