/*

  * 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.ContentDescription;

 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;

 /**

  * Reads and interprets the data of a ASF chunk containing title, author... <br>

  * 

  * @author Christian Laireiter

  * @see org.jaudiotagger.audio.asf.data.ContentDescription

  */

 public class ContentDescriptionReader implements ChunkReader {

     /**

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

      */

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

     /**

      * Should not be used for now.

      */

     protected ContentDescriptionReader() {

         // NOTHING toDo

     }

     /**

      * {@inheritDoc}

      */

     public boolean canFail() {

         return false;

     }

     /**

      * {@inheritDoc}

      */

     public GUID[] getApplyingIds() {

         return APPLYING.clone();

     }

     /**

      * Returns the next 5 UINT16 values as an array.<br>

      * 

      * @param stream

      *            stream to read from

      * @return 5 int values read from stream.

      * @throws IOException

      *             on I/O Errors.

      */

     private int[] getStringSizes(final InputStream stream) throws IOException {

         final int[] result = new int[5];

         for (int i = 0; i < result.length; i++) {

             result[i] = Utils.readUINT16(stream);

         }

         return result;

     }

     /**

      * {@inheritDoc}

      */

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

             final long chunkStart) throws IOException {

         final BigInteger chunkSize = Utils.readBig64(stream);

         /*

          * Now comes 16-Bit values representing the length of the Strings which

          * follows.

          */

         final int[] stringSizes = getStringSizes(stream);

         /*

          * Now we know the String length of each occuring String.

          */

         final String[] strings = new String[stringSizes.length];

         for (int i = 0; i < strings.length; i++) {

             if (stringSizes[i] > 0) {

                 strings[i] = Utils

                         .readFixedSizeUTF16Str(stream, stringSizes[i]);

             }

         }

         /*

          * Now create the result

          */

         final ContentDescription result = new ContentDescription(chunkStart,

                 chunkSize);

         if (stringSizes[0] > 0) {

             result.setTitle(strings[0]);

         }

         if (stringSizes[1] > 0) {

             result.setAuthor(strings[1]);

         }

         if (stringSizes[2] > 0) {

             result.setCopyright(strings[2]);

         }

         if (stringSizes[3] > 0) {

             result.setComment(strings[3]);

         }

         if (stringSizes[4] > 0) {

             result.setRating(strings[4]);

         }

         return result;

     }

 }