Stax2 API 4.2.2 · org.codehaus.stax2.typed.Base64Variant

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

Field Summary

Modifier and Type	Field and Description
private final int[]	_asciiToBase64 Decoding table used for base 64 decoding.
private final byte[]	_base64ToAsciiB Alternative encoding table used for base 64 decoding when output is done as ascii bytes.
private final char[]	_base64ToAsciiC Encoding table used for base 64 decoding when output is done as characters.
pack-priv final int	_maxLineLength Maximum number of encoded base64 characters to output during encoding before adding a linefeed, if line length is to be limited (`java.lang.Integer#MAX_VALUE` if not limited).
pack-priv final String	_name Symbolic name of variant; used for diagnostics/debugging.
pack-priv final char	_paddingChar Characted used for padding, if any (`PADDING_CHAR_NONE` if not).
pack-priv final boolean	_usesPadding Whether this variant uses padding or not.
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.
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).
pack-priv static final char	PADDING_CHAR_NONE Placeholder used by "no padding" variant, to be used when a character value is needed.

Constructor Summary

Access	Constructor and Description
public	Base64Variant(String name, String base64Alphabet, boolean usesPadding, char paddingChar, int maxLineLength)
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).
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 Summary

Modifier and Type	Method and Description
public int	decodeBase64Byte(byte b)
public int	Returns: 6-bit decoded value, if valid character; decodeBase64Char(char c)
public byte	encodeBase64BitsAsByte(int value)
public char	encodeBase64BitsAsChar(int value)
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.
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.
public int	encodeBase64Partial(int bits, int Number of encoded bytes included (either 1 or 2) outputBytes, char[] buffer, int outPtr) Method that outputs partial chunk (which only encodes one or two bytes of data).
public int	encodeBase64Partial(int bits, int Number of encoded bytes included (either 1 or 2) outputBytes, byte[] buffer, int outPtr) Method that outputs partial chunk (which only encodes one or two bytes of data).
public int	getMaxLineLength()
public String	getName()
public byte	getPaddingByte()
public char	getPaddingChar()
public String	toString() Overrides java.lang.Object.toString. Returns a string representation of the object.
public boolean	usesPadding()
public boolean	usesPaddingChar(char c)

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll wait wait wait

Field Detail

_asciiToBase64	back to summary
private final int[] _asciiToBase64 Decoding table used for base 64 decoding.

_base64ToAsciiB	back to summary
private final byte[] _base64ToAsciiB Alternative encoding table used for base 64 decoding when output is done as ascii bytes.

_base64ToAsciiC	back to summary
private final char[] _base64ToAsciiC Encoding table used for base 64 decoding when output is done as characters.

_maxLineLength	back to summary
pack-priv final int _maxLineLength Maximum number of encoded base64 characters to output during encoding before adding a linefeed, if line length is to be limited (`java.lang.Integer#MAX_VALUE` if not limited). Note for some output modes (when writing attributes) linefeeds may need to be avoided, and this value ignored.

_name	back to summary
pack-priv final String _name Symbolic name of variant; used for diagnostics/debugging.

_paddingChar	back to summary
pack-priv final char _paddingChar Characted used for padding, if any (`PADDING_CHAR_NONE` if not).

_usesPadding	back to summary
pack-priv final boolean _usesPadding Whether this variant uses padding or not.

BASE64_VALUE_INVALID	back to summary
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.

BASE64_VALUE_PADDING	back to summary
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).

PADDING_CHAR_NONE	back to summary
pack-priv static final char PADDING_CHAR_NONE Placeholder used by "no padding" variant, to be used when a character value is needed.

Constructor Detail

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

Base64Variant	back to summary
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	back to summary
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

decodeBase64Byte	back to summary
public int decodeBase64Byte(byte b)

decodeBase64Char	back to summary
public int decodeBase64Char(char c) Returns:int 6-bit decoded value, if valid character;

encodeBase64BitsAsByte	back to summary
public byte encodeBase64BitsAsByte(int value)

encodeBase64BitsAsChar	back to summary
public char encodeBase64BitsAsChar(int value)

encodeBase64Chunk	back to summary
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.

encodeBase64Chunk	back to summary
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	back to summary
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:int Number of encoded bytes included (either 1 or 2)

encodeBase64Partial

back to summary

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:int: Number of encoded bytes included (either 1 or 2)

encodeBase64Partial	back to summary
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:int Number of encoded bytes included (either 1 or 2)

encodeBase64Partial

back to summary

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:int: Number of encoded bytes included (either 1 or 2)

getMaxLineLength	back to summary
public int getMaxLineLength()

getName	back to summary
public String getName()

getPaddingByte	back to summary
public byte getPaddingByte()

getPaddingChar	back to summary
public char getPaddingChar()

toString	back to summary
public String toString() Overrides java.lang.Object.toString. Doc from java.lang.Object.toString. Returns a string representation of the object. Returns:String a string representation of the object. Annotations @Override

toString

back to summary

public String toString()

Overrides java.lang.Object.toString.

Doc from java.lang.Object.toString.

Returns a string representation of the object.

Returns:String

a string representation of the object.

Annotations

@Override

usesPadding	back to summary
public boolean usesPadding()

usesPaddingChar	back to summary
public boolean usesPaddingChar(char c)

public final Class Base64Variant

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail