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+/*
+ * 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 () const { return v; }
+ T get () const { 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& () const { return *v; }
+ T& get () const { 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 */