wcsmbs/wcwidth.h

   1 /* Internal header containing implementation of wcwidth() function.
   2    Copyright (C) 1996-2023 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <wchar.h>
  20 #include <wctype.h>
  21 #include "../wctype/wchar-lookup.h"
  22 #include "../locale/localeinfo.h"
  23
  24 /* Table containing width information.  */
  25 extern const char *__ctype32_width attribute_hidden;
  26
  27 static __inline int
  28 internal_wcwidth (wchar_t wc)
  29 {
  30   unsigned char res;
  31
  32   /* The tables have been prepared in such a way that
  33      1. wc == L'\0' yields res = 0,
  34      2. !iswprint (wc) implies res = '\xff'.  */
  35   res = wcwidth_table_lookup (_NL_CURRENT (LC_CTYPE, _NL_CTYPE_WIDTH), wc);
  36
  37   return res == (unsigned char) '\xff' ? -1 : (int) res;
  38 }