| /* |
| * Copyright 2001-2004 The Apache Software Foundation. |
| * |
| * 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 |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * 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 org.apache.commons.codec.binary; |
| |
| import org.apache.commons.codec.BinaryDecoder; |
| import org.apache.commons.codec.BinaryEncoder; |
| import org.apache.commons.codec.DecoderException; |
| import org.apache.commons.codec.EncoderException; |
| |
| /** |
| * Hex encoder and decoder. |
| * |
| * @since 1.1 |
| * @author Apache Software Foundation |
| * @version $Id: Hex.java,v 1.13 2004/04/18 18:22:33 ggregory Exp $ |
| */ |
| public class Hex implements BinaryEncoder, BinaryDecoder { |
| |
| /** |
| * Used building output as Hex |
| */ |
| private static final char[] DIGITS = { |
| '0', '1', '2', '3', '4', '5', '6', '7', |
| '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' |
| }; |
| |
| /** |
| * Converts an array of characters representing hexidecimal 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 hexidecimal digits |
| * @return A byte array containing binary data decoded from |
| * the supplied char array. |
| * @throws DecoderException Thrown if an odd number or illegal of characters |
| * is supplied |
| */ |
| public static byte[] decodeHex(char[] data) throws DecoderException { |
| |
| int len = data.length; |
| |
| if ((len & 0x01) != 0) { |
| throw new DecoderException("Odd number of characters."); |
| } |
| |
| 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 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(char ch, int index) throws DecoderException { |
| int digit = Character.digit(ch, 16); |
| if (digit == -1) { |
| throw new DecoderException("Illegal hexadecimal charcter " + ch + " at index " + index); |
| } |
| return digit; |
| } |
| |
| /** |
| * Converts an array of bytes into an array of characters representing the hexidecimal 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 hexidecimal characters |
| */ |
| public static char[] encodeHex(byte[] data) { |
| |
| int l = data.length; |
| |
| char[] out = new char[l << 1]; |
| |
| // two characters form the hex value. |
| for (int i = 0, j = 0; i < l; i++) { |
| out[j++] = DIGITS[(0xF0 & data[i]) >>> 4 ]; |
| out[j++] = DIGITS[ 0x0F & data[i] ]; |
| } |
| |
| return out; |
| } |
| |
| /** |
| * Converts an array of character bytes representing hexidecimal 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 hexidecimal 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(byte[] array) throws DecoderException { |
| return decodeHex(new String(array).toCharArray()); |
| } |
| |
| /** |
| * Converts a String or an array of character bytes representing hexidecimal 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 hexidecimal 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[]) |
| */ |
| public Object decode(Object object) throws DecoderException { |
| try { |
| char[] charArray = object instanceof String ? ((String) object).toCharArray() : (char[]) object; |
| return decodeHex(charArray); |
| } catch (ClassCastException e) { |
| throw new DecoderException(e.getMessage()); |
| } |
| } |
| |
| /** |
| * Converts an array of bytes into an array of bytes for the characters representing the |
| * hexidecimal 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 array a byte[] to convert to Hex characters |
| * @return A byte[] containing the bytes of the hexidecimal characters |
| * @see #encodeHex(byte[]) |
| */ |
| public byte[] encode(byte[] array) { |
| return new String(encodeHex(array)).getBytes(); |
| } |
| |
| /** |
| * Converts a String or an array of bytes into an array of characters representing the |
| * hexidecimal 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. |
| * |
| * @param object a String, or byte[] to convert to Hex characters |
| * @return A char[] containing hexidecimal characters |
| * @throws EncoderException Thrown if the given object is not a String or byte[] |
| * @see #encodeHex(byte[]) |
| */ |
| public Object encode(Object object) throws EncoderException { |
| try { |
| byte[] byteArray = object instanceof String ? ((String) object).getBytes() : (byte[]) object; |
| return encodeHex(byteArray); |
| } catch (ClassCastException e) { |
| throw new EncoderException(e.getMessage()); |
| } |
| } |
| |
| } |
| |