libjava/classpath/gnu/java/net/BASE64.java

   1 /* BASE.java --
   2    Copyright (C) 2003, 2004, 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.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      if (ti < bt.length)
 113       {
 114         byte[] tmp = new byte[ti];
 115         System.arraycopy(bt, 0, tmp, 0, ti);
 116         bt = tmp;
 117       }
 118     /*while (ti < bt.length)
 119       {
 120         bt[ti++] = 0x3d;
 121       }*/
 122     return bt;
 123   }
 124
 125   /**
 126    * Decode the specified byte array using the BASE64 algorithm.
 127    *
 128    * @param bs the source byte array
 129    */
 130   public static byte[] decode(byte[] bs)
 131   {
 132     int srclen = bs.length;
 133     while (srclen > 0 && bs[srclen - 1] == 0x3d)
 134       {
 135         srclen--; /* strip padding character */
 136       }
 137     byte[] buffer = new byte[srclen];
 138     int buflen = 0;
 139     int si = 0;
 140     int len = srclen - si;
 141     while (len > 0)
 142       {
 143         byte b0 = dst[bs[si++] & 0xff];
 144         byte b2 = dst[bs[si++] & 0xff];
 145         buffer[buflen++] = (byte) (b0 << 2 & 0xfc | b2 >>> 4 & 0x3);
 146         if (len > 2)
 147           {
 148             b0 = b2;
 149             b2 = dst[bs[si++] & 0xff];
 150             buffer[buflen++] = (byte) (b0 << 4 & 0xf0 | b2 >>> 2 & 0xf);
 151             if (len > 3)
 152               {
 153                 b0 = b2;
 154                 b2 = dst[bs[si++] & 0xff];
 155                 buffer[buflen++] = (byte) (b0 << 6 & 0xc0 | b2 & 0x3f);
 156               }
 157           }
 158         len = srclen - si;
 159       }
 160     byte[] bt = new byte[buflen];
 161     System.arraycopy(buffer, 0, bt, 0, buflen);
 162     return bt;
 163   }
 164
 165   public static void main(String[] args)
 166   {
 167     boolean decode = false;
 168     for (int i = 0; i < args.length; i++)
 169       {
 170         if (args[i].equals("-d"))
 171           {
 172             decode = true;
 173           }
 174         else
 175           {
 176             try
 177               {
 178                 byte[] in = args[i].getBytes("US-ASCII");
 179                 byte[] out = decode ? decode(in) : encode(in);
 180                 System.out.println(args[i] + " = " +
 181                                    new String(out, "US-ASCII"));
 182               }
 183             catch (java.io.UnsupportedEncodingException e)
 184               {
 185                 e.printStackTrace(System.err);
 186               }
 187           }
 188       }
 189   }
 190 }