strtok.c revision 1.3 
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 *sccsid = "from: @(#)strtok.c	5.8 (Berkeley) 2/24/91";*/
36static char *rcsid = "$Id: strtok.c,v 1.3 1993/08/26 00:52:01 jtc Exp $";
37#endif /* LIBC_SCCS and not lint */
38
39#include <stddef.h>
40#include <string.h>
41
42char *
43strtok(s, delim)
44	register char *s;
45	register const char *delim;
46{
47	register char *spanp;
48	register int c, sc;
49	char *tok;
50	static char *last;
51
52
53	if (s == NULL && (s = last) == NULL)
54		return (NULL);
55
56	/*
57	 * Skip (span) leading delimiters (s += strspn(s, delim), sort of).
58	 */
59cont:
60	c = *s++;
61	for (spanp = (char *)delim; (sc = *spanp++) != 0;) {
62		if (c == sc)
63			goto cont;
64	}
65
66	if (c == 0) {		/* no non-delimiter characters */
67		last = NULL;
68		return (NULL);
69	}
70	tok = s - 1;
71
72	/*
73	 * Scan token (scan for delimiters: s += strcspn(s, delim), sort of).
74	 * Note that delim must have one NUL; we stop if we see that, too.
75	 */
76	for (;;) {
77		c = *s++;
78		spanp = (char *)delim;
79		do {
80			if ((sc = *spanp++) == c) {
81				if (c == 0)
82					s = NULL;
83				else
84					s[-1] = 0;
85				last = s;
86				return (tok);
87			}
88		} while (sc != 0);
89	}
90	/* NOTREACHED */
91}
92