public static string GetHash(string opt, Stream stream, Func<int, bool> func)
{
FileCheck check;
switch (opt.ToLower()) {
case "crc32":
check = new Crc32();
break;
case "md5":
check = new FileMD5();
break;
default:
check = new FileSha1();
break;
}
check.TransformBlock(stream, func);
return check.Value;
}