glibc/wcsmbs/wcsncpy.c

87 lines
1.8 KiB
C

/* 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>, 1995.
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>
/* Copy no more than N wide-characters of SRC to DEST. */
wchar_t *
wcsncpy (dest, src, n)
wchar_t *dest;
const wchar_t *src;
size_t n;
{
wint_t c;
wchar_t *const s = dest;
--dest;
if (n >= 4)
{
size_t n4 = n >> 2;
for (;;)
{
c = *src++;
*++dest = c;
if (c == L'\0')
break;
c = *src++;
*++dest = c;
if (c == L'\0')
break;
c = *src++;
*++dest = c;
if (c == L'\0')
break;
c = *src++;
*++dest = c;
if (c == L'\0')
break;
if (--n4 == 0)
goto last_chars;
}
n = n - (dest - s) - 1;
if (n == 0)
return s;
goto zero_fill;
}
last_chars:
n &= 3;
if (n == 0)
return s;
do
{
c = *src++;
*++dest = c;
if (--n == 0)
return s;
}
while (c != L'\0');
zero_fill:
do
*++dest = L'\0';
while (--n > 0);
return s;
}