compact1, compact2, compact3

java.util.zip

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.

See Also:

Checksum

Constructor Summary

Constructors

Constructor and Description
CRC32() Creates a new CRC32 object.

Method Summary

Modifier and Type	Method and Description
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(byte[] b, int off, int len) 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(int b) Updates the CRC-32 checksum with the specified byte (the low eight bits of the argument b).

Methods inherited from class java.lang.Object

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

Constructor Detail

CRC32

public CRC32()

Creates a new CRC32 object.

Method Detail

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 greater than the length of the array b

update

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

update

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

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