Package com.itextpdf.io.codec

Class LZWCompressor

  • public class LZWCompressor
extends java.lang.Object
    Modified from original LZWCompressor to change interface to passing a buffer of data to be compressed.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      (package private) BitFile bf_
      output destination for bit codes
      (package private) int clearCode_
      reserved clear code based on code size
      (package private) int codeSize_
      base underlying code size of data being compressed 8 for TIFF, 1 to 8 for GIF
      (package private) int endOfInfo_
      reserved end of data code based on code size
      (package private) int limit_
      limit at which current number of bits code size has to be increased
      (package private) LZWStringTable lzss_
      general purpose LZW string table
      (package private) int numBits_
      current number bits output for each code
      (package private) short prefix_
      the prefix code which represents the predecessor string to current input point
      (package private) boolean tiffFudge_
      modify the limits of the code values in LZW encoding due to TIFF bug / feature

    • Constructor Summary

      Constructors 
      Constructor Description
      LZWCompressor​(java.io.OutputStream outputStream, int codeSize, boolean TIFF)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void compress​(byte[] buf, int offset, int length)  
      void flush()
      Indicate to compressor that no more data to go so write out any remaining buffered data.

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • codeSize_

        int codeSize_
        base underlying code size of data being compressed 8 for TIFF, 1 to 8 for GIF

      • clearCode_

        int clearCode_
        reserved clear code based on code size

      • endOfInfo_

        int endOfInfo_
        reserved end of data code based on code size

      • numBits_

        int numBits_
        current number bits output for each code

      • limit_

        int limit_
        limit at which current number of bits code size has to be increased

      • prefix_

        short prefix_
        the prefix code which represents the predecessor string to current input point

      • bf_

        BitFile bf_
        output destination for bit codes

      • tiffFudge_

        boolean tiffFudge_
        modify the limits of the code values in LZW encoding due to TIFF bug / feature

    • Constructor Detail

      • LZWCompressor

        public LZWCompressor​(java.io.OutputStream outputStream,
                     int codeSize,
                     boolean TIFF)
              throws java.io.IOException
        Parameters:
        outputStream - destination for compressed data
        codeSize - the initial code size for the LZW compressor
        TIFF - flag indicating that TIFF lzw fudge needs to be applied
        Throws:
        java.io.IOException - if underlying output stream error

    • Method Detail

      • compress

        public void compress​(byte[] buf,
                     int offset,
                     int length)
              throws java.io.IOException
        Parameters:
        buf - The data to be compressed to output stream
        offset - The offset at which the data starts
        length - The length of the data being compressed
        Throws:
        java.io.IOException - if underlying output stream error

      • flush

        public void flush()
           throws java.io.IOException
        Indicate to compressor that no more data to go so write out any remaining buffered data.
        Throws:
        java.io.IOException - if underlying output stream error