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

   1 #ifndef BOOST_MP11_DETAIL_MP_MAP_FIND_HPP_INCLUDED
   2 #define BOOST_MP11_DETAIL_MP_MAP_FIND_HPP_INCLUDED
   3
   4 //  Copyright 2015 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/mp11/utility.hpp>
  12 #include <boost/mp11/detail/config.hpp>
  13
  14 #if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1930 )
  15
  16 // not exactly good practice, but...
  17 namespace std
  18 {
  19     template<class... _Types> class tuple;
  20 }
  21
  22 #endif
  23
  24 namespace boost
  25 {
  26 namespace mp11
  27 {
  28
  29 // mp_map_find
  30 namespace detail
  31 {
  32
  33 #if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1930 )
  34
  35 template<class T> using mpmf_wrap = mp_identity<T>;
  36 template<class T> using mpmf_unwrap = typename T::type;
  37
  38 #else
  39
  40 template<class... T> struct mpmf_tuple {};
  41
  42 template<class T> struct mpmf_wrap_impl
  43 {
  44     using type = mp_identity<T>;
  45 };
  46
  47 template<class... T> struct mpmf_wrap_impl< std::tuple<T...> >
  48 {
  49     using type = mp_identity< mpmf_tuple<T...> >;
  50 };
  51
  52 template<class T> using mpmf_wrap = typename mpmf_wrap_impl<T>::type;
  53
  54 template<class T> struct mpmf_unwrap_impl
  55 {
  56     using type = typename T::type;
  57 };
  58
  59 template<class... T> struct mpmf_unwrap_impl< mp_identity< mpmf_tuple<T...> > >
  60 {
  61     using type = std::tuple<T...>;
  62 };
  63
  64 template<class T> using mpmf_unwrap = typename mpmf_unwrap_impl<T>::type;
  65
  66 #endif // #if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1930 )
  67
  68 template<class M, class K> struct mp_map_find_impl;
  69
  70 template<template<class...> class M, class... T, class K> struct mp_map_find_impl<M<T...>, K>
  71 {
  72     using U = mp_inherit<mpmf_wrap<T>...>;
  73
  74     template<template<class...> class L, class... U> static mp_identity<L<K, U...>> f( mp_identity<L<K, U...>>* );
  75     static mp_identity<void> f( ... );
  76
  77     using type = mpmf_unwrap< decltype( f((U*)0) ) >;
  78 };
  79
  80 } // namespace detail
  81
  82 template<class M, class K> using mp_map_find = typename detail::mp_map_find_impl<M, K>::type;
  83
  84 } // namespace mp11
  85 } // namespace boost
  86
  87 #endif // #ifndef BOOST_MP11_DETAIL_MP_MAP_FIND_HPP_INCLUDED