libjava/gnu/java/net/BASE64.java

   1 /* BASE.java --
   2    Copyright (C) 2003, 2004 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., 59 Temple Place, Suite 330, Boston, MA
  19 02111-1307 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.java.net;
  40
  41 /**
  42  * Encodes and decodes text according to the BASE64 encoding.
  43  *
  44  * @author Chris Burdess (dog@gnu.org)
  45  */
  46 public final class BASE64
  47 {
  48   private static final byte[] src = {
  49     0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a,
  50     0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54,
  51     0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x61, 0x62, 0x63, 0x64,
  52     0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e,
  53     0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
  54     0x79, 0x7a, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
  55     0x38, 0x39, 0x2b, 0x2f
  56   };
  57
  58   private static final byte[] dst;
  59   static
  60   {
  61     dst = new byte[0x100];
  62     for (int i = 0x0; i < 0xff; i++)
  63       {
  64         dst[i] = -1;
  65       }
  66     for (int i = 0; i < src.length; i++)
  67       {
  68         dst[src[i]] = (byte) i;
  69       }
  70   }
  71
  72   private BASE64()
  73   {
  74   }
  75
  76   /**
  77    * Encode the specified byte array using the BASE64 algorithm.
  78    *
  79    * @param bs the source byte array
  80    */
  81   public static byte[] encode(byte[] bs)
  82   {
  83     int si = 0, ti = 0;         // source/target array indices
  84     byte[] bt = new byte[((bs.length + 2) * 4) / 3];     // target byte array
  85     for (; si < bs.length; si += 3)
  86       {
  87         int buflen = bs.length - si;
  88         if (buflen == 1)
  89           {
  90             byte b = bs[si];
  91             int i = 0;
  92             bt[ti++] = src[b >>> 2 & 0x3f];
  93             bt[ti++] = src[(b << 4 & 0x30) + (i >>> 4 & 0xf)];
  94           }
  95         else if (buflen == 2)
  96           {
  97             byte b1 = bs[si], b2 = bs[si + 1];
  98             int i = 0;
  99             bt[ti++] = src[b1 >>> 2 & 0x3f];
 100             bt[ti++] = src[(b1 << 4 & 0x30) + (b2 >>> 4 & 0xf)];
 101             bt[ti++] = src[(b2 << 2 & 0x3c) + (i >>> 6 & 0x3)];
 102           }
 103         else
 104           {
 105             byte b1 = bs[si], b2 = bs[si + 1], b3 = bs[si + 2];
 106             bt[ti++] = src[b1 >>> 2 & 0x3f];
 107             bt[ti++] = src[(b1 << 4 & 0x30) + (b2 >>> 4 & 0xf)];
 108             bt[ti++] = src[(b2 << 2 & 0x3c) + (b3 >>> 6 & 0x3)];
 109             bt[ti++] = src[b3 & 0x3f];
 110           }
 111       }
 112     /*while (ti < bt.length)
 113       {
 114         bt[ti++] = 0x3d;
 115       }*/
 116     return bt;
 117   }
 118
 119   /**
 120    * Decode the specified byte array using the BASE64 algorithm.
 121    *
 122    * @param bs the source byte array
 123    */
 124   public static byte[] decode(byte[] bs)
 125   {
 126     int srclen = bs.length;
 127     while (srclen > 0 && bs[srclen - 1] == 0x3d)
 128       {
 129         srclen--; /* strip padding character */
 130       }
 131     byte[] buffer = new byte[srclen];
 132     int buflen = 0;
 133     int si = 0;
 134     int len = srclen - si;
 135     while (len > 0)
 136       {
 137         byte b0 = dst[bs[si++] & 0xff];
 138         byte b2 = dst[bs[si++] & 0xff];
 139         buffer[buflen++] = (byte) (b0 << 2 & 0xfc | b2 >>> 4 & 0x3);
 140         if (len > 2)
 141           {
 142             b0 = b2;
 143             b2 = dst[bs[si++] & 0xff];
 144             buffer[buflen++] = (byte) (b0 << 4 & 0xf0 | b2 >>> 2 & 0xf);
 145             if (len > 3)
 146               {
 147                 b0 = b2;
 148                 b2 = dst[bs[si++] & 0xff];
 149                 buffer[buflen++] = (byte) (b0 << 6 & 0xc0 | b2 & 0x3f);
 150               }
 151           }
 152         len = srclen - si;
 153       }
 154     byte[] bt = new byte[buflen];
 155     System.arraycopy(buffer, 0, bt, 0, buflen);
 156     return bt;
 157   }
 158
 159   public static void main(String[] args)
 160   {
 161     boolean decode = false;
 162     for (int i = 0; i < args.length; i++)
 163       {
 164         if (args[i].equals("-d"))
 165           {
 166             decode = true;
 167           }
 168         else
 169           {
 170             try
 171               {
 172                 byte[] in = args[i].getBytes("US-ASCII");
 173                 byte[] out = decode ? decode(in) : encode(in);
 174                 System.out.println(args[i] + " = " +
 175                                    new String(out, "US-ASCII"));
 176               }
 177             catch (java.io.UnsupportedEncodingException e)
 178               {
 179                 e.printStackTrace(System.err);
 180               }
 181           }
 182       }
 183   }
 184 }