Class Base64
This code is a stripped down version of Robert Harder's Public Domain Base64 implementation. GZIP support, InputStream and OutputStream stuff and some unneeded encode/decode methods have been removed.
-- Original comments follow --
Encodes and decodes to and from Base64 notation.
Change Log:
- 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 (
int
s 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.
- Version:
- 2.1
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate static final byte[]
private static final byte[]
The 64 valid Base64 values.private static final byte[]
Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.static final int
Specify decoding.static final int
Don't break lines when encoding (violates strict Base64 specification).static final int
Specify encoding.private static final byte
The equals sign (=) as a byte.private static final byte
private static final int
Maximum line length (76) of Base64 output.private static final byte
The new line character (\n) as a byte.static final int
No options specified.private static final String
Preferred encoding.private static final byte
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic byte[]
decode
(byte[] source, int off, int len) Very low-level access to decoding ASCII characters in the form of a byte array.static byte[]
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.private static int
decode4to3
(byte[] source, int srcOffset, byte[] destination, int destOffset) Decodes four bytes from array source and writes the resulting bytes (up to three of them) to destination.private static byte[]
encode3to4
(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset) Encodes up to three bytes of the array source and writes the resulting four Base64 bytes to destination.static String
encodeBytes
(byte[] source) 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, int off, int len) Encodes a byte array into Base64 notation.static String
encodeBytes
(byte[] source, int off, int len, int options) Encodes a byte array into Base64 notation.
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Field Details
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NO_OPTIONS
public static final int NO_OPTIONSNo options specified. Value is zero.- See Also:
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ENCODE
public static final int ENCODESpecify encoding.- See Also:
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DECODE
public static final int DECODESpecify decoding.- See Also:
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DONT_BREAK_LINES
public static final int DONT_BREAK_LINESDon't break lines when encoding (violates strict Base64 specification).- See Also:
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MAX_LINE_LENGTH
private static final int MAX_LINE_LENGTHMaximum line length (76) of Base64 output.- See Also:
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EQUALS_SIGN
private static final byte EQUALS_SIGNThe equals sign (=) as a byte.- See Also:
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NEW_LINE
private static final byte NEW_LINEThe new line character (\n) as a byte.- See Also:
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PREFERRED_ENCODING
Preferred encoding.- See Also:
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ALPHABET
private static final byte[] ALPHABETThe 64 valid Base64 values. -
_NATIVE_ALPHABET
private static final byte[] _NATIVE_ALPHABET -
DECODABET
private static final byte[] DECODABETTranslates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning. -
WHITE_SPACE_ENC
private static final byte WHITE_SPACE_ENC- See Also:
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EQUALS_SIGN_ENC
private static final byte EQUALS_SIGN_ENC- See Also:
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Constructor Details
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Base64
private Base64()Defeats instantiation.
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Method Details
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encode3to4
private static byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset) Encodes up to three bytes of the array source and writes the resulting four Base64 bytes to destination. The source and destination arrays can be manipulated anywhere along their length by specifying srcOffset and destOffset. This method does not check to make sure your arrays are large enough to accommodate srcOffset + 3 for the source array or destOffset + 4 for the destination array. The actual number of significant bytes in your array is given by numSigBytes.- Parameters:
source
- the array to convertsrcOffset
- the index where conversion beginsnumSigBytes
- the number of significant bytes in your arraydestination
- the array to hold the conversiondestOffset
- the index where output will be put- Returns:
- the destination array
- Since:
- 1.3
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encodeBytes
Encodes a byte array into Base64 notation. Does not GZip-compress data.- Parameters:
source
- The data to convert- Returns:
- Base64 notation of input data
- Since:
- 1.4
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encodeBytes
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, Base64.GZIP )
orExample:
encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )
- Parameters:
source
- The data to convertoptions
- Specified options- Returns:
- Base64 notation
- Since:
- 2.0
- See Also:
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encodeBytes
Encodes a byte array into Base64 notation. Does not GZip-compress data.- Parameters:
source
- The data to convertoff
- Offset in array where conversion should beginlen
- Length of data to convert- Returns:
- Base64 notation
- Since:
- 1.4
-
encodeBytes
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, Base64.GZIP )
orExample:
encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )
- Parameters:
source
- The data to convertoff
- Offset in array where conversion should beginlen
- Length of data to convertoptions
- Specified options- Returns:
- Base64 notation
- Since:
- 2.0
- See Also:
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decode4to3
private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset) Decodes four bytes from array source and writes the resulting bytes (up to three of them) to destination. The source and destination arrays can be manipulated anywhere along their length by specifying srcOffset and destOffset. This method does not check to make sure your arrays are large enough to accommodate srcOffset + 4 for the source array or destOffset + 3 for the destination array. This method returns the actual number of bytes that were converted from the Base64 encoding.- Parameters:
source
- the array to convertsrcOffset
- the index where conversion beginsdestination
- the array to hold the conversiondestOffset
- the index where output will be put- Returns:
- the number of decoded bytes converted
- Since:
- 1.3
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decode
public static byte[] decode(byte[] source, int off, int len) 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 dataoff
- The offset of where to begin decodinglen
- The length of characters to decode- Returns:
- decoded data
- Since:
- 1.3
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decode
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.- Parameters:
s
- the string to decode- Returns:
- the decoded data
- Since:
- 1.4
-