/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
/* vim:set softtabstop=3 shiftwidth=3 tabstop=3 expandtab tw=72:
$Id: Configuration.java,v 1.9 2003/05/17 09:48:58 rsdio Exp $
Configuration -- Wrapper around configuration data.
Copyright (C) 2003 Casey Marshall <rsdio@metastatic.org>
This file is a part of Jarsync.
Jarsync is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at
your option) any later version.
Jarsync is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with Jarsync; if not, write to the
Free Software Foundation, Inc.,
59 Temple Place, Suite 330,
Boston, MA 02111-1307
USA
Linking Jarsync statically or dynamically with other modules is
making a combined work based on Jarsync. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination. */
package io.milton.zsync;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
* A Configuration is a mere collection of objects and values that
* compose a particular configuration for the algorithm, for example the
* message digest that computes the strong checksum.
*
* <p>Usage of a Configuration involves setting the member fields of
* this object to thier appropriate values; thus, it is up to the
* programmer to specify the {@link #strongSum}, {@link #weakSum},
* {@link #blockLength} and {@link #strongSumLength} to be used. The
* other fields are optional.</p>
*
* @author Casey Marshall
* @version $Revision: 1.9 $
*/
public class Configuration implements Cloneable, java.io.Serializable {
// Constants and variables.
// ------------------------------------------------------------------------
/**
* The default block size.
*/
public static final int BLOCK_LENGTH = 1024;
/**
* The default chunk size.
*/
public static final int CHUNK_SIZE = 32768;
/**
* The message digest that computes the stronger checksum.
*/
public transient MessageDigest strongSum;
/**
* The rolling checksum.
*/
public transient RollingChecksum weakSum;
/**
* The length of blocks to checksum.
*/
public int blockLength;
/**
* The effective length of the strong sum.
*/
public int strongSumLength;
/**
* Whether or not to do run-length encoding when making Deltas.
*/
public boolean doRunLength;
/**
* The seed for the checksum, to perturb the strong checksum and help
* avoid collisions in plain rsync (or in similar applicaitons).
*/
public byte[] checksumSeed;
/**
* The maximum size of byte arrays to create, when they are needed.
* This vale defaults to 32 kilobytes.
*/
public int chunkSize;
// Constructors.
// ------------------------------------------------------------------------
public Configuration() {
blockLength = BLOCK_LENGTH;
chunkSize = CHUNK_SIZE;
}
/**
* Private copying constructor.
*/
private Configuration(Configuration that)
{
try {
this.strongSum = (MessageDigest) (that.strongSum != null
? that.strongSum.clone()
: null);
} catch (CloneNotSupportedException cnse) {
try {
this.strongSum = MessageDigest.getInstance(
that.strongSum.getAlgorithm());
} catch (NoSuchAlgorithmException nsae) {
// Fucked up situation. We die now.
throw new Error(nsae);
}
}
this.weakSum = (RollingChecksum) (that.weakSum != null
? that.weakSum.clone()
: null);
this.blockLength = that.blockLength;
this.doRunLength = that.doRunLength;
this.strongSumLength = that.strongSumLength;
this.checksumSeed = (byte[]) (that.checksumSeed != null
? that.checksumSeed.clone()
: null);
this.chunkSize = that.chunkSize;
}
public int getBlock(){
return blockLength;
}
// Instance methods.
// -----------------------------------------------------------------------
@Override
public Object clone() {
return new Configuration(this);
}
// Serialization methods.
// -----------------------------------------------------------------------
private void writeObject(ObjectOutputStream out) throws IOException {
out.defaultWriteObject();
out.writeUTF(strongSum != null ? strongSum.getAlgorithm() : "NONE");
}
private void readObject(ObjectInputStream in)
throws IOException, ClassNotFoundException
{
in.defaultReadObject();
String s = in.readUTF();
if (!s.equals("NONE")) {
try {
strongSum = MessageDigest.getInstance(s);
} catch (NoSuchAlgorithmException nsae) {
throw new java.io.InvalidObjectException(nsae.getMessage());
}
}
}
}