Package com.twelvemonkeys.imageio.plugins.tiff

Class LZWEncoder

java.lang.Object

com.twelvemonkeys.imageio.plugins.tiff.LZWEncoder

All Implemented Interfaces:

Encoder

final class LZWEncoder
extends java.lang.Object
implements Encoder

LZWEncoder

Inspired by LZWTreeEncoder by Wen Yu and the algorithm described by Bob Montgomery which "[...] uses a tree method to search if a new string is already in the table, which is much simpler, faster, and easier to understand than hashing."

Version:

$Id: LZWEncoder.java,v 1.0 02.12.13 14:13 haraldk Exp$

Field Summary

Fields

Modifier and Type	Field	Description
private int	bitPos
private int	bits
private int	bitsPerCode
private short[]	CHILDREN
(package private) static int	CLEAR_CODE	Clear: Re-initialize tables.
(package private) static int	EOI_CODE	End of Information.
private static int	MAX_BITS
private int	maxCode
private static int	MIN_BITS
private int	nextValidCode
private int	parent
private long	remaining
private short[]	SIBLINGS
private short[]	SUFFIXES
private static int	TABLE_SIZE

Constructor Summary

Constructors

Constructor	Description
LZWEncoder(long length)

Method Summary

Modifier and Type	Method	Description
private static int	bitmaskFor(int bits)
void	encode(java.io.OutputStream stream, java.nio.ByteBuffer buffer)	Encodes up to buffer.remaining() bytes into the given input stream, from the given buffer.
(package private) void	encodeBytes(java.io.OutputStream stream, java.nio.ByteBuffer buffer)
private void	increaseCodeSizeOrResetIfNeeded(java.io.OutputStream stream)
private static int	maxValue(int codeLen)
private void	resetTables()
private void	writeCode(java.io.OutputStream stream, int code)

Methods inherited from class java.lang.Object

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

Field Detail

CLEAR_CODE

static final int CLEAR_CODE

Clear: Re-initialize tables.

See Also:

Constant Field Values

EOI_CODE

static final int EOI_CODE

End of Information.

See Also:

Constant Field Values

MIN_BITS

private static final int MIN_BITS

See Also:

Constant Field Values

MAX_BITS

private static final int MAX_BITS

See Also:

Constant Field Values

TABLE_SIZE

private static final int TABLE_SIZE

See Also:

Constant Field Values

CHILDREN

private final short[] CHILDREN

SIBLINGS

private final short[] SIBLINGS

SUFFIXES

private final short[] SUFFIXES

parent

private int parent

bitsPerCode

private int bitsPerCode

nextValidCode

private int nextValidCode

maxCode

private int maxCode

bits

private int bits

bitPos

private int bitPos

remaining

private long remaining

Constructor Detail

LZWEncoder

LZWEncoder(long length)

Method Detail

encode

public void encode(java.io.OutputStream stream,
                   java.nio.ByteBuffer buffer)
            throws java.io.IOException

Description copied from interface: Encoder

Encodes up to buffer.remaining() bytes into the given input stream, from the given buffer.

Specified by:

encode in interface Encoder

Parameters:

stream - the output stream to encode data to

buffer - buffer to read data from

Throws:

java.io.IOException - if an I/O error occurs

encodeBytes

void encodeBytes(java.io.OutputStream stream,
                 java.nio.ByteBuffer buffer)
          throws java.io.IOException

Throws:

java.io.IOException

increaseCodeSizeOrResetIfNeeded

private void increaseCodeSizeOrResetIfNeeded(java.io.OutputStream stream)
                                      throws java.io.IOException

Throws:

java.io.IOException

resetTables

private void resetTables()

writeCode

private void writeCode(java.io.OutputStream stream,
                       int code)
                throws java.io.IOException

Throws:

java.io.IOException

maxValue

private static int maxValue(int codeLen)

bitmaskFor

private static int bitmaskFor(int bits)