/**

  *  @author : Paul Taylor

  *  @author : Eric Farng

  *

  *  Version @version:$Id: AbstractID3v1Tag.java 830 2009-11-12 12:23:47Z paultaylor $

  *

  *  MusicTag Copyright (C)2003,2004

  *

  *  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,

  *  you can get a copy from http://www.opensource.org/licenses/lgpl-license.php or write to the Free Software

  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

  *

  * Description:

  * Abstract superclass of all URL Frames

  *

  */

 package org.jaudiotagger.tag.id3;

 import java.io.IOException;

 import java.io.RandomAccessFile;

 import java.nio.ByteBuffer;

 import java.nio.channels.FileChannel;

 import java.util.logging.Logger;

 import java.util.regex.Pattern;

 /**

  * This is the abstract base class for all ID3v1 tags.

  *

  * @author : Eric Farng

  * @author : Paul Taylor

  */

 abstract public class AbstractID3v1Tag extends AbstractID3Tag

 {

     //Logger

     public static Logger logger = Logger.getLogger("org.jaudiotagger.tag.id3");

     public AbstractID3v1Tag()

     {

     }

     public AbstractID3v1Tag(AbstractID3v1Tag copyObject)

     {

         super(copyObject);

     }

     //If field is less than maximum field length this is how it is terminated

     protected static final byte END_OF_FIELD = (byte) 0;

     //Used to detect end of field in String constructed from Data

     protected static Pattern endofStringPattern = Pattern.compile("\\x00");

     //Tag ID as held in file

     protected static final byte[] TAG_ID = {(byte) 'T', (byte) 'A', (byte) 'G'};

     //Fields Lengths common to v1 and v1.1 tags

     protected static final int TAG_LENGTH = 128;

     protected static final int TAG_DATA_LENGTH = 125;

     protected static final int FIELD_TAGID_LENGTH = 3;

     protected static final int FIELD_TITLE_LENGTH = 30;

     protected static final int FIELD_ARTIST_LENGTH = 30;

     protected static final int FIELD_ALBUM_LENGTH = 30;

     protected static final int FIELD_YEAR_LENGTH = 4;

     protected static final int FIELD_GENRE_LENGTH = 1;

     //Field Positions, starting from zero so fits in with Java Terminology

     protected static final int FIELD_TAGID_POS = 0;

     protected static final int FIELD_TITLE_POS = 3;

     protected static final int FIELD_ARTIST_POS = 33;

     protected static final int FIELD_ALBUM_POS = 63;

     protected static final int FIELD_YEAR_POS = 93;

     protected static final int FIELD_GENRE_POS = 127;

     //For writing output

     protected static final String TYPE_TITLE = "title";

     protected static final String TYPE_ARTIST = "artist";

     protected static final String TYPE_ALBUM = "album";

     protected static final String TYPE_YEAR = "year";

     protected static final String TYPE_GENRE = "genre";

     /**

      * Return the size of this tag, the size is fixed for tags of this type

      *

      * @return size of this tag in bytes

      */

     public int getSize()

     {

         return TAG_LENGTH;

     }

     /**

      * Delete tag from file

      * Looks for tag and if found lops it off the file.

      *

      * @param file to delete the tag from

      * @throws IOException if there was a problem accessing the file

      */

     public void delete(RandomAccessFile file) throws IOException

     {

         //Read into Byte Buffer

         logger.info("Deleting ID3v1 from file if exists");

         FileChannel fc;

         ByteBuffer byteBuffer;

         fc = file.getChannel();

         fc.position(file.length() - TAG_LENGTH);

         byteBuffer = ByteBuffer.allocate(TAG_LENGTH);

         fc.read(byteBuffer);

         byteBuffer.rewind();

         if (seek(byteBuffer))

         {

             logger.info("Deleted ID3v1 tag ");

             file.setLength(file.length() - TAG_LENGTH);

         }

         else

         {

             logger.info("Unable to find ID3v1 tag to deleteField");

         }

     }

 }