java.util.zip
Class Adler32

java.lang.Object
  java.util.zip.Adler32

All Implemented Interfaces:

Checksum

public class Adler32

extends Object

implements Checksum

A class that can be used to compute the Adler-32 checksum of a data stream. An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed much faster.

Author:

David Connelly

See Also:

Checksum

Field Summary

private int

adler

Constructor Summary

Adler32()
Creates a new Adler32 object.

Method Summary

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

adler

private int adler

Constructor Detail

Adler32

public Adler32()

Creates a new Adler32 object.

Method Detail

update

public void update(int b)

Updates checksum with specified byte.

Specified by:

update in interface Checksum

Parameters:

b - an array of bytes

update

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

Updates checksum 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.

reset

public void reset()

Resets checksum to initial value.

Specified by:

reset in interface Checksum

getValue

public long getValue()

Returns checksum value.

Specified by:

getValue in interface Checksum

Returns:

the current checksum value

update

private static int update(int adler,
                          int b)

updateBytes

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