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// Copyright (c) 2003-2004 Brian Wellington (bwelling@xbill.org)
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* Helper functions for doing serial arithmetic. These should be used when
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* setting/checking SOA serial numbers. SOA serial number arithmetic is
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* @author Brian Wellington
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public final class Serial {
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private static final long MAX32 = 0xFFFFFFFFL;
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* Compares two numbers using serial arithmetic. The numbers are assumed
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* to be 32 bit unsigned integers stored in longs.
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* @param serial1 The first integer
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* @param serial2 The second integer
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* @return 0 if the 2 numbers are equal, a positive number if serial1 is greater
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* than serial2, and a negative number if serial2 is greater than serial1.
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* @throws IllegalArgumentException serial1 or serial2 is out of range
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compare(long serial1, long serial2) {
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if (serial1 < 0 || serial1 > MAX32)
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throw new IllegalArgumentException(serial1 + " out of range");
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if (serial2 < 0 || serial2 > MAX32)
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throw new IllegalArgumentException(serial2 + " out of range");
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long diff = serial1 - serial2;
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else if (diff < -MAX32)
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* Increments a serial number. The number is assumed to be a 32 bit unsigned
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* integer stored in a long. This basically adds 1 and resets the value to
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* @param serial The serial number
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* @return The incremented serial number
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* @throws IllegalArgumentException serial is out of range
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increment(long serial) {
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if (serial < 0 || serial > MAX32)
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throw new IllegalArgumentException(serial + " out of range");
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removed
org/xbill/DNS/Serial.java
