DerivedPseudoJetHelper.hh

//STARTHEADER
// $Id: DerivedPseudoJetHelper.hh 1885 2011-01-27 14:50:21Z salam $
//
// Copyright (c) 2005-2010, Matteo Cacciari, Gavin Salam and Gregory Soyez
//
//----------------------------------------------------------------------
// This file is part of FastJet.
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//  FastJet is free software; you can redistribute it and/or modify
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#ifndef __DERIVED_PSEUDOJET_HELPER_HH__
#define __DERIVED_PSEUDOJET_HELPER_HH__

#include "fastjet/internal/numconsts.hh"

FASTJET_BEGIN_NAMESPACE

//-------------------------------------------------------------------
// since C++ does not support partial specialisation of template
// member functions, we shall need an extra class that actually does
// the job (partial spec is allowed in the case of a class)
//-------------------------------------------------------------------

// fwd declaration of PJ
class PseudoJet;

/// \if internal_doc
/// @ingroup internal
/// \class DerivedPseudoJetHelper
/// Template helper to see if a class is derived from PseudoJet
/// (default version)
///
/// This template construct depends on a type and a boolean value.  we
/// shall implement a generic definition that is supposed to hold for a
/// type T that just has T[0--3] and, below, specialise it to the case
/// where T inherits from PseudoJet, thus giving access to more
/// information
/// \endif
template<typename T, bool b>
class DerivedPseudoJetHelper{
public:
  // ctor
  DerivedPseudoJetHelper(const T &t){ _t = &t;};

  // conversion to PJ*
  PseudoJet * operator()(){
    return NULL;
  }

protected:
  // a pointer to the actual data (we can use a pointer as it's always
  // going to be a temporary object
  const T* _t; 
};


/// \if internal_doc
/// @ingroup internal
/// specialisation for the case where T is derived from a PseudoJet
/// the default handler that does not support extra info
/// \endif
template<typename T>
class DerivedPseudoJetHelper<T, true>{
public:
  // ctor
  DerivedPseudoJetHelper(const T &t){ _t = &t;};

  // conversion to PJ*
  PseudoJet * operator()(){
    return _t;
  }
  
protected:
  // a pointer to the actual data (we can use a pointer as it's always
  // going to be a temporary object
  const T* _t;
};


FASTJET_END_NAMESPACE

#endif  // __DERIVED_PSEUDOJET_HELPER_HH__