base64.java.svn-base

来自「开源项目openfire的完整源程序」· SVN-BASE 代码 · 共 1,237 行 · 第 1/4 页

        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 | dontBreakLines);

            // 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) {
            Log.error(e);
            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/>
     * Example: <code>encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )</code>
     *
     * @param source  The data to convert
     * @param off     Offset in array where conversion should begin
     * @param len     Length of 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 off, int len, int options) {
        // Isolate options
        int dontBreakLines = (options & DONT_BREAK_LINES);
        int gzip = (options & GZIP);

        // Compress?
        if (gzip == GZIP) {
            java.io.ByteArrayOutputStream baos = null;
            java.util.zip.GZIPOutputStream gzos = null;
            Base64.OutputStream b64os = null;


            try {
                // GZip -> Base64 -> ByteArray
                baos = new java.io.ByteArrayOutputStream();
                b64os = new Base64.OutputStream(baos, ENCODE | dontBreakLines);
                gzos = new java.util.zip.GZIPOutputStream(b64os);

                gzos.write(source, off, len);
                gzos.close();
            }   // end try
            catch (java.io.IOException e) {
                Log.error(e);
                return null;
            }   // end catch
            finally {
                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 if: compress

        // Else, don't compress. Better not to use streams at all then.
        else {
            // Convert option to boolean in way that code likes it.
            boolean breakLines = dontBreakLines == 0;

            int len43 = len * 4 / 3;
            byte[] outBuff = new byte[(len43)                      // Main 4:3
                    + ((len % 3) > 0 ? 4 : 0)      // Account for padding
                    + (breakLines ? (len43 / MAX_LINE_LENGTH) : 0)]; // New lines
            int d = 0;
            int e = 0;
            int len2 = len - 2;
            int lineLength = 0;
            for (; d < len2; d += 3, e += 4) {
                encode3to4(source, d + off, 3, outBuff, e);

                lineLength += 4;
                if (breakLines && lineLength == MAX_LINE_LENGTH) {
                    outBuff[e + 4] = NEW_LINE;
                    e++;
                    lineLength = 0;
                }   // end if: end of line
            }   // en dfor: each piece of array

            if (d < len) {
                encode3to4(source, d + off, len - d, outBuff, e);
                e += 4;
            }   // end if: some padding needed

            // Return value according to relevant encoding.
            try {
                return new String(outBuff, 0, e, PREFERRED_ENCODING);
            }   // end try
            catch (java.io.UnsupportedEncodingException uue) {
                return new String(outBuff, 0, e);
            }   // end catch

        }   // end else: don't compress

    }   // end encodeBytes

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


    /**
     * Decodes the first four bytes of array <var>fourBytes</var>
     * and returns an array up to three bytes long with the
     * decoded values.
     *
     * @param fourBytes the array with Base64 content
     * @return array with decoded values
     * @since 1.3
     */
    private static byte[] decode4to3(byte[] fourBytes) {
        byte[] outBuff1 = new byte[3];
        int count = decode4to3(fourBytes, 0, outBuff1, 0);
        byte[] outBuff2 = new byte[count];

        for (int i = 0; i < count; i++)
            outBuff2[i] = outBuff1[i];

        return outBuff2;
    }


    /**
     * Decodes four bytes from array <var>source</var>
     * and writes the resulting bytes (up to three of them)
     * 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> + 4 for
     * the <var>source</var> array or <var>destOffset</var> + 3 for
     * the <var>destination</var> array.
     * This method returns the actual number of bytes that
     * were converted from the Base64 encoding.
     *
     * @param source      the array to convert
     * @param srcOffset   the index where conversion begins
     * @param destination the array to hold the conversion
     * @param destOffset  the index where output will be put
     * @return the number of decoded bytes converted
     * @since 1.3
     */
    private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset) {
        // Example: Dk==
        if (source[srcOffset + 2] == EQUALS_SIGN) {
            // Two ways to do the same thing. Don't know which way I like best.
            //int outBuff =   ( ( DECODABET[ source[ srcOffset    ] ] << 24 ) >>>  6 )
            //              | ( ( DECODABET[ source[ srcOffset + 1] ] << 24 ) >>> 12 );
            int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                    | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12);

            destination[destOffset] = (byte)(outBuff >>> 16);
            return 1;
        }

        // Example: DkL=
        else if (source[srcOffset + 3] == EQUALS_SIGN) {
            // Two ways to do the same thing. Don't know which way I like best.
            //int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] << 24 ) >>>  6 )
            //              | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
            //              | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 );
            int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                    | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                    | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6);

            destination[destOffset] = (byte)(outBuff >>> 16);
            destination[destOffset + 1] = (byte)(outBuff >>> 8);
            return 2;
        }

        // Example: DkLE
        else {
            try {
                // Two ways to do the same thing. Don't know which way I like best.
                //int outBuff =   ( ( DECODABET[ source[ srcOffset     ] ] << 24 ) >>>  6 )
                //              | ( ( DECODABET[ source[ srcOffset + 1 ] ] << 24 ) >>> 12 )
                //              | ( ( DECODABET[ source[ srcOffset + 2 ] ] << 24 ) >>> 18 )
                //              | ( ( DECODABET[ source[ srcOffset + 3 ] ] << 24 ) >>> 24 );
                int outBuff = ((DECODABET[source[srcOffset]] & 0xFF) << 18)
                        | ((DECODABET[source[srcOffset + 1]] & 0xFF) << 12)
                        | ((DECODABET[source[srcOffset + 2]] & 0xFF) << 6)