/// <summary>
/// Determines whether a file header has and is large enough to store a FLAC metadata block.
/// The block type is stored in bits 33-39 of the file stream, the first is of type "STREAMINFO".
/// This block type corresponds to a value of 0.
/// More information: https://xiph.org/flac/format.html#metadata_block_streaminfo.
/// </summary>
/// <param name="stream">The flac file stream.</param>
/// <returns>Boolean indicating whether the file has a valid metadata block.</returns>
public static Fin <bool> HasMetadataBlock(Stream stream)
{
long position = stream.Seek(BlockTypeOffset, SeekOrigin.Begin);
Debug.Assert(position == 4, $"Expected stream.Seek position to return 4, instead returned {position}");
Span <byte> buffer = stackalloc byte[1];
var bytesRead = stream.Read(buffer);
if (bytesRead < buffer.Length)
{
return(FileTooShortFlac);
}
return(stream.Length > MetadataBlockSize && BinaryHelpers.Read7BitUnsignedBigEndianIgnoringFirstBit(buffer) == 0);
}