xref: /freebsd/contrib/tcpdump/missing/strsep.c (revision efe3b0de1438e7a8473d92f2be57072394559e3c)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  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 #ifdef HAVE_CONFIG_H
35 #include <config.h>
36 #endif
37 
38 #include <netdissect-stdinc.h>
39 
40 #include <string.h>
41 
42 #include "netdissect.h"
43 
44 /*
45  * Get next token from string *stringp, where tokens are possibly-empty
46  * strings separated by characters from delim.
47  *
48  * Writes NULs into the string at *stringp to end tokens.
49  * delim need not remain constant from call to call.
50  * On return, *stringp points past the last NUL written (if there might
51  * be further tokens), or is NULL (if there are definitely no more tokens).
52  *
53  * If *stringp is NULL, strsep returns NULL.
54  */
55 char *
56 strsep(char **stringp, const char *delim)
57 {
58 	register char *s;
59 	register const char *spanp;
60 	register int c, sc;
61 	char *tok;
62 
63 	if ((s = *stringp) == NULL)
64 		return (NULL);
65 	for (tok = s;;) {
66 		c = *s++;
67 		spanp = delim;
68 		do {
69 			if ((sc = *spanp++) == c) {
70 				if (c == 0)
71 					s = NULL;
72 				else
73 					s[-1] = 0;
74 				*stringp = s;
75 				return (tok);
76 			}
77 		} while (sc != 0);
78 	}
79 	/* NOTREACHED */
80 }
81