/// <summary>
/// Creates a new <see cref="CommonFrameHeader"/> from given <paramref name="buffer"/>.
/// </summary>
/// <param name="buffer">Buffer that contains data to parse.</param>
/// <param name="startIndex">Start index into buffer where valid data begins.</param>
public CommonFrameHeader(byte[] buffer, int startIndex)
{
// Validate SEL Fast Message data image
if (buffer[startIndex] != Common.HeaderByte1 || buffer[startIndex + 1] != Common.HeaderByte2)
{
throw new InvalidOperationException($"Bad data stream, expected header bytes 0xA546 as first bytes in SEL Fast Message frame, got 0x{buffer[startIndex].ToString("X").PadLeft(2, '0')}{buffer[startIndex + 1].ToString("X").PadLeft(2, '0')}");
}
ushort sampleCount;
uint secondOfCentury;
NtpTimeTag timetag;
// Parse relevant common header values
m_frameSize = (FrameSize)buffer[startIndex + 2];
m_idCode = BigEndian.ToUInt32(buffer, startIndex + 12);
sampleCount = BigEndian.ToUInt16(buffer, startIndex + 18);
secondOfCentury = BigEndian.ToUInt32(buffer, startIndex + 20);
// We use an NTP time tag since SEL Fast Message SOC also starts at 1/1/1900
timetag = new NtpTimeTag(secondOfCentury, 0);
// Data frames have subsecond time information, so we add this fraction of time to current seconds value
timetag = new NtpTimeTag(timetag.Value + sampleCount * 50.0M / 1000.0M);
// Cache timestamp value
m_timestamp = timetag.ToDateTime().Ticks;
}
/// <summary>
/// Creates a new <see cref="CommonFrameHeader"/> from given <paramref name="buffer"/>.
/// </summary>
/// <param name="buffer">Buffer that contains data to parse.</param>
/// <param name="startIndex">Start index into buffer where valid data begins.</param>
public CommonFrameHeader(byte[] buffer, int startIndex)
{
uint secondOfCentury = BigEndian.ToUInt32(buffer, startIndex);
m_sampleCount = BigEndian.ToUInt16(buffer, startIndex + 4);
// We go ahead and pre-grab cell's status flags so we can determine framelength - we
// leave startindex at 6 so that cell will be able to parse flags as needed - note
// this increases needed common frame header size by 2 (i.e., BinaryLength + 2)
m_statusFlags = BigEndian.ToUInt16(buffer, startIndex + FixedLength);
// NTP timestamps based on NtpTimeTag class are designed to work for dates between
// 1968-01-20 and 2104-02-26 based on recommended bit interpretation in RFC-2030.
NtpTimeTag timetag = new NtpTimeTag(secondOfCentury, 0);
// Cache timestamp value
m_timestamp = timetag.ToDateTime().Ticks;
}
/// <summary>
/// Creates a new <see cref="CommonFrameHeader"/> from given <paramref name="buffer"/>.
/// </summary>
/// <param name="configurationFrame">IEEE 1344 <see cref="ConfigurationFrame"/> if already parsed.</param>
/// <param name="buffer">Buffer that contains data to parse.</param>
/// <param name="startIndex">Start index into buffer where valid data begins.</param>
public CommonFrameHeader(ConfigurationFrame configurationFrame, byte[] buffer, int startIndex)
{
uint secondOfCentury = BigEndian.ToUInt32(buffer, startIndex);
m_sampleCount = BigEndian.ToUInt16(buffer, startIndex + 4);
// We go ahead and pre-grab cell's status flags so we can determine framelength - we
// leave startindex at 6 so that cell will be able to parse flags as needed - note
// this increases needed common frame header size by 2 (i.e., BinaryLength + 2)
m_statusFlags = BigEndian.ToUInt16(buffer, startIndex + FixedLength);
// NTP timestamps based on NtpTimeTag class are designed to work for dates between
// 1968-01-20 and 2104-02-26 based on recommended bit interpretation in RFC-2030.
NtpTimeTag timetag = new NtpTimeTag(secondOfCentury, 0);
// Data frames have subsecond time information, so we add this fraction of time to current seconds value
if (TypeID == IEEE1344.FrameType.DataFrame && configurationFrame != null)
{
timetag.Value += SampleCount / Math.Truncate((double)Common.MaximumSampleCount / (double)configurationFrame.Period) / (double)configurationFrame.FrameRate;
}
// Cache timestamp value
m_timestamp = timetag.ToDateTime().Ticks;
}
/// <summary>
/// Creates a new <see cref="CommonFrameHeader"/> from given <paramref name="buffer"/>.
/// </summary>
/// <param name="parseWordCountFromByte">Defines flag that interprets word count in packet header from a byte instead of a word.</param>
/// <param name="usePhasorDataFileFormat">Defines flag that determines if source data is in the Phasor Data File Format (i.e., a DST file).</param>
/// <param name="configFrame">Previously parsed configuration frame, if available.</param>
/// <param name="buffer">Buffer that contains data to parse.</param>
/// <param name="startIndex">Start index into buffer where valid data begins.</param>
/// <param name="length">Maximum length of valid data from start index.</param>
public CommonFrameHeader(bool parseWordCountFromByte, bool usePhasorDataFileFormat, ConfigurationFrame configFrame, byte[] buffer, int startIndex, int length)
{
uint secondOfCentury;
// Determines if format is for DST file or streaming data
m_usePhasorDataFileFormat = usePhasorDataFileFormat;
if (m_usePhasorDataFileFormat)
{
// Handle phasor file format data protocol steps
if (buffer[startIndex] == PhasorProtocols.Common.SyncByte && buffer[startIndex + 1] == Common.PhasorFileFormatFlag)
{
// Bail out and leave frame length zero if there's not enough buffer to parse complete fixed portion of header
if (length >= DstHeaderFixedLength)
{
// Read full DST header
m_packetNumber = (byte)BPAPDCstream.FrameType.ConfigurationFrame;
m_fileType = (FileType)buffer[startIndex + 2];
m_fileVersion = (FileVersion)buffer[startIndex + 3];
m_sourceID = Encoding.ASCII.GetString(buffer, startIndex + 4, 4);
uint headerLength = BigEndian.ToUInt32(buffer, startIndex + 8);
secondOfCentury = BigEndian.ToUInt32(buffer, startIndex + 12);
switch (m_fileType)
{
case FileType.PdcNtp:
RoughTimestamp = new NtpTimeTag(secondOfCentury, 0).ToDateTime().Ticks;
break;
case FileType.PdcUnix:
RoughTimestamp = new UnixTimeTag(secondOfCentury).ToDateTime().Ticks;
break;
default:
RoughTimestamp = 0;
break;
}
m_startSample = BigEndian.ToUInt32(buffer, startIndex + 16);
m_sampleInterval = BigEndian.ToUInt16(buffer, startIndex + 20);
m_sampleRate = BigEndian.ToUInt16(buffer, startIndex + 22);
m_rowLength = BigEndian.ToUInt32(buffer, startIndex + 24);
m_totalRows = BigEndian.ToUInt32(buffer, startIndex + 28);
secondOfCentury = BigEndian.ToUInt32(buffer, startIndex + 32);
switch (m_fileType)
{
case FileType.PdcNtp:
m_triggerTime = new NtpTimeTag(secondOfCentury, 0).ToDateTime().Ticks;
break;
case FileType.PdcUnix:
m_triggerTime = new UnixTimeTag(secondOfCentury).ToDateTime().Ticks;
break;
default:
m_triggerTime = 0;
break;
}
m_triggerSample = BigEndian.ToUInt32(buffer, startIndex + 36);
m_preTriggerRows = BigEndian.ToUInt32(buffer, startIndex + 40);
m_triggerPMU = BigEndian.ToUInt16(buffer, startIndex + 44);
m_triggerType = BigEndian.ToUInt16(buffer, startIndex + 46);
m_userInformation = Encoding.ASCII.GetString(buffer, startIndex + 48, 80).Trim();
m_pmuCount = BigEndian.ToUInt32(buffer, startIndex + 128);
FrameLength = unchecked ((ushort)headerLength);
}
}
else
{
// Must assume this is a data row if there are no sync bytes
m_packetNumber = (byte)BPAPDCstream.FrameType.DataFrame;
m_rowFlags = BigEndian.ToUInt32(buffer, startIndex);
if (configFrame is null)
{
FrameLength = FixedLength;
}
else
{
uint sampleIndex = configFrame.SampleIndex;
CommonFrameHeader configFrameHeader = configFrame.CommonHeader;
if (configFrameHeader is null)
{
FrameLength = FixedLength;
}
else
{
// Assign row length to make sure parser knows how much data it needs
FrameLength = unchecked ((ushort)configFrameHeader.RowLength);
// Calculate timestamp as offset plus sample index * frame rate
RoughTimestamp = configFrameHeader.RoughTimestamp + Ticks.FromSeconds(sampleIndex * (1.0D / configFrameHeader.FrameRate));
}
// Increment sample index for next row
configFrame.SampleIndex = sampleIndex + 1;
}
}
}
else
{
// Handle streaming data protocol steps
if (buffer[startIndex] != PhasorProtocols.Common.SyncByte)
{
throw new InvalidOperationException($"Bad data stream, expected sync byte 0xAA as first byte in BPA PDCstream frame, got 0x{buffer[startIndex].ToString("X").PadLeft(2, '0')}");
}
// Get packet number
m_packetNumber = buffer[startIndex + 1];
// Some older streams have a bad word count (e.g., some data streams have a 0x01 as the third byte
// in the stream - this should be a 0x00 to make the word count come out correctly). The following
// compensates for this erratic behavior
m_wordCount = parseWordCountFromByte ? buffer[startIndex + 3] : BigEndian.ToUInt16(buffer, startIndex + 2);
// If this is a data frame get a rough timestamp down to the second (full parse will get accurate timestamp), this way
// data frames that don't get fully parsed because configuration hasn't been received will still show a timestamp
if (m_packetNumber > 0 && length > 8)
{
secondOfCentury = BigEndian.ToUInt32(buffer, startIndex + 4);
// Until configuration is available, we make a guess at time tag type - this will just be
// used for display purposes until a configuration frame arrives. If second of century
// is greater than 3155673600 (SOC value for NTP timestamp 1/1/2007), then this is likely
// an NTP time stamp (else this is a Unix time tag for the year 2069 - not likely).
RoughTimestamp = secondOfCentury > 3155673600 ?
new NtpTimeTag(secondOfCentury, 0).ToDateTime().Ticks :
new UnixTimeTag(secondOfCentury).ToDateTime().Ticks;
}
}
}
