1*40412Sbostic /*
2*40412Sbostic * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
3*40412Sbostic * All rights reserved.
440411Sbostic *
5*40412Sbostic * This code is derived from software contributed to Berkeley by
6*40412Sbostic * Adam de Boor.
740411Sbostic *
8*40412Sbostic * Redistribution and use in source and binary forms are permitted
9*40412Sbostic * provided that the above copyright notice and this paragraph are
10*40412Sbostic * duplicated in all such forms and that any documentation,
11*40412Sbostic * advertising materials, and other materials related to such
12*40412Sbostic * distribution and use acknowledge that the software was developed
13*40412Sbostic * by the University of California, Berkeley. The name of the
14*40412Sbostic * University may not be used to endorse or promote products derived
15*40412Sbostic * from this software without specific prior written permission.
16*40412Sbostic * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17*40412Sbostic * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18*40412Sbostic * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
1940411Sbostic */
20*40412Sbostic
2140411Sbostic #ifndef lint
22*40412Sbostic static char sccsid[] = "@(#)lstSetCirc.c 5.2 (Berkeley) 03/11/90";
23*40412Sbostic #endif /* not lint */
2440411Sbostic
25*40412Sbostic /*-
26*40412Sbostic * listSetCirc.c --
27*40412Sbostic * Change the library's notion of the circularity of a list.
28*40412Sbostic */
29*40412Sbostic
3040411Sbostic #include "lstInt.h"
3140411Sbostic
3240411Sbostic /*
3340411Sbostic *------------------------------------------------------------
3440411Sbostic * Lst_SetCirc --
3540411Sbostic * change the circularity of a list
3640411Sbostic *
3740411Sbostic * Results:
3840411Sbostic * none
3940411Sbostic *
4040411Sbostic * Side Effects:
4140411Sbostic * The circularity of the list is set appropriately. The head and
4240411Sbostic * tail of the list will be linked or unlinked as necessary
4340411Sbostic *------------------------------------------------------------
4440411Sbostic */
4540411Sbostic void
Lst_SetCirc(l,circ)4640411Sbostic Lst_SetCirc (l, circ)
4740411Sbostic Lst l;
4840411Sbostic Boolean circ;
4940411Sbostic {
5040411Sbostic register List list = (List) l;
5140411Sbostic
5240411Sbostic /*
5340411Sbostic * if this isn't a change, do nothing.
5440411Sbostic */
5540411Sbostic if ((list->isCirc && circ) || (!list->isCirc && !circ)) {
5640411Sbostic return;
5740411Sbostic }
5840411Sbostic list->isCirc = circ;
5940411Sbostic
6040411Sbostic if (LstIsEmpty (l)) {
6140411Sbostic return;
6240411Sbostic }
6340411Sbostic
6440411Sbostic if (circ) {
6540411Sbostic list->firstPtr->prevPtr = list->lastPtr;
6640411Sbostic list->lastPtr->nextPtr = list->firstPtr;
6740411Sbostic } else {
6840411Sbostic list->firstPtr->prevPtr = NilListNode;
6940411Sbostic list->lastPtr->nextPtr = NilListNode;
7040411Sbostic }
7140411Sbostic }
72