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package org.openoffice.xmerge.converter.palm;
import java.io.RandomAccessFile;
import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import org.openoffice.xmerge.converter.palm.*;
/**
* <p>Provides functionality to decode a PDB formatted file into
* a <code>PalmDB</code> object given an <code>InputStream</code>.
* This class is only used by the <code>PalmDB</code> object.</p>
*
* <p>Sample usage:</p>
*
* <blockquote><pre><code>
* PdbDecoder decoder = new PdbDecoder("sample.pdb");
* PalmDB palmDB = decoder.parse();
* </code></pre></blockquote>
*
* <p>This decoder has the following assumptions on the PDB file:</p>
*
* <p><ol>
* <li>There is only one RecordList section in the PDB.</li>
* <li>The <code>Record</code> indices in the RecordList are sorted in
* order, i.e. the first <code>Record</code> index refers to
* <code>Record</code> 0, and so forth.</li>
* <li>The raw <code>Record</code> in the <code>Record</code> section
* are sorted as well in order, i.e. first <code>Record</code>
* comes ahead of second <code>Record</code>, etc.</li>
* </ol></p>
*
* <p>Other decoders assume these as well.</p>
*
* @author Herbie Ong
* @see PalmDB
* @see Record
*/
public final class PdbDecoder {
/**
* <p>This method decodes a PDB file into a <code>PalmDB</code>
* object.</p>
*
* <p>First, the header data is read using the <code>PdbHeader</code>
* <code>read</code> method. Next, the RecordList section is
* read and the <code>Record</code> offsets are stored for use when
* parsing the Records. Based on these offsets, the bytes
* corresponding to each <code>Record</code> are read and each is
* stored in a <code>Record</code> object. Lastly, the data is
* used to create a <code>PalmDB</code> object.</p>
*
* @param fileName PDB file name.
*
* @throws IOException If I/O error occurs.
*/
public PalmDB parse(String fileName) throws IOException {
RandomAccessFile file = new RandomAccessFile(fileName, "r");
// read the PDB header
PdbHeader header = new PdbHeader();
header.read(file);
Record recArray[] = new Record[header.numRecords];
if (header.numRecords != 0) {
// read in the record indices + offsets
int recOffset[] = new int[header.numRecords];
byte recAttrs[] = new byte[header.numRecords];
for (int i = 0; i < header.numRecords; i++) {
recOffset[i] = file.readInt();
// read in attributes (1 byte) + unique id (3 bytes)
// take away the unique id, store the attributes
int attr = file.readInt();
recAttrs[i] = (byte) (attr >>> 24);
}
// read the records
int len = 0;
byte[] bytes = null;
int lastIndex = header.numRecords - 1;
for (int i = 0; i < lastIndex; i++) {
file.seek(recOffset[i]);
len = recOffset[i+1] - recOffset[i];
bytes = new byte[len];
file.readFully(bytes);
recArray[i] = new Record(bytes, recAttrs[i]);
}
// last record
file.seek(recOffset[lastIndex]);
len = (int) file.length() - recOffset[lastIndex];
bytes = new byte[len];
file.readFully(bytes);
recArray[lastIndex] = new Record(bytes, recAttrs[lastIndex]);
}
file.close();
// create PalmDB and return it
PalmDB pdb = new PalmDB(header.pdbName, header.creatorID,
header.typeID, header.version, header.attribute, recArray);
return pdb;
}
/**
* <p>This method decodes a PDB file into a <code>PalmDB</code>
* object.</p>
*
* <p>First, the header data is read using the <code>PdbHeader</code>
* <code>read</code> method. Next, the RecordList section is
* read and the <code>Record</code> offsets are stored for use when
* parsing the Records. Based on these offsets, the bytes
* corresponding to each <code>Record</code> are read and each is
* stored in a <code>Record</code> object. Lastly, the data is
* used to create a <code>PalmDB</code> object.</p>
*
* @param b <code>byte[]</code> containing PDB.
*
* @throws IOException If I/O error occurs.
*/
public PalmDB parse(byte[] b) throws IOException {
ByteArrayInputStream bais = new ByteArrayInputStream(b);
DataInputStream dis = new DataInputStream(bais);
// read the PDB header
PdbHeader header = new PdbHeader();
header.read(dis);
Record recArray[] = new Record[header.numRecords];
if (header.numRecords != 0) {
// read in the record indices + offsets
int recOffset[] = new int[header.numRecords];
byte recAttrs[] = new byte[header.numRecords];
for (int i = 0; i < header.numRecords; i++) {
recOffset[i] = dis.readInt();
// read in attributes (1 byte) + unique id (3 bytes)
// take away the unique id, store the attributes
int attr = dis.readInt();
recAttrs[i] = (byte) (attr >>> 24);
}
// read the records
int len = 0;
byte[] bytes = null;
int lastIndex = header.numRecords - 1;
for (int i = 0; i < lastIndex; i++) {
//dis.seek(recOffset[i]);
dis.reset();
dis.skip(recOffset[i]);
len = recOffset[i+1] - recOffset[i];
bytes = new byte[len];
dis.readFully(bytes);
recArray[i] = new Record(bytes, recAttrs[i]);
}
// last record
dis.reset();
len = (int) dis.available() - recOffset[lastIndex];
dis.skip(recOffset[lastIndex]);
bytes = new byte[len];
dis.readFully(bytes);
recArray[lastIndex] = new Record(bytes, recAttrs[lastIndex]);
}
// create PalmDB and return it
PalmDB pdb = new PalmDB(header.pdbName, header.creatorID,
header.typeID, header.version, header.attribute, recArray);
return pdb;
}
}