forked from Qortal/Brooklyn
1054 lines
32 KiB
C++
1054 lines
32 KiB
C++
#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 <limits>
|
|
|
|
#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
|
|
|
|
#if !defined(MAPBOX_VARIANT_MINIMIZE_SIZE)
|
|
using type_index_t = unsigned int;
|
|
#else
|
|
#if defined(MAPBOX_VARIANT_OPTIMIZE_FOR_SPEED)
|
|
using type_index_t = std::uint_fast8_t;
|
|
#else
|
|
using type_index_t = std::uint_least8_t;
|
|
#endif
|
|
#endif
|
|
|
|
namespace detail {
|
|
|
|
static constexpr type_index_t invalid_value = type_index_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 type_index_t index = std::is_same<T, First>::value
|
|
? sizeof...(Types)
|
|
: direct_type<T, Types...>::index;
|
|
};
|
|
|
|
template <typename T>
|
|
struct direct_type<T>
|
|
{
|
|
static constexpr type_index_t index = invalid_value;
|
|
};
|
|
|
|
#if __cpp_lib_logical_traits >= 201510L
|
|
|
|
using std::conjunction;
|
|
using std::disjunction;
|
|
|
|
#else
|
|
|
|
template <typename...>
|
|
struct conjunction : std::true_type {};
|
|
|
|
template <typename B1>
|
|
struct conjunction<B1> : B1 {};
|
|
|
|
template <typename B1, typename B2>
|
|
struct conjunction<B1, B2> : std::conditional<B1::value, B2, B1>::type {};
|
|
|
|
template <typename B1, typename... Bs>
|
|
struct conjunction<B1, Bs...> : std::conditional<B1::value, conjunction<Bs...>, B1>::type {};
|
|
|
|
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 type_index_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 type_index_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;
|
|
using value_type_wrapper = recursive_wrapper<value_type>;
|
|
static constexpr type_index_t direct_index = direct_type<value_type, Types...>::index;
|
|
static constexpr bool is_direct = direct_index != invalid_value;
|
|
static constexpr type_index_t index_direct_or_wrapper = is_direct ? direct_index : direct_type<value_type_wrapper, Types...>::index;
|
|
static constexpr bool is_direct_or_wrapper = index_direct_or_wrapper != invalid_value;
|
|
static constexpr type_index_t index = is_direct_or_wrapper ? index_direct_or_wrapper : convertible_type<value_type, Types...>::index;
|
|
static constexpr bool is_valid = index != invalid_value;
|
|
static constexpr type_index_t tindex = is_valid ? sizeof...(Types)-index : 0;
|
|
using target_type = typename std::tuple_element<tindex, std::tuple<void, Types...>>::type;
|
|
};
|
|
|
|
template <typename Src, typename Dest>
|
|
struct copy_cvref
|
|
{
|
|
using type = Dest;
|
|
};
|
|
|
|
template <typename Src, typename Dest>
|
|
struct copy_cvref<Src const&, Dest>
|
|
{
|
|
using type = Dest const&;
|
|
};
|
|
|
|
template <typename Src, typename Dest>
|
|
struct copy_cvref<Src&, Dest>
|
|
{
|
|
using type = Dest&;
|
|
};
|
|
|
|
template <typename Src, typename Dest>
|
|
struct copy_cvref<Src&&, Dest>
|
|
{
|
|
using type = Dest&&;
|
|
};
|
|
|
|
template <typename F, typename = void>
|
|
struct deduced_result_type
|
|
{};
|
|
|
|
template <typename F, typename... Args>
|
|
struct deduced_result_type<F(Args...), decltype((void)std::declval<F>()(std::declval<Args>()...))>
|
|
{
|
|
using type = decltype(std::declval<F>()(std::declval<Args>()...));
|
|
};
|
|
|
|
template <typename F, typename = void>
|
|
struct visitor_result_type : deduced_result_type<F>
|
|
{};
|
|
|
|
// specialization for explicit result_type member in visitor class
|
|
template <typename F, typename... Args>
|
|
struct visitor_result_type<F(Args...), decltype((void)std::declval<typename std::decay<F>::type::result_type>())>
|
|
{
|
|
using type = typename std::decay<F>::type::result_type;
|
|
};
|
|
|
|
template <typename F, typename T>
|
|
using result_of_unary_visit = typename visitor_result_type<F&&(T&&)>::type;
|
|
|
|
template <typename F, typename T>
|
|
using result_of_binary_visit = typename visitor_result_type<F&&(T&&, T&&)>::type;
|
|
|
|
template <type_index_t arg1, type_index_t... others>
|
|
struct static_max;
|
|
|
|
template <type_index_t arg>
|
|
struct static_max<arg>
|
|
{
|
|
static const type_index_t value = arg;
|
|
};
|
|
|
|
template <type_index_t arg1, type_index_t arg2, type_index_t... others>
|
|
struct static_max<arg1, arg2, others...>
|
|
{
|
|
static const type_index_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 type_index_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 type_index_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 type_index_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 type_index_t, void*) {}
|
|
VARIANT_INLINE static void move(const type_index_t, void*, void*) {}
|
|
VARIANT_INLINE static void copy(const type_index_t, const void*, void*) {}
|
|
};
|
|
|
|
template <typename T>
|
|
struct unwrapper
|
|
{
|
|
using value_type = T;
|
|
|
|
template <typename V>
|
|
static auto apply(typename std::remove_reference<V>::type& var)
|
|
-> typename std::enable_if<std::is_lvalue_reference<V>::value,
|
|
decltype(var.template get_unchecked<T>())>::type
|
|
{
|
|
return var.template get_unchecked<T>();
|
|
}
|
|
|
|
template <typename V>
|
|
static auto apply(typename std::remove_reference<V>::type& var)
|
|
-> typename std::enable_if<!std::is_lvalue_reference<V>::value,
|
|
decltype(std::move(var.template get_unchecked<T>()))>::type
|
|
{
|
|
return std::move(var.template get_unchecked<T>());
|
|
}
|
|
};
|
|
|
|
template <typename T>
|
|
struct unwrapper<recursive_wrapper<T>> : unwrapper<T>
|
|
{};
|
|
|
|
template <typename T>
|
|
struct unwrapper<std::reference_wrapper<T>> : unwrapper<T>
|
|
{};
|
|
|
|
template <typename R, typename... Types>
|
|
struct dispatcher;
|
|
|
|
template <typename R, typename T, typename... Types>
|
|
struct dispatcher<R, T, Types...>
|
|
{
|
|
template <typename V, typename F>
|
|
VARIANT_INLINE static R apply(V&& v, F&& f)
|
|
{
|
|
if (v.template is<T>())
|
|
{
|
|
return std::forward<F>(f)(unwrapper<T>::template apply<V>(v));
|
|
}
|
|
else
|
|
{
|
|
return dispatcher<R, Types...>::apply(std::forward<V>(v), std::forward<F>(f));
|
|
}
|
|
}
|
|
};
|
|
|
|
template <typename R, typename T>
|
|
struct dispatcher<R, T>
|
|
{
|
|
template <typename V, typename F>
|
|
VARIANT_INLINE static R apply(V&& v, F&& f)
|
|
{
|
|
return std::forward<F>(f)(unwrapper<T>::template apply<V>(v));
|
|
}
|
|
};
|
|
|
|
template <typename R, typename T, typename... Types>
|
|
struct binary_dispatcher_rhs;
|
|
|
|
template <typename R, typename T0, typename T1, typename... Types>
|
|
struct binary_dispatcher_rhs<R, T0, T1, Types...>
|
|
{
|
|
template <typename V, typename F>
|
|
VARIANT_INLINE static R apply(V&& lhs, V&& rhs, F&& f)
|
|
{
|
|
if (rhs.template is<T1>()) // call binary functor
|
|
{
|
|
return std::forward<F>(f)(unwrapper<T0>::template apply<V>(lhs),
|
|
unwrapper<T1>::template apply<V>(rhs));
|
|
}
|
|
else
|
|
{
|
|
return binary_dispatcher_rhs<R, T0, Types...>::apply(std::forward<V>(lhs),
|
|
std::forward<V>(rhs),
|
|
std::forward<F>(f));
|
|
}
|
|
}
|
|
};
|
|
|
|
template <typename R, typename T0, typename T1>
|
|
struct binary_dispatcher_rhs<R, T0, T1>
|
|
{
|
|
template <typename V, typename F>
|
|
VARIANT_INLINE static R apply(V&& lhs, V&& rhs, F&& f)
|
|
{
|
|
return std::forward<F>(f)(unwrapper<T0>::template apply<V>(lhs),
|
|
unwrapper<T1>::template apply<V>(rhs));
|
|
}
|
|
};
|
|
|
|
template <typename R, typename T, typename... Types>
|
|
struct binary_dispatcher_lhs;
|
|
|
|
template <typename R, typename T0, typename T1, typename... Types>
|
|
struct binary_dispatcher_lhs<R, T0, T1, Types...>
|
|
{
|
|
template <typename V, typename F>
|
|
VARIANT_INLINE static R apply(V&& lhs, V&& rhs, F&& f)
|
|
{
|
|
if (lhs.template is<T1>()) // call binary functor
|
|
{
|
|
return std::forward<F>(f)(unwrapper<T1>::template apply<V>(lhs),
|
|
unwrapper<T0>::template apply<V>(rhs));
|
|
}
|
|
else
|
|
{
|
|
return binary_dispatcher_lhs<R, T0, Types...>::apply(std::forward<V>(lhs),
|
|
std::forward<V>(rhs),
|
|
std::forward<F>(f));
|
|
}
|
|
}
|
|
};
|
|
|
|
template <typename R, typename T0, typename T1>
|
|
struct binary_dispatcher_lhs<R, T0, T1>
|
|
{
|
|
template <typename V, typename F>
|
|
VARIANT_INLINE static R apply(V&& lhs, V&& rhs, F&& f)
|
|
{
|
|
return std::forward<F>(f)(unwrapper<T1>::template apply<V>(lhs),
|
|
unwrapper<T0>::template apply<V>(rhs));
|
|
}
|
|
};
|
|
|
|
template <typename R, typename... Types>
|
|
struct binary_dispatcher;
|
|
|
|
template <typename R, typename T, typename... Types>
|
|
struct binary_dispatcher<R, T, Types...>
|
|
{
|
|
template <typename V, typename F>
|
|
VARIANT_INLINE static R apply(V&& v0, V&& v1, F&& f)
|
|
{
|
|
if (v0.template is<T>())
|
|
{
|
|
if (v1.template is<T>())
|
|
{
|
|
return std::forward<F>(f)(unwrapper<T>::template apply<V>(v0),
|
|
unwrapper<T>::template apply<V>(v1)); // call binary functor
|
|
}
|
|
else
|
|
{
|
|
return binary_dispatcher_rhs<R, T, Types...>::apply(std::forward<V>(v0),
|
|
std::forward<V>(v1),
|
|
std::forward<F>(f));
|
|
}
|
|
}
|
|
else if (v1.template is<T>())
|
|
{
|
|
return binary_dispatcher_lhs<R, T, Types...>::apply(std::forward<V>(v0),
|
|
std::forward<V>(v1),
|
|
std::forward<F>(f));
|
|
}
|
|
return binary_dispatcher<R, Types...>::apply(std::forward<V>(v0),
|
|
std::forward<V>(v1),
|
|
std::forward<F>(f));
|
|
}
|
|
};
|
|
|
|
template <typename R, typename T>
|
|
struct binary_dispatcher<R, T>
|
|
{
|
|
template <typename V, typename F>
|
|
VARIANT_INLINE static R apply(V&& v0, V&& v1, F&& f)
|
|
{
|
|
return std::forward<F>(f)(unwrapper<T>::template apply<V>(v0),
|
|
unwrapper<T>::template apply<V>(v1)); // 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?");
|
|
static_assert(!detail::disjunction<std::is_array<Types>...>::value, "Variant can not hold array types.");
|
|
static_assert(sizeof...(Types) < std::numeric_limits<type_index_t>::max(), "Internal index type must be able to accommodate all alternatives.");
|
|
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 unwrap_first_type = typename detail::unwrapper<first_type>::value_type;
|
|
using data_type = typename std::aligned_storage<data_size, data_align>::type;
|
|
using helper_type = detail::variant_helper<Types...>;
|
|
|
|
template <typename V, typename T = unwrap_first_type>
|
|
using alternative_ref = typename detail::copy_cvref<V, T>::type;
|
|
|
|
type_index_t type_index;
|
|
#ifdef __clang_analyzer__
|
|
data_type data {};
|
|
#else
|
|
data_type data;
|
|
#endif
|
|
|
|
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(detail::conjunction<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)
|
|
// note we check for nothrow-constructible, not nothrow-assignable, since
|
|
// move_assign uses move-construction via placement new.
|
|
noexcept(detail::conjunction<std::is_nothrow_move_constructible<Types>...>::value)
|
|
{
|
|
if (this == &other) { // playing safe in release mode, hit assertion in debug.
|
|
assert(false);
|
|
return *this;
|
|
}
|
|
move_assign(std::move(other));
|
|
return *this;
|
|
}
|
|
|
|
VARIANT_INLINE variant<Types...>& operator=(variant<Types...> const& other)
|
|
{
|
|
if (this != &other)
|
|
copy_assign(other);
|
|
return *this;
|
|
}
|
|
|
|
// conversions
|
|
// move-assign
|
|
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<Types...>& operator=(T&& rhs)
|
|
// not that we check is_nothrow_constructible<T>, not is_nothrow_move_assignable<T>,
|
|
// since we construct a temporary
|
|
noexcept(std::is_nothrow_constructible<typename Traits::target_type, T&&>::value
|
|
&& std::is_nothrow_move_assignable<variant<Types...>>::value)
|
|
{
|
|
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 type_index_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 T0 = alternative_ref<V>,
|
|
typename R = detail::result_of_unary_visit<F, T0>>
|
|
VARIANT_INLINE static R visit(V&& v, F&& f)
|
|
{
|
|
return detail::dispatcher<R, Types...>::apply(std::forward<V>(v), std::forward<F>(f));
|
|
}
|
|
|
|
// binary
|
|
template <typename F, typename V, typename T0 = alternative_ref<V>,
|
|
typename R = detail::result_of_binary_visit<F, T0>>
|
|
VARIANT_INLINE static R binary_visit(V&& v0, V&& v1, F&& f)
|
|
{
|
|
return detail::binary_dispatcher<R, Types...>::apply(std::forward<V>(v0),
|
|
std::forward<V>(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)...));
|
|
}
|
|
template <typename... Fs>
|
|
auto VARIANT_INLINE match(Fs&&... fs) &&
|
|
-> decltype(variant::visit(std::move(*this), ::mapbox::util::make_visitor(std::forward<Fs>(fs)...)))
|
|
{
|
|
return variant::visit(std::move(*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
|
|
template <typename F, typename V>
|
|
auto VARIANT_INLINE apply_visitor(F&& f, V&& v)
|
|
-> decltype(v.visit(std::forward<V>(v), std::forward<F>(f)))
|
|
{
|
|
return v.visit(std::forward<V>(v), std::forward<F>(f));
|
|
}
|
|
|
|
// binary visitor interface
|
|
template <typename F, typename V>
|
|
auto VARIANT_INLINE apply_visitor(F&& f, V&& v0, V&& v1)
|
|
-> decltype(v0.binary_visit(std::forward<V>(v0), std::forward<V>(v1), std::forward<F>(f)))
|
|
{
|
|
return v0.binary_visit(std::forward<V>(v0), std::forward<V>(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>();
|
|
}
|
|
// variant_size
|
|
template <typename T>
|
|
struct variant_size;
|
|
|
|
//variable templates is c++14
|
|
//template <typename T>
|
|
//constexpr std::size_t variant_size_v = variant_size<T>::value;
|
|
|
|
template <typename T>
|
|
struct variant_size<const T>
|
|
: variant_size<T> {};
|
|
|
|
template <typename T>
|
|
struct variant_size<volatile T>
|
|
: variant_size<T> {};
|
|
|
|
template <typename T>
|
|
struct variant_size<const volatile T>
|
|
: variant_size<T> {};
|
|
|
|
template <typename... Types>
|
|
struct variant_size<variant<Types...>>
|
|
: std::integral_constant<std::size_t, sizeof...(Types)> {};
|
|
|
|
// variant_alternative
|
|
template <std::size_t Index, typename T>
|
|
struct variant_alternative;
|
|
|
|
#if defined(__clang__)
|
|
#if __has_builtin(__type_pack_element)
|
|
#define has_type_pack_element
|
|
#endif
|
|
#endif
|
|
|
|
#if defined(has_type_pack_element)
|
|
template <std::size_t Index, typename ...Types>
|
|
struct variant_alternative<Index, variant<Types...>>
|
|
{
|
|
static_assert(sizeof...(Types) > Index , "Index out of range");
|
|
using type = __type_pack_element<Index, Types...>;
|
|
};
|
|
#else
|
|
template <std::size_t Index, typename First, typename...Types>
|
|
struct variant_alternative<Index, variant<First, Types...>>
|
|
: variant_alternative<Index - 1, variant<Types...>>
|
|
{
|
|
static_assert(sizeof...(Types) > Index -1 , "Index out of range");
|
|
};
|
|
|
|
template <typename First, typename...Types>
|
|
struct variant_alternative<0, variant<First, Types...>>
|
|
{
|
|
using type = First;
|
|
};
|
|
|
|
#endif
|
|
|
|
template <size_t Index, typename T>
|
|
using variant_alternative_t = typename variant_alternative<Index, T>::type;
|
|
|
|
template <size_t Index, typename T>
|
|
struct variant_alternative<Index, const T>
|
|
: std::add_const<variant_alternative<Index, T>> {};
|
|
|
|
template <size_t Index, typename T>
|
|
struct variant_alternative<Index, volatile T>
|
|
: std::add_volatile<variant_alternative<Index, T>> {};
|
|
|
|
template <size_t Index, typename T>
|
|
struct variant_alternative<Index, const volatile T>
|
|
: std::add_cv<variant_alternative<Index, T>> {};
|
|
|
|
} // 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
|