package org.rpi.plugin.lastfm;
   public class Base64 {
   
       private final static char[] ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
   
       private static int[]  toInt   = new int[128];
   
       static {
           for(int i=0; i< ALPHABET.length; i++){
              toInt[ALPHABET[i]]= i;
          }
      }
  
      /**
       * Translates the specified byte array into Base64 string.
       *
       * @param buf the byte array (not null)
       * @return the translated Base64 string (not null)
       */
      public static String encode(byte[] buf){
          int size = buf.length;
          char[] ar = new char[((size + 2) / 3) * 4];
          int a = 0;
          int i=0;
          while(i < size){
              byte b0 = buf[i++];
              byte b1 = (i < size) ? buf[i++] : 0;
              byte b2 = (i < size) ? buf[i++] : 0;
  
              int mask = 0x3F;
              ar[a++] = ALPHABET[(b0 >> 2) & mask];
              ar[a++] = ALPHABET[((b0 << 4) | ((b1 & 0xFF) >> 4)) & mask];
              ar[a++] = ALPHABET[((b1 << 2) | ((b2 & 0xFF) >> 6)) & mask];
              ar[a++] = ALPHABET[b2 & mask];
          }
          switch(size % 3){
              case 1: ar[--a]  = '=';
              case 2: ar[--a]  = '=';
          }
          return new String(ar);
      }
  
      /**
       * Translates the specified Base64 string into a byte array.
       *
       * @param s the Base64 string (not null)
       * @return the byte array (not null)
       */
      public static byte[] decode(String s){
          int delta = s.endsWith( "==" ) ? 2 : s.endsWith( "=" ) ? 1 : 0;
          byte[] buffer = new byte[s.length()*3/4 - delta];
          int mask = 0xFF;
          int index = 0;
          for(int i=0; i< s.length(); i+=4){
              int c0 = toInt[s.charAt( i )];
              int c1 = toInt[s.charAt( i + 1)];
              buffer[index++]= (byte)(((c0 << 2) | (c1 >> 4)) & mask);
              if(index >= buffer.length){
                  return buffer;
              }
              int c2 = toInt[s.charAt( i + 2)];
              buffer[index++]= (byte)(((c1 << 4) | (c2 >> 2)) & mask);
              if(index >= buffer.length){
                  return buffer;
              }
              int c3 = toInt[s.charAt( i + 3 )];
              buffer[index++]= (byte)(((c2 << 6) | c3) & mask);
          }
          return buffer;
      }
  
  }