xref: /freebsd/contrib/mandoc/compat_strsep.c (revision 59c8e88e72633afbc47a4ace0d2170d00d51f7dc)
1 /*	$Id: compat_strsep.c,v 1.5 2020/06/15 01:37:15 schwarze Exp $	*/
2 /*	$OpenBSD: strsep.c,v 1.8 2015/08/31 02:53:57 guenther Exp $	*/
3 
4 /*-
5  * Copyright (c) 1990, 1993
6  *	The Regents of the University of California.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 #include "config.h"
33 
34 /*
35  * Get next token from string *stringp, where tokens are possibly-empty
36  * strings separated by characters from delim.
37  *
38  * Writes NULs into the string at *stringp to end tokens.
39  * delim need not remain constant from call to call.
40  * On return, *stringp points past the last NUL written (if there might
41  * be further tokens), or is NULL (if there are definitely no more tokens).
42  *
43  * If *stringp is NULL, strsep returns NULL.
44  */
45 char *
46 strsep(char **stringp, const char *delim)
47 {
48 	char *s;
49 	const char *spanp;
50 	int c, sc;
51 	char *tok;
52 
53 	if ((s = *stringp) == NULL)
54 		return (NULL);
55 	for (tok = s;;) {
56 		c = *s++;
57 		spanp = delim;
58 		do {
59 			if ((sc = *spanp++) == c) {
60 				if (c == 0)
61 					s = NULL;
62 				else
63 					s[-1] = 0;
64 				*stringp = s;
65 				return (tok);
66 			}
67 		} while (sc != 0);
68 	}
69 	/* NOTREACHED */
70 }
71