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
main()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 }
96