src/hb-meta.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2018  Google, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
  *
  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Google Author(s): Behdad Esfahbod
  */

 #ifndef HB_META_HH
 #define HB_META_HH

 #include "hb.hh"

 #include <memory>
 #include <type_traits>
 #include <utility>


 /*
  * C++ template meta-programming & fundamentals used with them.
  */

 /* Void!  For when we need a expression-type of void. */
 struct hb_empty_t {};

 /* https://en.cppreference.com/w/cpp/types/void_t */
 template<typename... Ts> struct _hb_void_t { typedef void type; };
 template<typename... Ts> using hb_void_t = typename _hb_void_t<Ts...>::type;

 template<typename Head, typename... Ts> struct _hb_head_t { typedef Head type; };
 template<typename... Ts> using hb_head_t = typename _hb_head_t<Ts...>::type;

 template <typename T, T v> struct hb_integral_constant { static constexpr T value = v; };
 template <bool b> using hb_bool_constant = hb_integral_constant<bool, b>;
 using hb_true_type = hb_bool_constant<true>;
 using hb_false_type = hb_bool_constant<false>;

 /* Static-assert as expression. */
 template <bool cond> struct static_assert_expr;
 template <> struct static_assert_expr<true> : hb_false_type {};
 #define static_assert_expr(C) static_assert_expr<C>::value

 /* Basic type SFINAE. */

 template <bool B, typename T = void> struct hb_enable_if {};
 template <typename T>                struct hb_enable_if<true, T> { typedef T type; };
 #define hb_enable_if(Cond) typename hb_enable_if<(Cond)>::type* = nullptr
 /* Concepts/Requires alias: */
 #define hb_requires(Cond) hb_enable_if((Cond))

 template <typename T, typename T2> struct hb_is_same : hb_false_type {};
 template <typename T>              struct hb_is_same<T, T> : hb_true_type {};
 #define hb_is_same(T, T2) hb_is_same<T, T2>::value

 /* Function overloading SFINAE and priority. */

 #define HB_RETURN(Ret, E) -> hb_head_t<Ret, decltype ((E))> { return (E); }
 #define HB_AUTO_RETURN(E) -> decltype ((E)) { return (E); }
 #define HB_VOID_RETURN(E) -> hb_void_t<decltype ((E))> { (E); }

 template <unsigned Pri> struct hb_priority : hb_priority<Pri - 1> {};
 template <>             struct hb_priority<0> {};
 #define hb_prioritize hb_priority<16> ()

 #define HB_FUNCOBJ(x) static_const x HB_UNUSED


 template <typename T> struct hb_type_identity_t { typedef T type; };
 template <typename T> using hb_type_identity = typename hb_type_identity_t<T>::type;

 template <typename T> static inline T hb_declval ();
 #define hb_declval(T) (hb_declval<T> ())

 template <typename T> struct hb_match_const		: hb_type_identity_t<T>, hb_false_type	{};
 template <typename T> struct hb_match_const<const T>	: hb_type_identity_t<T>, hb_true_type	{};
 template <typename T> using hb_remove_const = typename hb_match_const<T>::type;

 template <typename T> struct hb_match_reference		: hb_type_identity_t<T>, hb_false_type	{};
 template <typename T> struct hb_match_reference<T &>	: hb_type_identity_t<T>, hb_true_type	{};
 template <typename T> struct hb_match_reference<T &&>	: hb_type_identity_t<T>, hb_true_type	{};
 template <typename T> using hb_remove_reference = typename hb_match_reference<T>::type;
 template <typename T> auto _hb_try_add_lvalue_reference (hb_priority<1>) -> hb_type_identity<T&>;
 template <typename T> auto _hb_try_add_lvalue_reference (hb_priority<0>) -> hb_type_identity<T>;
 template <typename T> using hb_add_lvalue_reference = decltype (_hb_try_add_lvalue_reference<T> (hb_prioritize));
 template <typename T> auto _hb_try_add_rvalue_reference (hb_priority<1>) -> hb_type_identity<T&&>;
 template <typename T> auto _hb_try_add_rvalue_reference (hb_priority<0>) -> hb_type_identity<T>;
 template <typename T> using hb_add_rvalue_reference = decltype (_hb_try_add_rvalue_reference<T> (hb_prioritize));

 template <typename T> struct hb_match_pointer		: hb_type_identity_t<T>, hb_false_type	{};
 template <typename T> struct hb_match_pointer<T *>	: hb_type_identity_t<T>, hb_true_type	{};
 template <typename T> using hb_remove_pointer = typename hb_match_pointer<T>::type;
 template <typename T> auto _hb_try_add_pointer (hb_priority<1>) -> hb_type_identity<hb_remove_reference<T>*>;
 template <typename T> auto _hb_try_add_pointer (hb_priority<1>) -> hb_type_identity<T>;
 template <typename T> using hb_add_pointer = decltype (_hb_try_add_pointer<T> (hb_prioritize));


 template <typename T> using hb_decay = typename std::decay<T>::type;

 #define hb_is_convertible(From,To) std::is_convertible<From, To>::value

 template <typename From, typename To>
 using hb_is_cr_convertible = hb_bool_constant<
   hb_is_same (hb_decay<From>, hb_decay<To>) &&
   (!std::is_const<From>::value || std::is_const<To>::value) &&
   (!std::is_reference<To>::value || std::is_const<To>::value || std::is_reference<To>::value)
 >;
 #define hb_is_cr_convertible(From,To) hb_is_cr_convertible<From, To>::value


 struct
 {
   template <typename T> constexpr auto
   operator () (T&& v) const HB_AUTO_RETURN (std::forward<T> (v))

   template <typename T> constexpr auto
   operator () (T *v) const HB_AUTO_RETURN (*v)

   template <typename T> constexpr auto
   operator () (const hb::shared_ptr<T>& v) const HB_AUTO_RETURN (*v)

   template <typename T> constexpr auto
   operator () (hb::shared_ptr<T>& v) const HB_AUTO_RETURN (*v)

   template <typename T> constexpr auto
   operator () (const hb::unique_ptr<T>& v) const HB_AUTO_RETURN (*v)

   template <typename T> constexpr auto
   operator () (hb::unique_ptr<T>& v) const HB_AUTO_RETURN (*v)
 }
 HB_FUNCOBJ (hb_deref);

 template <typename T>
 struct hb_reference_wrapper
 {
   hb_reference_wrapper (T v) : v (v) {}
   bool operator == (const hb_reference_wrapper& o) const { return v == o.v; }
   bool operator != (const hb_reference_wrapper& o) const { return v != o.v; }
   operator T& () { return v; }
   T& get () { return v; }
   T v;
 };
 template <typename T>
 struct hb_reference_wrapper<T&>
 {
   hb_reference_wrapper (T& v) : v (std::addressof (v)) {}
   bool operator == (const hb_reference_wrapper& o) const { return v == o.v; }
   bool operator != (const hb_reference_wrapper& o) const { return v != o.v; }
   operator T& () { return *v; }
   T& get () { return *v; }
   T* v;
 };


 /* Type traits */

 template <typename T> struct hb_int_min;
 template <> struct hb_int_min<char>			: hb_integral_constant<char,			CHAR_MIN>	{};
 template <> struct hb_int_min<signed char>		: hb_integral_constant<signed char,		SCHAR_MIN>	{};
 template <> struct hb_int_min<unsigned char>		: hb_integral_constant<unsigned char,		0>		{};
 template <> struct hb_int_min<signed short>		: hb_integral_constant<signed short,		SHRT_MIN>	{};
 template <> struct hb_int_min<unsigned short>		: hb_integral_constant<unsigned short,		0>		{};
 template <> struct hb_int_min<signed int>		: hb_integral_constant<signed int,		INT_MIN>	{};
 template <> struct hb_int_min<unsigned int>		: hb_integral_constant<unsigned int,		0>		{};
 template <> struct hb_int_min<signed long>		: hb_integral_constant<signed long,		LONG_MIN>	{};
 template <> struct hb_int_min<unsigned long>		: hb_integral_constant<unsigned long,		0>		{};
 template <> struct hb_int_min<signed long long>		: hb_integral_constant<signed long long,	LLONG_MIN>	{};
 template <> struct hb_int_min<unsigned long long>	: hb_integral_constant<unsigned long long,	0>		{};
 template <typename T> struct hb_int_min<T *>		: hb_integral_constant<T *,			nullptr>	{};
 #define hb_int_min(T) hb_int_min<T>::value
 template <typename T> struct hb_int_max;
 template <> struct hb_int_max<char>			: hb_integral_constant<char,			CHAR_MAX>	{};
 template <> struct hb_int_max<signed char>		: hb_integral_constant<signed char,		SCHAR_MAX>	{};
 template <> struct hb_int_max<unsigned char>		: hb_integral_constant<unsigned char,		UCHAR_MAX>	{};
 template <> struct hb_int_max<signed short>		: hb_integral_constant<signed short,		SHRT_MAX>	{};
 template <> struct hb_int_max<unsigned short>		: hb_integral_constant<unsigned short,		USHRT_MAX>	{};
 template <> struct hb_int_max<signed int>		: hb_integral_constant<signed int,		INT_MAX>	{};
 template <> struct hb_int_max<unsigned int>		: hb_integral_constant<unsigned int,		UINT_MAX>	{};
 template <> struct hb_int_max<signed long>		: hb_integral_constant<signed long,		LONG_MAX>	{};
 template <> struct hb_int_max<unsigned long>		: hb_integral_constant<unsigned long,		ULONG_MAX>	{};
 template <> struct hb_int_max<signed long long>		: hb_integral_constant<signed long long,	LLONG_MAX>	{};
 template <> struct hb_int_max<unsigned long long>	: hb_integral_constant<unsigned long long,	ULLONG_MAX>	{};
 #define hb_int_max(T) hb_int_max<T>::value

 #if defined(__GNUC__) && __GNUC__ < 5 && !defined(__clang__)
 #define hb_is_trivially_copyable(T) __has_trivial_copy(T)
 #define hb_is_trivially_copy_assignable(T) __has_trivial_assign(T)
 #define hb_is_trivially_constructible(T) __has_trivial_constructor(T)
 #define hb_is_trivially_copy_constructible(T) __has_trivial_copy_constructor(T)
 #define hb_is_trivially_destructible(T) __has_trivial_destructor(T)
 #else
 #define hb_is_trivially_copyable(T) std::is_trivially_copyable<T>::value
 #define hb_is_trivially_copy_assignable(T) std::is_trivially_copy_assignable<T>::value
 #define hb_is_trivially_constructible(T) std::is_trivially_constructible<T>::value
 #define hb_is_trivially_copy_constructible(T) std::is_trivially_copy_constructible<T>::value
 #define hb_is_trivially_destructible(T) std::is_trivially_destructible<T>::value
 #endif

 /* Class traits. */

 #define HB_DELETE_COPY_ASSIGN(TypeName) \
   TypeName(const TypeName&) = delete; \
   void operator=(const TypeName&) = delete
 #define HB_DELETE_CREATE_COPY_ASSIGN(TypeName) \
   TypeName() = delete; \
   TypeName(const TypeName&) = delete; \
   void operator=(const TypeName&) = delete

 /* hb_unwrap_type (T)
  * If T has no T::type, returns T. Otherwise calls itself on T::type recursively.
  */

 template <typename T, typename>
 struct _hb_unwrap_type : hb_type_identity_t<T> {};
 template <typename T>
 struct _hb_unwrap_type<T, hb_void_t<typename T::type>> : _hb_unwrap_type<typename T::type, void> {};
 template <typename T>
 using hb_unwrap_type = _hb_unwrap_type<T, void>;
 #define hb_unwrap_type(T) typename hb_unwrap_type<T>::type

 #endif /* HB_META_HH */
	/*
	* Copyright © 2018 Google, Inc.
	*
	* This is part of HarfBuzz, a text shaping library.
	*
	* Permission is hereby granted, without written agreement and without
	* license or royalty fees, to use, copy, modify, and distribute this
	* software and its documentation for any purpose, provided that the
	* above copyright notice and the following two paragraphs appear in
	* all copies of this software.
	*
	* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
	* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
	* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
	* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
	* DAMAGE.
	*
	* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
	* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
	* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
	* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
	* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
	*
	* Google Author(s): Behdad Esfahbod
	*/

	#ifndef HB_META_HH
	#define HB_META_HH

	#include "hb.hh"

	#include <memory>
	#include <type_traits>
	#include <utility>


	/*
	* C++ template meta-programming & fundamentals used with them.
	*/

	/* Void! For when we need a expression-type of void. */
	struct hb_empty_t {};

	/* https://en.cppreference.com/w/cpp/types/void_t */
	template<typename... Ts> struct _hb_void_t { typedef void type; };
	template<typename... Ts> using hb_void_t = typename _hb_void_t<Ts...>::type;

	template<typename Head, typename... Ts> struct _hb_head_t { typedef Head type; };
	template<typename... Ts> using hb_head_t = typename _hb_head_t<Ts...>::type;

	template <typename T, T v> struct hb_integral_constant { static constexpr T value = v; };
	template <bool b> using hb_bool_constant = hb_integral_constant<bool, b>;
	using hb_true_type = hb_bool_constant<true>;
	using hb_false_type = hb_bool_constant<false>;

	/* Static-assert as expression. */
	template <bool cond> struct static_assert_expr;
	template <> struct static_assert_expr<true> : hb_false_type {};
	#define static_assert_expr(C) static_assert_expr<C>::value

	/* Basic type SFINAE. */

	template <bool B, typename T = void> struct hb_enable_if {};
	template <typename T> struct hb_enable_if<true, T> { typedef T type; };
	#define hb_enable_if(Cond) typename hb_enable_if<(Cond)>::type* = nullptr
	/* Concepts/Requires alias: */
	#define hb_requires(Cond) hb_enable_if((Cond))

	template <typename T, typename T2> struct hb_is_same : hb_false_type {};
	template <typename T> struct hb_is_same<T, T> : hb_true_type {};
	#define hb_is_same(T, T2) hb_is_same<T, T2>::value

	/* Function overloading SFINAE and priority. */

	#define HB_RETURN(Ret, E) -> hb_head_t<Ret, decltype ((E))> { return (E); }
	#define HB_AUTO_RETURN(E) -> decltype ((E)) { return (E); }
	#define HB_VOID_RETURN(E) -> hb_void_t<decltype ((E))> { (E); }

	template <unsigned Pri> struct hb_priority : hb_priority<Pri - 1> {};
	template <> struct hb_priority<0> {};
	#define hb_prioritize hb_priority<16> ()

	#define HB_FUNCOBJ(x) static_const x HB_UNUSED


	template <typename T> struct hb_type_identity_t { typedef T type; };
	template <typename T> using hb_type_identity = typename hb_type_identity_t<T>::type;

	template <typename T> static inline T hb_declval ();
	#define hb_declval(T) (hb_declval<T> ())

	template <typename T> struct hb_match_const : hb_type_identity_t<T>, hb_false_type {};
	template <typename T> struct hb_match_const<const T> : hb_type_identity_t<T>, hb_true_type {};
	template <typename T> using hb_remove_const = typename hb_match_const<T>::type;

	template <typename T> struct hb_match_reference : hb_type_identity_t<T>, hb_false_type {};
	template <typename T> struct hb_match_reference<T &> : hb_type_identity_t<T>, hb_true_type {};
	template <typename T> struct hb_match_reference<T &&> : hb_type_identity_t<T>, hb_true_type {};
	template <typename T> using hb_remove_reference = typename hb_match_reference<T>::type;
	template <typename T> auto _hb_try_add_lvalue_reference (hb_priority<1>) -> hb_type_identity<T&>;
	template <typename T> auto _hb_try_add_lvalue_reference (hb_priority<0>) -> hb_type_identity<T>;
	template <typename T> using hb_add_lvalue_reference = decltype (_hb_try_add_lvalue_reference<T> (hb_prioritize));
	template <typename T> auto _hb_try_add_rvalue_reference (hb_priority<1>) -> hb_type_identity<T&&>;
	template <typename T> auto _hb_try_add_rvalue_reference (hb_priority<0>) -> hb_type_identity<T>;
	template <typename T> using hb_add_rvalue_reference = decltype (_hb_try_add_rvalue_reference<T> (hb_prioritize));

	template <typename T> struct hb_match_pointer : hb_type_identity_t<T>, hb_false_type {};
	template <typename T> struct hb_match_pointer<T *> : hb_type_identity_t<T>, hb_true_type {};
	template <typename T> using hb_remove_pointer = typename hb_match_pointer<T>::type;
	template <typename T> auto _hb_try_add_pointer (hb_priority<1>) -> hb_type_identity<hb_remove_reference<T>*>;
	template <typename T> auto _hb_try_add_pointer (hb_priority<1>) -> hb_type_identity<T>;
	template <typename T> using hb_add_pointer = decltype (_hb_try_add_pointer<T> (hb_prioritize));


	template <typename T> using hb_decay = typename std::decay<T>::type;

	#define hb_is_convertible(From,To) std::is_convertible<From, To>::value

	template <typename From, typename To>
	using hb_is_cr_convertible = hb_bool_constant<
	hb_is_same (hb_decay<From>, hb_decay<To>) &&
	(!std::is_const<From>::value \|\| std::is_const<To>::value) &&
	(!std::is_reference<To>::value \|\| std::is_const<To>::value \|\| std::is_reference<To>::value)
	>;
	#define hb_is_cr_convertible(From,To) hb_is_cr_convertible<From, To>::value


	struct
	{
	template <typename T> constexpr auto
	operator () (T&& v) const HB_AUTO_RETURN (std::forward<T> (v))

	template <typename T> constexpr auto
	operator () (T v) const HB_AUTO_RETURN (v)

	template <typename T> constexpr auto
	operator () (const hb::shared_ptr<T>& v) const HB_AUTO_RETURN (*v)

	template <typename T> constexpr auto
	operator () (hb::shared_ptr<T>& v) const HB_AUTO_RETURN (*v)

	template <typename T> constexpr auto
	operator () (const hb::unique_ptr<T>& v) const HB_AUTO_RETURN (*v)

	template <typename T> constexpr auto
	operator () (hb::unique_ptr<T>& v) const HB_AUTO_RETURN (*v)
	}
	HB_FUNCOBJ (hb_deref);

	template <typename T>
	struct hb_reference_wrapper
	{
	hb_reference_wrapper (T v) : v (v) {}
	bool operator == (const hb_reference_wrapper& o) const { return v == o.v; }
	bool operator != (const hb_reference_wrapper& o) const { return v != o.v; }
	operator T& () { return v; }
	T& get () { return v; }
	T v;
	};
	template <typename T>
	struct hb_reference_wrapper<T&>
	{
	hb_reference_wrapper (T& v) : v (std::addressof (v)) {}
	bool operator == (const hb_reference_wrapper& o) const { return v == o.v; }
	bool operator != (const hb_reference_wrapper& o) const { return v != o.v; }
	operator T& () { return *v; }
	T& get () { return *v; }
	T* v;
	};


	/* Type traits */

	template <typename T> struct hb_int_min;
	template <> struct hb_int_min<char> : hb_integral_constant<char, CHAR_MIN> {};
	template <> struct hb_int_min<signed char> : hb_integral_constant<signed char, SCHAR_MIN> {};
	template <> struct hb_int_min<unsigned char> : hb_integral_constant<unsigned char, 0> {};
	template <> struct hb_int_min<signed short> : hb_integral_constant<signed short, SHRT_MIN> {};
	template <> struct hb_int_min<unsigned short> : hb_integral_constant<unsigned short, 0> {};
	template <> struct hb_int_min<signed int> : hb_integral_constant<signed int, INT_MIN> {};
	template <> struct hb_int_min<unsigned int> : hb_integral_constant<unsigned int, 0> {};
	template <> struct hb_int_min<signed long> : hb_integral_constant<signed long, LONG_MIN> {};
	template <> struct hb_int_min<unsigned long> : hb_integral_constant<unsigned long, 0> {};
	template <> struct hb_int_min<signed long long> : hb_integral_constant<signed long long, LLONG_MIN> {};
	template <> struct hb_int_min<unsigned long long> : hb_integral_constant<unsigned long long, 0> {};
	template <typename T> struct hb_int_min<T > : hb_integral_constant<T , nullptr> {};
	#define hb_int_min(T) hb_int_min<T>::value
	template <typename T> struct hb_int_max;
	template <> struct hb_int_max<char> : hb_integral_constant<char, CHAR_MAX> {};
	template <> struct hb_int_max<signed char> : hb_integral_constant<signed char, SCHAR_MAX> {};
	template <> struct hb_int_max<unsigned char> : hb_integral_constant<unsigned char, UCHAR_MAX> {};
	template <> struct hb_int_max<signed short> : hb_integral_constant<signed short, SHRT_MAX> {};
	template <> struct hb_int_max<unsigned short> : hb_integral_constant<unsigned short, USHRT_MAX> {};
	template <> struct hb_int_max<signed int> : hb_integral_constant<signed int, INT_MAX> {};
	template <> struct hb_int_max<unsigned int> : hb_integral_constant<unsigned int, UINT_MAX> {};
	template <> struct hb_int_max<signed long> : hb_integral_constant<signed long, LONG_MAX> {};
	template <> struct hb_int_max<unsigned long> : hb_integral_constant<unsigned long, ULONG_MAX> {};
	template <> struct hb_int_max<signed long long> : hb_integral_constant<signed long long, LLONG_MAX> {};
	template <> struct hb_int_max<unsigned long long> : hb_integral_constant<unsigned long long, ULLONG_MAX> {};
	#define hb_int_max(T) hb_int_max<T>::value

	#if defined(__GNUC__) && __GNUC__ < 5 && !defined(__clang__)
	#define hb_is_trivially_copyable(T) __has_trivial_copy(T)
	#define hb_is_trivially_copy_assignable(T) __has_trivial_assign(T)
	#define hb_is_trivially_constructible(T) __has_trivial_constructor(T)
	#define hb_is_trivially_copy_constructible(T) __has_trivial_copy_constructor(T)
	#define hb_is_trivially_destructible(T) __has_trivial_destructor(T)
	#else
	#define hb_is_trivially_copyable(T) std::is_trivially_copyable<T>::value
	#define hb_is_trivially_copy_assignable(T) std::is_trivially_copy_assignable<T>::value
	#define hb_is_trivially_constructible(T) std::is_trivially_constructible<T>::value
	#define hb_is_trivially_copy_constructible(T) std::is_trivially_copy_constructible<T>::value
	#define hb_is_trivially_destructible(T) std::is_trivially_destructible<T>::value
	#endif

	/* Class traits. */

	#define HB_DELETE_COPY_ASSIGN(TypeName) \
	TypeName(const TypeName&) = delete; \
	void operator=(const TypeName&) = delete
	#define HB_DELETE_CREATE_COPY_ASSIGN(TypeName) \
	TypeName() = delete; \
	TypeName(const TypeName&) = delete; \
	void operator=(const TypeName&) = delete

	/* hb_unwrap_type (T)
	* If T has no T::type, returns T. Otherwise calls itself on T::type recursively.
	*/

	template <typename T, typename>
	struct _hb_unwrap_type : hb_type_identity_t<T> {};
	template <typename T>
	struct _hb_unwrap_type<T, hb_void_t<typename T::type>> : _hb_unwrap_type<typename T::type, void> {};
	template <typename T>
	using hb_unwrap_type = _hb_unwrap_type<T, void>;
	#define hb_unwrap_type(T) typename hb_unwrap_type<T>::type

	#endif /* HB_META_HH */