com.webcodepro.shrinkit.io

Class BitOutputStream

java.lang.Object

java.io.OutputStream

com.webcodepro.shrinkit.io.BitOutputStream

All Implemented Interfaces:

BitConstants, java.io.Closeable, java.io.Flushable, java.lang.AutoCloseable

public class BitOutputStream
extends java.io.OutputStream
implements BitConstants

The BitOutputStream allows varying bit sizes to be written to the wrapped OutputStream. This is useful for LZW type compression algorithms where 9-12 bit codes are used instead of the 8-bit byte.

Warning: The write(byte[]) and write(byte[], int, int) methods of OutputStream will not work appropriately with any bit size > 8 bits.

Field Summary

Fields inherited from interface com.webcodepro.shrinkit.io.BitConstants

BIT_MASKS

Constructor Summary

Constructors

Constructor and Description
BitOutputStream(java.io.OutputStream os, int startingNumberOfBits) Create a BitOutpuStream wrapping the given OutputStream and writing the number of bits specified.

Method Summary

Modifier and Type	Method and Description
void	clearRemainingBitsOfData() When shifting from buffer to buffer, this OutputStream also should be reset.
void	close() Close the output stream and write any remaining byte to the output.
int	getBitMask() Answer with the current bit mask for the current bit size.
void	increaseRequestedNumberOfBits() Increase the requested number of bits by one.
void	setRequestedNumberOfBits(int numberOfBits) Set the number of bits to be write with each call to write(int).
void	write(int b) Write the number of bits to the wrapped OutputStream.

Methods inherited from class java.io.OutputStream

flush, write, write

Methods inherited from class java.lang.Object

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

Constructor Detail

BitOutputStream

public BitOutputStream(java.io.OutputStream os,
                       int startingNumberOfBits)

Create a BitOutpuStream wrapping the given OutputStream and writing the number of bits specified.

Method Detail

setRequestedNumberOfBits

public void setRequestedNumberOfBits(int numberOfBits)

Set the number of bits to be write with each call to write(int).

increaseRequestedNumberOfBits

public void increaseRequestedNumberOfBits()

Increase the requested number of bits by one. This is the general usage and prevents client from needing to track the requested number of bits or from making various method calls.

getBitMask

public int getBitMask()

Answer with the current bit mask for the current bit size.

write

public void write(int b)
           throws java.io.IOException

Write the number of bits to the wrapped OutputStream.

Specified by:

write in class java.io.OutputStream

Throws:

java.io.IOException

clearRemainingBitsOfData

public void clearRemainingBitsOfData()

When shifting from buffer to buffer, this OutputStream also should be reset. This allows the "left over" bits to be cleared.

close

public void close()
           throws java.io.IOException

Close the output stream and write any remaining byte to the output. Note that we may very well end up with extra bits if there are < 8 bits remaining.

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException