it.unimi.dsi.compression
Class CodeWordCoder

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

All Implemented Interfaces:

Coder, PrefixCoder, Serializable

Direct Known Subclasses:

Fast64CodeWordCoder

public class CodeWordCoder
extends Object
implements PrefixCoder, Serializable

A coder based on a set of codewords.

See Also:

Serialized Form

Field Summary

protected BitVector[]

codeWord The array of codewords of this coder.

Constructor Summary

CodeWordCoder(BitVector[] codeWord)
Creates a new codeword-based coder using the given vector of codewords.

Method Summary

BitVector[]	codeWords() Provides access to the codewords.
BooleanIterator	encode(int symbol) Encodes a symbol.
int	encode(int symbol, OutputBitStream obs) Encodes a symbol.
BooleanIterator	flush() Flushes the coder.
int	flush(OutputBitStream unused) Flushes the coder.

Methods inherited from class java.lang.Object

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

Field Detail

codeWord

protected final BitVector[] codeWord

The array of codewords of this coder.

Constructor Detail

CodeWordCoder

public CodeWordCoder(BitVector[] codeWord)

Creates a new codeword-based coder using the given vector of codewords. The coder will be able to encode symbols numbered from 0 to codeWord.length-1, included.

Parameters:

codeWord - a vector of codewords.

Method Detail

encode

public BooleanIterator encode(int symbol)

Description copied from interface: Coder

Encodes a symbol.

Specified by:

encode in interface Coder

Parameters:

symbol - a symbol.

Returns:

a boolean iterator returning the bits coding symbol.

encode

public int encode(int symbol,
                  OutputBitStream obs)
           throws IOException

Description copied from interface: Coder

Encodes a symbol.

Specified by:

encode in interface Coder

Parameters:

symbol - a symbol.

obs - the output bit stream where the encoded symbol will be written.

Returns:

the number of bits written.

Throws:

IOException

flush

public int flush(OutputBitStream unused)

Description copied from interface: Coder

Flushes the coder. Warning: this method will not flush obs.

Specified by:

flush in interface Coder

Parameters:

unused - the output bit stream where the flushing bits will be written.

Returns:

the number of bits written to flush the coder.

flush

public BooleanIterator flush()

Description copied from interface: Coder

Flushes the coder.

Specified by:

flush in interface Coder

Returns:

a boolean iterator returning the bits used to flush this coder.

codeWords

public BitVector[] codeWords()

Description copied from interface: PrefixCoder

Provides access to the codewords. Warning: bit 0 of each bit vector returned by PrefixCoder.codeWords() is the first (leftmost) bit of the corresponding codeword: in other words, codewords are stored in right-to-left fashion.

Specified by:

codeWords in interface PrefixCoder

Returns:

the codewords.