fi.helsinki.cs.ohtu.mpeg2.util
Class UnsignedIntegerField

java.lang.Object
  fi.helsinki.cs.ohtu.mpeg2.util.UnsignedIntegerField

public class UnsignedIntegerField
extends java.lang.Object

Represents an unsigned integer field in a MPEG stream. Fields have specific bit widths. This class enforces the width by not allowing setting values which won't fit into a field with the given size as unsigned binary integers. This limit is called the maximum width. In addition to the maximum width of the field, a minimum width for serializing to a bit stream can be specified. Any value in the field at the time of writing will be padded with zero bits, written before the actual value bits to the stream. The maximum width of a field supported by this class is one less than Long.SIZE. The highest bit in a long integer is used for the sign bit, which makes no sense in the unsigned integer context.

Field Summary

private int	maxWidth
private int	minWidth
private long	value
private int	width

Constructor Summary

UnsignedIntegerField(int width)
Constructs a new instance which is effectively fixed width.

UnsignedIntegerField(int minWidth, int maxWidth, long value)
Constructs a new instance with variable width.

UnsignedIntegerField(int width, long value)
Constructs a new instance which is effectively fixed width.

Method Summary

int	getMaxWidth() Gets the maximum width of the field.
int	getMinWidth() Gets the minimum width of the field.
long	getValue() Gets the value of the field.
void	setValue(long newValue) Sets the value of the field.
void	writeTo(BitOutputStream stream) Writes the value of the field to the given stream.

Methods inherited from class java.lang.Object

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

Field Detail

minWidth

private final int minWidth

maxWidth

private final int maxWidth

width

private int width

value

private long value

Constructor Detail

UnsignedIntegerField

public UnsignedIntegerField(int width)

Constructs a new instance which is effectively fixed width.

Parameters:

width - The width of the field, in bits. Both maximum and minimum width are set to this.

UnsignedIntegerField

public UnsignedIntegerField(int width,
                            long value)

Constructs a new instance which is effectively fixed width.

Parameters:

width - The width of the field, in bits.Both maximum and minimum width are set to this.

value - The initial value to set the field to, as if setValue() was called.

UnsignedIntegerField

public UnsignedIntegerField(int minWidth,
                            int maxWidth,
                            long value)

Constructs a new instance with variable width.

Parameters:

minWidth - Minimal allowed width for the field, in bits.

maxWidth - Maximum allowed width for the field, in bits.

value - The initial value to set the field to, as if setValue() was called.

Method Detail

getMaxWidth

public int getMaxWidth()

Gets the maximum width of the field.

Returns:

the maximum width

getMinWidth

public int getMinWidth()

Gets the minimum width of the field.

Returns:

the minimum width

getValue

public long getValue()

Gets the value of the field.

Returns:

The value of the field.

setValue

public void setValue(long newValue)

Sets the value of the field.

Parameters:

newValue - The value to set the field to.

writeTo

public void writeTo(BitOutputStream stream)
             throws java.io.IOException

Writes the value of the field to the given stream.

Parameters:

stream - The bit stream to write to.

Throws:

java.io.IOException