/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.fs.hfsplus.extent;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import org.apache.log4j.Logger;
import org.jnode.fs.hfsplus.HFSPlusParams;
import org.jnode.fs.hfsplus.HfsPlusFileSystem;
import org.jnode.fs.hfsplus.HfsPlusForkData;
import org.jnode.fs.hfsplus.SuperBlock;
import org.jnode.fs.hfsplus.tree.BTHeaderRecord;
import org.jnode.fs.hfsplus.tree.IndexRecord;
import org.jnode.fs.hfsplus.tree.NodeDescriptor;
import org.jnode.util.ByteBufferUtils;
import org.jnode.util.NumberUtils;
public class Extent {
private final Logger log = Logger.getLogger(getClass());
/**
* B-Tree node descriptor
*/
private NodeDescriptor btnd;
/**
* B-Tree Header record
*/
private BTHeaderRecord bthr;
/**
* The current file system.
*/
private HfsPlusFileSystem fs;
/**
* The extent file data fork.
*/
private HfsPlusForkData extentFile;
private ByteBuffer buffer;
public Extent(HFSPlusParams params) {
log.info("Create B-Tree extent file.");
btnd = new NodeDescriptor(0, 0, NodeDescriptor.BT_HEADER_NODE, 0, 3);
//
int totalNodes = params.getExtentClumpSize() / params.getExtentNodeSize();
int freeNodes = totalNodes - 1;
bthr = new BTHeaderRecord(0, 0, 0, 0, 0, params.getExtentNodeSize(),
ExtentKey.MAXIMUM_KEY_LENGTH, totalNodes, freeNodes,
params.getExtentClumpSize(), BTHeaderRecord.BT_TYPE_HFS,
BTHeaderRecord.KEY_COMPARE_TYPE_CASE_FOLDING,
BTHeaderRecord.BT_BIG_KEYS_MASK);
}
public Extent(HfsPlusFileSystem fs) throws IOException {
log.debug("Load B-Tree extent overflow file.");
this.fs = fs;
SuperBlock sb = fs.getVolumeHeader();
extentFile = sb.getExtentsFile();
if (!extentFile.getExtent(0).isEmpty()) {
buffer = ByteBuffer.allocate(NodeDescriptor.BT_NODE_DESCRIPTOR_LENGTH +
BTHeaderRecord.BT_HEADER_RECORD_LENGTH);
extentFile.read(fs, 0, buffer);
buffer.rewind();
byte[] data = ByteBufferUtils.toArray(buffer);
log.debug("Load extent node descriptor.");
btnd = new NodeDescriptor(data, 0);
log.debug(btnd.toString());
log.debug("Load extent header record.");
bthr = new BTHeaderRecord(data, NodeDescriptor.BT_NODE_DESCRIPTOR_LENGTH);
log.debug(bthr.toString());
}
}
/**
* Gets all overflow extents that match the given key.
*
* @param key the key to match.
* @return the overflow extents.
* @throws IOException if an error occurs.
*/
public final ExtentDescriptor[] getOverflowExtents(final ExtentKey key) throws IOException {
return getOverflowExtents(key, bthr.getRootNode());
}
/**
* Gets all overflow extents that match the given key.
*
* @param key the key to match.
* @param nodeNumber the current node to read from.
* @return the overflow extents.
* @throws IOException if an error occurs.
*/
public final ExtentDescriptor[] getOverflowExtents(final ExtentKey key, long nodeNumber) throws IOException {
try {
long currentNodeNumber = nodeNumber;
int nodeSize = bthr.getNodeSize();
ByteBuffer nodeData = ByteBuffer.allocate(nodeSize);
extentFile.read(fs, (currentNodeNumber * nodeSize), nodeData);
byte[] data = nodeData.array();
NodeDescriptor nd = new NodeDescriptor(data, 0);
if (nd.isIndexNode()) {
ExtentNode extentNode = new ExtentNode(data, nodeSize);
IndexRecord[] records = extentNode.findAll(key);
List<ExtentDescriptor> overflowExtents = new LinkedList<ExtentDescriptor>();
for (IndexRecord record : records) {
Collections.addAll(overflowExtents, getOverflowExtents(key, record.getIndex()));
}
return overflowExtents.toArray(new ExtentDescriptor[overflowExtents.size()]);
} else if (nd.isLeafNode()) {
ExtentLeafNode node = new ExtentLeafNode(nodeData.array(), nodeSize);
return node.getOverflowExtents(key);
} else {
log.info(
String.format("Node %d wasn't a leaf or index: %s\n%s", nodeNumber, nd, NumberUtils.hex(data)));
return new ExtentDescriptor[0];
}
} catch (Exception e) {
e.printStackTrace();
throw new IOException(e);
}
}
}