base64.java

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	 * no guarantee as to which one will be picked.
	 */
	private final static byte[] getAlphabet( int options )
	{
		if( (options & URL_SAFE) == URL_SAFE ) return _URL_SAFE_ALPHABET;
		else if( (options & ORDERED) == ORDERED ) return _ORDERED_ALPHABET;
		else return _STANDARD_ALPHABET;

	}	// end getAlphabet


	/**
	 * Returns one of the _SOMETHING_DECODABET byte arrays depending on
	 * the options specified.
	 * It's possible, though silly, to specify ORDERED and URL_SAFE
	 * in which case one of them will be picked, though there is
	 * no guarantee as to which one will be picked.
	 */
	private final static byte[] getDecodabet( int options )
	{
		if( (options & URL_SAFE) == URL_SAFE ) return _URL_SAFE_DECODABET;
		else if( (options & ORDERED) == ORDERED ) return _ORDERED_DECODABET;
		else return _STANDARD_DECODABET;

	}	// end getAlphabet



    /** Defeats instantiation. */
    private Base64(){}


    /**
     * Encodes or decodes two files from the command line;
     * <strong>feel free to delete this method (in fact you probably should)
     * if you're embedding this code into a larger program.</strong>
     */
    public final static void main( String[] args )
    {
        if( args.length < 3 ){
            usage("Not enough arguments.");
        }   // end if: args.length < 3
        else {
            String flag = args[0];
            String infile = args[1];
            String outfile = args[2];
            if( flag.equals( "-e" ) ){
                Base64.encodeFileToFile( infile, outfile );
            }   // end if: encode
            else if( flag.equals( "-d" ) ) {
                Base64.decodeFileToFile( infile, outfile );
            }   // end else if: decode
            else {
                usage( "Unknown flag: " + flag );
            }   // end else
        }   // end else
    }   // end main

    /**
     * Prints command line usage.
     *
     * @param msg A message to include with usage info.
     */
    private final static void usage( String msg )
    {
        System.err.println( msg );
        System.err.println( "Usage: java Base64 -e|-d inputfile outputfile" );
    }   // end usage


/* ********  E N C O D I N G   M E T H O D S  ******** */


    /**
     * Encodes up to the first three bytes of array <var>threeBytes</var>
     * and returns a four-byte array in Base64 notation.
     * The actual number of significant bytes in your array is
     * given by <var>numSigBytes</var>.
     * The array <var>threeBytes</var> needs only be as big as
     * <var>numSigBytes</var>.
     * Code can reuse a byte array by passing a four-byte array as <var>b4</var>.
     *
     * @param b4 A reusable byte array to reduce array instantiation
     * @param threeBytes the array to convert
     * @param numSigBytes the number of significant bytes in your array
     * @return four byte array in Base64 notation.
     * @since 1.5.1
     */
    private static byte[] encode3to4( byte[] b4, byte[] threeBytes, int numSigBytes, int options )
    {
        encode3to4( threeBytes, 0, numSigBytes, b4, 0, options );
        return b4;
    }   // end encode3to4


    /**
     * <p>Encodes up to three bytes of the array <var>source</var>
     * and writes the resulting four Base64 bytes to <var>destination</var>.
     * The source and destination arrays can be manipulated
     * anywhere along their length by specifying
     * <var>srcOffset</var> and <var>destOffset</var>.
     * This method does not check to make sure your arrays
     * are large enough to accomodate <var>srcOffset</var> + 3 for
     * the <var>source</var> array or <var>destOffset</var> + 4 for
     * the <var>destination</var> array.
     * The actual number of significant bytes in your array is
     * given by <var>numSigBytes</var>.</p>
	 * <p>This is the lowest level of the encoding methods with
	 * all possible parameters.</p>
     *
     * @param source the array to convert
     * @param srcOffset the index where conversion begins
     * @param numSigBytes the number of significant bytes in your array
     * @param destination the array to hold the conversion
     * @param destOffset the index where output will be put
     * @return the <var>destination</var> array
     * @since 1.3
     */
    private static byte[] encode3to4(
     byte[] source, int srcOffset, int numSigBytes,
     byte[] destination, int destOffset, int options )
    {
		byte[] ALPHABET = getAlphabet( options );

        //           1         2         3
        // 01234567890123456789012345678901 Bit position
        // --------000000001111111122222222 Array position from threeBytes
        // --------|    ||    ||    ||    | Six bit groups to index ALPHABET
        //          >>18  >>12  >> 6  >> 0  Right shift necessary
        //                0x3f  0x3f  0x3f  Additional AND

        // Create buffer with zero-padding if there are only one or two
        // significant bytes passed in the array.
        // We have to shift left 24 in order to flush out the 1's that appear
        // when Java treats a value as negative that is cast from a byte to an int.
        int inBuff =   ( numSigBytes > 0 ? ((source[ srcOffset     ] << 24) >>>  8) : 0 )
                     | ( numSigBytes > 1 ? ((source[ srcOffset + 1 ] << 24) >>> 16) : 0 )
                     | ( numSigBytes > 2 ? ((source[ srcOffset + 2 ] << 24) >>> 24) : 0 );

        switch( numSigBytes )
        {
            case 3:
                destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
                destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
                destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>>  6) & 0x3f ];
                destination[ destOffset + 3 ] = ALPHABET[ (inBuff       ) & 0x3f ];
                return destination;

            case 2:
                destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
                destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
                destination[ destOffset + 2 ] = ALPHABET[ (inBuff >>>  6) & 0x3f ];
                destination[ destOffset + 3 ] = EQUALS_SIGN;
                return destination;

            case 1:
                destination[ destOffset     ] = ALPHABET[ (inBuff >>> 18)        ];
                destination[ destOffset + 1 ] = ALPHABET[ (inBuff >>> 12) & 0x3f ];
                destination[ destOffset + 2 ] = EQUALS_SIGN;
                destination[ destOffset + 3 ] = EQUALS_SIGN;
                return destination;

            default:
                return destination;
        }   // end switch
    }   // end encode3to4



    /**
     * Serializes an object and returns the Base64-encoded
     * version of that serialized object. If the object
     * cannot be serialized or there is another error,
     * the method will return <tt>null</tt>.
     * The object is not GZip-compressed before being encoded.
     *
     * @param serializableObject The object to encode
     * @return The Base64-encoded object
     * @since 1.4
     */
    public static String encodeObject( java.io.Serializable serializableObject )
    {
        return encodeObject( serializableObject, NO_OPTIONS );
    }   // end encodeObject



    /**
     * Serializes an object and returns the Base64-encoded
     * version of that serialized object. If the object
     * cannot be serialized or there is another error,
     * the method will return <tt>null</tt>.
     * <p>
     * Valid options:<pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DONT_BREAK_LINES: don't break lines at 76 characters
     *     <i>Note: Technically, this makes your encoding non-compliant.</i>
     * </pre>
     * <p>
     * Example: <code>encodeObject( myObj, Base64.GZIP )</code> or
     * <p>
     * Example: <code>encodeObject( myObj, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     *
     * @param serializableObject The object to encode
     * @param options Specified options
     * @return The Base64-encoded object
     * @see Base64#GZIP
     * @see Base64#DONT_BREAK_LINES
     * @since 2.0
     */
    public static String encodeObject( java.io.Serializable serializableObject, int options )
    {
        // Streams
        java.io.ByteArrayOutputStream  baos  = null;
        java.io.OutputStream           b64os = null;
        java.io.ObjectOutputStream     oos   = null;
        java.util.zip.GZIPOutputStream gzos  = null;

        // Isolate options
        int gzip           = (options & GZIP);
        int dontBreakLines = (options & DONT_BREAK_LINES);

        try
        {
            // ObjectOutputStream -> (GZIP) -> Base64 -> ByteArrayOutputStream
            baos  = new java.io.ByteArrayOutputStream();
            b64os = new Base64.OutputStream( baos, ENCODE | options );

            // GZip?
            if( gzip == GZIP )
            {
                gzos = new java.util.zip.GZIPOutputStream( b64os );
                oos  = new java.io.ObjectOutputStream( gzos );
            }   // end if: gzip
            else
                oos   = new java.io.ObjectOutputStream( b64os );

            oos.writeObject( serializableObject );
        }   // end try
        catch( java.io.IOException e )
        {
            e.printStackTrace();
            return null;
        }   // end catch
        finally
        {
            try{ oos.close();   } catch( Exception e ){}
            try{ gzos.close();  } catch( Exception e ){}
            try{ b64os.close(); } catch( Exception e ){}
            try{ baos.close();  } catch( Exception e ){}
        }   // end finally

        // Return value according to relevant encoding.
        try
        {
            return new String( baos.toByteArray(), PREFERRED_ENCODING );
        }   // end try
        catch (java.io.UnsupportedEncodingException uue)
        {
            return new String( baos.toByteArray() );
        }   // end catch

    }   // end encode



    /**
     * Encodes a byte array into Base64 notation.
     * Does not GZip-compress data.
     *
     * @param source The data to convert
     * @since 1.4
     */
    public static String encodeBytes( byte[] source )
    {
        return encodeBytes( source, 0, source.length, NO_OPTIONS );
    }   // end encodeBytes



    /**
     * Encodes a byte array into Base64 notation.
     * <p>
     * Valid options:<pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DONT_BREAK_LINES: don't break lines at 76 characters
     *     <i>Note: Technically, this makes your encoding non-compliant.</i>
     * </pre>
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     *
     *
     * @param source The data to convert
     * @param options Specified options
     * @see Base64#GZIP
     * @see Base64#DONT_BREAK_LINES
     * @since 2.0
     */
    public static String encodeBytes( byte[] source, int options )
    {
        return encodeBytes( source, 0, source.length, options );
    }   // end encodeBytes


    /**
     * Encodes a byte array into Base64 notation.
     * Does not GZip-compress data.
     *
     * @param source The data to convert
     * @param off Offset in array where conversion should begin
     * @param len Length of data to convert
     * @since 1.4
     */
    public static String encodeBytes( byte[] source, int off, int len )
    {
        return encodeBytes( source, off, len, NO_OPTIONS );
    }   // end encodeBytes



    /**
     * Encodes a byte array into Base64 notation.
     * <p>
     * Valid options:<pre>
     *   GZIP: gzip-compresses object before encoding it.
     *   DONT_BREAK_LINES: don't break lines at 76 characters
     *     <i>Note: Technically, this makes your encoding non-compliant.</i>
     * </pre>
     * <p>
     * Example: <code>encodeBytes( myData, Base64.GZIP )</code> or
     * <p>