Back to project page android-chat-telnet.
The source code is released under:
GNU Lesser General Public License
If you think the Android project android-chat-telnet listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at *// ww w . j a va 2 s .c o m * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.net.util; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * A class that performs some subnet calculations given a network address and a subnet mask. * @see "http://www.faqs.org/rfcs/rfc1519.html" * @author <rwinston@apache.org> * @since 2.0 */ public class SubnetUtils { private static final String IP_ADDRESS = "(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})"; private static final String SLASH_FORMAT = IP_ADDRESS + "/(\\d{1,3})"; private static final Pattern addressPattern = Pattern.compile(IP_ADDRESS); private static final Pattern cidrPattern = Pattern.compile(SLASH_FORMAT); private static final int NBITS = 32; private int netmask = 0; private int address = 0; private int network = 0; private int broadcast = 0; /** Whether the broadcast/network address are included in host count */ private boolean inclusiveHostCount = false; /** * Constructor that takes a CIDR-notation string, e.g. "192.168.0.1/16" * @param cidrNotation A CIDR-notation string, e.g. "192.168.0.1/16" * @throws IllegalArgumentException if the parameter is invalid, * i.e. does not match n.n.n.n/m where n=1-3 decimal digits, m = 1-3 decimal digits in range 1-32 */ public SubnetUtils(String cidrNotation) { calculate(cidrNotation); } /** * Constructor that takes a dotted decimal address and a dotted decimal mask. * @param address An IP address, e.g. "192.168.0.1" * @param mask A dotted decimal netmask e.g. "255.255.0.0" * @throws IllegalArgumentException if the address or mask is invalid, * i.e. does not match n.n.n.n where n=1-3 decimal digits and the mask is not all zeros */ public SubnetUtils(String address, String mask) { calculate(toCidrNotation(address, mask)); } /** * Returns <code>true</code> if the return value of {@link SubnetInfo#getAddressCount()} * includes the network address and broadcast addresses. * @since 2.2 */ public boolean isInclusiveHostCount() { return inclusiveHostCount; } /** * Set to <code>true</code> if you want the return value of {@link SubnetInfo#getAddressCount()} * to include the network and broadcast addresses. * @param inclusiveHostCount * @since 2.2 */ public void setInclusiveHostCount(boolean inclusiveHostCount) { this.inclusiveHostCount = inclusiveHostCount; } /** * Convenience container for subnet summary information. * */ public final class SubnetInfo { private SubnetInfo() {} private int netmask() { return netmask; } private int network() { return network; } private int address() { return address; } private int broadcast() { return broadcast; } private int low() { return (isInclusiveHostCount() ? network() : broadcast() - network() > 1 ? network() + 1 : 0); } private int high() { return (isInclusiveHostCount() ? broadcast() : broadcast() - network() > 1 ? broadcast() -1 : 0); } /** * Returns true if the parameter <code>address</code> is in the * range of usable endpoint addresses for this subnet. This excludes the * network and broadcast adresses. * @param address A dot-delimited IPv4 address, e.g. "192.168.0.1" * @return True if in range, false otherwise */ public boolean isInRange(String address) { return isInRange(toInteger(address)); } private boolean isInRange(int address) { int diff = address - low(); return (diff >= 0 && (diff <= (high() - low()))); } public String getBroadcastAddress() { return format(toArray(broadcast())); } public String getNetworkAddress() { return format(toArray(network())); } public String getNetmask() { return format(toArray(netmask())); } public String getAddress() { return format(toArray(address())); } /** * Return the low address as a dotted IP address. * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false. * * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address */ public String getLowAddress() { return format(toArray(low())); } /** * Return the high address as a dotted IP address. * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false. * * @return the IP address in dotted format, may be "0.0.0.0" if there is no valid address */ public String getHighAddress() { return format(toArray(high())); } /** * Get the count of available addresses. * Will be zero for CIDR/31 and CIDR/32 if the inclusive flag is false. * @return the count of addresses, may be zero. */ public int getAddressCount() { int count = broadcast() - network() + (isInclusiveHostCount() ? 1 : -1); return count < 0 ? 0 : count; } public int asInteger(String address) { return toInteger(address); } public String getCidrSignature() { return toCidrNotation( format(toArray(address())), format(toArray(netmask())) ); } public String[] getAllAddresses() { int ct = getAddressCount(); String[] addresses = new String[ct]; if (ct == 0) { return addresses; } for (int add = low(), j=0; add <= high(); ++add, ++j) { addresses[j] = format(toArray(add)); } return addresses; } /** * {@inheritDoc} * @since 2.2 */ @Override public String toString() { final StringBuilder buf = new StringBuilder(); buf.append("CIDR Signature:\t[").append(getCidrSignature()).append("]") .append(" Netmask: [").append(getNetmask()).append("]\n") .append("Network:\t[").append(getNetworkAddress()).append("]\n") .append("Broadcast:\t[").append(getBroadcastAddress()).append("]\n") .append("First Address:\t[").append(getLowAddress()).append("]\n") .append("Last Address:\t[").append(getHighAddress()).append("]\n") .append("# Addresses:\t[").append(getAddressCount()).append("]\n"); return buf.toString(); } } /** * Return a {@link SubnetInfo} instance that contains subnet-specific statistics * @return new instance */ public final SubnetInfo getInfo() { return new SubnetInfo(); } /* * Initialize the internal fields from the supplied CIDR mask */ private void calculate(String mask) { Matcher matcher = cidrPattern.matcher(mask); if (matcher.matches()) { address = matchAddress(matcher); /* Create a binary netmask from the number of bits specification /x */ int cidrPart = rangeCheck(Integer.parseInt(matcher.group(5)), 0, NBITS); for (int j = 0; j < cidrPart; ++j) { netmask |= (1 << 31-j); } /* Calculate base network address */ network = (address & netmask); /* Calculate broadcast address */ broadcast = network | ~(netmask); } else { throw new IllegalArgumentException("Could not parse [" + mask + "]"); } } /* * Convert a dotted decimal format address to a packed integer format */ private int toInteger(String address) { Matcher matcher = addressPattern.matcher(address); if (matcher.matches()) { return matchAddress(matcher); } else { throw new IllegalArgumentException("Could not parse [" + address + "]"); } } /* * Convenience method to extract the components of a dotted decimal address and * pack into an integer using a regex match */ private int matchAddress(Matcher matcher) { int addr = 0; for (int i = 1; i <= 4; ++i) { int n = (rangeCheck(Integer.parseInt(matcher.group(i)), -1, 255)); addr |= ((n & 0xff) << 8*(4-i)); } return addr; } /* * Convert a packed integer address into a 4-element array */ private int[] toArray(int val) { int ret[] = new int[4]; for (int j = 3; j >= 0; --j) { ret[j] |= ((val >>> 8*(3-j)) & (0xff)); } return ret; } /* * Convert a 4-element array into dotted decimal format */ private String format(int[] octets) { StringBuilder str = new StringBuilder(); for (int i =0; i < octets.length; ++i){ str.append(octets[i]); if (i != octets.length - 1) { str.append("."); } } return str.toString(); } /* * Convenience function to check integer boundaries. * Checks if a value x is in the range (begin,end]. * Returns x if it is in range, throws an exception otherwise. */ private int rangeCheck(int value, int begin, int end) { if (value > begin && value <= end) { // (begin,end] return value; } throw new IllegalArgumentException("Value [" + value + "] not in range ("+begin+","+end+"]"); } /* * Count the number of 1-bits in a 32-bit integer using a divide-and-conquer strategy * see Hacker's Delight section 5.1 */ int pop(int x) { x = x - ((x >>> 1) & 0x55555555); x = (x & 0x33333333) + ((x >>> 2) & 0x33333333); x = (x + (x >>> 4)) & 0x0F0F0F0F; x = x + (x >>> 8); x = x + (x >>> 16); return x & 0x0000003F; } /* Convert two dotted decimal addresses to a single xxx.xxx.xxx.xxx/yy format * by counting the 1-bit population in the mask address. (It may be better to count * NBITS-#trailing zeroes for this case) */ private String toCidrNotation(String addr, String mask) { return addr + "/" + pop(toInteger(mask)); } }