Class CRC32

java.lang.Object

java.util.zip.CRC32

All Implemented Interfaces:

Checksum

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.

Since:

1.1

Constructor Summary

Constructors

Constructor	Description
CRC32()	Creates a new CRC32 object.

Method Summary

Modifier and Type	Method	Description
long	getValue()	Returns CRC-32 value.
void	reset()	Resets CRC-32 to initial value.
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).
void	update(ByteBuffer buffer)	Updates the CRC-32 checksum with the bytes from the specified buffer.

Methods declared in class Object

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

Modifier and Type	Method	Description
protected Object	clone()	Answers a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o)	Compares the argument to the receiver, and answers true if they represent the same object using a class specific comparison.
protected void	finalize()	Deprecated, for removal: This API element is subject to removal in a future version. May cause performance issues, deadlocks and hangs.
final Class<? extends Object>	getClass()	Answers the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode()	Answers an integer hash code for the receiver.
final void	notify()	Causes one thread which is waiting on the receiver to be made ready to run.
final void	notifyAll()	Causes all threads which are waiting on the receiver to be made ready to run.
String	toString()	Answers a string containing a concise, human-readable description of the receiver.
final void	wait()	Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by notify or notifyAll).
final void	wait(long time)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.
final void	wait(long time, int frac)	Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by notify or notifyAll) or the expiration of the timeout.

Methods declared in interface Checksum

update

Modifier and Type	Method	Description
default void	update(byte[] b)	Updates the current checksum with the specified array of bytes.

Constructor Details

CRC32

public CRC32()

Creates a new CRC32 object.

Method Details

update

public void update(int b)

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

Specified by:

update in interface Checksum

Parameters:

b - the byte to update the checksum with

update

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

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

Specified by:

update in interface Checksum

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 negative or greater than the length of the array b.

update

public void update(ByteBuffer buffer)

Updates the CRC-32 checksum with the bytes from the specified buffer. The checksum is updated with the remaining bytes in the buffer, starting at the buffer's position. Upon return, the buffer's position will be updated to its limit; its limit will not have been changed.

Specified by:

update in interface Checksum

Parameters:

buffer - the ByteBuffer to update the checksum with

Since:

1.8

reset

public void reset()

Resets CRC-32 to initial value.

Specified by:

reset in interface Checksum

getValue

public long getValue()

Returns CRC-32 value.

Specified by:

getValue in interface Checksum

Returns:

the current checksum value