com.aeontronix.commons.Hex Maven / Gradle / Ivy
/*
* Copyright (c) 2014 Kloudtek Ltd
*/
package com.aeontronix.commons;
/**
* Created by yannick on 25/08/2014.
*/
import java.nio.charset.Charset;
public class Hex {
/**
* Default charset (UTF-8)
*
* @since 1.4
*/
public static final String DEFAULT_CHARSET_NAME = "UTF-8";
/**
* Default charset name (UTF-8)
*
* @since 1.7
*/
public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
/**
* Used to build output as Hex
*/
private static final char[] DIGITS_LOWER =
{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
/**
* Used to build output as Hex
*/
private static final char[] DIGITS_UPPER =
{'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
/**
* Converts an array of characters representing hexadecimal values into an array of bytes of those same values. The
* returned array will be half the length of the passed array, as it takes two characters to represent any given
* byte. An exception is thrown if the passed char array has an odd number of elements.
*
* @param data An array of characters containing hexadecimal digits
* @return A byte array containing binary data decoded from the supplied char array.
* @throws IllegalArgumentException Thrown if an odd number or illegal of characters is supplied
*/
public static byte[] decodeHex(final char[] data) throws IllegalArgumentException {
final int len = data.length;
if ((len & 0x01) != 0) {
throw new IllegalArgumentException("Odd number of characters.");
}
final byte[] out = new byte[len >> 1];
// two characters form the hex value.
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;
}
public static byte[] decodeHex(String data) {
return decodeHex(data.toCharArray());
}
/**
* Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
* The returned array will be double the length of the passed array, as it takes two characters to represent any
* given byte.
*
* @param data a byte[] to convert to Hex characters
* @return A char[] containing hexadecimal characters
*/
public static char[] encodeHex(final byte[] data) {
return encodeHex(data, true);
}
/**
* Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
* The returned array will be double the length of the passed array, as it takes two characters to represent any
* given byte.
*
* @param data a byte[] to convert to Hex characters
* @param toLowerCase true converts to lowercase, false to uppercase
* @return A char[] containing hexadecimal characters
* @since 1.4
*/
public static char[] encodeHex(final byte[] data, final boolean toLowerCase) {
return encodeHex(data, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER);
}
/**
* Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
* The returned array will be double the length of the passed array, as it takes two characters to represent any
* given byte.
*
* @param data a byte[] to convert to Hex characters
* @param toDigits the output alphabet
* @return A char[] containing hexadecimal characters
* @since 1.4
*/
protected static char[] encodeHex(final byte[] data, final char[] toDigits) {
final int l = data.length;
final char[] out = new char[l << 1];
// two characters form the hex value.
for (int i = 0, j = 0; i < l; i++) {
out[j++] = toDigits[(0xF0 & data[i]) >>> 4];
out[j++] = toDigits[0x0F & data[i]];
}
return out;
}
/**
* Converts an array of bytes into a String representing the hexadecimal values of each byte in order. The returned
* String will be double the length of the passed array, as it takes two characters to represent any given byte.
*
* @param data a byte[] to convert to Hex characters
* @return A String containing hexadecimal characters
* @since 1.4
*/
public static String encodeHexString(final byte[] data) {
return new String(encodeHex(data));
}
/**
* Converts a hexadecimal character to an integer.
*
* @param ch A character to convert to an integer digit
* @param index The index of the character in the source
* @return An integer
*/
protected static int toDigit(final char ch, final int index) throws IllegalArgumentException {
final int digit = Character.digit(ch, 16);
if (digit == -1) {
throw new IllegalArgumentException("Illegal hexadecimal character " + ch + " at index " + index);
}
return digit;
}
private final Charset charset;
/**
* Creates a new codec with the default charset name {@link #DEFAULT_CHARSET}
*/
public Hex() {
// use default encoding
this.charset = DEFAULT_CHARSET;
}
/**
* Creates a new codec with the given Charset.
*
* @param charset the charset.
* @since 1.7
*/
public Hex(final Charset charset) {
this.charset = charset;
}
/**
* Creates a new codec with the given charset name.
*
* @param charsetName the charset name.
* @throws java.nio.charset.UnsupportedCharsetException If the named charset is unavailable
* @since 1.7 throws UnsupportedCharsetException if the named charset is unavailable
*/
public Hex(final String charsetName) {
this(Charset.forName(charsetName));
}
/**
* Converts an array of character bytes representing hexadecimal values into an array of bytes of those same values.
* The returned array will be half the length of the passed array, as it takes two characters to represent any given
* byte. An exception is thrown if the passed char array has an odd number of elements.
*
* @param array An array of character bytes containing hexadecimal digits
* @return A byte array containing binary data decoded from the supplied byte array (representing characters).
* @see #decodeHex(char[])
*/
public byte[] decode(final byte[] array) throws IllegalArgumentException {
return decodeHex(new String(array, getCharset()).toCharArray());
}
/**
* Converts a String or an array of character bytes representing hexadecimal values into an array of bytes of those
* same values. The returned array will be half the length of the passed String or array, as it takes two characters
* to represent any given byte. An exception is thrown if the passed char array has an odd number of elements.
*
* @param object A String or, an array of character bytes containing hexadecimal digits
* @return A byte array containing binary data decoded from the supplied byte array (representing characters).
* @throws IllegalArgumentException Thrown if an odd number of characters is supplied to this function or the object is not a String or
* char[]
* @see #decodeHex(char[])
*/
public Object decode(final Object object) throws IllegalArgumentException {
try {
final char[] charArray = object instanceof String ? ((String) object).toCharArray() : (char[]) object;
return decodeHex(charArray);
} catch (final ClassCastException e) {
throw new IllegalArgumentException(e.getMessage(), e);
}
}
/**
* Converts an array of bytes into an array of bytes for the characters representing the hexadecimal values of each
* byte in order. The returned array will be double the length of the passed array, as it takes two characters to
* represent any given byte.
*
* The conversion from hexadecimal characters to the returned bytes is performed with the charset named by
* {@link #getCharset()}.
*
*
* @param array a byte[] to convert to Hex characters
* @return A byte[] containing the bytes of the hexadecimal characters
* @see #encodeHex(byte[])
* @since 1.7 No longer throws IllegalStateException if the charsetName is invalid.
*/
public byte[] encode(final byte[] array) {
return encodeHexString(array).getBytes(this.getCharset());
}
/**
* Converts a String or an array of bytes into an array of characters representing the hexadecimal values of each
* byte in order. The returned array will be double the length of the passed String or array, as it takes two
* characters to represent any given byte.
*
* The conversion from hexadecimal characters to bytes to be encoded to performed with the charset named by
* {@link #getCharset()}.
*
*
* @param object a String, or byte[] to convert to Hex characters
* @return A char[] containing hexadecimal characters
* @throws IllegalArgumentException Thrown if the given object is not a String or byte[]
* @see #encodeHex(byte[])
*/
public Object encode(final Object object) throws IllegalArgumentException {
try {
final byte[] byteArray = object instanceof String ?
((String) object).getBytes(this.getCharset()) : (byte[]) object;
return encodeHex(byteArray);
} catch (final ClassCastException e) {
throw new IllegalArgumentException(e.getMessage(), e);
}
}
/**
* Gets the charset.
*
* @return the charset.
* @since 1.7
*/
public Charset getCharset() {
return this.charset;
}
/**
* Gets the charset name.
*
* @return the charset name.
* @since 1.4
*/
public String getCharsetName() {
return this.charset.name();
}
/**
* Returns a string representation of the object, which includes the charset name.
*
* @return a string representation of the object.
*/
public String toString() {
return super.toString() + "[charsetName=" + this.charset + "]";
}
}
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