contrib/file/src/strcasestr.c

   1 /*      $NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $  */
   2
   3 /*-
   4  * Copyright (c) 1990, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Chris Torek.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #if defined(LIBC_SCCS) && !defined(lint)
  36 __RCSID("$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $");
  37 __RCSID("$NetBSD: strncasecmp.c,v 1.2 2007/06/04 18:19:27 christos Exp $");
  38 #endif /* LIBC_SCCS and not lint */
  39
  40 #include "file.h"
  41
  42 #include <assert.h>
  43 #include <ctype.h>
  44 #include <string.h>
  45
  46 static int
  47 _strncasecmp(const char *s1, const char *s2, size_t n)
  48 {
  49         if (n != 0) {
  50                 const unsigned char *us1 = (const unsigned char *)s1,
  51                                 *us2 = (const unsigned char *)s2;
  52
  53                 do {
  54                         if (tolower(*us1) != tolower(*us2++))
  55                                 return tolower(*us1) - tolower(*--us2);
  56                         if (*us1++ == '\0')
  57                                 break;
  58                 } while (--n != 0);
  59         }
  60         return 0;
  61 }
  62
  63 /*
  64  * Find the first occurrence of find in s, ignore case.
  65  */
  66 char *
  67 strcasestr(const char *s, const char *find)
  68 {
  69         char c, sc;
  70         size_t len;
  71
  72         if ((c = *find++) != 0) {
  73                 c = tolower((unsigned char)c);
  74                 len = strlen(find);
  75                 do {
  76                         do {
  77                                 if ((sc = *s++) == 0)
  78                                         return (NULL);
  79                         } while ((char)tolower((unsigned char)sc) != c);
  80                 } while (_strncasecmp(s, find, len) != 0);
  81                 s--;
  82         }
  83         return (char *)(intptr_t)(s);
  84 }