141036d78SMike Barcroft /*-
2*8a16b7a1SPedro F. Giffuni * SPDX-License-Identifier: BSD-3-Clause
3*8a16b7a1SPedro F. Giffuni *
441036d78SMike Barcroft * Copyright (c) 2001 Mike Barcroft <mike@FreeBSD.org>
541036d78SMike Barcroft * Copyright (c) 1990, 1993
641036d78SMike Barcroft * The Regents of the University of California. All rights reserved.
741036d78SMike Barcroft *
841036d78SMike Barcroft * This code is derived from software contributed to Berkeley by
941036d78SMike Barcroft * Chris Torek.
1041036d78SMike Barcroft *
1141036d78SMike Barcroft * Redistribution and use in source and binary forms, with or without
1241036d78SMike Barcroft * modification, are permitted provided that the following conditions
1341036d78SMike Barcroft * are met:
1441036d78SMike Barcroft * 1. Redistributions of source code must retain the above copyright
1541036d78SMike Barcroft * notice, this list of conditions and the following disclaimer.
1641036d78SMike Barcroft * 2. Redistributions in binary form must reproduce the above copyright
1741036d78SMike Barcroft * notice, this list of conditions and the following disclaimer in the
1841036d78SMike Barcroft * documentation and/or other materials provided with the distribution.
193fb3b97cSEd Maste * 3. Neither the name of the University nor the names of its contributors
2041036d78SMike Barcroft * may be used to endorse or promote products derived from this software
2141036d78SMike Barcroft * without specific prior written permission.
2241036d78SMike Barcroft *
2341036d78SMike Barcroft * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
2441036d78SMike Barcroft * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
2541036d78SMike Barcroft * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
2641036d78SMike Barcroft * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
2741036d78SMike Barcroft * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
2841036d78SMike Barcroft * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
2941036d78SMike Barcroft * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
3041036d78SMike Barcroft * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
3141036d78SMike Barcroft * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
3241036d78SMike Barcroft * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
3341036d78SMike Barcroft * SUCH DAMAGE.
3441036d78SMike Barcroft */
3541036d78SMike Barcroft
3641036d78SMike Barcroft #include <string.h>
3741036d78SMike Barcroft
3841036d78SMike Barcroft /*
3941036d78SMike Barcroft * Find the first occurrence of find in s, where the search is limited to the
4041036d78SMike Barcroft * first slen characters of s.
4141036d78SMike Barcroft */
4241036d78SMike Barcroft char *
strnstr(const char * s,const char * find,size_t slen)43bd604b4bSDaniel Gerzo strnstr(const char *s, const char *find, size_t slen)
4441036d78SMike Barcroft {
4541036d78SMike Barcroft char c, sc;
4641036d78SMike Barcroft size_t len;
4741036d78SMike Barcroft
4841036d78SMike Barcroft if ((c = *find++) != '\0') {
4941036d78SMike Barcroft len = strlen(find);
5041036d78SMike Barcroft do {
5141036d78SMike Barcroft do {
52029f08c2SPawel Jakub Dawidek if (slen-- < 1 || (sc = *s++) == '\0')
5341036d78SMike Barcroft return (NULL);
5441036d78SMike Barcroft } while (sc != c);
5541036d78SMike Barcroft if (len > slen)
5641036d78SMike Barcroft return (NULL);
5741036d78SMike Barcroft } while (strncmp(s, find, len) != 0);
5841036d78SMike Barcroft s--;
5941036d78SMike Barcroft }
6041036d78SMike Barcroft return ((char *)s);
6141036d78SMike Barcroft }
62