Main.java Source code

Introduction

Here is the source code for Main.java

Source

//package com.java2s;
/*
 *  PHEX - The pure-java Gnutella-servent.
 *  Copyright (C) 2001 - 2008 Phex Development Group
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 * 
 *  --- SVN Information ---
 *  $Id$
 */

public class Main {
    /**
     * Parses a netmask. This can either be in ip format (xxx.xxx.xxx.xxx)
     * or an int when using CIDR notation
     * @param netmask
     * @return
     */
    public static byte parseNetmaskToCidr(String netmask) {
        if (netmask.indexOf('.') == -1) { // CIDR notation
            try {
                byte val = Byte.parseByte(netmask);
                if (val >= 0) {
                    return val;
                }
                throw new IllegalArgumentException("Invalid netmask: " + netmask);
            } catch (NumberFormatException exp) {
                throw new IllegalArgumentException("Invalid netmask: " + netmask);
            }
        } else {// simple ip notation
            return calculateCidr(parseDottedIpToInt(netmask));
        }
    }

    /**
     * Calculates the cidr from an netmask IP.
     * @param ip the IP to calculate the cidr for.
     * @return the cidr value of the IP.
     */
    public static byte calculateCidr(int ip) {
        byte b = 0;

        b += cidrByteToNBits((byte) ((ip >>> 24) & 0xFF));
        b += cidrByteToNBits((byte) ((ip >>> 16) & 0xFF));
        b += cidrByteToNBits((byte) ((ip >>> 8) & 0xFF));
        b += cidrByteToNBits((byte) (ip & 0xFF));

        return b;
    }

    /**
     * Calculates the cidr from an netmask IP.
     * @param ip the IP to calculate the cidr for.
     * @return the cidr value of the IP.
     */
    public static byte calculateCidr(byte[] ip) {
        int intIp = byteIpToIntIp(ip);
        return calculateCidr(intIp);
    }

    /**
     * Parses an ip in the format xxx.xxx.xxx.xxx into an int value.
     * @param hostIp
     * @return
     */
    public static int parseDottedIpToInt(String hostIp) {
        /* The string (probably) represents a numerical IP address.
         * Parse it into an int, don't do uneeded reverese lookup,
         * leave hostName null, don't cache.  If it isn't an IP address,
         * (i.e., not "%d.%d.%d.%d") or if any element > 0xFF,
         * it is a hostname and we return null.
         * This seems to be 100% compliant to the RFC1123 spec.
         */
        String ipToParse;
        int portSeparatorIdx = hostIp.indexOf(':');
        if (portSeparatorIdx != -1) {// cut of port.
            ipToParse = hostIp.substring(0, portSeparatorIdx);
        } else {
            ipToParse = hostIp;
        }

        char[] data = ipToParse.toCharArray();
        int IP = 0x00;
        int hitDots = 0;

        for (int i = 0; i < data.length; i++) {
            char c = data[i];
            if (c < 48 || c > 57) { // !digit
                throw new IllegalArgumentException("IP contains character: " + ipToParse + " - org: " + hostIp);
            }
            int b = 0x00;
            while (c != '.') {
                //      '0'       '9'
                if (c < 48 || c > 57) { // !digit
                    throw new IllegalArgumentException("IP contains character: " + ipToParse);
                }
                b = b * 10 + c - '0';

                if (++i >= data.length) {
                    break;
                }
                c = data[i];
            }
            if (b > 0xFF) { /* bogus - bigger than a byte */
                throw new IllegalArgumentException("Bogus ip value: " + ipToParse);
            }
            IP = (IP << 8) + b;
            hitDots++;
        }
        if (hitDots != 4 || ipToParse.endsWith(".")) {
            throw new IllegalArgumentException("Bogus ip: " + ipToParse);
        }

        return IP;
    }

    private static byte cidrByteToNBits(byte val) {
        switch (val) {
        case (byte) 0xFF:
            return 8;
        case (byte) 0xFE:
            return 7;
        case (byte) 0xFC:
            return 6;
        case (byte) 0xF8:
            return 5;
        case (byte) 0xF0:
            return 4;
        case (byte) 0xE0:
            return 3;
        case (byte) 0xC0:
            return 2;
        case (byte) 0x80:
            return 1;
        case (byte) 0x00:
            return 0;
        }
        throw new IllegalArgumentException("Invalid byte value");
    }

    public static int byteIpToIntIp(byte[] ip) {
        int v1 = ip[3] & 0xFF;
        int v2 = (ip[2] << 8) & 0xFF00;
        int v3 = (ip[1] << 16) & 0xFF0000;
        int v4 = (ip[0] << 24);
        int ipValue = ((v4 | v3 | v2 | v1)) & 0xFFFFFFFF;
        return ipValue;
    }
}