Helpers.h

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#ifndef GAUDIPYTHON_HELPERS_H
#define GAUDIPYTHON_HELPERS_H

// Framework
#include "GaudiKernel/IAlgManager.h"
#include "GaudiKernel/IAlgorithm.h"
#include "GaudiKernel/IAlgTool.h"

#ifdef _POSIX_C_SOURCE
#undef _POSIX_C_SOURCE
#endif
#include "Python.h"

#if PY_VERSION_HEX < 0x02050000
// Note (MCl):
// In Python 2.5, all the functions working with lenghts use the type PySsize_t
// instead of int. The also changed the name of the typedefs for those functions.
// Here we use:
//  intargfunc -> ssizeargfunc
//  inquiry    -> lenfunc
//
typedef int Py_ssize_t;
#endif

// the following is done instead of including Python.h becuase there is
// a clash with codecs.h defined in Python and the one in VC++ 7.1
//struct _object;
//typedef _object PyObject;
//extern "C" {
//  PyObject* PyBuffer_FromMemory( void *ptr, int size);
//}

namespace GaudiPython {

struct Helper {
  // This is a number of static functions to overcome the current problem with PyLCGDict that
  // does not allow to return instances of complex objects by calling arguments
  // (reference to pointers)
  Helper() {}
  // Provided for backward compatibility
  static IService* service(ISvcLocator* svcloc, const std::string& name, bool createif=false) {
    return svcloc->service(name, createif).get();
  }
  // Provided for backward compatibility
  static IAlgorithm* algorithm(IAlgManager* algmgr, const std::string& name) {
    const bool createIf = false;
    return algmgr->algorithm(name, createIf).get();
  }
  static DataObject* dataobject(IDataProviderSvc* dpsvc, const std::string& path ) {
    DataObject* o;
    if ( dpsvc->retrieveObject(path,o).isSuccess() ) return o;
    else return 0;
  }
  static IAlgTool* tool(IToolSvc* toolsvc, const std::string& type, const std::string& name, IInterface* p, bool cif ) {
    IAlgTool* o;
    if ( toolsvc->retrieve(type, name, IAlgTool::interfaceID(), o, p, cif).isSuccess() ) return o;
    else return 0;
  }
  static long loadDynamicLib(const std::string& name) {
    void* h;
    return System::loadDynamicLib(name, &h);
  }
  static IHistogram1D* histo1D( IHistogramSvc* hsvc, const std::string& path ) {
    IHistogram1D* h;
    if ( hsvc->findObject(path, h ).isSuccess() ) return h;
    else                                          return 0;
  }
  static IHistogram2D* histo2D( IHistogramSvc* hsvc, const std::string& path ) {
    IHistogram2D* h;
    if ( hsvc->findObject(path, h ).isSuccess() ) return h;
    else                                          return 0;
  }
  static IHistogram3D* histo3D( IHistogramSvc* hsvc, const std::string& path ) {
    IHistogram3D* h;
    if ( hsvc->findObject(path, h ).isSuccess() ) return h;
    else                                          return 0;
  }
  static IProfile1D*
  profile1D
  ( IHistogramSvc*     hsvc ,
    const std::string& path )
  {
    IProfile1D* h = 0 ;
    if ( 0 != hsvc && hsvc->findObject ( path , h ).isSuccess() ) { return h ; }
    return 0 ;
  }
  static IProfile2D*
  profile2D
  ( IHistogramSvc*     hsvc ,
    const std::string& path )
  {
    IProfile2D* h = 0 ;
    if ( 0 != hsvc && hsvc->findObject ( path , h ).isSuccess() ) { return h ; }
    return 0 ;
  }
// Array support
private:
  template <class T>
  static Py_ssize_t Array_length( PyObject* self ) {
#if PY_VERSION_HEX < 0x02050000
    const
#endif
    char* buf = 0;
    Py_ssize_t size = (*(self->ob_type->tp_as_buffer->bf_getcharbuffer))( self, 0, &buf );
    return size/sizeof(T);
  }

  template <class T> static PyObject* toPython(T* o) { return 0; }
  static PyObject* toPython(int* o) { return PyInt_FromLong((long)*o); }
  static PyObject* toPython(short* o) { return PyInt_FromLong((long)*o); }
  static PyObject* toPython(char* o) { return PyInt_FromLong((long)*o); }
  static PyObject* toPython(long* o) { return PyInt_FromLong(*o); }
  static PyObject* toPython(float* o) { return PyFloat_FromDouble((double)*o); }
  static PyObject* toPython(double* o) { return PyFloat_FromDouble(*o); }

  template <class T>
  static PyObject* Array_item( PyObject* self, Py_ssize_t idx ) {
#if PY_VERSION_HEX < 0x02050000
    const
#endif
    char* buf = 0;
    Py_ssize_t size = (*(self->ob_type->tp_as_buffer->bf_getcharbuffer))( self, 0, &buf );
    if ( idx < 0 || idx >= size/int(sizeof(T)) ) {
       PyErr_SetString( PyExc_IndexError, "buffer index out of range" );
       return 0;
    }
    return toPython((T*)buf + idx);
  }

public:
  template <class T>
  static PyObject* toArray( T* ptr, Py_ssize_t size ) {
   static PyTypeObject      type = PyBuffer_Type;
   static PySequenceMethods meth = *(PyBuffer_Type.tp_as_sequence);
#if PY_VERSION_HEX < 0x02050000
   meth.sq_item         = (intargfunc) &Array_item<T>;
   meth.sq_length       = (inquiry) &Array_length<T>;
#else
   meth.sq_item         = (ssizeargfunc) &Array_item<T>;
   meth.sq_length       = (lenfunc) &Array_length<T>;
#endif
   type.tp_as_sequence  = &meth;
   PyObject* buf = PyBuffer_FromReadWriteMemory( ptr, size*sizeof(T) );
   Py_INCREF( &type );
   buf->ob_type = &type;
   return buf;
  }
  static PyObject* toIntArray    ( void* ptr, Py_ssize_t size ) { return toArray( (int*)    ptr , size ); }
  static PyObject* toShortArray  ( void* ptr, Py_ssize_t size ) { return toArray( (short*)  ptr , size ); }
  static PyObject* toFloatArray  ( void* ptr, Py_ssize_t size ) { return toArray( (float*)  ptr , size ); }
  static PyObject* toDoubleArray ( void* ptr, Py_ssize_t size ) { return toArray( (double*) ptr , size ); }

  template <class T>
  static T* toAddress( std::vector<T>& v ) {
    return &(*v.begin());
  }
  template <class T>
  static T* toAddress( void * a) {
    return (T*)a;
  }

};

template PyObject* Helper::toArray(int*,Py_ssize_t);
template PyObject* Helper::toArray(char*,Py_ssize_t);
template PyObject* Helper::toArray(short*,Py_ssize_t);
template PyObject* Helper::toArray(float*,Py_ssize_t);
template PyObject* Helper::toArray(double*,Py_ssize_t);
template int* Helper::toAddress(std::vector<int>&);
template float* Helper::toAddress(std::vector<float>&);
template double* Helper::toAddress(std::vector<double>&);
template int* Helper::toAddress<int>(void*);
template float* Helper::toAddress<float>(void*);
template double* Helper::toAddress<double>(void*);

} // namespace GaudiPython

#endif // !GAUDIPYTHON_HELPERS_H