eu.unicore.uftp.rsync

Class RollingChecksum

java.lang.Object

eu.unicore.uftp.rsync.RollingChecksum

public class RollingChecksum
extends Object

Compute the rolling checksum.
Based on Andrew Tridgell's 'rsync' as described in http://cs.anu.edu.au/techreports/1996/TR-CS-96-05.pdf

Author:

schuller

Constructor Summary

Constructors

Constructor and Description
RollingChecksum()

Method Summary

Modifier and Type	Method and Description
long	init(byte[] data) initialise the checksum
long	reset(byte[] data, long k, long l) reset the checksum using the given block data
long	update(long k, long l, byte X_k, byte X_l) compute the rolling checksum for the given parameters

Methods inherited from class java.lang.Object

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

Constructor Detail

RollingChecksum

public RollingChecksum()

Method Detail

init

public long init(byte[] data)

initialise the checksum

Parameters:

data - - initial data block

Returns:

reset

public long reset(byte[] data,
                  long k,
                  long l)

reset the checksum using the given block data

Parameters:

data - - data block

k - - start position

l - - end position

Returns:

the checksum of the given block

update

public long update(long k,
                   long l,
                   byte X_k,
                   byte X_l)

compute the rolling checksum for the given parameters

Parameters:

k - - start index

l - - end index

X_k - - the data value at position 'k'

X_l - - the data value at position 'l'

Returns:

checksum value for the block from 'k' to 'l'