org.apache.sysds.runtime.compress.colgroup.offset

Class AOffset

java.lang.Object

org.apache.sysds.runtime.compress.colgroup.offset.AOffset

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

OffsetByte, OffsetChar

public abstract class AOffset
extends Object
implements Serializable

Offset list encoder interface. It is assumed that the input is in sorted order, all values are positive and there are no duplicates. The no duplicate is important since 0 values are exploited to encode an offset of max representable value + 1. This gives the ability to encode data, where the offsets are greater than the available highest value that can be represented size.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
AOffset()

Method Summary

Modifier and Type	Method and Description
void	cacheIterator(AIterator it, int row) Cache a iterator in use, note that there is no check for if the iterator is correctly positioned at the given row
abstract long	getExactSizeOnDisk() Remember to include the ordinal of the type of offset list.
abstract long	getInMemorySize() Get the in memory size of the Offset object
abstract AIterator	getIterator() Get an iterator of the offsets.
AIterator	getIterator(int row) Get an iterator that is pointing at a specific offset.
abstract int	getSize() Get the number of contained elements, This method iterate the entire offset list, so it is not constant lookup.
String	toString()
abstract void	write(DataOutput out) Write the offsets to disk.

Methods inherited from class java.lang.Object

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

Constructor Detail

AOffset

public AOffset()

Method Detail

getIterator

public abstract AIterator getIterator()

Get an iterator of the offsets.

Returns:

AIterator that iterate through index and dictionary offset values.

getIterator

public AIterator getIterator(int row)

Get an iterator that is pointing at a specific offset.

Parameters:

row - The row requested.

Returns:

AIterator that iterate through index and dictionary offset values.

cacheIterator

public void cacheIterator(AIterator it,
                          int row)

Cache a iterator in use, note that there is no check for if the iterator is correctly positioned at the given row

Parameters:

it - The Iterator to cache

row - The row index to cache the iterator as.

write

public abstract void write(DataOutput out)
                    throws IOException

Write the offsets to disk. If you implement another remember to write the ordinal of the new type to disk as well and add it to the OffsetFactory.

Parameters:

out - The output to write to

Throws:

IOException - Exception that happens if the IO fails to write.

getInMemorySize

public abstract long getInMemorySize()

Get the in memory size of the Offset object

Returns:

In memory size as a long.

getExactSizeOnDisk

public abstract long getExactSizeOnDisk()

Remember to include the ordinal of the type of offset list.

Returns:

the size on disk as a long.

getSize

public abstract int getSize()

Get the number of contained elements, This method iterate the entire offset list, so it is not constant lookup.

Returns:

The number of indexes.

toString

public String toString()

Overrides:

toString in class Object