org.terrier.compression
Class BitFileBuffered.BitInBuffered

java.lang.Object
  org.terrier.compression.BitFileBuffered.BitInBuffered

All Implemented Interfaces:

java.io.Closeable, BitIn

Enclosing class:

BitFileBuffered

protected static class BitFileBuffered.BitInBuffered
extends java.lang.Object
implements BitIn

Implements a BitIn around a RandomDataInput

Field Summary

protected int	bitOffset bit offset in this byte, and in the larger file
protected byte[]	inBuffer buffer for the slice of the file being read
protected long	offset ofset in the larger file
protected RandomDataInput	parentFile parent file
protected int	readByteOffset byte offset within the buffer
protected int	size size of the buffer

Fields inherited from interface org.terrier.compression.BitIn

USUAL_EXTENSION

Constructor Summary

protected	BitFileBuffered.BitInBuffered() empty constructor for child classes
	BitFileBuffered.BitInBuffered(RandomDataInput file, long startByteOffset, byte _bitOffset, int _bufLength) Construct a new BitInBuffered on the specified file, starting at the given offset and with the specified buffer length.

Method Summary

void	align() Aligns the stream to the next byte
void	close() Does nothing
byte	getBitOffset() Returns the bit offset in the last byte.
long	getByteOffset() Returns the byte offset of the stream.
protected void	incrByte() Move forward one byte
protected void	incrByte(int i) Move forward i bytes
int	readBinary(int len) Reads a binary integer from the already read buffer.
int	readDelta() Reads a delta encoded integer from the underlying stream
int	readGamma() Reads a gamma encoded integer from the underlying stream
int	readGolomb(int b) Reads a Golomb encoded integer
protected void	readIn() Reads a new byte from the InputStream if we have finished with the current one.
void	readInterpolativeCoding(int[] data, int localoffset, int len, int lo, int hi) Reads a sequence of numbers from the stream interpolative coded.
int	readMinimalBinary(int b) Reads a binary encoded integer, given an upper bound
int	readMinimalBinaryZero(int b) Reads a minimal binary encoded number, when the upper bound can b zero.
int	readSkewedGolomb(int b) Reads a skewed-golomb encoded integer from the underlying stream Consider a bucket-vector v = <0, 2b, 4b, ...
int	readUnary() Reads a unary encoded integer from the underlying stream
void	skipBits(int len) Skip a number of bits in the current input stream
void	skipBytes(long len) Skip a number of bytes while reading the bit file.

Methods inherited from class java.lang.Object

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

Field Detail

parentFile

protected RandomDataInput parentFile

parent file

offset

protected long offset

ofset in the larger file

inBuffer

protected byte[] inBuffer

buffer for the slice of the file being read

size

protected int size

size of the buffer

readByteOffset

protected int readByteOffset

byte offset within the buffer

bitOffset

protected int bitOffset

bit offset in this byte, and in the larger file

Constructor Detail

BitFileBuffered.BitInBuffered

protected BitFileBuffered.BitInBuffered()

empty constructor for child classes

BitFileBuffered.BitInBuffered

public BitFileBuffered.BitInBuffered(RandomDataInput file,
                                     long startByteOffset,
                                     byte _bitOffset,
                                     int _bufLength)

Construct a new BitInBuffered on the specified file, starting at the given offset and with the specified buffer length.

Parameters:

file - File to seek on

startByteOffset - Start byte offset

_bitOffset - Start bit offset

_bufLength - Number of bytes to buffer

Method Detail

incrByte

protected void incrByte()

Move forward one byte

incrByte

protected void incrByte(int i)

Move forward i bytes

readDelta

public int readDelta()
              throws java.io.IOException

Reads a delta encoded integer from the underlying stream

Specified by:

readDelta in interface BitIn

Returns:

the number read

Throws:

java.io.IOException - if an I/O error occurs

readGamma

public int readGamma()

Reads a gamma encoded integer from the underlying stream

Specified by:

readGamma in interface BitIn

Returns:

the number read

readSkewedGolomb

public int readSkewedGolomb(int b)
                     throws java.io.IOException

Reads a skewed-golomb encoded integer from the underlying stream Consider a bucket-vector v = <0, 2b, 4b, ... , 2^i b, ...> The sum of the elements in the vector goes b, 3b, 7b, 2^(i-1)*b

Specified by:

readSkewedGolomb in interface BitIn

Returns:

the number read

Throws:

java.io.IOException - if an I/O error occurs

readInterpolativeCoding

public void readInterpolativeCoding(int[] data,
                                    int localoffset,
                                    int len,
                                    int lo,
                                    int hi)
                             throws java.io.IOException

Reads a sequence of numbers from the stream interpolative coded.

Specified by:

readInterpolativeCoding in interface BitIn

Parameters:

data - the result vector

localoffset - offset where to write in the vector

len - the number of integers to decode.

lo - a lower bound (the same one passed to writeInterpolativeCoding)

hi - an upper bound (the same one passed to writeInterpolativeCoding)

Throws:

java.io.IOException - if an I/O error occurs

readUnary

public int readUnary()

Reads a unary encoded integer from the underlying stream

Specified by:

readUnary in interface BitIn

Returns:

the number read

readGolomb

public int readGolomb(int b)
               throws java.io.IOException

Reads a Golomb encoded integer

Specified by:

readGolomb in interface BitIn

Parameters:

b - the golomb modulus

Returns:

the int read

Throws:

java.io.IOException - if and I/O error occurs

readMinimalBinary

public int readMinimalBinary(int b)
                      throws java.io.IOException

Reads a binary encoded integer, given an upper bound

Specified by:

readMinimalBinary in interface BitIn

Parameters:

b - the upper bound

Returns:

the int read

Throws:

java.io.IOException - if an I/O error occurs

readMinimalBinaryZero

public int readMinimalBinaryZero(int b)
                          throws java.io.IOException

Reads a minimal binary encoded number, when the upper bound can b zero. Used to interpolative code

Specified by:

readMinimalBinaryZero in interface BitIn

Parameters:

b - the upper bound

Returns:

the int read

Throws:

java.io.IOException - if an I/O error occurs

readIn

protected void readIn()

Reads a new byte from the InputStream if we have finished with the current one.

align

public void align()

Aligns the stream to the next byte

Specified by:

align in interface BitIn

readBinary

public int readBinary(int len)

Reads a binary integer from the already read buffer.

Specified by:

readBinary in interface BitIn

Parameters:

len - the number of binary bits to read

Returns:

the decoded integer

skipBits

public void skipBits(int len)

Skip a number of bits in the current input stream

Specified by:

skipBits in interface BitIn

Parameters:

len - The number of bits to skip

skipBytes

public void skipBytes(long len)
               throws java.io.IOException

Skip a number of bytes while reading the bit file. After this opteration, getBitOffset() == 0, so use skipBits to get getBitOffset() to desired value.

Specified by:

skipBytes in interface BitIn

Parameters:

len - The number of bytes to skip

Throws:

java.io.IOException - if an I/O error occurs

getByteOffset

public long getByteOffset()

Returns the byte offset of the stream. It corresponds to the position of the byte in which the next bit will be written. Use only when writting

Specified by:

getByteOffset in interface BitIn

Returns:

the byte offset in the stream.

getBitOffset

public byte getBitOffset()

Returns the bit offset in the last byte. It corresponds to the position in which the next bit will be written. Use only when writting.

Specified by:

getBitOffset in interface BitIn

Returns:

the bit offset in the stream.

close

public void close()

Does nothing

Specified by:

close in interface java.io.Closeable