presto-rcfile/src/main/java/io/prestosql/rcfile/binary/TimestampEncoding.java/TimestampEncoding/reverseDecimal
class TimestampEncoding:    private static int reverseDecimal(int nanos)
    {
        int decimal = 0;
        if (nanos != 0) {
            int counter = 0;
            while (counter < 9) {
                decimal *= 10;
                decimal += nanos % 10;
                nanos /= 10;
                counter++;
            }
        }
        return decimal;
    }