exercise-5-8.hpp

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// ===-- chapter-5/exercise-5-8.hpp ----------------------- -*- C++ -*- --=== //
#ifndef EXERCISE_5_8
#define EXERCISE_5_8
 
#include <boost/static_assert.hpp>
 
#include <boost/mpl/advance.hpp>
#include <boost/mpl/begin_end.hpp>
#include <boost/mpl/deref.hpp>
#include <boost/mpl/iterator_tags.hpp>
#include <boost/mpl/next_prior.hpp>
 
 
namespace exercise_5_8 {
 
struct fibonacci_series_tag { };
 
template <size_t N, size_t LastN>
struct fibonacci_series_iterator
{
    typedef boost::mpl::forward_iterator_tag category;
};
 
struct fibonacci_series
{
    typedef fibonacci_series_tag tag;
};
 
} // namespace exercise_5_8
 
 
namespace boost {
namespace mpl {
 
 
template <>
struct begin_impl<exercise_5_8::fibonacci_series_tag>
{
    template <typename S>
    struct apply
    {
        typedef exercise_5_8::fibonacci_series_iterator<0, 1> type;
    };
};
 
template <size_t N, size_t LastN>
struct next< exercise_5_8::fibonacci_series_iterator<N,LastN> >
{
    typedef exercise_5_8::fibonacci_series_iterator<N+LastN, N> type;
};
 
template <size_t N, size_t LastN>
struct deref< exercise_5_8::fibonacci_series_iterator<N,LastN> >
    : boost::mpl::int_<N> { };
 
 
} // namespace mpl
} // namespace boost
 
#endif // EXERCISE_5_8