/*
* 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
*
* 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.tomcat.util.buf;
import java.io.ByteArrayOutputStream;
import org.apache.tomcat.util.res.StringManager;
/**
* Library of utility methods useful in dealing with converting byte arrays
* to and from strings of hexadecimal digits.
* Code from Ajp11, from Apache's JServ.
*
* @author Craig R. McClanahan
*/
public final class HexUtils {
// -------------------------------------------------------------- Constants
/**
* Table for HEX to DEC byte translation.
*/
private static final int[] DEC = {
00, 01, 02, 03, 04, 05, 06, 07, 8, 9, -1, -1, -1, -1, -1, -1,
-1, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, 10, 11, 12, 13, 14, 15,
};
/**
* Table for DEC to HEX byte translation.
*/
public static final byte[] HEX =
{ (byte) '0', (byte) '1', (byte) '2', (byte) '3', (byte) '4', (byte) '5',
(byte) '6', (byte) '7', (byte) '8', (byte) '9', (byte) 'a', (byte) 'b',
(byte) 'c', (byte) 'd', (byte) 'e', (byte) 'f' };
/**
* The string manager for this package.
*/
private static StringManager sm =
StringManager.getManager("org.apache.tomcat.util.buf.res");
// --------------------------------------------------------- Static Methods
public static int getDec(int index){
// Fast for correct values, slower for incorrect ones
try {
return DEC[index - '0'];
} catch (ArrayIndexOutOfBoundsException ex) {
return -1;
}
}
/**
* Convert a String of hexadecimal digits into the corresponding
* byte array by encoding each two hexadecimal digits as a byte.
*
* @param digits Hexadecimal digits representation
*
* @exception IllegalArgumentException if an invalid hexadecimal digit
* is found, or the input string contains an odd number of hexadecimal
* digits
*/
public static byte[] convert(String digits) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
for (int i = 0; i < digits.length(); i += 2) {
char c1 = digits.charAt(i);
if ((i+1) >= digits.length())
throw new IllegalArgumentException
(sm.getString("hexUtil.odd"));
char c2 = digits.charAt(i + 1);
byte b = 0;
if ((c1 >= '0') && (c1 <= '9'))
b += ((c1 - '0') * 16);
else if ((c1 >= 'a') && (c1 <= 'f'))
b += ((c1 - 'a' + 10) * 16);
else if ((c1 >= 'A') && (c1 <= 'F'))
b += ((c1 - 'A' + 10) * 16);
else
throw new IllegalArgumentException
(sm.getString("hexUtil.bad"));
if ((c2 >= '0') && (c2 <= '9'))
b += (c2 - '0');
else if ((c2 >= 'a') && (c2 <= 'f'))
b += (c2 - 'a' + 10);
else if ((c2 >= 'A') && (c2 <= 'F'))
b += (c2 - 'A' + 10);
else
throw new IllegalArgumentException
(sm.getString("hexUtil.bad"));
baos.write(b);
}
return (baos.toByteArray());
}
/**
* Convert a byte array into a printable format containing a
* String of hexadecimal digit characters (two per byte).
*
* @param bytes Byte array representation
*/
public static String convert(byte bytes[]) {
StringBuffer sb = new StringBuffer(bytes.length * 2);
for (int i = 0; i < bytes.length; i++) {
sb.append(convertDigit((int) (bytes[i] >> 4)));
sb.append(convertDigit((int) (bytes[i] & 0x0f)));
}
return (sb.toString());
}
/**
* Convert 4 hex digits to an int, and return the number of converted
* bytes.
*
* @param hex Byte array containing exactly four hexadecimal digits
*
* @exception IllegalArgumentException if an invalid hexadecimal digit
* is included
* @deprecated Not used, will be removed in Tomcat 7
*/
public static int convert2Int( byte[] hex ) {
// Code from Ajp11, from Apache's JServ
// assert b.length==4
// assert valid data
int len;
if(hex.length < 4 ) return 0;
if( getDec(hex[0])<0 )
throw new IllegalArgumentException(sm.getString("hexUtil.bad"));
len = getDec(hex[0]);
len = len << 4;
if( getDec(hex[1])<0 )
throw new IllegalArgumentException(sm.getString("hexUtil.bad"));
len += getDec(hex[1]);
len = len << 4;
if( getDec(hex[2])<0 )
throw new IllegalArgumentException(sm.getString("hexUtil.bad"));
len += getDec(hex[2]);
len = len << 4;
if( getDec(hex[3])<0 )
throw new IllegalArgumentException(sm.getString("hexUtil.bad"));
len += getDec(hex[3]);
return len;
}
/**
* [Private] Convert the specified value (0 .. 15) to the corresponding
* hexadecimal digit.
*
* @param value Value to be converted
*/
private static char convertDigit(int value) {
value &= 0x0f;
if (value >= 10)
return ((char) (value - 10 + 'a'));
else
return ((char) (value + '0'));
}
}