xref: /netbsd-src/lib/libc/string/strtok.c (revision 0b9f50897e9a9c6709320fafb4c3787fddcc0a45)
1 /*
2  * Copyright (c) 1988 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 /*static char *sccsid = "from: @(#)strtok.c	5.8 (Berkeley) 2/24/91";*/
36 static char *rcsid = "$Id: strtok.c,v 1.3 1993/08/26 00:52:01 jtc Exp $";
37 #endif /* LIBC_SCCS and not lint */
38 
39 #include <stddef.h>
40 #include <string.h>
41 
42 char *
43 strtok(s, delim)
44 	register char *s;
45 	register const char *delim;
46 {
47 	register char *spanp;
48 	register int c, sc;
49 	char *tok;
50 	static char *last;
51 
52 
53 	if (s == NULL && (s = last) == NULL)
54 		return (NULL);
55 
56 	/*
57 	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
58 	 */
59 cont:
60 	c = *s++;
61 	for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
62 		if (c == sc)
63 			goto cont;
64 	}
65 
66 	if (c == 0) {		/* no non-delimiter characters */
67 		last = NULL;
68 		return (NULL);
69 	}
70 	tok = s - 1;
71 
72 	/*
73 	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
74 	 * Note that delim must have one NUL; we stop if we see that, too.
75 	 */
76 	for (;;) {
77 		c = *s++;
78 		spanp = (char *)delim;
79 		do {
80 			if ((sc = *spanp++) == c) {
81 				if (c == 0)
82 					s = NULL;
83 				else
84 					s[-1] = 0;
85 				last = s;
86 				return (tok);
87 			}
88 		} while (sc != 0);
89 	}
90 	/* NOTREACHED */
91 }
92