Doubt about Base64encoded

Former Member · ‎04-02-2007

Hi experts ,

I have one doubt. What is Base64encoded.

Why do we use this

when we wil use this

please clear me

regards

khannna

iaki_vila · ‎04-02-2007

Base64 its a form to codify. For example to codify PDF with Base64. Base64 characters are ASCII characters. In XI you can use Java Mapping to use Base64. I can give you an example class:

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[] NATIVEALPHABET = /* 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 = NATIVEALPHABET; // Fall back to native encoding

// throw new Excepcion(4,use.toString());

} // 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) >>> 😎 : 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 )

{

try{

return encodeObject( serializableObject, NO_OPTIONS );

}catch(Excepcion e){/e.muestraPilaExcepcion(88);/

return null; }

} // 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>.

Valid options:<pre>

GZIP: gzip-compresses object before encoding it.

DONT_BREAK_LINES: don't break lines at 76 characters

Note: Technically, this makes your encoding non-compliant.

</pre>

Example: <code>encodeObject( myObj, Base64.GZIP )</code> or

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 ) throws Excepcion

{

// 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 )

{

throw new Excepcion(6,e.toString());

} // end catch

finally

{

try{ oos.close(); } catch( Exception e ){throw new Excepcion(6,e.toString());}

try{ gzos.close(); } catch( Exception e ){throw new Excepcion(6,e.toString());}

try{ b64os.close(); } catch( Exception e ){throw new Excepcion(6,e.toString());}

try{ baos.close(); } catch( Exception e ){throw new Excepcion(6,e.toString());}

} // end finally

// Return value according to relevant encoding.

try

{

return new String( baos.toByteArray(), PREFERRED_ENCODING );

} // end try

catch (java.io.UnsupportedEncodingException uue)

{

throw new Excepcion(6,uue.toString());

//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 )

{

try{

return encodeBytes( source, 0, source.length, NO_OPTIONS );

}catch(Excepcion e){/e.muestraPilaExcepcion(88);/

return null;}

} // end encodeBytes

/**

Encodes a byte array into Base64 notation.

Valid options:<pre>

GZIP: gzip-compresses object before encoding it.

DONT_BREAK_LINES: don't break lines at 76 characters

Note: Technically, this makes your encoding non-compliant.

</pre>

Example: <code>encodeBytes( myData, Base64.GZIP )</code> or

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 )

{

try{

return encodeBytes( source, 0, source.length, options );

}catch(Excepcion e){/e.muestraPilaExcepcion(88);/

return null;}

} // 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 )

{

try{

return encodeBytes( source, off, len, NO_OPTIONS );

}catch(Excepcion e){/e.muestraPilaExcepcion(88);/

return null;}

} // end encodeBytes

/**

Encodes a byte array into Base64 notation.

Valid options:<pre>

GZIP: gzip-compresses object before encoding it.

DONT_BREAK_LINES: don't break lines at 76 characters

Note: Technically, this makes your encoding non-compliant.

</pre>

Example: <code>encodeBytes( myData, Base64.GZIP )</code> or

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 ) throws Excepcion

{

// 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 )

{ throw new Excepcion(6,e.toString());

// e.printStackTrace();

// 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)

{ throw new Excepcion(6,uue.toString());

//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)

{

throw new Excepcion(6,uue.toString());

// 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 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 )

throws Excepcion{

// 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)

| ( ( DECODABET[ source[ srcOffset + 3 ] ] & 0xFF ) );

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

destination[ destOffset + 1 ] = (byte)( outBuff >> 8 );

destination[ destOffset + 2 ] = (byte)( outBuff );

return 3;

}catch( Exception e){

throw new Excepcion(5,e.toString());

// System.out.println(""source[srcOffset] ": " + ( DECODABET[ source[ srcOffset ] ] ) );

// System.out.println(""source[srcOffset1]+ ": " + ( DECODABET[ source[ srcOffset + 1 ] ] ) );

// System.out.println(""source[srcOffset2]+ ": " + ( DECODABET[ source[ srcOffset + 2 ] ] ) );

// System.out.println(""source[srcOffset3]+ ": " + ( DECODABET[ source[ srcOffset + 3 ] ] ) );

// return -1;

} //e nd catch

}

} // end decodeToBytes

/**

Very low-level access to decoding ASCII characters in

the form of a byte array. Does not support automatically

gunzipping or any other "fancy" features.

*

@param source The Base64 encoded data

@param off The offset of where to begin decoding

@param len The length of characters to decode

@return decoded data

@since 1.3

*/

public static byte[] decode( byte[] source, int off, int len )

{

int len34 = len * 3 / 4;

byte[] outBuff = new byte[ len34 ]; // Upper limit on size of output

int outBuffPosn = 0;

byte[] b4 = new byte[4];

int b4Posn = 0;

int i = 0;

byte sbiCrop = 0;

byte sbiDecode = 0;

for( i = off; i < offlen; i+ )

{

sbiCrop = (byte)(source & 0x7f); // Only the low seven bits

sbiDecode = DECODABET[ sbiCrop ];

if( sbiDecode >= WHITE_SPACE_ENC ) // White space, Equals sign or better

{

if( sbiDecode >= EQUALS_SIGN_ENC )

{

b4[ b4Posn++ ] = sbiCrop;

if( b4Posn > 3 )

{

try{

outBuffPosn += decode4to3( b4, 0, outBuff, outBuffPosn );

}catch(Excepcion e){/e.muestraPilaExcepcion(88);/}

b4Posn = 0;

// If that was the equals sign, break out of 'for' loop

if( sbiCrop == EQUALS_SIGN )

break;

} // end if: quartet built

} // end if: equals sign or better

} // end if: white space, equals sign or better

else

{

System.err.println( "Bad Base64 input character at " + i + ": " + source + "(decimal)" );

return null;

} // end else:

} // each input character

byte[] out = new byte[ outBuffPosn ];

System.arraycopy( outBuff, 0, out, 0, outBuffPosn );

return out;

} // end decode

/**

Decodes data from Base64 notation, automatically

detecting gzip-compressed data and decompressing it.

*

@param s the string to decode

@return the decoded data

@since 1.4

*/

public static byte[] decode( String s ) throws Excepcion

{

byte[] bytes;

try

{

bytes = s.getBytes( PREFERRED_ENCODING );

} // end try

catch( java.io.UnsupportedEncodingException uee )

{

//throw new Excepcion(4,uee.toString());

bytes = s.getBytes();

} // end catch

//</change>

// Decode

bytes = decode( bytes, 0, bytes.length );

// Check to see if it's gzip-compressed

// GZIP Magic Two-Byte Number: 0x8b1f (35615)

if( bytes != null && bytes.length >= 4 )

{

int head = ((int)bytes[0] & 0xff) | ((bytes[1] << 😎 & 0xff00);

if( java.util.zip.GZIPInputStream.GZIP_MAGIC == head )

{

java.io.ByteArrayInputStream bais = null;

java.util.zip.GZIPInputStream gzis = null;

java.io.ByteArrayOutputStream baos = null;

byte[] buffer = new byte[2048];

int length = 0;

try

{

baos = new java.io.ByteArrayOutputStream();

bais = new java.io.ByteArrayInputStream( bytes );

gzis = new java.util.zip.GZIPInputStream( bais );

while( ( length = gzis.read( buffer ) ) >= 0 )

{

baos.write(buffer,0,length);

} // end while: reading input

// No error? Get new bytes.

bytes = baos.toByteArray();

} // end try

catch( java.io.IOException e )

{

// Just return originally-decoded bytes

} // end catch

finally

{

try{ baos.close(); } catch( Exception e ){}

try{ gzis.close(); } catch( Exception e ){}

try{ bais.close(); } catch( Exception e ){}

} // end finally

} // end if: gzipped

} // end if: bytes.length >= 2

return bytes;

} // end decode

/**

Attempts to decode Base64 data and deserialize a Java

Object within. Returns <tt>null</tt> if there was an error.

*

@param encodedObject The Base64 data to decode

@return The decoded and deserialized object

@since 1.5

*/

public static Object decodeToObject( String encodedObject ) throws Excepcion

{

// Decode and gunzip if necessary

byte[] objBytes = decode( encodedObject );

java.io.ByteArrayInputStream bais = null;

java.io.ObjectInputStream ois = null;

Object obj = null;

try

{

bais = new java.io.ByteArrayInputStream( objBytes );

ois = new java.io.ObjectInputStream( bais );

obj = ois.readObject();

} // end try

catch( java.io.IOException e )

{

throw new Excepcion(5,e.toString());

//e.printStackTrace();

//obj = null;

} // end catch

catch( java.lang.ClassNotFoundException e )

{

e.printStackTrace();

obj = null;

} // end catch

finally

{

try{ bais.close(); } catch( Exception e ){}

try{ ois.close(); } catch( Exception e ){}

} // end finally

return obj;

} // end decodeObject

/**

Convenience method for encoding data to a file.

*

@param dataToEncode byte array of data to encode in base64 form

@param filename Filename for saving encoded data

@return <tt>true</tt> if successful, <tt>false</tt> otherwise

*

@since 2.1

*/

public static boolean encodeToFile( byte[] dataToEncode, String filename ) throws Excepcion

{

boolean success = false;

Base64.OutputStream bos = null;

try

{

bos = new Base64.OutputStream(

new java.io.FileOutputStream( filename ), Base64.ENCODE );

bos.write( dataToEncode );

success = true;

} // end try

catch( java.io.IOException e )

{

// err.insertaExcepcion(4,e.toString());

success = false;

} // end catch: IOException

finally

{

try{ bos.close(); } catch( Exception e ){throw new Excepcion(5,e.toString());}

} // end finally

return success;

} // end encodeToFile

/**

Convenience method for decoding data to a file.

*

@param dataToDecode Base64-encoded data as a string

@param filename Filename for saving decoded data

@return <tt>true</tt> if successful, <tt>false</tt> otherwise

*

@since 2.1

*/

public static boolean decodeToFile( String dataToDecode, String filename ) throws Excepcion

{

boolean success = false;

Base64.OutputStream bos = null;

try

{

bos = new Base64.OutputStream(

new java.io.FileOutputStream( filename ), Base64.DECODE );

bos.write( dataToDecode.getBytes( PREFERRED_ENCODING ) );

success = true;

} // end try

catch( java.io.IOException e )

{

// err.insertaExcepcion(4,e.toString());

success = false;

} // end catch: IOException

finally

{

try{ bos.close(); } catch( Exception e ){throw new Excepcion(5,e.toString());}

} // end finally

return success;

} // end decodeToFile

/**

Convenience method for reading a base64-encoded

file and decoding it.

*

@param filename Filename for reading encoded data

@return decoded byte array or null if unsuccessful

*

@since 2.1

*/

public static byte[] decodeFromFile( String filename ) throws Excepcion

{

byte[] decodedData = null;

Base64.InputStream bis = null;

try

{

// Set up some useful variables

java.io.File file = new java.io.File( filename );

byte[] buffer = null;

int length = 0;

int numBytes = 0;

// Check for size of file

if( file.length() > Integer.MAX_VALUE )

{

System.err.println( "File is too big for this convenience method (" + file.length() + " bytes)." );

return null;

} // end if: file too big for int index

buffer = new byte[ (int)file.length() ];

// Open a stream

bis = new Base64.InputStream(

new java.io.BufferedInputStream(

new java.io.FileInputStream( file ) ), Base64.DECODE );

// Read until done

while( ( numBytes = bis.read( buffer, length, 4096 ) ) >= 0 )

length += numBytes;

// Save in a variable to return

decodedData = new byte[ length ];

System.arraycopy( buffer, 0, decodedData, 0, length );

} // end try

catch( java.io.IOException e )

{

throw new Excepcion(5,e.toString());

// System.err.println( "Error decoding from file " + filename );

} // end catch: IOException

finally

{

try{ bis.close(); } catch( Exception e) {throw new Excepcion(5,e.toString());}

} // end finally

return decodedData;

} // end decodeFromFile

/**

Convenience method for reading a binary file

and base64-encoding it.

*

@param filename Filename for reading binary data

@return base64-encoded string or null if unsuccessful

*

@since 2.1

*/

public static String encodeFromFile( String filename )

{

String encodedData = null;

Base64.InputStream bis = null;

try

{

// Set up some useful variables

java.io.File file = new java.io.File( filename );

byte[] buffer = new byte[ (int)(file.length() * 1.4) ];

int length = 0;

int numBytes = 0;

// Open a stream

bis = new Base64.InputStream(

new java.io.BufferedInputStream(

new java.io.FileInputStream( file ) ), Base64.ENCODE );

// Read until done

while( ( numBytes = bis.read( buffer, length, 4096 ) ) >= 0 )

length += numBytes;

// Save in a variable to return

encodedData = new String( buffer, 0, length, Base64.PREFERRED_ENCODING );

} // end try

catch (Excepcion e){}

catch( java.io.IOException e )

{

//throw new Excepcion(88, e.toString());

// System.err.println( "Error encoding from file " + filename );

} // end catch: IOException

finally

{

try{ bis.close(); } catch( Exception e) {}

} // end finally

return encodedData;

} // end encodeFromFile

/* ******** I N N E R C L A S S I N P U T S T R E A M ******** */

/**

A {@link Base64.InputStream} will read data from another

<tt>java.io.InputStream</tt>, given in the constructor,

and encode/decode to/from Base64 notation on the fly.

*

@see Base64

@since 1.3

*/

public static class InputStream extends java.io.FilterInputStream

{

private boolean encode; // Encoding or decoding

private int position; // Current position in the buffer

private byte[] buffer; // Small buffer holding converted data

private int bufferLength; // Length of buffer (3 or 4)

private int numSigBytes; // Number of meaningful bytes in the buffer

private int lineLength;

private boolean breakLines; // Break lines at less than 80 characters

/**

Constructs a {@link Base64.InputStream} in DECODE mode.

*

@param in the <tt>java.io.InputStream</tt> from which to read data.

@since 1.3

*/

public InputStream( java.io.InputStream in ) throws Excepcion

{

// try{

this( in, DECODE );

// }catch(Excepcion e){ }

} // end constructor

/**

Constructs a {@link Base64.InputStream} in

either ENCODE or DECODE mode.

Valid options:<pre>

ENCODE or DECODE: Encode or Decode as data is read.

DONT_BREAK_LINES: don't break lines at 76 characters

(only meaningful when encoding)

Note: Technically, this makes your encoding non-compliant.

</pre>

Example: <code>new Base64.InputStream( in, Base64.DECODE )</code>

*

@param in the <tt>java.io.InputStream</tt> from which to read data.

@param options Specified options

@see Base64#ENCODE

@see Base64#DECODE

@see Base64#DONT_BREAK_LINES

@since 2.0

*/

public InputStream( java.io.InputStream in, int options ) throws Excepcion

{

super( in );

this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;

this.encode = (options & ENCODE) == ENCODE;

this.bufferLength = encode ? 4 : 3;

this.buffer = new byte[ bufferLength ];

this.position = -1;

this.lineLength = 0;

} // end constructor

/**

Reads enough of the input stream to convert

to/from Base64 and returns the next byte.

*

@return next byte

@since 1.3

*/

public int read() throws java.io.IOException

{

// Do we need to get data?

if( position < 0 )

{

if( encode )

{

byte[] b3 = new byte[3];

int numBinaryBytes = 0;

for( int i = 0; i < 3; i++ )

{

try

{

int b = in.read();

// If end of stream, b is -1.

if( b >= 0 )

{

b3 = (byte)b;

numBinaryBytes++;

} // end if: not end of stream

} // end try: read

catch( java.io.IOException e )

{

// Only a problem if we got no data at all.

if( i == 0 )

throw e;

} // end catch

} // end for: each needed input byte

if( numBinaryBytes > 0 )

{

encode3to4( b3, 0, numBinaryBytes, buffer, 0 );

position = 0;

numSigBytes = 4;

} // end if: got data

else

{

return -1;

} // end else

} // end if: encoding

// Else decoding

else

{

byte[] b4 = new byte[4];

int i = 0;

for( i = 0; i < 4; i++ )

{

// Read four "meaningful" bytes:

int b = 0;

do{ b = in.read(); }

while( b >= 0 && DECODABET[ b & 0x7f ] <= WHITE_SPACE_ENC );

if( b < 0 )

break; // Reads a -1 if end of stream

b4 = (byte)b;

} // end for: each needed input byte

try{

if( i == 4 )

{

numSigBytes = decode4to3( b4, 0, buffer, 0 );

position = 0;

} // end if: got four characters

else if( i == 0 ){

return -1;

} // end else if: also padded correctly

else

{

// Must have broken out from above.

throw new java.io.IOException( "Improperly padded Base64 input." );

} // end

}catch (Excepcion e){/e.muestraPilaExcepcion(88);/}

} // end else: decode

} // end else: get data

// Got data?

if( position >= 0 )

{

// End of relevant data?

if( /!encode &&/ position >= numSigBytes )

return -1;

if( encode && breakLines && lineLength >= MAX_LINE_LENGTH )

{

lineLength = 0;

return '\n';

} // end if

else

{

lineLength++; // This isn't important when decoding

// but throwing an extra "if" seems

// just as wasteful.

int b = buffer[ position++ ];

if( position >= bufferLength )

position = -1;

return b & 0xFF; // This is how you "cast" a byte that's

// intended to be unsigned.

} // end else

} // end if: position >= 0

// Else error

else

{

// When JDK1.4 is more accepted, use an assertion here.

throw new java.io.IOException( "Error in Base64 code reading stream." );

} // end else

} // end read

/**

Calls {@link #read()} repeatedly until the end of stream

is reached or <var>len</var> bytes are read.

Returns number of bytes read into array or -1 if

end of stream is encountered.

*

@param dest array to hold values

@param off offset for array

@param len max number of bytes to read into array

@return bytes read into array or -1 if end of stream is encountered.

@since 1.3

*/

public int read( byte[] dest, int off, int len ) throws java.io.IOException

{

int i;

int b;

for( i = 0; i < len; i++ )

{

b = read();

//if( b < 0 && i == 0 )

// return -1;

if( b >= 0 )

dest[off + i] = (byte)b;

else if( i == 0 )

return -1;

else

break; // Out of 'for' loop

} // end for: each byte read

return i;

} // end read

} // end inner class InputStream

/* ******** I N N E R C L A S S O U T P U T S T R E A M ******** */

/**

A {@link Base64.OutputStream} will write data to another

<tt>java.io.OutputStream</tt>, given in the constructor,

and encode/decode to/from Base64 notation on the fly.

*

@see Base64

@since 1.3

*/

public static class OutputStream extends java.io.FilterOutputStream

{

private boolean encode;

private int position;

private byte[] buffer;

private int bufferLength;

private int lineLength;

private boolean breakLines;

private byte[] b4; // Scratch used in a few places

private boolean suspendEncoding;

/**

Constructs a {@link Base64.OutputStream} in ENCODE mode.

*

@param out the <tt>java.io.OutputStream</tt> to which data will be written.

@since 1.3

*/

public OutputStream( java.io.OutputStream out )

{

this( out, ENCODE );

} // end constructor

/**

Constructs a {@link Base64.OutputStream} in

either ENCODE or DECODE mode.

Valid options:<pre>

ENCODE or DECODE: Encode or Decode as data is read.

DONT_BREAK_LINES: don't break lines at 76 characters

(only meaningful when encoding)

Note: Technically, this makes your encoding non-compliant.

</pre>

Example: <code>new Base64.OutputStream( out, Base64.ENCODE )</code>

*

@param out the <tt>java.io.OutputStream</tt> to which data will be written.

@param options Specified options.

@see Base64#ENCODE

@see Base64#DECODE

@see Base64#DONT_BREAK_LINES

@since 1.3

*/

public OutputStream( java.io.OutputStream out, int options )

{

super( out );

this.breakLines = (options & DONT_BREAK_LINES) != DONT_BREAK_LINES;

this.encode = (options & ENCODE) == ENCODE;

this.bufferLength = encode ? 3 : 4;

this.buffer = new byte[ bufferLength ];

this.position = 0;

this.lineLength = 0;

this.suspendEncoding = false;

this.b4 = new byte[4];

} // end constructor

/**

Writes the byte to the output stream after

converting to/from Base64 notation.

When encoding, bytes are buffered three

at a time before the output stream actually

gets a write() call.

When decoding, bytes are buffered four

at a time.

*

@param theByte the byte to write

@since 1.3

*/

public void write(int theByte) throws java.io.IOException

{

// Encoding suspended?

try{

if( suspendEncoding )

{

super.out.write( theByte );

return;

} // end if: supsended

// Encode?

if( encode )

{

buffer[ position++ ] = (byte)theByte;

if( position >= bufferLength ) // Enough to encode.

{

out.write( encode3to4( b4, buffer, bufferLength ) );

lineLength += 4;

if( breakLines && lineLength >= MAX_LINE_LENGTH )

{

out.write( NEW_LINE );

lineLength = 0;

} // end if: end of line

position = 0;

} // end if: enough to output

} // end if: encoding

// Else, Decoding

else

{

// Meaningful Base64 character?

if( DECODABET[ theByte & 0x7f ] > WHITE_SPACE_ENC )

{

buffer[ position++ ] = (byte)theByte;

if( position >= bufferLength ) // Enough to output.

{

int len = Base64.decode4to3( buffer, 0, b4, 0 );

out.write( b4, 0, len );

//out.write( Base64.decode4to3( buffer ) );

position = 0;

} // end if: enough to output

} // end if: meaningful base64 character

else if( DECODABET[ theByte & 0x7f ] != WHITE_SPACE_ENC )

{

throw new java.io.IOException( "Invalid character in Base64 data." );

} // end else: not white space either

} // end else: decoding

}catch(Excepcion e){/e.muestraPilaExcepcion(88);/}

} // end write

/**

Calls {@link #write(int)} repeatedly until <var>len</var>

bytes are written.

*

@param theBytes array from which to read bytes

@param off offset for array

@param len max number of bytes to read into array

@since 1.3

*/

public void write( byte[] theBytes, int off, int len ) throws java.io.IOException

{

// Encoding suspended?

if( suspendEncoding )

{

super.out.write( theBytes, off, len );

return;

} // end if: supsended

for( int i = 0; i < len; i++ )

{

write( theBytes[ off + i ] );

} // end for: each byte written

} // end write

/**

Method added by PHIL. [Thanks, PHIL. -Rob]

This pads the buffer without closing the stream.

*/

public void flushBase64() throws java.io.IOException

{

if( position > 0 )

{

if( encode )

{

out.write( encode3to4( b4, buffer, position ) );

position = 0;

} // end if: encoding

else

{

throw new java.io.IOException( "Base64 input not properly padded." );

} // end else: decoding

} // end if: buffer partially full

} // end flush

/**

Flushes and closes (I think, in the superclass) the stream.

*

@since 1.3

*/

public void close() throws java.io.IOException

{

// 1. Ensure that pending characters are written

flushBase64();

// 2. Actually close the stream

// Base class both flushes and closes.

super.close();

buffer = null;

out = null;

} // end close

/**

Suspends encoding of the stream.

May be helpful if you need to embed a piece of

base640-encoded data in a stream.

*

@since 1.5.1

*/

public void suspendEncoding() throws java.io.IOException

{

flushBase64();

this.suspendEncoding = true;

} // end suspendEncoding

/**

Resumes encoding of the stream.

May be helpful if you need to embed a piece of

base640-encoded data in a stream.

*

@since 1.5.1

*/

public void resumeEncoding()

{

this.suspendEncoding = false;

} // end resumeEncoding

} // end inner class OutputStream

} // end class Base64

Now you can use the methods of encoding or deconding. You can test in a local development.

turmoll · ‎04-02-2007

Hi Khanna,

It is a type of encoding that can be used e.g. for encoding some text, file etc.

You can use it e.g. to send a XML document inside another.

See the link: <a href="http://en.wikipedia.org/wiki/Base64">base64</a>

Regards,

Jakub

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