lib/wcwidth.c

   1 /* Determine the number of screen columns needed for a character.
   2    Copyright (C) 2006-2007, 2010-2017 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <wchar.h>
  21
  22 /* Get iswprint.  */
  23 #include <wctype.h>
  24
  25 #include "localcharset.h"
  26 #include "streq.h"
  27 #include "uniwidth.h"
  28
  29 int
  30 wcwidth (wchar_t wc)
  31 #undef wcwidth
  32 {
  33   /* In UTF-8 locales, use a Unicode aware width function.  */
  34   const char *encoding = locale_charset ();
  35   if (STREQ_OPT (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0 ,0))
  36     {
  37       /* We assume that in a UTF-8 locale, a wide character is the same as a
  38          Unicode character.  */
  39       return uc_width (wc, encoding);
  40     }
  41   else
  42     {
  43       /* Otherwise, fall back to the system's wcwidth function.  */
  44 #if HAVE_WCWIDTH
  45       return wcwidth (wc);
  46 #else
  47       return wc == 0 ? 0 : iswprint (wc) ? 1 : -1;
  48 #endif
  49     }
  50 }