panda.codec.binary.Hex Maven / Gradle / Ivy
package panda.codec.binary;
import java.nio.ByteBuffer;
import java.nio.charset.Charset;
import panda.codec.BinaryDecoder;
import panda.codec.BinaryEncoder;
import panda.codec.DecoderException;
import panda.codec.EncoderException;
import panda.lang.Charsets;
import panda.lang.Strings;
/**
* Converts hexadecimal Strings. This class is thread-safe.
*/
public class Hex implements BinaryEncoder, BinaryDecoder {
/**
* Default charset name is {@link Charsets#CS_UTF_8}
*/
public static final Charset DEFAULT_CHARSET = Charsets.CS_UTF_8;
/**
* Default charset name is {@link Charsets#UTF_8}
*/
public static final String DEFAULT_CHARSET_NAME = Charsets.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 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 data An array of bytes containing hexadecimal digits
* @return A byte array containing binary data decoded from the supplied char array.
* @throws DecoderException Thrown if an odd number or illegal of bytes is supplied
*/
public static byte[] decodeHex(final String data) throws DecoderException {
return decodeHex(data.toCharArray());
}
/**
* Converts an array of 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 data An array of bytes containing hexadecimal digits
* @return A byte array containing binary data decoded from the supplied char array.
* @throws DecoderException Thrown if an odd number or illegal of bytes is supplied
*/
public static byte[] decodeHex(final char[] data) throws DecoderException {
final int len = data.length;
if ((len & 0x01) != 0) {
throw new DecoderException("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;
}
/**
* Converts an array of 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 data An array of bytes containing hexadecimal digits
* @return A byte array containing binary data decoded from the supplied char array.
* @throws DecoderException Thrown if an odd number or illegal of bytes is supplied
*/
public static String decodeHexString(final String data) throws DecoderException {
return Strings.newStringUtf8(decodeHex(data));
}
/**
* 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 a byte buffer 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 buffer to convert to Hex characters
* @return A char[] containing lower-case hexadecimal characters
*/
public static char[] encodeHex(final ByteBuffer 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
*/
public static char[] encodeHex(final byte[] data, final boolean toLowerCase) {
return encodeHex(data, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER);
}
/**
* Converts a byte buffer 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 buffer to convert to Hex characters
* @param toLowerCase true converts to lowercase, false to uppercase
* @return A char[] containing hexadecimal characters in the selected case
*/
public static char[] encodeHex(final ByteBuffer 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
*/
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 a byte buffer 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 buffer to convert to Hex characters
* @param toDigits the output alphabet (must be at least 16 characters)
* @return A char[] containing the appropriate characters from the alphabet For best results,
* this should be either upper- or lower-case hex.
*/
protected static char[] encodeHex(final ByteBuffer data, final char[] toDigits) {
return encodeHex(data.array(), toDigits);
}
/**
* 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
*/
public static String encodeHexString(final byte[] data) {
return new String(encodeHex(data));
}
/**
* 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
* @param toLowerCase true converts to lowercase, false to uppercase
* @return A String containing hexadecimal characters
*/
public static String encodeHexString(final byte[] data, final boolean toLowerCase) {
return new String(encodeHex(data, toLowerCase));
}
/**
* Converts a byte buffer 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 buffer to convert to Hex characters
* @return A String containing lower-case hexadecimal characters
*/
public static String encodeHexString(final ByteBuffer data) {
return new String(encodeHex(data));
}
/**
* Converts a byte buffer 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 buffer to convert to Hex characters
* @param toLowerCase
* true converts to lowercase, false to uppercase
* @return A String containing lower-case hexadecimal characters
*/
public static String encodeHexString(final ByteBuffer data, final boolean toLowerCase) {
return new String(encodeHex(data, toLowerCase));
}
/**
* Converts a String 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 string to convert to Hex characters
* @return A String containing hexadecimal characters
*/
public static String encodeHexString(final String data) {
return encodeHexString(Strings.getBytesUtf8(data));
}
/**
* Converts a String 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 string to convert to Hex characters
* @param toLowerCase {@code true} converts to lowercase, {@code false} to uppercase
* @return A String containing hexadecimal characters
*/
public static String encodeHexString(final String data, final boolean toLowerCase) {
return encodeHexString(Strings.getBytesUtf8(data), toLowerCase);
}
/**
* Converts a String into a String representing the hexadecimal values of each char 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 string to convert to Hex characters
* @param prefix prefix string to every code point
* @return A String containing hexadecimal characters
*/
public static String encodeHexChars(final String data, final String prefix) {
return encodeHexChars(data, prefix, true);
}
/**
* Converts a String 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 string to convert to Hex characters
* @param prefix prefix string to every code point
* @param toLowerCase {@code true} converts to lowercase, {@code false} to uppercase
* @return A String containing hexadecimal characters
*/
public static String encodeHexChars(final String data, final String prefix, final boolean toLowerCase) {
if (Strings.isEmpty(prefix)) {
return encodeHexString(data, toLowerCase);
}
char[] toDigits = toLowerCase ? DIGITS_LOWER : DIGITS_UPPER;
StringBuilder sb = new StringBuilder();
for (int i = 0; i < data.length(); i++) {
sb.append(prefix);
char c = data.charAt(i);
sb.append((char)(toDigits[(0xF000 & c) >>> 12]));
sb.append((char)(toDigits[(0xF00 & c) >>> 8]));
sb.append((char)(toDigits[(0xF0 & c) >>> 4]));
sb.append((char)(toDigits[0x0F & c]));
}
return sb.toString();
}
/**
* 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
* @throws DecoderException Thrown if ch is an illegal hex character
*/
protected static int toDigit(final char ch, final int index) throws DecoderException {
final int digit = Character.digit(ch, 16);
if (digit == -1) {
throw new DecoderException("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.
*/
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
*/
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).
* @throws DecoderException Thrown if an odd number of characters is supplied to this function
* @see #decodeHex(char[])
*/
@Override
public byte[] decode(final byte[] array) throws DecoderException {
return decodeHex(new String(array, getCharset()).toCharArray());
}
/**
* Converts a buffer 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 buffer An array of character bytes containing hexadecimal digits
* @return A byte array containing binary data decoded from the supplied byte array
* (representing characters).
* @throws DecoderException Thrown if an odd number of characters is supplied to this function
* @see #decodeHex(char[])
*/
public byte[] decode(final ByteBuffer buffer) throws DecoderException {
return decodeHex(new String(buffer.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 DecoderException Thrown if an odd number of characters is supplied to this function
* or the object is not a String or char[]
* @see #decodeHex(char[])
*/
@Override
public Object decode(final Object object) throws DecoderException {
if (object instanceof String) {
return decode(((String)object).toCharArray());
}
else if (object instanceof byte[]) {
return decode((byte[])object);
}
else if (object instanceof ByteBuffer) {
return decode((ByteBuffer)object);
}
else {
try {
return decodeHex((char[])object);
}
catch (final ClassCastException e) {
throw new DecoderException(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[])
*/
@Override
public byte[] encode(final byte[] array) {
return encodeHexString(array).getBytes(this.getCharset());
}
/**
* Converts byte buffer 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 buffer to convert to Hex characters
* @return A byte[] containing the bytes of the lower-case hexadecimal characters
* @see #encodeHex(byte[])
*/
public byte[] encode(final ByteBuffer 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 EncoderException Thrown if the given object is not a String or byte[]
* @see #encodeHex(byte[])
*/
@Override
public Object encode(final Object object) throws EncoderException {
byte[] byteArray;
if (object instanceof String) {
byteArray = ((String)object).getBytes(this.getCharset());
}
else if (object instanceof ByteBuffer) {
byteArray = ((ByteBuffer)object).array();
}
else {
try {
byteArray = (byte[])object;
}
catch (final ClassCastException e) {
throw new EncoderException(e.getMessage(), e);
}
}
return encodeHex(byteArray);
}
/**
* Gets the charset.
*
* @return the charset.
*/
public Charset getCharset() {
return this.charset;
}
/**
* Gets the charset name.
*
* @return the charset name.
*/
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.
*/
@Override
public String toString() {
return super.toString() + "[charsetName=" + this.charset + "]";
}
}