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/*
* 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 org.apache.tomcat.util.res.StringManager;
/**
* Tables useful when 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 {
private static final StringManager sm = StringManager.getManager(HexUtils.class);
// -------------------------------------------------------------- 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.
*/
private 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' };
/**
* Table for byte to hex string translation.
*/
private static final char[] hex = "0123456789abcdef".toCharArray();
// --------------------------------------------------------- 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;
}
}
public static byte getHex(int index) {
return HEX[index];
}
public static String toHexString(char c) {
// 2 bytes / 4 hex digits
StringBuilder sb = new StringBuilder(4);
sb.append(hex[(c & 0xf000) >> 12]);
sb.append(hex[(c & 0x0f00) >> 8]);
sb.append(hex[(c & 0xf0) >> 4]);
sb.append(hex[(c & 0x0f)]);
return sb.toString();
}
public static String toHexString(byte[] bytes) {
if (null == bytes) {
return null;
}
StringBuilder sb = new StringBuilder(bytes.length << 1);
for (byte aByte : bytes) {
sb.append(hex[(aByte & 0xf0) >> 4])
.append(hex[(aByte & 0x0f)])
;
}
return sb.toString();
}
public static byte[] fromHexString(String input) {
if (input == null) {
return null;
}
if ((input.length() & 1) == 1) {
// Odd number of characters
throw new IllegalArgumentException(sm.getString("hexUtils.fromHex.oddDigits"));
}
char[] inputChars = input.toCharArray();
byte[] result = new byte[input.length() >> 1];
for (int i = 0; i < result.length; i++) {
int upperNibble = getDec(inputChars[2*i]);
int lowerNibble = getDec(inputChars[2*i + 1]);
if (upperNibble < 0 || lowerNibble < 0) {
// Non hex character
throw new IllegalArgumentException(sm.getString("hexUtils.fromHex.nonHex"));
}
result[i] = (byte) ((upperNibble << 4) + lowerNibble);
}
return result;
}
}
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