/// <summary>
/// Generic digital data server for a given 32 bit port. The main data buffer that this class updates
/// 'dataBuffer', itself a DigitalEventBuffer object.This method accepts a time range (in seconds referenced to the start of the recording)
/// as input and will copy the portion of the current data buffer that is within that range to the user as a
/// DigitalEventBuffer object. The EstimateAvailableTimeRange method can be used to get an estimate of a valide range
/// to enter for a Read operation. If there is no data in the time range provided, the method returns a null object.
/// </summary>
/// <param name="sampleFrequencyHz"> Sampling frequency of the DAQ that is feeding this server</param>
/// <param name="bufferSizeSec">The requested history of the buffer in seconds</param>
/// <param name="numSamplesPerWrite"> How many samples will the DAQ provide when a Write is called?</param>
public DigitalEventSrv(double sampleFrequencyHz, double bufferSizeSec, int numSamplesPerWrite)
{
this.sampleFrequencyHz = sampleFrequencyHz;
this.dataBuffer = new DigitalEventBuffer(sampleFrequencyHz);
this.numSamplesPerWrite = numSamplesPerWrite;
this.bufferSizeInSamples = (int)Math.Ceiling(bufferSizeSec * sampleFrequencyHz);
}
/// <summary>
/// Write data to the Digital Event Server
/// </summary>
/// <param name="newData"> A digital event buffer containing the digital events to be added to the buffer.</param>
internal void WriteToBuffer(DigitalEventBuffer newData)
{
lock (lockObj)
{
// First we must remove the expired samples (we cannot assume these are
// in temporal order since for 64 channels, we have to write 2x, once for
// each 32 channel recording task)
int i = 0;
while (i < dataBuffer.SampleBuffer.Count)
{
// Remove expired data
if (dataBuffer.SampleBuffer.ElementAt(i) + (ulong)bufferSizeInSamples < currentSample)
{
dataBuffer.SampleBuffer.RemoveAt(i);
dataBuffer.PortStateBuffer.RemoveAt(i);
}
}
// Add new data
dataBuffer.SampleBuffer.AddRange(newData.SampleBuffer);
dataBuffer.PortStateBuffer.AddRange(newData.PortStateBuffer);
// Update the most current sample read
currentSample += (ulong)numSamplesPerWrite;
}
}
/// <summary>
/// Read data from buffer. This method will attempt to retrieve samples within the range
/// specified by the input arguements. The object that is returned
/// will contain information on the true sample bounds. You can use the EstimateAvailableTimeRange
/// method to get a (time-sensitive) estimate for good-arguments for this method.
/// </summary>
/// <param name="desiredStartIndex">earliest sample, referenced to 0, that should be returned</param>
/// <param name="desiredStopIndex">latest sample, referenced to 0, that should be returned</param>
/// <returns>DigitalEventBuffer</returns>
internal DigitalEventBuffer ReadFromBuffer(ulong desiredStartIndex, ulong desiredStopIndex)
{
lock (lockObj)
{
DigitalEventBuffer returnBuffer = new DigitalEventBuffer(dataBuffer.SampleFrequencyHz);
// Collect all the data within the desired sample range and add to the returnBuffer
// object
int i = 0;
while (i < dataBuffer.SampleBuffer.Count)
{
if (dataBuffer.SampleBuffer.ElementAt(i) > desiredStartIndex &&
dataBuffer.SampleBuffer.ElementAt(i) <= desiredStopIndex)
{
returnBuffer.SampleBuffer.Add(dataBuffer.SampleBuffer.ElementAt(i));
returnBuffer.PortStateBuffer.Add(dataBuffer.PortStateBuffer.ElementAt(i));
}
}
// Return the data
return returnBuffer;
}
}