CRC32

public class CRC32 extends Object
implements Checksum

A class that can be used to compute the CRC-32 of a data stream.

Passing a null argument to a method in this class will cause a NullPointerException to be thrown.

See Also

• Checksum

Public Constructor Summary

CRC32() Creates a new CRC32 object.

Public Method Summary

long	getValue() Returns CRC-32 value.
void	reset() Resets CRC-32 to initial value.
void	update(byte[] b) Updates the CRC-32 checksum with the specified array of bytes.
void	update(ByteBuffer buffer) Updates the checksum with the bytes from the specified buffer.
void	update(byte[] b, int off, int len) Updates the CRC-32 checksum with the specified array of bytes.
void	update(int b) Updates the CRC-32 checksum with the specified byte (the low eight bits of the argument b).

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.util.zip.Checksum

abstract long	getValue() Returns the current checksum value.
abstract void	reset() Resets the checksum to its initial value.
abstract void	update(byte[] b, int off, int len) Updates the current checksum with the specified array of bytes.
abstract void	update(int b) Updates the current checksum with the specified byte.

Public Constructors

public CRC32 ()

Creates a new CRC32 object.

Public Methods

public long getValue ()

Returns CRC-32 value.

Returns

• the current checksum value

public void reset ()

Resets CRC-32 to initial value.

public void update (byte[] b)

Updates the CRC-32 checksum with the specified array of bytes.

Parameters

b	the array of bytes to update the checksum with

public void update (ByteBuffer buffer)

Updates the checksum with the bytes from the specified buffer. The checksum is updated using buffer.remaining() bytes starting at buffer.position() Upon return, the buffer's position will be updated to its limit; its limit will not have been changed.

Parameters

buffer	the ByteBuffer to update the checksum with

public void update (byte[] b, int off, int len)

Updates the CRC-32 checksum with the specified array of bytes.

Parameters

b	the byte array to update the checksum with
off	the start offset of the data
len	the number of bytes to use for the update

Throws

ArrayIndexOutOfBoundsException	if off is negative, or len is negative, or off+len is greater than the length of the array b

public void update (int b)

Updates the CRC-32 checksum with the specified byte (the low eight bits of the argument b).

Parameters

b	the byte to update the checksum with