org.progeeks.util
Class BitInputStream

java.lang.Object
  java.io.InputStream
      org.progeeks.util.BitInputStream

All Implemented Interfaces:

java.io.Closeable

public class BitInputStream
extends java.io.InputStream

Input stream that can provide adjustable bit rate support. Useful for reading 8-bit streams as 7-bit, 6-bit as packed 8-bit, etc.. The only limitation is that target data rates cannot exceed 8 bits due to the InputStream contract.

Version:

$Revision$

Author:

Paul Speed

Constructor Summary

BitInputStream(java.io.InputStream source, int srcBitRate, int targetBitRate, boolean interleave)
Creates an input stream that will translate the bit rate of the underlying stream as specified by the bitrate and interleave parameters.

Method Summary

void	close()
int	read()

Methods inherited from class java.io.InputStream

available, mark, markSupported, read, read, reset, skip

Methods inherited from class java.lang.Object

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

Constructor Detail

BitInputStream

public BitInputStream(java.io.InputStream source,
                      int srcBitRate,
                      int targetBitRate,
                      boolean interleave)

Creates an input stream that will translate the bit rate of the underlying stream as specified by the bitrate and interleave parameters. For example, a stream containing 7-bit elements packed into 8-bit elements could be read by setting the srcBitRate to 8 bits and the target bitrate to 7 bits. The srcBitRate determines how to interpret the 8-bits read from the underlying stream. It is denoting how many of those bits are significant to the target operation. For example, reading from a stream that contains a series of 6-bit values stored in 8-bit entries unpacked (ie: two bits wasted per entry) would be a srcBitRate of 6 bits. So for a packing operation the srcBitRate will be smaller than the targetBitRate. For unpacking operations, the targetBitRate will be smaller than the source.

Parameters:

source - The underlying source data stream.

srcBitRate - The bit rate used to read the source data.

targetBitRate - The bit rate used to interpret the data.

interlave - Set to true if the source bit stream should be treated as if it was read low bit to high for purposes of byte interleaving.

Method Detail

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.InputStream

Throws:

java.io.IOException

read

public int read()
         throws java.io.IOException

Specified by:

read in class java.io.InputStream

Throws:

java.io.IOException