public class

Base64Harder

extends Object
java.lang.Object
   ↳ com.microstrategy.utils.Base64Harder

Class Overview

Encodes and decodes to and from Base64 notation.

Homepage: http://iharder.net/base64.

The options parameter, which appears in a few places, is used to pass several pieces of information to the encoder. In the "higher level" methods such as encodeBytes( bytes, options ) the options parameter can be used to indicate such things as first gzipping the bytes before encoding them, not inserting linefeeds (though that breaks strict Base64 compatibility), and encoding using the URL-safe and Ordered dialects.

The constants defined in Base64 can be OR-ed together to combine options, so you might make a call like this:

String encoded = Base64.encodeBytes( mybytes, Base64.GZIP | Base64.DONT_BREAK_LINES );

to compress the data before encoding it and then making the output have no newline characters.

Change Log:

  • v2.2.2 - Fixed encodeFileToFile and decodeFileToFile to use the Base64.InputStream class to encode and decode on the fly which uses less memory than encoding/decoding an entire file into memory before writing.
  • v2.2.1 - Fixed bug using URL_SAFE and ORDERED encodings. Fixed bug when using very small files (~< 40 bytes).
  • v2.2 - Added some helper methods for encoding/decoding directly from one file to the next. Also added a main() method to support command line encoding/decoding from one file to the next. Also added these Base64 dialects:
    1. The default is RFC3548 format.
    2. Calling Base64.setFormat(Base64.BASE64_FORMAT.URLSAFE_FORMAT) generates URL and file name friendly format as described in Section 4 of RFC3548. http://www.faqs.org/rfcs/rfc3548.html
    3. Calling Base64.setFormat(Base64.BASE64_FORMAT.ORDERED_FORMAT) generates URL and file name friendly format that preserves lexical ordering as described in http://www.faqs.org/qa/rfcc-1940.html
    Special thanks to Jim Kellerman at http://www.powerset.com/ for contributing the new Base64 dialects.
  • v2.1 - Cleaned up javadoc comments and unused variables and methods. Added some convenience methods for reading and writing to and from files.
  • v2.0.2 - Now specifies UTF-8 encoding in places where the code fails on systems with other encodings (like EBCDIC).
  • v2.0.1 - Fixed an error when decoding a single byte, that is, when the encoded data was a single byte.
  • 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 (ints that you "OR" together).
  • v1.5.1 - Fixed bug when decompressing and decoding to a byte[] using decode( String s, boolean gzipCompressed ). 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).
  • 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.
  • v1.4 - Added helper methods to read/write files.
  • v1.3.6 - Fixed OutputStream.flush() so that 'position' is reset.
  • 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.
  • v1.3.4 - Fixed when "improperly padded stream" error was thrown at the wrong time.
  • v1.3.3 - Fixed I/O streams which were totally messed up.

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 http://iharder.net/base64 periodically to check for updates or to contribute improvements.

Summary

Nested Classes
class Base64Harder.InputStream A Base64Harder.InputStream will read data from another java.io.InputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly. 
class Base64Harder.OutputStream A Base64Harder.OutputStream will write data to another java.io.OutputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly. 
Constants
int DECODE Specify decoding.
int DONT_BREAK_LINES Don't break lines when encoding (violates strict Base64 specification)
int ENCODE Specify encoding.
int GZIP Specify that data should be gzip-compressed.
int NO_OPTIONS No options specified.
int ORDERED Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.
int URL_SAFE Encode using Base64-like encoding that is URL- and Filename-safe as described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html.
Public Methods
static byte[] decode(byte[] source, int off, int len, int options)
Very low-level access to decoding ASCII characters in the form of a byte array.
static byte[] decode(String s, int options)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
static byte[] decode(String s)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
static boolean decodeFileToFile(String infile, String outfile)
Reads infile and decodes it to outfile.
static byte[] decodeFromFile(String filename)
Convenience method for reading a base64-encoded file and decoding it.
static boolean decodeToFile(String dataToDecode, String filename)
Convenience method for decoding data to a file.
static Object decodeToObject(String encodedObject)
Attempts to decode Base64 data and deserialize a Java Object within.
static String encodeBytes(byte[] source, int off, int len, int options)
Encodes a byte array into Base64 notation.
static String encodeBytes(byte[] source, int off, int len)
Encodes a byte array into Base64 notation.
static String encodeBytes(byte[] source, int options)
Encodes a byte array into Base64 notation.
static String encodeBytes(byte[] source)
Encodes a byte array into Base64 notation.
static boolean encodeFileToFile(String infile, String outfile)
Reads infile and encodes it to outfile.
static String encodeFromFile(String filename)
Convenience method for reading a binary file and base64-encoding it.
static String encodeFromStream(InputStream stream, int fileLength)
static String encodeObject(Serializable serializableObject, int options)
Serializes an object and returns the Base64-encoded version of that serialized object.
static String encodeObject(Serializable serializableObject)
Serializes an object and returns the Base64-encoded version of that serialized object.
static boolean encodeToFile(byte[] dataToEncode, String filename)
Convenience method for encoding data to a file.
[Expand]
Inherited Methods
From class java.lang.Object

Constants

public static final int DECODE

Specify decoding.

Constant Value: 0 (0x00000000)

public static final int DONT_BREAK_LINES

Don't break lines when encoding (violates strict Base64 specification)

Constant Value: 8 (0x00000008)

public static final int ENCODE

Specify encoding.

Constant Value: 1 (0x00000001)

public static final int GZIP

Specify that data should be gzip-compressed.

Constant Value: 2 (0x00000002)

public static final int NO_OPTIONS

No options specified. Value is zero.

Constant Value: 0 (0x00000000)

public static final int ORDERED

Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.

Constant Value: 32 (0x00000020)

public static final int URL_SAFE

Encode using Base64-like encoding that is URL- and Filename-safe as described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html. It is important to note that data encoded this way is not officially valid Base64, or at the very least should not be called Base64 without also specifying that is was encoded using the URL- and Filename-safe dialect.

Constant Value: 16 (0x00000010)

Public Methods

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

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.

Parameters
source The Base64 encoded data
off The offset of where to begin decoding
len The length of characters to decode
Returns
  • decoded data

public static byte[] decode (String s, int options)

Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.

Parameters
s the string to decode
options encode options such as URL_SAFE
Returns
  • the decoded data

public static byte[] decode (String s)

Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.

Parameters
s the string to decode
Returns
  • the decoded data

public static boolean decodeFileToFile (String infile, String outfile)

Reads infile and decodes it to outfile.

Parameters
infile Input file
outfile Output file
Returns
  • true if the operation is successful

public static byte[] decodeFromFile (String filename)

Convenience method for reading a base64-encoded file and decoding it.

Parameters
filename Filename for reading encoded data
Returns
  • decoded byte array or null if unsuccessful

public static boolean decodeToFile (String dataToDecode, String filename)

Convenience method for decoding data to a file.

Parameters
dataToDecode Base64-encoded data as a string
filename Filename for saving decoded data
Returns
  • true if successful, false otherwise

public static Object decodeToObject (String encodedObject)

Attempts to decode Base64 data and deserialize a Java Object within. Returns null if there was an error.

Parameters
encodedObject The Base64 data to decode
Returns
  • The decoded and deserialized object

public static String encodeBytes (byte[] source, int off, int len, int options)

Encodes a byte array into Base64 notation.

Valid options:

   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.
 

Example: encodeBytes( myData, Base64Harder.GZIP ) or

Example: encodeBytes( myData, Base64Harder.GZIP | Base64Harder.DONT_BREAK_LINES )

Parameters
source The data to convert
off Offset in array where conversion should begin
len Length of data to convert
options alphabet type is pulled from this (standard, url-safe, ordered)

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

Encodes a byte array into Base64 notation. Does not GZip-compress data.

Parameters
source The data to convert
off Offset in array where conversion should begin
len Length of data to convert

public static String encodeBytes (byte[] source, int options)

Encodes a byte array into Base64 notation.

Valid options:

   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.
 

Example: encodeBytes( myData, Base64Harder.GZIP ) or

Example: encodeBytes( myData, Base64Harder.GZIP | Base64Harder.DONT_BREAK_LINES )

Parameters
source The data to convert
options Specified options

public static String encodeBytes (byte[] source)

Encodes a byte array into Base64 notation. Does not GZip-compress data.

Parameters
source The data to convert

public static boolean encodeFileToFile (String infile, String outfile)

Reads infile and encodes it to outfile.

Parameters
infile Input file
outfile Output file
Returns
  • true if the operation is successful

public static String encodeFromFile (String filename)

Convenience method for reading a binary file and base64-encoding it.

Parameters
filename Filename for reading binary data
Returns
  • base64-encoded string or null if unsuccessful

public static String encodeFromStream (InputStream stream, int fileLength)

Throws
IOException

public static String encodeObject (Serializable serializableObject, int options)

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 null.

Valid options:

   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.
 

Example: encodeObject( myObj, Base64Harder.GZIP ) or

Example: encodeObject( myObj, Base64Harder.GZIP | Base64Harder#DONT_BREAK_LINES )

Parameters
serializableObject The object to encode
options Specified options
Returns
  • The Base64-encoded object

public static String encodeObject (Serializable serializableObject)

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 null. The object is not GZip-compressed before being encoded.

Parameters
serializableObject The object to encode
Returns
  • The Base64-encoded object

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

Convenience method for encoding data to a file.

Parameters
dataToEncode byte array of data to encode in base64 form
filename Filename for saving encoded data
Returns
  • true if successful, false otherwise