ceph/src/Beast/include/beast/core/detail/type_traits.hpp

   1 //
   2 // Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7
   8 #ifndef BEAST_DETAIL_TYPE_TRAITS_HPP
   9 #define BEAST_DETAIL_TYPE_TRAITS_HPP
  10
  11 #include <tuple>
  12 #include <type_traits>
  13 #include <stdexcept>
  14 #include <string>
  15
  16 namespace beast {
  17 namespace detail {
  18
  19 template<class... Ts>
  20 struct make_void
  21 {
  22     using type = void;
  23 };
  24
  25 template<class... Ts>
  26 using void_t = typename make_void<Ts...>::type;
  27
  28 template<class... Ts>
  29 inline
  30 void
  31 ignore_unused(Ts const& ...)
  32 {
  33 }
  34
  35 template<class... Ts>
  36 inline
  37 void
  38 ignore_unused()
  39 {}
  40
  41 template<class U>
  42 std::size_t constexpr
  43 max_sizeof()
  44 {
  45     return sizeof(U);
  46 }
  47
  48 template<class U0, class U1, class... Us>
  49 std::size_t constexpr
  50 max_sizeof()
  51 {
  52     return
  53         max_sizeof<U0>() > max_sizeof<U1, Us...>() ?
  54         max_sizeof<U0>() : max_sizeof<U1, Us...>();
  55 }
  56
  57 template<unsigned N, class T, class... Tn>
  58 struct repeat_tuple_impl
  59 {
  60     using type = typename repeat_tuple_impl<
  61         N - 1, T, T, Tn...>::type;
  62 };
  63
  64 template<class T, class... Tn>
  65 struct repeat_tuple_impl<0, T, Tn...>
  66 {
  67     using type = std::tuple<T, Tn...>;
  68 };
  69
  70 template<unsigned N, class T>
  71 struct repeat_tuple
  72 {
  73     using type =
  74         typename repeat_tuple_impl<N-1, T>::type;
  75 };
  76
  77 template<class T>
  78 struct repeat_tuple<0, T>
  79 {
  80     using type = std::tuple<>;
  81 };
  82
  83 template<class Exception>
  84 Exception
  85 make_exception(char const* reason, char const* file, int line)
  86 {
  87         char const* n = file;
  88         for(auto p = file; *p; ++p)
  89                 if(*p == '\\' || *p == '/')
  90                         n = p + 1;
  91         return Exception{std::string(reason) + " (" +
  92                 n + ":" + std::to_string(line) + ")"};
  93 }
  94
  95 } // detail
  96 } // beast
  97
  98 #endif