public static int decodeChar(char c) throws Base85FormatException {
    // optimization for 2-byte char size
    if (c < ASCII_LEFT_SHIFT || c > ASCII_RIGHT_SHIFT) {
      throw new Base85FormatException("Illegal char " + (int)c);
    }
    int result = INDEX_OF[c];
    if (result == -1) {
      throw new Base85FormatException("Illegal char " + (int)c);
    }
    return result;
  }
public static int decodeChar(char c)