xref: /netbsd/lib/libc/string/strtok_r.c (revision 6550d01e)
1 /*	$NetBSD: strtok_r.c,v 1.9 2003/08/07 16:43:53 agc 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. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char *sccsid = "@(#)strtok.c	5.8 (Berkeley) 2/24/91";
36 #else
37 __RCSID("$NetBSD: strtok_r.c,v 1.9 2003/08/07 16:43:53 agc Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include "namespace.h"
42 
43 #include <assert.h>
44 #include <string.h>
45 
46 #ifdef __weak_alias
47 __weak_alias(strtok_r,_strtok_r)
48 #endif
49 
50 char *
51 strtok_r(s, delim, lasts)
52 	char *s;
53 	const char *delim;
54 	char **lasts;
55 {
56 	const char *spanp;
57 	int c, sc;
58 	char *tok;
59 
60 	/* s may be NULL */
61 	_DIAGASSERT(delim != NULL);
62 	_DIAGASSERT(lasts != NULL);
63 
64 	if (s == NULL && (s = *lasts) == NULL)
65 		return (NULL);
66 
67 	/*
68 	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
69 	 */
70 cont:
71 	c = *s++;
72 	for (spanp = delim; (sc = *spanp++) != 0;) {
73 		if (c == sc)
74 			goto cont;
75 	}
76 
77 	if (c == 0) {		/* no non-delimiter characters */
78 		*lasts = NULL;
79 		return (NULL);
80 	}
81 	tok = s - 1;
82 
83 	/*
84 	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
85 	 * Note that delim must have one NUL; we stop if we see that, too.
86 	 */
87 	for (;;) {
88 		c = *s++;
89 		spanp = delim;
90 		do {
91 			if ((sc = *spanp++) == c) {
92 				if (c == 0)
93 					s = NULL;
94 				else
95 					s[-1] = 0;
96 				*lasts = s;
97 				return (tok);
98 			}
99 		} while (sc != 0);
100 	}
101 	/* NOTREACHED */
102 }
103