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;
}
}
private long GetEndOffset()
{
if (!File.Exists(Path.Combine(_path, "stream.chk")))
return 0;
using (_checkStream = new FileStream(Path.Combine(_path, "stream.chk"), FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
using (_checkBits = new BitReader(_checkStream))
{
// calculate start and end offset
//_checkStream.Seek(0, SeekOrigin.Begin);
return _checkBits.ReadInt64();
}
}
}