anon.util
Class Base64

java.lang.Object
  anon.util.Base64

public class Base64
extends java.lang.Object

Encodes and decodes to and from Base64 notation.

Change Log:

• 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/xmlizable periodically to check for updates or to contribute improvements.

Version:

1.4

Author:

Robert Harder, rob@iharder.net

Field Summary

private static byte[]	ALPHABET The 64 valid Base64 values.
static java.lang.String	BEGIN_TAG
static boolean	COMPRESS Specify that data should be compressed (value is true).
private static byte[]	DECODABET Translates a Base64 value to either its 6-bit reconstruction value or a negative number indicating some other meaning.
static boolean	DECODE Specify decoding (value is false).
static boolean	DONT_COMPRESS Specify that data should not be compressed (value is false).
static boolean	ENCODE Specify encoding (value is true).
static java.lang.String	END_TAG
private static byte	EQUALS_SIGN The equals sign (=) as a byte.
private static byte	EQUALS_SIGN_ENC
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 java.lang.String	TAG_END_SEQUENCE
private static byte	WHITE_SPACE_ENC

Constructor Summary

private

Base64() Defeats instantiation.

Method Summary

static java.lang.String	createBeginTag(java.lang.String strBase64TagName) Creates the begin tag for a base 64 encoded string.
static java.lang.String	createEndTag(java.lang.String strBase64TagName) Creates the end tag for a base 64 encoded string.
static byte[]	decode(byte[] source, int off, int len) Decodes Base64 content in byte array format and returns the decoded byte array.
static byte[]	decode(java.lang.String s) Decodes data from Base64 notation.
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.
static java.lang.String	decodeToString(java.lang.String s) Decodes data from Base64 notation and returns it as a string.
static java.lang.String	encode(byte[] source, boolean breakLines) Encodes a byte array into Base64 notation.
static java.lang.String	encode(byte[] source, int off, int len) Encodes a byte array into Base64 notation.
static java.lang.String	encode(byte[] source, int off, int len, boolean breakLines) Encodes a byte array into Base64 notation.
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 java.lang.String	encodeBytes(byte[] source) Encodes a byte array into Base64 notation.
static java.lang.String	encodeString(java.lang.String s) Encodes a string in Base64 notation with line breaks after every 75 Base64 characters.
static java.lang.String	encodeString(java.lang.String s, boolean breakLines) Encodes a string in Base64 notation with line breaks after every 75 Base64 characters.

Methods inherited from class java.lang.Object

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

Field Detail

BEGIN_TAG

public static final java.lang.String BEGIN_TAG

See Also:

Constant Field Values

END_TAG

public static final java.lang.String END_TAG

See Also:

Constant Field Values

TAG_END_SEQUENCE

public static final java.lang.String TAG_END_SEQUENCE

See Also:

Constant Field Values

ENCODE

public static final boolean ENCODE

Specify encoding (value is true).

See Also:

Constant Field Values

DECODE

public static final boolean DECODE

Specify decoding (value is false).

See Also:

Constant Field Values

COMPRESS

public static final boolean COMPRESS

Specify that data should be compressed (value is true).

See Also:

Constant Field Values

DONT_COMPRESS

public static final boolean DONT_COMPRESS

Specify that data should not be compressed (value is false).

See Also:

Constant Field Values

MAX_LINE_LENGTH

private static final int MAX_LINE_LENGTH

Maximum line length (76) of Base64 output.

See Also:

Constant Field Values

EQUALS_SIGN

private static final byte EQUALS_SIGN

The equals sign (=) as a byte.

See Also:

Constant Field Values

NEW_LINE

private static final byte NEW_LINE

The new line character (\n) as a byte.

See Also:

Constant Field Values

ALPHABET

private static final byte[] ALPHABET

The 64 valid Base64 values.

DECODABET

private static final byte[] DECODABET

Translates 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:

Constant Field Values

EQUALS_SIGN_ENC

private static final byte EQUALS_SIGN_ENC

See Also:

Constant Field Values

Constructor Detail

Base64

private Base64()

Defeats instantiation.

Method Detail

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 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.

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

createBeginTag

public static java.lang.String createBeginTag(java.lang.String strBase64TagName)

Creates the begin tag for a base 64 encoded string.

Parameters:

strBase64TagName - the base 64 tag name

Returns:

the begin tag for a base 64 encoded string

createEndTag

public static java.lang.String createEndTag(java.lang.String strBase64TagName)

Creates the end tag for a base 64 encoded string.

Parameters:

strBase64TagName - the base 64 tag name

Returns:

the end tag for a base 64 encoded string

encodeBytes

public static java.lang.String encodeBytes(byte[] source)

Encodes a byte array into Base64 notation. Equivalen to calling encodeBytes( source, 0, source.length )

Parameters:

source - The data to convert

Since:

1.4

encode

public static java.lang.String encode(byte[] source,
                                      boolean breakLines)

Encodes a byte array into Base64 notation. Equivalen to calling encodeBytes( source, 0, source.length )

Parameters:

source - The data to convert

breakLines - Break lines at 80 characters or less.

Returns:

the encoded bytes or null

Since:

1.4

encode

public static java.lang.String encode(byte[] source,
                                      int off,
                                      int len)

Encodes a byte array into Base64 notation.

Parameters:

source - The data to convert

off - Offset in array where conversion should begin

len - Length of data to convert

Since:

1.4

encode

public static java.lang.String encode(byte[] source,
                                      int off,
                                      int len,
                                      boolean breakLines)

Encodes a byte array into Base64 notation.

Parameters:

source - The data to convert

off - Offset in array where conversion should begin

len - Length of data to convert

breakLines - Break lines at 80 characters or less.

Since:

1.4

encodeString

public static java.lang.String encodeString(java.lang.String s)

Encodes a string in Base64 notation with line breaks after every 75 Base64 characters. Of course you probably only need to encode a string if there are non-ASCII characters in it such as many non-English languages.

Parameters:

s - the string to encode

Returns:

the encoded string

Since:

1.3

encodeString

public static java.lang.String encodeString(java.lang.String s,
                                            boolean breakLines)

Encodes a string in Base64 notation with line breaks after every 75 Base64 characters. Of course you probably only need to encode a string if there are non-ASCII characters in it such as many non-English languages.

Parameters:

s - the string to encode

breakLines - Break lines at 80 characters or less.

Returns:

the encoded string or null

Since:

1.3

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 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.

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

Returns:

the number of decoded bytes converted

Since:

1.3

decode

public static byte[] decode(java.lang.String s)

Decodes data from Base64 notation.

Parameters:

s - the string to decode

Returns:

the decoded data

Since:

1.4

decodeToString

public static java.lang.String decodeToString(java.lang.String s)

Decodes data from Base64 notation and returns it as a string. Equivlaent to calling new String( decode( s ) )

Parameters:

s - the strind to decode

Returns:

The data as a string

Since:

1.4

decode

public static byte[] decode(byte[] source,
                            int off,
                            int len)

Decodes Base64 content in byte array format and returns the decoded byte array.

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