Package com.webcodepro.shrinkit.io

Class LzwInputStream

java.lang.Object

java.io.InputStream

com.webcodepro.shrinkit.io.LzwInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class LzwInputStream
extends InputStream

This is the generic Shrinkit LZW decompression algorithm. It does not deal with the vagaries of the LZW/1 and LZW/2 data streams. It does, however, deal with dictionary clears (0x100) and the BitInputStream bit sizes.

Constructor Summary

Constructors

Constructor	Description
LzwInputStream(BitInputStream is)	Create the LzwInputStream based on the given BitInputStream.

Method Summary

Modifier and Type	Method	Description
void	clearData()	Provide necessary housekeeping to reset LZW stream between NuFX buffer changes.
void	clearDictionary()	Clear out the dictionary.
void	fillBuffer()	Fill the buffer up with some decompressed data.
int	read()	Answer with the next byte from the (now) decompressed input stream.

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, nullInputStream, read, read, readAllBytes, readNBytes, readNBytes, reset, skip, skipNBytes, transferTo

Methods inherited from class java.lang.Object

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

Constructor Details

LzwInputStream

public LzwInputStream(BitInputStream is)

Create the LzwInputStream based on the given BitInputStream.

See Also:

• BitInputStream

Method Details

read

public int read()
         throws IOException

Answer with the next byte from the (now) decompressed input stream.

Specified by:

read in class InputStream

Throws:

IOException

fillBuffer

public void fillBuffer()
                throws IOException

Fill the buffer up with some decompressed data. This may range from one byte to many bytes, depending on what is in the dictionary.

Throws:

IOException

See Also:

• Wikipedia for the general algorithm

clearDictionary

public void clearDictionary()

Clear out the dictionary. It will be rebuilt on the next call to fillBuffer.

clearData

public void clearData()

Provide necessary housekeeping to reset LZW stream between NuFX buffer changes. The dictionary is the only item that is not cleared -- that needs to be done explicitly since behavior between LZW/1 and LZW/2 differ.