package com.clj.fastble.utils;
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public class HexUtil {
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private static final char[] DIGITS_LOWER = { '0', '1', '2', '3', '4', '5',
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'6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
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private static final char[] DIGITS_UPPER = { '0', '1', '2', '3', '4', '5',
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'6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
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public static char[] encodeHex(byte[] data) {
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return encodeHex(data, true);
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}
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public static char[] encodeHex(byte[] data, boolean toLowerCase) {
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return encodeHex(data, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER);
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}
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protected static char[] encodeHex(byte[] data, char[] toDigits) {
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if(data == null)
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return null;
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int l = data.length;
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char[] out = new char[l << 1];
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for (int i = 0, j = 0; i < l; i++) {
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out[j++] = toDigits[(0xF0 & data[i]) >>> 4];
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out[j++] = toDigits[0x0F & data[i]];
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}
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return out;
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}
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public static String encodeHexStr(byte[] data) {
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return encodeHexStr(data, true);
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}
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public static String encodeHexStr(byte[] data, boolean toLowerCase) {
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return encodeHexStr(data, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER);
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}
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protected static String encodeHexStr(byte[] data, char[] toDigits) {
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return new String(encodeHex(data, toDigits));
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}
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public static byte[] decodeHex(char[] data) {
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int len = data.length;
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if ((len & 0x01) != 0) {
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throw new RuntimeException("Odd number of characters.");
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}
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byte[] out = new byte[len >> 1];
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// two characters form the hex value.
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for (int i = 0, j = 0; j < len; i++) {
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int f = toDigit(data[j], j) << 4;
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j++;
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f = f | toDigit(data[j], j);
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j++;
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out[i] = (byte) (f & 0xFF);
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}
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return out;
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}
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protected static int toDigit(char ch, int index) {
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int digit = Character.digit(ch, 16);
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if (digit == -1) {
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throw new RuntimeException("Illegal hexadecimal character " + ch
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+ " at index " + index);
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}
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return digit;
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}
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public static byte[] hexStringToBytes(String hexString) {
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if (hexString == null || hexString.equals("")) {
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return null;
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}
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hexString = hexString.toUpperCase();
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int length = hexString.length() / 2;
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char[] hexChars = hexString.toCharArray();
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byte[] d = new byte[length];
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for (int i = 0; i < length; i++) {
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int pos = i * 2;
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d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
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}
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return d;
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}
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public static byte charToByte(char c) {
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return (byte) "0123456789ABCDEF".indexOf(c);
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}
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public static String extractData(byte[] data, int position) {
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return HexUtil.encodeHexStr(new byte[]{data[position]});
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}
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}
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