xref: /openbsd-src/lib/libc/string/strtok.c (revision db3296cf5c1dd9058ceecc3a29fe4aaa0bd26000)
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. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char *rcsid = "$OpenBSD: strtok.c,v 1.5 2003/06/11 21:08:16 deraadt Exp $";
32 #endif /* LIBC_SCCS and not lint */
33 
34 #include <string.h>
35 
36 char *
37 strtok(char *s, const char *delim)
38 {
39 	static char *last;
40 
41 	return strtok_r(s, delim, &last);
42 }
43 
44 char *
45 strtok_r(char *s, const char *delim, char **last)
46 {
47 	char *spanp;
48 	int c, sc;
49 	char *tok;
50 
51 
52 	if (s == NULL && (s = *last) == NULL)
53 		return (NULL);
54 
55 	/*
56 	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
57 	 */
58 cont:
59 	c = *s++;
60 	for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
61 		if (c == sc)
62 			goto cont;
63 	}
64 
65 	if (c == 0) {		/* no non-delimiter characters */
66 		*last = NULL;
67 		return (NULL);
68 	}
69 	tok = s - 1;
70 
71 	/*
72 	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
73 	 * Note that delim must have one NUL; we stop if we see that, too.
74 	 */
75 	for (;;) {
76 		c = *s++;
77 		spanp = (char *)delim;
78 		do {
79 			if ((sc = *spanp++) == c) {
80 				if (c == 0)
81 					s = NULL;
82 				else
83 					s[-1] = 0;
84 				*last = s;
85 				return (tok);
86 			}
87 		} while (sc != 0);
88 	}
89 	/* NOTREACHED */
90 }
91