/* Copyright (C) 1995-2018 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>

/* Append no more than N wide-character of SRC onto DEST.  */

wchar_t *

__wcsncat_chk (wchar_t *dest, const wchar_t *src, size_t n, size_t destlen)

{

  wchar_t c;

  wchar_t * const s = dest;

  /* Find the end of DEST.  */

  do

    {

      if (__glibc_unlikely (destlen-- == 0))

	__chk_fail ();

      c = *dest++;

    }

  while (c != L'\0');

  /* Make DEST point before next character, so we can increment

     it while memory is read (wins on pipelined cpus).	*/

  ++destlen;

  dest -= 2;

  if (n >= 4)

    {

      size_t n4 = n >> 2;

      do

	{

	  if (__glibc_unlikely (destlen-- == 0))

	    __chk_fail ();

	  c = *src++;

	  *++dest = c;

	  if (c == L'\0')

	    return s;

	  if (__glibc_unlikely (destlen-- == 0))

	    __chk_fail ();

	  c = *src++;

	  *++dest = c;

	  if (c == L'\0')

	    return s;

	  if (__glibc_unlikely (destlen-- == 0))

	    __chk_fail ();

	  c = *src++;

	  *++dest = c;

	  if (c == L'\0')

	    return s;

	  if (__glibc_unlikely (destlen-- == 0))

	    __chk_fail ();

	  c = *src++;

	  *++dest = c;

	  if (c == L'\0')

	    return s;

	} while (--n4 > 0);

      n &= 3;

    }

  while (n > 0)

    {

      if (__glibc_unlikely (destlen-- == 0))

	__chk_fail ();

      c = *src++;

      *++dest = c;

      if (c == L'\0')

	return s;

      n--;

    }

  if (c != L'\0')

    {

      if (__glibc_unlikely (destlen-- == 0))

	__chk_fail ();

      *++dest = L'\0';

    }

  return s;

}