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.*;
   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) throws IOException {
  35         if(args.length == 2 && args[0].equals("encode"))
  36             System.out.println(encode(getBytes(args[1])));
  37         else if(args.length == 2 && args[0].equals("decode"))
  38             System.out.write(decode(args[1]));
  39         else if(args.length == 2 && args[0].equals("encodefile")) {
  40             FileInputStream fis = new FileInputStream(args[1]);
  41             ByteArrayOutputStream baos = new ByteArrayOutputStream();
  42             byte[] buf = new byte[4096];
  43             int n;
  44             while((n = fis.read(buf)) != -1) baos.write(buf,0,n);
  45             fis.close();
  46             System.out.println(encode(baos.toByteArray()));
  47         } else {
  48             System.out.println("Usage: Base64 {encode,decode} filename");
  49             System.exit(1);
  50         }
  51         System.exit(0);
  52     }
  53
  54     public static byte[] decode(String inString){
  55         char[] in = inString.toCharArray();
  56         int part=0;
  57         int theBytes = 0;
  58         byte[] out = new byte[in.length / 4 * 3];
  59         int outPos = 0;
  60         for(int i=0;i<in.length;i++){
  61             int x = decodeMap[in[i] & 0x7f];
  62             if(x == -1) continue;
  63             if(x == -2) break;
  64             theBytes = (theBytes << 6) | x;
  65             part++;
  66             if(part == 4){
  67                 part = 0;
  68                 out[outPos++] = (byte)((theBytes >>> 16) & 0xff);
  69                 out[outPos++] = (byte)((theBytes >>>  8) & 0xff);
  70                 out[outPos++] = (byte)((theBytes >>>  0) & 0xff);
  71             }
  72         }
  73         switch(part){
  74             case 3:
  75                 out[outPos++] = (byte)((theBytes >>> 10) & 0xff);
  76                 out[outPos++] = (byte)((theBytes >>> 2) & 0xff);
  77                 break;
  78             case 2:
  79                 out[outPos++] = (byte)((theBytes >> 4) & 0xff);
  80                 break;
  81         }
  82
  83         if(outPos < out.length){
  84             byte[] a = new byte[outPos];
  85             System.arraycopy(out,0,a,0,outPos);
  86             return a;
  87         } else {
  88             return out;
  89         }
  90     }
  91
  92     public static String encode(String in) { return encode(getBytes(in)); }
  93
  94     public static String encode(byte[] in){
  95         int part=0;
  96         int theBytes = 0;
  97         char[] out = new char[(in.length / 3 + 1) * 4];
  98         int outPos = 0;
  99         for(int i=0;i<in.length;i++){
 100             theBytes = (theBytes << 8) | (in[i]&0xff);
 101             part++;
 102             if(part == 3){
 103                 part = 0;
 104                 out[outPos++] = encodeMap[(theBytes >>> 18) & 0x3f];
 105                 out[outPos++] = encodeMap[(theBytes >>> 12) & 0x3f];
 106                 out[outPos++] = encodeMap[(theBytes >>>  6) & 0x3f];
 107                 out[outPos++] = encodeMap[(theBytes >>>  0) & 0x3f];
 108             }
 109         }
 110         switch(part){
 111             case 2:
 112                 out[outPos++] = encodeMap[(theBytes >>>  10) & 0x3f];
 113                 out[outPos++] = encodeMap[(theBytes >>>  4)  & 0x3f];
 114                 out[outPos++] = encodeMap[(theBytes <<   2)  & 0x3f];
 115                 out[outPos++] = '=';
 116                 break;
 117             case 1:
 118                 out[outPos++] = encodeMap[(theBytes >>> 2) & 0x3f];
 119                 out[outPos++] = encodeMap[(theBytes <<  4) & 0x3f];
 120                 out[outPos++] = '=';
 121                 out[outPos++] = '=';
 122                 break;
 123         }
 124         return new String(out,0,outPos);
 125     }
 126
 127     public static byte[] getBytes(String s) {
 128         try {
 129                 return s.getBytes("US-ASCII");
 130         } catch (UnsupportedEncodingException e) {
 131                 throw new Error("should never happen");
 132         }
 133     }
 134 }