xref: /original-bsd/lib/libc/string/strcspn.c (revision e0c0d005)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Chris Torek.
7  *
8  * %sccs.include.redist.c%
9  */
10 
11 #if defined(LIBC_SCCS) && !defined(lint)
12 static char sccsid[] = "@(#)strcspn.c	5.6 (Berkeley) 01/26/91";
13 #endif /* LIBC_SCCS and not lint */
14 
15 #include <sys/cdefs.h>
16 #include <string.h>
17 
18 /*
19  * Span the complement of string s2.
20  */
21 size_t
22 strcspn(s1, s2)
23 	const char *s1;
24 	register const char *s2;
25 {
26 	register const char *p, *spanp;
27 	register char c, sc;
28 
29 	/*
30 	 * Stop as soon as we find any character from s2.  Note that there
31 	 * must be a NUL in s2; it suffices to stop when we find that, too.
32 	 */
33 	for (p = s1;;) {
34 		c = *p++;
35 		spanp = s2;
36 		do {
37 			if ((sc = *spanp++) == c)
38 				return (p - 1 - s1);
39 		} while (sc != 0);
40 	}
41 	/* NOTREACHED */
42 }
43