Method compare

src/main/java/core/org/xbill/DNS/Serial.java:30–42

Compares two numbers using serial arithmetic. The numbers are assumed to be 32 bit unsigned integers stored in longs. @param serial1 The first integer @param serial2 The second integer @return 0 if the 2 numbers are equal, a positive number if serial1 is greater than serial2, and a negative number

(long serial1, long serial2)

 * @throws IllegalArgumentException serial1 or serial2 is out of range
 */
public static int
compare(long serial1, long serial2) {
	if (serial1 < 0 || serial1 > MAX32)
		throw new IllegalArgumentException(serial1 + " out of range");
	if (serial2 < 0 || serial2 > MAX32)
		throw new IllegalArgumentException(serial2 + " out of range");
	long diff = serial1 - serial2;
	if (diff >= MAX32)
		diff -= (MAX32 + 1);
	else if (diff < -MAX32)
		diff += (MAX32 + 1);
	return (int)diff;
}

/**
 * Increments a serial number.  The number is assumed to be a 32 bit unsigned