newlib/libc/string/wmemcmp.c

   1 /*
   2 FUNCTION
   3         <<wmemcmp>>---compare wide characters in memory
   4
   5 SYNOPSIS
   6         #include <wchar.h>
   7         int wmemcmp(const wchar_t *<[s1]>, const wchar_t *<[s2]>, size_t <[n]>);
   8
   9 DESCRIPTION
  10         The <<wmemcmp>> function compares the first <[n]> wide characters of the
  11         object pointed to by <[s1]> to the first <[n]> wide characters of the
  12         object pointed to by <[s2]>. This function is not affected by locale
  13         and all wchar_t values are treated identically. The null wide character
  14         and wchar_t values not corresponding to valid characters are not treated
  15         specially.
  16
  17         If <[n]> is zero, <[s1]> and <[s2]> must be a valid pointers and the
  18         function behaves as if the two objects compare equal.
  19
  20 RETURNS
  21         The <<wmemcmp>> function returns an integer greater than, equal to,
  22         or less than zero, accordingly as the object pointed to by <[s1]> is
  23         greater than, equal to, or less than the object pointed to by <[s2]>.
  24
  25 PORTABILITY
  26 <<wmemcmp>> is ISO/IEC 9899/AMD1:1995 (ISO C).
  27
  28 No supporting OS subroutines are required.
  29 */
  30
  31 /*      $NetBSD: wmemcmp.c,v 1.1 2000/12/23 23:14:37 itojun Exp $       */
  32
  33 /*-
  34  * Copyright (c)1999 Citrus Project,
  35  * All rights reserved.
  36  *
  37  * Redistribution and use in source and binary forms, with or without
  38  * modification, are permitted provided that the following conditions
  39  * are met:
  40  * 1. Redistributions of source code must retain the above copyright
  41  *    notice, this list of conditions and the following disclaimer.
  42  * 2. Redistributions in binary form must reproduce the above copyright
  43  *    notice, this list of conditions and the following disclaimer in the
  44  *    documentation and/or other materials provided with the distribution.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  *
  58  *      citrus Id: wmemcmp.c,v 1.2 2000/12/20 14:08:31 itojun Exp
  59  */
  60
  61 #include <_ansi.h>
  62 #include <wchar.h>
  63
  64 int
  65 wmemcmp (const wchar_t * s1,
  66         const wchar_t * s2,
  67         size_t n)
  68 {
  69   size_t i;
  70
  71   for (i = 0; i < n; i++)
  72     {
  73       if (*s1 != *s2)
  74         {
  75           /* wchar might be unsigned */
  76           return *s1 > *s2 ? 1 : -1;
  77         }
  78       s1++;
  79       s2++;
  80     }
  81   return 0;
  82 }