com.lowagie.text.pdf.codec

Class Base64

public class Base64 extends Object

Encodes and decodes to and from Base64 notation.

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

Change Log:

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

Author: Robert Harder rob@iharder.net

Nested Class Summary
static classBase64.InputStream
A InputStream will read data from another java.io.InputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly.
static classBase64.OutputStream
A OutputStream will write data to another java.io.OutputStream, given in the constructor, and encode/decode to/from Base64 notation on the fly.
Field Summary
static intDECODE
Specify decoding.
static intDONT_BREAK_LINES
Don't break lines when encoding (violates strict Base64 specification)
static intENCODE
Specify encoding.
static byteEQUALS_SIGN
The equals sign (=) as a byte.
static byteEQUALS_SIGN_ENC
static intGZIP
Specify that data should be gzip-compressed.
static intMAX_LINE_LENGTH
Maximum line length (76) of Base64 output.
static byteNEW_LINE
The new line character (\n) as a byte.
static intNO_OPTIONS
No options specified.
static intORDERED
Encode using the special "ordered" dialect of Base64 described here: http://www.faqs.org/qa/rfcc-1940.html.
static StringPREFERRED_ENCODING
Preferred encoding.
static intURL_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.
static byteWHITE_SPACE_ENC
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.
static byte[]_ORDERED_DECODABET
Used in decoding the "ordered" dialect of Base64.
static byte[]_STANDARD_ALPHABET
The 64 valid Base64 values.
static byte[]_STANDARD_DECODABET
Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.
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.
static byte[]_URL_SAFE_DECODABET
Used in decoding URL- and Filename-safe dialects of Base64.
Constructor Summary
Base64()
Defeats instantiation.
Method Summary
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)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
static byte[]decode(String s, int options)
Decodes data from Base64 notation, automatically detecting gzip-compressed data and decompressing it.
static intdecode4to3(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 voiddecodeFileToFile(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 booleandecodeToFile(String dataToDecode, String filename)
Convenience method for decoding data to a file.
static ObjectdecodeToObject(String encodedObject)
Attempts to decode Base64 data and deserialize a Java Object within.
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.
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 StringencodeBytes(byte[] source)
Encodes a byte array into Base64 notation.
static StringencodeBytes(byte[] source, int options)
Encodes a byte array into Base64 notation.
static StringencodeBytes(byte[] source, int off, int len)
Encodes a byte array into Base64 notation.
static StringencodeBytes(byte[] source, int off, int len, int options)
Encodes a byte array into Base64 notation.
static voidencodeFileToFile(String infile, String outfile)
Reads infile and encodes it to outfile.
static StringencodeFromFile(String filename)
Convenience method for reading a binary file and base64-encoding it.
static StringencodeObject(Serializable serializableObject)
Serializes an object and returns the Base64-encoded version of that serialized object.
static StringencodeObject(Serializable serializableObject, int options)
Serializes an object and returns the Base64-encoded version of that serialized object.
static booleanencodeToFile(byte[] dataToEncode, String filename)
Convenience method for encoding data to a file.
static byte[]getAlphabet(int options)
Returns one of the _SOMETHING_ALPHABET byte arrays depending on the options specified.
static byte[]getDecodabet(int options)
Returns one of the _SOMETHING_DECODABET byte arrays depending on the options specified.
static voidmain(String[] args)
Encodes or decodes two files from the command line; feel free to delete this method (in fact you probably should) if you're embedding this code into a larger program.
static voidusage(String msg)
Prints command line usage.

Field Detail

DECODE

public static final int DECODE
Specify decoding.

DONT_BREAK_LINES

public static final int DONT_BREAK_LINES
Don't break lines when encoding (violates strict Base64 specification)

ENCODE

public static final int ENCODE
Specify encoding.

EQUALS_SIGN

private static final byte EQUALS_SIGN
The equals sign (=) as a byte.

EQUALS_SIGN_ENC

private static final byte EQUALS_SIGN_ENC

GZIP

public static final int GZIP
Specify that data should be gzip-compressed.

MAX_LINE_LENGTH

private static final int MAX_LINE_LENGTH
Maximum line length (76) of Base64 output.

NEW_LINE

private static final byte NEW_LINE
The new line character (\n) as a byte.

NO_OPTIONS

public static final int NO_OPTIONS
No options specified. Value is zero.

ORDERED

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

PREFERRED_ENCODING

private static final String PREFERRED_ENCODING
Preferred encoding.

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.

WHITE_SPACE_ENC

private static final byte WHITE_SPACE_ENC

_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.

_ORDERED_DECODABET

private static final byte[] _ORDERED_DECODABET
Used in decoding the "ordered" dialect of Base64.

_STANDARD_ALPHABET

private static final byte[] _STANDARD_ALPHABET
The 64 valid Base64 values.

_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.

_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."

_URL_SAFE_DECODABET

private static final byte[] _URL_SAFE_DECODABET
Used in decoding URL- and Filename-safe dialects of Base64.

Constructor Detail

Base64

private Base64()
Defeats instantiation.

Method Detail

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 data off The offset of where to begin decoding len The length of characters to decode

Returns: decoded data

Since: 1.3

decode

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

Since: 1.4

decode

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

Since: 1.4

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 convert srcOffset the index where conversion begins destination the array to hold the conversion destOffset the index where output will be put options alphabet type is pulled from this (standard, url-safe, ordered)

Returns: the number of decoded bytes converted

Since: 1.3

decodeFileToFile

public static void decodeFileToFile(String infile, String outfile)
Reads infile and decodes it to outfile.

Parameters: infile Input file outfile Output file

Since: 2.2

decodeFromFile

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

Since: 2.1

decodeToFile

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

Since: 2.1

decodeToObject

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

Since: 1.5

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 instantiation threeBytes the array to convert numSigBytes the number of significant bytes in your array

Returns: four byte array in Base64 notation.

Since: 1.5.1

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 convert srcOffset the index where conversion begins numSigBytes the number of significant bytes in your array destination the array to hold the conversion destOffset the index where output will be put

Returns: the destination array

Since: 1.3

encodeBytes

public static 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

encodeBytes

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, Base64.GZIP ) or

Example: encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )

Parameters: source The data to convert options Specified options

Since: 2.0

See Also: GZIP DONT_BREAK_LINES

encodeBytes

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

Since: 1.4

encodeBytes

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, Base64.GZIP ) or

Example: encodeBytes( myData, Base64.GZIP | Base64.DONT_BREAK_LINES )

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

Since: 2.0

See Also: GZIP DONT_BREAK_LINES

encodeFileToFile

public static void encodeFileToFile(String infile, String outfile)
Reads infile and encodes it to outfile.

Parameters: infile Input file outfile Output file

Since: 2.2

encodeFromFile

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

Since: 2.1

encodeObject

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

Since: 1.4

encodeObject

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, Base64.GZIP ) or

Example: encodeObject( myObj, Base64.GZIP | Base64.DONT_BREAK_LINES )

Parameters: serializableObject The object to encode options Specified options

Returns: The Base64-encoded object

Since: 2.0

See Also: GZIP DONT_BREAK_LINES

encodeToFile

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

Since: 2.1

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.

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.

main

public static final void main(String[] args)
Encodes or decodes two files from the command line; feel free to delete this method (in fact you probably should) if you're embedding this code into a larger program.

usage

private static final void usage(String msg)
Prints command line usage.

Parameters: msg A message to include with usage info.