code: public static final BigInteger bytesToBigInteger( byte[] data, int[] offset ) {
          int length = bytesToInt(data, offset);
          byte[] bytes = new byte[length];
          offset[0] += memcpy(bytes, 0, data, offset[0], length);
  
          return new BigInteger(bytes);
      }
docs: Return the <code>BigInteger</code> represented by the bytes in
  <code>data</code> staring at offset <code>offset[0]</code>.
  
  @param data the array from which to read
  @param offset A single element array whose first element is the index in
  data from which to begin reading on  function entry, and which
  on function exit has been incremented by the number of bytes
  read.
  
  @return the <code>BigInteger</code> decoded