/// <summary>
/// TimeSeriesLibrary is responsible for ensuring that a certain set of meta-parameters (which
/// are saved as database fields) are coordinated with the BLOB of timeseries data. This method
/// records all of the meta-parameters of an irregular timeseries into the fields of this
/// TSParameters object, using the input parameters given to the method.
/// </summary>
public void SetParametersIrregular(
int timeStepCount, DateTime blobStartDate, DateTime blobEndDate, int compressionCode)
{
// Most of the parameters are straightforward
TimeStepUnit = TSDateCalculator.TimeStepUnitCode.Irregular;
TimeStepQuantity = 0;
BlobStartDate = blobStartDate;
CompressionCode = compressionCode;
}
/// <summary>
/// TimeSeriesLibrary is responsible for ensuring that a certain set of meta-parameters (which
/// are saved as database fields) are coordinated with the BLOB of timeseries data. This method
/// records all of the meta-parameters of a regular timeseries into the fields of this TSParameters
/// object, using the input parameters given to the method.
/// </summary>
public void SetParametersRegular(
TSDateCalculator.TimeStepUnitCode timeStepUnit, short timeStepQuantity,
int timeStepCount, DateTime blobStartDate, int compressionCode)
{
// Most of the parameters are straightforward
TimeStepUnit = timeStepUnit;
TimeStepQuantity = timeStepQuantity;
BlobStartDate = blobStartDate;
CompressionCode = compressionCode;
}
/// <summary>
/// This private method creates a List of TimeSeriesValue objects from the given BLOB (byte array)
/// of time series values. The method takes parameters for a maximum number of values,
/// an earliest date, and a latest date, so that only a portion of the BLOB might be
/// converted to the List. This method is designed to do the operations that are common between
/// the public methods ConvertBlobToListLimited() and ConvertBlobToListAll().
/// </summary>
/// <param name="timeStepUnit">TSDateCalculator.TimeStepUnitCode value for Minute,Hour,Day,Week,Month, Year, or Irregular</param>
/// <param name="timeStepQuantity">The number of the given unit that defines the time step.
/// For instance, if the time step is 6 hours long, then this value is 6. If timeStepUnit is
/// Irregular, then this value is ignored.</param>
/// <param name="timeStepCount">the number of time steps that are stored in the blob</param>
/// <param name="blobStartDate">The DateTime value of the first time step in the BLOB. If
/// timeStepUnit is Irregular, then this value is ignored.</param>
/// <param name="applyLimits">If value is true, then nReqValues, reqStartDate, and reqEndDate will be
/// used to limit the portion of the BLOB that is converted to dateValueList. If the value is false, then
/// nReqValues, reqStartDate, and reqEndDate will be ignored.</param>
/// <param name="nReqValues">The maximum number of time steps that should be added to dateValueList.
/// If applyLimits==false, then this value is ignored.</param>
/// <param name="reqStartDate">The earliest date that will be added to dateValueList.
/// If applyLimits==false, then this value is ignored.</param>
/// <param name="reqEndDate">The latest date that will be added to dateValueList.
/// If applyLimits==false, then this value is ignored.</param>
/// <param name="blobData">The BLOB (byte array) that this method will convert into a List</param>
/// <param name="dateValueList">The List of TimeSeriesValues that this method will create from the BLOB.</param>
/// <param name="compressionCode">a generation number that indicates what compression technique to use</param>
/// <returns>The number of time steps added to dateValueList</returns>
private unsafe int ConvertBlobToList(
TSDateCalculator.TimeStepUnitCode timeStepUnit, short timeStepQuantity,
int timeStepCount, DateTime blobStartDate, Boolean applyLimits,
int nReqValues, DateTime reqStartDate, DateTime reqEndDate,
Byte[] blobData, ref List <TimeSeriesValue> dateValueList, int compressionCode)
{
int nValuesRead = 0;
if (timeStepUnit == TSDateCalculator.TimeStepUnitCode.Irregular)
{
// IRREGULAR TIME SERIES
// If we're not limiting the output list (i.e., we're returning every time step from
// the BLOB), then set the size of the intermediate array to match the size of the BLOB.
if (applyLimits == false)
{
nReqValues = timeStepCount;
}
// Allocate an array of date/value pairs that TSBlobCoder method will fill
TSDateValueStruct[] dateValueArray = new TSDateValueStruct[nReqValues];
// Method in the TSBlobCoder class does the real work
nValuesRead = TSBlobCoder.ConvertBlobToArrayIrregular(timeStepCount, applyLimits,
nReqValues, reqStartDate, reqEndDate,
blobData, dateValueArray, compressionCode);
// resize the array so that the List that we make from it will have exactly the right size
if (nValuesRead != nReqValues)
{
Array.Resize <TSDateValueStruct>(ref dateValueArray, nValuesRead);
}
// Convert the array of date/value pairs into the List that will be used by the caller
dateValueList = dateValueArray
.Select(tsv => (TimeSeriesValue)tsv).ToList <TimeSeriesValue>();
}
else
{
// REGULAR TIME SERIES
// If we're not limiting the output list (i.e., we're returning every time step from
// the BLOB), then set the size of the intermediate array to match the size of the BLOB.
if (applyLimits == false)
{
nReqValues = timeStepCount;
}
// Allocate an array of values that TSBlobCoder method will fill
double[] valueArray = new double[nReqValues];
// Method in the TSBlobCoder class does the real work
nValuesRead = TSBlobCoder.ConvertBlobToArrayRegular(timeStepUnit, timeStepQuantity,
timeStepCount, blobStartDate, applyLimits,
nReqValues, reqStartDate, reqEndDate,
blobData, valueArray, compressionCode);
// Allocate an array to hold the time series' date values
DateTime[] dateArray = new DateTime[nValuesRead];
// Fill the array with the date values corresponding to the time steps defined
// for this time series in the database.
TSDateCalculator.FillDateArray(timeStepUnit, timeStepQuantity, nValuesRead, dateArray, reqStartDate);
// Allocate a List of date/value pairs that will be used by the caller
dateValueList = new List <TimeSeriesValue>(nValuesRead);
// Loop through all values, building the List of date/value pairs out of the
// primitive array of dates and primitive array of values.
int i;
for (i = 0; i < nValuesRead; i++)
{
dateValueList.Add(new TimeSeriesValue {
Date = dateArray[i], Value = valueArray[i]
});
}
nValuesRead = i;
}
return(nValuesRead);
}
/// <summary>
/// This method converts a BLOB (byte array) to an array of regular time step timeseries
/// values (double precision floats). The caller must give parameters of the
/// time series, such as time step size and start date. The method will convert
/// only a portion of the BLOB if the applyLimits parameter is true, according to
/// the parameter values nReqValues, reqStartDate, and reqEndDate. If the
/// applyLimits parameter is false, then the method converts the entire BLOB into
/// the given array of values. The array of values must have been allocated
/// large enough prior to calling this method.
/// </summary>
/// <param name="timeStepUnit">TSDateCalculator.TimeStepUnitCode value for Minute,Hour,Day,Week,Month, Year, or Irregular</param>
/// <param name="timeStepQuantity">The number of the given unit that defines the time step.
/// For instance, if the time step is 6 hours long, then this value is 6.</param>
/// <param name="timeStepCount">the number of time steps that are stored in the blob</param>
/// <param name="blobStartDate">Date of the first time step in the BLOB</param>
/// <param name="applyLimits">If true, then the method will convert only a portion of the BLOB,
/// according to the parameter values nReqValues, reqStartDate, and reqEndDate. If false, the method
/// converts the entire BLOB into a value array.</param>
/// <param name="nReqValues">The maximum number of elements that will be converted into the array of values.
/// If applyLimits==false, then this value is ignored.</param>
/// <param name="reqStartDate">The earliest date in the time series that will be written to the array of values.
/// If applyLimits==false, then this value is ignored.</param>
/// <param name="reqEndDate">The latest date in the time series that will be written to the array of values.
/// If applyLimits==false, then this value is ignored.</param>
/// <param name="blobData">the BLOB that will be converted</param>
/// <param name="valueArray">the array of time series values that is produced from the BLOB</param>
/// <param name="compressionCode">a generation number that indicates what compression technique to use</param>
/// <returns>The number of time steps that were actually written to valueArray</returns>
public static unsafe int ConvertBlobToArrayRegular(
TSDateCalculator.TimeStepUnitCode timeStepUnit, short timeStepQuantity,
int timeStepCount, DateTime blobStartDate, bool applyLimits,
int nReqValues, DateTime reqStartDate, DateTime reqEndDate,
Byte[] blobData, double[] valueArray, int compressionCode)
{
// The BLOB is kept in a compressed form, so our first step is to decompress it before
// anything else can be done.
Byte[] decompressedBlobData
= DecompressBlob(blobData, timeStepCount * sizeof(double), compressionCode);
// MemoryStream and BinaryReader objects enable bulk copying of data from the BLOB
using (MemoryStream blobStream = new MemoryStream(decompressedBlobData))
using (BinaryReader blobReader = new BinaryReader(blobStream))
{
// How many elements of size 'double' are in the BLOB?
int numBlobBin = (int)blobStream.Length;
int numBlobValues = numBlobBin / sizeof(double);
int numReadValues = numBlobValues;
int numSkipValues = 0;
int numTruncValues = 0;
// Values might be skipped from the front or truncated from the end of the array,
// but only if this flag is 'true'.
if (applyLimits)
{
// Do we skip any values at the front of the BLOB in order to fullfil the requested start date?
if (reqStartDate > blobStartDate)
{
numSkipValues = TSDateCalculator.CountSteps(blobStartDate, reqStartDate,
timeStepUnit, timeStepQuantity);
}
// compute the last date in the BLOB
DateTime blobEndDate = TSDateCalculator.IncrementDate
(blobStartDate, timeStepUnit, timeStepQuantity, numBlobValues - 1);
// Do we truncate any values at the end of the BLOB in order to fulfill the requested end date?
if (reqEndDate < blobEndDate)
{
numTruncValues = TSDateCalculator.CountSteps(reqEndDate, blobEndDate,
timeStepUnit, timeStepQuantity);
}
// the number of values that can actually be read from the BLOB
numReadValues = Math.Min(numBlobValues - numSkipValues - numTruncValues, nReqValues);
}
// the number of bytes that will actually be read
int numReadBin = numReadValues * sizeof(double);
// the number of bytes that will be skipped
int numSkipBin = numSkipValues * sizeof(double);
// If we've got zero values to read, then we're done early!
if (numReadValues <= 0)
{
return(0);
}
// Transfer the entire array of data as a block
Buffer.BlockCopy(blobReader.ReadBytes(numBlobBin), numSkipBin, valueArray, 0, numReadBin);
return(numReadValues);
}
}
/// <summary>
/// This method copies the parameters of a time series from a TSParameters object
/// into this TSImport object.
/// </summary>
/// <param name="tsp">The TSParameters object that values will be copied from</param>
public void RecordFromTSParameters(TSParameters tsp)
{
TimeStepUnit = tsp.TimeStepUnit;
TimeStepQuantity = tsp.TimeStepQuantity;
BlobStartDate = tsp.BlobStartDate;
CompressionCode = tsp.CompressionCode;
}
// Note--this test class was created primarily b/c we wanted to individually test the different
// compression methods. Hence, we have created the test methods below. The class TSBlobCoder
// certainly deserves full test coverage, but that can be developed later. In the meantime,
// it is generally expected that TSBlobCoder has adequate test coverage via TSLibraryTest.
#region Test Methods for ConvertBlobToListAll() and ConvertListToBlob()
// The series of tests below is for ConvertBlobToListAll and ConvertListToBlob.
// The tests take advantage of the fact that the methods are designed so that
// the series that is put into the BLOB must be identical to the series that
// comes out of the BLOB.
// This method is re-used by the actual test methods that follow.
public void ConvertBlobAll(List <TimeSeriesValue> inList,
TSDateCalculator.TimeStepUnitCode timeStepUnit, short timeStepQuantity,
DateTime blobStartDate, int compressionCode)
{
TSLibrary tsLib = new TSLibrary();
var traceObject = new TSTrace
{
TraceNumber = 1,
TimeStepCount = inList.Count,
EndDate = inList.Last().Date
};
if (timeStepUnit == TSDateCalculator.TimeStepUnitCode.Irregular)
{
var inArray = inList.Select(v => (TSDateValueStruct)v).ToArray();
var outArray = new TSDateValueStruct[inList.Count];
byte[] blobData = TSBlobCoder.ConvertArrayToBlobIrregular(inArray,
compressionCode, traceObject);
int ret = TSBlobCoder.ConvertBlobToArrayIrregular(inList.Count,
false, 0, blobStartDate, blobStartDate,
blobData, outArray, compressionCode);
// The return value of the function must match the number of items in the original list
Assert.AreEqual(ret, inList.Count);
// the count in both lists must match
Assert.AreEqual(inArray.Length, outArray.Length);
// now check each item in the two lists
Boolean AreEqual = true;
for (int i = 0; i < ret; i++)
{
if (outArray[i].Date != inArray[i].Date || outArray[i].Value != inArray[i].Value)
{
AreEqual = false;
}
}
Assert.IsTrue(AreEqual);
}
else
{
var inArray = inList.Select(v => v.Value).ToArray();
var outArray = new Double[inList.Count];
byte[] blobData = TSBlobCoder.ConvertArrayToBlobRegular(inArray,
compressionCode, traceObject);
int ret = TSBlobCoder.ConvertBlobToArrayRegular(timeStepUnit, timeStepQuantity,
inList.Count, blobStartDate,
false, 0, blobStartDate, blobStartDate,
blobData, outArray, compressionCode);
// The return value of the function must match the number of items in the original list
Assert.AreEqual(ret, inList.Count);
// the count in both lists must match
Assert.AreEqual(inArray.Length, outArray.Length);
// now check each item in the two lists
Boolean AreEqual = true;
for (int i = 0; i < ret; i++)
{
if (outArray[i] != inArray[i])
{
AreEqual = false;
}
}
Assert.IsTrue(AreEqual);
}
}