protected ByteVector FieldData(ByteVector frameData, int offset, byte version)
{
if (frameData == null)
{
throw new ArgumentNullException("frameData");
}
int data_offset = offset + (int)FrameHeader.Size(version);
int data_length = (int)Size;
/*int uncompressed_data_length;*/
if ((Flags & (FrameFlags.Compression | FrameFlags.DataLengthIndicator)) != 0)
{
/*uncompressed_data_length = (int) frame_data.Mid (data_offset, 4).ToUInt () + 4;*/
data_offset += 4;
data_offset -= 4;
}
if ((Flags & FrameFlags.GroupingIdentity) != 0)
{
group_id = frameData [data_offset++];
data_length--;
}
if ((Flags & FrameFlags.Encryption) != 0)
{
encryption_id = frameData [data_offset++];
data_length--;
}
if (data_length > frameData.Count - data_offset)
{
throw new CorruptFileException("Frame size exceeds bounds.");
}
if (data_length < 0)
{
throw new CorruptFileException("Frame size less than zero.");
}
ByteVector data = frameData.Mid(data_offset, data_length);
if ((Flags & FrameFlags.Unsychronisation) != 0)
{
SynchData.ResynchByteVector(data);
}
// FIXME: Implement encryption.
if ((Flags & FrameFlags.Encryption) != 0)
{
throw new NotImplementedException();
}
// FIXME: Implement compression.
if ((Flags & FrameFlags.Compression) != 0)
{
throw new NotImplementedException();
}
/*
* if(d->header->compression()) {
* ByteVector data(frameDataLength);
* uLongf uLongTmp = frameDataLength;
* ::uncompress((Bytef *) data.data(),
* (uLongf *) &uLongTmp,
* (Bytef *) frameData.data() + frameDataOffset,
* size());
* return data;
* }
*/
return(data);
}
//////////////////////////////////////////////////////////////////////////
// public members
//////////////////////////////////////////////////////////////////////////
public static Frame CreateFrame(ByteVector data, ref int offset, byte version)
{
int position = offset;
FrameHeader header = new FrameHeader(data.Mid(position, (int)FrameHeader.Size(version)), version);
offset += (int)(header.FrameSize + FrameHeader.Size(version));
if (header.FrameId == null)
{
throw new System.NotImplementedException();
}
foreach (byte b in header.FrameId)
{
char c = (char)b;
if ((c < 'A' || c > 'Z') && (c < '1' || c > '9'))
{
return(null);
}
}
// Windows Media Player may create zero byte frames. Just send them
// off as unknown and delete them.
if (header.FrameSize == 0)
{
header.Flags |= FrameFlags.TagAlterPreservation;
return(new UnknownFrame(data, position, header, version));
}
// TODO: Support Compression.
if ((header.Flags & FrameFlags.Compression) != 0)
{
throw new System.NotImplementedException();
}
// TODO: Support Encryption.
if ((header.Flags & FrameFlags.Encryption) != 0)
{
throw new System.NotImplementedException();
}
foreach (FrameCreator creator in frame_creators)
{
Frame frame = creator(data, position, header, version);
if (frame != null)
{
return(frame);
}
}
// This is where things get necissarily nasty. Here we determine which
// Frame subclass (or if none is found simply an Frame) based
// on the frame ID. Since there are a lot of possibilities, that means
// a lot of if blocks.
// Text Identification (frames 4.2)
if (header.FrameId == FrameType.TXXX)
{
return(new UserTextInformationFrame(data, position, header, version));
}
if (header.FrameId [0] == (byte)'T')
{
return(new TextInformationFrame(data, position, header, version));
}
// Unique File Identifier (frames 4.1)
if (header.FrameId == FrameType.UFID)
{
return(new UniqueFileIdentifierFrame(data, position, header, version));
}
// Music CD Identifier (frames 4.5)
if (header.FrameId == FrameType.MCDI)
{
return(new MusicCdIdentifierFrame(data, position, header, version));
}
// Unsynchronized Lyrics (frames 4.8)
if (header.FrameId == FrameType.USLT)
{
return(new UnsynchronisedLyricsFrame(data, position, header, version));
}
// Synchronized Lyrics (frames 4.9)
if (header.FrameId == FrameType.SYLT)
{
return(new SynchronisedLyricsFrame(data, position, header, version));
}
// Comments (frames 4.10)
if (header.FrameId == FrameType.COMM)
{
return(new CommentsFrame(data, position, header, version));
}
// Relative Volume Adjustment (frames 4.11)
if (header.FrameId == FrameType.RVA2)
{
return(new RelativeVolumeFrame(data, position, header, version));
}
// Attached Picture (frames 4.14)
if (header.FrameId == FrameType.APIC)
{
return(new AttachedPictureFrame(data, position, header, version));
}
// General Encapsulated Object (frames 4.15)
if (header.FrameId == FrameType.GEOB)
{
return(new GeneralEncapsulatedObjectFrame(data, position, header, version));
}
// Play Count (frames 4.16)
if (header.FrameId == FrameType.PCNT)
{
return(new PlayCountFrame(data, position, header, version));
}
// Play Count (frames 4.17)
if (header.FrameId == FrameType.POPM)
{
return(new PopularimeterFrame(data, position, header, version));
}
// Terms of Use (frames 4.22)
if (header.FrameId == FrameType.USER)
{
return(new TermsOfUseFrame(data, position, header, version));
}
// Private (frames 4.27)
if (header.FrameId == FrameType.PRIV)
{
return(new PrivateFrame(data, position, header, version));
}
return(new UnknownFrame(data, position, header, version));
}
