ceph/src/boost/boost/mp11/detail/mp_fold.hpp

   1 #ifndef BOOST_MP11_DETAIL_MP_FOLD_HPP_INCLUDED
   2 #define BOOST_MP11_DETAIL_MP_FOLD_HPP_INCLUDED
   3
   4 //  Copyright 2015-2017 Peter Dimov.
   5 //
   6 //  Distributed under the Boost Software License, Version 1.0.
   7 //
   8 //  See accompanying file LICENSE_1_0.txt or copy at
   9 //  http://www.boost.org/LICENSE_1_0.txt
  10
  11 #include <boost/config.hpp>
  12 #include <boost/detail/workaround.hpp>
  13
  14 namespace boost
  15 {
  16 namespace mp11
  17 {
  18
  19 // mp_fold<L, V, F>
  20 namespace detail
  21 {
  22
  23 template<class L, class V, template<class...> class F> struct mp_fold_impl
  24 {
  25 // An error "no type named 'type'" here means that the first argument to mp_fold is not a list
  26 };
  27
  28 #if defined( BOOST_MSVC ) && BOOST_WORKAROUND( BOOST_MSVC, <= 1800 )
  29
  30 template<template<class...> class L, class... T, class V, template<class...> class F> struct mp_fold_impl<L<T...>, V, F>
  31 {
  32     static_assert( sizeof...(T) == 0, "T... must be empty" );
  33     using type = V;
  34 };
  35
  36 #else
  37
  38 template<template<class...> class L, class V, template<class...> class F> struct mp_fold_impl<L<>, V, F>
  39 {
  40     using type = V;
  41 };
  42
  43 #endif
  44
  45 template<template<class...> class L, class T1, class... T, class V, template<class...> class F> struct mp_fold_impl<L<T1, T...>, V, F>
  46 {
  47     using type = typename mp_fold_impl<L<T...>, F<V, T1>, F>::type;
  48 };
  49
  50 template<template<class...> class L, class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class T9, class T10, class... T, class V, template<class...> class F> struct mp_fold_impl<L<T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T...>, V, F>
  51 {
  52     using type = typename mp_fold_impl<L<T...>, F<F<F<F<F<F<F<F<F<F<V, T1>, T2>, T3>, T4>, T5>, T6>, T7>, T8>, T9>, T10>, F>::type;
  53 };
  54
  55 } // namespace detail
  56
  57 template<class L, class V, template<class...> class F> using mp_fold = typename detail::mp_fold_impl<L, V, F>::type;
  58 template<class L, class V, class Q> using mp_fold_q = mp_fold<L, V, Q::template fn>;
  59
  60 } // namespace mp11
  61 } // namespace boost
  62
  63 #endif // #ifndef BOOST_MP11_DETAIL_MP_FOLD_HPP_INCLUDED