org.apache.commons.codec.binary
Class Base64

java.lang.Object
  org.apache.commons.codec.binary.Base64

All Implemented Interfaces:

BinaryDecoder, BinaryEncoder, Decoder, Encoder

public class Base64

extends Object

implements BinaryEncoder, BinaryDecoder

Provides Base64 encoding and decoding as defined by RFC 2045.

This class implements section 6.8. Base64 Content-Transfer-Encoding from RFC 2045 Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies by Freed and Borenstein.

Since:

1.0-dev

Version:

$Id: Base64.java,v 1.20 2004/05/24 00:21:24 ggregory Exp $

Author:

Apache Software Foundation

See Also:

RFC 2045

Field Summary

private static byte[]	base64Alphabet
(package private) static int	BASELENGTH The base length.
(package private) static byte[]	CHUNK_SEPARATOR Chunk separator per RFC 2045 section 2.1.
(package private) static int	CHUNK_SIZE Chunk size per RFC 2045 section 6.8.
(package private) static int	EIGHTBIT Used to calculate the number of bits in a byte.
(package private) static int	FOURBYTE Used to get the number of Quadruples.
private static byte[]	lookUpBase64Alphabet
(package private) static int	LOOKUPLENGTH Lookup length.
(package private) static byte	PAD Byte used to pad output.
(package private) static int	SIGN Used to test the sign of a byte.
(package private) static int	SIXTEENBIT Used when encoding something which has fewer than 24 bits.
(package private) static int	TWENTYFOURBITGROUP Used to determine how many bits data contains.

Constructor Summary

Base64()

Method Summary

byte[]	decode(byte[] pArray) Decodes a byte[] containing containing characters in the Base64 alphabet.
Object	decode(Object pObject) Decodes an Object using the base64 algorithm.
static byte[]	decodeBase64(byte[] base64Data) Decodes Base64 data into octects
(package private) static byte[]	discardNonBase64(byte[] data) Discards any characters outside of the base64 alphabet, per the requirements on page 25 of RFC 2045 - "Any characters outside of the base64 alphabet are to be ignored in base64 encoded data."
(package private) static byte[]	discardWhitespace(byte[] data) Discards any whitespace from a base-64 encoded block.
byte[]	encode(byte[] pArray) Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.
Object	encode(Object pObject) Encodes an Object using the base64 algorithm.
static byte[]	encodeBase64(byte[] binaryData) Encodes binary data using the base64 algorithm but does not chunk the output.
static byte[]	encodeBase64(byte[] binaryData, boolean isChunked) Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.
static byte[]	encodeBase64Chunked(byte[] binaryData) Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks
static boolean	isArrayByteBase64(byte[] arrayOctect) Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.
private static boolean	isBase64(byte octect)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CHUNK_SIZE

static final int CHUNK_SIZE

Chunk size per RFC 2045 section 6.8.

The 76 character limit does not count the trailing CRLF, but counts all other characters, including any equal signs.

See Also:

RFC 2045 section 6.8, Constant Field Values

CHUNK_SEPARATOR

static final byte[] CHUNK_SEPARATOR

Chunk separator per RFC 2045 section 2.1.

See Also:

RFC 2045 section 2.1

BASELENGTH

static final int BASELENGTH

The base length.

See Also:

Constant Field Values

LOOKUPLENGTH

static final int LOOKUPLENGTH

Lookup length.

See Also:

Constant Field Values

EIGHTBIT

static final int EIGHTBIT

Used to calculate the number of bits in a byte.

See Also:

Constant Field Values

SIXTEENBIT

static final int SIXTEENBIT

Used when encoding something which has fewer than 24 bits.

See Also:

Constant Field Values

TWENTYFOURBITGROUP

static final int TWENTYFOURBITGROUP

Used to determine how many bits data contains.

See Also:

Constant Field Values

FOURBYTE

static final int FOURBYTE

Used to get the number of Quadruples.

See Also:

Constant Field Values

SIGN

static final int SIGN

Used to test the sign of a byte.

See Also:

Constant Field Values

PAD

static final byte PAD

Byte used to pad output.

See Also:

Constant Field Values

base64Alphabet

private static byte[] base64Alphabet

lookUpBase64Alphabet

private static byte[] lookUpBase64Alphabet

Constructor Detail

Base64

public Base64()

Method Detail

isBase64

private static boolean isBase64(byte octect)

isArrayByteBase64

public static boolean isArrayByteBase64(byte[] arrayOctect)

Tests a given byte array to see if it contains only valid characters within the Base64 alphabet.

Parameters:

arrayOctect - byte array to test

Returns:

true if all bytes are valid characters in the Base64 alphabet or if the byte array is empty; false, otherwise

encodeBase64

public static byte[] encodeBase64(byte[] binaryData)

Encodes binary data using the base64 algorithm but does not chunk the output.

Parameters:

binaryData - binary data to encode

Returns:

Base64 characters

encodeBase64Chunked

public static byte[] encodeBase64Chunked(byte[] binaryData)

Encodes binary data using the base64 algorithm and chunks the encoded output into 76 character blocks

Parameters:

binaryData - binary data to encode

Returns:

Base64 characters chunked in 76 character blocks

decode

public Object decode(Object pObject)
              throws DecoderException

Decodes an Object using the base64 algorithm. This method is provided in order to satisfy the requirements of the Decoder interface, and will throw a DecoderException if the supplied object is not of type byte[].

Specified by:

decode in interface Decoder

Parameters:

pObject - Object to decode

Returns:

An object (of type byte[]) containing the binary data which corresponds to the byte[] supplied.

Throws:

DecoderException - if the parameter supplied is not of type byte[]

decode

public byte[] decode(byte[] pArray)

Decodes a byte[] containing containing characters in the Base64 alphabet.

Specified by:

decode in interface BinaryDecoder

Parameters:

pArray - A byte array containing Base64 character data

Returns:

a byte array containing binary data

encodeBase64

public static byte[] encodeBase64(byte[] binaryData,
                                  boolean isChunked)

Encodes binary data using the base64 algorithm, optionally chunking the output into 76 character blocks.

Parameters:

binaryData - Array containing binary data to encode.

isChunked - if isChunked is true this encoder will chunk the base64 output into 76 character blocks

Returns:

Base64-encoded data.

decodeBase64

public static byte[] decodeBase64(byte[] base64Data)

Decodes Base64 data into octects

Parameters:

base64Data - Byte array containing Base64 data

Returns:

Array containing decoded data.

discardWhitespace

static byte[] discardWhitespace(byte[] data)

Discards any whitespace from a base-64 encoded block.

Parameters:

data - The base-64 encoded data to discard the whitespace from.

Returns:

The data, less whitespace (see RFC 2045).

discardNonBase64

static byte[] discardNonBase64(byte[] data)

Discards any characters outside of the base64 alphabet, per the requirements on page 25 of RFC 2045 - "Any characters outside of the base64 alphabet are to be ignored in base64 encoded data."

Parameters:

data - The base-64 encoded data to groom

Returns:

The data, less non-base64 characters (see RFC 2045).

encode

public Object encode(Object pObject)
              throws EncoderException

Encodes an Object using the base64 algorithm. This method is provided in order to satisfy the requirements of the Encoder interface, and will throw an EncoderException if the supplied object is not of type byte[].

Specified by:

encode in interface Encoder

Parameters:

pObject - Object to encode

Returns:

An object (of type byte[]) containing the base64 encoded data which corresponds to the byte[] supplied.

Throws:

EncoderException - if the parameter supplied is not of type byte[]

encode

public byte[] encode(byte[] pArray)

Encodes a byte[] containing binary data, into a byte[] containing characters in the Base64 alphabet.

Specified by:

encode in interface BinaryEncoder

Parameters:

pArray - a byte array containing binary data

Returns:

A byte array containing only Base64 character data