Blame wcsmbs/wcsncpy.c

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/* Copyright (C) 1995-2018 Free Software Foundation, Inc.
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   This file is part of the GNU C Library.
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   Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library; if not, see
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   <http://www.gnu.org/licenses/>.  */
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#include <wchar.h>
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#ifdef WCSNCPY
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# define __wcsncpy WCSNCPY
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#endif
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/* Copy no more than N wide-characters of SRC to DEST.	*/
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wchar_t *
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__wcsncpy (wchar_t *dest, const wchar_t *src, size_t n)
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{
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  wint_t c;
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  wchar_t *const s = dest;
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  --dest;
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  if (n >= 4)
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    {
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      size_t n4 = n >> 2;
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      for (;;)
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	{
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	  c = *src++;
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	  *++dest = c;
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	  if (c == L'\0')
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	    break;
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	  c = *src++;
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	  *++dest = c;
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	  if (c == L'\0')
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	    break;
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	  c = *src++;
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	  *++dest = c;
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	  if (c == L'\0')
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	    break;
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	  c = *src++;
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	  *++dest = c;
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	  if (c == L'\0')
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	    break;
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	  if (--n4 == 0)
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	    goto last_chars;
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	}
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      n = n - (dest - s) - 1;
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      if (n == 0)
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	return s;
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      goto zero_fill;
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    }
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 last_chars:
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  n &= 3;
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  if (n == 0)
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    return s;
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  do
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    {
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      c = *src++;
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      *++dest = c;
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      if (--n == 0)
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	return s;
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    }
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  while (c != L'\0');
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 zero_fill:
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  do
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    *++dest = L'\0';
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  while (--n > 0);
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  return s;
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}
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#ifndef WCSNCPY
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weak_alias (__wcsncpy, wcsncpy)
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#endif