* Copyright (c) 1988, 1989, 1990, 1993
* The Regents of the University of California. All rights reserved.
* This code is derived from software contributed to Berkeley by
* %sccs.include.redist.c%
static char sccsid
[] = "@(#)lstNext.c 8.2 (Berkeley) %G%";
* Return the next node for a list.
* The sequential functions access the list in a slightly different way.
* CurPtr points to their idea of the current node in the list and they
* access the list based on it. Because the list is circular, Lst_Next
* and Lst_Prev will go around the list forever. Lst_IsAtEnd must be
* used to determine when to stop.
*-----------------------------------------------------------------------
* Return the next node for the given list.
* The next node or NILLNODE if the list has yet to be opened. Also
* if the list is non-circular and the end has been reached, NILLNODE
* the curPtr field is updated.
*-----------------------------------------------------------------------
register List list
= (List
)l
;
if ((LstValid (l
) == FALSE
) ||
(list
->isOpen
== FALSE
)) {
list
->prevPtr
= list
->curPtr
;
if (list
->curPtr
== NilListNode
) {
if (list
->atEnd
== Unknown
) {
* If we're just starting out, atEnd will be Unknown.
* Then we want to start this thing off in the right
* direction -- at the start with atEnd being Middle.
list
->curPtr
= tln
= list
->firstPtr
;
tln
= list
->curPtr
->nextPtr
;
if (tln
== list
->firstPtr
|| tln
== NilListNode
) {
* If back at the front, then we've hit the end...
* Reset to Middle if gone past first.