xref: /csrg-svn/lib/libc/string/strtok.c (revision 34831)
1 /*
2  * Copyright (c) 1985 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #if defined(LIBC_SCCS) && !defined(lint)
19 static char sccsid[] = "@(#)strtok.c	5.4 (Berkeley) 06/27/88";
20 #endif /* LIBC_SCCS and not lint */
21 
22 char *
23 strtok(s, sep)
24 	register char *s, *sep;
25 {
26 	register char *p;
27 	register c;
28 	static char *lasts;
29 
30 	if (s == 0)
31 		s = lasts;
32 	if (s == 0)
33 		return (0);
34 
35 	while (c = *s) {
36 		if (!index(sep, c))
37 			break;
38 		s++;
39 	}
40 
41 	if (c == '\0') {
42 		lasts = 0;
43 		return (0);
44 	}
45 
46 	for (p = s; c = *++p; )
47 		if (index(sep, c))
48 			break;
49 
50 	if (c == '\0')
51 		lasts = 0;
52 	else {
53 		*p++ = '\0';
54 		lasts = p;
55 	}
56 	return (s);
57 }
58