// Copyright (C) 2004 Peder Holt
// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_TYPEOF_VECTOR_CTC_HPP_INCLUDED
#define BOOST_TYPEOF_VECTOR_CTC_HPP_INCLUDED

#include <boost/mpl/push_back.hpp>
#include <boost/mpl/begin_end.hpp>
#include <boost/mpl/deref.hpp>
#include <boost/mpl/next.hpp>

namespace boost { namespace mpl {

#define CTC_INDEX() sizeof(boost::mpl::ctc_index((boost::mpl::aux::ctc_counter<64>*)NULL))
#define CTC_VALUE(index,pos) sizeof(boost::mpl::ctc_value((boost::mpl::aux::ctc_counter<index>*)NULL,(boost::mpl::aux::ctc_size<pos>*)NULL))

namespace aux {
  template<unsigned N>
  struct ctc_size {
     BOOST_STATIC_CONSTANT(unsigned,value=N);
     typedef char type[value];
  };

  template<int N> struct ctc_counter : ctc_counter<N-1> {};
  template<> struct ctc_counter<0> {};

  struct ctc_vector_tag {};

  template<unsigned Index,unsigned Pos>
  struct ctc_vector_impl {
     typedef ctc_vector_tag tag;
     BOOST_STATIC_CONSTANT(unsigned,index=Index);
     BOOST_STATIC_CONSTANT(unsigned,pos=Pos);
  };
}

aux::ctc_size<1>::type &ctc_index(...);

template<unsigned Index>
struct ctc_vector : aux::ctc_vector_impl<Index,1>
{
  BOOST_STATIC_CONSTANT(unsigned,value=Index);
  BOOST_STATIC_CONSTANT(unsigned,next=value+1);
  typedef aux::ctc_vector_tag tag;
  friend typename aux::ctc_size<next>::type &ctc_index(aux::ctc_counter<value>*);
};

template<unsigned Index,unsigned Pos=1>
struct ctc_iterator {
  BOOST_STATIC_CONSTANT(unsigned,value=CTC_VALUE(Index,Pos));
  typedef ctc_iterator<Index,Pos+1> next;
  typedef mpl::size_t<value> type;
};

template<>
struct push_back_impl< aux::ctc_vector_tag >
{
   template< typename Vector, typename T > struct apply
   {
       BOOST_STATIC_CONSTANT(unsigned,index=Vector::index);
       BOOST_STATIC_CONSTANT(unsigned,pos=Vector::pos);

       friend typename aux::ctc_size<T::value>::type &ctc_value(aux::ctc_counter<index>*,aux::ctc_size<pos>*);
       typedef aux::ctc_vector_impl<index,pos+1> type;
   };
};

template<>
struct begin_impl< aux::ctc_vector_tag >
{
   template< typename Vector > struct apply
   {
       BOOST_STATIC_CONSTANT(unsigned,index=Vector::index);
       typedef ctc_iterator<index,1> type;
   };
};

}}

#endif