private void DownstreamThreadProc()
{
while (!_disposed)
{
// Fetch a Telegram and Signal any waiting threads
// (Note: this will always be a Scan-Data telegram because the thread will be suspended for all other communications.)
_lastTelegram = _client.ReceiveTelegram();
_downstreamTurnstile.Set();
}
}
protected override void UpdateImpl()
{
if ((null == _client) || (!_client.IsConnected) || (null == _downstreamTurnstile))
{
throw new InvalidOperationException($"{Name} disconnected");
}
try
{
// Wait for the next Scan-Data Telegram
_downstreamTurnstile.WaitOne();
CoLaBTelegram scanDataTelegram = _lastTelegram;
NetworkBinaryReader scanData = new NetworkBinaryReader(scanDataTelegram);
// Miscellaneous Metadata
UInt16 versionNumber = scanData.ReadUInt16();
if (1 != versionNumber)
{
log.Warn($"{Name}: unexpected version number in telegram: {versionNumber}");
}
scanData.Skip(2);
UInt32 serialNumber = scanData.ReadUInt32();
if (_serialNumber != serialNumber)
{
_serialNumber = serialNumber;
base.serialNumber = serialNumber.ToString();
}
scanData.Skip(1);
byte deviceStatus = scanData.ReadByte();
if (0 != deviceStatus)
{
log.Error($"{Name}: unexpected device status: {deviceStatus}");
}
scanData.Skip(2);
_scanCounter = scanData.ReadUInt16();
scanData.Skip(4);
_timeStamp = scanData.ReadUInt32();
// Skip: input states, output states, reserved bytes, frequency information, encoders
scanData.Skip(2 + 2 + 2 + 4 + 4 + 2);
// 16-bit Channels
UInt16 channelCount16 = scanData.ReadUInt16();
if (1 != channelCount16)
{
log.Error($"{Name}: unexpected number of 16-bit channels: {channelCount16}");
}
_channelName = scanData.ReadString(5);
_scalingFactor = scanData.ReadSingle() * 0.001f;
float scalingOffset = scanData.ReadSingle();
int startingAngle = scanData.ReadInt32();
int angularStepWidth = (int)scanData.ReadUInt16();
if ((_startingAngle != startingAngle) || (_angularStepWidth != angularStepWidth))
{
_startingAngle = startingAngle;
_angularStepWidth = angularStepWidth;
_directions = null;
}
int dataCount = (int)scanData.ReadUInt16();
// Initialize or Reinitialize array of Polar Radii
if (null == _radii)
{
_radii = new UInt16[dataCount];
_directions = null;
}
else if (_radii.Length != dataCount)
{
Array.Resize(ref _radii, dataCount);
_directions = null;
}
// Read 16-bit unsigned pixels (reversed)
for (int i = (dataCount - 1); i >= 0; --i)
{
_radii[i] = scanData.ReadUInt16();
}
}
catch (MetriCam2Exception)
{
// Pass MetriCam API Exceptions without alteration
throw;
}
catch (Exception foreignException)
{
// Wrap and Throw other exceptions encountered during Connection
throw ExceptionBuilder.Build(typeof(ImageAcquisitionFailedException), Name, foreignException.Message, foreignException);
}
}
protected override void ConnectImpl()
{
try
{
// Reinitialize a Disconnected Client
if ((null != _client) && (!_client.IsConnected))
{
_client.Dispose();
_client = null;
}
// Connect when necessary
if (null == _client)
{
_client = CoLaBClient.Connect(_remoteEndPoint);
log.Debug($"{Name}: connected to {_remoteEndPoint}");
try
{
// Request Scan-Data Telegrams
CoLaBTelegram acknowledgement = _client.SendTelegram(CoLaCommandType.Event, "LMDscandata", (telegramWriter) =>
{
telegramWriter.Write(0x01);
}, acknowledgeTimeout: _timeoutMilliseconds);
if (acknowledgement.Data[acknowledgement.Offset] != 0)
{
log.Debug($"{Name}: CoLa (binary) telegram subscription established");
}
else
{
throw ExceptionBuilder.Build(typeof(ConnectionFailedException), Name, "error_connectionFailed", "CoLa (binary) telegram subscription failed");
}
}
catch
{
// Dispose the TCP/IP Client immediately
try
{
_client.Dispose();
_client = null;
}
catch
{
// Suppress secondary exceptions
}
// Rethrow the original exception
throw;
}
// Begin receiving telegrams in a background thread
_downstreamThread = new Thread(DownstreamThreadProc);
_downstreamThread.Name = Name;
_downstreamThread.IsBackground = true;
_downstreamThread.Start();
}
}
catch (MetriCam2Exception)
{
// Pass MetriCam API Exceptions without alteration
throw;
}
catch (Exception foreignException)
{
// Wrap and Throw other exceptions encountered during Connection
throw ExceptionBuilder.Build(typeof(ConnectionFailedException), Name, foreignException.Message, foreignException);
}
}