1 /*- 2 * Copyright (c) 2001 Mike Barcroft <mike@FreeBSD.org> 3 * Copyright (c) 1990, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * Chris Torek. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)strstr.c 8.1 (Berkeley) 6/4/93 34 * $FreeBSD: src/lib/libc/string/strnstr.c,v 1.4 2007/01/09 00:28:12 imp Exp $ 35 * $DragonFly: src/lib/libc/string/strnstr.c,v 1.4 2006/03/20 17:24:20 dillon Exp $ 36 */ 37 38 #include <sys/types.h> 39 #include <string.h> 40 41 /* 42 * Find the first occurrence of find in s, where the search is limited to the 43 * first slen characters of s. 44 */ 45 char * 46 strnstr(const char *s, const char *find, size_t slen) 47 { 48 char c, sc; 49 size_t len; 50 51 if ((c = *find++) != '\0') { 52 len = strlen(find); 53 do { 54 do { 55 if (slen < 1 || (sc = *s) == '\0') 56 return (NULL); 57 --slen; 58 ++s; 59 } while (sc != c); 60 if (len > slen) 61 return (NULL); 62 } while (strncmp(s, find, len) != 0); 63 s--; 64 } 65 return (__DECONST(char *, s)); 66 } 67