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/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0 .
*/
package org.openoffice.xmerge.converter.palm;
import java.io.IOException;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
/**
* Provides functionality to decode a PDB formatted file into a {@code PalmDB}
* object given an {@code InputStream}.
*
* <p>This class is only used by the {@code PalmDB} object.</p>
*
* <p>Sample usage:</p>
* <blockquote><pre>{@code PdbDecoder decoder = new PdbDecoder("sample.pdb");
* PalmDB palmDB = decoder.parse();}</pre></blockquote>
*
* <p>This decoder has the following assumptions on the PDB file:</p>
* <ol>
* <li>There is only one RecordList section in the PDB.</li>
* <li>The {@code Record} indices in the RecordList are sorted in order, i.e.
* the first {@code Record} index refers to {@code Record} 0, and so
* forth.</li>
* <li>The raw {@code Record} in the {@code Record} section are sorted as
* well in order, i.e. first {@code Record} comes ahead of second
* {@code Record}, etc.</li>
* </ol>
*
* <p>Other decoders assume these as well.</p>
*
* @see PalmDB
* @see Record
*/
public final class PdbDecoder {
/**
* This method decodes a PDB file into a {@code PalmDB} object.
*
* <p>First, the header data is read using the {@code PdbHeader.read}
* method. Next, the RecordList section is read and the {@code Record}
* offsets are stored for use when parsing the Records. Based on these
* offsets, the bytes corresponding to each {@code Record} are read and
* each is stored in a {@code Record} object. Lastly, the data is used
* to create a {@code PalmDB} object.</p>
*
* @param b {@code byte[]} 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 lastIndex = header.numRecords - 1;
for (int i = 0; i < lastIndex; i++) {
//dis.seek(recOffset[i]);
dis.reset();
dis.skip(recOffset[i]);
int len = recOffset[i+1] - recOffset[i];
byte[] bytes = new byte[len];
dis.readFully(bytes);
recArray[i] = new Record(bytes, recAttrs[i]);
}
// last record
dis.reset();
int len = dis.available() - recOffset[lastIndex];
dis.skip(recOffset[lastIndex]);
byte[] 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;
}
}
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