// Copyright (c) 2001  Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel).  All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $Source$
// $Revision$ $Date$
// $Name$
//
// Author(s)     : Andreas Fabri

#ifndef CGAL_LAZY_H
#define CGAL_LAZY_H

#include <CGAL/basic.h>
#include <CGAL/Handle.h>
#include <CGAL/Object.h>
#include <CGAL/Lazy_exact_nt.h>
#include <CGAL/Kernel/Type_mapper.h>
#include <CGAL/Profile_counter.h>

CGAL_BEGIN_NAMESPACE

template <typename AT, typename ET, typename EFT, typename E2A> class Lazy;





template <typename AT, typename ET, typename EFT, typename E2A>
inline
const AT&
approx(const Lazy<AT,ET, EFT, E2A>& l)
{
  return l.approx();
}


template <typename AT, typename ET, typename EFT, typename E2A>
inline
AT&
approx(Lazy<AT,ET, EFT, E2A>& l)
{
  return l.approx();
}


template <typename ET>
inline
const Interval_nt<false>&
approx(const Lazy_exact_nt<ET>& l)
{
  return l.approx();
}


inline
const double&
approx(const double& d)
{
  return d;
}

inline
const float&
approx(const float& f)
{
  return f;
}

inline
const int&
approx(const int& i)
{
  return i;
}

inline
const unsigned int&
approx(const unsigned int& i)
{
  return i;
}

inline
const Null_vector&
approx(const Null_vector& nv)
{
  return nv;
}

inline
const Null_vector&
exact(const Null_vector& nv)
{
  return nv;
}

inline
const Origin&
approx(const Origin& nv)
{
  return nv;
}

inline
const Origin&
exact(const Origin& nv)
{
  return nv;
}

inline
const Orientation&
approx(const Orientation& nv)
{
  return nv;
}

inline
const Orientation&
exact(const Orientation& nv)
{
  return nv;
}

template <typename AT, typename ET, typename EFT, typename E2A>
inline
const ET&
exact(const Lazy<AT,ET,EFT,E2A>& l)
{
  return l.exact();
}


template <typename ET>
inline
const ET&
exact(const Lazy_exact_nt<ET>& l)
{
  return l.exact();
}




inline
const double&
exact(const double& d)
{
  return d;
}

inline
const float&
exact(const float& f)
{
  return f;
}

inline
const int&
exact(const int& i)
{
  return i;
}

inline
const unsigned int&
exact(const unsigned int& i)
{
  return i;
}

template <typename AT, typename ET, typename EFT, typename E2A>
inline
void
print_dag(const Lazy<AT,ET,EFT,E2A>& l, std::ostream& os, int level = 0)
{
  l.print_dag(os, level);
}


//____________________________________________________________
// The rep for the leaf node

template <typename AT, typename ET, typename E2A> 
class Lazy_construct_rep_0 : public Lazy_construct_rep<AT, ET, E2A>
{

  typedef Lazy_construct_rep<AT, ET, E2A> Base;
public:

  void
  update_exact()
  {
    this->et = new ET();
  }

  Lazy_construct_rep_0()
    : Lazy_construct_rep<AT,ET, E2A>()
  {}

  Lazy_construct_rep_0(const AT& a, const ET& e)
    : Lazy_construct_rep<AT,ET,E2A>(a, e)
  {}
  
  Lazy_construct_rep_0(const AT& a, void*)
    : Lazy_construct_rep<AT,ET,E2A>(a)
  {}

  Lazy_construct_rep_0(const ET& e)
    : Lazy_construct_rep<AT,ET,E2A>(AT(), e)
  {  
    E2A e2a;
    this->at = e2a(e); 
  }

  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
  }
};


//____________________________________________________________

template <typename AC, typename EC, typename E2A, typename L1>
class Lazy_construct_rep_1 : public Lazy_construct_rep<typename AC::result_type, typename EC::result_type, E2A>
{
  typedef typename AC::result_type AT;
  typedef typename EC::result_type ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;

public:

  void
  update_exact()
  {
    this->et = new ET(ec_(CGAL::exact(l1_)));
    E2A()(*(this->et));
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
  }


  Lazy_construct_rep_1(const AC& ac, const EC& ec, const L1& l1)
    : Lazy_construct_rep<AT,ET, E2A>(ac(CGAL::approx(l1))), ec_(ec), l1_(l1)
  {}


#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const 
  {
    this->print_at_et(os, level);
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with one child node:");
      CGAL::print_dag(l1_, os, level+1);
    }
  }
#endif

};



//____________________________________________________________

template <typename AC, typename EC, typename E2A, typename L1, typename L2>
class Lazy_construct_rep_2 : public Lazy_construct_rep<typename AC::result_type , typename EC::result_type, E2A>
{
  typedef typename AC::result_type AT;
  typedef typename EC::result_type ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;
  L2 l2_;

public:

  void
  update_exact()
  {
    this->et = new ET(ec_(CGAL::exact(l1_), CGAL::exact(l2_)));
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
    l2_ = L2();
  }


  Lazy_construct_rep_2(const AC& ac, const EC& ec, const L1& l1, const L2& l2)
    : Lazy_construct_rep<AT,ET,E2A>(ac(CGAL::approx(l1), CGAL::approx(l2))), l1_(l1), l2_(l2)
  {}

#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with two child nodes:");
      CGAL::print_dag(l1_, os, level+1);
      CGAL::print_dag(l2_, os, level+1);
    }
  }
#endif
};



//____________________________________________________________

template <typename AC, typename EC, typename E2A, typename L1, typename L2, typename L3>
class Lazy_construct_rep_3 : public Lazy_construct_rep<typename AC::result_type , typename EC::result_type, E2A>
{
  typedef typename AC::result_type AT;
  typedef typename EC::result_type ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;
  L2 l2_;
  L3 l3_;

public:

  void
  update_exact()
  {
    this->et = new ET(ec_(CGAL::exact(l1_), CGAL::exact(l2_), CGAL::exact(l3_)));
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
    l2_ = L2();
    l3_ = L3();
  }


  Lazy_construct_rep_3(const AC& ac, const EC& ec, const L1& l1, const L2& l2, const L3& l3)
    : Lazy_construct_rep<AT,ET,E2A>(ac(CGAL::approx(l1), CGAL::approx(l2), CGAL::approx(l3))), l1_(l1), l2_(l2), l3_(l3)
  {}

#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with three child nodes:");
      CGAL::print_dag(l1_, os, level+1);
      CGAL::print_dag(l2_, os, level+1);
      CGAL::print_dag(l3_, os, level+1);
    }
  }
#endif
};


//____________________________________________________________

template <typename AC, typename EC, typename E2A, typename L1, typename L2, typename L3, typename L4>
class Lazy_construct_rep_4 : public Lazy_construct_rep<typename AC::result_type , typename EC::result_type, E2A>
{
  typedef typename AC::result_type AT;
  typedef typename EC::result_type ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;
  L2 l2_;
  L3 l3_;
  L4 l4_;

public:

  void
  update_exact()
  {
    this->et = new ET(ec_(CGAL::exact(l1_), CGAL::exact(l2_), CGAL::exact(l3_), CGAL::exact(l4_)));
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
    l2_ = L2();
    l3_ = L3();
    l4_ = L4();
  }

    
  Lazy_construct_rep_4(const AC& ac, const EC& ec, const L1& l1, const L2& l2, const L3& l3, const L4& l4)
   : Lazy_construct_rep<AT,ET,E2A>(ac(CGAL::approx(l1), CGAL::approx(l2), CGAL::approx(l3), CGAL::approx(l4))), l1_(l1), l2_(l2), l3_(l3), l4_(l4)
  {}


#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
    
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with four child nodes:");
      CGAL::print_dag(l1_, os, level+1);
      CGAL::print_dag(l2_, os, level+1);
      CGAL::print_dag(l3_, os, level+1);
      CGAL::print_dag(l4_, os, level+1);
    }
  }
#endif
};

//____________________________________________________________


template <typename AC, typename EC, typename E2A, typename L1, typename L2, typename L3, typename L4, typename L5>
 class Lazy_construct_rep_5 : public Lazy_construct_rep<typename AC::result_type , typename EC::result_type, E2A>
{
  typedef typename AC::result_type AT;
  typedef typename EC::result_type ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;
  L2 l2_;
  L3 l3_;
  L4 l4_;
  L5 l5_;

public:

  void
  update_exact()
  {
    this->et = new ET(ec_(CGAL::exact(l1_), CGAL::exact(l2_), CGAL::exact(l3_), CGAL::exact(l4_), CGAL::exact(l5_)));
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
    l2_ = L2();
    l3_ = L3();
    l4_ = L4();
    l5_ = L5();
  }

 Lazy_construct_rep_5(const AC& ac, const EC& ec, const L1& l1, const L2& l2, const L3& l3, const L4& l4, const L5& l5)
    : Lazy_construct_rep<AT,ET,E2A>(ac(CGAL::approx(l1), CGAL::approx(l2), CGAL::approx(l3), CGAL::approx(l4), CGAL::approx(l5))), l1_(l1), l2_(l2), l3_(l3), l4_(l4), l5_(l5)
  {}

#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
    
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with five child nodes:");
      CGAL::print_dag(l1_, os, level+1);
      CGAL::print_dag(l2_, os, level+1);
      CGAL::print_dag(l3_, os, level+1);
      CGAL::print_dag(l4_, os, level+1);
      CGAL::print_dag(l5_, os, level+1);
    }
  }
#endif
};

struct Approx_converter {
  template < typename T >
  const typename T::AT&
  operator()(const T&t) const
  { return t.approx(); }

  const Null_vector&
  operator()(const Null_vector& n) const
  { return n; }

};

struct Exact_converter {
  template < typename T >
  const typename T::ET&
  operator()(const T&t) const
  { return t.exact(); }

  const Null_vector&
  operator()(const Null_vector& n) const
  { return n; }
};

//____________________________________________________________



template <typename AC, typename EC, typename E2A, typename L1>
class Lazy_construct_rep_with_vector_1 : public Lazy_construct_rep<std::vector<Object> , std::vector<Object>, E2A>
{
  typedef std::vector<Object> AT;
  typedef std::vector<Object> ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;


public:

  void
  update_exact()
  {
   std::vector<Object> vec;
    this->et = new ET();
    //this->et->reserve(this->at.size()); 
    ec_(CGAL::exact(l1_), std::back_inserter(*(this->et)));
    if(this->et==NULL)
    E2A()(*(this->et)); 
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
  }


  Lazy_construct_rep_with_vector_1(const AC& ac, const EC& ec, const L1& l1)
    : l1_(l1)
  {
    ac(CGAL::approx(l1), std::back_inserter(this->at));
  }

#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
    os << "A Lazy_construct_rep_with_vector_1 of size " <<  this->at.size() << std::endl;
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with one child node:");
      CGAL::print_dag(l1_, os, level+1);

    }
  }
#endif
};






template <typename AC, typename EC, typename E2A, typename L1, typename L2>
class Lazy_construct_rep_with_vector_2
   : public Lazy_construct_rep<std::vector<Object> , std::vector<Object>, E2A>
{
  typedef std::vector<Object> AT;
  typedef std::vector<Object> ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;
  L2 l2_;

public:

  void
  update_exact()
  {
    this->et = new ET();
    this->et->reserve(this->at.size());
    ec_(CGAL::exact(l1_), CGAL::exact(l2_), std::back_inserter(*(this->et))); 
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
    l2_ = L2();
  }


  Lazy_construct_rep_with_vector_2(const AC& ac, const EC& ec, const L1& l1, const L2& l2)
    : l1_(l1), l2_(l2)
  {
    ac(CGAL::approx(l1), CGAL::approx(l2), std::back_inserter(this->at));
  }

#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
    os << "A Lazy_construct_rep_with_vector_2 of size " <<  this->at.size() << std::endl;
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with two child nodes:");
      CGAL::print_dag(l1_, os, level+1);
      CGAL::print_dag(l2_, os, level+1);
    }
  }
#endif
};




template <typename AC, typename EC, typename E2A, typename L1, typename L2, typename R1>
class Lazy_construct_rep_2_1 : public Lazy_construct_rep<typename R1::AT , typename R1::ET, E2A>
{
  typedef typename R1::AT AT;
  typedef typename R1::ET ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;
  L2 l2_;
public:

  void
  update_exact()
  {
    this->et = new ET();
    ec_(CGAL::exact(l1_), CGAL::exact(l2_), *(this->et));
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
    l2_ = L2();
  }


  Lazy_construct_rep_2_1(const AC& ac, const EC& ec, const L1& l1, const L2& l2)
    : Lazy_construct_rep<AT,ET,E2A>(), l1_(l1), l2_(l2)
  {
    ac(CGAL::approx(l1), CGAL::approx(l2), this->at);
  }


#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
    os << "A Lazy_construct_rep_2_1" << std::endl;
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with two child nodes:");
      CGAL::print_dag(l1_, os, level+1);
      CGAL::print_dag(l2_, os, level+1);
    }
  }
#endif
};


//____________________________________________________________________________________
// The following rep class stores two non-const reference parameters of type R1 and R2


template <typename AC, typename EC, typename E2A, typename L1, typename L2, typename R1, typename R2>
class Lazy_construct_rep_2_2 : public Lazy_construct_rep<std::pair<typename R1::AT,typename R2::AT> , std::pair<typename R1::ET, typename R2::ET>, E2A>
{
  typedef std::pair<typename R1::AT, typename R2::AT> AT;
  typedef std::pair<typename R1::ET, typename R2::ET> ET;
  typedef Lazy_construct_rep<AT, ET, E2A> Base;

  EC ec_;
  L1 l1_;
  L2 l2_;
public:

  void
  update_exact()
  {
    this->et = new ET();
    ec_(CGAL::exact(l1_), CGAL::exact(l2_), this->et->first, this->et->second );
    this->at = E2A()(*(this->et));
    // Prune lazy tree
    l1_ = L1();
    l2_ = L2();
  }


  Lazy_construct_rep_2_2(const AC& ac, const EC& ec, const L1& l1, const L2& l2)
    : Lazy_construct_rep<AT,ET,E2A>(), l1_(l1), l2_(l2)
  {
    ac(CGAL::approx(l1), CGAL::approx(l2), this->at.first, this->at.second);
  }

#ifdef CGAL_LAZY_KERNEL_DEBUG
  void
  print_dag(std::ostream& os, int level) const
  {
    this->print_at_et(os, level);
    os << "A Lazy_construct_rep_2_2"  << std::endl;
    if(this->is_lazy()){
      CGAL::msg(os, level, "DAG with two child nodes:");
      CGAL::print_dag(l1_, os, level+1);
      CGAL::print_dag(l2_, os, level+1);
    }
  }
#endif
};



//____________________________________________________________
// The handle class
template <typename AT_, typename ET_, typename EFT, typename E2A>
class Lazy : public Handle
{
public :
  typedef AT_ AT;
  typedef ET_ ET;
  typedef Lazy<AT, ET, EFT, E2A> Self;
  typedef Lazy_construct_rep<AT, ET, E2A> Self_rep;

  typedef Self Rep;

  const Rep& rep() const
  {
    return *this;
  }

  Rep& rep()
  {
    return *this;
  }

  Lazy()
  {
    PTR = new Lazy_construct_rep_0<AT,ET, E2A>();
  }
  
  Lazy (Self_rep *r)
  { 
    PTR = r; 
  }
  
  const AT& approx() const 
  { return ptr()->approx(); }


  const ET&  exact() const
  { return ptr()->exact(); }
  
  
   AT& approx()  
  { return ptr()->approx(); }


  ET&  exact() 
  { return ptr()->exact(); }

  int depth() const
  {
    return ptr()->depth();
  }

  void print_dag(std::ostream& os, int level) const
  {
    ptr()->print_dag(os, level);
  }


private:
  Self_rep * ptr() const { return (Self_rep*) PTR; }

};





// The magic functor for Construct_bbox_[2,3], as there is no Lazy<Bbox>

template <typename LK, typename AC, typename EC>
struct Lazy_construction_bbox {
  static const bool Protection  = true;
  typedef typename LK::AK AK;
  typedef typename LK::EK EK;
  typedef typename AC::result_type result_type;

  AC ac;
  EC ec;
  template <typename L1>
  result_type operator()(const L1& l1) const
  {
    try {
       CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      return ac(CGAL::approx(l1));
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return ec(CGAL::exact(l1));
    }
  }
};

template <typename LK, typename AC, typename EC>
struct Lazy_construction_nt {

  static const bool Protection  = true;

  typedef typename LK::AK AK;
  typedef typename LK::EK EK;
  typedef typename LK::E2A E2A;
  typedef typename AC::result_type AT;
  typedef typename EC::result_type ET;
  typedef Lazy_exact_nt<ET> result_type;

  AC ac;
  EC ec;
  template <typename L1>
  result_type operator()(const L1& l1) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      return new Lazy_construct_rep_1<AC, EC, To_interval<ET>, L1>(ac, ec, l1);
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return new Lazy_construct_rep_0<AT,ET,To_interval<ET> >(ec(CGAL::exact(l1)));
    }
  }

  template <typename L1, typename L2>
  result_type operator()(const L1& l1, const L2& l2) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      return new Lazy_construct_rep_2<AC, EC, To_interval<ET>, L1,L2>(ac, ec, l1,l2);
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return new Lazy_construct_rep_0<AT,ET,To_interval<ET> >(ec(CGAL::exact(l1), exact(l2)));
    }
  }

  template <typename L1, typename L2, typename L3>
  result_type operator()(const L1& l1, const L2& l2, const L3& l3) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      return new Lazy_construct_rep_3<AC, EC, To_interval<ET>, L1,L2,L3>(ac, ec, l1,l2,l3);
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return new Lazy_construct_rep_0<AT,ET,To_interval<ET> >(ec(CGAL::exact(l1), exact(l2), exact(l3)));
    }
  }
};


template <typename LK>
Object
make_lazy(const Object& eto)
{
  typedef typename LK::AK AK;
  typedef typename LK::EK EK;
  typedef typename LK::E2A E2A;

  if (eto.is_empty())
    return Object();

  if(const typename EK::Point_2* ptr = object_cast<typename EK::Point_2>(&eto)){
    return make_object(typename LK::Point_2(new Lazy_construct_rep_0<typename AK::Point_2, typename EK::Point_2, E2A>(*ptr)));
  } else if(const typename EK::Segment_2* ptr = object_cast<typename EK::Segment_2>(&eto)){
    return make_object(typename LK::Segment_2(new Lazy_construct_rep_0<typename AK::Segment_2, typename EK::Segment_2, E2A>(*ptr)));
  } else if(const typename EK::Ray_2* ptr = object_cast<typename EK::Ray_2>(&eto)){
    return make_object(typename LK::Ray_2(new Lazy_construct_rep_0<typename AK::Ray_2, typename EK::Ray_2, E2A>(*ptr)));
  } else if(const typename EK::Line_2* ptr = object_cast<typename EK::Line_2>(&eto)){
    return make_object(typename LK::Line_2(new Lazy_construct_rep_0<typename AK::Line_2, typename EK::Line_2, E2A>(*ptr)));
  } else if(const typename EK::Triangle_2* ptr = object_cast<typename EK::Triangle_2>(&eto)){
    return make_object(typename LK::Triangle_2(new Lazy_construct_rep_0<typename AK::Triangle_2, typename EK::Triangle_2, E2A>(*ptr)));
  } else if(const typename EK::Iso_rectangle_2* ptr = object_cast<typename EK::Iso_rectangle_2>(&eto)){
    return make_object(typename LK::Iso_rectangle_2(new Lazy_construct_rep_0<typename AK::Iso_rectangle_2, typename EK::Iso_rectangle_2, E2A>(*ptr)));
  } else if(const typename EK::Circle_2* ptr = object_cast<typename EK::Circle_2>(&eto)){
    return make_object(typename LK::Circle_2(new Lazy_construct_rep_0<typename AK::Circle_2, typename EK::Circle_2, E2A>(*ptr)));
  } else{
    std::cerr << "object_cast inside Lazy_construction_rep::operator() failed. It needs more else if's (#2)" << std::endl;
    std::cerr << "dynamic type of the Object : " << eto.type().name() << std::endl;
  }            
  return Object();
}


// This functor selects the i'th element in a vector of Object's 
// and casts it to what is in the Object

template <typename T2>
struct Ith {
  typedef T2 result_type;
  
  // We keep a Sign member object
  // for future utilisation , in case
  // we have pairs of 2 T2 objects e.g.
  // for a numeric_point vector returned
  // from a construction of a possible
  // lazy algebraic kernel
  
  int i;
  Sign sgn;
  
  Ith(int i_)
    : i(i_)
  {sgn=NEGATIVE;}
  
  Ith(int i_, bool b_)
    : i(i_)
  { sgn= (b_) ? POSITIVE : ZERO;}  
  
  const T2&
  operator()(const std::vector<Object>& v) const
  {
    if(sgn==NEGATIVE)
    return *object_cast<T2>(&v[i]);
    
    typedef std::pair<T2,unsigned int >         Pair_type_1;
    typedef std::pair<T2,std::pair<bool,bool> > Pair_type_2;
    
    if(const Pair_type_1 *p1 = object_cast<Pair_type_1>(&v[i]))
    	return p1->first;
    else if(const Pair_type_2 *p2 = object_cast<Pair_type_2>(&v[i]))
        return p2->first;
    
    std::cout<<" Unexpected encapsulated type "<<std::endl;
    abort();    	    
  }
};




template <typename LK, typename AC, typename EC>
struct Lazy_cartesian_const_iterator_2 {


  typedef typename LK::AK AK;
  typedef typename LK::EK EK;
  typedef typename LK::Cartesian_const_iterator_2 result_type;
  AC ac;
  EC ec;

public:

  template < typename L1>
  result_type
  operator()(const L1& l1) const
  {
    return result_type(&l1);
  }

  template < typename L1>
  result_type
  operator()(const L1& l1, int i) const
  {
    return result_type(&l1,i);
  }

};

// This is the magic functor for functors that write their result in a  reference argument
// In a first version we assume that the references are of type Lazy<Something>,
// and that the result type is void
//

template <typename LK, typename AK, typename EK, typename AC, typename EC, typename EFT, typename E2A>
struct Lazy_functor_2_1 {
  static const bool Protection  = true;
  typedef void result_type;
  AC ac;
  EC ec;

public:

  template <typename L1, typename L2, typename R1>
  void
  operator()(const L1& l1, const L2& l2, R1& r1) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      // we suppose that R1 is a Lazy<Something>
      r1 = R1(new Lazy_construct_rep_2_1<AC, EC, E2A, L1, L2, R1>(ac, ec, l1, l2));
    } catch(Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      typename R1::ET et;
      ec(CGAL::exact(l1), CGAL::exact(l2), et);
      r1 = R1(new Lazy_construct_rep_0<typename R1::AT,typename R1::ET,E2A>(et));
    }
  }
};


template <typename T>
 struct First {
   typedef typename T::first_type result_type;

   const typename T::first_type&
   operator()(const T& p) const
   {
     return p.first;
   }
 };

 template <typename T>
 struct Second {
   typedef typename T::second_type result_type;

   const typename T::second_type&
   operator()(const T& p) const
   {
     return p.second;
   }
 };

// This is the magic functor for functors that write their result in a reference argument
// In a first version we assume that the references are of type Lazy<Something>,
// and that the result type is void
//

//template <typename LK, typename AK, typename EK, typename AC, typename EC, typename EFT, typename E2A>
template <typename LK, typename AC, typename EC>
struct Lazy_functor_2_2 {
  static const bool Protection  = true;
  typedef void result_type;
  typedef typename LK::AK AK;
  typedef typename LK::EK EK;
  typedef typename EK::FT EFT;
  typedef typename LK::E2A E2A;
  AC ac;
  EC ec;

public:

  template <typename L1, typename L2, typename R1, typename R2>
  void
  operator()(const L1& l1, const L2& l2, R1& r1, R2& r2) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      typedef Lazy<std::pair<typename R1::AT, typename R2::AT> , std::pair<typename R1::ET, typename R2::ET> , EFT, E2A> Lazy_pair;
      Lazy_pair lv(new Lazy_construct_rep_2_2<AC, EC, E2A, L1, L2, R1, R2>(ac, ec, l1, l2));
      // lv->approx() is a std::pair<R1::AT, R2::AT>;
      r1 = R1(new Lazy_construct_rep_1<First<std::pair<typename R1::AT, typename R2::AT> >, First<std::pair<typename R1::ET, typename R2::ET> >, E2A, Lazy_pair>(First<std::pair<typename R1::AT, typename R2::AT> >(), First<std::pair<typename R1::ET, typename R2::ET> >(), lv));
      r2 = R2(new Lazy_construct_rep_1<Second<std::pair<typename R1::AT, typename R2::AT> >, Second<std::pair<typename R1::ET, typename R2::ET> >, E2A, Lazy_pair>(Second<std::pair<typename R1::AT, typename R2::AT> >(), Second<std::pair<typename R1::ET, typename R2::ET> >(), lv));
    } catch(Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      typename R1::ET et1, et2;
      ec(CGAL::exact(l1), CGAL::exact(l2), et1, et2);
      r1 = R1(new Lazy_construct_rep_0<typename R1::AT,typename R1::ET,E2A>(et1));
      r2 = R2(new Lazy_construct_rep_0<typename R2::AT,typename R2::ET,E2A>(et2));
    }
  }
};



// This is the magic functor for functors that write their result as Objects into an output iterator

template <typename LK, typename AC, typename EC>
struct Lazy_intersect_with_iterators {

  static const bool Protection = true;
  typedef typename LK::AK AK;
  typedef typename LK::EK EK;
  typedef typename EK::FT EFT;
  typedef typename LK::E2A E2A;
  typedef void result_type;
  typedef Lazy<Object, Object, EFT, E2A> Lazy_object;
  typedef Lazy<std::vector<Object>, std::vector<Object>, EFT, E2A> Lazy_vector;
  AC ac;
  EC ec;

public:

  // In the example we intersect two Lazy<Segment>s
  // and write into a back_inserter(list<Object([Lazy<Point>,Lazy<Segment>]) >)
  template <typename L1, typename L2, typename OutputIterator>
  OutputIterator
  operator()(const L1& l1, const L2& l2, OutputIterator it) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      Lazy_vector lv(new Lazy_construct_rep_with_vector_2<AC, EC, E2A, L1, L2>(ac, ec, l1, l2));
      // lv.approx() is a std::vector<Object([AK::Point_2,AK::Segment_2])>
      // that is, when we get here we have constructed all approximate results
      for(unsigned int i = 0; i < lv.approx().size(); i++){
	if(object_cast<typename AK::Point_2>(& (lv.approx()[i]))){
	  *it = make_object(typename LK::Point_2(new Lazy_construct_rep_1<Ith<typename AK::Point_2>, Ith<typename EK::Point_2>, E2A, Lazy_vector>(Ith<typename AK::Point_2>(i), Ith<typename EK::Point_2>(i), lv)));
	  ++it;
	} else if(object_cast<typename AK::Segment_2>(& (lv.approx()[i]))){
	  *it = make_object(typename LK::Segment_2(new Lazy_construct_rep_1<Ith<typename AK::Segment_2>, Ith<typename EK::Segment_2>, E2A, Lazy_vector>(Ith<typename AK::Segment_2>(i), Ith<typename EK::Segment_2>(i), lv)));
	  ++it;
	} else if(object_cast<typename AK::Ray_2>(& (lv.approx()[i]))){
	  *it = make_object(typename LK::Ray_2(new Lazy_construct_rep_1<Ith<typename AK::Ray_2>, Ith<typename EK::Ray_2>, E2A, Lazy_vector>(Ith<typename AK::Ray_2>(i), Ith<typename EK::Ray_2>(i), lv)));
	  ++it;
	} else if(object_cast<typename AK::Line_2>(& (lv.approx()[i]))){
	  *it = make_object(typename LK::Line_2(new Lazy_construct_rep_1<Ith<typename AK::Line_2>, Ith<typename EK::Line_2>, E2A, Lazy_vector>(Ith<typename AK::Line_2>(i), Ith<typename EK::Line_2>(i), lv)));
	  ++it;
	} else if(object_cast<typename AK::Triangle_2>(& (lv.approx()[i]))){
	  *it = make_object(typename LK::Triangle_2(new Lazy_construct_rep_1<Ith<typename AK::Triangle_2>, Ith<typename EK::Triangle_2>, E2A, Lazy_vector>(Ith<typename AK::Triangle_2>(i), Ith<typename EK::Triangle_2>(i), lv)));
	  ++it;
	} else if(object_cast<typename AK::Iso_rectangle_2>(& (lv.approx()[i]))){
	  *it = make_object(typename LK::Iso_rectangle_2(new Lazy_construct_rep_1<Ith<typename AK::Iso_rectangle_2>, Ith<typename EK::Iso_rectangle_2>, E2A, Lazy_vector>(Ith<typename AK::Iso_rectangle_2>(i), Ith<typename EK::Iso_rectangle_2>(i), lv)));
	  ++it;
	} else if(object_cast<typename AK::Circle_2>(& (lv.approx()[i]))){
	  *it = make_object(typename LK::Circle_2(new Lazy_construct_rep_1<Ith<typename AK::Circle_2>, Ith<typename EK::Circle_2>, E2A, Lazy_vector>(Ith<typename AK::Circle_2>(i), Ith<typename EK::Circle_2>(i), lv)));
	  ++it;
	} else{
	  std::cerr << "we need  more casts" << std::endl;
	}
      }
      
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      // TODO: Instead of using a vector, write an iterator adapter
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      std::vector<Object> exact_objects;
      ec(CGAL::exact(l1), CGAL::exact(l2), std::back_inserter(exact_objects));
      for (std::vector<Object>::const_iterator oit = exact_objects.begin();
	   oit != exact_objects.end();
	   ++oit){
	*it++ = make_lazy<LK>(*oit);
      }
    }
    return it;
  }
};



template <typename T>
struct Object_cast {
  typedef T result_type;

  const T&
  operator()(const Object& o) const
  {
    return *object_cast<T>(&o);
  }
};

// The following functor returns an Object with a Lazy<Something> inside
// As the nested kernels return Objects of AK::Something and EK::Something
// we have to unwrap them from the Object, and wrap them in a Lazy<Something>
//
// TODO: write operators for other than two arguments. For the current kernel we only need two for Interscet_2

template <typename LK, typename AC, typename EC>
struct Lazy_construction_object {

  static const bool Protection = true;
  typedef typename LK::AK AK;
  typedef typename LK::EK EK;
  typedef typename EK::FT EFT;
  typedef typename LK::E2A E2A;
  typedef typename AC::result_type AT;
  typedef typename EC::result_type ET;
  typedef Object result_type;

  typedef Lazy<Object, Object, EFT, E2A> Lazy_object;
  AC ac;
  EC ec;

public:

  template <typename L1, typename L2>
  result_type
  operator()(const L1& l1, const L2& l2) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      Lazy_object lo(new Lazy_construct_rep_2<AC, EC, E2A, L1, L2>(ac, ec, l1, l2));
 
      if(lo.approx().is_empty())
        return Object();
      if(object_cast<typename AK::Point_2>(& (lo.approx()))){
	typedef Lazy_construct_rep_1<Object_cast<typename AK::Point_2>, Object_cast<typename EK::Point_2>, E2A, Lazy_object> Lcr;
	Lcr * lcr = new Lcr(Object_cast<typename AK::Point_2>(), Object_cast<typename EK::Point_2>(), lo); 
	return make_object(typename LK::Point_2(lcr));
      } else if(object_cast<typename AK::Segment_2>(& (lo.approx()))){
	typedef Lazy_construct_rep_1<Object_cast<typename AK::Segment_2>, Object_cast<typename EK::Segment_2>, E2A, Lazy_object> Lcr;
	Lcr * lcr = new Lcr(Object_cast<typename AK::Segment_2>(), Object_cast<typename EK::Segment_2>(), lo); 
	return make_object(typename LK::Segment_2(lcr));
      } else if(object_cast<typename AK::Ray_2>(& (lo.approx()))){
	typedef Lazy_construct_rep_1<Object_cast<typename AK::Ray_2>, Object_cast<typename EK::Ray_2>, E2A, Lazy_object> Lcr;
	Lcr * lcr = new Lcr(Object_cast<typename AK::Ray_2>(), Object_cast<typename EK::Ray_2>(), lo); 
	return make_object(typename LK::Ray_2(lcr));
      } else if(object_cast<typename AK::Line_2>(& (lo.approx()))){
	typedef Lazy_construct_rep_1<Object_cast<typename AK::Line_2>, Object_cast<typename EK::Line_2>, E2A, Lazy_object> Lcr;
	Lcr * lcr = new Lcr(Object_cast<typename AK::Line_2>(), Object_cast<typename EK::Line_2>(), lo); 
	return make_object(typename LK::Line_2(lcr));
      }  else if(object_cast<typename AK::Circle_2>(& (lo.approx()))){
	typedef Lazy_construct_rep_1<Object_cast<typename AK::Circle_2>, Object_cast<typename EK::Circle_2>, E2A, Lazy_object> Lcr;
	Lcr * lcr = new Lcr(Object_cast<typename AK::Circle_2>(), Object_cast<typename EK::Circle_2>(), lo); 
	return make_object(typename LK::Circle_2(lcr));
      } else if(object_cast<typename AK::Iso_rectangle_2>(& (lo.approx()))){
	typedef Lazy_construct_rep_1<Object_cast<typename AK::Iso_rectangle_2>, Object_cast<typename EK::Iso_rectangle_2>, E2A, Lazy_object> Lcr;
	Lcr * lcr = new Lcr(Object_cast<typename AK::Iso_rectangle_2>(), Object_cast<typename EK::Iso_rectangle_2>(), lo); 
	return make_object(typename LK::Iso_rectangle_2(lcr));
      }  else if(object_cast<typename AK::Triangle_2>(& (lo.approx()))){
	typedef Lazy_construct_rep_1<Object_cast<typename AK::Triangle_2>, Object_cast<typename EK::Triangle_2>, E2A, Lazy_object> Lcr;
	Lcr * lcr = new Lcr(Object_cast<typename AK::Triangle_2>(), Object_cast<typename EK::Triangle_2>(), lo); 
	return make_object(typename LK::Triangle_2(lcr));
      }   else {
	std::cerr << "object_cast inside Lazy_construction_rep::operator() failed. It needs more else if's (#1)" << std::endl;
        std::cerr << "dynamic type of the Object : " << lo.approx().type().name() << std::endl;
      }
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      ET eto = ec(CGAL::exact(l1), CGAL::exact(l2));
      return make_lazy<LK>(eto);
    }
    return Object();
  }
  

};



//____________________________________________________________
// The magic functor that has Lazy<Something> as result type

template <typename LK, typename AC, typename EC>
struct Lazy_construction {

  static const bool Protection  = true;

  typedef typename LK::AK AK;
  typedef typename LK::EK EK;
  typedef typename EK::FT EFT;
  typedef typename LK::E2A E2A;
  typedef typename AC::result_type AT;
  typedef typename EC::result_type ET;
  typedef Lazy<AT, ET, EFT, E2A> Handle;
  typedef typename Type_mapper<AT,AK,LK>::type result_type;

  AC ac;
  EC ec;

public:

  result_type
  operator()() const
  {
    return Handle(new Lazy_construct_rep_0<AT,ET,E2A>());
  }


  template <typename L1>
  result_type
  operator()(const L1& l1) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      return  Handle(new Lazy_construct_rep_1<AC, EC, E2A, L1>(ac, ec, l1));
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return Handle(new Lazy_construct_rep_0<AT,ET,E2A>(ec(CGAL::exact(l1))));
    }
  }

  template <typename L1, typename L2>
  result_type
  operator()(const L1& l1, const L2& l2) const
  {
    try {
       CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      return Handle(new Lazy_construct_rep_2<AC, EC, E2A, L1, L2>(ac, ec, l1, l2));
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return Handle(new Lazy_construct_rep_0<AT,ET,E2A>(ec(CGAL::exact(l1), CGAL::exact(l2))));
    }
  }
  

  template <typename L1, typename L2, typename L3>
  result_type
  operator()(const L1& l1, const L2& l2, const L3& l3) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
      return Handle(new Lazy_construct_rep_3<AC, EC, E2A, L1, L2, L3>(ac, ec, l1, l2, l3));
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return Handle(new Lazy_construct_rep_0<AT,ET,E2A>(ec(CGAL::exact(l1), CGAL::exact(l2), CGAL::exact(l3))));
    }
  }

  template <typename L1, typename L2, typename L3, typename L4>
  result_type
  operator()(const L1& l1, const L2& l2, const L3& l3, const L4& l4) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
    return Handle(new Lazy_construct_rep_4<AC, EC, E2A, L1, L2, L3, L4>(ac, ec, l1, l2, l3, l4));
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return Handle(new Lazy_construct_rep_0<AT,ET,E2A>(ec(CGAL::exact(l1), CGAL::exact(l2), CGAL::exact(l3), CGAL::exact(l4))));
    }
  }

  template <typename L1, typename L2, typename L3, typename L4, typename L5>
  result_type
  operator()(const L1& l1, const L2& l2, const L3& l3, const L4& l4, const L5& l5) const
  {
    try {
      CGAL_PROFILER(std::string("calls to : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<Protection> P;
    return Handle(new Lazy_construct_rep_5<AC, EC, E2A, L1, L2, L3, L4, L5>(ac, ec, l1, l2, l3, l4, l5));
    } catch (Interval_nt_advanced::unsafe_comparison) {
      CGAL_PROFILER(std::string("failures of : ") + std::string(CGAL_PRETTY_FUNCTION));
      Protect_FPU_rounding<!Protection> P(CGAL_FE_TONEAREST);
      return Handle(new Lazy_construct_rep_0<AT,ET,E2A>(ec(CGAL::exact(l1), CGAL::exact(l2), CGAL::exact(l3), CGAL::exact(l4), CGAL::exact(l5))));
    }
  }
};





CGAL_END_NAMESPACE


#endif // CGAL_LAZY_H