newlib/libc/string/wcsrchr.c

   1 /*
   2 FUNCTION
   3         <<wcsrchr>>---wide-character string scanning operation
   4
   5 SYNOPSIS
   6         #include <wchar.h>
   7         wchar_t *wcsrchr(const wchar_t *<[s]>, wchar_t <[c]>);
   8
   9 DESCRIPTION
  10         The <<wcsrchr>> function locates the last occurrence of <[c]> in the
  11         wide-character string pointed to by <[s]>. The value of <[c]> must be a
  12         character representable as a type wchar_t and must be a wide-character
  13         code corresponding to a valid character in the current locale.
  14         The terminating null wide-character code is considered to be part of
  15         the wide-character string.
  16
  17 RETURNS
  18         Upon successful completion, <<wcsrchr>> returns a pointer to the
  19         wide-character code or a null pointer if <[c]> does not occur in the
  20         wide-character string.
  21
  22 PORTABILITY
  23 <<wcsrchr>> is ISO/IEC 9899/AMD1:1995 (ISO C).
  24
  25 No supporting OS subroutines are required.
  26 */
  27
  28 /*      $NetBSD: wcsrchr.c,v 1.1 2000/12/23 23:14:37 itojun Exp $       */
  29
  30 /*-
  31  * Copyright (c)1999 Citrus Project,
  32  * All rights reserved.
  33  *
  34  * Redistribution and use in source and binary forms, with or without
  35  * modification, are permitted provided that the following conditions
  36  * are met:
  37  * 1. Redistributions of source code must retain the above copyright
  38  *    notice, this list of conditions and the following disclaimer.
  39  * 2. Redistributions in binary form must reproduce the above copyright
  40  *    notice, this list of conditions and the following disclaimer in the
  41  *    documentation and/or other materials provided with the distribution.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  53  * SUCH DAMAGE.
  54  *
  55  *      citrus Id: wcsrchr.c,v 1.2 2000/12/21 05:07:25 itojun Exp
  56  */
  57
  58 #include <_ansi.h>
  59 #include <stddef.h>
  60 #include <wchar.h>
  61
  62 wchar_t *
  63 wcsrchr (const wchar_t * s,
  64         wchar_t c)
  65 {
  66   const wchar_t *p;
  67
  68   p = s;
  69   while (*p)
  70     p++;
  71   while (s <= p)
  72     {
  73       if (*p == c)
  74         {
  75           /* LINTED interface specification */
  76           return (wchar_t *) p;
  77         }
  78       p--;
  79     }
  80   return NULL;
  81 }