Class Base64
- java.lang.Object
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- com.itextpdf.text.pdf.codec.Base64
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public class Base64 extends java.lang.Object
Encodes and decodes to and from Base64 notation.
Homepage: http://iharder.net/base64.
Change Log:
- 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
- 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.
- Version:
- 2.2.1
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
Base64.InputStream
ABase64.InputStream
will read data from another java.io.InputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly.static class
Base64.OutputStream
ABase64.OutputStream
will write data to another java.io.OutputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly.
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Field Summary
Fields Modifier and Type Field Description private static byte[]
_ORDERED_ALPHABET
I don't get the point of this technique, but it is described here: http://www.faqs.org/qa/rfcc-1940.html.private static byte[]
_ORDERED_DECODABET
Used in decoding the "ordered" dialect of Base64.private static byte[]
_STANDARD_ALPHABET
The 64 valid Base64 values.private static byte[]
_STANDARD_DECODABET
Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.private static byte[]
_URL_SAFE_ALPHABET
Used in the URL- and Filename-safe dialect described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html.private static byte[]
_URL_SAFE_DECODABET
Used in decoding URL- and Filename-safe dialects of Base64.static int
DECODE
Specify decoding.static int
DONT_BREAK_LINES
Don't break lines when encoding (violates strict Base64 specification)static int
ENCODE
Specify encoding.private static byte
EQUALS_SIGN
The equals sign (=) as a byte.private static byte
EQUALS_SIGN_ENC
static int
GZIP
Specify that data should be gzip-compressed.private static int
MAX_LINE_LENGTH
Maximum line length (76) of Base64 output.private static byte
NEW_LINE
The new line character (\n) as a byte.static int
NO_OPTIONS
No options specified.static int
ORDERED
Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.private static java.lang.String
PREFERRED_ENCODING
Preferred encoding.static 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.private static byte
WHITE_SPACE_ENC
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Constructor Summary
Constructors Modifier Constructor Description private
Base64()
Defeats instantiation.
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description 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(java.lang.String s)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.static byte[]
decode(java.lang.String s, int options)
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, int options)
Decodes four bytes from array source and writes the resulting bytes (up to three of them) to destination.static void
decodeFileToFile(java.lang.String infile, java.lang.String outfile)
Reads infile and decodes it to outfile.static byte[]
decodeFromFile(java.lang.String filename)
Convenience method for reading a base64-encoded file and decoding it.static boolean
decodeToFile(java.lang.String dataToDecode, java.lang.String filename)
Convenience method for decoding data to a file.static java.lang.Object
decodeToObject(java.lang.String encodedObject)
Attempts to decode Base64 data and deserialize a Java Object within.private static byte[]
encode3to4(byte[] b4, byte[] threeBytes, int numSigBytes, int options)
Encodes up to the first three bytes of array threeBytes and returns a four-byte array in Base64 notation.private static byte[]
encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset, int options)
Encodes up to three bytes of the array source and writes the resulting four Base64 bytes to destination.static java.lang.String
encodeBytes(byte[] source)
Encodes a byte array into Base64 notation.static java.lang.String
encodeBytes(byte[] source, int options)
Encodes a byte array into Base64 notation.static java.lang.String
encodeBytes(byte[] source, int off, int len)
Encodes a byte array into Base64 notation.static java.lang.String
encodeBytes(byte[] source, int off, int len, int options)
Encodes a byte array into Base64 notation.static void
encodeFileToFile(java.lang.String infile, java.lang.String outfile)
Reads infile and encodes it to outfile.static java.lang.String
encodeFromFile(java.lang.String filename)
Convenience method for reading a binary file and base64-encoding it.static java.lang.String
encodeObject(java.io.Serializable serializableObject)
Serializes an object and returns the Base64-encoded version of that serialized object.static java.lang.String
encodeObject(java.io.Serializable serializableObject, int options)
Serializes an object and returns the Base64-encoded version of that serialized object.static boolean
encodeToFile(byte[] dataToEncode, java.lang.String filename)
Convenience method for encoding data to a file.private static byte[]
getAlphabet(int options)
Returns one of the _SOMETHING_ALPHABET byte arrays depending on the options specified.private static byte[]
getDecodabet(int options)
Returns one of the _SOMETHING_DECODABET byte arrays depending on the options specified.private static void
usage(java.lang.String msg)
Prints command line usage.
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Field Detail
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NO_OPTIONS
public static final int NO_OPTIONS
No options specified. Value is zero.- See Also:
- Constant Field Values
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ENCODE
public static final int ENCODE
Specify encoding.- See Also:
- Constant Field Values
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DECODE
public static final int DECODE
Specify decoding.- See Also:
- Constant Field Values
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GZIP
public static final int GZIP
Specify that data should be gzip-compressed.- See Also:
- Constant Field Values
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DONT_BREAK_LINES
public static final int DONT_BREAK_LINES
Don't break lines when encoding (violates strict Base64 specification)- See Also:
- Constant Field Values
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URL_SAFE
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.- See Also:
- Constant Field Values
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ORDERED
public static final int ORDERED
Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.- See Also:
- Constant Field Values
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MAX_LINE_LENGTH
private static final int MAX_LINE_LENGTH
Maximum line length (76) of Base64 output.- See Also:
- Constant Field Values
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EQUALS_SIGN
private static final byte EQUALS_SIGN
The equals sign (=) as a byte.- See Also:
- Constant Field Values
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NEW_LINE
private static final byte NEW_LINE
The new line character (\n) as a byte.- See Also:
- Constant Field Values
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PREFERRED_ENCODING
private static final java.lang.String PREFERRED_ENCODING
Preferred encoding.- See Also:
- Constant Field Values
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WHITE_SPACE_ENC
private static final byte WHITE_SPACE_ENC
- See Also:
- Constant Field Values
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EQUALS_SIGN_ENC
private static final byte EQUALS_SIGN_ENC
- See Also:
- Constant Field Values
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_STANDARD_ALPHABET
private static final byte[] _STANDARD_ALPHABET
The 64 valid Base64 values.
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_STANDARD_DECODABET
private static final byte[] _STANDARD_DECODABET
Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.
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_URL_SAFE_ALPHABET
private static final byte[] _URL_SAFE_ALPHABET
Used in the URL- and Filename-safe dialect described in Section 4 of RFC3548: http://www.faqs.org/rfcs/rfc3548.html. Notice that the last two bytes become "hyphen" and "underscore" instead of "plus" and "slash."
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_URL_SAFE_DECODABET
private static final byte[] _URL_SAFE_DECODABET
Used in decoding URL- and Filename-safe dialects of Base64.
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_ORDERED_ALPHABET
private static final byte[] _ORDERED_ALPHABET
I don't get the point of this technique, but it is described here: http://www.faqs.org/qa/rfcc-1940.html.
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_ORDERED_DECODABET
private static final byte[] _ORDERED_DECODABET
Used in decoding the "ordered" dialect of Base64.
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Method Detail
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getAlphabet
private static final byte[] getAlphabet(int options)
Returns one of the _SOMETHING_ALPHABET byte arrays depending on the options specified. It's possible, though silly, to specify ORDERED and URLSAFE in which case one of them will be picked, though there is no guarantee as to which one will be picked.
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getDecodabet
private static final byte[] getDecodabet(int options)
Returns one of the _SOMETHING_DECODABET byte arrays depending on the options specified. It's possible, though silly, to specify ORDERED and URL_SAFE in which case one of them will be picked, though there is no guarantee as to which one will be picked.
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usage
private static final void usage(java.lang.String msg)
Prints command line usage.- Parameters:
msg
- A message to include with usage info.
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encode3to4
private static byte[] encode3to4(byte[] b4, byte[] threeBytes, int numSigBytes, int options)
Encodes up to the first three bytes of array threeBytes and returns a four-byte array in Base64 notation. The actual number of significant bytes in your array is given by numSigBytes. The array threeBytes needs only be as big as numSigBytes. Code can reuse a byte array by passing a four-byte array as b4.- Parameters:
b4
- A reusable byte array to reduce array instantiationthreeBytes
- the array to convertnumSigBytes
- the number of significant bytes in your array- Returns:
- four byte array in Base64 notation.
- Since:
- 1.5.1
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encode3to4
private static byte[] encode3to4(byte[] source, int srcOffset, int numSigBytes, byte[] destination, int destOffset, int options)
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 accomodate 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.
This is the lowest level of the encoding methods with all possible parameters.
- 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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encodeObject
public static java.lang.String encodeObject(java.io.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
- Since:
- 1.4
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encodeObject
public static java.lang.String encodeObject(java.io.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, Base64.GZIP )
orExample:
encodeObject( myObj, Base64.GZIP | Base64.DONT_BREAK_LINES )
- Parameters:
serializableObject
- The object to encodeoptions
- Specified options- Returns:
- The Base64-encoded object
- Since:
- 2.0
- See Also:
GZIP
,DONT_BREAK_LINES
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encodeBytes
public static java.lang.String encodeBytes(byte[] source)
Encodes a byte array into Base64 notation. Does not GZip-compress data.- Parameters:
source
- The data to convert- Since:
- 1.4
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encodeBytes
public static java.lang.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, Base64.GZIP )
orExample:
encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )
- Parameters:
source
- The data to convertoptions
- Specified options- Since:
- 2.0
- See Also:
GZIP
,DONT_BREAK_LINES
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encodeBytes
public static java.lang.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 convertoff
- Offset in array where conversion should beginlen
- Length of data to convert- Since:
- 1.4
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encodeBytes
public static java.lang.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, 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 alphabet type is pulled from this (standard, url-safe, ordered)- Since:
- 2.0
- See Also:
GZIP
,DONT_BREAK_LINES
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decode4to3
private static int decode4to3(byte[] source, int srcOffset, byte[] destination, int destOffset, int options)
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 accomodate 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.This is the lowest level of the decoding methods with all possible parameters.
- Parameters:
source
- the array to convertsrcOffset
- the index where conversion beginsdestination
- the array to hold the conversiondestOffset
- the index where output will be putoptions
- alphabet type is pulled from this (standard, url-safe, ordered)- 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, 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 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
public static byte[] decode(java.lang.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
- Since:
- 1.4
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decode
public static byte[] decode(java.lang.String s, int options)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.- Parameters:
s
- the string to decodeoptions
- encode options such as URL_SAFE- Returns:
- the decoded data
- Since:
- 1.4
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decodeToObject
public static java.lang.Object decodeToObject(java.lang.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
- Since:
- 1.5
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encodeToFile
public static boolean encodeToFile(byte[] dataToEncode, java.lang.String filename)
Convenience method for encoding data to a file.- Parameters:
dataToEncode
- byte array of data to encode in base64 formfilename
- Filename for saving encoded data- Returns:
- true if successful, false otherwise
- Since:
- 2.1
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decodeToFile
public static boolean decodeToFile(java.lang.String dataToDecode, java.lang.String filename)
Convenience method for decoding data to a file.- Parameters:
dataToDecode
- Base64-encoded data as a stringfilename
- Filename for saving decoded data- Returns:
- true if successful, false otherwise
- Since:
- 2.1
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decodeFromFile
public static byte[] decodeFromFile(java.lang.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
- Since:
- 2.1
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encodeFromFile
public static java.lang.String encodeFromFile(java.lang.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
- Since:
- 2.1
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encodeFileToFile
public static void encodeFileToFile(java.lang.String infile, java.lang.String outfile)
Reads infile and encodes it to outfile.- Parameters:
infile
- Input fileoutfile
- Output file- Since:
- 2.2
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decodeFileToFile
public static void decodeFileToFile(java.lang.String infile, java.lang.String outfile)
Reads infile and decodes it to outfile.- Parameters:
infile
- Input fileoutfile
- Output file- Since:
- 2.2
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