xref: /netbsd-src/common/lib/libc/string/strsep.c (revision c0179c282a5968435315a82f4128c61372c68fc3)
1 /*	$NetBSD: strsep.c,v 1.1 2006/11/13 03:26:43 dyoung Exp $	*/
2 
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 #include <sys/cdefs.h>
33 #if defined(LIBC_SCCS) && !defined(lint)
34 #if 0
35 static char sccsid[] = "@(#)strsep.c	8.1 (Berkeley) 6/4/93";
36 #else
37 __RCSID("$NetBSD: strsep.c,v 1.1 2006/11/13 03:26:43 dyoung Exp $");
38 #endif
39 #endif /* LIBC_SCCS and not lint */
40 
41 #if !defined(_KERNEL) && !defined(_STANDALONE)
42 #include "namespace.h"
43 
44 #include <assert.h>
45 #include <string.h>
46 #else
47 #include <sys/param.h>
48 #include <lib/libkern/libkern.h>
49 #endif
50 
51 #ifdef __weak_alias
52 __weak_alias(strsep,_strsep)
53 #endif
54 
55 #if !HAVE_STRSEP
56 /*
57  * Get next token from string *stringp, where tokens are possibly-empty
58  * strings separated by characters from delim.
59  *
60  * Writes NULs into the string at *stringp to end tokens.
61  * delim need not remain constant from call to call.
62  * On return, *stringp points past the last NUL written (if there might
63  * be further tokens), or is NULL (if there are definitely no more tokens).
64  *
65  * If *stringp is NULL, strsep returns NULL.
66  */
67 char *
68 strsep(stringp, delim)
69 	char **stringp;
70 	const char *delim;
71 {
72 	char *s;
73 	const char *spanp;
74 	int c, sc;
75 	char *tok;
76 
77 	_DIAGASSERT(stringp != NULL);
78 	_DIAGASSERT(delim != NULL);
79 
80 	if ((s = *stringp) == NULL)
81 		return (NULL);
82 	for (tok = s;;) {
83 		c = *s++;
84 		spanp = delim;
85 		do {
86 			if ((sc = *spanp++) == c) {
87 				if (c == 0)
88 					s = NULL;
89 				else
90 					s[-1] = 0;
91 				*stringp = s;
92 				return (tok);
93 			}
94 		} while (sc != 0);
95 	}
96 	/* NOTREACHED */
97 }
98 #endif
99