ceph/src/boost/libs/hana/test/detail/ebo.cpp

   1 // Copyright Louis Dionne 2013-2016
   2 // Distributed under the Boost Software License, Version 1.0.
   3 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   4
   5 #include <boost/hana/detail/ebo.hpp>
   6
   7 #include <boost/hana/assert.hpp>
   8
   9 #include <string>
  10 #include <type_traits>
  11 #include <utility>
  12 namespace hana = boost::hana;
  13 using hana::detail::ebo;
  14
  15
  16 template <int> struct empty { };
  17 template <int> struct idx;
  18 #ifdef BOOST_HANA_WORKAROUND_MSVC_EMPTYBASE
  19 template <typename ...Bases> struct __declspec(empty_bases) inherit : Bases... { };
  20 #else
  21 template <typename ...Bases> struct inherit : Bases... { };
  22 #endif
  23
  24 static_assert(sizeof(inherit<>) == sizeof(inherit<ebo<idx<0>, empty<0>>>), "");
  25 static_assert(sizeof(inherit<>) == sizeof(inherit<ebo<idx<0>, empty<0>>, ebo<idx<1>, empty<1>>>), "");
  26 static_assert(sizeof(inherit<>) == sizeof(inherit<ebo<idx<0>, empty<0>>, ebo<idx<1>, empty<1>>, ebo<idx<2>, empty<2>>>), "");
  27
  28
  29 int main() {
  30     // Test default-construction
  31     {
  32         constexpr ebo<idx<0>, int> e;
  33         static_assert(hana::detail::ebo_get<idx<0>>(e) == 0, "");
  34     }
  35
  36     // Test construction of a non-empty object
  37     {
  38         ebo<idx<0>, std::string> e{"foobar"};
  39         BOOST_HANA_RUNTIME_CHECK(hana::detail::ebo_get<idx<0>>(e) == "foobar");
  40     }
  41
  42     {
  43         ebo<idx<0>, std::string> e{};
  44         BOOST_HANA_RUNTIME_CHECK(hana::detail::ebo_get<idx<0>>(e) == "");
  45     }
  46
  47     // Test construction of a non default-constructible type
  48     {
  49         struct nodefault {
  50             nodefault() = delete;
  51             explicit nodefault(char const*) { }
  52         };
  53         ebo<idx<0>, nodefault> e{"foobar"};
  54     }
  55
  56     // Get lvalue, const lvalue and rvalue with a non-empty type
  57     {
  58         ebo<idx<0>, std::string> e{"foobar"};
  59         std::string& s = hana::detail::ebo_get<idx<0>>(e);
  60         BOOST_HANA_RUNTIME_CHECK(s == "foobar");
  61         s = "foobaz";
  62         BOOST_HANA_RUNTIME_CHECK(hana::detail::ebo_get<idx<0>>(e) == "foobaz");
  63     }
  64
  65     {
  66         ebo<idx<0>, std::string> const e{"foobar"};
  67         std::string const& s = hana::detail::ebo_get<idx<0>>(e);
  68         BOOST_HANA_RUNTIME_CHECK(s == "foobar");
  69     }
  70
  71     {
  72         ebo<idx<0>, std::string> e{"foobar"};
  73         std::string&& s = hana::detail::ebo_get<idx<0>>(std::move(e));
  74         BOOST_HANA_RUNTIME_CHECK(s == "foobar");
  75     }
  76
  77     // Get lvalue, const lvalue and rvalue with an empty type
  78     {
  79         ebo<idx<0>, empty<0>> e{};
  80         empty<0>& s = hana::detail::ebo_get<idx<0>>(e);
  81         (void)s;
  82     }
  83
  84     {
  85         ebo<idx<0>, empty<0>> const e{};
  86         empty<0> const& s = hana::detail::ebo_get<idx<0>>(e);
  87         (void)s;
  88     }
  89
  90     {
  91         ebo<idx<0>, empty<0>> e{};
  92         empty<0>&& s = hana::detail::ebo_get<idx<0>>(std::move(e));
  93         (void)s;
  94     }
  95 }