newlib-cygwin/newlib/libc/string/wcsncmp.c

92 lines
3.0 KiB
C

/*
FUNCTION
<<wcsncmp>>---compare part of two wide-character strings
ANSI_SYNOPSIS
#include <wchar.h>
int wcsncmp(const wchar_t *<[s1]>, const wchar_t *<[s2]>, size_t <[n]>);
TRAD_SYNOPSIS
int wcsncmp(<[s1]>, <[s2]>, <[n]>
const wchar_t *<[s1]>;
const wchar_t *<[s2]>;
size_t <[n]>;
DESCRIPTION
The <<wcsncmp>> function compares not more than <[n]> wide-character
codes (wide-character codes that follow a null wide-character code are
not compared) from the array pointed to by <[s1]> to the array pointed
to by <[s2]>.
The sign of a non-zero return value is determined by the sign of the
difference between the values of the first pair of wide-character codes
that differ in the objects being compared.
RETURNS
Upon successful completion, <<wcsncmp>> returns an integer greater than,
equal to or less than 0, if the possibly null-terminated array pointed
to by <[s1]> is greater than, equal to or less than the possibly
null-terminated array pointed to by <[s2]> respectively.
PORTABILITY
<<wcsncmp>> is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.
*/
/* $NetBSD$ */
/*
* Copyright (c) 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <_ansi.h>
#include <wchar.h>
int
_DEFUN (wcsncmp, (s1, s2, n),
_CONST wchar_t * s1 _AND
_CONST wchar_t * s2 _AND
size_t n)
{
if (n == 0)
return (0);
do
{
if (*s1 != *s2++)
{
return (*s1 - *--s2);
}
if (*s1++ == 0)
break;
}
while (--n != 0);
return (0);
}