/// <summary>
/// Reads the data for an item at the specified times.
/// </summary>
private StatusCode ReadAtTime(HdaHistoryReadAtTimeRequest request)
{
string methodName = "IOPCHDA_SyncRead.ReadAtTime";
IntPtr ppItemValues;
IntPtr ppErrors;
System.Runtime.InteropServices.ComTypes.FILETIME[] pTimestamps = new System.Runtime.InteropServices.ComTypes.FILETIME[request.ReqTimes.Count];
for (int ii = 0; ii < pTimestamps.Length; ii++)
{
pTimestamps[ii] = ComUtils.GetFILETIME(request.ReqTimes[ii]);
}
try
{
IOPCHDA_SyncRead server = BeginComCall<IOPCHDA_SyncRead>(methodName, true);
server.ReadAtTime(
pTimestamps.Length,
pTimestamps,
1,
new int[] { request.ServerHandle },
out ppItemValues,
out ppErrors);
}
catch (Exception e)
{
ComCallError(methodName, e);
return StatusCodes.BadUnexpectedError;
}
finally
{
EndComCall(methodName);
}
// check for error.
int[] errors = ComUtils.GetInt32s(ref ppErrors, 1, true);
if (errors[0] < 0)
{
return StatusCodes.BadNodeIdUnknown;
}
// check if operation halted.
request.Completed = true;
// unmarshal the results.
OPCHDA_ITEM result = (OPCHDA_ITEM)Marshal.PtrToStructure(ppItemValues, typeof(OPCHDA_ITEM));
if (result.dwCount > 0)
{
object[] values = ComUtils.GetVARIANTs(ref result.pvDataValues, result.dwCount, true);
int[] qualities = ComUtils.GetInt32s(ref result.pdwQualities, result.dwCount, true);
DateTime[] timestamps = ComUtils.GetDateTimes(ref result.pftTimeStamps, result.dwCount, true);
request.Results = new DataValueCollection(result.dwCount);
for (int ii = 0; ii < result.dwCount; ii++)
{
DataValue value = new DataValue();
value.Value = ComUtils.ProcessComValue(values[ii]);
value.StatusCode = ComUtils.GetHdaQualityCode(Utils.ToUInt32(qualities[ii]));
value.SourceTimestamp = timestamps[ii];
request.Results.Add(value);
}
}
Marshal.FreeCoTaskMem(ppItemValues);
if (result.dwCount == 0)
{
return StatusCodes.GoodNoData;
}
return StatusCodes.Good;
}
/// <summary>
/// Reads the data history at specified times.
/// </summary>
public StatusCode ReadHistory(HdaHistoryReadAtTimeRequest request)
{
if (request == null)
{
return StatusCodes.BadNothingToDo;
}
HdaItem[] items = GetItems(request.ItemId);
if (items == null || items[0].Error < 0)
{
return StatusCodes.BadNodeIdUnknown;
}
request.ServerHandle = items[0].ServerHandle;
try
{
return ReadAtTime(request);
}
catch (Exception)
{
return StatusCodes.BadUnexpectedError;
}
finally
{
ReleaseItemHandles(request.ServerHandle);
request.ServerHandle = 0;
}
}
/// <summary>
/// Reads the history of an HDA item.
/// </summary>
private ServiceResult HistoryReadAtTime(
ServerSystemContext context,
ComHdaClient client,
ReadAtTimeDetails details,
TimestampsToReturn timestampsToReturn,
HistoryReadValueId nodeToRead,
HdaParsedNodeId parsedNodeId,
HistoryReadResult result)
{
// create the request or load it from a continuation point.
HdaHistoryReadAtTimeRequest request = null;
if (nodeToRead.ContinuationPoint == null)
{
request = new HdaHistoryReadAtTimeRequest(parsedNodeId.RootId, details, nodeToRead);
}
else
{
request = LoadContinuationPoint(context, nodeToRead.ContinuationPoint) as HdaHistoryReadAtTimeRequest;
if (request == null)
{
return StatusCodes.BadContinuationPointInvalid;
}
}
// fetch the data.
result.StatusCode = client.ReadHistory(request);
// fill in the results.
if (request.Results != null)
{
HistoryData data = new HistoryData();
data.DataValues = request.Results;
result.HistoryData = new ExtensionObject(data);
}
// create a new continuation point.
if (!request.Completed)
{
result.ContinuationPoint = SaveContinuationPoint(context, request);
}
return result.StatusCode;
}
