Method convert

base/src/main/java/net/time4j/ClockUnit.java:216–240

(
        long sourceDuration,
        ClockUnit sourceUnit
    )

     * @throws  ArithmeticException in case of long overflow
     */
    public long convert(
        long sourceDuration,
        ClockUnit sourceUnit
    ) {

        if (sourceDuration == 0) {
            return 0L;
        }

        int o1 = this.ordinal();
        int o2 = sourceUnit.ordinal();

        if (o1 == o2) {
            return sourceDuration;
        } else if (o1 > o2) {
            return MathUtils.safeMultiply(
                sourceDuration,
                FACTORS[o1] / FACTORS[o2]
            );
        } else {
            long factor = FACTORS[o2] / FACTORS[o1];
            return (sourceDuration / factor); // possible truncation
        }

    }

    /**
     * <p>Converts the given duration to an amount in this unit and performs