package com.hwlcn.security.codec;
public class Hex {
private static final char[] DIGITS = {
'0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
};
public static String encodeToString(byte[] bytes) {
char[] encodedChars = encode(bytes);
return new String(encodedChars);
}
public static char[] encode(byte[] data) {
int l = data.length;
char[] out = new char[l << 1];
for (int i = 0, j = 0; i < l; i++) {
out[j++] = DIGITS[(0xF0 & data[i]) >>> 4];
out[j++] = DIGITS[0x0F & data[i]];
}
return out;
}
public static byte[] decode(byte[] array) throws IllegalArgumentException {
String s = CodecSupport.toString(array);
return decode(s);
}
public static byte[] decode(String hex) {
return decode(hex.toCharArray());
}
public static byte[] decode(char[] data) throws IllegalArgumentException {
int len = data.length;
if ((len & 0x01) != 0) {
throw new IllegalArgumentException("Odd number of characters.");
}
byte[] out = new byte[len >> 1];
for (int i = 0, j = 0; j < len; i++) {
int f = toDigit(data[j], j) << 4;
j++;
f = f | toDigit(data[j], j);
j++;
out[i] = (byte) (f & 0xFF);
}
return out;
}
protected static int toDigit(char ch, int index) throws IllegalArgumentException {
int digit = Character.digit(ch, 16);
if (digit == -1) {
throw new IllegalArgumentException("Illegal hexadecimal charcter " + ch + " at index " + index);
}
return digit;
}
}