Encodes and decodes to and from Base64 notation.
Homepage: http://iharder.net/base64.
Example:
String encoded = Base64.encode( myByteArray );
byte[] myByteArray = Base64.decode( encoded );
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,
and encoding using the URL-safe and Ordered dialects.
Note, according to RFC3548,
Section 2.1, implementations should not add line feeds unless explicitly told
to do so. I've got Base64 set to this behavior now, although earlier versions
broke lines by default.
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.DO_BREAK_LINES );
to compress the data before encoding it and then making the output have newline characters.
Also...
String encoded = Base64.encodeBytes( crazyString.getBytes() );
Change Log:
- v2.3.7 - Fixed subtle bug when base 64 input stream contained the
value 01111111, which is an invalid base 64 character but should not
throw an ArrayIndexOutOfBoundsException either. Led to discovery of
mishandling (or potential for better handling) of other bad input
characters. You should now get an IOException if you try decoding
something that has bad characters in it.
- v2.3.6 - Fixed bug when breaking lines and the final byte of the encoded
string ended in the last column; the buffer was not properly shrunk and
contained an extra (null) byte that made it into the string.
- v2.3.5 - Fixed bug in
encodeFromFile(java.lang.String) where estimated buffer size
was wrong for files of size 31, 34, and 37 bytes.
- v2.3.4 - Fixed bug when working with gzipped streams whereby flushing
the Base64.OutputStream closed the Base64 encoding (by padding with equals
signs) too soon. Also added an option to suppress the automatic decoding
of gzipped streams. Also added experimental support for specifying a
class loader when using the
decodeToObject(java.lang.String, int, java.lang.ClassLoader)
method.
- v2.3.3 - Changed default char encoding to US-ASCII which reduces the internal Java
footprint with its CharEncoders and so forth. Fixed some javadocs that were
inconsistent. Removed imports and specified things like java.io.IOException
explicitly inline.
- v2.3.2 - Reduced memory footprint! Finally refined the "guessing" of how big the
final encoded data will be so that the code doesn't have to create two output
arrays: an oversized initial one and then a final, exact-sized one. Big win
when using the
encodeBytesToBytes(byte[]) family of methods (and not
using the gzip options which uses a different mechanism with streams and stuff).
- v2.3.1 - Added
encodeBytesToBytes(byte[], int, int, int) and some
similar helper methods to be more efficient with memory by not returning a
String but just a byte array.
- v2.3 - This is not a drop-in replacement! This is two years of comments
and bug fixes queued up and finally executed. Thanks to everyone who sent
me stuff, and I'm sorry I wasn't able to distribute your fixes to everyone else.
Much bad coding was cleaned up including throwing exceptions where necessary
instead of returning null values or something similar. Here are some changes
that may affect you:
- Does not break lines, by default. This is to keep in compliance with
RFC3548.
- Throws exceptions instead of returning null values. Because some operations
(especially those that may permit the GZIP option) use IO streams, there
is a possiblity of an java.io.IOException being thrown. After some discussion and
thought, I've changed the behavior of the methods to throw java.io.IOExceptions
rather than return null if ever there's an error. I think this is more
appropriate, though it will require some changes to your code. Sorry,
it should have been done this way to begin with.
- Removed all references to System.out, System.err, and the like.
Shame on me. All I can say is sorry they were ever there.
- Throws NullPointerExceptions and IllegalArgumentExceptions as needed
such as when passed arrays are null or offsets are invalid.
- Cleaned up as much javadoc as I could to avoid any javadoc warnings.
This was especially annoying before for people who were thorough in their
own projects and then had gobs of javadoc warnings on this file.
- 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:
- The default is RFC3548 format.
- 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
- 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.