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Add test/variant_swap

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This commit is contained in:
Peter Dimov
2017-05-31 03:36:08 +03:00
parent fd848a8698
commit 4bb5cdab60
3 changed files with 347 additions and 12 deletions
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include/boost/variant2/variant.hpp
+87 -12
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@@ -16,6 +16,7 @@
#include <exception>
#include <cassert>
#include <initializer_list>
#include <utility>
//
@@ -353,7 +354,7 @@ template<class... T> struct variant_base_impl<mp_true, mp_true, T...>
{
}
template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> i ) noexcept
template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> ) noexcept
{
size_t const J = I+1;
@@ -362,7 +363,7 @@ template<class... T> struct variant_base_impl<mp_true, mp_true, T...>
return st1_.get( mp_size_t<J>() );
}
template<std::size_t I> constexpr mp_at_c<variant<T...>, I> const& _get_impl( mp_size_t<I> i ) const noexcept
template<std::size_t I> constexpr mp_at_c<variant<T...>, I> const& _get_impl( mp_size_t<I> ) const noexcept
{
size_t const J = I+1;
@@ -407,7 +408,7 @@ template<class... T> struct variant_base_impl<mp_true, mp_false, T...>
{
}
template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> i ) noexcept
template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> ) noexcept
{
size_t const J = I+1;
@@ -417,7 +418,7 @@ template<class... T> struct variant_base_impl<mp_true, mp_false, T...>
return ix_ >= 0? st1_.get( j ): st2_.get( j );
}
template<std::size_t I> constexpr mp_at_c<variant<T...>, I> const& _get_impl( mp_size_t<I> i ) const noexcept
template<std::size_t I> constexpr mp_at_c<variant<T...>, I> const& _get_impl( mp_size_t<I> ) const noexcept
{
size_t const J = I+1;
@@ -478,7 +479,7 @@ template<class... T> struct variant_base_impl<mp_false, mp_true, T...>
_destroy();
}
template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> i ) noexcept
template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> ) noexcept
{
size_t const J = I+1;
@@ -487,7 +488,7 @@ template<class... T> struct variant_base_impl<mp_false, mp_true, T...>
return st1_.get( mp_size_t<J>() );
}
template<std::size_t I> constexpr mp_at_c<variant<T...>, I> const& _get_impl( mp_size_t<I> i ) const noexcept
template<std::size_t I> constexpr mp_at_c<variant<T...>, I> const& _get_impl( mp_size_t<I> ) const noexcept
{
size_t const J = I+1;
@@ -563,7 +564,7 @@ template<class... T> struct variant_base_impl<mp_false, mp_false, T...>
_destroy();
}
template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> i ) noexcept
template<std::size_t I> constexpr mp_at_c<variant<T...>, I>& _get_impl( mp_size_t<I> ) noexcept
{
size_t const J = I+1;
@@ -573,7 +574,7 @@ template<class... T> struct variant_base_impl<mp_false, mp_false, T...>
return ix_ >= 0? st1_.get( j ): st2_.get( j );
}
template<std::size_t I> constexpr mp_at_c<variant<T...>, I> const& _get_impl( mp_size_t<I> i ) const noexcept
template<std::size_t I> constexpr mp_at_c<variant<T...>, I> const& _get_impl( mp_size_t<I> ) const noexcept
{
size_t const J = I+1;
@@ -638,6 +639,55 @@ template<std::size_t I> struct is_in_place_index<in_place_index_t<I>>: std::true
} // namespace detail
// is_nothrow_swappable
namespace detail
{
namespace det2
{
using std::swap;
template<class T> using is_swappable_impl = decltype(swap(std::declval<T&>(), std::declval<T&>()));
#if BOOST_WORKAROUND( BOOST_MSVC, <= 1910 )
template<class T> struct is_nothrow_swappable_impl_
{
static constexpr bool value = noexcept(swap(std::declval<T&>(), std::declval<T&>()));
};
template<class T> using is_nothrow_swappable_impl = mp_bool< is_nothrow_swappable_impl_<T>::value >;
#else
template<class T> using is_nothrow_swappable_impl = std::enable_if_t<noexcept(swap(std::declval<T&>(), std::declval<T&>()))>;
#endif
} // namespace det2
template<class T> struct is_swappable: mp_valid<det2::is_swappable_impl, T>
{
};
#if BOOST_WORKAROUND( BOOST_MSVC, <= 1910 )
template<class T> struct is_nothrow_swappable: mp_eval_if<mp_not<is_swappable<T>>, mp_false, det2::is_nothrow_swappable_impl, T>
{
};
#else
template<class T> struct is_nothrow_swappable: mp_valid<det2::is_nothrow_swappable_impl, T>
{
};
#endif
} // namespace detail
// variant
template<class... T> class variant: private variant2::detail::variant_base<T...>
@@ -715,7 +765,7 @@ public:
{
mp_for_each<mp_iota_c<sizeof...(T)>>([&]( auto I ){
constexpr auto J = decltype(I)::value;
constexpr auto J = I.value;
if( J == r.index() )
{
@@ -738,7 +788,7 @@ public:
{
mp_for_each<mp_iota_c<sizeof...(T)>>([&]( auto I ){
constexpr auto J = decltype(I)::type::value;
constexpr auto J = I.value;
if( J == r.index() )
{
@@ -805,7 +855,29 @@ public:
// swap
void swap( variant& r ); // noexcept( ... )
void swap( variant& r ) noexcept( mp_all<std::is_nothrow_move_constructible<T>..., variant2::detail::is_nothrow_swappable<T>...>::value )
{
if( index() == r.index() )
{
mp_for_each<mp_iota_c<sizeof...(T)>>([&]( auto I ){
constexpr auto J = I.value;
if( J == this->index() )
{
using std::swap;
swap( get<J>(*this), get<J>(r) );
}
});
}
else
{
variant tmp( std::move(*this) );
*this = std::move( r );
r = std::move( tmp );
}
}
// private accessors
@@ -916,7 +988,10 @@ template<class... T> constexpr bool operator>=( variant<T...> const & v, variant
template<class Visitor, class... Variants> constexpr void visit( Visitor&&, Variants&&... );
// specialized algorithms
template<class... T> void swap( variant<T...> & v, variant<T...> & w ); // noexcept(see below );
template<class... T> void swap( variant<T...> & v, variant<T...> & w ) noexcept( noexcept(v.swap(w)) )
{
v.swap( w );
}
} // namespace variant2
} // namespace boost