strtok.c revision 1.9 
1/*	$NetBSD: strtok.c,v 1.9 1999/09/16 11:45:43 lukem 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. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include <sys/cdefs.h>
37#if defined(LIBC_SCCS) && !defined(lint)
38#if 0
39static char sccsid[] = "@(#)strtok.c	8.1 (Berkeley) 6/4/93";
40#else
41__RCSID("$NetBSD: strtok.c,v 1.9 1999/09/16 11:45:43 lukem Exp $");
42#endif
43#endif /* LIBC_SCCS and not lint */
44
45#include <assert.h>
46#include <string.h>
47
48char *
49strtok(s, delim)
50	char *s;
51	const char *delim;
52{
53	const char *spanp;
54	int c, sc;
55	char *tok;
56	static char *last;
57
58	/* s may be NULL */
59	_DIAGASSERT(delim != NULL);
60#ifdef _DIAGNOSTIC
61	if (delim == NULL)
62		return (NULL);
63#endif
64
65	if (s == NULL && (s = last) == NULL)
66		return (NULL);
67
68	/*
69	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
70	 */
71cont:
72	c = *s++;
73	for (spanp = delim; (sc = *spanp++) != 0;) {
74		if (c == sc)
75			goto cont;
76	}
77
78	if (c == 0) {		/* no non-delimiter characters */
79		last = NULL;
80		return (NULL);
81	}
82	tok = s - 1;
83
84	/*
85	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
86	 * Note that delim must have one NUL; we stop if we see that, too.
87	 */
88	for (;;) {
89		c = *s++;
90		spanp = delim;
91		do {
92			if ((sc = *spanp++) == c) {
93				if (c == 0)
94					s = NULL;
95				else
96					s[-1] = 0;
97				last = s;
98				return (tok);
99			}
100		} while (sc != 0);
101	}
102	/* NOTREACHED */
103}
104