wcsmbs/wcwidth.h

   1 /* Internal header containing implementation of wcwidth() function.
   2    Copyright (C) 1996-2018 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1996.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <wchar.h>
  21 #include <wctype.h>
  22 #include "../wctype/wchar-lookup.h"
  23 #include "../locale/localeinfo.h"
  24
  25 /* Table containing width information.  */
  26 extern const char *__ctype32_width attribute_hidden;
  27
  28 static __inline int
  29 internal_wcwidth (wchar_t wc)
  30 {
  31   unsigned char res;
  32
  33   /* The tables have been prepared in such a way that
  34      1. wc == L'\0' yields res = 0,
  35      2. !iswprint (wc) implies res = '\xff'.  */
  36   res = wcwidth_table_lookup (_NL_CURRENT (LC_CTYPE, _NL_CTYPE_WIDTH), wc);
  37
  38   return res == (unsigned char) '\xff' ? -1 : (int) res;
  39 }