presto-spi/src/main/java/io/prestosql/spi/type/UnscaledDecimal128Arithmetic.java/UnscaledDecimal128Arithmetic/unscaledDecimalToUnscaledLongUnsafe
class UnscaledDecimal128Arithmetic:    public static long unscaledDecimalToUnscaledLongUnsafe(Slice decimal)
    {
        long low = getLong(decimal, 0);
        return isNegative(decimal) ? -low : low;
    }