lasp/src/lasp/pybind11/lasp_pyindatahandler.cpp

#include <carma>
#include <armadillo>
#define DEBUGTRACE_ENABLED
#include "debugtrace.hpp"
#include "lasp_ppm.h"
#include "lasp_rtaps.h"
#include "lasp_streammgr.h"
#include "lasp_threadedindatahandler.h"
#include <atomic>
#include <chrono>
#include <pybind11/pybind11.h>

using namespace std::literals::chrono_literals;
using std::cerr;
using std::endl;

namespace py = pybind11;

/**
 * @brief Generate a Numpy array from daqdata, does *NOT* create a copy of the
 * data!. Instead, it shares the data from the DaqData container.
 *
 * @tparam T The type of the stored sample
 * @param d The daqdata to convert
 *
 * @return Numpy array
 */
template <typename T,bool copy=false> py::array_t<T> getPyArrayNoCpy(const DaqData &d) {
  // https://github.com/pybind/pybind11/issues/323
  //
  // When a valid object is passed as 'base', it tells pybind not to take
  // ownership of the data, because 'base' will own it. In fact 'packet' will
  // own it, but - psss! - , we don't tell it to pybind... Alos note that ANY
  // valid object is good for this purpose, so I choose "str"...

  py::str dummyDataOwner;
  /*
   * Signature:
   array_t(ShapeContainer shape,
   StridesContainer strides,
   const T *ptr = nullptr,
   handle base = handle());
   */

  return py::array_t<T>(
      py::array::ShapeContainer({d.nframes, d.nchannels}), // Shape

      py::array::StridesContainer( // Strides
          {sizeof(T),
           sizeof(T) * d.nframes}), // Strides (in bytes) for each index

      reinterpret_cast<T *>(
          const_cast<DaqData &>(d).raw_ptr()), // Pointer to buffer

      dummyDataOwner // As stated above, now Numpy does not take ownership of
                     // the data pointer.
  );
}

template <typename T,bool copy=false> py::array_t<d> dmat_to_ndarray(const DaqData &d) {
  // https://github.com/pybind/pybind11/issues/323
  //
  // When a valid object is passed as 'base', it tells pybind not to take
  // ownership of the data, because 'base' will own it. In fact 'packet' will
  // own it, but - psss! - , we don't tell it to pybind... Alos note that ANY
  // valid object is good for this purpose, so I choose "str"...

  py::str dummyDataOwner;
  /*
   * Signature:
   array_t(ShapeContainer shape,
   StridesContainer strides,
   const T *ptr = nullptr,
   handle base = handle());
   */

  return py::array_t<T>(
      py::array::ShapeContainer({d.nframes, d.nchannels}), // Shape

      py::array::StridesContainer( // Strides
          {sizeof(T),
           sizeof(T) * d.nframes}), // Strides (in bytes) for each index

      reinterpret_cast<T *>(
          const_cast<DaqData &>(d).raw_ptr()), // Pointer to buffer

      dummyDataOwner // As stated above, now Numpy does not take ownership of
                     // the data pointer.
  );
}

/**
 * @brief Wraps the InDataHandler such that it calls a Python callback with a
 * buffer of sample data. The Python callback is called from a different
 * thread, using a Numpy array as argument.
 */
class PyIndataHandler : public ThreadedInDataHandler {
  /**
   * @brief The callback functions that is called.
   */
  py::function cb, reset_callback;

public:
  PyIndataHandler(StreamMgr &mgr, py::function cb, py::function reset_callback)
      : ThreadedInDataHandler(mgr), cb(cb), reset_callback(reset_callback) {

    DEBUGTRACE_ENTER;
    /// Start should be called externally, as at constructor time no virtual
    /// functions should be called.
    /* start(); */
  }
  ~PyIndataHandler() {
    DEBUGTRACE_ENTER;
    stop();
  }
  void reset(const Daq *daq) override final { reset_callback(daq); }

  /**
   * @brief Reads from the buffer
   */
  bool inCallback_threaded(const DaqData &d) override final {

    /* DEBUGTRACE_ENTER; */

    using DataType = DataTypeDescriptor::DataType;

    py::gil_scoped_acquire acquire;
    try {
      py::object bool_val;
      switch (d.dtype) {
      case (DataType::dtype_int8): {
        bool_val = cb(getPyArrayNoCpy<int8_t>(d));
      } break;
      case (DataType::dtype_int16): {
        bool_val = cb(getPyArrayNoCpy<int16_t>(d));
      } break;
      case (DataType::dtype_int32): {
        bool_val = cb(getPyArrayNoCpy<int32_t>(d));
      } break;
      case (DataType::dtype_fl32): {
        bool_val = cb(getPyArrayNoCpy<float>(d));
      } break;
      case (DataType::dtype_fl64): {
        bool_val = cb(getPyArrayNoCpy<double>(d));
      } break;
      default:
        throw std::runtime_error("BUG");
      } // End of switch

      bool res = bool_val.cast<bool>();
      if (!res)
        return false;
    } catch (py::error_already_set &e) {
      cerr << "ERROR: Python raised exception from callback function: ";
      cerr << e.what() << endl;
      return false;
    } catch (py::cast_error &e) {
      cerr << e.what() << endl;
      cerr << "ERROR: Python callback does not return boolean value." << endl;
      return false;
    }
    return true;
  }
};

void init_datahandler(py::module &m) {

  py::class_<InDataHandler> idh(m, "InDataHandler_base");
  idh.def("start", &InDataHandler::start);
  idh.def("stop", &InDataHandler::stop);

  py::class_<ThreadedInDataHandler, InDataHandler> tidh(
      m, "ThreadedInDataHandler");

  /// The C++ class is PyIndataHandler, but for Python, it is called
  /// InDataHandler
  py::class_<PyIndataHandler, ThreadedInDataHandler> pyidh(m, "InDataHandler");
  pyidh.def(py::init<StreamMgr &, py::function, py::function>());

  /// Peak Programme Meter
  py::class_<PPMHandler, ThreadedInDataHandler> ppm(m, "PPMHandler");
  ppm.def(py::init<StreamMgr &, const d>());
  ppm.def(py::init<StreamMgr &>());

  ppm.def("getCurrentValue", [](const PPMHandler &ppm) {
    std::tuple<vd, arma::uvec> tp = ppm.getCurrentValue();

    return py::make_tuple(carma::col_to_arr(std::get<0>(tp)),
                          carma::col_to_arr(std::get<1>(tp)));
  });

  /// Real time Aps
  ///
  py::class_<RtAps, ThreadedInDataHandler> rtaps(m, "RtAps");
  rtaps.def(py::init<StreamMgr &,              // StreamMgr
                     Filter *const,            // FreqWeighting filter
                     const us,                 // Nfft
                     const Window::WindowType, // Window
                     const d,                  // Overlap percentage 0<=o<100

                     const d // Time constant
                     >(),
            py::arg("streammgr"), // StreamMgr
            py::arg("preFilter").none(true),
            /// Below list of arguments *SHOULD* be same as for

            /// AvPowerSpectra constructor!
            py::arg("nfft") = 2048,                           //
            py::arg("windowType") = Window::WindowType::Hann, //
            py::arg("overlap_percentage") = 50.0,             //
            py::arg("time_constant") = -1                     //
  );

  rtaps.def("getCurrentValue", [](RtAps &rt) {
    std::unique_ptr<cube> val = rt.getCurrentValue();
    if (val) {
      return carma::cube_to_arr<c>(std::move(*val));
    }
    return carma::cube_to_arr<c>(cube(1, 0, 0));
  });
}