java.util.zip
Class Adler32

java.lang.Object
  extended byjava.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)