org.freehep.util.io
Class BitInputStream

java.lang.Object
  java.io.InputStream
      org.freehep.util.io.DecompressableInputStream
          org.freehep.util.io.BitInputStream

All Implemented Interfaces:

Closeable

Direct Known Subclasses:

ByteOrderInputStream

public class BitInputStream
extends DecompressableInputStream

Class to read bits from a Stream, allowing for byte synchronization. Signed, Unsigned, Booleans and Floats can be read.

Version:

$Id: BitInputStream.java 8584 2006-08-10 23:06:37Z duns $

Author:

Mark Donszelmann, Charles Loomis

Field Summary

protected static int[]	BIT_MASK
protected static int[]	FIELD_MASK
protected static int	MASK_SIZE
protected static int	ONES
protected static int	ZERO

Constructor Summary

BitInputStream(InputStream in)
Create a Bit input stream from viven input

Method Summary

void	byteAlign() A utility to force the next read to be byte-aligned.
protected void	fetchByte() A utility method to fetch the next byte in preparation for constructing a bit field.
boolean	readBitFlag() Read a bit from the input stream and interpret this as a boolean value.
float	readFBits(int n) Read a float value of n-bits from the stream.
long	readSBits(int n) Read a signed value of n-bits from the input stream.
long	readUBits(int n) Read an unsigned value of n-bits from the input stream.

Methods inherited from class org.freehep.util.io.DecompressableInputStream

read, skip, startDecompressing

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, read, read, reset

Methods inherited from class java.lang.Object

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

Field Detail

MASK_SIZE

protected static final int MASK_SIZE

See Also:

Constant Field Values

ZERO

protected static final int ZERO

See Also:

Constant Field Values

ONES

protected static final int ONES

See Also:

Constant Field Values

BIT_MASK

protected static final int[] BIT_MASK

FIELD_MASK

protected static final int[] FIELD_MASK

Constructor Detail

BitInputStream

public BitInputStream(InputStream in)

Create a Bit input stream from viven input

Parameters:

in - stream to read from

Method Detail

fetchByte

protected void fetchByte()
                  throws IOException

A utility method to fetch the next byte in preparation for constructing a bit field. There is no protection for this method; ensure that it is only called when a byte must be fetched.

Throws:

IOException - if read fails

byteAlign

public void byteAlign()

A utility to force the next read to be byte-aligned.

readBitFlag

public boolean readBitFlag()
                    throws IOException

Read a bit from the input stream and interpret this as a boolean value. A 1-bit is true; a 0-bit is false.

Returns:

true if read bit was 1

Throws:

IOException - if read fails

readSBits

public long readSBits(int n)
               throws IOException

Read a signed value of n-bits from the input stream.

Parameters:

n - number of bits to read

Returns:

value made up of read bits

Throws:

IOException - if read fails

readFBits

public float readFBits(int n)
                throws IOException

Read a float value of n-bits from the stream.

Parameters:

n - number of bits to read

Returns:

value made up of read bits

Throws:

IOException - if read fails

readUBits

public long readUBits(int n)
               throws IOException

Read an unsigned value of n-bits from the input stream.

Parameters:

n - number of bits to read

Returns:

value made up of read bits

Throws:

IOException - if read fails