Class SimpleHuffProcessor

java.lang.Object

SimpleHuffProcessor

All Implemented Interfaces:

IHuffConstants, IHuffProcessor

public class SimpleHuffProcessor
extends Object
implements IHuffProcessor

Field Summary

Fields inherited from interface IHuffConstants

ALPH_SIZE, BITS_PER_INT, BITS_PER_WORD, MAGIC_NUMBER, STORE_COUNTS, STORE_CUSTOM, STORE_TREE

Constructor Summary

Constructors

Constructor and Description
SimpleHuffProcessor()

Method Summary

Methods

Modifier and Type	Method and Description
int	compress(InputStream in, OutputStream out, boolean force) Compresses input to output, where the same InputStream has previously been pre-processed via preprocessCompress storing state used by this call.
int	preprocessCompress(InputStream in, int headerFormat) Preprocess data so that compression is possible --- count characters/create tree/store state so that a subsequent call to compress will work.
void	setViewer(IHuffViewer viewer) Make sure this model communicates with some view.
int	uncompress(InputStream in, OutputStream out) Uncompress a previously compressed stream in, writing the uncompressed bits/data to out.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleHuffProcessor

public SimpleHuffProcessor()

Method Detail

compress

public int compress(InputStream in,
           OutputStream out,
           boolean force)
             throws IOException

Description copied from interface: IHuffProcessor

Compresses input to output, where the same InputStream has previously been pre-processed via preprocessCompress storing state used by this call.
pre: preprocessCompress must be called before this method

Specified by:

compress in interface IHuffProcessor

Parameters:

in - is the stream being compressed (NOT a BitInputStream)

out - is bound to a file/stream to which bits are written for the compressed file (not a BitOutputStream)

force - if this is true create the output file even if it is larger than the input file. If this is false do not create the output file if it is larger than the input file.

Returns:

the number of bits written.

Throws:

IOException - if an error occurs while reading from the input file or writing to the output file.

preprocessCompress

public int preprocessCompress(InputStream in,
                     int headerFormat)
                       throws IOException

Description copied from interface: IHuffProcessor

Preprocess data so that compression is possible --- count characters/create tree/store state so that a subsequent call to compress will work. The InputStream is not a BitInputStream, so wrap it int one as needed.

Specified by:

preprocessCompress in interface IHuffProcessor

Parameters:

in - is the stream which could be subsequently compressed

headerFormat - a constant from IHuffProcessor that determines what kind of header to use, standard count format, standard tree format, or possibly some format added in the future.

Returns:

number of bits saved by compression or some other measure Note, to determine the number of bits saved, the number of bits written includes ALL bits that will be written including the magic number, the header format number, the header to reproduce the tree, AND the actual data.

Throws:

IOException - if an error occurs while reading from the input file.

setViewer

public void setViewer(IHuffViewer viewer)

Description copied from interface: IHuffProcessor

Make sure this model communicates with some view.

Specified by:

setViewer in interface IHuffProcessor

Parameters:

viewer - is the view for communicating.

uncompress

public int uncompress(InputStream in,
             OutputStream out)
               throws IOException

Description copied from interface: IHuffProcessor

Uncompress a previously compressed stream in, writing the uncompressed bits/data to out.

Specified by:

uncompress in interface IHuffProcessor

Parameters:

in - is the previously compressed data (not a BitInputStream)

out - is the uncompressed file/stream

Returns:

the number of bits written to the uncompressed file/stream

Throws:

IOException - if an error occurs while reading from the input file or writing to the output file.