Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
//License from project: Apache License 

import java.net.InetAddress;

public class Main {
    /**
     * @return positive - current is better, 0 - cannot tell from MAC addr, negative - candidate is better.
     */
    private static int compareAddresses(byte[] current, byte[] candidate) {
        if (candidate == null) {
            return 1;
        }

        // Must be EUI-48 or longer.
        if (candidate.length < 6) {
            return 1;
        }

        // Must not be filled with only 0 and 1.
        boolean onlyZeroAndOne = true;
        for (byte b : candidate) {
            if (b != 0 && b != 1) {
                onlyZeroAndOne = false;
                break;
            }
        }

        if (onlyZeroAndOne) {
            return 1;
        }

        // Must not be a multicast address
        if ((candidate[0] & 1) != 0) {
            return 1;
        }

        // Prefer globally unique address.
        if ((current[0] & 2) == 0) {
            if ((candidate[0] & 2) == 0) {
                // Both current and candidate are globally unique addresses.
                return 0;
            } else {
                // Only current is globally unique.
                return 1;
            }
        } else {
            if ((candidate[0] & 2) == 0) {
                // Only candidate is globally unique.
                return -1;
            } else {
                // Both current and candidate are non-unique.
                return 0;
            }
        }
    }

    /**
     * @return positive - current is better, 0 - cannot tell, negative - candidate is better
     */
    private static int compareAddresses(InetAddress current, InetAddress candidate) {
        return scoreAddress(current) - scoreAddress(candidate);
    }

    private static int scoreAddress(InetAddress addr) {
        if (addr.isAnyLocalAddress()) {
            return 0;
        }
        if (addr.isMulticastAddress()) {
            return 1;
        }
        if (addr.isLinkLocalAddress()) {
            return 2;
        }
        if (addr.isSiteLocalAddress()) {
            return 3;
        }

        return 4;
    }
}