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Add constexpr support to empty_value

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This commit is contained in:
Glen Fernandes 2022-08-06 18:53:40 -04:00
parent 4162dbed57
commit e3745b2072
3 changed files with 82 additions and 16 deletions
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32
include/boost/core/empty_value.hpp
View File

@ -56,37 +56,37 @@ public:
#if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
empty_value() = default;
#else
empty_value() { }
BOOST_CONSTEXPR empty_value() { }
#endif
empty_value(boost::empty_init_t)
BOOST_CONSTEXPR empty_value(boost::empty_init_t)
: value_() { }
#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
template<class U, class... Args>
empty_value(boost::empty_init_t, U&& value, Args&&... args)
BOOST_CONSTEXPR empty_value(boost::empty_init_t, U&& value, Args&&... args)
: value_(std::forward<U>(value), std::forward<Args>(args)...) { }
#else
template<class U>
empty_value(boost::empty_init_t, U&& value)
BOOST_CONSTEXPR empty_value(boost::empty_init_t, U&& value)
: value_(std::forward<U>(value)) { }
#endif
#else
template<class U>
empty_value(boost::empty_init_t, const U& value)
BOOST_CONSTEXPR empty_value(boost::empty_init_t, const U& value)
: value_(value) { }
template<class U>
empty_value(boost::empty_init_t, U& value)
BOOST_CONSTEXPR empty_value(boost::empty_init_t, U& value)
: value_(value) { }
#endif
const T& get() const BOOST_NOEXCEPT {
BOOST_CONSTEXPR const T& get() const BOOST_NOEXCEPT {
return value_;
}
T& get() BOOST_NOEXCEPT {
BOOST_CXX14_CONSTEXPR T& get() BOOST_NOEXCEPT {
return value_;
}
@ -104,37 +104,37 @@ public:
#if !defined(BOOST_NO_CXX11_DEFAULTED_FUNCTIONS)
empty_value() = default;
#else
empty_value() { }
BOOST_CONSTEXPR empty_value() { }
#endif
empty_value(boost::empty_init_t)
BOOST_CONSTEXPR empty_value(boost::empty_init_t)
: T() { }
#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
template<class U, class... Args>
empty_value(boost::empty_init_t, U&& value, Args&&... args)
BOOST_CONSTEXPR empty_value(boost::empty_init_t, U&& value, Args&&... args)
: T(std::forward<U>(value), std::forward<Args>(args)...) { }
#else
template<class U>
empty_value(boost::empty_init_t, U&& value)
BOOST_CONSTEXPR empty_value(boost::empty_init_t, U&& value)
: T(std::forward<U>(value)) { }
#endif
#else
template<class U>
empty_value(boost::empty_init_t, const U& value)
BOOST_CONSTEXPR empty_value(boost::empty_init_t, const U& value)
: T(value) { }
template<class U>
empty_value(boost::empty_init_t, U& value)
BOOST_CONSTEXPR empty_value(boost::empty_init_t, U& value)
: T(value) { }
#endif
const T& get() const BOOST_NOEXCEPT {
BOOST_CONSTEXPR const T& get() const BOOST_NOEXCEPT {
return *this;
}
T& get() BOOST_NOEXCEPT {
BOOST_CXX14_CONSTEXPR T& get() BOOST_NOEXCEPT {
return *this;
}
};

1
test/Jamfile.v2
View File

@ -203,6 +203,7 @@ compile first_scalar_constexpr_test.cpp ;
run empty_value_test.cpp ;
run empty_value_size_test.cpp ;
run empty_value_final_test.cpp ;
run empty_value_constexpr_test.cpp ;
run quick_exit_test.cpp ;
run-fail quick_exit_fail.cpp ;

65
test/empty_value_constexpr_test.cpp Normal file
View File

@ -0,0 +1,65 @@
/*
Copyright 2022 Glen Joseph Fernandes
(glenjofe@gmail.com)
Distributed under the Boost Software License, Version 1.0.
(http://www.boost.org/LICENSE_1_0.txt)
*/
#include <boost/config.hpp>
#if !defined(BOOST_NO_CXX11_CONSTEXPR)
#include <boost/core/empty_value.hpp>
#include <boost/core/lightweight_test.hpp>
struct empty {
constexpr int value() const {
return 1;
}
};
class type {
public:
explicit constexpr type(int count)
: value_(count) { }
constexpr int value() const {
return value_;
}
private:
int value_;
};
void test_int()
{
constexpr boost::empty_value<int> v(boost::empty_init_t(), 4);
constexpr int c = v.get();
BOOST_TEST_EQ(c, 4);
}
void test_empty()
{
constexpr boost::empty_value<empty> v = boost::empty_init_t();
constexpr int c = v.get().value();
BOOST_TEST_EQ(c, 1);
}
void test_type()
{
constexpr boost::empty_value<type> v(boost::empty_init_t(), 2);
constexpr int c = v.get().value();
BOOST_TEST_EQ(c, 2);
}
int main()
{
test_int();
test_empty();
test_type();
return boost::report_errors();
}
#else
int main()
{
return 0;
}
#endif