io.milton.zsync

Interface RollingChecksum

All Superinterfaces:

Cloneable, Serializable

All Known Implementing Classes:

Rsum

public interface RollingChecksum
extends Cloneable, Serializable

A general interface for 32-bit checksums that have the "rolling" property.

Version:

$Revision: 1.8 $

Author:

Casey Marshall

Method Summary

Modifier and Type	Method and Description
void	check(byte[] buf, int offset, int length) Replaces the current internal state with entirely new data.
Object	clone() Copies this checksum instance into a new instance.
boolean	equals(Object o) Tests if a particular checksum is equal to this checksum.
void	first(byte[] buf, int offset, int length) Replaces the current internal state with entirely new data.
int	getValue() Returns the currently-computed 32-bit checksum.
void	reset() Resets the internal state of the checksum, so it may be re-used later.
void	roll(byte b) Update the checksum with a single byte.

Method Detail

getValue

int getValue()

Returns the currently-computed 32-bit checksum.

Returns:

The checksum.

reset

void reset()

Resets the internal state of the checksum, so it may be re-used later.

roll

void roll(byte b)

Update the checksum with a single byte. This is where the "rolling" method is used.

Parameters:

b - The next byte.

check

void check(byte[] buf,
           int offset,
           int length)

Replaces the current internal state with entirely new data.

Parameters:

buf - The bytes to checksum.

offset - The offset into buf to start reading.

length - The number of bytes to update.

first

void first(byte[] buf,
           int offset,
           int length)

Replaces the current internal state with entirely new data. This method is only used to initialize rolling checksum.

Parameters:

buf - The bytes to checksum.

offset - The offset into buf to start reading.

length - The number of bytes to update.

clone

Object clone()

Copies this checksum instance into a new instance. This method should be optional, and only implemented if the class implements the Cloneable interface.

Returns:

A clone of this instance.

equals

boolean equals(Object o)

Tests if a particular checksum is equal to this checksum. This means that the other object is an instance of this class, and its internal state equals this checksum's internal state.

Overrides:

equals in class Object

Parameters:

o - The object to test.

Returns:

true if this checksum equals the other checksum.