lstIsAtEnd.c revision 236769 
1/*	$NetBSD: lstIsAtEnd.c,v 1.13 2008/02/15 21:29:50 christos Exp $	*/
2
3/*
4 * Copyright (c) 1988, 1989, 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Adam de Boor.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#ifndef MAKE_NATIVE
36static char rcsid[] = "$NetBSD: lstIsAtEnd.c,v 1.13 2008/02/15 21:29:50 christos Exp $";
37#else
38#include <sys/cdefs.h>
39#ifndef lint
40#if 0
41static char sccsid[] = "@(#)lstIsAtEnd.c	8.1 (Berkeley) 6/6/93";
42#else
43__RCSID("$NetBSD: lstIsAtEnd.c,v 1.13 2008/02/15 21:29:50 christos Exp $");
44#endif
45#endif /* not lint */
46#endif
47
48/*-
49 * LstIsAtEnd.c --
50 *	Tell if the current node is at the end of the list.
51 *	The sequential functions access the list in a slightly different way.
52 *	CurPtr points to their idea of the current node in the list and they
53 *	access the list based on it. Because the list is circular, Lst_Next
54 *	and Lst_Prev will go around the list forever. Lst_IsAtEnd must be
55 *	used to determine when to stop.
56 */
57
58#include	"lstInt.h"
59
60/*-
61 *-----------------------------------------------------------------------
62 * Lst_IsAtEnd --
63 *	Return true if have reached the end of the given list.
64 *
65 * Results:
66 *	TRUE if at the end of the list (this includes the list not being
67 *	open or being invalid) or FALSE if not. We return TRUE if the list
68 *	is invalid or unopend so as to cause the caller to exit its loop
69 *	asap, the assumption being that the loop is of the form
70 *	    while (!Lst_IsAtEnd (l)) {
71 *	    	  ...
72 *	    }
73 *
74 * Side Effects:
75 *	None.
76 *
77 *-----------------------------------------------------------------------
78 */
79Boolean
80Lst_IsAtEnd(Lst l)
81{
82    List list = l;
83
84    return (!LstValid (l) || !list->isOpen ||
85	    (list->atEnd == Head) || (list->atEnd == Tail));
86}
87
88