lib/libc/string/wcsstr.c

   1 /*      $NetBSD: wcsstr.c,v 1.4 2005/11/29 03:12:00 christos Exp $      */
   2
   3 /*-
   4  * Copyright (c)1999 Citrus Project,
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  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  *      citrus Id: wcsstr.c,v 1.2 2000/12/21 05:07:25 itojun Exp
  29  */
  30
  31 #include <sys/cdefs.h>
  32 #if defined(LIBC_SCCS) && !defined(lint)
  33 __RCSID("$NetBSD: wcsstr.c,v 1.4 2005/11/29 03:12:00 christos Exp $");
  34 #endif /* LIBC_SCCS and not lint */
  35
  36 #include <assert.h>
  37 #include <wchar.h>
  38
  39 wchar_t *
  40 #ifdef WCSWCS
  41 wcswcs(big, little)
  42 #else
  43 wcsstr(big, little)
  44 #endif
  45         const wchar_t *big;
  46         const wchar_t *little;
  47 {
  48         const wchar_t *p;
  49         const wchar_t *q;
  50         const wchar_t *r;
  51
  52         _DIAGASSERT(big != NULL);
  53         _DIAGASSERT(little != NULL);
  54
  55         if (!*little)
  56                 return __UNCONST(big);
  57         if (wcslen(big) < wcslen(little))
  58                 return NULL;
  59
  60         p = big;
  61         q = little;
  62         while (*p) {
  63                 q = little;
  64                 r = p;
  65                 while (*q) {
  66                         if (*r != *q)
  67                                 break;
  68                         q++;
  69                         r++;
  70                 }
  71                 if (!*q)
  72                         return __UNCONST(p);
  73                 p++;
  74         }
  75         return NULL;
  76 }