1 /*	$OpenBSD: strsep.c,v 1.8 2015/08/31 02:53:57 guenther 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 <string.h>
33 
34 #include "compat.h"
35 
36 /*
37  * Get next token from string *stringp, where tokens are possibly-empty
38  * strings separated by characters from delim.  
39  *
40  * Writes NULs into the string at *stringp to end tokens.
41  * delim need not remain constant from call to call.
42  * On return, *stringp points past the last NUL written (if there might
43  * be further tokens), or is NULL (if there are definitely no more tokens).
44  *
45  * If *stringp is NULL, strsep returns NULL.
46  */
47 char *
48 strsep(char **stringp, const char *delim)
49 {
50 	char *s;
51 	const char *spanp;
52 	int c, sc;
53 	char *tok;
54 
55 	if ((s = *stringp) == NULL)
56 		return (NULL);
57 	for (tok = s;;) {
58 		c = *s++;
59 		spanp = delim;
60 		do {
61 			if ((sc = *spanp++) == c) {
62 				if (c == 0)
63 					s = NULL;
64 				else
65 					s[-1] = 0;
66 				*stringp = s;
67 				return (tok);
68 			}
69 		} while (sc != 0);
70 	}
71 	/* NOTREACHED */
72 }