xref: /openbsd-src/lib/libc/string/strtok.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
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 *rcsid = "$OpenBSD: strtok.c,v 1.3 1999/11/09 11:19:46 art Exp $";
36 #endif /* LIBC_SCCS and not lint */
37 
38 #include <string.h>
39 
40 char *
41 strtok(s, delim)
42 	register char *s;
43 	register const char *delim;
44 {
45 	static char *last;
46 
47 	return strtok_r(s, delim, &last);
48 }
49 
50 char *
51 strtok_r(s, delim, last)
52 	register char *s;
53 	register const char *delim;
54 	char **last;
55 {
56 	register char *spanp;
57 	register int c, sc;
58 	char *tok;
59 
60 
61 	if (s == NULL && (s = *last) == NULL)
62 		return (NULL);
63 
64 	/*
65 	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
66 	 */
67 cont:
68 	c = *s++;
69 	for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
70 		if (c == sc)
71 			goto cont;
72 	}
73 
74 	if (c == 0) {		/* no non-delimiter characters */
75 		*last = NULL;
76 		return (NULL);
77 	}
78 	tok = s - 1;
79 
80 	/*
81 	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
82 	 * Note that delim must have one NUL; we stop if we see that, too.
83 	 */
84 	for (;;) {
85 		c = *s++;
86 		spanp = (char *)delim;
87 		do {
88 			if ((sc = *spanp++) == c) {
89 				if (c == 0)
90 					s = NULL;
91 				else
92 					s[-1] = 0;
93 				*last = s;
94 				return (tok);
95 			}
96 		} while (sc != 0);
97 	}
98 	/* NOTREACHED */
99 }
100