xref: /netbsd-src/lib/libc/string/strtok.c (revision 2a399c6883d870daece976daec6ffa7bb7f934ce)
1 /*	$NetBSD: strtok.c,v 1.5 1997/07/13 20:24:35 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 1988 Regents of the University of California.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. Neither the name of the University nor the names of its contributors
20  *    may be used to endorse or promote products derived from this software
21  *    without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33  * SUCH DAMAGE.
34  */
35 
36 #include <sys/cdefs.h>
37 #if defined(LIBC_SCCS) && !defined(lint)
38 #if 0
39 static char *sccsid = "@(#)strtok.c	5.8 (Berkeley) 2/24/91";
40 #else
41 __RCSID("$NetBSD: strtok.c,v 1.5 1997/07/13 20:24:35 christos Exp $");
42 #endif
43 #endif /* LIBC_SCCS and not lint */
44 
45 #include <string.h>
46 
47 char *
48 strtok(s, delim)
49 	register char *s;
50 	register const char *delim;
51 {
52 	register char *spanp;
53 	register int c, sc;
54 	char *tok;
55 	static char *last;
56 
57 
58 	if (s == NULL && (s = last) == NULL)
59 		return (NULL);
60 
61 	/*
62 	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
63 	 */
64 cont:
65 	c = *s++;
66 	for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
67 		if (c == sc)
68 			goto cont;
69 	}
70 
71 	if (c == 0) {		/* no non-delimiter characters */
72 		last = NULL;
73 		return (NULL);
74 	}
75 	tok = s - 1;
76 
77 	/*
78 	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
79 	 * Note that delim must have one NUL; we stop if we see that, too.
80 	 */
81 	for (;;) {
82 		c = *s++;
83 		spanp = (char *)delim;
84 		do {
85 			if ((sc = *spanp++) == c) {
86 				if (c == 0)
87 					s = NULL;
88 				else
89 					s[-1] = 0;
90 				last = s;
91 				return (tok);
92 			}
93 		} while (sc != 0);
94 	}
95 	/* NOTREACHED */
96 }
97