uk.ac.gla.terrier.compression
Interface BitOut

All Superinterfaces:

java.io.Closeable

All Known Implementing Classes:

BitByteOutputStream, BitFile, BitOutputStream, MemorySBOS, OldBitFile, OldBitOutputStream

public interface BitOut
extends java.io.Closeable

Interface describing the writing compression methods supported by the BitFile classes.

Since:

2.0

Version:

$Revision: 1.4 $

Author:

Craig Macdonald

Method Summary

byte	getBitOffset() Returns the bit offset in the last byte.
long	getByteOffset() Returns the byte offset of the stream.
int	writeBinary(int len, int x) Writes an integer in binary format to the stream.
int	writeGamma(int x) Writes an integer x into the stream using gamma encoding.
int	writeUnary(int x) Writes an integer x using unary encoding.

Methods inherited from interface java.io.Closeable

close

Method Detail

getByteOffset

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.

Returns:

the byte offset in the stream.

getBitOffset

byte getBitOffset()

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

Returns:

the bit offset in the stream.

writeUnary

int writeUnary(int x)
               throws java.io.IOException

Writes an integer x using unary encoding. The encoding is a sequence of x -1 zeros and 1 one: 1, 01, 001, 0001, etc .. This method is not failsafe, it doesn't check if the argument is 0 or negative.

Parameters:

x - the number to write

Returns:

the number of bits written

Throws:

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

writeGamma

int writeGamma(int x)
               throws java.io.IOException

Writes an integer x into the stream using gamma encoding. This method is not failsafe, it doesn't check if the argument is 0 or negative.

Parameters:

x - the int number to write

Returns:

the number of bits written

Throws:

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

writeBinary

int writeBinary(int len,
                int x)
                throws java.io.IOException

Writes an integer in binary format to the stream.

Parameters:

len - size in bits of the number.

x - the integer to write.

Returns:

the number of bits written.

Throws:

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