public static bool TryReadFrame(Stream source, out StorageFrameDecoded result)
{
result = default(StorageFrameDecoded);
try
{
result = ReadFrame(source);
return !result.IsEmpty;
}
catch (EndOfStreamException)
{
// we are done
return false;
}
catch (Exception ex)
{
Trace.WriteLine(ex);
// Auto-clean?
return false;
}
}
public static StorageFrameDecoded ReadFrame(Stream source)
{
using (var binary = new BitReader(source))
{
var version = binary.ReadInt64();
var name = binary.ReadString();
var len = binary.Read7BitInt();
var bytes = binary.ReadBytes(len);
var sha1Expected = binary.ReadBytes(20);
var decoded = new StorageFrameDecoded(bytes, name, version);
if (decoded.IsEmpty && sha1Expected.All(b => b == 0))
{
// this looks like end of the stream.
return decoded;
}
//SHA1. TODO: compute hash nicely
var sha1Actual = EncodeFrame(name, bytes, version).Hash;
if (!sha1Expected.SequenceEqual(sha1Actual))
throw new StorageFrameException("SHA mismatch in data frame");
return decoded;
}
}