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[] = "@(#)lstIndex.c	5.2 (Berkeley) 03/11/90";
23 #endif /* not lint */
24 
25 /*-
26  * lstIndex.c --
27  *	Function to return the index of a datum in a Lst.
28  */
29 
30 #include    "lstInt.h"
31 
32 /*-
33  *-----------------------------------------------------------------------
34  * Lst_Index --
35  *	Return the index of a datum in a Lst. Indices start at 0.
36  *
37  * Results:
38  *	Returns -1 if the datum isn't in the Lst, or the index of
39  *	the datum if it is.
40  *
41  * Side Effects:
42  *	None.
43  *
44  *-----------------------------------------------------------------------
45  */
46 int
47 Lst_Index(l, d)
48     Lst	    	  	l;
49     ClientData	  	d;
50 {
51     List    	  	list = (List)l;
52     register ListNode	lNode;
53     register int  	index;
54 
55     lNode = list->firstPtr;
56 
57     if (lNode == NilListNode) {
58 	return(-1);
59     }
60 
61     index = 0;
62 
63     do {
64 	if (lNode->datum == d) {
65 	    return(index);
66 	} else {
67 	    lNode = lNode->nextPtr;
68 	    index += 1;
69 	}
70     } while (lNode != NilListNode && lNode != list->firstPtr);
71     return(-1);
72 }
73