96 lines
2.7 KiB
C++
96 lines
2.7 KiB
C++
// Copyright Louis Dionne 2013-2022
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
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#include <boost/hana/detail/ebo.hpp>
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#include <boost/hana/assert.hpp>
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#include <string>
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#include <type_traits>
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#include <utility>
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namespace hana = boost::hana;
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using hana::detail::ebo;
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template <int> struct empty { };
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template <int> struct idx;
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#ifdef BOOST_HANA_WORKAROUND_MSVC_EMPTYBASE
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template <typename ...Bases> struct __declspec(empty_bases) inherit : Bases... { };
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#else
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template <typename ...Bases> struct inherit : Bases... { };
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#endif
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static_assert(sizeof(inherit<>) == sizeof(inherit<ebo<idx<0>, empty<0>>>), "");
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static_assert(sizeof(inherit<>) == sizeof(inherit<ebo<idx<0>, empty<0>>, ebo<idx<1>, empty<1>>>), "");
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static_assert(sizeof(inherit<>) == sizeof(inherit<ebo<idx<0>, empty<0>>, ebo<idx<1>, empty<1>>, ebo<idx<2>, empty<2>>>), "");
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int main() {
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// Test default-construction
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{
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constexpr ebo<idx<0>, int> e;
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static_assert(hana::detail::ebo_get<idx<0>>(e) == 0, "");
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}
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// Test construction of a non-empty object
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{
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ebo<idx<0>, std::string> e{"foobar"};
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BOOST_HANA_RUNTIME_CHECK(hana::detail::ebo_get<idx<0>>(e) == "foobar");
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}
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{
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ebo<idx<0>, std::string> e{};
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BOOST_HANA_RUNTIME_CHECK(hana::detail::ebo_get<idx<0>>(e) == "");
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}
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// Test construction of a non default-constructible type
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{
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struct nodefault {
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nodefault() = delete;
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explicit nodefault(char const*) { }
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};
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ebo<idx<0>, nodefault> e{"foobar"};
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}
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// Get lvalue, const lvalue and rvalue with a non-empty type
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{
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ebo<idx<0>, std::string> e{"foobar"};
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std::string& s = hana::detail::ebo_get<idx<0>>(e);
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BOOST_HANA_RUNTIME_CHECK(s == "foobar");
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s = "foobaz";
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BOOST_HANA_RUNTIME_CHECK(hana::detail::ebo_get<idx<0>>(e) == "foobaz");
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}
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{
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ebo<idx<0>, std::string> const e{"foobar"};
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std::string const& s = hana::detail::ebo_get<idx<0>>(e);
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BOOST_HANA_RUNTIME_CHECK(s == "foobar");
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}
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{
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ebo<idx<0>, std::string> e{"foobar"};
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std::string&& s = hana::detail::ebo_get<idx<0>>(std::move(e));
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BOOST_HANA_RUNTIME_CHECK(s == "foobar");
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}
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// Get lvalue, const lvalue and rvalue with an empty type
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{
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ebo<idx<0>, empty<0>> e{};
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empty<0>& s = hana::detail::ebo_get<idx<0>>(e);
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(void)s;
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}
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{
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ebo<idx<0>, empty<0>> const e{};
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empty<0> const& s = hana::detail::ebo_get<idx<0>>(e);
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(void)s;
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}
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{
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ebo<idx<0>, empty<0>> e{};
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empty<0>&& s = hana::detail::ebo_get<idx<0>>(std::move(e));
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(void)s;
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}
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}
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