variadic_to_vmpl.hpp

/*
 * to_variadic.hpp
 *
 * Set of classes to convert from a boost::mpl::vector into an S variadic template
 * class appling a metafunction F on each element
 *
 * boost::mpl::vector<T,A,B> is converted into
 *
 * S<F<T>,F<A>,F<B>>
 *
 * \see to_variadic
 *
 *  Created on: Aug 27, 2014
 *      Author: Pietro Incardona
 */

#ifndef V_TRANSFORM_HPP
#define V_TRANSFORM_HPP

#include <boost/fusion/container/vector.hpp>
#include <boost/mpl/int.hpp>
#include <boost/mpl/reverse.hpp>
#include <boost/mpl/vector.hpp>
#include <boost/mpl/range_c.hpp>
#include <boost/fusion/sequence/intrinsic/at_c.hpp>
#include <boost/fusion/include/at_c.hpp>
#include <boost/mpl/accumulate.hpp>


template<typename F,typename L>
struct exit_impl : boost::mpl::equal_to<typename boost::mpl::distance<F,L>::type,boost::mpl::int_<0>>
{};

template<template<typename> class H, typename F,typename L, bool exit,typename ...Args>
struct v_transform_impl
{
   typedef typename boost::mpl::deref<F>::type front_;

   typedef typename boost::mpl::next<F>::type next_;

   typedef typename exit_impl<next_,L>::type exit_;

   typedef typename v_transform_impl<H,next_,L,exit_::value,typename H<front_>::type,Args...>::type type;
};


template<template<typename> class H,typename F,typename L,typename ...Args>
struct v_transform_impl<H,F,L,true,Args...>
{
   typedef boost::fusion::vector<Args...> type;
};

template<typename Seq>
struct seq_traits_impl
{
   typedef typename boost::mpl::begin<Seq>::type first_;

   typedef typename boost::mpl::end<Seq>::type last_;

   typedef typename exit_impl<first_,last_>::type exit_;
};

template<template<typename> class H,typename L>
struct v_transform
{
    typedef typename boost::mpl::reverse<L>::type reversed_;

    typedef typename seq_traits_impl<reversed_>::first_ first;

    typedef typename seq_traits_impl<reversed_>::last_ last;

    typedef typename exit_impl<first,last>::type exit_;

    typedef typename v_transform_impl<H,first,last,exit_::value >::type type;
};




template<template<typename,typename> class H, typename arg0, typename F,typename L, bool exit,typename ...Args>
struct v_transform_two_impl
{
   typedef typename boost::mpl::deref<F>::type front_;

   typedef typename boost::mpl::next<F>::type next_;

   typedef typename exit_impl<next_,L>::type exit_;

   typedef typename v_transform_two_impl<H,arg0,next_,L,exit_::value,typename H<arg0,front_>::type,Args...>::type type;
};


template<template<typename,typename> class H,typename arg0, typename F,typename L,typename ...Args>
struct v_transform_two_impl<H,arg0,F,L,true,Args...>
{
   typedef boost::fusion::vector<Args...> type;
};

template<template<typename,typename> class H,typename arg0, typename L>
struct v_transform_two
{
    typedef typename boost::mpl::reverse<L>::type reversed_;

    typedef typename seq_traits_impl<reversed_>::first_ first;

    typedef typename seq_traits_impl<reversed_>::last_ last;

    typedef typename exit_impl<first,last>::type exit_;

    typedef typename v_transform_two_impl<H,arg0,first,last,exit_::value >::type type;
};


template <int a, int... id>
struct to_boost_vmpl_impl
{
    typedef typename boost::mpl::push_front<typename to_boost_vmpl_impl<id...>::type,boost::mpl::int_<a>>::type type;
};

template <int a>
struct to_boost_vmpl_impl<a>
{
    typedef boost::mpl::vector<boost::mpl::int_<a>> type;
};

template <int... id>
struct to_boost_vmpl
{
    typedef typename to_boost_vmpl_impl<id...>::type type;
};

template <>
struct to_boost_vmpl<>
{
    typedef typename boost::mpl::vector<>::type type;
};


template <unsigned T1, unsigned int ...T>
struct first_variadic
{
    typedef boost::mpl::int_<T1> type;
};

template <unsigned int T1, unsigned int ...T>
struct last_variadic
{
    typedef typename last_variadic<T...>::type type;
};

template <unsigned int T1>
struct last_variadic<T1>
{
    typedef boost::mpl::int_<T1> type;
};

template <unsigned int ... prp>
struct is_contiguos
{
    typedef boost::mpl::range_c<int,first_variadic<prp...>::type::value,last_variadic<prp...>::type::value + 1> rangec;

    typedef typename boost::mpl::size<rangec>::type size_range;

    typedef typename boost::mpl::accumulate<rangec,
                                   boost::mpl::int_<0>,
                                   boost::mpl::plus<typename boost::mpl::placeholders::_2,
                                                    typename boost::mpl::placeholders::_1>
                                  >::type accum;

    typedef typename to_boost_vmpl<prp...>::type prop_vector;

    typedef typename boost::mpl::accumulate<prop_vector,
                                   boost::mpl::int_<0>,
                                   boost::mpl::plus<typename boost::mpl::placeholders::_2,
                                                    typename boost::mpl::placeholders::_1>
                                  >::type accum_prp;

    typedef boost::mpl::bool_<sizeof...(prp) == size_range::value && accum_prp::value == accum::value > type;
};

#endif