/*
* $Id$
*
* 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.catalog;
import org.jnode.fs.hfsplus.HfsUnicodeString;
import org.jnode.fs.hfsplus.tree.AbstractKey;
import org.jnode.fs.hfsplus.tree.Key;
import org.jnode.util.BigEndian;
/**
* Implementation of catalog file key. The catalog file key is defined as following :
* <ul>
* <li>The length of the key</li>
* <li>The node identifier of the parent folder</li>
* <li>The name of the file or folder</li>
* </ul>
*
* The minimal length for a key is 6 bytes. 2 bytes for the length and 4 bytes for the catalog node id.
*
*/
public class CatalogKey extends AbstractKey {
public static final int MINIMUM_KEY_LENGTH = 6;
public static final int MAXIMUM_KEY_LENGTH = 516;
/**
* Catalog node id of the folder that contains file or folder represented by
* the record. For thread records, contains the catalog node id of the file
* or folder itself.
*/
private CatalogNodeId parentId;
/**
* Name of the file or folder, empty for thread records.
*/
private HfsUnicodeString nodeName;
/**
* Create catalog key from existing data.
*
* @param src
* @param offset
*/
public CatalogKey(final byte[] src, final int offset) {
int currentOffset = offset;
byte[] ck = new byte[2];
System.arraycopy(src, currentOffset, ck, 0, 2);
//TODO Understand why the +2 is necessary
keyLength = BigEndian.getInt16(ck, 0) + 2;
currentOffset += 2;
ck = new byte[4];
System.arraycopy(src, currentOffset, ck, 0, 4);
parentId = new CatalogNodeId(ck, 0);
currentOffset += 4;
if (keyLength > MINIMUM_KEY_LENGTH) {
nodeName = new HfsUnicodeString(src, currentOffset);
}
}
/**
* Create new catalog key based on parent CNID, ignoring file/folder name.
*
* @param parentID Parent catalog node identifier.
*/
public CatalogKey(CatalogNodeId parentID) {
this(parentID, new HfsUnicodeString(""));
}
/**
* Create new catalog key based on parent CNID and the name of the file or
* folder.
*
* @param parentID Parent catalog node identifier.
* @param name Name of the file or folder.
*
*/
public CatalogKey(final CatalogNodeId parentID, final HfsUnicodeString name) {
this.parentId = parentID;
this.nodeName = name;
this.keyLength = MINIMUM_KEY_LENGTH + (name.getLength() * 2) + 2;
}
public final CatalogNodeId getParentId() {
return parentId;
}
public final HfsUnicodeString getNodeName() {
return nodeName;
}
/**
* Compare two catalog keys. These keys are compared by parent id and next
* by node name.
*
* @param key
*
*/
public final int compareTo(final Key key) {
int res = -1;
if (key instanceof CatalogKey) {
CatalogKey ck = (CatalogKey) key;
res = this.getParentId().compareTo(ck.getParentId());
if (res == 0) {
// Note: this is unlikely to be correct. See TN1150 section "Unicode Subtleties" for details
// For reading in data is should be safe since the B-Tree will be pre-sorted, but for adding new entries
// it will cause the order to be wrong.
res = this.getNodeName().getUnicodeString()
.compareTo(ck.getNodeName().getUnicodeString());
}
}
return res;
}
@Override
public int hashCode() {
return 73 ^ parentId.hashCode();
}
@Override
public boolean equals(Object obj) {
if (!(obj instanceof CatalogKey)) {
return false;
}
CatalogKey otherKey = (CatalogKey) obj;
return parentId.getId() == otherKey.parentId.getId();
}
/*
* (non-Javadoc)
*
* @see org.jnode.fs.hfsplus.tree.AbstractKey#getBytes()
*/
public byte[] getBytes() {
int length = this.getKeyLength();
byte[] data = new byte[length];
BigEndian.setInt16(data, 0, length);
System.arraycopy(parentId.getBytes(), 0, data, 2, 4);
System.arraycopy(nodeName.getBytes(), 0, data, 6, (nodeName.getLength() * 2) + 2);
return data;
}
/*
* (non-Javadoc)
*
* @see java.lang.Object#toString()
*/
public final String toString() {
StringBuffer s = new StringBuffer();
s.append("[length, Parent ID, Node name]:").append(getKeyLength()).append(",")
.append(getParentId().getId()).append(",")
.append((getNodeName() != null) ? getNodeName().getUnicodeString() : "");
return s.toString();
}
}