toolchain/gcc/newlib/libc/string/wcsstr.c

   1 /*
   2 FUNCTION
   3         <<wcsstr>>---find a wide-character substring
   4
   5 ANSI_SYNOPSIS
   6         #include <wchar.h>
   7         wchar_t *wcsstr(const wchar_t *<[big]>, const wchar_t *<[little]>);
   8
   9 TRAD_SYNOPSIS
  10         wchar_t *wcsstr(<[big]>, <[little]>
  11         const wchar_t *<[big]>;
  12         const wchar_t *<[little]>;
  13
  14 DESCRIPTION
  15         The <<wcsstr>> function locates the first occurrence in the
  16         wide-character string pointed to by <[big]> of the sequence of
  17         wide-characters (excluding the terminating null wide-character) in the
  18         wide-character string pointed to by <[little]>.
  19
  20 RETURNS
  21         On successful completion, <<wcsstr>> returns a pointer to the located
  22         wide-character string, or a null pointer if the wide-character string
  23         is not found.
  24
  25         If <[little]> points to a wide-character string with zero length,
  26         the function returns <[big]>.
  27
  28 PORTABILITY
  29 <<wcsstr>> is ISO/IEC 9899/AMD1:1995 (ISO C).
  30
  31 */
  32
  33 /*      $NetBSD: wcsstr.c,v 1.1 2000/12/23 23:14:37 itojun Exp $        */
  34
  35 /*-
  36  * Copyright (c)1999 Citrus Project,
  37  * All rights reserved.
  38  *
  39  * Redistribution and use in source and binary forms, with or without
  40  * modification, are permitted provided that the following conditions
  41  * are met:
  42  * 1. Redistributions of source code must retain the above copyright
  43  *    notice, this list of conditions and the following disclaimer.
  44  * 2. Redistributions in binary form must reproduce the above copyright
  45  *    notice, this list of conditions and the following disclaimer in the
  46  *    documentation and/or other materials provided with the distribution.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  *
  60  *      citrus Id: wcsstr.c,v 1.2 2000/12/21 05:07:25 itojun Exp
  61  */
  62
  63 #include <_ansi.h>
  64 #include <stddef.h>
  65 #include <wchar.h>
  66
  67 wchar_t *
  68 _DEFUN (wcsstr, (big, little),
  69         _CONST wchar_t * big _AND
  70         _CONST wchar_t * little)
  71 {
  72   _CONST wchar_t *p;
  73   _CONST wchar_t *q;
  74   _CONST wchar_t *r;
  75
  76   if (!*little)
  77     {
  78       /* LINTED interface specification */
  79       return (wchar_t *) big;
  80     }
  81   if (wcslen (big) < wcslen (little))
  82     return NULL;
  83
  84   p = big;
  85   q = little;
  86   while (*p)
  87     {
  88       q = little;
  89       r = p;
  90       while (*q)
  91         {
  92           if (*r != *q)
  93             break;
  94           q++;
  95           r++;
  96         }
  97       if (!*q)
  98         {
  99           /* LINTED interface specification */
 100           return (wchar_t *) p;
 101         }
 102       p++;
 103     }
 104   return NULL;
 105 }