xref: /dragonfly/lib/libc/string/wcsstr.c (revision dc71b7ab)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Chris Torek.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  * @(#)strstr.c	8.1 (Berkeley) 6/4/93
33  * $FreeBSD: src/lib/libc/string/wcsstr.c,v 1.9 2007/01/09 00:28:12 imp Exp $
34  * $DragonFly: src/lib/libc/string/wcsstr.c,v 1.3 2005/04/28 13:25:12 joerg Exp $
35  */
36 
37 #include <sys/types.h>
38 #include <wchar.h>
39 
40 /*
41  * Find the first occurrence of find in s.
42  */
43 wchar_t *
44 wcsstr(const wchar_t * __restrict s, const wchar_t * __restrict find)
45 {
46 	wchar_t c, sc;
47 	size_t len;
48 
49 	if ((c = *find++) != 0) {
50 		len = wcslen(find);
51 		do {
52 			do {
53 				if ((sc = *s++) == L'\0')
54 					return (NULL);
55 			} while (sc != c);
56 		} while (wcsncmp(s, find, len) != 0);
57 		s--;
58 	}
59 	return (__DECONST(wchar_t *, s));
60 }
61