xref: /freebsd/lib/libc/string/strsep.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
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 #include <string.h>
37 #include <stdio.h>
38 
39 /*
40  * Get next token from string *stringp, where tokens are possibly-empty
41  * strings separated by characters from delim.
42  *
43  * Writes NULs into the string at *stringp to end tokens.
44  * delim need not remain constant from call to call.
45  * On return, *stringp points past the last NUL written (if there might
46  * be further tokens), or is NULL (if there are definitely no more tokens).
47  *
48  * If *stringp is NULL, strsep returns NULL.
49  */
50 char *
51 strsep(char **stringp, const char *delim)
52 {
53 	char *s;
54 	const char *spanp;
55 	int c, sc;
56 	char *tok;
57 
58 	if ((s = *stringp) == NULL)
59 		return (NULL);
60 	for (tok = s;;) {
61 		c = *s++;
62 		spanp = delim;
63 		do {
64 			if ((sc = *spanp++) == c) {
65 				if (c == 0)
66 					s = NULL;
67 				else
68 					s[-1] = 0;
69 				*stringp = s;
70 				return (tok);
71 			}
72 		} while (sc != 0);
73 	}
74 	/* NOTREACHED */
75 }
76