MethodVar.cxx

Go to the documentation of this file.

//*-- Author :    Ole Hansen   18/2/2016
 
//
// MethodVar
//
// A "global variable" referencing a class member function call
//
 
#include "MethodVar.h"
#include "THaVar.h"
#include "TError.h"
#include "TMethodCall.h"
#include <cstring> // for memcpy
#include <cassert>
#include <cmath>
#include <limits>
 
using namespace std;
 
namespace Podd {
 
//_____________________________________________________________________________
MethodVar::MethodVar( THaVar* pvar, const void* addr,
                      VarType type, TMethodCall* method )
  : Variable(pvar,addr,type), fMethod(method), fData(0)
{
  // Constructor
  assert( fMethod );
 
  if( !VerifyNonArrayName(GetName()) ) {
    fValueP = nullptr;
    return;
  }
}
 
//_____________________________________________________________________________
MethodVar::~MethodVar()
{
  // Destructor
 
  delete fMethod;
}
 
//_____________________________________________________________________________
const void* MethodVar::GetDataPointer( Int_t i ) const
{
  // Get pointer to data via method call on the object pointed to by fValueP.
  // Requesting "elements" other than i==0 is not allowed.
 
  const char* const here = "GetDataPointer()";
 
  assert( fValueP );
  assert( fMethod );
 
  if( i != 0 ) {
    fSelf->Error( here, "Index out of range, variable %s, index %d", GetName(), i );
    return nullptr;
  }
 
  return GetDataPointer(fValueP);
}
 
//_____________________________________________________________________________
const void* MethodVar::GetDataPointer( const void* obj ) const
{
  // Make the method call on the object pointed to by 'obj'
 
  void* pobj = const_cast<void*>(obj);  // TMethodCall wants a non-const object...
 
  if( IsFloat() ) {
    // Floating-point data
    Double_t result;
    fMethod->Execute( pobj, result );
    switch( fType ) {
    case kDouble:
      fData = result;
      break;
    case kFloat:
      {
        // The data here must fit without overflow, otherwise the interpreter
        // lied to us when it gave us the function return type
        assert( fabs(result) <= numeric_limits<float>::max() );
 
        // The conversion could be done in a single assignment,
        //*reinterpret_cast<Float_t*>(&fData) = result;
        //but it's more readable and perhaps more portable this way
        Float_t resultF = result;
        memcpy( &fData, &resultF, sizeof(resultF) );
      }
      break;
    default:
      assert(false);  // ill-constructed object (error in THaVarList::DefineByRTTI)
    }
    return &fData;
  }
  else {
    // Integer data
    Long_t result;  // TMethodCall really wants Long_t, not Long64_t
    fMethod->Execute( pobj, result );
    switch( fType ) {
    case kLong:
    case kULong:
      memcpy( &fData, &result, sizeof(result) );
      break;
    case kInt:
    case kUInt:
      {
        Int_t resultI = result;
        memcpy( &fData, &resultI, sizeof(resultI) );
      }
      break;
    case kShort:
    case kUShort:
      {
        Short_t resultS = result;
        memcpy( &fData, &resultS, sizeof(resultS) );
      }
      break;
    case kChar:
    case kUChar:
      {
        Char_t resultC = result;
        memcpy( &fData, &resultC, sizeof(resultC) );
      }
      break;
    default:
      assert(false);  // ill-constructed object (error in THaVarList::DefineByRTTI)
    }
    return &fData;
  }
  // Not reached
  return nullptr;
}
 
//_____________________________________________________________________________
Bool_t MethodVar::IsBasic() const
{
  // Data are basic (POD variable or array)
 
  return false;
}
 
//_____________________________________________________________________________
 
}// namespace Podd