org.cryptacular.codec

Class AbstractBaseNEncoder

java.lang.Object

org.cryptacular.codec.AbstractBaseNEncoder

All Implemented Interfaces:

Encoder

Direct Known Subclasses:

Base32Encoder, Base64Encoder

public abstract class AbstractBaseNEncoder
extends java.lang.Object
implements Encoder

Base encoder class for encoding schemes described in RFC 3548.

Field Summary

Fields

Modifier and Type	Field and Description
private int	bitsPerChar Number of bits encoding a single character.
private long	block Holds a block of bytes to encode.
private int	blockLength Number of bits in a block.
private char[]	charset Encoding character set.
private long	initialBitMask Initial bit mask for selecting characters in a block.
protected int	lineLength Number of base64 characters per line.
private static java.lang.String	NEWLINE Platform-specific line terminator string, e.g.
private int	outCount Number of characters written.
private int	remaining Number of bits in encode block remaining.

Constructor Summary

Constructors

Constructor and Description
AbstractBaseNEncoder(char[] characterSet, int charactersPerLine) Creates a new instance with given parameters.

Method Summary

Modifier and Type	Method and Description
void	encode(java.nio.ByteBuffer input, java.nio.CharBuffer output) Encodes bytes in input buffer into characters placed in the output buffer.
void	finalize(java.nio.CharBuffer output) Performs final output encoding (e.g.
protected abstract int	getBitsPerChar()
protected abstract int	getBlockLength()
int	outputSize(int inputSize) Expected number of characters in the output buffer for an input buffer of the given size.
private void	writeOutput(java.nio.CharBuffer output, int stop) Writes bytes in the current encoding block to the output buffer.

Methods inherited from class java.lang.Object

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

Field Detail

NEWLINE

private static final java.lang.String NEWLINE

Platform-specific line terminator string, e.g. LF (Unix), CRLF (Windows).

lineLength

protected final int lineLength

Number of base64 characters per line.

charset

private final char[] charset

Encoding character set.

blockLength

private final int blockLength

Number of bits in a block.

bitsPerChar

private final int bitsPerChar

Number of bits encoding a single character.

initialBitMask

private final long initialBitMask

Initial bit mask for selecting characters in a block.

block

private long block

Holds a block of bytes to encode.

remaining

private int remaining

Number of bits in encode block remaining.

outCount

private int outCount

Number of characters written.

Constructor Detail

AbstractBaseNEncoder

public AbstractBaseNEncoder(char[] characterSet,
                            int charactersPerLine)

Creates a new instance with given parameters.

Parameters:

characterSet - Encoding character set.

charactersPerLine - Number of characters per line.

Method Detail

encode

public void encode(java.nio.ByteBuffer input,
                   java.nio.CharBuffer output)
            throws EncodingException

Description copied from interface: Encoder

Encodes bytes in input buffer into characters placed in the output buffer. This method may be called multiple times, followed by Encoder.finalize(java.nio.CharBuffer) after all input bytes have been provided.

Specified by:

encode in interface Encoder

Parameters:

input - Input byte buffer.

output - Output character buffer.

Throws:

EncodingException - on encoding errors.

finalize

public void finalize(java.nio.CharBuffer output)
              throws EncodingException

Description copied from interface: Encoder

Performs final output encoding (e.g. padding) after all input bytes have been provided.

Specified by:

finalize in interface Encoder

Parameters:

output - Output character buffer.

Throws:

EncodingException - on encoding errors.

outputSize

public int outputSize(int inputSize)

Description copied from interface: Encoder

Expected number of characters in the output buffer for an input buffer of the given size.

Specified by:

outputSize in interface Encoder

Parameters:

inputSize - Size of input buffer in bytes.

Returns:

Minimum character buffer size required to store all encoded input bytes.

getBlockLength

protected abstract int getBlockLength()

Returns:

Number of bits in a block of encoded characters.

getBitsPerChar

protected abstract int getBitsPerChar()

Returns:

Number of bits encoding a single character.

writeOutput

private void writeOutput(java.nio.CharBuffer output,
                         int stop)

Writes bytes in the current encoding block to the output buffer.

Parameters:

output - Output buffer.

stop - Bit shift stop position where data in current encoding block ends.