libjava/java/text/ChoiceFormat.java

   1 // ChoiceFormat.java - Formatter for `switch'-like string substitution.
   2
   3 /* Copyright (C) 1999  Free Software Foundation
   4
   5    This file is part of libgcj.
   6
   7 This software is copyrighted work licensed under the terms of the
   8 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   9 details.  */
  10
  11 package java.text;
  12
  13 import java.util.Vector;
  14
  15 /**
  16  * @author Tom Tromey <tromey@cygnus.com>
  17  * @date March 9, 1999
  18  */
  19 /* Written using "Java Class Libraries", 2nd edition, plus online
  20  * API docs for JDK 1.2 from http://www.javasoft.com.
  21  * Status:  Believed complete and correct to 1.1.
  22  */
  23
  24 public class ChoiceFormat extends NumberFormat
  25 {
  26   // Note: we assume the same kind of quoting rules apply here.
  27   // This isn't explicitly documented.  But for instance we accept
  28   // '#' as a literal hash in a format string.
  29   public void applyPattern (String newPattern)
  30     {
  31       int index = 0, max = newPattern.length();
  32       Vector stringVec = new Vector ();
  33       Vector limitVec = new Vector ();
  34       StringBuffer buf = new StringBuffer ();
  35
  36       while (true)
  37         {
  38           // Find end of double.
  39           int dstart = index;
  40           while (index < max)
  41             {
  42               char c = newPattern.charAt(index);
  43               if (c == '#' || c == '\u2064' || c == '<')
  44                 break;
  45               ++index;
  46             }
  47
  48           if (index == max)
  49             throw new IllegalArgumentException ("unexpected end of text");
  50           Double d = new Double (newPattern.substring(dstart, index));
  51
  52           if (newPattern.charAt(index) == '<')
  53             d = new Double (nextDouble (d.doubleValue()));
  54
  55           limitVec.addElement(d);
  56
  57           // Scan text.
  58           ++index;
  59           buf.setLength(0);
  60           while (index < max)
  61             {
  62               char c = newPattern.charAt(index);
  63               if (c == '\'' && index < max + 1
  64                   && newPattern.charAt(index + 1) == '\'')
  65                 {
  66                   buf.append(c);
  67                   ++index;
  68                 }
  69               else if (c == '\'' && index < max + 2)
  70                 {
  71                   buf.append(newPattern.charAt(index + 1));
  72                   index += 2;
  73                 }
  74               else if (c == '|')
  75                 break;
  76               else
  77                 buf.append(c);
  78               ++index;
  79             }
  80
  81           stringVec.addElement(buf.toString());
  82           if (index == max)
  83             break;
  84           ++index;
  85         }
  86
  87       strings = new String[stringVec.size()];
  88       stringVec.copyInto(strings);
  89
  90       limits = new double[limitVec.size()];
  91       for (int i = 0; i < limits.length; ++i)
  92         {
  93           Double d = (Double) limitVec.elementAt(i);
  94           limits[i] = d.doubleValue();
  95         }
  96     }
  97
  98   public ChoiceFormat (String newPattern)
  99     {
 100       super ();
 101       applyPattern (newPattern);
 102     }
 103
 104   public ChoiceFormat (double[] limits, String[] strings)
 105     {
 106       super ();
 107       setChoices (limits, strings);
 108     }
 109
 110   public Object clone ()
 111     {
 112       return new ChoiceFormat (limits, strings);
 113     }
 114
 115   public boolean equals (Object obj)
 116     {
 117       if (! (obj instanceof ChoiceFormat))
 118         return false;
 119       ChoiceFormat cf = (ChoiceFormat) obj;
 120       if (limits.length != cf.limits.length)
 121         return false;
 122       for (int i = limits.length - 1; i >= 0; --i)
 123         {
 124           if (limits[i] != cf.limits[i]
 125               || !strings[i].equals(cf.strings[i]))
 126             return false;
 127         }
 128       return true;
 129     }
 130
 131   public StringBuffer format (long num, StringBuffer appendBuf,
 132                               FieldPosition pos)
 133     {
 134       return format ((double) num, appendBuf, pos);
 135     }
 136
 137   public StringBuffer format (double num, StringBuffer appendBuf,
 138                               FieldPosition pos)
 139     {
 140       if (limits.length == 0)
 141         return appendBuf;
 142
 143       int index =  0;
 144       if (! Double.isNaN(num) && num >= limits[0])
 145         {
 146           for (; index < limits.length - 1; ++index)
 147             {
 148               if (limits[index] <= num
 149                   && index != limits.length - 2
 150                   && num < limits[index + 1])
 151                 break;
 152             }
 153         }
 154
 155       return appendBuf.append(strings[index]);
 156     }
 157
 158   public Object[] getFormats ()
 159     {
 160       return (Object[]) strings.clone();
 161     }
 162
 163   public double[] getLimits ()
 164     {
 165       return (double[]) limits.clone();
 166     }
 167
 168   public int hashCode ()
 169     {
 170       int hash = 0;
 171       for (int i = 0; i < limits.length; ++i)
 172         {
 173           long v = Double.doubleToLongBits(limits[i]);
 174           hash ^= (v ^ (v >>> 32));
 175           hash ^= strings[i].hashCode();
 176         }
 177       return hash;
 178     }
 179
 180   public static final double nextDouble (double d)
 181     {
 182       return nextDouble (d, true);
 183     }
 184
 185   public static double nextDouble (double d, boolean next)
 186     {
 187       if (Double.isInfinite(d) || Double.isNaN(d))
 188         return d;
 189
 190       long bits = Double.doubleToLongBits(d);
 191
 192       long mantMask = (1L << mantissaBits) - 1;
 193       long mantissa = bits & mantMask;
 194
 195       long expMask = (1L << exponentBits) - 1;
 196       long exponent = (bits >>> mantissaBits) & expMask;
 197
 198       if (next ^ (bits < 0)) // Increment magnitude
 199         {
 200           if (mantissa == (1L << mantissaBits) - 1)
 201             {
 202               mantissa = 0L;
 203               exponent++;
 204
 205               // Check for absolute overflow.
 206               if (exponent >= (1L << mantissaBits))
 207                 return (bits > 0) ? Double.POSITIVE_INFINITY
 208                   : Double.NEGATIVE_INFINITY;
 209             }
 210           else
 211             mantissa++;
 212         }
 213       else // Decrement magnitude
 214         {
 215           if (exponent == 0L && mantissa == 0L)
 216             {
 217               // The only case where there is a change of sign
 218               return next ? Double.MIN_VALUE : -Double.MIN_VALUE;
 219             }
 220           else
 221             {
 222               if (mantissa == 0L)
 223                 {
 224                   mantissa = (1L << mantissaBits) - 1;
 225                   exponent--;
 226                 }
 227               else
 228                 mantissa--;
 229             }
 230         }
 231
 232       long result = bits < 0 ? 1 : 0;
 233       result = (result << exponentBits) | exponent;
 234       result = (result << mantissaBits) | mantissa;
 235       return Double.longBitsToDouble(result);
 236     }
 237
 238   public Number parse (String sourceStr, ParsePosition pos)
 239     {
 240       int index = pos.getIndex();
 241       for (int i = 0; i < limits.length; ++i)
 242         {
 243           if (sourceStr.startsWith(strings[i], index))
 244             {
 245               pos.setIndex(index + strings[i].length());
 246               return new Double (limits[i]);
 247             }
 248         }
 249       pos.setErrorIndex(index);
 250       return new Double (Double.NaN);
 251     }
 252
 253   public static final double previousDouble (double d)
 254     {
 255       return nextDouble (d, false);
 256     }
 257
 258   public void setChoices (double[] limits, String[] strings)
 259     {
 260       if (limits == null || strings == null)
 261         throw new NullPointerException ();
 262       if (limits.length != strings.length)
 263         throw new IllegalArgumentException ();
 264       this.strings = (String[]) strings.clone();
 265       this.limits = (double[]) limits.clone();
 266     }
 267
 268   private final void quoteString (StringBuffer dest, String text)
 269     {
 270       int max = text.length();
 271       for (int i = 0; i < max; ++i)
 272         {
 273           char c = text.charAt(i);
 274           if (c == '\'')
 275             {
 276               dest.append(c);
 277               dest.append(c);
 278             }
 279           else if (c == '#' || c == '|' || c == '\u2064' || c == '<')
 280             {
 281               dest.append('\'');
 282               dest.append(c);
 283               dest.append('\'');
 284             }
 285           else
 286             dest.append(c);
 287         }
 288     }
 289
 290   public String toPattern ()
 291     {
 292       StringBuffer result = new StringBuffer ();
 293       for (int i = 0; i < limits.length; ++i)
 294         {
 295           result.append(limits[i]);
 296           result.append('#');
 297           quoteString (result, strings[i]);
 298         }
 299       return result.toString();
 300     }
 301
 302   // Formats and limits.
 303   private String[] strings;
 304   private double[] limits;
 305
 306   // Number of mantissa bits in double.
 307   private static final int mantissaBits = 52;
 308   // Number of exponent bits in a double.
 309   private static final int exponentBits = 11;
 310 }