Revision f2f76082dfcbfa39a6dfecb5afa1bf961316a51b authored by Eric Fischer on 01 December 2017, 22:35:03 UTC, committed by GitHub on 01 December 2017, 22:35:03 UTC
Clean up duplicated code for reading tiles from a directory
variant.hpp
#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
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