/**
* Copyright (c) 2009 Juwi MacMillan Group GmbH
*
* Licensed 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
*
* 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.tizzit.util;
import java.io.PrintWriter;
/**
* Utility-Class for converting Strings to hex-format and the other way round
* @author <a href="mailto:carsten.schalm@juwimm.com">Carsten Schalm</a>
* , Juwi|MacMillan Group Gmbh, Walsrode, Germany
* @version $Id$
* @since 2.0.2
*/
public final class HexConverter {
/** maximum int value that can be converted to char */
public static final int MAX_CHAR_INT = 35;
/**
* encodes a string of 4-digit hex-numbers to unicode
* <br />
* Note: this method is slower than hexToString(String,StringBuffer)
* @param hex-string of 4-digit hex-numbers
* @return string-representation of hex-numbers
*/
public static final String hexToString(String hex) {
if (hex == null) return "";
StringBuffer result = new StringBuffer();
hexToString(hex, result);
return result.toString();
}
/**
* encodes a string of 4-digit hex-numbers to unicode
* @param hex-string of 4-digit hex-numbers
* @param out string-representation of hex-numbers
* @todo to improve performance, implement a table-lookup instead of parseInt(substring())
*/
public static final void hexToString(String hex, StringBuffer out) {
if (hex == null) return;
int length = hex.length() & -4;
for (int pos = 0; pos < length; pos += 4) {
int thisChar = 0;
try {
thisChar = Integer.parseInt(hex.substring(pos, pos + 4), 16);
} catch (NumberFormatException nfe) { /* dont care*/
}
out.append((char) thisChar);
}
}
/**
* encodes a unicode string to a string of 4-digit hex-numbers
* <br />
* Note: this method is slower than stringToHex(String,StringBuffer)
* @param java normal java string
* @return string of 4-digit hex-numbers
*/
public static final String stringToHex(String java) {
if (java == null) return "";
int length = java.length();
StringBuffer result = new StringBuffer(length * 4);
stringToHex(java, result);
return result.toString();
}
/**
* encodes a unicode string to a string of 4-digit hex-numbers
* @param java normal java string
* @param out string of 4-digit hex-numbers
* @todo to improve performance, implement a table-lookup instead of if/then cases
*/
public static final void stringToHex(String java, StringBuffer out) {
if (java == null) return;
int length = java.length();
for (int pos = 0; pos < length; pos++) {
int thisChar = (int) java.charAt(pos);
for (int digit = 0; digit < 4; digit++) {
int thisDigit = thisChar & 0xf000;
thisChar = thisChar << 4;
thisDigit = (thisDigit >> 12);
if (thisDigit >= 10)
out.append((char) (thisDigit + 87));
else
out.append((char) (thisDigit + 48));
}
}
}
/**
* encodes a unicode string to a string of 4-digit hex-numbers
* @param java normal java string
* @param out string of 4-digit hex-numbers
* @todo to improve performance, implement a table-lookup instead of if/then cases
*/
public static final void stringToHex(String java, PrintWriter out) {
if (java == null) return;
int length = java.length();
for (int pos = 0; pos < length; pos++) {
int this_char = (int) java.charAt(pos);
for (int digit = 0; digit < 4; digit++) {
int this_digit = this_char & 0xf000;
this_char = this_char << 4;
this_digit = (this_digit >> 12);
if (this_digit >= 10)
out.print((char) (this_digit + 87));
else
out.print((char) (this_digit + 48));
}
}
}
}