📄 base64.java
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/*
* Created on 2005/10/05
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package za.co.halo.SecureCommunications.util;
/**
* Encodes and decodes to and from Base64 notation.
*
* <p>
* Change Log:
* </p>
* <ul>
* <li>v2.1 - Cleaned up javadoc comments and unused variables and methods. Added
* some convenience methods for reading and writing to and from files.</li>
* <li>v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems
* with other encodings (like EBCDIC).</li>
* <li>v2.0.1 - Fixed an error when decoding a single byte, that is, when the
* encoded data was a single byte.</li>
* <li>v2.0 - I got rid of methods that used booleans to set options.
* Now everything is more consolidated and cleaner. The code now detects
* when data that's being decoded is gzip-compressed and will decompress it
* automatically. Generally things are cleaner. You'll probably have to
* change some method calls that you were making to support the new
* options format (<tt>int</tt>s that you "OR" together).</li>
* <li>v1.5.1 - Fixed bug when decompressing and decoding to a
* byte[] using <tt>decode( String s, boolean gzipCompressed )</tt>.
* Added the ability to "suspend" encoding in the Output Stream so
* you can turn on and off the encoding if you need to embed base64
* data in an otherwise "normal" stream (like an XML file).</li>
* <li>v1.5 - Output stream pases on flush() command but doesn't do anything itself.
* This helps when using GZIP streams.
* Added the ability to GZip-compress objects before encoding them.</li>
* <li>v1.4 - Added helper methods to read/write files.</li>
* <li>v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.</li>
* <li>v1.3.5 - Added flag to turn on and off line breaks. Fixed bug in input stream
* where last buffer being read, if not completely full, was not returned.</li>
* <li>v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.</li>
* <li>v1.3.3 - Fixed I/O streams which were totally messed up.</li>
* </ul>
*
* <p>
* I am placing this code in the Public Domain. Do with it as you will.
* This software comes with no guarantees or warranties but with
* plenty of well-wishing instead!
* Please visit <a href="http://iharder.net/base64">http://iharder.net/base64</a>
* periodically to check for updates or to contribute improvements.
* </p>
*
* @author Robert Harder
* @author rob@iharder.net
* @version 2.1
*/
public class Base64
{
/* ******** P U B L I C F I E L D S ******** */
/** No options specified. Value is zero. */
public final static int NO_OPTIONS = 0;
/** Specify encoding. */
public final static int ENCODE = 1;
/** Specify decoding. */
public final static int DECODE = 0;
/** Specify that data should be gzip-compressed. */
public final static int GZIP = 2;
/** Don't break lines when encoding (violates strict Base64 specification) */
public final static int DONT_BREAK_LINES = 8;
/* ******** P R I V A T E F I E L D S ******** */
/** Maximum line length (76) of Base64 output. */
private final static int MAX_LINE_LENGTH = 76;
/** The equals sign (=) as a byte. */
private final static byte EQUALS_SIGN = (byte)'=';
/** The new line character (\n) as a byte. */
private final static byte NEW_LINE = (byte)'\n';
/** Preferred encoding. */
private final static String PREFERRED_ENCODING = "UTF-8";
/** The 64 valid Base64 values. */
private final static byte[] ALPHABET;
private final static byte[] _NATIVE_ALPHABET = /* May be something funny like EBCDIC */
{
(byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
(byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
(byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
(byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
(byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
(byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
(byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
(byte)'v', (byte)'w', (byte)'x', (byte)'y', (byte)'z',
(byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5',
(byte)'6', (byte)'7', (byte)'8', (byte)'9', (byte)'+', (byte)'/'
};
/** Determine which ALPHABET to use. */
static
{
byte[] __bytes;
try
{
__bytes = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".getBytes( PREFERRED_ENCODING );
} // end try
catch (java.io.UnsupportedEncodingException use)
{
__bytes = _NATIVE_ALPHABET; // Fall back to native encoding
} // end catch
ALPHABET = __bytes;
} // end static
/**
* Translates a Base64 value to either its 6-bit reconstruction value
* or a negative number indicating some other meaning.
**/
private final static byte[] DECODABET =
{
-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 0 - 8
-5,-5, // Whitespace: Tab and Linefeed
-9,-9, // Decimal 11 - 12
-5, // Whitespace: Carriage Return
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 14 - 26
-9,-9,-9,-9,-9, // Decimal 27 - 31
-5, // Whitespace: Space
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 33 - 42
62, // Plus sign at decimal 43
-9,-9,-9, // Decimal 44 - 46
63, // Slash at decimal 47
52,53,54,55,56,57,58,59,60,61, // Numbers zero through nine
-9,-9,-9, // Decimal 58 - 60
-1, // Equals sign at decimal 61
-9,-9,-9, // Decimal 62 - 64
0,1,2,3,4,5,6,7,8,9,10,11,12,13, // Letters 'A' through 'N'
14,15,16,17,18,19,20,21,22,23,24,25, // Letters 'O' through 'Z'
-9,-9,-9,-9,-9,-9, // Decimal 91 - 96
26,27,28,29,30,31,32,33,34,35,36,37,38, // Letters 'a' through 'm'
39,40,41,42,43,44,45,46,47,48,49,50,51, // Letters 'n' through 'z'
-9,-9,-9,-9 // Decimal 123 - 126
/*,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 127 - 139
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 140 - 152
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 153 - 165
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 166 - 178
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 179 - 191
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 192 - 204
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 205 - 217
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 218 - 230
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9, // Decimal 231 - 243
-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9,-9 // Decimal 244 - 255 */
};
// I think I end up not using the BAD_ENCODING indicator.
//private final static byte BAD_ENCODING = -9; // Indicates error in encoding
private final static byte WHITE_SPACE_ENC = -5; // Indicates white space in encoding
private final static byte EQUALS_SIGN_ENC = -1; // Indicates equals sign in encoding
/** Defeats instantiation. */
private Base64(){}
/* ******** 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 )
{
encode3to4( threeBytes, 0, numSigBytes, b4, 0 );
return b4;
} // end encode3to4
/**
* 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>.
*
* @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 )
{
// 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 | 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 )
{
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
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