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// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)
package org.xbill.DNS.utils;
import java.io.*;
/**
* Routines for converting between Strings of hex-encoded data and arrays of
* binary data. This is not actually used by DNS.
*
* @author Brian Wellington
*/
public class base16 {
private static final String Base16 = "0123456789ABCDEF";
private
base16() {}
/**
* Convert binary data to a hex-encoded String
* @param b An array containing binary data
* @return A String containing the encoded data
*/
public static String
toString(byte [] b) {
ByteArrayOutputStream os = new ByteArrayOutputStream();
for (int i = 0; i < b.length; i++) {
short value = (short) (b[i] & 0xFF);
byte high = (byte) (value >> 4);
byte low = (byte) (value & 0xF);
os.write(Base16.charAt(high));
os.write(Base16.charAt(low));
}
return new String(os.toByteArray());
}
/**
* Convert a hex-encoded String to binary data
* @param str A String containing the encoded data
* @return An array containing the binary data, or null if the string is invalid
*/
public static byte []
fromString(String str) {
ByteArrayOutputStream bs = new ByteArrayOutputStream();
byte [] raw = str.getBytes();
for (int i = 0; i < raw.length; i++) {
if (!Character.isWhitespace((char)raw[i]))
bs.write(raw[i]);
}
byte [] in = bs.toByteArray();
if (in.length % 2 != 0) {
return null;
}
bs.reset();
DataOutputStream ds = new DataOutputStream(bs);
for (int i = 0; i < in.length; i += 2) {
byte high = (byte) Base16.indexOf(Character.toUpperCase((char)in[i]));
byte low = (byte) Base16.indexOf(Character.toUpperCase((char)in[i+1]));
try {
ds.writeByte((high << 4) + low);
}
catch (IOException e) {
}
}
return bs.toByteArray();
}
}
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