org.codehaus.stax2.typed

Class Base64Variant

java.lang.Object

org.codehaus.stax2.typed.Base64Variant

public final class Base64Variant
extends Object

This abstract base class is used to define specific details of which variant of Base64 encoding/decoding is to be used. Although there is somewhat standard basic version (so-called "MIME Base64"), other variants exists, see Base64 Wikipedia entry for details.

Implementation notes:

• The main complication here is trying to limit access to the underlying efficient encoding/decoding tables -- they are needed for fast operation, but it is potentially risky to expose raw arrays since they can not be protected against modification. The approach here is to try to limit access essentially to the main base64 codec classes; but this leads to bit awkward class structure

Since:

3.0.0

Author:

Tatu Saloranta

Field Summary

Fields

Modifier and Type	Field and Description
static int	BASE64_VALUE_INVALID Marker used to denote ascii characters that do not correspond to a 6-bit value (in this variant), and is not used as a padding character.
static int	BASE64_VALUE_PADDING Marker used to denote ascii character (in decoding table) that is the padding character using this variant (if any).

Constructor Summary

Constructors

Constructor and Description
Base64Variant(Base64Variant base, String name, boolean usesPadding, char paddingChar, int maxLineLength) "Copy constructor" that can be used when the base alphabet is identical to one used by another variant, but other details (padding, maximum line length) differ
Base64Variant(Base64Variant base, String name, int maxLineLength) "Copy constructor" that can be used when the base alphabet is identical to one used by another variant except for the maximum line length (and obviously, name).
Base64Variant(String name, String base64Alphabet, boolean usesPadding, char paddingChar, int maxLineLength)

Method Summary

Methods

Modifier and Type	Method and Description
int	decodeBase64Byte(byte b)
int	decodeBase64Char(char c)
byte	encodeBase64BitsAsByte(int value)
char	encodeBase64BitsAsChar(int value)
int	encodeBase64Chunk(int b24, byte[] buffer, int ptr) Method that encodes given right-aligned (LSB) 24-bit value into 4 base64 bytes (ascii), stored in given result buffer.
int	encodeBase64Chunk(int b24, char[] buffer, int ptr) Method that encodes given right-aligned (LSB) 24-bit value into 4 base64 characters, stored in given result buffer.
int	encodeBase64Partial(int bits, int outputBytes, byte[] buffer, int outPtr) Method that outputs partial chunk (which only encodes one or two bytes of data).
int	encodeBase64Partial(int bits, int outputBytes, char[] buffer, int outPtr) Method that outputs partial chunk (which only encodes one or two bytes of data).
int	getMaxLineLength()
String	getName()
byte	getPaddingByte()
char	getPaddingChar()
String	toString()
boolean	usesPadding()
boolean	usesPaddingChar(char c)

Methods inherited from class java.lang.Object

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

Field Detail

BASE64_VALUE_INVALID

public static final int BASE64_VALUE_INVALID

Marker used to denote ascii characters that do not correspond to a 6-bit value (in this variant), and is not used as a padding character.

See Also:

Constant Field Values

BASE64_VALUE_PADDING

public static final int BASE64_VALUE_PADDING

Marker used to denote ascii character (in decoding table) that is the padding character using this variant (if any).

See Also:

Constant Field Values

Constructor Detail

Base64Variant

public Base64Variant(String name,
             String base64Alphabet,
             boolean usesPadding,
             char paddingChar,
             int maxLineLength)

Base64Variant

public Base64Variant(Base64Variant base,
             String name,
             int maxLineLength)

"Copy constructor" that can be used when the base alphabet is identical to one used by another variant except for the maximum line length (and obviously, name).

Base64Variant

public Base64Variant(Base64Variant base,
             String name,
             boolean usesPadding,
             char paddingChar,
             int maxLineLength)

"Copy constructor" that can be used when the base alphabet is identical to one used by another variant, but other details (padding, maximum line length) differ

Method Detail

getName

public String getName()

usesPadding

public boolean usesPadding()

usesPaddingChar

public boolean usesPaddingChar(char c)

getPaddingChar

public char getPaddingChar()

getPaddingByte

public byte getPaddingByte()

getMaxLineLength

public int getMaxLineLength()

decodeBase64Char

public int decodeBase64Char(char c)

Returns:

6-bit decoded value, if valid character;

decodeBase64Byte

public int decodeBase64Byte(byte b)

encodeBase64BitsAsChar

public char encodeBase64BitsAsChar(int value)

encodeBase64Chunk

public int encodeBase64Chunk(int b24,
                    char[] buffer,
                    int ptr)

Method that encodes given right-aligned (LSB) 24-bit value into 4 base64 characters, stored in given result buffer.

encodeBase64Partial

public int encodeBase64Partial(int bits,
                      int outputBytes,
                      char[] buffer,
                      int outPtr)

Method that outputs partial chunk (which only encodes one or two bytes of data). Data given is still aligned same as if it as full data; that is, missing data is at the "right end" (LSB) of int.

Parameters:

outputBytes - Number of encoded bytes included (either 1 or 2)

encodeBase64BitsAsByte

public byte encodeBase64BitsAsByte(int value)

encodeBase64Chunk

public int encodeBase64Chunk(int b24,
                    byte[] buffer,
                    int ptr)

Method that encodes given right-aligned (LSB) 24-bit value into 4 base64 bytes (ascii), stored in given result buffer.

encodeBase64Partial

public int encodeBase64Partial(int bits,
                      int outputBytes,
                      byte[] buffer,
                      int outPtr)

Method that outputs partial chunk (which only encodes one or two bytes of data). Data given is still aligned same as if it as full data; that is, missing data is at the "right end" (LSB) of int.

Parameters:

outputBytes - Number of encoded bytes included (either 1 or 2)

toString

public String toString()

Overrides:

toString in class Object