docs: public String getSubString(long pos,
                                 final int length) throws SQLException {
  
          final String ldata = data;
  
          checkValid(ldata);
  
          final int dlen = ldata.length();
  
          if (pos < MIN_POS || pos > dlen) {
              Util.outOfRangeArgument("pos: " + pos);
          }
          pos--;
  
          if (length < 0 || length > dlen - pos) {
              throw Util.outOfRangeArgument("length: " + length);
          }
  
          return (pos == 0 && length == dlen) ? ldata
                  : ldata.substring((int) pos, (int) pos + length);
      }