You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
94 lines
3.0 KiB
94 lines
3.0 KiB
// CachedFileReader.java
|
|
// ---------------------
|
|
// (C) 2009 by Michael Peter Christen; mc@yacy.net
|
|
// first published 09.09.2009 on http://yacy.net
|
|
//
|
|
// 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
|
|
|
|
|
|
package net.yacy.kelondro.io;
|
|
|
|
import java.io.File;
|
|
import java.io.FileNotFoundException;
|
|
import java.io.IOException;
|
|
import java.io.RandomAccessFile;
|
|
|
|
import net.yacy.kelondro.logging.Log;
|
|
import net.yacy.kelondro.util.MemoryControl;
|
|
|
|
|
|
public final class CachedFileReader extends AbstractReader implements Reader {
|
|
|
|
private final RandomAccessFile RAFile;
|
|
private byte[] cache;
|
|
private final int cachelen;
|
|
|
|
public CachedFileReader(final File file) throws IOException, FileNotFoundException {
|
|
this.name = file.getName();
|
|
this.file = file;
|
|
this.RAFile = new RandomAccessFile(this.file, "r");
|
|
if (MemoryControl.available() / 10L > this.RAFile.length() && this.RAFile.length() < (long) Integer.MAX_VALUE) {
|
|
this.cache = new byte[(int) this.RAFile.length()];
|
|
this.RAFile.seek(0);
|
|
this.RAFile.readFully(this.cache);
|
|
} else {
|
|
this.cache = null;
|
|
}
|
|
this.cachelen = 0;
|
|
}
|
|
|
|
public final synchronized long available() throws IOException {
|
|
return this.length() - RAFile.getFilePointer();
|
|
}
|
|
|
|
public final synchronized long length() throws IOException {
|
|
return this.RAFile.length();
|
|
}
|
|
|
|
public final synchronized void readFully(final byte[] b, final int off, int len) throws IOException {
|
|
long seek = RAFile.getFilePointer();
|
|
if (cache != null && cachelen - seek >= len) {
|
|
// read from cache
|
|
System.arraycopy(cache, (int) (seek), b, off, len);
|
|
RAFile.seek(seek + len);
|
|
return;
|
|
}
|
|
// cannot use the cache
|
|
RAFile.readFully(b, off, len);
|
|
return;
|
|
}
|
|
|
|
public final synchronized void seek(final long pos) throws IOException {
|
|
RAFile.seek(pos);
|
|
}
|
|
|
|
public final synchronized void close() {
|
|
if (RAFile != null) try {
|
|
try{RAFile.getChannel().close();} catch (IOException e) {}
|
|
RAFile.close();
|
|
} catch (IOException e) {
|
|
Log.logException(e);
|
|
}
|
|
this.cache = null;
|
|
}
|
|
|
|
@Override
|
|
protected void finalize() throws Throwable {
|
|
this.close();
|
|
super.finalize();
|
|
}
|
|
|
|
}
|