org.openadaptor.util.base64
Class Base64

java.lang.Object
  org.openadaptor.util.base64.Base64

public class Base64
extends java.lang.Object

Helper class for encoding byte arrays into base64 Strings and vice-versa. Base64 is the MIME / RFC1521 standard for turning binary byte streams into meaningless "printable" (i.e. a-z A-Z 0-9 etc.) strings for safe shipping around by text-based utilities.

Field Summary

(package private) static java.lang.StringBuffer	encoded
static int	INVALID_CHAR Magic number representing the invalid chars when decoding base64.
static int	PAD_CHAR Magic number representing the padding char when decoding base64.
static int	WHITESPACE_CHAR Magic number representing the whitespace chars when decoding base64.

Constructor Summary

Base64()

Method Summary

(package private) static boolean	compareByteArrays(byte[] a1, byte[] a2)
static byte[]	decode(java.lang.String base64) Decodes a Base64 String into a byte array.
static java.lang.String	encode(byte[] raw) Encodes a byte array as a Base64 String.
static java.lang.String	encode(byte[] raw, int maxLineLength) Encodes a byte array as a Base64 String with line breaks.
protected static char[]	encodeBlock(byte[] raw, int offset) Encodes three characters at offset + [0,1,2] in raw into base64 characters.
protected static char	getChar(int sixBit) Given a six bit value, returns the corresponding base64 character
protected static int	getValue(char c) Decodes a single Base64 charater, and returns it as a six bit value.
static void	main(java.lang.String[] args)

Methods inherited from class java.lang.Object

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

Field Detail

PAD_CHAR

public static final int PAD_CHAR

Magic number representing the padding char when decoding base64.

See Also:

Constant Field Values

WHITESPACE_CHAR

public static final int WHITESPACE_CHAR

Magic number representing the whitespace chars when decoding base64.

See Also:

Constant Field Values

INVALID_CHAR

public static final int INVALID_CHAR

Magic number representing the invalid chars when decoding base64.

See Also:

Constant Field Values

encoded

static java.lang.StringBuffer encoded

Constructor Detail

Base64

public Base64()

Method Detail

encode

public static java.lang.String encode(byte[] raw)

Encodes a byte array as a Base64 String. The string is encoded with no line breaks, so cannot be handled easily by text editors etc.

Parameters:

raw - Byte Array to be encoded.

Returns:

Byte64 encoded String representation of raw

encode

public static java.lang.String encode(byte[] raw,
                                      int maxLineLength)

Encodes a byte array as a Base64 String with line breaks. The user must pass a maximum line length, which should be a multiple of 4 characters (if not it will be rounded up). The String returned will have have line breaks ('\n') at or before the maximum line length. In addition, a linebreak will be added at the end of the message. This whitespace will be ignored by decoders. A line length of zero or less means no line breaks.

Parameters:

raw - Byte Array to be encoded.

lineLength - maximum length of line.

Returns:

Byte64 encoded String representation of raw

encodeBlock

protected static char[] encodeBlock(byte[] raw,
                                    int offset)

Encodes three characters at offset + [0,1,2] in raw into base64 characters. Note this is ripe for optimisation!

getChar

protected static char getChar(int sixBit)

Given a six bit value, returns the corresponding base64 character

Parameters:

sixBit - Six bit integer value.

Returns:

Corresponding base64 character, or '?' for a number outside 0..63.

decode

public static byte[] decode(java.lang.String base64)
                     throws Base64Exception

Decodes a Base64 String into a byte array. Note that is can handle embedded whitespace i.e. linebreaks. Note this is ripe for optimisation!

Parameters:

base64 - Base64 String to be decoded.

Returns:

Decoded byte Array containing bytes in the original message.

Throws:

Base64Exception - If base64 contains an invalid base64 message, i.e. illegal charaters, too many padding chars etc.

getValue

protected static int getValue(char c)

Decodes a single Base64 charater, and returns it as a six bit value.

Returns:

Six bit value of char c or PAD_CHAR, WHITESPACE_CHAR or INVALID_CHAR.

main

public static void main(java.lang.String[] args)

compareByteArrays

static boolean compareByteArrays(byte[] a1,
                                 byte[] a2)