glibc/wcsmbs/wcpncpy.c

88 lines
1.8 KiB
C

/* Copyright (C) 1996-2016 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>
#ifdef WCPNCPY
# define __wcpncpy WCPNCPY
#endif
/* Copy no more than N wide-characters of SRC to DEST, returning the
address of the last character written into DEST. */
wchar_t *
__wcpncpy (wchar_t *dest, const wchar_t *src, size_t n)
{
wint_t c;
wchar_t *const s = 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 -= dest - s;
goto zero_fill;
}
last_chars:
n &= 3;
if (n == 0)
return dest;
for (;;)
{
c = *src++;
--n;
*dest++ = c;
if (c == L'\0')
break;
if (n == 0)
return dest;
}
zero_fill:
while (n-- > 0)
dest[n] = L'\0';
return dest - 1;
}
#ifndef WCPNCPY
weak_alias (__wcpncpy, wcpncpy)
#endif