strtok.c revision 1.11 
1/*	$NetBSD: strtok.c,v 1.11 2003/08/07 16:43:53 agc Exp $	*/
2
3/*
4 * Copyright (c) 1988, 1993
5 *	The Regents of the University of California.  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
35static char sccsid[] = "@(#)strtok.c	8.1 (Berkeley) 6/4/93";
36#else
37__RCSID("$NetBSD: strtok.c,v 1.11 2003/08/07 16:43:53 agc Exp $");
38#endif
39#endif /* LIBC_SCCS and not lint */
40
41#include <assert.h>
42#include <string.h>
43
44char *
45strtok(s, delim)
46	char *s;
47	const char *delim;
48{
49	const char *spanp;
50	int c, sc;
51	char *tok;
52	static char *last;
53
54	/* s may be NULL */
55	_DIAGASSERT(delim != NULL);
56
57	if (s == NULL && (s = last) == NULL)
58		return (NULL);
59
60	/*
61	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
62	 */
63cont:
64	c = *s++;
65	for (spanp = delim; (sc = *spanp++) != 0;) {
66		if (c == sc)
67			goto cont;
68	}
69
70	if (c == 0) {		/* no non-delimiter characters */
71		last = NULL;
72		return (NULL);
73	}
74	tok = s - 1;
75
76	/*
77	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
78	 * Note that delim must have one NUL; we stop if we see that, too.
79	 */
80	for (;;) {
81		c = *s++;
82		spanp = delim;
83		do {
84			if ((sc = *spanp++) == c) {
85				if (c == 0)
86					s = NULL;
87				else
88					s[-1] = 0;
89				last = s;
90				return (tok);
91			}
92		} while (sc != 0);
93	}
94	/* NOTREACHED */
95}
96