org.metastatic.rsync
Interface RollingChecksum

All Superinterfaces:

Cloneable, Serializable

All Known Implementing Classes:

Checksum32

public interface RollingChecksum

extends Cloneable, Serializable

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

Method Summary

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.
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 bt) Update the checksum with a single byte.
void	trim() Update the checksum by simply "trimming" the least-recently-updated byte from the internal state.

Method Detail

getValue

public int getValue()

Returns the currently-computed 32-bit checksum.

Returns:

The checksum.

reset

public void reset()

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

roll

public void roll(byte bt)

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

Parameters:

bt - The next byte.

trim

public void trim()

Update the checksum by simply "trimming" the least-recently-updated byte from the internal state. Most, but not all, checksums can support this.

check

public 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.

clone

public 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

public 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.