Class LZWDecoder

java.lang.Object
com.itextpdf.kernel.pdf.filters.LZWDecoder
public class LZWDecoder extends Object
A class for performing LZW decoding.

  • Field Details

    • stringTable

      byte[][] stringTable

    • data

      byte[] data

    • uncompData

      OutputStream uncompData

    • tableIndex

      int tableIndex

    • bitsToGet

      int bitsToGet

    • bytePointer

      int bytePointer

    • bitPointer

      int bitPointer

    • nextData

      int nextData

    • nextBits

      int nextBits

    • andTable

      int[] andTable

  • Constructor Details

    • LZWDecoder

      public LZWDecoder()
      Creates an LZWDecoder instance.

  • Method Details

    • 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