org.apache.iotdb.tsfile.encoding.decoder

Class RleDecoder

java.lang.Object

org.apache.iotdb.tsfile.encoding.decoder.Decoder

org.apache.iotdb.tsfile.encoding.decoder.RleDecoder

Direct Known Subclasses:

IntRleDecoder, LongRleDecoder

public abstract class RleDecoder
extends Decoder

Abstract class for all rle decoder. Decoding values according to following grammar: <length> <bitwidth> <encoded-data>. For more information about rle format, see RleEncoder

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	RleDecoder.Mode

Field Summary

Fields

Modifier and Type	Field and Description
protected int	bitPackingNum number of bit-packing group in which is saved in header.
protected int	bitWidth bit width for bit-packing and rle to decode.
protected ByteBuffer	byteCache buffer to save data format like [<bitwidth> <encoded-data>] for decoder.
protected TSFileConfig	config
protected int	currentCount number of data left for reading in current buffer.
protected boolean	isLengthAndBitWidthReaded a flag to indicate whether current pattern is end.
protected int	length how many bytes for all encoded data like [<bitwidth> <encoded-data>] in inputstream.
protected RleDecoder.Mode	mode mode to indicate current encoding type 0 - RLE 1 - BIT_PACKED.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RleDecoder() a constructor, init with endianType, default encoding is TSEncoding.RLE.

Method Summary

Modifier and Type	Method and Description
protected void	callReadBitPackingBuffer(int header)
int	getHeader() get header for both rle and bit-packing current encode mode which is saved in first bit of header.
boolean	hasNext(ByteBuffer buffer) Check whether there is number left for reading.
protected boolean	hasNextPackage() Check whether there is another pattern left for reading.
protected abstract void	initPacker()
BigDecimal	readBigDecimal(ByteBuffer buffer)
Binary	readBinary(ByteBuffer buffer)
protected abstract void	readBitPackingBuffer(int bitPackedGroupCount, int lastBitPackedNum) Read bit-packing package and save them in buffer.
boolean	readBoolean(ByteBuffer buffer)
double	readDouble(ByteBuffer buffer)
float	readFloat(ByteBuffer buffer)
int	readInt(ByteBuffer buffer)
protected void	readLengthAndBitWidth(ByteBuffer buffer) read length and bit width of current package before we decode number.
long	readLong(ByteBuffer buffer)
protected void	readNext() get all encoded data according to mode.
protected abstract void	readNumberInRle() Read rle package and save them in buffer.
short	readShort(ByteBuffer buffer)
void	reset()

Methods inherited from class org.apache.iotdb.tsfile.encoding.decoder.Decoder

getDecoderByType, getType, setType

Methods inherited from class java.lang.Object

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

Field Detail

config

protected TSFileConfig config

mode

protected RleDecoder.Mode mode

mode to indicate current encoding type 0 - RLE 1 - BIT_PACKED.

bitWidth

protected int bitWidth

bit width for bit-packing and rle to decode.

currentCount

protected int currentCount

number of data left for reading in current buffer.

length

protected int length

how many bytes for all encoded data like [<bitwidth> <encoded-data>] in inputstream.

isLengthAndBitWidthReaded

protected boolean isLengthAndBitWidthReaded

a flag to indicate whether current pattern is end. false - need to start reading a new page true - current page isn't over.

byteCache

protected ByteBuffer byteCache

buffer to save data format like [<bitwidth> <encoded-data>] for decoder.

bitPackingNum

protected int bitPackingNum

number of bit-packing group in which is saved in header.

Constructor Detail

RleDecoder

protected RleDecoder()

a constructor, init with endianType, default encoding is TSEncoding.RLE.

Method Detail

reset

public void reset()

Specified by:

reset in class Decoder

getHeader

public int getHeader()
              throws IOException

get header for both rle and bit-packing current encode mode which is saved in first bit of header.

Returns:

int value

Throws:

IOException - cannot get header

readNext

protected void readNext()
                 throws IOException

get all encoded data according to mode.

Throws:

IOException - cannot read next value

callReadBitPackingBuffer

protected void callReadBitPackingBuffer(int header)
                                 throws IOException

Throws:

IOException

readLengthAndBitWidth

protected void readLengthAndBitWidth(ByteBuffer buffer)

read length and bit width of current package before we decode number.

Parameters:

buffer - ByteBuffer

hasNext

public boolean hasNext(ByteBuffer buffer)
                throws IOException

Check whether there is number left for reading.

Specified by:

hasNext in class Decoder

Parameters:

buffer - decoded data saved in ByteBuffer

Returns:

true or false to indicate whether there is number left

Throws:

IOException - cannot check next value

hasNextPackage

protected boolean hasNextPackage()

Check whether there is another pattern left for reading.

Returns:

true or false to indicate whether there is another pattern left

initPacker

protected abstract void initPacker()

readNumberInRle

protected abstract void readNumberInRle()
                                 throws IOException

Read rle package and save them in buffer.

Throws:

IOException - cannot read number

readBitPackingBuffer

protected abstract void readBitPackingBuffer(int bitPackedGroupCount,
                                             int lastBitPackedNum)
                                      throws IOException

Read bit-packing package and save them in buffer.

Parameters:

bitPackedGroupCount - number of group number

lastBitPackedNum - number of useful value in last group

Throws:

IOException - cannot read bit pack

readBoolean

public boolean readBoolean(ByteBuffer buffer)

Overrides:

readBoolean in class Decoder

readShort

public short readShort(ByteBuffer buffer)

Overrides:

readShort in class Decoder

readInt

public int readInt(ByteBuffer buffer)

Overrides:

readInt in class Decoder

readLong

public long readLong(ByteBuffer buffer)

Overrides:

readLong in class Decoder

readFloat

public float readFloat(ByteBuffer buffer)

Overrides:

readFloat in class Decoder

readDouble

public double readDouble(ByteBuffer buffer)

Overrides:

readDouble in class Decoder

readBinary

public Binary readBinary(ByteBuffer buffer)

Overrides:

readBinary in class Decoder

readBigDecimal

public BigDecimal readBigDecimal(ByteBuffer buffer)

Overrides:

readBigDecimal in class Decoder