/*

  * 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.EncodingChunk;

 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 EncodingChunkReader implements ChunkReader {

     /**

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

      */

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

     /**

      * Should not be used for now.

      */

     protected EncodingChunkReader() {

         // 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 {

         final BigInteger chunkLen = Utils.readBig64(stream);

         final EncodingChunk result = new EncodingChunk(chunkLen);

         int readBytes = 24;

         // Can't be interpreted

         /*

          * What do I think of this data, well it seems to be another GUID. Then

          * followed by a UINT16 indicating a length of data following (by half).

          * My test files just had the length of one and a two bytes zero.

          */

         stream.skip(20);

         readBytes += 20;

         /*

          * Read the number of strings which will follow

          */

         final int stringCount = Utils.readUINT16(stream);

         readBytes += 2;

         /*

          * Now reading the specified amount of strings.

          */

         for (int i = 0; i < stringCount; i++) {

             final String curr = Utils.readCharacterSizedString(stream);

             result.addString(curr);

             readBytes += 4 + 2 * curr.length();

         }

         stream.skip(chunkLen.longValue() - readBytes);

         result.setPosition(chunkStart);

         return result;

     }

 }