Package com.itextpdf.kernel.pdf.filters

Class LZWDecoder

  • public class LZWDecoder
extends java.lang.Object
    A class for performing LZW decoding.

    • Constructor Summary

      Constructors 
      Constructor Description
      LZWDecoder()
      Creates an LZWDecoder instance.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method 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, java.io.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

    • Field Detail

      • stringTable

        byte[][] stringTable

      • data

        byte[] data

      • uncompData

        java.io.OutputStream uncompData

      • tableIndex

        int tableIndex

      • bitsToGet

        int bitsToGet

      • bytePointer

        int bytePointer

      • bitPointer

        int bitPointer

      • nextData

        int nextData

      • nextBits

        int nextBits

      • andTable

        int[] andTable

    • Constructor Detail

      • LZWDecoder

        public LZWDecoder()
        Creates an LZWDecoder instance.

    • Method Detail

      • decode

        public void decode​(byte[] data,
                   java.io.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