// kelondroCachedRA.java
// -----------------------
// part of The Kelondro Database
// (C) by Michael Peter Christen; mc@anomic.de
// first published on http://www.anomic.de
// Frankfurt, Germany, 2004, 2005
// last major change: 06.10.2004
// this file was previously named kelondroBufferedRA
//
// This program 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.
//
// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// Using this software in any meaning (reading, learning, copying, compiling,
// running) means that you agree that the Author(s) is (are) not responsible
// for cost, loss of data or any harm that may be caused directly or indirectly
// by usage of this softare or this documentation. The usage of this software
// is on your own risk. The installation and usage (starting/running) of this
// software may allow other people or application to access your computer and
// any attached devices and is highly dependent on the configuration of the
// software which must be done by the user of the software; the author(s) is
// (are) also not responsible for proper configuration and usage of the
// software, even if provoked by documentation provided together with
// the software.
//
// Any changes to this file according to the GPL as documented in the file
// gpl.txt aside this file in the shipment you received can be done to the
// lines that follows this copyright notice here, but changes must not be
// done inside the copyright notive above. A re-distribution must contain
// the intact and unchanged copyright notice.
// Contributions and changes to the program code must be marked as such.
package de.anomic.kelondro;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
public class kelondroCachedRA extends kelondroAbstractRA implements kelondroRA {
protected kelondroRA ra;
protected kelondroMScoreCluster cacheScore;
protected HashMap cacheMemory;
private int cacheMaxElements;
private int cacheElementSize;
private long seekpos;
public kelondroCachedRA(kelondroRA ra, int cachesize, int elementsize) throws FileNotFoundException {
this.ra = ra;
this.name = ra.name();
this.cacheMemory = new HashMap();
this.cacheScore = new kelondroMScoreCluster();
this.cacheElementSize = elementsize;
this.cacheMaxElements = (int) (cachesize / cacheElementSize);
this.seekpos = 0;
}
private int cacheElementNumber(long address) {
return (int) address / cacheElementSize;
}
private int cacheElementOffset(long address) {
return (int) address % cacheElementSize;
}
private byte[] readCache(int cacheNr) throws IOException {
Integer cacheNrI = new Integer(cacheNr);
byte[] cache = (byte[]) cacheMemory.get(cacheNrI);
if (cache == null) {
if (cacheMemory.size() >= cacheMaxElements) {
// delete elements in buffer if buffer too big
Iterator it = cacheScore.scores(true);
Integer element = (Integer) it.next();
writeCache((byte[]) cacheMemory.get(element), element.intValue());
cacheMemory.remove(element);
int age = cacheScore.deleteScore(element);
de.anomic.server.logging.serverLog.logFine("CACHE: " + name, "GC; age=" + ((((int) (0xFFFFFFFFL & System.currentTimeMillis())) - age) / 1000));
}
// add new element
cache = new byte[cacheElementSize];
//System.out.println("buffernr=" + bufferNr + ", elSize=" + bufferElementSize);
ra.seek(cacheNr * cacheElementSize);
ra.read(cache, 0, cacheElementSize);
cacheMemory.put(cacheNrI, cache);
}
cacheScore.setScore(cacheNrI, (int) (0xFFFFFFFFL & System.currentTimeMillis()));
return cache;
}
private void writeCache(byte[] cache, int cacheNr) throws IOException {
if (cache == null) return;
Integer cacheNrI = new Integer(cacheNr);
ra.seek(cacheNr * cacheElementSize);
ra.write(cache, 0, cacheElementSize);
cacheScore.setScore(cacheNrI, (int) (0xFFFFFFFFL & System.currentTimeMillis()));
}
// pseudo-native method read
public int read() throws IOException {
int bn = cacheElementNumber(seekpos);
int offset = cacheElementOffset(seekpos);
seekpos++;
return 0xFF & readCache(bn)[offset];
}
// pseudo-native method write
public void write(int b) throws IOException {
int bn = cacheElementNumber(seekpos);
int offset = cacheElementOffset(seekpos);
byte[] cache = readCache(bn);
seekpos++;
cache[offset] = (byte) b;
//writeBuffer(buffer, bn);
}
public int read(byte[] b, int off, int len) throws IOException {
int bn1 = cacheElementNumber(seekpos);
int bn2 = cacheElementNumber(seekpos + len - 1);
int offset = cacheElementOffset(seekpos);
byte[] buffer = readCache(bn1);
if (bn1 == bn2) {
// simple case
//System.out.println("C1: bn1=" + bn1 + ", offset=" + offset + ", off=" + off + ", len=" + len);
System.arraycopy(buffer, offset, b, off, len);
seekpos += len;
return len;
} else {
// do recursively
int thislen = cacheElementSize - offset;
//System.out.println("C2: bn1=" + bn1 + ", bn2=" + bn2 +", offset=" + offset + ", off=" + off + ", len=" + len + ", thislen=" + thislen);
System.arraycopy(buffer, offset, b, off, thislen);
seekpos += thislen;
return thislen + read(b, off + thislen, len - thislen);
}
}
public void write(byte[] b, int off, int len) throws IOException {
int bn1 = cacheElementNumber(seekpos);
int bn2 = cacheElementNumber(seekpos + len - 1);
int offset = cacheElementOffset(seekpos);
byte[] cache = readCache(bn1);
if (bn1 == bn2) {
// simple case
System.arraycopy(b, off, cache, offset, len);
seekpos += len;
//writeBuffer(buffer, bn1);
} else {
// do recursively
int thislen = cacheElementSize - offset;
System.arraycopy(b, off, cache, offset, thislen);
seekpos += thislen;
//writeBuffer(buffer, bn1);
write(b, off + thislen, len - thislen);
}
}
public void seek(long pos) throws IOException {
seekpos = pos;
}
public void close() throws IOException {
// write all unwritten buffers
if (cacheMemory == null) return;
Iterator it = cacheScore.scores(true);
while (it.hasNext()) {
Integer element = (Integer) it.next();
writeCache((byte[]) cacheMemory.get(element), element.intValue());
cacheMemory.remove(element);
}
ra.close();
cacheScore = null;
cacheMemory = null;
}
public void finalize() {
try {
close();
} catch (IOException e) {}
}
}