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#ifndef G4CrossSectionFactory_h
#define G4CrossSectionFactory_h 1


#include "globals.hh"
#include "G4VCrossSectionDataSet.hh"
#include "G4CrossSectionFactoryRegistry.hh"
#include "G4Threading.hh"

class G4VBaseXSFactory
{
public:

  G4VBaseXSFactory()
  {
    fRegistry = G4CrossSectionFactoryRegistry::Instance();
  }
   
  virtual ~G4VBaseXSFactory() = default;

  virtual G4VCrossSectionDataSet* Instantiate() = 0;

protected:
  G4CrossSectionFactoryRegistry* fRegistry;
};

//Generic template XS-factory
template <typename T, int mode> class G4CrossSectionFactory : public G4VBaseXSFactory
{
public:
  G4CrossSectionFactory(const G4String& name)
  {
    fRegistry->Register(name, this);
  }

  G4VCrossSectionDataSet* Instantiate() override
  {
      G4ExceptionDescription msg;
      msg<<"Factory mode: "<<mode<<" not supported!";
      G4Exception("G4CrossSectionFactory::Instantiate","CrossSectionFactory001",FatalException,msg);
    return static_cast<T*>(0);
  }
};

//Partial specialized template for non-singleton non-shared factory
// each call to Instantiate creates a new XS
template <typename T> class G4CrossSectionFactory<T,0> : public G4VBaseXSFactory
{
public:
    
  G4CrossSectionFactory(const G4String& name)
  {
    fRegistry->Register(name, this);
  }

  G4VCrossSectionDataSet* Instantiate() override
  {
    return new T();
  }
};

//Partial specialized template for singleton, shared factory
// each call to Instantiate returns pointer to static object
template <typename T> class G4CrossSectionFactory<T,1> : public G4VBaseXSFactory
{
public:
  G4CrossSectionFactory(const G4String& name)
  {
    fRegistry->Register(name,this);
  }

  G4VCrossSectionDataSet* Instantiate() override
  {
    static T* shared = new T();
    return shared;
  }
};

//Partial specialized template for singleton, shared factory
// each call to Instantiate returns pointer to static thread-local object
template <typename T> class G4CrossSectionFactory<T,2> : public G4VBaseXSFactory
{
  G4CrossSectionFactory(const G4String& name)
  {
    fRegistry->Register(name,this);
  }

  G4VCrossSectionDataSet* Instantiate() override
  {
    static G4ThreadLocal T* shared = new T();
    return shared;
  }
};


#define G4_BASE_DECLARE_XS_FACTORY(cross_section, flag) \
  const G4CrossSectionFactory<cross_section,flag>& cross_section##Factory = G4CrossSectionFactory<cross_section,flag>(cross_section::Default_Name())

#define G4_BASE_REFERENCE_XS_FACTORY(cross_section,flag) \
  class cross_section; \
  extern const G4CrossSectionFactory<cross_section,flag>& cross_section##Factory; \
  const G4CrossSectionFactory<cross_section,flag>& cross_section##FactoryRef = cross_section##Factory

//Macros to help define and reference factories
#define G4_DECLARE_XS_FACTORY(cross_section) G4_BASE_DECLARE_XS_FACTORY(cross_section,0)
#define G4_DECLARE_SHAREDXS_FACTORY(cross_section) G4_BASE_DECLARE_XS_FACTORY(cross_section,1)
#define G4_DECLARE_SHAREDTLSXS_FACTORY(cross_section) G4_BASE_DECLARE_XS_FACTORY(cross_section,2)


#define G4_REFERENCE_XS_FACTORY(cross_section) G4_BASE_REFERENCE_XS_FACTORY(cross_section,0)
#define G4_REFERENCE_SHAREDXS_FACTORY(cross_section) G4_BASE_REFERENCE_XS_FACTORY(cross_section,1)
#define G4_REFERENCE_SHAREDTLSXS_FACTORY(cross_section) G4_BASE_REFERENCE_XS_FACTORY(cross_section,2)

#endif
