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Awake FILE is a secure Open Source framework that allows to program very easily file uploads/downloads and RPC through http. File transfers include powerful features like file chunking and automatic recovery mechanism. Security has been taken into account from the design: server side allows to specify strong security rules in order to protect the files and to secure the RPC calls.

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/*
 * This file is part of Awake FILE. 
 * Awake FILE: Easy file upload & download over HTTP with Java.                                    
 * Copyright (C) 2014,  KawanSoft SAS
 * (http://www.kawansoft.com). All rights reserved.                                
 *                                                                               
 * Awake FILE is free software; you can redistribute it and/or                 
 * modify it under the terms of the GNU Lesser General Public                    
 * License as published by the Free Software Foundation; either                  
 * version 2.1 of the License, or (at your option) any later version.            
 *                                                                               
 * Awake FILE is distributed in the hope that it will be useful,               
 * but WITHOUT ANY WARRANTY; without even the implied warranty of                
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU             
 * Lesser General Public License for more details.                               
 *                                                                               
 * You should have received a copy of the GNU Lesser General Public              
 * License along with this library; if not, write to the Free Software           
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  
 * 02110-1301  USA
 *
 * Any modifications to this file must keep this entire header
 * intact.
 */
package org.awakefw.commons.codec.binary;

import java.io.UnsupportedEncodingException;

import org.awakefw.commons.codec.BinaryDecoder;
import org.awakefw.commons.codec.BinaryEncoder;
import org.awakefw.commons.codec.CharEncoding;
import org.awakefw.commons.codec.DecoderException;
import org.awakefw.commons.codec.EncoderException;

/**
 * Hex encoder and decoder. The charset used for certain operation can be set, the default is set in
 * {@link #DEFAULT_CHARSET_NAME}
 * 
 * @since 1.1
 * @author Apache Software Foundation
 * @version $Id: Hex.java 801639 2009-08-06 13:15:10Z niallp $
 */
public class AwakeHex implements BinaryEncoder, BinaryDecoder {

    /**
     * Default charset name is {@link CharEncoding#UTF_8}
     */
    public static final String DEFAULT_CHARSET_NAME = CharEncoding.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 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 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(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(byte[] data, 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(byte[] data, char[] toDigits) {
        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++] = 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(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
     * @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;
    }

    private final String charsetName;

    /**
     * Creates a new codec with the default charset name {@link #DEFAULT_CHARSET_NAME}
     */
    public AwakeHex() {
        // use default encoding
        this.charsetName = DEFAULT_CHARSET_NAME;
    }

    /**
     * Creates a new codec with the given charset name.
     * 
     * @param csName
     *            the charset name.
     * @since 1.4
     */
    public AwakeHex(String csName) {
        this.charsetName = csName;
    }

    /**
     * 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[])
     */
    public byte[] decode(byte[] array) throws DecoderException {
        try {
            return decodeHex(new String(array, getCharsetName()).toCharArray());
        } catch (UnsupportedEncodingException e) {
            throw new DecoderException(e.getMessage(), e);
        }
    }

    /**
     * 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[])
     */
    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(), 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 #getCharsetName()}. *

* * @param array * a byte[] to convert to Hex characters * @return A byte[] containing the bytes of the hexadecimal characters * @throws IllegalStateException * if the charsetName is invalid. This API throws {@link IllegalStateException} instead of * {@link UnsupportedEncodingException} for backward compatibility. * @see #encodeHex(byte[]) */ public byte[] encode(byte[] array) { return AwakeStringUtils.getBytesUnchecked(encodeHexString(array), getCharsetName()); } /** * 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 #getCharsetName()}. *

* * @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[]) */ public Object encode(Object object) throws EncoderException { try { byte[] byteArray = object instanceof String ? ((String) object).getBytes(getCharsetName()) : (byte[]) object; return encodeHex(byteArray); } catch (ClassCastException e) { throw new EncoderException(e.getMessage(), e); } catch (UnsupportedEncodingException e) { throw new EncoderException(e.getMessage(), e); } } /** * Gets the charset name. * * @return the charset name. * @since 1.4 */ public String getCharsetName() { return this.charsetName; } /** * 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.charsetName + "]"; } }




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