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.

Author:

David Connelly

See Also:

Checksum

Field Summary

private int

crc

Constructor Summary

CRC32()
Creates a new CRC32 object.

Method Summary

long	getValue() Returns CRC-32 value.
void	reset() Resets CRC-32 to initial value.
void	update(byte[] b) Updates checksum with specified array of bytes.
void	update(byte[] b, int off, int len) Updates CRC-32 with specified array of bytes.
void	update(int b) Updates CRC-32 with specified byte.
private static int	update(int crc, int b)
private static int	updateBytes(int crc, byte[] b, int off, int len)

Methods inherited from class java.lang.Object

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

Field Detail

crc

private int crc

Constructor Detail

CRC32

public CRC32()

Creates a new CRC32 object.

Method Detail

update

public void update(int b)

Updates CRC-32 with specified byte.

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 CRC-32 with 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

update

public void update(byte[] b)

Updates checksum with specified array of bytes.

Parameters:

b - the array of bytes to update the checksum with

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

update

private static int update(int crc,
                          int b)

updateBytes

private static int updateBytes(int crc,
                               byte[] b,
                               int off,
                               int len)