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/*-
* ============LICENSE_START=======================================================
* openECOMP : APP-C
* ================================================================================
* Copyright (C) 2017 AT&T Intellectual Property. All rights
* reserved.
* ================================================================================
* 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.
* ============LICENSE_END=========================================================
*/
package org.openecomp.appc.encryption;
import java.util.HashMap;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* HexHelper utility used for encryption/decryption
*/
public final class HexHelper {
@SuppressWarnings({
"javadoc", "nls"
})
public static final String CM_PATH = "@(#) [viewpath]/[item]";
@SuppressWarnings({
"nls", "javadoc"
})
public static final String CM_PROJECT = "@(#) [environment] [baseline]";
@SuppressWarnings({
"javadoc", "nls"
})
public static final String CM_VERSION = "@(#) [version] [crtime]";
private static final char[] HEX_TABLE = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D',
'E', 'F' };
/**
* The logger for this class.
*/
private static final Logger LOG = LoggerFactory.getLogger(HexHelper.class);
private static Map<Character, Integer> TextToHex;
static {
TextToHex = new HashMap<>();
TextToHex.put(Character.valueOf('0'), Integer.valueOf(0));
TextToHex.put(Character.valueOf('1'), Integer.valueOf(1));
TextToHex.put(Character.valueOf('2'), Integer.valueOf(2));
TextToHex.put(Character.valueOf('3'), Integer.valueOf(3));
TextToHex.put(Character.valueOf('4'), Integer.valueOf(4));
TextToHex.put(Character.valueOf('5'), Integer.valueOf(5));
TextToHex.put(Character.valueOf('6'), Integer.valueOf(6));
TextToHex.put(Character.valueOf('7'), Integer.valueOf(7));
TextToHex.put(Character.valueOf('8'), Integer.valueOf(8));
TextToHex.put(Character.valueOf('9'), Integer.valueOf(9));
TextToHex.put(Character.valueOf('A'), Integer.valueOf(10));
TextToHex.put(Character.valueOf('B'), Integer.valueOf(11));
TextToHex.put(Character.valueOf('C'), Integer.valueOf(12));
TextToHex.put(Character.valueOf('D'), Integer.valueOf(13));
TextToHex.put(Character.valueOf('E'), Integer.valueOf(14));
TextToHex.put(Character.valueOf('F'), Integer.valueOf(15));
}
/**
* Default private constructor prevents instantiation
*/
private HexHelper() {
// no-op
}
/**
* Converts an array of bytes to the equivalent string representation using hexadecimal notation and returning that
* representation in a StringBuffer.
*
* @param bytes
* The bytes to be converted to a hexadecimal string
* @return The string representation
*/
public static StringBuffer convertBytesToHexSB(byte[] bytes) {
StringBuffer sb = new StringBuffer(bytes.length * 2);
int byteLen = bytes.length;
for (int index = 0; index < byteLen; index++) {
char tempChar;
// Get the first 4 bits (high) Do bitwise logical AND to get rid of
// low nibble. Shift results to right by 4 and get char
// representation
tempChar = HEX_TABLE[((bytes[index] & 0xf0) >>> 4)];
sb.append(tempChar);
// Get the last 4 bits (low) Do bitwise logical AND to get rid of
// high nibble. Get char representation
tempChar = HEX_TABLE[(bytes[index] & 0x0f)];
sb.append(tempChar);
}
return sb;
}
/**
* Converts a hexadecimal string representation of a binary value to an array of bytes
*
* @param hexValue
* The hex representation string to be converted
* @return The array of bytes that contains the binary value
*/
@SuppressWarnings("nls")
public static byte[] convertHexToBytes(String hexValue) {
byte[] bytes = null;
byte high;
byte low;
char hexChar;
StringBuffer buffer = new StringBuffer(hexValue.toUpperCase());
if (buffer.length() % 2 != 0) {
LOG.warn("Invalid HEX value length. "
+ "The length of the value has to be a multiple of 2. Prepending '0' value.");
buffer.insert(0, '0');
}
int hexLength = buffer.length();
int byteLength = hexLength / 2;
bytes = new byte[byteLength];
for (int index = 0; index < hexLength; index += 2) {
hexChar = buffer.charAt(index);
high = (TextToHex.get(Character.valueOf(hexChar))).byteValue();
high = (byte) (high << 4);
hexChar = buffer.charAt(index + 1);
low = (TextToHex.get(Character.valueOf(hexChar))).byteValue();
high = (byte) (high | low);
bytes[index / 2] = high;
}
return bytes;
}
}
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