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;
}
}
public MessageAttribute[] ReadAttributes(Stream stream)
{
using (var reader = new BitReader(stream))
{
var attributeCount = reader.Read7BitInt();
if (attributeCount == 0) return Empty;
var attributes = new MessageAttribute[attributeCount];
for (var i = 0; i < attributeCount; i++)
{
var key = reader.ReadString();
var value = reader.ReadString();
attributes[i] = new MessageAttribute(key, value);
}
return attributes;
}
}
public object ReadMessage(Stream stream)
{
using (var bin = new BitReader(stream))
{
var contract = bin.ReadString();
Formatter formatter;
if (!_formattersByContract.TryGetValue(contract, out formatter))
throw new InvalidOperationException(string.Format("Couldn't find contract type for name '{0}'", contract));
var length = bin.Read7BitInt();
var data = bin.ReadBytes(length);
using (var inner = new MemoryStream(data, 0,length))
{
return formatter.DeserializerDelegate(inner);
}
}
}
public IEnumerable<DataRecord> ReadAll(long startOffset, int maxRecordCount)
{
if (startOffset < 0)
throw new ArgumentOutOfRangeException("startOffset");
if (maxRecordCount < 0)
throw new ArgumentOutOfRangeException("maxRecordCount");
var endOffset = GetEndOffset();
if (startOffset >= endOffset)
yield break;
if (!File.Exists(Path.Combine(_path, "stream.dat")))
throw new InvalidOperationException("File stream.chk found but stream.dat file does not exist");
using (_dataStream = new FileStream(Path.Combine(_path, "stream.dat"), FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
using (_dataBits = new BitReader(_dataStream))
{
_dataStream.Seek(startOffset, SeekOrigin.Begin);
int count = 0;
while (_dataStream.Position < endOffset && count <= maxRecordCount)
{
var key = _dataBits.ReadString();
var length = _dataBits.Reader7BitInt();
if (_dataStream.Position + length > _dataStream.Length)
throw new InvalidOperationException("Data length is out of range.");
var data = _dataBits.ReadBytes(length);
yield return new DataRecord(key, data, _dataStream.Position);
if (count == maxRecordCount)
break;
count++;
}
}
}
}
