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Smack/source/org/jivesoftware/smack/util/StringUtils.java

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/**
* $RCSfile$
* $Revision$
* $Date$
*
* Copyright (C) 2002-2003 Jive Software. All rights reserved.
* ====================================================================
* The Jive Software License (based on Apache Software License, Version 1.1)
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by
* Jive Software (http://www.jivesoftware.com)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Smack" and "Jive Software" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please
* contact webmaster@jivesoftware.com.
*
* 5. Products derived from this software may not be called "Smack",
* nor may "Smack" appear in their name, without prior written
* permission of Jive Software.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL JIVE SOFTWARE OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*/
package org.jivesoftware.smack.util;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.io.UnsupportedEncodingException;
import java.util.Random;
/**
* A collection of utility methods for String objects.
*/
public class StringUtils {
private static final char[] QUOTE_ENCODE = """.toCharArray();
private static final char[] AMP_ENCODE = "&".toCharArray();
private static final char[] LT_ENCODE = "<".toCharArray();
private static final char[] GT_ENCODE = ">".toCharArray();
/**
* Returns the name portion of a XMPP address. For example, for the
* address "matt@jivesoftware.com/Smack", "matt" would be returned. If no
* username is present in the address, the empty string will be returned.
*
* @param XMPPAddress the XMPP address.
* @return the name portion of the XMPP address.
*/
public static String parseName(String XMPPAddress) {
if (XMPPAddress == null) {
return null;
}
int atIndex = XMPPAddress.indexOf("@");
if (atIndex <= 0) {
return "";
}
else {
return XMPPAddress.substring(0, atIndex);
}
}
/**
* Returns the server portion of a XMPP address. For example, for the
* address "matt@jivesoftware.com/Smack", "jivesoftware.com" would be returned.
* If no server is present in the address, the empty string will be returned.
*
* @param XMPPAddress the XMPP address.
* @return the server portion of the XMPP address.
*/
public static String parseServer(String XMPPAddress) {
if (XMPPAddress == null) {
return null;
}
int atIndex = XMPPAddress.indexOf("@");
// If the String ends with '@', return the empty string.
if (atIndex + 1 > XMPPAddress.length()) {
return "";
}
int slashIndex = XMPPAddress.indexOf("/");
if (slashIndex > 0) {
return XMPPAddress.substring(atIndex + 1, slashIndex);
}
else {
return XMPPAddress.substring(atIndex + 1);
}
}
/**
* Returns the resource portion of a XMPP address. For example, for the
* address "matt@jivesoftware.com/Smack", "Smack" would be returned. If no
* resource is present in the address, the empty string will be returned.
*
* @param XMPPAddress the XMPP address.
* @return the resource portion of the XMPP address.
*/
public static String parseResource(String XMPPAddress) {
if (XMPPAddress == null) {
return null;
}
int slashIndex = XMPPAddress.indexOf("/");
if (slashIndex + 1 > XMPPAddress.length() || slashIndex < 0) {
return "";
}
else {
return XMPPAddress.substring(slashIndex + 1);
}
}
/**
* Returns the XMPP address with any resource information removed. For example,
* for the address "matt@jivesoftware.com/Smack", "matt@jivesoftware.com" would
* be returned.
*
* @param XMPPAddress the XMPP address.
* @return the bare XMPP address without resource information.
*/
public static String parseBareAddress(String XMPPAddress) {
if (XMPPAddress == null) {
return null;
}
int slashIndex = XMPPAddress.indexOf("/");
if (slashIndex < 0) {
return XMPPAddress;
}
else if (slashIndex == 0) {
return "";
}
else {
return XMPPAddress.substring(0, slashIndex);
}
}
/**
* Escapes all necessary characters in the String so that it can be used
* in an XML doc.
*
* @param string the string to escape.
* @return the string with appropriate characters escaped.
*/
public static final String escapeForXML(String string) {
if (string == null) {
return null;
}
char ch;
int i=0;
int last=0;
char[] input = string.toCharArray();
int len = input.length;
StringBuffer out = new StringBuffer((int)(len*1.3));
for (; i < len; i++) {
ch = input[i];
if (ch > '>') {
continue;
}
else if (ch == '<') {
if (i > last) {
out.append(input, last, i - last);
}
last = i + 1;
out.append(LT_ENCODE);
}
else if (ch == '>') {
if (i > last) {
out.append(input, last, i - last);
}
last = i + 1;
out.append(GT_ENCODE);
}
else if (ch == '&') {
if (i > last) {
out.append(input, last, i - last);
}
// Do nothing if the string is of the form &#235; (unicode value)
if (!(len > i + 5
&& input[i + 1] == '#'
&& Character.isDigit(input[i + 2])
&& Character.isDigit(input[i + 3])
&& Character.isDigit(input[i + 4])
&& input[i + 5] == ';')) {
last = i + 1;
out.append(AMP_ENCODE);
}
}
else if (ch == '"') {
if (i > last) {
out.append(input, last, i - last);
}
last = i + 1;
out.append(QUOTE_ENCODE);
}
}
if (last == 0) {
return string;
}
if (i > last) {
out.append(input, last, i - last);
}
return out.toString();
}
/**
* Used by the hash method.
*/
private static MessageDigest digest = null;
/**
* Hashes a String using the SHA-1 algorithm and returns the result as a
* String of hexadecimal numbers. This method is synchronized to avoid
* excessive MessageDigest object creation. If calling this method becomes
* a bottleneck in your code, you may wish to maintain a pool of
* MessageDigest objects instead of using this method.
* <p>
* A hash is a one-way function -- that is, given an
* input, an output is easily computed. However, given the output, the
* input is almost impossible to compute. This is useful for passwords
* since we can store the hash and a hacker will then have a very hard time
* determining the original password.
*
* @param data the String to compute the hash of.
* @return a hashed version of the passed-in String
*/
public synchronized static final String hash(String data) {
if (digest == null) {
try {
digest = MessageDigest.getInstance("SHA-1");
}
catch (NoSuchAlgorithmException nsae) {
System.err.println("Failed to load the SHA-1 MessageDigest. " +
"Jive will be unable to function normally.");
}
}
// Now, compute hash.
try {
digest.update(data.getBytes("UTF-8"));
}
catch (UnsupportedEncodingException e) {
System.err.println(e);
}
return encodeHex(digest.digest());
}
/**
* Turns an array of bytes into a String representing each byte as an
* unsigned hex number.
* <p>
* Method by Santeri Paavolainen, Helsinki Finland 1996<br>
* (c) Santeri Paavolainen, Helsinki Finland 1996<br>
* Distributed under LGPL.
*
* @param bytes an array of bytes to convert to a hex-string
* @return generated hex string
*/
public static final String encodeHex(byte[] bytes) {
StringBuffer buf = new StringBuffer(bytes.length * 2);
int i;
for (i = 0; i < bytes.length; i++) {
if (((int) bytes[i] & 0xff) < 0x10) {
buf.append("0");
}
buf.append(Long.toString((int) bytes[i] & 0xff, 16));
}
return buf.toString();
}
//*********************************************************************
//* Base64 - a simple base64 encoder and decoder.
//*
//* Copyright (c) 1999, Bob Withers - bwit@pobox.com
//*
//* This code may be freely used for any purpose, either personal
//* or commercial, provided the authors copyright notice remains
//* intact.
//*********************************************************************
private static final int fillchar = '=';
private static final String cvt = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+ "0123456789+/";
/**
* Encodes a String as a base64 String.
*
* @param data a String to encode.
* @return a base64 encoded String.
*/
public static String encodeBase64(String data) {
byte [] bytes = null;
try {
bytes = data.getBytes("ISO-8859-1");
}
catch (UnsupportedEncodingException uee) {
uee.printStackTrace();
}
return encodeBase64(bytes);
}
/**
* Encodes a byte array into a base64 String.
*
* @param data a byte array to encode.
* @return a base64 encode String.
*/
public static String encodeBase64(byte[] data) {
int c;
int len = data.length;
StringBuffer ret = new StringBuffer(((len / 3) + 1) * 4);
for (int i = 0; i < len; ++i) {
c = (data[i] >> 2) & 0x3f;
ret.append(cvt.charAt(c));
c = (data[i] << 4) & 0x3f;
if (++i < len)
c |= (data[i] >> 4) & 0x0f;
ret.append(cvt.charAt(c));
if (i < len) {
c = (data[i] << 2) & 0x3f;
if (++i < len)
c |= (data[i] >> 6) & 0x03;
ret.append(cvt.charAt(c));
}
else {
++i;
ret.append((char) fillchar);
}
if (i < len) {
c = data[i] & 0x3f;
ret.append(cvt.charAt(c));
}
else {
ret.append((char) fillchar);
}
}
return ret.toString();
}
/**
* Decodes a base64 String.
*
* @param data a base64 encoded String to decode.
* @return the decoded String.
*/
public static byte[] decodeBase64(String data) {
byte [] bytes = null;
try {
bytes = data.getBytes("ISO-8859-1");
return decodeBase64(bytes).getBytes("ISO-8859-1");
}
catch (UnsupportedEncodingException uee) {
uee.printStackTrace();
}
return new byte[] { };
}
/**
* Decodes a base64 aray of bytes.
*
* @param data a base64 encode byte array to decode.
* @return the decoded String.
*/
private static String decodeBase64(byte[] data) {
int c, c1;
int len = data.length;
StringBuffer ret = new StringBuffer((len * 3) / 4);
for (int i = 0; i < len; ++i) {
c = cvt.indexOf(data[i]);
++i;
c1 = cvt.indexOf(data[i]);
c = ((c << 2) | ((c1 >> 4) & 0x3));
ret.append((char) c);
if (++i < len) {
c = data[i];
if (fillchar == c)
break;
c = cvt.indexOf(c);
c1 = ((c1 << 4) & 0xf0) | ((c >> 2) & 0xf);
ret.append((char) c1);
}
if (++i < len) {
c1 = data[i];
if (fillchar == c1)
break;
c1 = cvt.indexOf(c1);
c = ((c << 6) & 0xc0) | c1;
ret.append((char) c);
}
}
return ret.toString();
}
/**
* Pseudo-random number generator object for use with randomString().
* The Random class is not considered to be cryptographically secure, so
* only use these random Strings for low to medium security applications.
*/
private static Random randGen = new Random();
/**
* Array of numbers and letters of mixed case. Numbers appear in the list
* twice so that there is a more equal chance that a number will be picked.
* We can use the array to get a random number or letter by picking a random
* array index.
*/
private static char[] numbersAndLetters = ("0123456789abcdefghijklmnopqrstuvwxyz" +
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();
/**
* Returns a random String of numbers and letters (lower and upper case)
* of the specified length. The method uses the Random class that is
* built-in to Java which is suitable for low to medium grade security uses.
* This means that the output is only pseudo random, i.e., each number is
* mathematically generated so is not truly random.<p>
*
* The specified length must be at least one. If not, the method will return
* null.
*
* @param length the desired length of the random String to return.
* @return a random String of numbers and letters of the specified length.
*/
public static final String randomString(int length) {
if (length < 1) {
return null;
}
// Create a char buffer to put random letters and numbers in.
char [] randBuffer = new char[length];
for (int i=0; i<randBuffer.length; i++) {
randBuffer[i] = numbersAndLetters[randGen.nextInt(71)];
}
return new String(randBuffer);
}
private StringUtils() {
// Not instantiable.
}
}