1 /*
2 * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Adam de Boor.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by the University of California, Berkeley. The name of the
14 * University may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 */
20
21 #ifndef lint
22 static char sccsid[] = "@(#)lstPred.c 5.2 (Berkeley) 03/11/90";
23 #endif /* not lint */
24
25 /*-
26 * LstPred.c --
27 * Return the predecessor of a given list node
28 */
29
30 #include "lstInt.h"
31
32 /*-
33 *-----------------------------------------------------------------------
34 * Lst_Pred --
35 * Return the predecessor of the given node.
36 *
37 * Results:
38 * The node's predecessor, if any, or NILLNODE if it has none.
39 *
40 * Side Effects:
41 * None.
42 *
43 *-----------------------------------------------------------------------
44 */
45 LstNode
Lst_Pred(ln)46 Lst_Pred (ln)
47 LstNode ln;
48 {
49 if (ln == NILLNODE) {
50 return (NILLNODE);
51 } else {
52 return ((LstNode)((ListNode) ln)->prevPtr);
53 }
54 }
55
56