1 /*- 2 * Copyright (c) 2005 Pascal Gloor <pascal.gloor@spale.com> 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. The name of the author may not be used to endorse or promote 13 * products derived from this software without specific prior written 14 * permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <string.h> 33 34 /* 35 * Find the first occurrence of the byte string s in byte string l. 36 */ 37 38 void * 39 memmem(l, l_len, s, s_len) 40 const void *l; size_t l_len; 41 const void *s; size_t s_len; 42 { 43 register char *cur, *last; 44 const char *cl = (const char *)l; 45 const char *cs = (const char *)s; 46 47 /* we need something to compare */ 48 if (l_len == 0 || s_len == 0) 49 return NULL; 50 51 /* "s" must be smaller or equal to "l" */ 52 if (l_len < s_len) 53 return NULL; 54 55 /* special case where s_len == 1 */ 56 if (s_len == 1) 57 return memchr(l, (int)*cs, l_len); 58 59 /* the last position where its possible to find "s" in "l" */ 60 last = (char *)cl + l_len - s_len; 61 62 for (cur = (char *)cl; cur <= last; cur++) 63 if (cur[0] == cs[0] && memcmp(cur, cs, s_len) == 0) 64 return cur; 65 66 return NULL; 67 } 68