cn.felord.utils.Hex Maven / Gradle / Ivy
/*
* Copyright (c) 2023. felord.cn
* 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
* https://www.apache.org/licenses/LICENSE-2.0
* Website:
* https://felord.cn
* 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 cn.felord.utils;
import java.nio.ByteBuffer;
/**
* Converts hexadecimal Strings.
*
* This class is thread-safe.
*
* @since 1.1
*/
public class Hex {
/**
* 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 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 lower-case 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 {@code true} converts to lowercase, {@code false} to uppercase
* @return A char[] containing hexadecimal characters in the selected case
* @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 (must contain at least 16 chars)
* @return A char[] containing the appropriate characters from the alphabet For best results, this should be either upper- or lower-case hex.
* @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];
encodeHex(data, 0, data.length, toDigits, out, 0);
return out;
}
/**
* Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
*
* @param data a byte[] to convert to hex characters
* @param dataOffset the position in {@code data} to start encoding from
* @param dataLen the number of bytes from {@code dataOffset} to encode
* @param toLowerCase {@code true} converts to lowercase, {@code false} to uppercase
* @return A char[] containing the appropriate characters from the alphabet For best results, this should be either upper- or lower-case hex.
* @since 1.15
*/
public static char[] encodeHex(final byte[] data, final int dataOffset, final int dataLen,
final boolean toLowerCase) {
final char[] out = new char[dataLen << 1];
encodeHex(data, dataOffset, dataLen, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER, out, 0);
return out;
}
/**
* Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
*
* @param data a byte[] to convert to hex characters
* @param dataOffset the position in {@code data} to start encoding from
* @param dataLen the number of bytes from {@code dataOffset} to encode
* @param toLowerCase {@code true} converts to lowercase, {@code false} to uppercase
* @param out a char[] which will hold the resultant appropriate characters from the alphabet.
* @param outOffset the position within {@code out} at which to start writing the encoded characters.
* @since 1.15
*/
public static void encodeHex(final byte[] data, final int dataOffset, final int dataLen,
final boolean toLowerCase, final char[] out, final int outOffset) {
encodeHex(data, dataOffset, dataLen, toLowerCase ? DIGITS_LOWER : DIGITS_UPPER, out, outOffset);
}
/**
* Converts an array of bytes into an array of characters representing the hexadecimal values of each byte in order.
*
* @param data a byte[] to convert to hex characters
* @param dataOffset the position in {@code data} to start encoding from
* @param dataLen the number of bytes from {@code dataOffset} to encode
* @param toDigits the output alphabet (must contain at least 16 chars)
* @param out a char[] which will hold the resultant appropriate characters from the alphabet.
* @param outOffset the position within {@code out} at which to start writing the encoded characters.
*/
private static void encodeHex(final byte[] data, final int dataOffset, final int dataLen, final char[] toDigits,
final char[] out, final int outOffset) {
// two characters form the hex value.
for (int i = dataOffset, j = outOffset; i < dataOffset + dataLen; i++) {
out[j++] = toDigits[(0xF0 & data[i]) >>> 4];
out[j++] = toDigits[0x0F & data[i]];
}
}
/**
* 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.
*
*
All bytes identified by {@link ByteBuffer#remaining()} will be used; after this method
* the value {@link ByteBuffer#remaining() remaining()} will be zero.
*
* @param data a byte buffer to convert to hex characters
* @return A char[] containing lower-case hexadecimal characters
* @since 1.11
*/
public static char[] encodeHex(final ByteBuffer 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.
*
* All bytes identified by {@link ByteBuffer#remaining()} will be used; after this method
* the value {@link ByteBuffer#remaining() remaining()} will be zero.
*
* @param data a byte buffer to convert to hex characters
* @param toLowerCase {@code true} converts to lowercase, {@code false} to uppercase
* @return A char[] containing hexadecimal characters in the selected case
* @since 1.11
*/
public static char[] encodeHex(final ByteBuffer 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.
*
* All bytes identified by {@link ByteBuffer#remaining()} will be used; after this method
* the value {@link ByteBuffer#remaining() remaining()} will be zero.
*
* @param byteBuffer 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.
* @since 1.11
*/
protected static char[] encodeHex(final ByteBuffer byteBuffer, final char[] toDigits) {
return encodeHex(toByteArray(byteBuffer), 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 lower-case hexadecimal characters
* @since 1.4
*/
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 {@code true} converts to lowercase, {@code false} to uppercase
* @return A String containing lower-case hexadecimal characters
* @since 1.11
*/
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.
*
* All bytes identified by {@link ByteBuffer#remaining()} will be used; after this method
* the value {@link ByteBuffer#remaining() remaining()} will be zero.
*
* @param data a byte buffer to convert to hex characters
* @return A String containing lower-case hexadecimal characters
* @since 1.11
*/
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.
*
* All bytes identified by {@link ByteBuffer#remaining()} will be used; after this method
* the value {@link ByteBuffer#remaining() remaining()} will be zero.
*
* @param data a byte buffer to convert to hex characters
* @param toLowerCase {@code true} converts to lowercase, {@code false} to uppercase
* @return A String containing lower-case hexadecimal characters
* @since 1.11
*/
public static String encodeHexString(final ByteBuffer data, final boolean toLowerCase) {
return new String(encodeHex(data, toLowerCase));
}
/**
* Convert the byte buffer to a byte array. All bytes identified by
* {@link ByteBuffer#remaining()} will be used.
*
* @param byteBuffer the byte buffer
* @return the byte[]
*/
private static byte[] toByteArray(final ByteBuffer byteBuffer) {
final int remaining = byteBuffer.remaining();
// Use the underlying buffer if possible
if (byteBuffer.hasArray()) {
final byte[] byteArray = byteBuffer.array();
if (remaining == byteArray.length) {
byteBuffer.position(remaining);
return byteArray;
}
}
// Copy the bytes
final byte[] byteArray = new byte[remaining];
byteBuffer.get(byteArray);
return byteArray;
}
}