ceph/src/boost/boost/mp11/utility.hpp

   1 #ifndef BOOST_MP11_UTILITY_HPP_INCLUDED
   2 #define BOOST_MP11_UTILITY_HPP_INCLUDED
   3
   4 // Copyright 2015-2020 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/integral.hpp>
  12 #include <boost/mp11/detail/mp_list.hpp>
  13 #include <boost/mp11/detail/mp_fold.hpp>
  14 #include <boost/mp11/detail/config.hpp>
  15
  16 namespace boost
  17 {
  18 namespace mp11
  19 {
  20
  21 // mp_identity
  22 template<class T> struct mp_identity
  23 {
  24     using type = T;
  25 };
  26
  27 // mp_identity_t
  28 template<class T> using mp_identity_t = typename mp_identity<T>::type;
  29
  30 // mp_inherit
  31 template<class... T> struct mp_inherit: T... {};
  32
  33 // mp_if, mp_if_c
  34 namespace detail
  35 {
  36
  37 template<bool C, class T, class... E> struct mp_if_c_impl
  38 {
  39 };
  40
  41 template<class T, class... E> struct mp_if_c_impl<true, T, E...>
  42 {
  43     using type = T;
  44 };
  45
  46 template<class T, class E> struct mp_if_c_impl<false, T, E>
  47 {
  48     using type = E;
  49 };
  50
  51 } // namespace detail
  52
  53 template<bool C, class T, class... E> using mp_if_c = typename detail::mp_if_c_impl<C, T, E...>::type;
  54 template<class C, class T, class... E> using mp_if = typename detail::mp_if_c_impl<static_cast<bool>(C::value), T, E...>::type;
  55
  56 // mp_valid
  57
  58 #if BOOST_MP11_WORKAROUND( BOOST_MP11_INTEL, != 0 ) // tested at 1800
  59
  60 // contributed by Roland Schulz in https://github.com/boostorg/mp11/issues/17
  61
  62 namespace detail
  63 {
  64
  65 template<class...> using void_t = void;
  66
  67 template<class, template<class...> class F, class... T>
  68 struct mp_valid_impl: mp_false {};
  69
  70 template<template<class...> class F, class... T>
  71 struct mp_valid_impl<void_t<F<T...>>, F, T...>: mp_true {};
  72
  73 } // namespace detail
  74
  75 template<template<class...> class F, class... T> using mp_valid = typename detail::mp_valid_impl<void, F, T...>;
  76
  77 #else
  78
  79 // implementation by Bruno Dutra (by the name is_evaluable)
  80 namespace detail
  81 {
  82
  83 template<template<class...> class F, class... T> struct mp_valid_impl
  84 {
  85     template<template<class...> class G, class = G<T...>> static mp_true check(int);
  86     template<template<class...> class> static mp_false check(...);
  87
  88     using type = decltype(check<F>(0));
  89 };
  90
  91 } // namespace detail
  92
  93 template<template<class...> class F, class... T> using mp_valid = typename detail::mp_valid_impl<F, T...>::type;
  94
  95 #endif
  96
  97 template<class Q, class... T> using mp_valid_q = mp_valid<Q::template fn, T...>;
  98
  99 // mp_defer
 100 namespace detail
 101 {
 102
 103 template<template<class...> class F, class... T> struct mp_defer_impl
 104 {
 105     using type = F<T...>;
 106 };
 107
 108 struct mp_no_type
 109 {
 110 };
 111
 112 #if BOOST_MP11_WORKAROUND( BOOST_MP11_CUDA, >= 9000000 && BOOST_MP11_CUDA < 10000000 )
 113
 114 template<template<class...> class F, class... T> struct mp_defer_cuda_workaround
 115 {
 116     using type = mp_if<mp_valid<F, T...>, detail::mp_defer_impl<F, T...>, detail::mp_no_type>;
 117 };
 118
 119 #endif
 120
 121 } // namespace detail
 122
 123 #if BOOST_MP11_WORKAROUND( BOOST_MP11_CUDA, >= 9000000 && BOOST_MP11_CUDA < 10000000 )
 124
 125 template<template<class...> class F, class... T> using mp_defer = typename detail::mp_defer_cuda_workaround< F, T...>::type;
 126
 127 #else
 128
 129 template<template<class...> class F, class... T> using mp_defer = mp_if<mp_valid<F, T...>, detail::mp_defer_impl<F, T...>, detail::mp_no_type>;
 130
 131 #endif
 132
 133 // mp_eval_if, mp_eval_if_c
 134 namespace detail
 135 {
 136
 137 template<bool C, class T, template<class...> class F, class... U> struct mp_eval_if_c_impl;
 138
 139 template<class T, template<class...> class F, class... U> struct mp_eval_if_c_impl<true, T, F, U...>
 140 {
 141     using type = T;
 142 };
 143
 144 template<class T, template<class...> class F, class... U> struct mp_eval_if_c_impl<false, T, F, U...>: mp_defer<F, U...>
 145 {
 146 };
 147
 148 } // namespace detail
 149
 150 template<bool C, class T, template<class...> class F, class... U> using mp_eval_if_c = typename detail::mp_eval_if_c_impl<C, T, F, U...>::type;
 151 template<class C, class T, template<class...> class F, class... U> using mp_eval_if = typename detail::mp_eval_if_c_impl<static_cast<bool>(C::value), T, F, U...>::type;
 152 template<class C, class T, class Q, class... U> using mp_eval_if_q = typename detail::mp_eval_if_c_impl<static_cast<bool>(C::value), T, Q::template fn, U...>::type;
 153
 154 // mp_eval_if_not
 155 template<class C, class T, template<class...> class F, class... U> using mp_eval_if_not = mp_eval_if<mp_not<C>, T, F, U...>;
 156 template<class C, class T, class Q, class... U> using mp_eval_if_not_q = mp_eval_if<mp_not<C>, T, Q::template fn, U...>;
 157
 158 // mp_eval_or
 159 template<class T, template<class...> class F, class... U> using mp_eval_or = mp_eval_if_not<mp_valid<F, U...>, T, F, U...>;
 160 template<class T, class Q, class... U> using mp_eval_or_q = mp_eval_or<T, Q::template fn, U...>;
 161
 162 // mp_cond
 163
 164 // so elegant; so doesn't work
 165 // template<class C, class T, class... E> using mp_cond = mp_eval_if<C, T, mp_cond, E...>;
 166
 167 namespace detail
 168 {
 169
 170 template<class C, class T, class... E> struct mp_cond_impl;
 171
 172 } // namespace detail
 173
 174 template<class C, class T, class... E> using mp_cond = typename detail::mp_cond_impl<C, T, E...>::type;
 175
 176 namespace detail
 177 {
 178
 179 template<class C, class T, class... E> using mp_cond_ = mp_eval_if<C, T, mp_cond, E...>;
 180
 181 template<class C, class T, class... E> struct mp_cond_impl: mp_defer<mp_cond_, C, T, E...>
 182 {
 183 };
 184
 185 } // namespace detail
 186
 187 // mp_quote
 188 template<template<class...> class F> struct mp_quote
 189 {
 190     // the indirection through mp_defer works around the language inability
 191     // to expand T... into a fixed parameter list of an alias template
 192
 193     template<class... T> using fn = typename mp_defer<F, T...>::type;
 194 };
 195
 196 // mp_quote_trait
 197 template<template<class...> class F> struct mp_quote_trait
 198 {
 199     template<class... T> using fn = typename F<T...>::type;
 200 };
 201
 202 // mp_invoke_q
 203 #if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1900 )
 204
 205 namespace detail
 206 {
 207
 208 template<class Q, class... T> struct mp_invoke_q_impl: mp_defer<Q::template fn, T...> {};
 209
 210 } // namespace detail
 211
 212 template<class Q, class... T> using mp_invoke_q = typename detail::mp_invoke_q_impl<Q, T...>::type;
 213
 214 #elif BOOST_MP11_WORKAROUND( BOOST_MP11_GCC, < 50000 )
 215
 216 template<class Q, class... T> using mp_invoke_q = typename mp_defer<Q::template fn, T...>::type;
 217
 218 #else
 219
 220 template<class Q, class... T> using mp_invoke_q = typename Q::template fn<T...>;
 221
 222 #endif
 223
 224 // mp_not_fn<P>
 225 template<template<class...> class P> struct mp_not_fn
 226 {
 227     template<class... T> using fn = mp_not< mp_invoke_q<mp_quote<P>, T...> >;
 228 };
 229
 230 template<class Q> using mp_not_fn_q = mp_not_fn<Q::template fn>;
 231
 232 // mp_compose
 233 namespace detail
 234 {
 235
 236 template<class T, class Q> using mp_reverse_invoke_q = mp_invoke_q<Q, T>;
 237
 238 } // namespace detail
 239
 240 #if !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1900 )
 241
 242 template<template<class...> class... F> struct mp_compose
 243 {
 244     template<class T> using fn = mp_fold<mp_list<mp_quote<F>...>, T, detail::mp_reverse_invoke_q>;
 245 };
 246
 247 #endif
 248
 249 template<class... Q> struct mp_compose_q
 250 {
 251     template<class T> using fn = mp_fold<mp_list<Q...>, T, detail::mp_reverse_invoke_q>;
 252 };
 253
 254 } // namespace mp11
 255 } // namespace boost
 256
 257 #endif // #ifndef BOOST_MP11_UTILITY_HPP_INCLUDED