org.ranksys.compression.codecs.dsi

Class BitStreamCODEC

java.lang.Object

org.ranksys.compression.codecs.AbstractCODEC<byte[]>

org.ranksys.compression.codecs.dsi.BitStreamCODEC

All Implemented Interfaces:

Serializable, CODEC<byte[]>

Direct Known Subclasses:

EliasFanoBitStreamCODEC, FixedLengthBitStreamCODEC, GammaBitStreamCODEC, RiceBitStreamCODEC, ZetaBitStreamCODEC

public abstract class BitStreamCODEC
extends AbstractCODEC<byte[]>

Wrapper of dsiutils' BitStreams. Check http://dsiutils.di.unimi.it/

Author:

Saúl Vargas (Saul.Vargas@glasgow.ac.uk)

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
BitStreamCODEC()

Method Summary

Modifier and Type	Method and Description
byte[]	co(int[] in, int offset, int len) Compress.
int	dec(byte[] in, int[] out, int outOffset, int len) Decompress.
boolean	isIntegrated() Returns if the CODEC is integrated, i.e.
protected abstract void	read(it.unimi.dsi.io.InputBitStream ibs, int[] out, int offset, int len) Reads a BitStream to an array.
protected abstract void	write(it.unimi.dsi.io.OutputBitStream obs, int[] in, int offset, int len) Write integer array to BitStream.

Methods inherited from class org.ranksys.compression.codecs.AbstractCODEC

add, reset, stats

Methods inherited from class java.lang.Object

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

Constructor Detail

BitStreamCODEC

public BitStreamCODEC()

Method Detail

co

public byte[] co(int[] in,
                 int offset,
                 int len)

Description copied from interface: CODEC

Compress.

Parameters:

in - array to be compressed.

offset - offset of in

len - number of integers to be compressed

Returns:

compressed representation of the array

write

protected abstract void write(it.unimi.dsi.io.OutputBitStream obs,
                              int[] in,
                              int offset,
                              int len)
                       throws IOException

Write integer array to BitStream.

Parameters:

obs - output bit stream

in - input array

offset - offset of array

len - number of bytes to write

Throws:

IOException - when IO error

dec

public int dec(byte[] in,
               int[] out,
               int outOffset,
               int len)

Description copied from interface: CODEC

Decompress.

Parameters:

in - compressed representation of an array.

out - array where to write the compressed.

outOffset - offset of out

len - number of integers that need to be decompressed

Returns:

currently not used

read

protected abstract void read(it.unimi.dsi.io.InputBitStream ibs,
                             int[] out,
                             int offset,
                             int len)
                      throws IOException

Reads a BitStream to an array.

Parameters:

ibs - input bit stream

out - output array

offset - array offset

len - number of integers to read

Throws:

IOException - when IO error

isIntegrated

public boolean isIntegrated()

Description copied from interface: CODEC

Returns if the CODEC is integrated, i.e. requires that the input is a list of sorted integers (no use of d-gaps required).

Returns:

true is the CODEC is integrated, false otherwise