public void WriteMetadata(Stream stream, MetadataDictionary metadata, SettingsDictionary settings)
{
bool usePadding;
if (string.IsNullOrEmpty(settings["UsePadding"]))
{
usePadding = false;
}
else if (!bool.TryParse(settings["UsePadding"], out usePadding))
{
throw new InvalidSettingException(string.Format(CultureInfo.CurrentCulture,
Resources.MetadataEncoderBadUsePadding, settings["UsePadding"]));
}
NativeVorbisCommentBlock vorbisCommentBlock = null;
NativePictureBlock pictureBlock = null;
try
{
using (var chain = new NativeMetadataChain(stream))
{
if (!chain.Read())
{
MetadataChainStatus chainStatus = chain.GetStatus();
if (chainStatus == MetadataChainStatus.NotAFlacFile)
{
throw new UnsupportedAudioException(Resources.MetadataEncoderNotFlacError);
}
else
{
throw new IOException(string.Format(CultureInfo.CurrentCulture,
Resources.MetadataEncoderReadError, chainStatus));
}
}
// Create a Vorbis Comment block, even if empty:
vorbisCommentBlock = new NativeVorbisCommentBlock();
foreach (var item in new MetadataToVorbisCommentAdapter(metadata))
{
vorbisCommentBlock.Append(item.Key, item.Value);
}
// Create a Picture block if cover art is available:
if (metadata.CoverArt != null)
{
pictureBlock = new CoverArtToPictureBlockAdapter(metadata.CoverArt);
}
// Iterate over the existing blocks, replacing and deleting as needed:
using (var iterator = new NativeMetadataIterator(chain.Handle))
UpdateMetadata(iterator, vorbisCommentBlock, pictureBlock);
if (chain.CheckIfTempFileNeeded(usePadding))
{
// If FLAC requests a temporary file, use a MemoryStream instead. Then overwrite the original:
using (var tempStream = new MemoryStream())
{
if (!chain.WriteWithTempFile(usePadding, tempStream))
{
throw new IOException(string.Format(CultureInfo.CurrentCulture,
Resources.MetadataEncoderTempFileError, chain.GetStatus()));
}
// Clear the original stream, and copy the temporary one over it:
stream.SetLength(tempStream.Length);
stream.Position = 0;
tempStream.WriteTo(stream);
}
}
else if (!chain.Write(usePadding))
{
throw new IOException(string.Format(CultureInfo.CurrentCulture,
Resources.MetadataEncoderWriteError, chain.GetStatus()));
}
}
}
finally
{
vorbisCommentBlock?.Dispose();
pictureBlock?.Dispose();
}
}
static void UpdateMetadata(NativeMetadataIterator iterator, NativeVorbisCommentBlock newComments, NativePictureBlock newPicture)
{
Contract.Requires(iterator != null);
Contract.Requires(newComments != null);
var metadataInserted = false;
var pictureInserted = false;
do
{
switch ((MetadataType)Marshal.ReadInt32(iterator.GetBlock()))
{
// Replace the existing Vorbis comment:
case MetadataType.VorbisComment:
if (!iterator.DeleteBlock(false))
{
throw new IOException(Resources.MetadataEncoderDeleteError);
}
if (!iterator.InsertBlockAfter(newComments.Handle))
{
throw new IOException(Resources.MetadataEncoderInsertBlockError);
}
metadataInserted = true;
break;
// Replace the existing Picture block:
case MetadataType.Picture:
if (!iterator.DeleteBlock(false))
{
throw new IOException(Resources.MetadataEncoderDeleteError);
}
if (newPicture != null && !iterator.InsertBlockAfter(newPicture.Handle))
{
throw new IOException(Resources.MetadataEncoderInsertBlockError);
}
pictureInserted = true;
break;
// Delete any padding:
case MetadataType.Padding:
if (!iterator.DeleteBlock(false))
{
throw new IOException(Resources.MetadataEncoderDeleteError);
}
break;
}
} while (iterator.Next());
// If there was no existing metadata block to replace, insert it now:
if (!metadataInserted && !iterator.InsertBlockAfter(newComments.Handle))
{
throw new IOException(Resources.MetadataEncoderInsertBlockError);
}
// If there was no existing picture block to replace, and a new one is available, insert it now:
if (newPicture != null && !pictureInserted && !iterator.InsertBlockAfter(newPicture.Handle))
{
throw new IOException(Resources.MetadataEncoderInsertBlockError);
}
newComments.ReleaseHandleOwnership();
newPicture?.ReleaseHandleOwnership();
}