jwo.utils.gifutils
Class BitOutputStream

java.lang.Object
  java.io.OutputStream
      java.io.FilterOutputStream
          jwo.utils.gifutils.BitOutputStream

All Implemented Interfaces:

Closeable, Flushable

Direct Known Subclasses:

GIFOutputStream

public class BitOutputStream
extends FilterOutputStream

Allows the writing of 1 to 32 bits at a time, on any bit boundary. Bits are written to bytes, least significant bit first.

Version:

2.3, 26th August, 1998, modified 11th April, 2006.

Author:

Benjamin E. Norman, Minor modificiations, Jo Wood.

Field Summary

protected int	cachedBits Stores any cached bits which need to be written to the underlying stream.
protected int	numCachedBits Stores the number of valid bits in 'cachedBits' and is never more than 7.

Fields inherited from class java.io.FilterOutputStream

out

Constructor Summary

BitOutputStream(OutputStream os)
Creates a bit output stream based on the given underlying output stream.

Method Summary

void	flush() Flushes any cached bits and bytes.
void	write(int byteValue) Writes a byte at the current bit boundary.
void	writeBit(int bit) Writes a single bit (1 or 0) to the underlying output stream.
void	writeBits(int value, int numBits) Writes the given number of bits (1 to 32) from the given value to the underlying output stream.

Methods inherited from class java.io.FilterOutputStream

close, write, write

Methods inherited from class java.lang.Object

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

Field Detail

cachedBits

protected int cachedBits

Stores any cached bits which need to be written to the underlying stream.

numCachedBits

protected int numCachedBits

Stores the number of valid bits in 'cachedBits' and is never more than 7. Only partial bytes are cached.

Constructor Detail

BitOutputStream

public BitOutputStream(OutputStream os)

Creates a bit output stream based on the given underlying output stream.

Parameters:

os - Output stream to use.

Method Detail

write

public void write(int byteValue)
           throws IOException

Writes a byte at the current bit boundary.

Overrides:

write in class FilterOutputStream

Parameters:

byteValue - Value to write to output stream.

Throws:

IOException - if problem writing to output stream.

writeBits

public void writeBits(int value,
                      int numBits)
               throws IOException

Writes the given number of bits (1 to 32) from the given value to the underlying output stream.

Parameters:

value - Value to write to output stream.

numBits - Number of bits to write.

Throws:

IllegalArgumentException - if numBits is not between 1 and 32.

IOException - if problem writing to output stream.

writeBit

public void writeBit(int bit)
              throws IOException

Writes a single bit (1 or 0) to the underlying output stream.

Parameters:

bit - Bit to write.

Throws:

IOException - if problem writing to output stream.

flush

public void flush()
           throws IOException

Flushes any cached bits and bytes.

Specified by:

flush in interface Flushable

Overrides:

flush in class FilterOutputStream

Throws:

IOException - if problem flushing output stream.