libjava/classpath/gnu/CORBA/BigDecimalHelper.java

   1 /* BigDecimalHelper.java --
   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 gnu.CORBA;
  40
  41 import gnu.java.lang.CPStringBuilder;
  42
  43 import java.io.ByteArrayInputStream;
  44 import java.io.ByteArrayOutputStream;
  45 import java.io.IOException;
  46
  47 import java.math.BigDecimal;
  48 import java.math.BigInteger;
  49
  50 import org.omg.CORBA.TypeCodePackage.BadKind;
  51
  52 /**
  53  * Reads and writes BigDecimal as CORBA <code>fixed</code>.
  54  * The format, described in CORBA specification, requires to store
  55  * data in hexadecimal format, two digits per byte (oceted), most
  56  * significant digit first. The last half-byte in the representation
  57  * stores the sign, being 0xD for negative numbers and 0xC for
  58  * zero and positive numbers. To have the even number of half bytes,
  59  * 0x0 is appended to the beginning, if required. The position of the
  60  * decimal point is not stored.
  61  *
  62  * @author Audrius Meskauskas (AudriusA@Bioinformatics.org)
  63  */
  64 public class BigDecimalHelper
  65 {
  66   {
  67   }
  68
  69   /**
  70    * @todo remove from the release version.
  71    */
  72   public static void main(String[] args)
  73   {
  74     try
  75       {
  76         ByteArrayOutputStream b = new ByteArrayOutputStream();
  77         BigDecimal d = new BigDecimal("12234.54689");
  78
  79         write(b, d);
  80
  81         byte[] a = b.toByteArray();
  82
  83         for (int i = 0; i < a.length; i++)
  84           {
  85             int k = a [ i ] & 0xFF;
  86             System.out.print(Integer.toHexString(k) + " ");
  87           }
  88
  89         System.out.println("Now reading");
  90
  91         ByteArrayInputStream bin = new ByteArrayInputStream(a);
  92
  93         BigDecimal r = read(bin, d.scale());
  94
  95         System.out.println(r);
  96       }
  97     catch (Exception ex)
  98       {
  99         ex.printStackTrace();
 100       }
 101   }
 102
 103   /**
 104    * Read the CORBA fixed, autodetecting the number of bytes
 105    * and assuming the given scale.
 106    */
 107   public static BigDecimal read(java.io.InputStream in, int scale)
 108                          throws IOException
 109   {
 110     ByteArrayOutputStream bout = new ByteArrayOutputStream();
 111
 112     int f;
 113
 114     do
 115       {
 116         f = in.read();
 117         if (f >= 0)
 118           bout.write(f);
 119       }
 120     // The last byte has 0xC or 0xD in the last halfbyte.
 121     while ((f & 0xF) <= 0x9);
 122
 123     return createFixed(scale, bout.toByteArray());
 124   }
 125
 126   /**
 127    * Write the big decimal as CORBA <code>fixed<.code>.
 128    * The scale will not be stored.
 129    *
 130    * @param out a stream to write into.
 131    * @param x a big decimal to write.
 132    *
 133    * @throws IOException if the stream write method throws one.
 134    * @throws BadKind if this BigDecimal has more digits than
 135    * specified.
 136    */
 137   public static void write(java.io.OutputStream out, BigDecimal x)
 138                     throws IOException, BadKind
 139   {
 140     CPStringBuilder v = new CPStringBuilder(x.unscaledValue().toString());
 141
 142     boolean negative = v.charAt(0) == '-';
 143
 144     if (negative)
 145       v = v.deleteCharAt(0);
 146
 147     if ( (v.length() & 1) == 0)
 148       v.insert(0, '0');
 149
 150     int c;
 151
 152     for (int i = 0; i < v.length() - 1; i = i + 2)
 153       {
 154         c = ((v.charAt(i) - '0') << 4) | (v.charAt(i + 1) - '0');
 155         out.write(c);
 156       }
 157
 158     c = ((v.charAt(v.length() - 1) - '0') << 4) | (negative ? 0xD : 0xC);
 159
 160     out.write(c);
 161   }
 162
 163   /**
 164    * Convert the loaded byte array, representing
 165    * CORBA <code>fixed</code>, into an instance of
 166    * the {@link BigDecimal}
 167    */
 168   private static BigDecimal createFixed(int scale, byte[] d)
 169   {
 170     CPStringBuilder s = new CPStringBuilder(2 * d.length);
 171
 172     int last = d.length - 1;
 173
 174     if ((d [ last ] & 0xF) == 0xD)
 175       s.append('-');
 176
 177     if (last > 0)
 178       for (int i = 0; i < last; i++)
 179         {
 180           s.append((char) (((d [ i ] >> 4) & 0xF) + '0'));
 181           s.append((char) (((d [ i ]) & 0xF) + '0'));
 182         }
 183
 184     s.append((char) (((d [ last ] >> 4) & 0xF) + '0'));
 185
 186     BigInteger b = new BigInteger(s.toString());
 187     BigDecimal dec = new BigDecimal(b, scale);
 188
 189     return dec;
 190   }
 191 }