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36 * $FreeBSD: src/usr.bin/make/lst.lib/lstNext.c,v 1.6 1999/08/28 01:03:55 peter Exp $
37 * $DragonFly: src/usr.bin/make/lst.lib/Attic/lstNext.c,v 1.2 2003/06/17 04:29:29 dillon Exp $
39 * @(#)lstNext.c 8.1 (Berkeley) 6/6/93
44 * Return the next node for a list.
45 * The sequential functions access the list in a slightly different way.
46 * CurPtr points to their idea of the current node in the list and they
47 * access the list based on it. Because the list is circular, Lst_Next
48 * and Lst_Prev will go around the list forever. Lst_IsAtEnd must be
49 * used to determine when to stop.
55 *-----------------------------------------------------------------------
57 * Return the next node for the given list.
60 * The next node or NILLNODE if the list has yet to be opened. Also
61 * if the list is non-circular and the end has been reached, NILLNODE
65 * the curPtr field is updated.
67 *-----------------------------------------------------------------------
73 register ListNode tln;
74 register List list = (List)l;
76 if ((LstValid (l) == FALSE) ||
77 (list->isOpen == FALSE)) {
81 list->prevPtr = list->curPtr;
83 if (list->curPtr == NilListNode) {
84 if (list->atEnd == Unknown) {
86 * If we're just starting out, atEnd will be Unknown.
87 * Then we want to start this thing off in the right
88 * direction -- at the start with atEnd being Middle.
90 list->curPtr = tln = list->firstPtr;
97 tln = list->curPtr->nextPtr;
100 if (tln == list->firstPtr || tln == NilListNode) {
102 * If back at the front, then we've hit the end...
107 * Reset to Middle if gone past first.
109 list->atEnd = Middle;
113 return ((LstNode)tln);