it.unimi.dsi.compression
Class CanonicalFast64CodeWordDecoder

java.lang.Object
  it.unimi.dsi.compression.CanonicalFast64CodeWordDecoder

All Implemented Interfaces:

Decoder, Serializable

public final class CanonicalFast64CodeWordDecoder
extends Object
implements Decoder, Serializable

A fast table-based decoder for canonical Huffman codes supporting only codes with limited (less than 64 bits) codewords. We use the technique described by Daniel S. Hirschberg and Debra A. Lelewer, “Efficient Decoding of Prefix Codes”, Comm. ACM, 33(4): 449−459, 1990.

See Also:

Serialized Form

Constructor Summary

CanonicalFast64CodeWordDecoder(int[] codeWordLength, int[] symbol)
Creates a new codeword-based decoder using the given vector of codewords lengths and a symbol array.

Method Summary

int	decode(BooleanIterator iterator) Decodes the next symbol from the given boolean iterator.
int	decode(InputBitStream ibs) Decodes the next symbol from the given input bit stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

CanonicalFast64CodeWordDecoder

public CanonicalFast64CodeWordDecoder(int[] codeWordLength,
                                      int[] symbol)

Creates a new codeword-based decoder using the given vector of codewords lengths and a symbol array.

Parameters:

codeWordLength - a vector of nondecreasing codeword lengths suitable for a canonical code.

symbol - a parallel array of symbols corresponding to each codeword length.

Method Detail

decode

public int decode(BooleanIterator iterator)

Description copied from interface: Decoder

Decodes the next symbol from the given boolean iterator.

Note that InputBitStream implements BooleanIterator.

Specified by:

decode in interface Decoder

Parameters:

iterator - a boolean iterator.

Returns:

the next symbol decoded from the bits emitted by i

decode

public int decode(InputBitStream ibs)
           throws IOException

Description copied from interface: Decoder

Decodes the next symbol from the given input bit stream.

Note that InputBitStream implements BooleanIterator.

Specified by:

decode in interface Decoder

Parameters:

ibs - an input bit stream.

Returns:

the next symbol decoded from ibs.

Throws:

IOException