xref: /freebsd/lib/libc/string/strsep.c (revision 0b57cec536236d46e3dba9bd041533462f33dbb7)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1990, 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 #if defined(LIBC_SCCS) && !defined(lint)
33 static char sccsid[] = "@(#)strsep.c	8.1 (Berkeley) 6/4/93";
34 #endif /* LIBC_SCCS and not lint */
35 #include <sys/cdefs.h>
36 __FBSDID("$FreeBSD$");
37 
38 #include <string.h>
39 #include <stdio.h>
40 
41 /*
42  * Get next token from string *stringp, where tokens are possibly-empty
43  * strings separated by characters from delim.
44  *
45  * Writes NULs into the string at *stringp to end tokens.
46  * delim need not remain constant from call to call.
47  * On return, *stringp points past the last NUL written (if there might
48  * be further tokens), or is NULL (if there are definitely no more tokens).
49  *
50  * If *stringp is NULL, strsep returns NULL.
51  */
52 char *
53 strsep(char **stringp, const char *delim)
54 {
55 	char *s;
56 	const char *spanp;
57 	int c, sc;
58 	char *tok;
59 
60 	if ((s = *stringp) == NULL)
61 		return (NULL);
62 	for (tok = s;;) {
63 		c = *s++;
64 		spanp = delim;
65 		do {
66 			if ((sc = *spanp++) == c) {
67 				if (c == 0)
68 					s = NULL;
69 				else
70 					s[-1] = 0;
71 				*stringp = s;
72 				return (tok);
73 			}
74 		} while (sc != 0);
75 	}
76 	/* NOTREACHED */
77 }
78