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 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)strstr.c 8.1 (Berkeley) 6/4/93 38 * $FreeBSD: src/lib/libc/string/strnstr.c,v 1.2.2.1 2001/12/09 06:50:03 mike Exp $ 39 * $DragonFly: src/lib/libc/string/strnstr.c,v 1.4 2006/03/20 17:24:20 dillon Exp $ 40 */ 41 42 #include <sys/types.h> 43 #include <string.h> 44 45 /* 46 * Find the first occurrence of find in s, where the search is limited to the 47 * first slen characters of s. 48 */ 49 char * 50 strnstr(const char *s, const char *find, size_t slen) 51 { 52 char c, sc; 53 size_t len; 54 55 if ((c = *find++) != '\0') { 56 len = strlen(find); 57 do { 58 do { 59 if (slen < 1 || (sc = *s) == '\0') 60 return (NULL); 61 --slen; 62 ++s; 63 } while (sc != c); 64 if (len > slen) 65 return (NULL); 66 } while (strncmp(s, find, len) != 0); 67 s--; 68 } 69 return (__DECONST(char *, s)); 70 } 71