glibc/wcsmbs/wcsncmp.c

71 lines
1.9 KiB
C

/* Copyright (C) 1995-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <wchar.h>
#ifndef WCSNCMP
# define WCSNCMP wcsncmp
#endif
/* Compare no more than N characters of S1 and S2,
returning less than, equal to or greater than zero
if S1 is lexicographically less than, equal to or
greater than S2. */
int
WCSNCMP (const wchar_t *s1, const wchar_t *s2, size_t n)
{
wchar_t c1 = L'\0';
wchar_t c2 = L'\0';
if (n >= 4)
{
size_t n4 = n >> 2;
do
{
c1 = *s1++;
c2 = *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 > c2 ? 1 : (c1 < c2 ? -1 : 0);
c1 = *s1++;
c2 = *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 > c2 ? 1 : (c1 < c2 ? -1 : 0);
c1 = *s1++;
c2 = *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 > c2 ? 1 : (c1 < c2 ? -1 : 0);
c1 = *s1++;
c2 = *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 > c2 ? 1 : (c1 < c2 ? -1 : 0);
} while (--n4 > 0);
n &= 3;
}
while (n > 0)
{
c1 = *s1++;
c2 = *s2++;
if (c1 == L'\0' || c1 != c2)
return c1 > c2 ? 1 : (c1 < c2 ? -1 : 0);
n--;
}
return 0;
}