com.itextpdf.kernel.pdf.filters

Class LZWDecoder

java.lang.Object

com.itextpdf.kernel.pdf.filters.LZWDecoder

public class LZWDecoder
extends Object

A class for performing LZW decoding.

Constructor Summary

Constructors

Constructor and Description
LZWDecoder() Creates an LZWDecoder instance.

Method Summary

Modifier and Type	Method and Description
void	addStringToTable(byte[] string) Add a new string to the string table.
void	addStringToTable(byte[] oldString, byte newString) Add a new string to the string table.
byte[]	composeString(byte[] oldString, byte newString) Append newString to the end of oldString.
void	decode(byte[] data, OutputStream uncompData) Method to decode LZW compressed data.
int	getNextCode() Attempt to get the next code.
void	initializeStringTable() Initialize the string table.
void	writeString(byte[] string) Write out the string just uncompressed.

Methods inherited from class java.lang.Object

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

Constructor Detail

LZWDecoder

public LZWDecoder()

Creates an LZWDecoder instance.

Method Detail

decode

public void decode(byte[] data,
                   OutputStream uncompData)

Method to decode LZW compressed data.

Parameters:

data - The compressed data.

uncompData - Array to return the uncompressed data in.

initializeStringTable

public void initializeStringTable()

Initialize the string table.

writeString

public void writeString(byte[] string)

Write out the string just uncompressed.

Parameters:

string - content to write to the uncompressed data

addStringToTable

public void addStringToTable(byte[] oldString,
                             byte newString)

Add a new string to the string table.

Parameters:

oldString - stored string

newString - string to be appended to the stored string

addStringToTable

public void addStringToTable(byte[] string)

Add a new string to the string table.

Parameters:

string - byte[] to store in the string table

composeString

public byte[] composeString(byte[] oldString,
                            byte newString)

Append newString to the end of oldString.

Parameters:

oldString - string be appended to

newString - string that is to be appended to oldString

Returns:

combined string

getNextCode

public int getNextCode()

Attempt to get the next code. Exceptions are caught to make this robust to cases wherein the EndOfInformation code has been omitted from a strip. Examples of such cases have been observed in practice.

Returns:

next code