libjava/classpath/java/text/Bidi.java

   1 /* Bidi.java -- Bidirectional Algorithm implementation
   2    Copyright (C) 2005  Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.text;
  40
  41 /**
  42  * Bidirectional Algorithm implementation.
  43  *
  44  * TODO/FIXME Only one method <code>requiresBidi</code> is implemented
  45  * for now by using <code>Character</code>. The full algorithm is <a
  46  * href="http://www.unicode.org/unicode/reports/tr9/">Unicode Standard
  47  * Annex #9: The Bidirectional Algorithm</a>. A full implementation is
  48  * <a href="http://fribidi.org/">GNU FriBidi</a>.
  49  */
  50 public class Bidi
  51 {
  52   /**
  53    * Returns false if all characters in the text between start and end
  54    * are all left-to-right text. This implementation is just calls
  55    * <code>Character.getDirectionality(char)</code> on all characters
  56    * and makes sure all characters are either explicitly left-to-right
  57    * or neutral in directionality (character types L, EN, ES, ET, AN,
  58    * CS, S and WS).
  59    */
  60   public static boolean requiresBidi(char[] text, int start, int end)
  61   {
  62     for (int i = start; i < end; i++)
  63       {
  64         byte dir = Character.getDirectionality(text[i]);
  65         if (dir != Character.DIRECTIONALITY_LEFT_TO_RIGHT
  66             && dir != Character.DIRECTIONALITY_EUROPEAN_NUMBER
  67             && dir != Character.DIRECTIONALITY_EUROPEAN_NUMBER_SEPARATOR
  68             && dir != Character.DIRECTIONALITY_EUROPEAN_NUMBER_TERMINATOR
  69             && dir != Character.DIRECTIONALITY_ARABIC_NUMBER
  70             && dir != Character.DIRECTIONALITY_COMMON_NUMBER_SEPARATOR
  71             && dir != Character.DIRECTIONALITY_SEGMENT_SEPARATOR
  72             && dir != Character.DIRECTIONALITY_WHITESPACE)
  73           return true;
  74       }
  75
  76     return false;
  77   }
  78 }