/*

  * Entagged Audio Tag library

  * Copyright (c) 2004-2005 Christian Laireiter <liree@web.de>

  * 

  * 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 St, Fifth Floor, Boston, MA  02110-1301  USA

  */

 package org.jaudiotagger.audio.asf.io;

 import org.jaudiotagger.audio.asf.data.Chunk;

 import org.jaudiotagger.audio.asf.data.EncryptionChunk;

 import org.jaudiotagger.audio.asf.data.GUID;

 import org.jaudiotagger.audio.asf.util.Utils;

 import java.io.IOException;

 import java.io.InputStream;

 import java.math.BigInteger;

 /**

  * This class reads the chunk containing encoding data <br>

  * <b>Warning:<b><br>

  * Implementation is not completed. More analysis of this chunk is needed.

  * 

  * @author Christian Laireiter

  */

 class EncryptionChunkReader implements ChunkReader {

     /**

      * The GUID this reader {@linkplain #getApplyingIds() applies to}

      */

     private final static GUID[] APPLYING = { GUID.GUID_CONTENT_ENCRYPTION };

     /**

      * Should not be used for now.

      */

     protected EncryptionChunkReader() {

         // NOTHING toDo

     }

     /**

      * {@inheritDoc}

      */

     public boolean canFail() {

         return false;

     }

     /**

      * {@inheritDoc}

      */

     public GUID[] getApplyingIds() {

         return APPLYING.clone();

     }

     /**

      * {@inheritDoc}

      */

     public Chunk read(final GUID guid, final InputStream stream,

             final long chunkStart) throws IOException {

         EncryptionChunk result;

         final BigInteger chunkLen = Utils.readBig64(stream);

         result = new EncryptionChunk(chunkLen);

         // Can't be interpreted

         /*

          * Object ID GUID 128 Object Size QWORD 64 Secret Data Length DWORD 32

          * Secret Data INTEGER varies Protection Type Length DWORD 32 Protection

          * Type char varies Key ID Length DWORD 32 Key ID char varies License

          * URL Length DWORD 32 License URL char varies * Read the

          */

         byte[] secretData;

         byte[] protectionType;

         byte[] keyID;

         byte[] licenseURL;

         // Secret Data length

         int fieldLength;

         fieldLength = (int) Utils.readUINT32(stream);

         // Secret Data

         secretData = new byte[fieldLength + 1];

         stream.read(secretData, 0, fieldLength);

         secretData[fieldLength] = 0;

         // Protection type Length

         fieldLength = 0;

         fieldLength = (int) Utils.readUINT32(stream);

         // Protection Data Length

         protectionType = new byte[fieldLength + 1];

         stream.read(protectionType, 0, fieldLength);

         protectionType[fieldLength] = 0;

         // Key ID length

         fieldLength = 0;

         fieldLength = (int) Utils.readUINT32(stream);

         // Key ID

         keyID = new byte[fieldLength + 1];

         stream.read(keyID, 0, fieldLength);

         keyID[fieldLength] = 0;

         // License URL length

         fieldLength = 0;

         fieldLength = (int) Utils.readUINT32(stream);

         // License URL

         licenseURL = new byte[fieldLength + 1];

         stream.read(licenseURL, 0, fieldLength);

         licenseURL[fieldLength] = 0;

         result.setSecretData(new String(secretData));

         result.setProtectionType(new String(protectionType));

         result.setKeyID(new String(keyID));

         result.setLicenseURL(new String(licenseURL));

         result.setPosition(chunkStart);

         return result;

     }

 }