/*
* Entagged Audio Tag library
* Copyright (c) 2003-2005 Raphaƫl Slinckx <raphael@slinckx.net>
* 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.tag.vorbiscomment;
import org.jaudiotagger.audio.exceptions.CannotReadException;
import org.jaudiotagger.audio.generic.Utils;
import org.jaudiotagger.audio.ogg.util.VorbisHeader;
import org.jaudiotagger.logging.ErrorMessage;
import java.io.IOException;
import java.util.logging.Logger;
/**
* Create the VorbisCommentTag by reading from the raw packet data
* <p/>
* <p>This is in the same format whether encoded with Ogg or Flac
* except the framing bit is only present when used within Ogg Vorbis
* <p/>
* <pre>
* From the http://xiph.org/vorbis/doc/Vorbis_I_spec.html#vorbis-spec-comment
* Read decodes the packet data using the following algorithm:
* [vendor_length] = read an unsigned integer of 32 bits
* [vendor_string] = read a UTF-8 vector as [vendor_length] octets
* [user_comment_list_length] = read an unsigned integer of 32 bits
* iterate [user_comment_list_length] times {
* 5) [length] = read an unsigned integer of 32 bits
* 6) this iteration's user comment = read a UTF-8 vector as [length] octets
* }
* [framing_bit] = read a single bit as boolean
* if ( [framing_bit] unset or end-of-packet ) then ERROR
* done.
* </pre>
*/
public class VorbisCommentReader
{
// Logger Object
public static Logger logger = Logger.getLogger("org.jaudiotagger.tag.vorbiscomment.VorbisCommentReader");
public static final int FIELD_VENDOR_LENGTH_POS = 0;
public static final int FIELD_VENDOR_STRING_POS = 4;
public static final int FIELD_VENDOR_LENGTH_LENGTH = 4;
public static final int FIELD_USER_COMMENT_LIST_LENGTH = 4;
public static final int FIELD_COMMENT_LENGTH_LENGTH = 4;
/**
* max comment length that jaudiotagger can handle, this isnt the maximum column length allowed but we dont
* dont allow comments larger than this because of problem with allocating memory (10MB shoudl be fine for all apps)
*/
private static final int JAUDIOTAGGER_MAX_COMMENT_LENGTH = 10000000;
public VorbisCommentReader()
{
}
/**
* @param rawdata
* @param isFramingBit
* @return logical representation of VorbisCommentTag
* @throws IOException
* @throws CannotReadException
*/
public VorbisCommentTag read(byte[] rawdata, boolean isFramingBit) throws IOException, CannotReadException
{
VorbisCommentTag tag = new VorbisCommentTag();
byte[] b = new byte[FIELD_VENDOR_LENGTH_LENGTH];
System.arraycopy(rawdata, FIELD_VENDOR_LENGTH_POS, b, FIELD_VENDOR_LENGTH_POS, FIELD_VENDOR_LENGTH_LENGTH);
int pos = FIELD_VENDOR_LENGTH_LENGTH;
int vendorStringLength = Utils.getIntLE(b);
b = new byte[vendorStringLength];
System.arraycopy(rawdata, pos, b, 0, vendorStringLength);
pos += vendorStringLength;
tag.setVendor(new String(b, VorbisHeader.CHARSET_UTF_8));
logger.config("Vendor is:"+tag.getVendor());
b = new byte[FIELD_USER_COMMENT_LIST_LENGTH];
System.arraycopy(rawdata, pos, b, 0, FIELD_USER_COMMENT_LIST_LENGTH);
pos += FIELD_USER_COMMENT_LIST_LENGTH;
int userComments = Utils.getIntLE(b);
logger.config("Number of user comments:" + userComments);
for (int i = 0; i < userComments; i++)
{
b = new byte[FIELD_COMMENT_LENGTH_LENGTH];
System.arraycopy(rawdata, pos, b, 0, FIELD_COMMENT_LENGTH_LENGTH);
pos += FIELD_COMMENT_LENGTH_LENGTH;
int commentLength = Utils.getIntLE(b);
logger.config("Next Comment Length:" + commentLength);
if(commentLength> JAUDIOTAGGER_MAX_COMMENT_LENGTH)
{
logger.warning(ErrorMessage.VORBIS_COMMENT_LENGTH_TOO_LARGE.getMsg(commentLength));
break;
}
else if(commentLength>rawdata.length)
{
logger.warning(ErrorMessage.VORBIS_COMMENT_LENGTH_LARGE_THAN_HEADER.getMsg(commentLength,rawdata.length));
break;
}
else
{
b = new byte[commentLength];
System.arraycopy(rawdata, pos, b, 0, commentLength);
pos += commentLength;
VorbisCommentTagField fieldComment = new VorbisCommentTagField(b);
logger.config("Adding:" + fieldComment.getId());
tag.addField(fieldComment);
}
}
//Check framing bit, only exists when vorbisComment used within OggVorbis
if (isFramingBit)
{
if ((rawdata[pos] & 0x01) != 1)
{
throw new CannotReadException(ErrorMessage.OGG_VORBIS_NO_FRAMING_BIT.getMsg((rawdata[pos] & 0x01)));
}
}
return tag;
}
}
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