/// <summary>
/// Writes the <paramref name="dataPoint"/> to the <see cref="ArchiveDataBlock"/>.
/// </summary>
/// <param name="dataPoint"><see cref="IDataPoint"/> to write.</param>
/// <param name="exception">Any <see cref="Exception"/> that may have been encountered while writing.</param>
/// <returns>
/// <c>true</c> if data point was written; otherwise, <c>false</c>.
/// </returns>
public bool Write(IDataPoint dataPoint, out Exception exception)
{
exception = null;
try
{
TimeTag value = dataPoint.Time;
// Do not attempt to write values with a bad timestamp, this will just throw an exception
if (value.CompareTo(TimeTag.MinValue) < 0 || value.CompareTo(TimeTag.MaxValue) > 0)
{
exception = new TimeTagException("Skipping data write for point: Bad time tag, value must between 01/01/1995 and 01/19/2063");
}
else
{
if (SlotsAvailable > 0)
{
// We have enough space to write the provided point data to the data block.
m_lastActivityTime = DateTime.UtcNow;
lock (m_parent.FileData)
{
// Write the data.
if (m_writeCursor != m_parent.FileData.Position)
{
m_parent.FileData.Seek(m_writeCursor, SeekOrigin.Begin);
}
dataPoint.CopyBinaryImageToStream(m_parent.FileData);
// Update the write cursor.
m_writeCursor = m_parent.FileData.Position;
// Flush the data if configured.
if (!m_parent.CacheWrites)
{
m_parent.FileData.Flush();
}
}
}
else
{
exception = new InvalidOperationException("Skipping data write for point: No slots available for writing new data");
}
}
}
catch (Exception ex)
{
exception = new InvalidOperationException($"Skipping data write for point: {ex.Message}", ex);
}
if ((object)exception == null)
{
return(true);
}
OnDataWriteException(exception);
return(false);
}
/// <summary>
/// Initializes <see cref="ArchiveDataPoint"/> from the specified <paramref name="buffer"/>.
/// </summary>
/// <param name="buffer">Binary image to be used for initializing <see cref="ArchiveDataPoint"/>.</param>
/// <param name="startIndex">0-based starting index of initialization data in the <paramref name="buffer"/>.</param>
/// <param name="length">Valid number of bytes in <paramref name="buffer"/> from <paramref name="startIndex"/>.</param>
/// <returns>Number of bytes used from the <paramref name="buffer"/> for initializing <see cref="ArchiveDataPoint"/>.</returns>
public virtual int ParseBinaryImage(byte[] buffer, int startIndex, int length)
{
if (length >= FixedLength)
{
// Binary image has sufficient data.
Flags = LittleEndian.ToInt16(buffer, startIndex + 4);
Value = LittleEndian.ToSingle(buffer, startIndex + 6);
TimeTag value = new TimeTag(LittleEndian.ToInt32(buffer, startIndex) + // Seconds
((decimal)(m_flags.GetMaskedValue(MillisecondMask) >> 5) / 1000)); // Milliseconds
// Make sure to properly validate timestamps for newly initialized or possibly corrupted blocks
if (value.CompareTo(TimeTag.MinValue) < 0 || value.CompareTo(TimeTag.MaxValue) > 0)
{
value = TimeTag.MinValue;
}
Time = value;
return(FixedLength);
}
// Binary image does not have sufficient data.
return(0);
}
/// <summary>
/// Tests if the <paramref name="dataBlockPointer"/> matches the specified search criteria.
/// </summary>
/// <param name="dataBlockPointer"><see cref="ArchiveDataBlockPointer"/> to test.</param>
/// <param name="historianID">Desired historian ID.</param>
/// <param name="startTime">Desired start time.</param>
/// <param name="endTime">Desired end time.</param>
/// <returns><c>true</c> if the specified <paramref name="dataBlockPointer"/> is for <paramref name="historianID"/> and falls within the <paramref name="startTime"/> and <paramref name="endTime"/>; otherwise <c>false</c>.</returns>
public static bool Matches(this ArchiveDataBlockPointer dataBlockPointer, int historianID, TimeTag startTime, TimeTag endTime)
{
// Note: The StartTime value of the pointer is ignored if m_searchStartTime = TimeTag.MinValue and
// m_searchEndTime = TimeTag.MaxValue. In this case only the PointID value is compared. This
// comes in handy when the first or last pointer is to be found from the list of pointers for
// a point ID in addition to all the pointers for a point ID.
if ((object)dataBlockPointer != null)
{
return(dataBlockPointer.HistorianID == historianID &&
(startTime.CompareTo(TimeTag.MinValue) == 0 || dataBlockPointer.StartTime.CompareTo(startTime) >= 0) &&
(endTime.CompareTo(TimeTag.MaxValue) == 0 || dataBlockPointer.StartTime.CompareTo(endTime) <= 0));
}
return(false);
}
/// <summary>
/// Compares the current <see cref="ArchiveDataBlockPointer"/> object to <paramref name="obj"/>.
/// </summary>
/// <param name="obj">Object against which the current <see cref="ArchiveDataBlockPointer"/> object is to be compared.</param>
/// <returns>
/// Negative value if the current <see cref="ArchiveDataBlockPointer"/> object is less than <paramref name="obj"/>,
/// Zero if the current <see cref="ArchiveDataBlockPointer"/> object is equal to <paramref name="obj"/>,
/// Positive value if the current <see cref="ArchiveDataBlockPointer"/> object is greater than <paramref name="obj"/>.
/// </returns>
public virtual int CompareTo(object obj)
{
ArchiveDataBlockPointer other = obj as ArchiveDataBlockPointer;
if ((object)other == null)
{
return(1);
}
int result = m_historianID.CompareTo(other.HistorianID);
if (result != 0)
{
return(result);
}
return(m_startTime.CompareTo(other.StartTime));
}
/// <summary>
/// Compares the current <see cref="ArchiveDataPoint"/> object to <paramref name="obj"/>.
/// </summary>
/// <param name="obj">Object against which the current <see cref="ArchiveDataPoint"/> object is to be compared.</param>
/// <returns>
/// Negative value if the current <see cref="ArchiveDataPoint"/> object is less than <paramref name="obj"/>,
/// Zero if the current <see cref="ArchiveDataPoint"/> object is equal to <paramref name="obj"/>,
/// Positive value if the current <see cref="ArchiveDataPoint"/> object is greater than <paramref name="obj"/>.
/// </returns>
public virtual int CompareTo(object obj)
{
ArchiveDataPoint other = obj as ArchiveDataPoint;
if (other == null)
{
return(1);
}
else
{
int result = m_historianID.CompareTo(other.HistorianID);
if (result != 0)
{
return(result);
}
else
{
return(m_time.CompareTo(other.Time));
}
}
}
/// <summary>
/// Initializes <see cref="ArchiveDataPoint"/> from the specified <paramref name="buffer"/>.
/// </summary>
/// <param name="buffer">Binary image to be used for initializing <see cref="ArchiveDataPoint"/>.</param>
/// <param name="startIndex">0-based starting index of initialization data in the <paramref name="buffer"/>.</param>
/// <param name="length">Valid number of bytes in <paramref name="buffer"/> from <paramref name="startIndex"/>.</param>
/// <returns>Number of bytes used from the <paramref name="buffer"/> for initializing <see cref="ArchiveDataPoint"/>.</returns>
public virtual int ParseBinaryImage(byte[] buffer, int startIndex, int length)
{
if (length >= FixedLength)
{
// Binary image has sufficient data.
Flags = LittleEndian.ToInt16(buffer, startIndex + 4);
Value = LittleEndian.ToSingle(buffer, startIndex + 6);
TimeTag value = new TimeTag(LittleEndian.ToInt32(buffer, startIndex) + // Seconds
((decimal)(m_flags.GetMaskedValue(MillisecondMask) >> 5) / 1000)); // Milliseconds
// Make sure to properly validate timestamps for newly initialized or possibly corrupted blocks
if (value.CompareTo(TimeTag.MinValue) < 0 || value.CompareTo(TimeTag.MaxValue) > 0)
value = TimeTag.MinValue;
Time = value;
return FixedLength;
}
// Binary image does not have sufficient data.
return 0;
}
private bool FindHistoricArchiveFileForWrite(Info fileInfo, TimeTag searchTime)
{
return ((object)fileInfo != null &&
searchTime.CompareTo(fileInfo.StartTimeTag) >= 0 &&
searchTime.CompareTo(fileInfo.EndTimeTag) <= 0);
}
private bool FindHistoricArchiveFileForRead(Info fileInfo, TimeTag startTime, TimeTag endTime)
{
return ((object)fileInfo != null &&
((startTime.CompareTo(fileInfo.StartTimeTag) >= 0 && startTime.CompareTo(fileInfo.EndTimeTag) <= 0) ||
(endTime.CompareTo(fileInfo.StartTimeTag) >= 0 && endTime.CompareTo(fileInfo.EndTimeTag) <= 0) ||
(startTime.CompareTo(fileInfo.StartTimeTag) < 0 && endTime.CompareTo(fileInfo.EndTimeTag) > 0)));
}
// Read data implementation
private IEnumerable<IDataPoint> ReadData(IEnumerable<int> historianIDs, TimeTag startTime, TimeTag endTime, IDataPoint resumeFrom, bool timeSorted)
{
// Yield to archive rollover process.
m_rolloverWaitHandle.WaitOne();
// Ensure that the current file is open.
if (!IsOpen)
throw new InvalidOperationException(string.Format("\"{0}\" file is not open", m_fileName));
// Ensure that the current file is active.
if (m_fileType != ArchiveFileType.Active)
throw new InvalidOperationException("Data can only be directly read from files that are Active");
// Ensure that the start and end time are valid.
if (startTime.CompareTo(endTime) > 0)
throw new ArgumentException("End Time precedes Start Time in the specified time span");
List<Info> dataFiles = new List<Info>();
bool pendingRollover = false;
bool usingActiveFile = false;
if (startTime.CompareTo(m_fat.FileStartTime) < 0)
{
// Data is to be read from historic file(s) - make sure that the list has been built
if (m_buildHistoricFileListThread.IsAlive)
m_buildHistoricFileListThread.Join();
lock (m_historicArchiveFiles)
{
dataFiles.AddRange(m_historicArchiveFiles.FindAll(info => FindHistoricArchiveFileForRead(info, startTime, endTime)));
}
}
if (endTime.CompareTo(m_fat.FileStartTime) >= 0)
{
// Data is to be read from the active file.
Info activeFileInfo = new Info(m_fileName)
{
StartTimeTag = m_fat.FileStartTime,
EndTimeTag = m_fat.FileEndTime
};
dataFiles.Add(activeFileInfo);
}
// Read data from all qualifying files.
foreach (Info dataFile in dataFiles)
{
ArchiveFile file = null;
try
{
if (string.Compare(dataFile.FileName, m_fileName, StringComparison.OrdinalIgnoreCase) == 0)
{
// Read data from current file.
usingActiveFile = true;
file = this;
// Atomically increment total number of readers for active file
Interlocked.Increment(ref m_activeFileReaders);
// Handle race conditions between rollover
// and incrementing the active readers
while (m_rolloverInProgress)
{
Interlocked.Decrement(ref m_activeFileReaders);
m_rolloverWaitHandle.WaitOne();
Interlocked.Increment(ref m_activeFileReaders);
}
}
else
{
// Read data from historic file.
usingActiveFile = false;
file = new ArchiveFile();
file.FileName = dataFile.FileName;
file.StateFile = m_stateFile;
file.IntercomFile = m_intercomFile;
file.MetadataFile = m_metadataFile;
file.FileAccessMode = FileAccess.Read;
file.Open();
}
// Create new data point scanner for the desired points in this file and given time range
IArchiveFileScanner scanner;
if (timeSorted)
scanner = new TimeSortedArchiveFileScanner();
else
scanner = new ArchiveFileScanner();
scanner.FileAllocationTable = file.Fat;
scanner.HistorianIDs = historianIDs;
scanner.StartTime = startTime;
scanner.EndTime = endTime;
scanner.ResumeFrom = resumeFrom;
scanner.DataReadExceptionHandler = (sender, e) => OnDataReadException(e.Argument);
// Reset resumeFrom to scan from beginning after picking up where left off from roll over
resumeFrom = null;
// Return data points
foreach (IDataPoint dataPoint in scanner.Read())
{
yield return dataPoint;
// If a rollover needs to happen, we need to relinquish read lock and close file
if (m_rolloverInProgress)
{
resumeFrom = dataPoint;
pendingRollover = true;
break;
}
}
}
finally
{
if (usingActiveFile)
{
// Atomically decrement active file reader count to signal in-process code that read is complete or yielded
Interlocked.Decrement(ref m_activeFileReaders);
}
else if ((object)file != null)
{
file.Dispose();
}
}
if (pendingRollover)
break;
}
if (pendingRollover)
{
// Recurse into this function with an updated start time and last read point ID so that read can
// resume right where it left off - recursed function call will wait until rollover is complete
foreach (IDataPoint dataPoint in ReadData(historianIDs, startTime, endTime, resumeFrom, timeSorted))
{
yield return dataPoint;
}
}
}
/// <summary>
/// Tests if the <paramref name="dataBlockPointer"/> matches the specified search criteria.
/// </summary>
/// <param name="dataBlockPointer"><see cref="ArchiveDataBlockPointer"/> to test.</param>
/// <param name="historianID">Desired historian ID.</param>
/// <param name="startTime">Desired start time.</param>
/// <param name="endTime">Desired end time.</param>
/// <returns><c>true</c> if the specified <paramref name="dataBlockPointer"/> is for <paramref name="historianID"/> and falls within the <paramref name="startTime"/> and <paramref name="endTime"/>; otherwise <c>false</c>.</returns>
public static bool Matches(this ArchiveDataBlockPointer dataBlockPointer, int historianID, TimeTag startTime, TimeTag endTime)
{
// Note: The StartTime value of the pointer is ignored if m_searchStartTime = TimeTag.MinValue and
// m_searchEndTime = TimeTag.MaxValue. In this case only the PointID value is compared. This
// comes in handy when the first or last pointer is to be found from the list of pointers for
// a point ID in addition to all the pointers for a point ID.
if ((object)dataBlockPointer != null)
return dataBlockPointer.HistorianID == historianID &&
(startTime.CompareTo(TimeTag.MinValue) == 0 || dataBlockPointer.StartTime.CompareTo(startTime) >= 0) &&
(endTime.CompareTo(TimeTag.MaxValue) == 0 || dataBlockPointer.StartTime.CompareTo(endTime) <= 0);
return false;
}
