src/org/ibex/crypto/Base64.java

   1 /*
   2  * org.ibex.crypto.Base64 - By Brian Alliet
   3  * Copyright (C) 2004 Brian Alliet
   4  */
   5 package org.ibex.crypto;
   6
   7 import java.io.UnsupportedEncodingException;
   8
   9 public final class Base64 {
  10         private Base64() { /* can't be instansiated */ }
  11
  12     private static final char encodeMap[] = {
  13         'A','B','C','D','E','F','G','H',
  14         'I','J','K','L','M','N','O','P',
  15         'Q','R','S','T','U','V','W','X',
  16         'Y','Z','a','b','c','d','e','f',
  17         'g','h','i','j','k','l','m','n',
  18         'o','p','q','r','s','t','u','v',
  19         'w','x','y','z','0','1','2','3',
  20         '4','5','6','7','8','9','+','/'
  21     };
  22
  23     private static final int decodeMap[] = {
  24         -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  25         -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
  26         -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,62,-1,-1,-1,63,
  27         52,53,54,55,56,57,58,59,60,61,-1,-1,-1,-2,-1,-1,
  28         -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,
  29         15,16,17,18,19,20,21,22,23,24,25,-1,-1,-1,-1,-1,
  30         -1,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
  31         41,42,43,44,45,46,47,48,49,50,51,-1,-1,-1,-1,-1
  32     };
  33
  34         public static void main(String[] args){
  35         if(args.length == 2 && args[0].equals("encode"))
  36             System.out.println(encode(args[1].getBytes()));
  37         else if(args.length == 2 && args[0].equals("decode"))
  38             System.out.println(new String(decode(args[1])));
  39         else {
  40             System.out.println("Usage: Base64 {encode,decode} text");
  41             System.exit(1);
  42         }
  43         System.exit(0);
  44         }
  45
  46         public static byte[] decode(String inString){
  47         char[] in = inString.toCharArray();
  48         int part=0;
  49         int theBytes = 0;
  50         byte[] out = new byte[in.length / 4 * 3];
  51         int outPos = 0;
  52         for(int i=0;i<in.length;i++){
  53             int x = decodeMap[in[i] & 0x7f];
  54             if(x == -1) continue;
  55             if(x == -2) break;
  56             theBytes = (theBytes << 6) | x;
  57             part++;
  58             if(part == 4){
  59                 part = 0;
  60                 out[outPos++] = (byte)((theBytes >>> 16) & 0xff);
  61                 out[outPos++] = (byte)((theBytes >>>  8) & 0xff);
  62                 out[outPos++] = (byte)((theBytes >>>  0) & 0xff);
  63             }
  64         }
  65         switch(part){
  66             case 3:
  67                 out[outPos++] = (byte)((theBytes >>> 10) & 0xff);
  68                 out[outPos++] = (byte)((theBytes >>> 2) & 0xff);
  69                 break;
  70             case 2:
  71                 out[outPos++] = (byte)((theBytes >> 4) & 0xff);
  72                 break;
  73         }
  74
  75         if(outPos < out.length){
  76             byte[] a = new byte[outPos];
  77             System.arraycopy(out,0,a,0,outPos);
  78             return a;
  79         } else {
  80             return out;
  81         }
  82     }
  83
  84         public static String encode(String in) { return encode(getBytes(in)); }
  85     public static String encode(byte[] in){
  86         int part=0;
  87         int theBytes = 0;
  88         char[] out = new char[(in.length / 3 + 1) * 4];
  89         int outPos = 0;
  90         for(int i=0;i<in.length;i++){
  91             theBytes = (theBytes << 8) | in[i];
  92             part++;
  93             if(part == 3){
  94                 part = 0;
  95                 out[outPos++] = encodeMap[(theBytes >>> 18) & 0x3f];
  96                 out[outPos++] = encodeMap[(theBytes >>> 12) & 0x3f];
  97                 out[outPos++] = encodeMap[(theBytes >>>  6) & 0x3f];
  98                 out[outPos++] = encodeMap[(theBytes >>>  0) & 0x3f];
  99             }
 100         }
 101         switch(part){
 102             case 2:
 103                 out[outPos++] = encodeMap[(theBytes >>>  10) & 0x3f];
 104                 out[outPos++] = encodeMap[(theBytes >>>  4)  & 0x3f];
 105                 out[outPos++] = encodeMap[(theBytes <<   2)  & 0x3f];
 106                 out[outPos++] = '=';
 107                 break;
 108             case 1:
 109                 out[outPos++] = encodeMap[(theBytes >>> 2) & 0x3f];
 110                 out[outPos++] = encodeMap[(theBytes <<  4) & 0x3f];
 111                 out[outPos++] = '=';
 112                 out[outPos++] = '=';
 113                 break;
 114         }
 115         return new String(out,0,outPos);
 116     }
 117
 118     public static byte[] getBytes(String s) {
 119         try {
 120                 return s.getBytes("US-ASCII");
 121         } catch (UnsupportedEncodingException e) {
 122                 throw new Error("should never happen");
 123         }
 124     }
 125 }