1
/* $NetBSD: lstNext.c,v 1.12 2008/12/13 15:19:29 dsl Exp $ */
4
* Copyright (c) 1988, 1989, 1990, 1993
5
* The Regents of the University of California. All rights reserved.
7
* This code is derived from software contributed to Berkeley by
10
* Redistribution and use in source and binary forms, with or without
11
* modification, are permitted provided that the following conditions
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.
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
36
static char rcsid[] = "$NetBSD: lstNext.c,v 1.12 2008/12/13 15:19:29 dsl Exp $";
38
#include <sys/cdefs.h>
41
static char sccsid[] = "@(#)lstNext.c 8.1 (Berkeley) 6/6/93";
43
__RCSID("$NetBSD: lstNext.c,v 1.12 2008/12/13 15:19:29 dsl Exp $");
50
* Return the next node for a 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.
61
*-----------------------------------------------------------------------
63
* Return the next node for the given list.
66
* The next node or NULL if the list has yet to be opened. Also
67
* if the list is non-circular and the end has been reached, NULL
71
* the curPtr field is updated.
73
*-----------------------------------------------------------------------
81
if ((LstValid (l) == FALSE) ||
82
(list->isOpen == FALSE)) {
86
list->prevPtr = list->curPtr;
88
if (list->curPtr == NULL) {
89
if (list->atEnd == Unknown) {
91
* If we're just starting out, atEnd will be Unknown.
92
* Then we want to start this thing off in the right
93
* direction -- at the start with atEnd being Middle.
95
list->curPtr = tln = list->firstPtr;
102
tln = list->curPtr->nextPtr;
105
if (tln == list->firstPtr || tln == NULL) {
107
* If back at the front, then we've hit the end...
112
* Reset to Middle if gone past first.
114
list->atEnd = Middle;