Package net.sf.jazzlib

Class Inflater

java.lang.Object
net.sf.jazzlib.Inflater
public class Inflater extends Object
Inflater is used to decompress data that has been compressed according to the "deflate" standard described in rfc1950. The usage is as following. First you have to set some input with setInput(), then inflate() it. If inflate doesn't inflate any bytes there may be three reasons:
  • needsInput() returns true because the input buffer is empty. You have to provide more input with setInput(). NOTE: needsInput() also returns true when, the stream is finished.
  • needsDictionary() returns true, you have to provide a preset dictionary with setDictionary().
  • finished() returns true, the inflater has finished.
Once the first output byte is produced, a dictionary will not be needed at a later stage.
Since:
JDK 1.1

  • Field Details

    • CPLENS

      private static final int[] CPLENS

    • CPLEXT

      private static final int[] CPLEXT

    • CPDIST

      private static final int[] CPDIST

    • CPDEXT

      private static final int[] CPDEXT

    • DECODE_HEADER

      private static final int DECODE_HEADER
      See Also:

    • DECODE_DICT

      private static final int DECODE_DICT
      See Also:

    • DECODE_BLOCKS

      private static final int DECODE_BLOCKS
      See Also:

    • DECODE_STORED_LEN1

      private static final int DECODE_STORED_LEN1
      See Also:

    • DECODE_STORED_LEN2

      private static final int DECODE_STORED_LEN2
      See Also:

    • DECODE_STORED

      private static final int DECODE_STORED
      See Also:

    • DECODE_DYN_HEADER

      private static final int DECODE_DYN_HEADER
      See Also:

    • DECODE_HUFFMAN

      private static final int DECODE_HUFFMAN
      See Also:

    • DECODE_HUFFMAN_LENBITS

      private static final int DECODE_HUFFMAN_LENBITS
      See Also:

    • DECODE_HUFFMAN_DIST

      private static final int DECODE_HUFFMAN_DIST
      See Also:

    • DECODE_HUFFMAN_DISTBITS

      private static final int DECODE_HUFFMAN_DISTBITS
      See Also:

    • DECODE_CHKSUM

      private static final int DECODE_CHKSUM
      See Also:

    • FINISHED

      private static final int FINISHED
      See Also:

    • mode

      private int mode
      This variable contains the current state.

    • readAdler

      private int readAdler
      The adler checksum of the dictionary or of the decompressed stream, as it is written in the header resp. footer of the compressed stream.
      Only valid if mode is DECODE_DICT or DECODE_CHKSUM.

    • neededBits

      private int neededBits
      The number of bits needed to complete the current state. This is valid, if mode is DECODE_DICT, DECODE_CHKSUM, DECODE_HUFFMAN_LENBITS or DECODE_HUFFMAN_DISTBITS.

    • repLength

      private int repLength

    • repDist

      private int repDist

    • uncomprLen

      private int uncomprLen

    • isLastBlock

      private boolean isLastBlock
      True, if the last block flag was set in the last block of the inflated stream. This means that the stream ends after the current block.

    • totalOut

      private int totalOut
      The total number of inflated bytes.

    • totalIn

      private int totalIn
      The total number of bytes set with setInput(). This is not the value returned by getTotalIn(), since this also includes the unprocessed input.

    • nowrap

      private final boolean nowrap
      This variable stores the nowrap flag that was given to the constructor. True means, that the inflated stream doesn't contain a header nor the checksum in the footer.

    • input

      private StreamManipulator input

    • outputWindow

      private OutputWindow outputWindow

    • dynHeader

      private InflaterDynHeader dynHeader

    • litlenTree

      private InflaterHuffmanTree litlenTree

    • distTree

      private InflaterHuffmanTree distTree

    • adler

      private Adler32 adler

  • Constructor Details

    • Inflater

      public Inflater()
      Creates a new inflater.

    • Inflater

      public Inflater(boolean nowrap)
      Creates a new inflater.
      Parameters:
      nowrap - true if no header and checksum field appears in the stream. This is used for GZIPed input. For compatibility with Sun JDK you should provide one byte of input more than needed in this case.

  • Method Details

    • finalize

      protected void finalize()
      Finalizes this object.
      Overrides:
      finalize in class Object

    • end

      @Deprecated public void end()
      Deprecated.
      Just clear all references to inflater instead.
      Frees all objects allocated by the inflater. There's no reason to call this, since you can just rely on garbage collection (even for the Sun implementation). Exists only for compatibility with Sun's JDK, where the compressor allocates native memory. If you call any method (even reset) afterwards the behaviour is undefined.

    • finished

      public boolean finished()
      Returns true, if the inflater has finished. This means, that no input is needed and no output can be produced.

    • getAdler

      public int getAdler()
      Gets the adler checksum. This is either the checksum of all uncompressed bytes returned by inflate(), or if needsDictionary() returns true (and thus no output was yet produced) this is the adler checksum of the expected dictionary.

    • getRemaining

      public int getRemaining()
      Gets the number of unprocessed input. Useful, if the end of the stream is reached and you want to further process the bytes after the deflate stream.
      Returns:
      the number of bytes of the input which were not processed.

    • getTotalIn

      public int getTotalIn()
      Gets the total number of processed compressed input bytes.
      Returns:
      the total number of bytes of processed input bytes.

    • getTotalOut

      public int getTotalOut()
      Gets the total number of output bytes returned by inflate().
      Returns:
      the total number of output bytes.

    • inflate

      public int inflate(byte[] buf) throws DataFormatException
      Inflates the compressed stream to the output buffer. If this returns 0, you should check, whether needsDictionary(), needsInput() or finished() returns true, to determine why no further output is produced.
      Parameters:
      buffer - the output buffer.
      Returns:
      the number of bytes written to the buffer, 0 if no further output can be produced.
      Throws:
      DataFormatException - if deflated stream is invalid.
      IllegalArgumentException - if buf has length 0.

    • inflate

      public int inflate(byte[] buf, int off, int len) throws DataFormatException
      Inflates the compressed stream to the output buffer. If this returns 0, you should check, whether needsDictionary(), needsInput() or finished() returns true, to determine why no further output is produced.
      Parameters:
      off - the offset into buffer where the output should start.
      len - the maximum length of the output.
      buffer - the output buffer.
      Returns:
      the number of bytes written to the buffer, 0 if no further output can be produced.
      Throws:
      DataFormatException - if deflated stream is invalid.
      IndexOutOfBoundsException - if the off and/or len are wrong.

    • needsDictionary

      public boolean needsDictionary()
      Returns true, if a preset dictionary is needed to inflate the input.

    • needsInput

      public boolean needsInput()
      Returns true, if the input buffer is empty. You should then call setInput().
      NOTE: This method also returns true when the stream is finished.

    • reset

      public void reset()
      Resets the inflater so that a new stream can be decompressed. All pending input and output will be discarded.

    • setDictionary

      public void setDictionary(byte[] buffer)
      Sets the preset dictionary. This should only be called, if needsDictionary() returns true and it should set the same dictionary, that was used for deflating. The getAdler() function returns the checksum of the dictionary needed.
      Parameters:
      buffer - the dictionary.
      Throws:
      IllegalStateException - if no dictionary is needed.
      IllegalArgumentException - if the dictionary checksum is wrong.

    • setDictionary

      public void setDictionary(byte[] buffer, int off, int len)
      Sets the preset dictionary. This should only be called, if needsDictionary() returns true and it should set the same dictionary, that was used for deflating. The getAdler() function returns the checksum of the dictionary needed.
      Parameters:
      buffer - the dictionary.
      off - the offset into buffer where the dictionary starts.
      len - the length of the dictionary.
      Throws:
      IllegalStateException - if no dictionary is needed.
      IllegalArgumentException - if the dictionary checksum is wrong.
      IndexOutOfBoundsException - if the off and/or len are wrong.

    • setInput

      public void setInput(byte[] buf)
      Sets the input. This should only be called, if needsInput() returns true.
      Parameters:
      buffer - the input.
      Throws:
      IllegalStateException - if no input is needed.

    • setInput

      public void setInput(byte[] buf, int off, int len)
      Sets the input. This should only be called, if needsInput() returns true.
      Parameters:
      off - the offset into buffer where the input starts.
      len - the length of the input.
      buffer - the input.
      Throws:
      IllegalStateException - if no input is needed.
      IndexOutOfBoundsException - if the off and/or len are wrong.

    • decodeHeader

      private boolean decodeHeader() throws DataFormatException
      Decodes the deflate header.
      Returns:
      false if more input is needed.
      Throws:
      DataFormatException - if header is invalid.

    • decodeDict

      private boolean decodeDict()
      Decodes the dictionary checksum after the deflate header.
      Returns:
      false if more input is needed.

    • decodeHuffman

      private boolean decodeHuffman() throws DataFormatException
      Decodes the huffman encoded symbols in the input stream.
      Returns:
      false if more input is needed, true if output window is full or the current block ends.
      Throws:
      DataFormatException - if deflated stream is invalid.

    • decodeChksum

      private boolean decodeChksum() throws DataFormatException
      Decodes the adler checksum after the deflate stream.
      Returns:
      false if more input is needed.
      Throws:
      DataFormatException - if checksum doesn't match.

    • decode

      private boolean decode() throws DataFormatException
      Decodes the deflated stream.
      Returns:
      false if more input is needed, or if finished.
      Throws:
      DataFormatException - if deflated stream is invalid.