pycallback_object.h

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/* -*- c++ -*- */
/*
 * Copyright 2012 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio
 *
 * GNU Radio is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3, or (at your option)
 * any later version.
 *
 * GNU Radio is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Radio; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include <iostream>
#include <gnuradio/rpcregisterhelpers.h>
#include <pythread.h>
#include <boost/format.hpp>

enum pyport_t {
  PYPORT_STRING,
  PYPORT_FLOAT
};

int pycallback_object_count = 500;

// a simple to-PMT converter template class-function
template <class myType> class pmt_assist
{
public:
  static pmt::pmt_t make(myType _val)
  {
    return pmt::mp(_val);
  }
};

/* template specializations for vectors that cant use pmt::mp() */
template<>
pmt::pmt_t pmt_assist<std::vector<float> >::make(std::vector<float> _val)
{
  return pmt::init_f32vector(_val.size(), &_val[0]);
}

template<>
pmt::pmt_t pmt_assist<std::vector<gr_complex> >::make(std::vector<gr_complex> _val)
{
  return pmt::init_c32vector(_val.size(), &_val[0]);
}

template <class myType> class pycallback_object
{
public:
  pycallback_object(std::string name, std::string functionbase,
            std::string units, std::string desc,
            myType min, myType max, myType deflt,
            DisplayType dtype) :
    d_callback(NULL),
    d_functionbase(functionbase), d_units(units), d_desc(desc),
    d_min(min), d_max(max), d_deflt(deflt), d_dtype(dtype),
    d_name(name), d_id(pycallback_object_count++)
  {
    d_callback = NULL;
    setup_rpc();
  }

  void add_rpc_variable(rpcbasic_sptr s)
  {
    d_rpc_vars.push_back(s);
  }

  myType get() {
    myType rVal = d_deflt;
    if(d_callback == NULL) {
      printf("WARNING: pycallback_object get() called without py callback set!\n");
      return rVal;
    }
    else {
      // obtain  PyGIL
      PyGILState_STATE state = PyGILState_Ensure();

      PyObject *func;
      //PyObject *arglist;
      PyObject *result;

      func = (PyObject *) d_callback;               // Get Python function
      //arglist = Py_BuildValue("");             // Build argument list
      result = PyEval_CallObject(func,NULL);     // Call Python
      //result = PyEval_CallObject(func,arglist);     // Call Python
      //Py_DECREF(arglist);                           // Trash arglist
      if(result) {                                 // If no errors, return double
        rVal = pyCast(result);
      }
      Py_XDECREF(result);

      // release  PyGIL
      PyGILState_Release(state);
      return rVal;
    }
  }

  void set_callback(PyObject *cb)
  {
    d_callback = cb;
  }

  void setup_rpc()
  {
#ifdef GR_CTRLPORT
    add_rpc_variable(
      rpcbasic_sptr(new rpcbasic_register_get<pycallback_object, myType>(
        (boost::format("%s%d") % d_name % d_id).str() , d_functionbase.c_str(),
        this, &pycallback_object::get, pmt_assist<myType>::make(d_min),
        pmt_assist<myType>::make(d_max), pmt_assist<myType>::make(d_deflt),
        d_units.c_str(), d_desc.c_str(), RPC_PRIVLVL_MIN, d_dtype)));
#endif /* GR_CTRLPORT */
  }

private:
  PyObject* d_callback;
  std::string d_functionbase, d_units, d_desc;
  myType d_min, d_max, d_deflt;
  DisplayType d_dtype;

  /* This is a fall-through converter in case someone tries to call pyCast on an
   * object type for which there isn't a template specialization (located below
   * this class) function. This function should never get called, and it is
   * unknown if changing the return type from myType to 'void' will break
   * something. */
  myType pyCast(PyObject* obj) {
    printf("TYPE NOT IMPLEMENTED!\n");
    assert(0);
    // the following is to make compilers happy only.
    myType dummy;
    return(dummy);
  };

  std::vector<boost::any> d_rpc_vars; // container for all RPC variables
  std::string d_name;
  int d_id;
};


// template specialization conversion functions
// get data out of the PyObject and into the real world
template<>
std::string pycallback_object<std::string>::pyCast(PyObject* obj)
{
  return std::string(PyString_AsString(obj));
}

template<>
double pycallback_object<double>::pyCast(PyObject* obj)
{
  return PyFloat_AsDouble(obj);
}

template<>
float pycallback_object<float>::pyCast(PyObject* obj)
{
  return (float)PyFloat_AsDouble(obj);
}

template<>
int pycallback_object<int>::pyCast(PyObject* obj)
{
  return PyInt_AsLong(obj);
}

template<>
std::vector<float> pycallback_object<std::vector<float> >::pyCast(PyObject* obj)
{
  int size = PyObject_Size(obj);
  std::vector<float> rval(size);
  for(int i=0; i<size; i++) {
    rval[i] = (float)PyFloat_AsDouble(PyList_GetItem(obj, i));
  }
  return rval;
}

template<>
std::vector<gr_complex> pycallback_object<std::vector<gr_complex> >::pyCast(PyObject* obj)
{
  int size = PyObject_Size(obj);
  std::vector<gr_complex> rval(size);
  for(int i=0; i<size; i++){ rval[i] = \
      gr_complex((float)PyComplex_RealAsDouble(PyList_GetItem(obj, i)),
                 (float)PyComplex_ImagAsDouble(PyList_GetItem(obj, i)));
  }
  return rval;
}
// TODO: add more template specializations as needed!