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

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 can't use pmt::mp() */
template <>
pmt::pmt_t pmt_assist<std::vector<float>>::make(std::vector<float> _val)
{
    return pmt::init_f32vector(_val.size(), _val);
}

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

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<rpcbasic_sptr> 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!