text: /* Determine the number of screen columns needed for a character.
     Copyright (C) 2006-2007, 2010 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program 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 General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include <wchar.h>
  
  /* Get iswprint.  */
  #include <wctype.h>
  
  #include "localcharset.h"
  #include "streq.h"
  #include "uniwidth.h"
  
  int
  wcwidth (wchar_t wc)
  #undef wcwidth
  {
    /* In UTF-8 locales, use a Unicode aware width function.  */
    const char *encoding = locale_charset ();
    if (STREQ (encoding, "UTF-8", 'U', 'T', 'F', '-', '8', 0, 0, 0 ,0))
      {
        /* We assume that in a UTF-8 locale, a wide character is the same as a
           Unicode character.  */
        return uc_width (wc, encoding);
      }
    else
      {
        /* Otherwise, fall back to the system's wcwidth function.  */
  #if HAVE_WCWIDTH
        return wcwidth (wc);
  #else
        return wc == 0 ? 0 : iswprint (wc) ? 1 : -1;
  #endif
      }
  }
  