IpTranslator.java

package io.evercam.network.discovery;

import io.evercam.network.Constants;

import java.net.InetAddress;
import java.net.UnknownHostException;

public class IpTranslator {
    public static final String EMPTY_IP = "0.0.0.0";

    public static String getIpFromIntSigned(int ip_int) {
	String ip = "";
	for (int k = 0; k < 4; k++) {
	    ip = ip + ((ip_int >> k * 8) & 0xFF) + ".";
	}
	return ip.substring(0, ip.length() - 1);
    }

    public static String getIpFromLongUnsigned(long ip_long) {
	String ip = "";
	for (int k = 3; k > -1; k--) {
	    ip = ip + ((ip_long >> k * 8) & 0xFF) + ".";
	}
	return ip.substring(0, ip.length() - 1);
    }

    protected static long getUnsignedLongFromIp(String ip_addr)
	    throws Exception {

	if (ip_addr != null) {
	    String[] a = ip_addr.split("\\.");
	    return (Integer.parseInt(a[0]) * 16777216 + Integer.parseInt(a[1])
		    * 65536 + Integer.parseInt(a[2]) * 256 + Integer
			.parseInt(a[3]));
	} else {
	    throw new Exception("IP address can not be null");
	}
    }

    public static int maskIpToCidr(String ip) {
	double sum = -2;
	String[] part = ip.split("\\.");
	for (String p : part) {
	    sum += 256D - Double.parseDouble(p);
	}
	return 32 - (int) (Math.log(sum) / Math.log(2d));
    }

    public static String cidrToMask(int cidr) {
	int value = 0xffffffff << (32 - cidr);
	byte[] bytes = new byte[] { (byte) (value >>> 24),
		(byte) (value >> 16 & 0xff), (byte) (value >> 8 & 0xff),
		(byte) (value & 0xff) };

	InetAddress netAddr;
	try {
	    netAddr = InetAddress.getByAddress(bytes);
	    return netAddr.getHostAddress();
	} catch (UnknownHostException e) {
	    if (Constants.ENABLE_LOGGING) {
		e.printStackTrace();
	    }
	}

	return EMPTY_IP;
    }

    /** This method is not in use */
    public static boolean isValidIpv4Addr(String ip) {
	final String REGULAR_EXPRESSION_IP_V4 = "^(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[0-9]{1,2})(\\.(25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[0-9]{1,2})){3}$";
	return ip.matches(REGULAR_EXPRESSION_IP_V4);
    }

    public static boolean isLocalIpv4(String ip) {
	final String REGULAR_EXPRESSION_LOCAL_IP = "(127.0.0.1)|(192.168.*$)|(172.1[6-9].*$)|(172.2[0-9].*$)|(172.3[0-1].*$)|(10.*$)";
	return ip.matches(REGULAR_EXPRESSION_LOCAL_IP);
    }
}