org.beykery.util.bip44.HexUtils Maven / Gradle / Ivy
/*
* Copyright 2013, 2014 Megion Research & Development 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.beykery.util.bip44;
/**
* Utilities for going to and from ASCII-HEX representation.
*/
public class HexUtils {
/**
* Encodes an array of bytes as hex symbols.
*
* @param bytes
* the array of bytes to encode
* @return the resulting hex string
*/
public static String toHex(byte[] bytes) {
return toHex(bytes, null);
}
/**
* Encodes an array of bytes as hex symbols.
*
* @param bytes
* the array of bytes to encode
* @param separator
* the separator to use between two bytes, can be null
* @return the resulting hex string
*/
public static String toHex(byte[] bytes, String separator) {
return toHex(bytes, 0, bytes.length, separator);
}
/**
* Encodes an array of bytes as hex symbols.
*
* @param bytes
* the array of bytes to encode
* @param offset
* the start offset in the array of bytes
* @param length
* the number of bytes to encode
* @return the resulting hex string
*/
public static String toHex(byte[] bytes, int offset, int length) {
return toHex(bytes, offset, length, null);
}
/**
* Encodes a single byte to hex symbols.
*
* @param b the byte to encode
* @return the resulting hex string
*/
public static String toHex(byte b) {
StringBuilder sb = new StringBuilder();
appendByteAsHex(sb, b);
return sb.toString();
}
/**
* Encodes an array of bytes as hex symbols.
*
* @param bytes
* the array of bytes to encode
* @param offset
* the start offset in the array of bytes
* @param length
* the number of bytes to encode
* @param separator
* the separator to use between two bytes, can be null
* @return the resulting hex string
*/
public static String toHex(byte[] bytes, int offset, int length, String separator) {
StringBuffer result = new StringBuffer();
for (int i = 0; i < length; i++) {
int unsignedByte = bytes[i + offset] & 0xff;
if (unsignedByte < 16) {
result.append("0");
}
result.append(Integer.toHexString(unsignedByte));
if (separator != null && i + 1 < length) {
result.append(separator);
}
}
return result.toString();
}
/**
* Get the byte representation of an ASCII-HEX string.
*
* @param hexString
* The string to convert to bytes
* @return The byte representation of the ASCII-HEX string.
*/
public static byte[] toBytes(String hexString) {
if (hexString == null || hexString.length() % 2 != 0) {
throw new RuntimeException("Input string must contain an even number of characters");
}
char[] hex = hexString.toCharArray();
int length = hex.length / 2;
byte[] raw = new byte[length];
for (int i = 0; i < length; i++) {
int high = Character.digit(hex[i * 2], 16);
int low = Character.digit(hex[i * 2 + 1], 16);
if (high < 0 || low < 0){
throw new RuntimeException("Invalid hex digit " + hex[i * 2] + hex[i * 2 + 1]);
}
int value = (high << 4) | low;
if (value > 127)
value -= 256;
raw[i] = (byte) value;
}
return raw;
}
public static void appendByteAsHex(StringBuilder sb, byte b) {
int unsignedByte = b & 0xFF;
if (unsignedByte < 16) {
sb.append("0");
}
sb.append(Integer.toHexString(unsignedByte));
}
public static boolean isAllZero(byte[] bytes){
for (byte b : bytes){
if (b != 0) {
return false;
}
}
return true;
}
}