mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-11-12 21:09:01 +00:00
282 lines
9 KiB
C++
282 lines
9 KiB
C++
#ifndef SPROUT_VARIANT_VARIANT_HPP
|
|
#define SPROUT_VARIANT_VARIANT_HPP
|
|
|
|
#include <cstddef>
|
|
#include <utility>
|
|
#include <stdexcept>
|
|
#include <type_traits>
|
|
#include <sprout/config.hpp>
|
|
#include <sprout/index_tuple.hpp>
|
|
#include <sprout/utility/operation.hpp>
|
|
#include <sprout/tuple/tuple.hpp>
|
|
#include <sprout/tuple/functions.hpp>
|
|
#include <sprout/type/type_tuple.hpp>
|
|
#include <sprout/type/algorithm/find_index.hpp>
|
|
|
|
namespace sprout {
|
|
namespace detail {
|
|
template<typename... Types>
|
|
class variant_impl {
|
|
protected:
|
|
typedef sprout::tuples::tuple<Types...> tuple_type;;
|
|
typedef sprout::types::type_tuple<typename std::decay<Types>::type...> uncvref_tuple_type;;
|
|
private:
|
|
template<typename T, sprout::index_t... Indexes>
|
|
static SPROUT_CONSTEXPR tuple_type init(T&& operand, sprout::index_tuple<Indexes...>) {
|
|
return sprout::tuples::make_clone<tuple_type>(
|
|
typename sprout::tuples::tuple_element<Indexes, tuple_type>::type()...,
|
|
sprout::forward<T>(operand)
|
|
);
|
|
}
|
|
protected:
|
|
tuple_type tuple_;
|
|
int which_;
|
|
protected:
|
|
SPROUT_CONSTEXPR variant_impl()
|
|
: tuple_()
|
|
, which_()
|
|
{}
|
|
template<typename T, typename Index>
|
|
SPROUT_CONSTEXPR variant_impl(T&& operand, Index)
|
|
: tuple_(init(sprout::forward<T>(operand), typename sprout::index_range<0, Index::value>::type()))
|
|
, which_(Index::value)
|
|
{
|
|
static_assert(Index::value < sizeof...(Types), "variant<>: invalid operand");
|
|
}
|
|
void swap(variant_impl& other) SPROUT_NOEXCEPT_EXPR(
|
|
SPROUT_NOEXCEPT_EXPR(swap(std::declval<tuple_type&>(), std::declval<tuple_type&>()))
|
|
)
|
|
{
|
|
using std::swap;
|
|
swap(tuple_, other.tuple_);
|
|
swap(which_, other.which_);
|
|
}
|
|
variant_impl& operator=(variant_impl const&) = default;
|
|
};
|
|
} // namespace detail
|
|
//
|
|
// variant
|
|
//
|
|
template<typename... Types>
|
|
class variant
|
|
: private sprout::detail::variant_impl<Types...>
|
|
{
|
|
private:
|
|
typedef sprout::detail::variant_impl<Types...> impl_type;;
|
|
typedef typename impl_type::uncvref_tuple_type uncvref_tuple_type;;
|
|
public:
|
|
typedef typename impl_type::tuple_type tuple_type;;
|
|
private:
|
|
template<int I>
|
|
static SPROUT_CONSTEXPR typename std::enable_if<
|
|
I == sizeof...(Types),
|
|
bool
|
|
>::type eq(tuple_type const& l, tuple_type const& r, int which) {
|
|
return false;
|
|
}
|
|
template<int I>
|
|
static SPROUT_CONSTEXPR typename std::enable_if<
|
|
I != sizeof...(Types),
|
|
bool
|
|
>::type eq(tuple_type const& l, tuple_type const& r, int which) {
|
|
return I == which
|
|
? sprout::tuples::get<I>(l) == sprout::tuples::get<I>(r)
|
|
: eq<I + 1>(l, r, which)
|
|
;
|
|
}
|
|
template<int I>
|
|
static SPROUT_CONSTEXPR typename std::enable_if<
|
|
static_cast<std::size_t>(I) == sizeof...(Types),
|
|
bool
|
|
>::type lt(tuple_type const& l, tuple_type const& r, int which) {
|
|
return false;
|
|
}
|
|
template<int I>
|
|
static SPROUT_CONSTEXPR typename std::enable_if<
|
|
static_cast<std::size_t>(I) != sizeof...(Types),
|
|
bool
|
|
>::type lt(tuple_type const& l, tuple_type const& r, int which) {
|
|
return I == which
|
|
? sprout::tuples::get<I>(l) < sprout::tuples::get<I>(r)
|
|
: lt<I + 1>(l, r, which)
|
|
;
|
|
}
|
|
template<int I, typename Elem, typename Traits>
|
|
static typename std::enable_if<
|
|
static_cast<std::size_t>(I) == sizeof...(Types),
|
|
std::basic_ostream<Elem, Traits>&
|
|
>::type output(std::basic_ostream<Elem, Traits>& os, tuple_type const& t, int which) {
|
|
return os;
|
|
}
|
|
template<int I, typename Elem, typename Traits>
|
|
static typename std::enable_if<
|
|
static_cast<std::size_t>(I) != sizeof...(Types),
|
|
std::basic_ostream<Elem, Traits>&
|
|
>::type output(std::basic_ostream<Elem, Traits>& os, tuple_type const& t, int which) {
|
|
return I == which
|
|
? os << sprout::tuples::get<I>(t)
|
|
: output<I + 1>(os, t, which)
|
|
;
|
|
}
|
|
template<int I, typename Tuple, typename Visitor>
|
|
static SPROUT_CONSTEXPR typename std::enable_if<
|
|
I == sizeof...(Types),
|
|
typename Visitor::result_type
|
|
>::type visit(Tuple&& t, Visitor&& v, int which) {
|
|
return typename Visitor::result_type();
|
|
}
|
|
template<int I, typename Tuple, typename Visitor>
|
|
static SPROUT_CONSTEXPR typename std::enable_if<
|
|
I != sizeof...(Types),
|
|
typename Visitor::result_type
|
|
>::type visit(Tuple&& t, Visitor&& v, int which) {
|
|
return I == which
|
|
? sprout::forward<Visitor>(v)(sprout::tuples::get<I>(sprout::forward<Tuple>(t)))
|
|
: visit<I + 1>(sprout::forward<Tuple>(t), sprout::forward<Visitor>(v), which)
|
|
;
|
|
}
|
|
private:
|
|
using impl_type::tuple_;
|
|
using impl_type::which_;
|
|
public:
|
|
// construct/copy/destruct
|
|
SPROUT_CONSTEXPR variant()
|
|
: impl_type()
|
|
{}
|
|
variant(variant const&) = default;
|
|
variant(variant&&) = default;
|
|
template<typename T>
|
|
SPROUT_CONSTEXPR variant(T&& operand)
|
|
: impl_type(
|
|
sprout::forward<T>(operand),
|
|
sprout::types::find_index<uncvref_tuple_type, typename std::decay<T>::type>()
|
|
)
|
|
{}
|
|
// modifiers
|
|
void swap(variant& other) SPROUT_NOEXCEPT_EXPR(SPROUT_NOEXCEPT_EXPR(impl_type::swap(other))) {
|
|
impl_type::swap(other);
|
|
}
|
|
variant& operator=(variant const& rhs) {
|
|
static_cast<impl_type&>(*this) = rhs;
|
|
return *this;
|
|
}
|
|
variant& operator=(variant&& rhs) SPROUT_NOEXCEPT_EXPR(std::is_nothrow_move_assignable<impl_type>::value) {
|
|
static_cast<impl_type&>(*this) = sprout::move(rhs);
|
|
return *this;
|
|
}
|
|
template<typename T>
|
|
variant& operator=(T&& rhs) {
|
|
static_cast<impl_type&>(*this) = variant(sprout::forward<T>(rhs));
|
|
return *this;
|
|
}
|
|
// queries
|
|
SPROUT_CONSTEXPR int which() const {
|
|
return which_;
|
|
}
|
|
SPROUT_CONSTEXPR bool empty() const {
|
|
return false;
|
|
}
|
|
// relational
|
|
friend SPROUT_CONSTEXPR bool operator==(variant const& lhs, variant const& rhs) {
|
|
return lhs.which_ == rhs.which_ && eq<0>(lhs.tuple_, rhs.tuple_, lhs.which_);
|
|
}
|
|
friend SPROUT_CONSTEXPR bool operator!=(variant const& lhs, variant const& rhs) {
|
|
return !(lhs == rhs);
|
|
}
|
|
friend SPROUT_CONSTEXPR bool operator<(variant const& lhs, variant const& rhs) {
|
|
return lhs.which_ < rhs.which_
|
|
|| (lhs.which_ == rhs.which_ && lt<0>(lhs.tuple_, rhs.tuple_, lhs.which_))
|
|
;
|
|
}
|
|
friend SPROUT_CONSTEXPR bool operator>(variant const& lhs, variant const& rhs) {
|
|
return rhs < lhs;
|
|
}
|
|
friend SPROUT_CONSTEXPR bool operator<=(variant const& lhs, variant const& rhs) {
|
|
return !(rhs < lhs);
|
|
}
|
|
friend SPROUT_CONSTEXPR bool operator>=(variant const& lhs, variant const& rhs) {
|
|
return !(lhs < rhs);
|
|
}
|
|
|
|
template<typename Elem, typename Traits>
|
|
friend std::basic_ostream<Elem, Traits>& operator<<(std::basic_ostream<Elem, Traits>& lhs, variant const& rhs) {
|
|
return output<0>(lhs, rhs.tuple_, rhs.which_);
|
|
}
|
|
// get support
|
|
template<std::size_t I>
|
|
SPROUT_CONSTEXPR typename std::enable_if<
|
|
I != sizeof...(Types),
|
|
typename sprout::tuples::tuple_element<I, tuple_type>::type const&
|
|
>::type get_at() const {
|
|
return I == static_cast<std::size_t>(which_)
|
|
? sprout::tuples::get<I>(tuple_)
|
|
: (throw std::domain_error("variant<>: bad get"), sprout::tuples::get<I>(tuple_))
|
|
;
|
|
}
|
|
template<std::size_t I>
|
|
typename std::enable_if<
|
|
I != sizeof...(Types),
|
|
typename sprout::tuples::tuple_element<I, tuple_type>::type&
|
|
>::type get_at() {
|
|
return I == which_
|
|
? sprout::tuples::get<I>(tuple_)
|
|
: (throw std::domain_error("variant<>: bad get"), sprout::tuples::get<I>(tuple_))
|
|
;
|
|
}
|
|
template<typename U>
|
|
SPROUT_CONSTEXPR typename std::enable_if<
|
|
sprout::types::find_index<tuple_type, U>::value != sizeof...(Types),
|
|
U const&
|
|
>::type get() const {
|
|
return get_at<sprout::types::find_index<tuple_type, U>::value>();
|
|
}
|
|
template<typename U>
|
|
typename std::enable_if<
|
|
sprout::types::find_index<tuple_type, U>::value != sizeof...(Types),
|
|
U&
|
|
>::type get() {
|
|
return get_at<sprout::types::find_index<tuple_type, U>::value>();
|
|
}
|
|
// visitation support
|
|
template<typename Visitor>
|
|
SPROUT_CONSTEXPR typename Visitor::result_type apply_visitor(Visitor&& visitor) const {
|
|
return visit(tuple_, sprout::forward<Visitor>(visitor), which_);
|
|
}
|
|
template<typename Visitor>
|
|
typename Visitor::result_type apply_visitor(Visitor&& visitor) {
|
|
return visit(tuple_, sprout::forward<Visitor>(visitor), which_);
|
|
}
|
|
};
|
|
|
|
//
|
|
// swap
|
|
//
|
|
template<typename... Types>
|
|
inline void swap(
|
|
sprout::variant<Types...>& lhs,
|
|
sprout::variant<Types...>& rhs
|
|
) SPROUT_NOEXCEPT_EXPR(SPROUT_NOEXCEPT_EXPR(lhs.swap(rhs)))
|
|
{
|
|
lhs.swap(rhs);
|
|
}
|
|
} // namespace sprout
|
|
|
|
namespace std {
|
|
//
|
|
// tuple_size
|
|
//
|
|
template<typename... Types>
|
|
struct tuple_size<sprout::variant<Types...> >
|
|
: public std::tuple_size<typename sprout::variant<Types...>::tuple_type>
|
|
{};
|
|
|
|
//
|
|
// tuple_element
|
|
//
|
|
template<std::size_t I, typename... Types>
|
|
struct tuple_element<I, sprout::variant<Types...> >
|
|
: public std::tuple_element<I, typename sprout::variant<Types...>::tuple_type>
|
|
{};
|
|
} // namespace std
|
|
|
|
#endif // #ifndef SPROUT_VARIANT_VARIANT_HPP
|