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authorMike Morris <michael.patrick.morris@gmail.com>2015-09-30 16:14:32 -0400
committerJohn Firebaugh <john.firebaugh@gmail.com>2015-09-30 15:34:40 -0700
commitb46c102eb0ec3ca2ff0b422831cb98fa2bdebcba (patch)
tree3525ee2dba9e77fadedda73446a549ac8ebddda5 /include/mbgl/util/variant.hpp
parent3d57f3ea7c6ae1f098668c37a8c5f79638b0e527 (diff)
downloadqtlocation-mapboxgl-b46c102eb0ec3ca2ff0b422831cb98fa2bdebcba.tar.gz
mason variant@1.0
Diffstat (limited to 'include/mbgl/util/variant.hpp')
-rw-r--r--include/mbgl/util/variant.hpp793
1 files changed, 0 insertions, 793 deletions
diff --git a/include/mbgl/util/variant.hpp b/include/mbgl/util/variant.hpp
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--- a/include/mbgl/util/variant.hpp
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@@ -1,793 +0,0 @@
-#ifndef MAPBOX_UTIL_VARIANT_HPP
-#define MAPBOX_UTIL_VARIANT_HPP
-
-#include <utility>
-#include <typeinfo>
-#include <type_traits>
-#include <stdexcept> // runtime_error
-#include <new> // operator new
-#include <cstddef> // size_t
-#include <iosfwd>
-#include <string>
-
-#include "recursive_wrapper.hpp"
-
-#ifdef _MSC_VER
- // http://msdn.microsoft.com/en-us/library/z8y1yy88.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
-
-#define VARIANT_MAJOR_VERSION 0
-#define VARIANT_MINOR_VERSION 1
-#define VARIANT_PATCH_VERSION 0
-
-// translates to 100
-#define VARIANT_VERSION (VARIANT_MAJOR_VERSION*100000) + (VARIANT_MINOR_VERSION*100) + (VARIANT_PATCH_VERSION)
-
-namespace mapbox { namespace util {
-
-// static visitor
-template <typename R = void>
-struct 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;
-};
-
-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
- ? 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
-{
- static constexpr std::size_t direct_index = direct_type<T, Types...>::index;
- static constexpr std::size_t index =
- (direct_index == invalid_value) ? convertible_type<T, Types...>::index : direct_index;
-};
-
-template <typename T, typename...Types>
-struct is_valid_type;
-
-template <typename T, typename First, typename... Types>
-struct is_valid_type<T, First, Types...>
-{
- static constexpr bool value = std::is_convertible<T, First>::value
- || is_valid_type<T, Types...>::value;
-};
-
-template <typename T>
-struct is_valid_type<T> : std::false_type {};
-
-template <std::size_t N, typename ... Types>
-struct select_type
-{
- static_assert(N < sizeof...(Types), "index out of bounds");
-};
-
-template <std::size_t N, typename T, typename ... Types>
-struct select_type<N, T, Types...>
-{
- using type = typename select_type<N - 1, Types...>::type;
-};
-
-template <typename T, typename ... Types>
-struct select_type<0, T, Types...>
-{
- using type = T;
-};
-
-
-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, class 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;
-};
-
-
-} // namespace detail
-
-
-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 id, void * data)
- {
- if (id == sizeof...(Types))
- {
- reinterpret_cast<T*>(data)->~T();
- }
- else
- {
- variant_helper<Types...>::destroy(id, data);
- }
- }
-
- VARIANT_INLINE static void move(const std::size_t old_id, void * old_value, void * new_value)
- {
- if (old_id == sizeof...(Types))
- {
- new (new_value) T(std::move(*reinterpret_cast<T*>(old_value)));
- //std::memcpy(new_value, old_value, sizeof(T));
- // ^^ DANGER: this should only be considered for relocatable types e.g built-in types
- // Also, I don't see any measurable performance benefit just yet
- }
- else
- {
- variant_helper<Types...>::move(old_id, old_value, new_value);
- }
- }
-
- VARIANT_INLINE static void copy(const std::size_t old_id, const void * old_value, void * new_value)
- {
- if (old_id == sizeof...(Types))
- {
- new (new_value) T(*reinterpret_cast<const T*>(old_value));
- }
- else
- {
- variant_helper<Types...>::copy(old_id, 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 *) {}
-};
-
-namespace detail {
-
-template <typename T>
-struct unwrapper
-{
- T const& operator() (T const& obj) const
- {
- return obj;
- }
-
- T& operator() (T & obj) const
- {
- return obj;
- }
-};
-
-
-template <typename T>
-struct unwrapper<recursive_wrapper<T>>
-{
- auto operator() (recursive_wrapper<T> const& obj) const
- -> typename recursive_wrapper<T>::type const&
- {
- 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...>
-{
- using result_type = R;
- VARIANT_INLINE static result_type apply_const(V const& v, F f)
- {
- if (v.get_type_index() == sizeof...(Types))
- {
- return f(unwrapper<T>()(v. template get<T>()));
- }
- else
- {
- return dispatcher<F, V, R, Types...>::apply_const(v, f);
- }
- }
-
- VARIANT_INLINE static result_type apply(V & v, F f)
- {
- if (v.get_type_index() == sizeof...(Types))
- {
- return f(unwrapper<T>()(v. template get<T>()));
- }
- else
- {
- return dispatcher<F, V, R, Types...>::apply(v, f);
- }
- }
-};
-
-template<typename F, typename V, typename R>
-struct dispatcher<F, V, R>
-{
- using result_type = R;
- VARIANT_INLINE static result_type apply_const(V const&, F)
- {
- throw std::runtime_error(std::string("unary dispatch: FAIL ") + typeid(V).name());
- }
-
- VARIANT_INLINE static result_type apply(V &, F)
- {
- throw std::runtime_error(std::string("unary dispatch: FAIL ") + typeid(V).name());
- }
-};
-
-
-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...>
-{
- using result_type = R;
- VARIANT_INLINE static result_type apply_const(V const& lhs, V const& rhs, F f)
- {
- if (rhs.get_type_index() == sizeof...(Types)) // call binary functor
- {
- return f(unwrapper<T0>()(lhs. template get<T0>()),
- unwrapper<T1>()(rhs. template get<T1>()));
- }
- else
- {
- return binary_dispatcher_rhs<F, V, R, T0, Types...>::apply_const(lhs, rhs, f);
- }
- }
-
- VARIANT_INLINE static result_type apply(V & lhs, V & rhs, F f)
- {
- if (rhs.get_type_index() == sizeof...(Types)) // call binary functor
- {
- return f(unwrapper<T0>()(lhs. template get<T0>()),
- unwrapper<T1>()(rhs. template get<T1>()));
- }
- else
- {
- return binary_dispatcher_rhs<F, V, R, T0, Types...>::apply(lhs, rhs, f);
- }
- }
-
-};
-
-template<typename F, typename V, typename R, typename T>
-struct binary_dispatcher_rhs<F, V, R, T>
-{
- using result_type = R;
- VARIANT_INLINE static result_type apply_const(V const&, V const&, F)
- {
- throw std::runtime_error("binary dispatch: FAIL");
- }
- VARIANT_INLINE static result_type apply(V &, V &, F)
- {
- throw std::runtime_error("binary dispatch: FAIL");
- }
-};
-
-
-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...>
-{
- using result_type = R;
- VARIANT_INLINE static result_type apply_const(V const& lhs, V const& rhs, F f)
- {
- if (lhs.get_type_index() == sizeof...(Types)) // call binary functor
- {
- return f(lhs. template get<T1>(), rhs. template get<T0>());
- }
- else
- {
- return binary_dispatcher_lhs<F, V, R, T0, Types...>::apply_const(lhs, rhs, f);
- }
- }
-
- VARIANT_INLINE static result_type apply(V & lhs, V & rhs, F f)
- {
- if (lhs.get_type_index() == sizeof...(Types)) // call binary functor
- {
- return f(lhs. template get<T1>(), rhs. template get<T0>());
- }
- else
- {
- return binary_dispatcher_lhs<F, V, R, T0, Types...>::apply(lhs, rhs, f);
- }
- }
-
-};
-
-template<typename F, typename V, typename R, typename T>
-struct binary_dispatcher_lhs<F, V, R, T>
-{
- using result_type = R;
- VARIANT_INLINE static result_type apply_const(V const&, V const&, F)
- {
- throw std::runtime_error("binary dispatch: FAIL");
- }
-
- VARIANT_INLINE static result_type apply(V &, V &, F)
- {
- throw std::runtime_error("binary dispatch: FAIL");
- }
-};
-
-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...>
-{
- using result_type = R;
- VARIANT_INLINE static result_type apply_const(V const& v0, V const& v1, F f)
- {
- if (v0.get_type_index() == sizeof...(Types))
- {
- if (v0.get_type_index() == v1.get_type_index())
- {
- return f(v0. template get<T>(), v1. template get<T>()); // call binary functor
- }
- else
- {
- return binary_dispatcher_rhs<F, V, R, T, Types...>::apply_const(v0, v1, f);
- }
- }
- else if (v1.get_type_index() == sizeof...(Types))
- {
- return binary_dispatcher_lhs<F, V, R, T, Types...>::apply_const(v0, v1, f);
- }
- return binary_dispatcher<F, V, R, Types...>::apply_const(v0, v1, f);
- }
-
- VARIANT_INLINE static result_type apply(V & v0, V & v1, F f)
- {
- if (v0.get_type_index() == sizeof...(Types))
- {
- if (v0.get_type_index() == v1.get_type_index())
- {
- return f(v0. template get<T>(), v1. template get<T>()); // call binary functor
- }
- else
- {
- return binary_dispatcher_rhs<F, V, R, T, Types...>::apply(v0, v1, f);
- }
- }
- else if (v1.get_type_index() == sizeof...(Types))
- {
- return binary_dispatcher_lhs<F, V, R, T, Types...>::apply(v0, v1, f);
- }
- return binary_dispatcher<F, V, R, Types...>::apply(v0, v1, f);
- }
-};
-
-template<typename F, typename V, typename R>
-struct binary_dispatcher<F, V, R>
-{
- using result_type = R;
- VARIANT_INLINE static result_type apply_const(V const&, V const&, F)
- {
- throw std::runtime_error("binary dispatch: FAIL");
- }
-
- VARIANT_INLINE static result_type apply(V &, V &, F)
- {
- throw std::runtime_error("binary dispatch: FAIL");
- }
-};
-
-// 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<T>();
- return Comp()(lhs_content, rhs_content);
- }
-private:
- Variant const& lhs_;
-};
-
-
-} // namespace detail
-
-struct no_init {};
-
-template<typename... Types>
-class variant
-{
-private:
-
- static const std::size_t data_size = static_max<sizeof(Types)...>::value;
- static const std::size_t data_align = static_max<alignof(Types)...>::value;
-
- using data_type = typename std::aligned_storage<data_size, data_align>::type;
- using helper_type = variant_helper<Types...>;
-
- std::size_t type_index;
- data_type data;
-
-public:
-
- VARIANT_INLINE variant()
- : type_index(sizeof...(Types) - 1)
- {
- new (&data) typename detail::select_type<0, Types...>::type();
- }
-
- VARIANT_INLINE variant(no_init)
- : type_index(detail::invalid_value) {}
-
- // http://isocpp.org/blog/2012/11/universal-references-in-c11-scott-meyers
- template <typename T, class = typename std::enable_if<
- detail::is_valid_type<typename std::remove_reference<T>::type, Types...>::value>::type>
- VARIANT_INLINE variant(T && val) noexcept
- : type_index(detail::value_traits<typename std::remove_reference<T>::type, Types...>::index)
- {
- constexpr std::size_t index = sizeof...(Types) - detail::value_traits<typename std::remove_reference<T>::type, Types...>::index - 1;
- using target_type = typename detail::select_type<index, Types...>::type;
- new (&data) target_type(std::forward<T>(val)); // nothrow
- }
-
- 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
- : type_index(old.type_index)
- {
- helper_type::move(old.type_index, &old.data, &data);
- }
-
- friend void swap(variant<Types...> & first, variant<Types...> & second)
- {
- using std::swap; //enable ADL
- swap(first.type_index, second.type_index);
- swap(first.data, second.data);
- }
-
- VARIANT_INLINE variant<Types...>& operator=(variant<Types...> other)
- {
- swap(*this, other);
- return *this;
- }
-
- // conversions
- // move-assign
- template <typename T>
- VARIANT_INLINE variant<Types...>& operator=(T && rhs) noexcept
- {
- variant<Types...> temp(std::forward<T>(rhs));
- swap(*this, temp);
- return *this;
- }
-
- // copy-assign
- template <typename T>
- VARIANT_INLINE variant<Types...>& operator=(T const& rhs)
- {
- variant<Types...> temp(rhs);
- swap(*this, temp);
- return *this;
- }
-
- template<typename T>
- VARIANT_INLINE bool is() const
- {
- return (type_index == detail::direct_type<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);
- new (&data) T(std::forward<Args>(args)...);
- type_index = detail::direct_type<T, Types...>::index;
- }
-
- // 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 std::runtime_error("in get<T>()");
- }
- }
-
- 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 std::runtime_error("in get<T>()");
- }
- }
-
- // 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 std::runtime_error("in get<T>()");
- }
- }
-
- 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 std::runtime_error("in get<T>()");
- }
- }
- 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);
- }
-
- // visitor
- // unary
- template <typename F, typename V>
- auto VARIANT_INLINE
- static visit(V const& v, F f)
- -> decltype(detail::dispatcher<F, V,
- typename detail::result_of_unary_visit<F,
- typename detail::select_type<0, Types...>::type>::type, Types...>::apply_const(v, f))
- {
- using R = typename detail::result_of_unary_visit<F, typename detail::select_type<0, Types...>::type>::type;
- return detail::dispatcher<F, V, R, Types...>::apply_const(v, f);
- }
- // non-const
- template <typename F, typename V>
- auto VARIANT_INLINE
- static visit(V & v, F f)
- -> decltype(detail::dispatcher<F, V,
- typename detail::result_of_unary_visit<F,
- typename detail::select_type<0, Types...>::type>::type, Types...>::apply(v, f))
- {
- using R = typename detail::result_of_unary_visit<F, typename detail::select_type<0, Types...>::type>::type;
- return detail::dispatcher<F, V, R, Types...>::apply(v, f);
- }
-
- // binary
- // const
- template <typename F, typename V>
- auto VARIANT_INLINE
- static binary_visit(V const& v0, V const& v1, F f)
- -> decltype(detail::binary_dispatcher<F, V,
- typename detail::result_of_binary_visit<F,
- typename detail::select_type<0, Types...>::type>::type, Types...>::apply_const(v0, v1, f))
- {
- using R = typename detail::result_of_binary_visit<F,typename detail::select_type<0, Types...>::type>::type;
- return detail::binary_dispatcher<F, V, R, Types...>::apply_const(v0, v1, f);
- }
- // non-const
- template <typename F, typename V>
- auto VARIANT_INLINE
- static binary_visit(V& v0, V& v1, F f)
- -> decltype(detail::binary_dispatcher<F, V,
- typename detail::result_of_binary_visit<F,
- typename detail::select_type<0, Types...>::type>::type, Types...>::apply(v0, v1, f))
- {
- using R = typename detail::result_of_binary_visit<F,typename detail::select_type<0, Types...>::type>::type;
- return detail::binary_dispatcher<F, V, R, Types...>::apply(v0, v1, f);
- }
-
- ~variant() noexcept
- {
- helper_type::destroy(type_index, &data);
- }
-
- // comparison operators
- // equality
- VARIANT_INLINE bool operator==(variant const& rhs) const
- {
- if (this->get_type_index() != rhs.get_type_index())
- return false;
- detail::comparer<variant, detail::equal_comp> visitor(*this);
- return visit(rhs, visitor);
- }
- // less than
- VARIANT_INLINE bool operator<(variant const& rhs) const
- {
- if (this->get_type_index() != rhs.get_type_index())
- {
- return this->get_type_index() < rhs.get_type_index();
- // ^^ borrowed from boost::variant
- }
- detail::comparer<variant, detail::less_comp> visitor(*this);
- return visit(rhs, visitor);
- }
-};
-
-// unary visitor interface
-
-// const
-template <typename V, typename F>
-auto VARIANT_INLINE static apply_visitor(F f, V const& v) -> decltype(V::visit(v, f))
-{
- return V::visit(v, f);
-}
-// non-const
-template <typename V, typename F>
-auto VARIANT_INLINE static apply_visitor(F f, V & v) -> decltype(V::visit(v, f))
-{
- return V::visit(v, f);
-}
-
-// binary visitor interface
-// const
-template <typename V, typename F>
-auto VARIANT_INLINE static apply_visitor(F f, V const& v0, V const& v1) -> decltype(V::binary_visit(v0, v1, f))
-{
- return V::binary_visit(v0, v1, f);
-}
-// non-const
-template <typename V, typename F>
-auto VARIANT_INLINE static apply_visitor(F f, V & v0, V & v1) -> decltype(V::binary_visit(v0, v1, f))
-{
- return V::binary_visit(v0, v1, f);
-}
-
-// getter interface
-template<typename ResultType, typename T>
-ResultType & get(T & var)
-{
- return var.template get<ResultType>();
-}
-
-template<typename ResultType, typename T>
-ResultType const& get(T const& var)
-{
- return var.template get<ResultType>();
-}
-
-
-}}
-
-#endif // MAPBOX_UTIL_VARIANT_HPP