compat/strcasestr.c

   1 /*      $OpenBSD: strcasestr.c,v 1.3 2006/03/31 05:34:55 deraadt Exp $  */
   2 /*      $NetBSD: strcasestr.c,v 1.2 2005/02/09 21:35:47 kleink Exp $    */
   3
   4 /*-
   5  * Copyright (c) 1990, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * Chris Torek.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <ctype.h>
  37 #include <string.h>
  38
  39 #include "compat.h"
  40
  41 /*
  42  * Find the first occurrence of find in s, ignore case.
  43  */
  44 char *
  45 strcasestr(const char *s, const char *find)
  46 {
  47         char c, sc;
  48         size_t len;
  49
  50         if ((c = *find++) != 0) {
  51                 c = (char)tolower((unsigned char)c);
  52                 len = strlen(find);
  53                 do {
  54                         do {
  55                                 if ((sc = *s++) == 0)
  56                                         return (NULL);
  57                         } while ((char)tolower((unsigned char)sc) != c);
  58                 } while (strncasecmp(s, find, len) != 0);
  59                 s--;
  60         }
  61         return ((char *)s);
  62 }