org.apache.iotdb.tsfile.encoding.encoder

Class RegularDataEncoder

java.lang.Object

org.apache.iotdb.tsfile.encoding.encoder.Encoder

org.apache.iotdb.tsfile.encoding.encoder.RegularDataEncoder

Direct Known Subclasses:

RegularDataEncoder.IntRegularEncoder, RegularDataEncoder.LongRegularEncoder

public abstract class RegularDataEncoder
extends Encoder

RegularDataEncoder is an encoder for compressing data in type of integer and long. We adapt a hypothesis that the difference between each data point is the same, which it means the data is regular.

To encode the regular data, we first create an array as a block to store the data loaded into the encoder. While it reach the default block size, start calculating the delta between each data point in this block in order to checkout whether there are missing points exist in the data. If there is, create a bitmap for this block to denote the position of missing points. Next, store the data info (the data size, the minimum delta value and the first data point of this block) and the bitmap with its info into the result byte array output stream.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RegularDataEncoder.IntRegularEncoder
static class	RegularDataEncoder.LongRegularEncoder

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	BLOCK_DEFAULT_SIZE
protected int	blockSize
protected int	dataTotal
protected boolean	isMissingPoint
protected ByteArrayOutputStream	out
protected int	writeIndex

Fields inherited from class org.apache.iotdb.tsfile.encoding.encoder.Encoder

MAX_POINT_NUMBER, MAX_STRING_LENGTH

Constructor Summary

Constructors

Constructor and Description
RegularDataEncoder(int size) constructor of RegularDataEncoder.

Method Summary

Modifier and Type	Method and Description
protected abstract void	checkMissingPoint(ByteArrayOutputStream out)
void	flush(ByteArrayOutputStream out) calling this method to flush all values which haven't encoded to result byte array.
protected void	flushBlockBuffer(ByteArrayOutputStream out)
protected abstract void	reset()
protected abstract void	writeBitmap(ByteArrayOutputStream out)
protected abstract void	writeHeader()
protected void	writeHeaderToBytes()

Methods inherited from class org.apache.iotdb.tsfile.encoding.encoder.Encoder

encode, encode, encode, encode, encode, encode, encode, encode, getMaxByteSize, getOneItemMaxSize, getType, setType

Methods inherited from class java.lang.Object

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

Field Detail

BLOCK_DEFAULT_SIZE

protected static final int BLOCK_DEFAULT_SIZE

See Also:

Constant Field Values

out

protected ByteArrayOutputStream out

blockSize

protected int blockSize

isMissingPoint

protected boolean isMissingPoint

writeIndex

protected int writeIndex

dataTotal

protected int dataTotal

Constructor Detail

RegularDataEncoder

public RegularDataEncoder(int size)

constructor of RegularDataEncoder.

Parameters:

size - - the number how many numbers to be packed into a block.

Method Detail

writeHeader

protected abstract void writeHeader()
                             throws IOException

Throws:

IOException

reset

protected abstract void reset()

checkMissingPoint

protected abstract void checkMissingPoint(ByteArrayOutputStream out)
                                   throws IOException

Throws:

IOException

writeBitmap

protected abstract void writeBitmap(ByteArrayOutputStream out)
                             throws IOException

Throws:

IOException

writeHeaderToBytes

protected void writeHeaderToBytes()
                           throws IOException

Throws:

IOException

flushBlockBuffer

protected void flushBlockBuffer(ByteArrayOutputStream out)
                         throws IOException

Throws:

IOException

flush

public void flush(ByteArrayOutputStream out)

calling this method to flush all values which haven't encoded to result byte array.

Specified by:

flush in class Encoder

Parameters:

out - - ByteArrayOutputStream