NDPluginFFT.h

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#ifndef NDPluginFFT_H
#define NDPluginFFT_H

#include <epicsTypes.h>
#include <epicsTime.h>

#include "NDPluginDriver.h"

#define FFTTimeAxisString        "FFT_TIME_AXIS"        /* (asynFloat64Array, r/o) Time axis array */
#define FFTFreqAxisString        "FFT_FREQ_AXIS"        /* (asynFloat64Array, r/o) Frequency axis array */
#define FFTTimePerPointString    "FFT_TIME_PER_POINT"   /* (asynFloat64,      r/o) Time per time point from driver */
#define FFTDirectionString       "FFT_DIRECTION"        /* (asynInt32,        r/w) FFT direction */
#define FFTSuppressDCString      "FFT_SUPPRESS_DC"      /* (asynInt32,        r/w) FFT DC offset suppression */
#define FFTNumAverageString      "FFT_NUM_AVERAGE"      /* (asynInt32,        r/w) # of FFTs to average */
#define FFTNumAveragedString     "FFT_NUM_AVERAGED"     /* (asynInt32,        r/o) # of FFTs averaged */
#define FFTResetAverageString    "FFT_RESET_AVERAGE"    /* (asynInt32,        r/w) Reset FFT average */
#define FFTTimeSeriesString      "FFT_TIME_SERIES"      /* (asynFloat64Array, r/o) Time series data */
#define FFTRealString            "FFT_REAL"             /* (asynFloat64Array, r/o) Real part of FFT */
#define FFTImaginaryString       "FFT_IMAGINARY"        /* (asynFloat64Array, r/o) Imaginary part of FFT */
#define FFTAbsValueString        "FFT_ABS_VALUE"        /* (asynFloat64Array, r/o) Absolute value of FFT */

typedef struct {
  int rank;
  int nTimeXIn;
  int nTimeYIn;
  int nTimeX;
  int nTimeY;
  int nFreqX;
  int nFreqY;
  int suppressDC;
  int numAverage;
  double *timeSeries;
  double *FFTComplex;
  double *FFTReal;
  double *FFTImaginary;
  double *FFTAbsValue;
} fftPvt_t;

class epicsShareClass NDPluginFFT : public NDPluginDriver {
public:
  NDPluginFFT(const char *portName, int queueSize, int blockingCallbacks, 
              const char *NDArrayPort, int NDArrayAddr, 
              int maxBuffers, size_t maxMemory,
              int priority, int stackSize, int maxThreads);

  //These methods override the virtual methods in the base class
  void processCallbacks(NDArray *pArray);

protected:

  int P_FFTTimeAxis;
  #define FIRST_NDPLUGIN_FFT_PARAM P_FFTTimeAxis
  int P_FFTFreqAxis;
  int P_FFTTimePerPoint;
  int P_FFTDirection;
  int P_FFTSuppressDC;
  int P_FFTNumAverage;
  int P_FFTNumAveraged;
  int P_FFTResetAverage;

  int P_FFTTimeSeries;
  int P_FFTReal;
  int P_FFTImaginary;
  int P_FFTAbsValue;
                                
private:
  template <typename epicsType> void convertToDoubleT(NDArray *pArray, fftPvt_t *pPvt);
  void allocateArrays(fftPvt_t *pPvt, bool sizeChanged);
  void createAxisArrays(fftPvt_t *pPvt);
  void computeFFT_1D(fftPvt_t *pPvt);
  void computeFFT_2D(fftPvt_t *pPvt);
  void doArrayCallbacks(fftPvt_t *pPvt);
  int nextPow2(int v);

  int numAverage_;
  int uniqueId_;
  int nTimeXIn_;
  int nTimeYIn_;
  // Note FFTAbsValue_ is guaranteed to be size nFreqX_ * nFreqY_
  // These could change between when a thread began computing the FFT and when it does the callbacks
  int nFreqX_;
  int nFreqY_;
  double *FFTAbsValue_;
  double timePerPoint_; /* Actual time between points in input arrays */
  double *timeAxis_;
  double *freqAxis_;
};
    
#endif //NDPluginFFT_H