newlib/libc/string/wcscmp.c

   1 /*
   2 FUNCTION
   3         <<wcscmp>>---compare two wide-character strings
   4
   5 SYNOPSIS
   6         #include <wchar.h>
   7         int wcscmp(const wchar_t *<[s1]>, *<[s2]>);
   8
   9 DESCRIPTION
  10         The <<wcscmp>> function compares the wide-character string pointed to
  11         by <[s1]> to the wide-character string pointed to by <[s2]>.
  12
  13         The sign of a non-zero return value is determined by the sign of the
  14         difference between the values of the first pair of wide-character codes
  15         that differ in the objects being compared.
  16
  17 RETURNS
  18         Upon completion, <<wcscmp>> returns an integer greater than, equal to
  19         or less than 0, if the wide-character string pointed to by <[s1]> is
  20         greater than, equal to or less than the wide-character string pointed
  21         to by <[s2]> respectively.
  22
  23 PORTABILITY
  24 <<wcscmp>> is ISO/IEC 9899/AMD1:1995 (ISO C).
  25
  26 No supporting OS subroutines are required.
  27 */
  28
  29 /*      $NetBSD$        */
  30
  31 /*-
  32  * Copyright (c) 1990, 1993
  33  *      The Regents of the University of California.  All rights reserved.
  34  *
  35  * This code is derived from software contributed to Berkeley by
  36  * Chris Torek.
  37  *
  38  * Redistribution and use in source and binary forms, with or without
  39  * modification, are permitted provided that the following conditions
  40  * are met:
  41  * 1. Redistributions of source code must retain the above copyright
  42  *    notice, this list of conditions and the following disclaimer.
  43  * 2. Redistributions in binary form must reproduce the above copyright
  44  *    notice, this list of conditions and the following disclaimer in the
  45  *    documentation and/or other materials provided with the distribution.
  46  * 3. Neither the name of the University nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  60  * SUCH DAMAGE.
  61  */
  62
  63 #include <_ansi.h>
  64 #include <wchar.h>
  65
  66 /*
  67  * Compare strings.
  68  */
  69 int
  70 wcscmp (const wchar_t * s1,
  71         const wchar_t * s2)
  72 {
  73
  74   while (*s1 == *s2++)
  75     if (*s1++ == 0)
  76       return (0);
  77   return (*s1 - *--s2);
  78 }