glibc/wcsmbs/wcsncmp.c

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/* Copyright (C) 1995, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <wchar.h>
/* Compare no more than N characters of S1 and S2,
returning less than, equal to or greater than zero
if S1 is lexiographically less than, equal to or
greater than S2. */
int
wcsncmp (s1, s2, n)
const wchar_t *s1;
const wchar_t *s2;
size_t n;
{
uwchar_t c1 = L'\0';
uwchar_t c2 = L'\0';
if (n >= 4)
{
size_t n4 = n >> 2;
do
{
c1 = (uwchar_t) *s1++;
c2 = (uwchar_t) *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 - c2;
c1 = (uwchar_t) *s1++;
c2 = (uwchar_t) *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 - c2;
c1 = (uwchar_t) *s1++;
c2 = (uwchar_t) *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 - c2;
c1 = (uwchar_t) *s1++;
c2 = (uwchar_t) *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 - c2;
} while (--n4 > 0);
n &= 3;
}
while (n > 0)
{
c1 = (uwchar_t) *s1++;
c2 = (uwchar_t) *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 - c2;
n--;
}
return c1 - c2;
}