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Diffstat (limited to 'include/mapbox/variant.hpp')
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diff --git a/include/mapbox/variant.hpp b/include/mapbox/variant.hpp new file mode 100644 index 0000000..fb0f77e --- /dev/null +++ b/include/mapbox/variant.hpp @@ -0,0 +1,1013 @@ +#ifndef MAPBOX_UTIL_VARIANT_HPP +#define MAPBOX_UTIL_VARIANT_HPP + +#include <cassert> +#include <cstddef> // size_t +#include <new> // operator new +#include <stdexcept> // runtime_error +#include <string> +#include <tuple> +#include <type_traits> +#include <typeinfo> +#include <utility> +#include <functional> + +#include <mapbox/recursive_wrapper.hpp> +#include <mapbox/variant_visitor.hpp> + +// clang-format off +// [[deprecated]] is only available in C++14, use this for the time being +#if __cplusplus <= 201103L +# ifdef __GNUC__ +# define MAPBOX_VARIANT_DEPRECATED __attribute__((deprecated)) +# elif defined(_MSC_VER) +# define MAPBOX_VARIANT_DEPRECATED __declspec(deprecated) +# else +# define MAPBOX_VARIANT_DEPRECATED +# endif +#else +# define MAPBOX_VARIANT_DEPRECATED [[deprecated]] +#endif + + +#ifdef _MSC_VER +// https://msdn.microsoft.com/en-us/library/bw1hbe6y.aspx +# ifdef NDEBUG +# define VARIANT_INLINE __forceinline +# else +# define VARIANT_INLINE //__declspec(noinline) +# endif +#else +# ifdef NDEBUG +# define VARIANT_INLINE //inline __attribute__((always_inline)) +# else +# define VARIANT_INLINE __attribute__((noinline)) +# endif +#endif +// clang-format on + +// Exceptions +#if defined( __EXCEPTIONS) || defined( _MSC_VER) +#define HAS_EXCEPTIONS +#endif + +#define VARIANT_MAJOR_VERSION 1 +#define VARIANT_MINOR_VERSION 1 +#define VARIANT_PATCH_VERSION 0 + +#define VARIANT_VERSION (VARIANT_MAJOR_VERSION * 100000) + (VARIANT_MINOR_VERSION * 100) + (VARIANT_PATCH_VERSION) + +namespace mapbox { +namespace util { + +// XXX This should derive from std::logic_error instead of std::runtime_error. +// See https://github.com/mapbox/variant/issues/48 for details. +class bad_variant_access : public std::runtime_error +{ + +public: + explicit bad_variant_access(const std::string& what_arg) + : runtime_error(what_arg) {} + + explicit bad_variant_access(const char* what_arg) + : runtime_error(what_arg) {} + +}; // class bad_variant_access + +template <typename R = void> +struct MAPBOX_VARIANT_DEPRECATED static_visitor +{ + using result_type = R; + +protected: + static_visitor() {} + ~static_visitor() {} +}; + +namespace detail { + +static constexpr std::size_t invalid_value = std::size_t(-1); + +template <typename T, typename... Types> +struct direct_type; + +template <typename T, typename First, typename... Types> +struct direct_type<T, First, Types...> +{ + static constexpr std::size_t index = std::is_same<T, First>::value + ? sizeof...(Types) + : direct_type<T, Types...>::index; +}; + +template <typename T> +struct direct_type<T> +{ + static constexpr std::size_t index = invalid_value; +}; + +#if __cpp_lib_logical_traits >= 201510L + +using std::disjunction; + +#else + +template <typename...> +struct disjunction : std::false_type {}; + +template <typename B1> +struct disjunction<B1> : B1 {}; + +template <typename B1, typename B2> +struct disjunction<B1, B2> : std::conditional<B1::value, B1, B2>::type {}; + +template <typename B1, typename... Bs> +struct disjunction<B1, Bs...> : std::conditional<B1::value, B1, disjunction<Bs...>>::type {}; + +#endif + +template <typename T, typename... Types> +struct convertible_type; + +template <typename T, typename First, typename... Types> +struct convertible_type<T, First, Types...> +{ + static constexpr std::size_t index = std::is_convertible<T, First>::value + ? disjunction<std::is_convertible<T, Types>...>::value ? invalid_value : sizeof...(Types) + : convertible_type<T, Types...>::index; +}; + +template <typename T> +struct convertible_type<T> +{ + static constexpr std::size_t index = invalid_value; +}; + +template <typename T, typename... Types> +struct value_traits +{ + using value_type = typename std::remove_const<typename std::remove_reference<T>::type>::type; + static constexpr std::size_t direct_index = direct_type<value_type, Types...>::index; + static constexpr bool is_direct = direct_index != invalid_value; + static constexpr std::size_t index = is_direct ? direct_index : convertible_type<value_type, Types...>::index; + static constexpr bool is_valid = index != invalid_value; + static constexpr std::size_t tindex = is_valid ? sizeof...(Types)-index : 0; + using target_type = typename std::tuple_element<tindex, std::tuple<void, Types...>>::type; +}; + +template <typename T, typename R = void> +struct enable_if_type +{ + using type = R; +}; + +template <typename F, typename V, typename Enable = void> +struct result_of_unary_visit +{ + using type = typename std::result_of<F(V&)>::type; +}; + +template <typename F, typename V> +struct result_of_unary_visit<F, V, typename enable_if_type<typename F::result_type>::type> +{ + using type = typename F::result_type; +}; + +template <typename F, typename V, typename Enable = void> +struct result_of_binary_visit +{ + using type = typename std::result_of<F(V&, V&)>::type; +}; + +template <typename F, typename V> +struct result_of_binary_visit<F, V, typename enable_if_type<typename F::result_type>::type> +{ + using type = typename F::result_type; +}; + +template <std::size_t arg1, std::size_t... others> +struct static_max; + +template <std::size_t arg> +struct static_max<arg> +{ + static const std::size_t value = arg; +}; + +template <std::size_t arg1, std::size_t arg2, std::size_t... others> +struct static_max<arg1, arg2, others...> +{ + static const std::size_t value = arg1 >= arg2 ? static_max<arg1, others...>::value : static_max<arg2, others...>::value; +}; + +template <typename... Types> +struct variant_helper; + +template <typename T, typename... Types> +struct variant_helper<T, Types...> +{ + VARIANT_INLINE static void destroy(const std::size_t type_index, void* data) + { + if (type_index == sizeof...(Types)) + { + reinterpret_cast<T*>(data)->~T(); + } + else + { + variant_helper<Types...>::destroy(type_index, data); + } + } + + VARIANT_INLINE static void move(const std::size_t old_type_index, void* old_value, void* new_value) + { + if (old_type_index == sizeof...(Types)) + { + new (new_value) T(std::move(*reinterpret_cast<T*>(old_value))); + } + else + { + variant_helper<Types...>::move(old_type_index, old_value, new_value); + } + } + + VARIANT_INLINE static void copy(const std::size_t old_type_index, const void* old_value, void* new_value) + { + if (old_type_index == sizeof...(Types)) + { + new (new_value) T(*reinterpret_cast<const T*>(old_value)); + } + else + { + variant_helper<Types...>::copy(old_type_index, old_value, new_value); + } + } +}; + +template <> +struct variant_helper<> +{ + VARIANT_INLINE static void destroy(const std::size_t, void*) {} + VARIANT_INLINE static void move(const std::size_t, void*, void*) {} + VARIANT_INLINE static void copy(const std::size_t, const void*, void*) {} +}; + +template <typename T> +struct unwrapper +{ + static T const& apply_const(T const& obj) { return obj; } + static T& apply(T& obj) { return obj; } +}; + +template <typename T> +struct unwrapper<recursive_wrapper<T>> +{ + static auto apply_const(recursive_wrapper<T> const& obj) + -> typename recursive_wrapper<T>::type const& + { + return obj.get(); + } + static auto apply(recursive_wrapper<T>& obj) + -> typename recursive_wrapper<T>::type& + { + return obj.get(); + } +}; + +template <typename T> +struct unwrapper<std::reference_wrapper<T>> +{ + static auto apply_const(std::reference_wrapper<T> const& obj) + -> typename std::reference_wrapper<T>::type const& + { + return obj.get(); + } + static auto apply(std::reference_wrapper<T>& obj) + -> typename std::reference_wrapper<T>::type& + { + return obj.get(); + } +}; + +template <typename F, typename V, typename R, typename... Types> +struct dispatcher; + +template <typename F, typename V, typename R, typename T, typename... Types> +struct dispatcher<F, V, R, T, Types...> +{ + VARIANT_INLINE static R apply_const(V const& v, F&& f) + { + if (v.template is<T>()) + { + return f(unwrapper<T>::apply_const(v.template get_unchecked<T>())); + } + else + { + return dispatcher<F, V, R, Types...>::apply_const(v, std::forward<F>(f)); + } + } + + VARIANT_INLINE static R apply(V& v, F&& f) + { + if (v.template is<T>()) + { + return f(unwrapper<T>::apply(v.template get_unchecked<T>())); + } + else + { + return dispatcher<F, V, R, Types...>::apply(v, std::forward<F>(f)); + } + } +}; + +template <typename F, typename V, typename R, typename T> +struct dispatcher<F, V, R, T> +{ + VARIANT_INLINE static R apply_const(V const& v, F&& f) + { + return f(unwrapper<T>::apply_const(v.template get_unchecked<T>())); + } + + VARIANT_INLINE static R apply(V& v, F&& f) + { + return f(unwrapper<T>::apply(v.template get_unchecked<T>())); + } +}; + +template <typename F, typename V, typename R, typename T, typename... Types> +struct binary_dispatcher_rhs; + +template <typename F, typename V, typename R, typename T0, typename T1, typename... Types> +struct binary_dispatcher_rhs<F, V, R, T0, T1, Types...> +{ + VARIANT_INLINE static R apply_const(V const& lhs, V const& rhs, F&& f) + { + if (rhs.template is<T1>()) // call binary functor + { + return f(unwrapper<T0>::apply_const(lhs.template get_unchecked<T0>()), + unwrapper<T1>::apply_const(rhs.template get_unchecked<T1>())); + } + else + { + return binary_dispatcher_rhs<F, V, R, T0, Types...>::apply_const(lhs, rhs, std::forward<F>(f)); + } + } + + VARIANT_INLINE static R apply(V& lhs, V& rhs, F&& f) + { + if (rhs.template is<T1>()) // call binary functor + { + return f(unwrapper<T0>::apply(lhs.template get_unchecked<T0>()), + unwrapper<T1>::apply(rhs.template get_unchecked<T1>())); + } + else + { + return binary_dispatcher_rhs<F, V, R, T0, Types...>::apply(lhs, rhs, std::forward<F>(f)); + } + } +}; + +template <typename F, typename V, typename R, typename T0, typename T1> +struct binary_dispatcher_rhs<F, V, R, T0, T1> +{ + VARIANT_INLINE static R apply_const(V const& lhs, V const& rhs, F&& f) + { + return f(unwrapper<T0>::apply_const(lhs.template get_unchecked<T0>()), + unwrapper<T1>::apply_const(rhs.template get_unchecked<T1>())); + } + + VARIANT_INLINE static R apply(V& lhs, V& rhs, F&& f) + { + return f(unwrapper<T0>::apply(lhs.template get_unchecked<T0>()), + unwrapper<T1>::apply(rhs.template get_unchecked<T1>())); + } +}; + +template <typename F, typename V, typename R, typename T, typename... Types> +struct binary_dispatcher_lhs; + +template <typename F, typename V, typename R, typename T0, typename T1, typename... Types> +struct binary_dispatcher_lhs<F, V, R, T0, T1, Types...> +{ + VARIANT_INLINE static R apply_const(V const& lhs, V const& rhs, F&& f) + { + if (lhs.template is<T1>()) // call binary functor + { + return f(unwrapper<T1>::apply_const(lhs.template get_unchecked<T1>()), + unwrapper<T0>::apply_const(rhs.template get_unchecked<T0>())); + } + else + { + return binary_dispatcher_lhs<F, V, R, T0, Types...>::apply_const(lhs, rhs, std::forward<F>(f)); + } + } + + VARIANT_INLINE static R apply(V& lhs, V& rhs, F&& f) + { + if (lhs.template is<T1>()) // call binary functor + { + return f(unwrapper<T1>::apply(lhs.template get_unchecked<T1>()), + unwrapper<T0>::apply(rhs.template get_unchecked<T0>())); + } + else + { + return binary_dispatcher_lhs<F, V, R, T0, Types...>::apply(lhs, rhs, std::forward<F>(f)); + } + } +}; + +template <typename F, typename V, typename R, typename T0, typename T1> +struct binary_dispatcher_lhs<F, V, R, T0, T1> +{ + VARIANT_INLINE static R apply_const(V const& lhs, V const& rhs, F&& f) + { + return f(unwrapper<T1>::apply_const(lhs.template get_unchecked<T1>()), + unwrapper<T0>::apply_const(rhs.template get_unchecked<T0>())); + } + + VARIANT_INLINE static R apply(V& lhs, V& rhs, F&& f) + { + return f(unwrapper<T1>::apply(lhs.template get_unchecked<T1>()), + unwrapper<T0>::apply(rhs.template get_unchecked<T0>())); + } +}; + +template <typename F, typename V, typename R, typename... Types> +struct binary_dispatcher; + +template <typename F, typename V, typename R, typename T, typename... Types> +struct binary_dispatcher<F, V, R, T, Types...> +{ + VARIANT_INLINE static R apply_const(V const& v0, V const& v1, F&& f) + { + if (v0.template is<T>()) + { + if (v1.template is<T>()) + { + return f(unwrapper<T>::apply_const(v0.template get_unchecked<T>()), + unwrapper<T>::apply_const(v1.template get_unchecked<T>())); // call binary functor + } + else + { + return binary_dispatcher_rhs<F, V, R, T, Types...>::apply_const(v0, v1, std::forward<F>(f)); + } + } + else if (v1.template is<T>()) + { + return binary_dispatcher_lhs<F, V, R, T, Types...>::apply_const(v0, v1, std::forward<F>(f)); + } + return binary_dispatcher<F, V, R, Types...>::apply_const(v0, v1, std::forward<F>(f)); + } + + VARIANT_INLINE static R apply(V& v0, V& v1, F&& f) + { + if (v0.template is<T>()) + { + if (v1.template is<T>()) + { + return f(unwrapper<T>::apply(v0.template get_unchecked<T>()), + unwrapper<T>::apply(v1.template get_unchecked<T>())); // call binary functor + } + else + { + return binary_dispatcher_rhs<F, V, R, T, Types...>::apply(v0, v1, std::forward<F>(f)); + } + } + else if (v1.template is<T>()) + { + return binary_dispatcher_lhs<F, V, R, T, Types...>::apply(v0, v1, std::forward<F>(f)); + } + return binary_dispatcher<F, V, R, Types...>::apply(v0, v1, std::forward<F>(f)); + } +}; + +template <typename F, typename V, typename R, typename T> +struct binary_dispatcher<F, V, R, T> +{ + VARIANT_INLINE static R apply_const(V const& v0, V const& v1, F&& f) + { + return f(unwrapper<T>::apply_const(v0.template get_unchecked<T>()), + unwrapper<T>::apply_const(v1.template get_unchecked<T>())); // call binary functor + } + + VARIANT_INLINE static R apply(V& v0, V& v1, F&& f) + { + return f(unwrapper<T>::apply(v0.template get_unchecked<T>()), + unwrapper<T>::apply(v1.template get_unchecked<T>())); // call binary functor + } +}; + +// comparator functors +struct equal_comp +{ + template <typename T> + bool operator()(T const& lhs, T const& rhs) const + { + return lhs == rhs; + } +}; + +struct less_comp +{ + template <typename T> + bool operator()(T const& lhs, T const& rhs) const + { + return lhs < rhs; + } +}; + +template <typename Variant, typename Comp> +class comparer +{ +public: + explicit comparer(Variant const& lhs) noexcept + : lhs_(lhs) {} + comparer& operator=(comparer const&) = delete; + // visitor + template <typename T> + bool operator()(T const& rhs_content) const + { + T const& lhs_content = lhs_.template get_unchecked<T>(); + return Comp()(lhs_content, rhs_content); + } + +private: + Variant const& lhs_; +}; + +// hashing visitor +struct hasher +{ + template <typename T> + std::size_t operator()(const T& hashable) const + { + return std::hash<T>{}(hashable); + } +}; + +} // namespace detail + +struct no_init +{ +}; + +template <typename... Types> +class variant +{ + static_assert(sizeof...(Types) > 0, "Template parameter type list of variant can not be empty"); + static_assert(!detail::disjunction<std::is_reference<Types>...>::value, "Variant can not hold reference types. Maybe use std::reference_wrapper?"); + +private: + static const std::size_t data_size = detail::static_max<sizeof(Types)...>::value; + static const std::size_t data_align = detail::static_max<alignof(Types)...>::value; +public: + struct adapted_variant_tag; + using types = std::tuple<Types...>; +private: + using first_type = typename std::tuple_element<0, types>::type; + using data_type = typename std::aligned_storage<data_size, data_align>::type; + using helper_type = detail::variant_helper<Types...>; + + std::size_t type_index; + data_type data; + +public: + VARIANT_INLINE variant() noexcept(std::is_nothrow_default_constructible<first_type>::value) + : type_index(sizeof...(Types)-1) + { + static_assert(std::is_default_constructible<first_type>::value, "First type in variant must be default constructible to allow default construction of variant"); + new (&data) first_type(); + } + + VARIANT_INLINE variant(no_init) noexcept + : type_index(detail::invalid_value) {} + + // http://isocpp.org/blog/2012/11/universal-references-in-c11-scott-meyers + template <typename T, typename Traits = detail::value_traits<T, Types...>, + typename Enable = typename std::enable_if<Traits::is_valid && !std::is_same<variant<Types...>, typename Traits::value_type>::value>::type > + VARIANT_INLINE variant(T&& val) noexcept(std::is_nothrow_constructible<typename Traits::target_type, T&&>::value) + : type_index(Traits::index) + { + new (&data) typename Traits::target_type(std::forward<T>(val)); + } + + VARIANT_INLINE variant(variant<Types...> const& old) + : type_index(old.type_index) + { + helper_type::copy(old.type_index, &old.data, &data); + } + + VARIANT_INLINE variant(variant<Types...>&& old) noexcept(std::is_nothrow_move_constructible<types>::value) + : type_index(old.type_index) + { + helper_type::move(old.type_index, &old.data, &data); + } + +private: + VARIANT_INLINE void copy_assign(variant<Types...> const& rhs) + { + helper_type::destroy(type_index, &data); + type_index = detail::invalid_value; + helper_type::copy(rhs.type_index, &rhs.data, &data); + type_index = rhs.type_index; + } + + VARIANT_INLINE void move_assign(variant<Types...>&& rhs) + { + helper_type::destroy(type_index, &data); + type_index = detail::invalid_value; + helper_type::move(rhs.type_index, &rhs.data, &data); + type_index = rhs.type_index; + } + +public: + VARIANT_INLINE variant<Types...>& operator=(variant<Types...>&& other) + { + move_assign(std::move(other)); + return *this; + } + + VARIANT_INLINE variant<Types...>& operator=(variant<Types...> const& other) + { + copy_assign(other); + return *this; + } + + // conversions + // move-assign + template <typename T> + VARIANT_INLINE variant<Types...>& operator=(T&& rhs) noexcept + { + variant<Types...> temp(std::forward<T>(rhs)); + move_assign(std::move(temp)); + return *this; + } + + // copy-assign + template <typename T> + VARIANT_INLINE variant<Types...>& operator=(T const& rhs) + { + variant<Types...> temp(rhs); + copy_assign(temp); + return *this; + } + + template <typename T, typename std::enable_if< + (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE bool is() const + { + return type_index == detail::direct_type<T, Types...>::index; + } + + template <typename T,typename std::enable_if< + (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE bool is() const + { + return type_index == detail::direct_type<recursive_wrapper<T>, Types...>::index; + } + + VARIANT_INLINE bool valid() const + { + return type_index != detail::invalid_value; + } + + template <typename T, typename... Args> + VARIANT_INLINE void set(Args&&... args) + { + helper_type::destroy(type_index, &data); + type_index = detail::invalid_value; + new (&data) T(std::forward<Args>(args)...); + type_index = detail::direct_type<T, Types...>::index; + } + + // get_unchecked<T>() + template <typename T, typename std::enable_if< + (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T& get_unchecked() + { + return *reinterpret_cast<T*>(&data); + } + +#ifdef HAS_EXCEPTIONS + // get<T>() + template <typename T, typename std::enable_if< + (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T& get() + { + if (type_index == detail::direct_type<T, Types...>::index) + { + return *reinterpret_cast<T*>(&data); + } + else + { + throw bad_variant_access("in get<T>()"); + } + } +#endif + + template <typename T, typename std::enable_if< + (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T const& get_unchecked() const + { + return *reinterpret_cast<T const*>(&data); + } + +#ifdef HAS_EXCEPTIONS + template <typename T, typename std::enable_if< + (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T const& get() const + { + if (type_index == detail::direct_type<T, Types...>::index) + { + return *reinterpret_cast<T const*>(&data); + } + else + { + throw bad_variant_access("in get<T>()"); + } + } +#endif + + // get_unchecked<T>() - T stored as recursive_wrapper<T> + template <typename T, typename std::enable_if< + (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T& get_unchecked() + { + return (*reinterpret_cast<recursive_wrapper<T>*>(&data)).get(); + } + +#ifdef HAS_EXCEPTIONS + // get<T>() - T stored as recursive_wrapper<T> + template <typename T, typename std::enable_if< + (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T& get() + { + if (type_index == detail::direct_type<recursive_wrapper<T>, Types...>::index) + { + return (*reinterpret_cast<recursive_wrapper<T>*>(&data)).get(); + } + else + { + throw bad_variant_access("in get<T>()"); + } + } +#endif + + template <typename T, typename std::enable_if< + (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T const& get_unchecked() const + { + return (*reinterpret_cast<recursive_wrapper<T> const*>(&data)).get(); + } + +#ifdef HAS_EXCEPTIONS + template <typename T, typename std::enable_if< + (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T const& get() const + { + if (type_index == detail::direct_type<recursive_wrapper<T>, Types...>::index) + { + return (*reinterpret_cast<recursive_wrapper<T> const*>(&data)).get(); + } + else + { + throw bad_variant_access("in get<T>()"); + } + } +#endif + + // get_unchecked<T>() - T stored as std::reference_wrapper<T> + template <typename T, typename std::enable_if< + (detail::direct_type<std::reference_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T& get_unchecked() + { + return (*reinterpret_cast<std::reference_wrapper<T>*>(&data)).get(); + } + +#ifdef HAS_EXCEPTIONS + // get<T>() - T stored as std::reference_wrapper<T> + template <typename T, typename std::enable_if< + (detail::direct_type<std::reference_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T& get() + { + if (type_index == detail::direct_type<std::reference_wrapper<T>, Types...>::index) + { + return (*reinterpret_cast<std::reference_wrapper<T>*>(&data)).get(); + } + else + { + throw bad_variant_access("in get<T>()"); + } + } +#endif + + template <typename T, typename std::enable_if< + (detail::direct_type<std::reference_wrapper<T const>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T const& get_unchecked() const + { + return (*reinterpret_cast<std::reference_wrapper<T const> const*>(&data)).get(); + } + +#ifdef HAS_EXCEPTIONS + template <typename T, typename std::enable_if< + (detail::direct_type<std::reference_wrapper<T const>, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE T const& get() const + { + if (type_index == detail::direct_type<std::reference_wrapper<T const>, Types...>::index) + { + return (*reinterpret_cast<std::reference_wrapper<T const> const*>(&data)).get(); + } + else + { + throw bad_variant_access("in get<T>()"); + } + } +#endif + + // This function is deprecated because it returns an internal index field. + // Use which() instead. + MAPBOX_VARIANT_DEPRECATED VARIANT_INLINE std::size_t get_type_index() const + { + return type_index; + } + + VARIANT_INLINE int which() const noexcept + { + return static_cast<int>(sizeof...(Types)-type_index - 1); + } + + template <typename T, typename std::enable_if< + (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr> + VARIANT_INLINE static constexpr int which() noexcept + { + return static_cast<int>(sizeof...(Types)-detail::direct_type<T, Types...>::index - 1); + } + + // visitor + // unary + template <typename F, typename V, typename R = typename detail::result_of_unary_visit<F, first_type>::type> + auto VARIANT_INLINE static visit(V const& v, F&& f) + -> decltype(detail::dispatcher<F, V, R, Types...>::apply_const(v, std::forward<F>(f))) + { + return detail::dispatcher<F, V, R, Types...>::apply_const(v, std::forward<F>(f)); + } + // non-const + template <typename F, typename V, typename R = typename detail::result_of_unary_visit<F, first_type>::type> + auto VARIANT_INLINE static visit(V& v, F&& f) + -> decltype(detail::dispatcher<F, V, R, Types...>::apply(v, std::forward<F>(f))) + { + return detail::dispatcher<F, V, R, Types...>::apply(v, std::forward<F>(f)); + } + + // binary + // const + template <typename F, typename V, typename R = typename detail::result_of_binary_visit<F, first_type>::type> + auto VARIANT_INLINE static binary_visit(V const& v0, V const& v1, F&& f) + -> decltype(detail::binary_dispatcher<F, V, R, Types...>::apply_const(v0, v1, std::forward<F>(f))) + { + return detail::binary_dispatcher<F, V, R, Types...>::apply_const(v0, v1, std::forward<F>(f)); + } + // non-const + template <typename F, typename V, typename R = typename detail::result_of_binary_visit<F, first_type>::type> + auto VARIANT_INLINE static binary_visit(V& v0, V& v1, F&& f) + -> decltype(detail::binary_dispatcher<F, V, R, Types...>::apply(v0, v1, std::forward<F>(f))) + { + return detail::binary_dispatcher<F, V, R, Types...>::apply(v0, v1, std::forward<F>(f)); + } + + // match + // unary + template <typename... Fs> + auto VARIANT_INLINE match(Fs&&... fs) const + -> decltype(variant::visit(*this, ::mapbox::util::make_visitor(std::forward<Fs>(fs)...))) + { + return variant::visit(*this, ::mapbox::util::make_visitor(std::forward<Fs>(fs)...)); + } + // non-const + template <typename... Fs> + auto VARIANT_INLINE match(Fs&&... fs) + -> decltype(variant::visit(*this, ::mapbox::util::make_visitor(std::forward<Fs>(fs)...))) + { + return variant::visit(*this, ::mapbox::util::make_visitor(std::forward<Fs>(fs)...)); + } + + ~variant() noexcept // no-throw destructor + { + helper_type::destroy(type_index, &data); + } + + // comparison operators + // equality + VARIANT_INLINE bool operator==(variant const& rhs) const + { + assert(valid() && rhs.valid()); + if (this->which() != rhs.which()) + { + return false; + } + detail::comparer<variant, detail::equal_comp> visitor(*this); + return visit(rhs, visitor); + } + + VARIANT_INLINE bool operator!=(variant const& rhs) const + { + return !(*this == rhs); + } + + // less than + VARIANT_INLINE bool operator<(variant const& rhs) const + { + assert(valid() && rhs.valid()); + if (this->which() != rhs.which()) + { + return this->which() < rhs.which(); + } + detail::comparer<variant, detail::less_comp> visitor(*this); + return visit(rhs, visitor); + } + VARIANT_INLINE bool operator>(variant const& rhs) const + { + return rhs < *this; + } + VARIANT_INLINE bool operator<=(variant const& rhs) const + { + return !(*this > rhs); + } + VARIANT_INLINE bool operator>=(variant const& rhs) const + { + return !(*this < rhs); + } +}; + +// unary visitor interface +// const +template <typename F, typename V> +auto VARIANT_INLINE apply_visitor(F&& f, V const& v) -> decltype(V::visit(v, std::forward<F>(f))) +{ + return V::visit(v, std::forward<F>(f)); +} + +// non-const +template <typename F, typename V> +auto VARIANT_INLINE apply_visitor(F&& f, V& v) -> decltype(V::visit(v, std::forward<F>(f))) +{ + return V::visit(v, std::forward<F>(f)); +} + +// binary visitor interface +// const +template <typename F, typename V> +auto VARIANT_INLINE apply_visitor(F&& f, V const& v0, V const& v1) -> decltype(V::binary_visit(v0, v1, std::forward<F>(f))) +{ + return V::binary_visit(v0, v1, std::forward<F>(f)); +} + +// non-const +template <typename F, typename V> +auto VARIANT_INLINE apply_visitor(F&& f, V& v0, V& v1) -> decltype(V::binary_visit(v0, v1, std::forward<F>(f))) +{ + return V::binary_visit(v0, v1, std::forward<F>(f)); +} + +// getter interface + +#ifdef HAS_EXCEPTIONS +template <typename ResultType, typename T> +auto get(T& var)->decltype(var.template get<ResultType>()) +{ + return var.template get<ResultType>(); +} +#endif + +template <typename ResultType, typename T> +ResultType& get_unchecked(T& var) +{ + return var.template get_unchecked<ResultType>(); +} + +#ifdef HAS_EXCEPTIONS +template <typename ResultType, typename T> +auto get(T const& var)->decltype(var.template get<ResultType>()) +{ + return var.template get<ResultType>(); +} +#endif + +template <typename ResultType, typename T> +ResultType const& get_unchecked(T const& var) +{ + return var.template get_unchecked<ResultType>(); +} +} // namespace util +} // namespace mapbox + +// hashable iff underlying types are hashable +namespace std { +template <typename... Types> +struct hash< ::mapbox::util::variant<Types...>> { + std::size_t operator()(const ::mapbox::util::variant<Types...>& v) const noexcept + { + return ::mapbox::util::apply_visitor(::mapbox::util::detail::hasher{}, v); + } +}; +} + +#endif // MAPBOX_UTIL_VARIANT_HPP |