JROOT::JTreeWriter< T, true > Class Template Reference

Template specialisation for flat template TTree writing. More...

#include <JTreeWriter.hh>

Inheritance diagram for JROOT::JTreeWriter< T, true >:

Public Member Functions
	JTreeWriter (const JTreeParameters &parameters)
	Constructor.
Int_t	Write (const T &object)
	Data object output equivalent of TTree::Fill().

Private Attributes
std::vector< TBranch * >	branches_
std::vector< Long_t >	offsets_

Detailed Description

template<class T>
class JROOT::JTreeWriter< T, true >

Template specialisation for flat template TTree writing.

Definition at line 104 of file JTreeWriter.hh.

Constructor & Destructor Documentation

JTreeWriter()

template<class T >

JROOT::JTreeWriter< T, true >::JTreeWriter ( const JTreeParameters & parameters )

inline

Constructor.

Parameters

parameters

parameters of TTree

Definition at line 112 of file JTreeWriter.hh.

    {
      SetNameTitle(parameters.getTreeName(), parameters.getTreeTitle());
 
      // if more than one branch, check those are the data members of T
 
      TClass* t_class = TClass::GetClass<T>();
 
      if (t_class == nullptr) {
        THROW(JException, "Could not get class " << typeid(T).name());
      }
 
      TIter      next(t_class->GetListOfRealData());
      TRealData* data{nullptr};
      T          object;
 
      auto* base = reinterpret_cast<uint8_t*>(&object);
 
      while ((data = dynamic_cast<TRealData*>(next())) != nullptr) {
 
        if (!JRoot::is_tobject_member(data->GetName())) {
 
          auto*       member    = data->GetDataMember();
          auto*       address   = reinterpret_cast<uint8_t*>(base + member->GetOffset());
          std::string type_name = data->GetDataMember()->GetTypeName();
 
          if (member->GetArrayDim() > 0) {
            type_name += "[]";
          }
 
          std::string type_code = JRootPrimitiveTypes::getTypeCode(type_name);
 
          if (type_code.empty()) {
            THROW(JException, "unknown type " << type_name);
          }
 
          std::string leaf = data->GetName();
          leaf += "/" + type_code;
          auto branch = Branch(data->GetName(), address, leaf.c_str());
 
          branches_.push_back(branch);
          offsets_ .push_back(member->GetOffset());
        }
      }
    }

Member Function Documentation

Write()

template<class T >

Int_t JROOT::JTreeWriter< T, true >::Write ( const T & object )

inline

Data object output equivalent of TTree::Fill().

Parameters

object

data object

Returns

as TTree::Fill

Definition at line 164 of file JTreeWriter.hh.

    {
      auto* base = const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(&object));
 
      for (size_t i = 0; i < branches_.size(); i++) {
        branches_[i]->SetAddress(reinterpret_cast<uint8_t*>(base + offsets_[i]));
      }
 
      return this->Fill();
    }

Member Data Documentation

branches_

template<class T >

std::vector<TBranch*> JROOT::JTreeWriter< T, true >::branches_

private

Definition at line 179 of file JTreeWriter.hh.

offsets_

template<class T >

std::vector<Long_t> JROOT::JTreeWriter< T, true >::offsets_

private

Definition at line 181 of file JTreeWriter.hh.

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The documentation for this class was generated from the following file:

• JTreeWriter.hh