Detecting Encoding in C#

public static Encoding GetFileEncoding(string path)
{
	if (path == null)
		throw new ArgumentNullException("path");

	var encodings = Encoding.GetEncodings()
		.Select(e => e.GetEncoding())
		.Select(e => new { Encoding = e, Preamble = e.GetPreamble() })
		.Where(e => e.Preamble.Any())
		.ToArray();

	var maxPrembleLength = encodings.Max(e => e.Preamble.Length);
	byte[] buffer = new byte[maxPrembleLength];

	using (var stream = File.OpenRead(path))
	{
		stream.Read(buffer, 0, (int)Math.Min(maxPrembleLength, stream.Length));
	}

	return encodings
		.Where(enc => enc.Preamble.SequenceEqual(buffer.Take(enc.Preamble.Length)))
		.Select(enc => enc.Encoding)
		.FirstOrDefault() ?? Encoding.Default;
}