xref: /freebsd/lib/libc/amd64/string/strnlen.c (revision 559a218c9b257775fb249b67945fe4a05b7a6b9f)
1*33173728SRobert Clausecker /*-
2*33173728SRobert Clausecker  * Copyright (c) 2023 The FreeBSD Foundation
3*33173728SRobert Clausecker  *
4*33173728SRobert Clausecker  * This software was developed by Robert Clausecker <fuz@FreeBSD.org>
5*33173728SRobert Clausecker  * under sponsorship from the FreeBSD Foundation.
6*33173728SRobert Clausecker  *
7*33173728SRobert Clausecker  * Redistribution and use in source and binary forms, with or without
8*33173728SRobert Clausecker  * modification, are permitted provided that the following conditions
9*33173728SRobert Clausecker  * are met:
10*33173728SRobert Clausecker  * 1. Redistributions of source code must retain the above copyright
11*33173728SRobert Clausecker  *    notice, this list of conditions and the following disclaimer.
12*33173728SRobert Clausecker  * 2. Redistributions in binary form must reproduce the above copyright
13*33173728SRobert Clausecker  *    notice, this list of conditions and the following disclaimer in the
14*33173728SRobert Clausecker  *    documentation and/or other materials provided with the distribution.
15*33173728SRobert Clausecker  *
16*33173728SRobert Clausecker  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ''AS IS'' AND
17*33173728SRobert Clausecker  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18*33173728SRobert Clausecker  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19*33173728SRobert Clausecker  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20*33173728SRobert Clausecker  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21*33173728SRobert Clausecker  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22*33173728SRobert Clausecker  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23*33173728SRobert Clausecker  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24*33173728SRobert Clausecker  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25*33173728SRobert Clausecker  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26*33173728SRobert Clausecker  * SUCH DAMAGE
27*33173728SRobert Clausecker  */
28*33173728SRobert Clausecker 
29*33173728SRobert Clausecker #include <string.h>
30*33173728SRobert Clausecker 
31*33173728SRobert Clausecker char *__memchr(const void *, int, size_t);
32*33173728SRobert Clausecker 
33*33173728SRobert Clausecker size_t
strnlen(const char * s,size_t maxlen)34*33173728SRobert Clausecker strnlen(const char *s, size_t maxlen)
35*33173728SRobert Clausecker {
36*33173728SRobert Clausecker 	const char *loc;
37*33173728SRobert Clausecker 
38*33173728SRobert Clausecker 	loc = __memchr(s, '\0', maxlen);
39*33173728SRobert Clausecker 
40*33173728SRobert Clausecker 	return (loc == NULL ? maxlen : (size_t)(loc - s));
41*33173728SRobert Clausecker }
42