| /* |
| * 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)); |
| |
| |
| /* TODO Add feature-parity to std::decay. */ |
| template <typename T> using hb_decay = hb_remove_const<hb_remove_reference<T>>; |
| |
| #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) |
| } |
| 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 |
| #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 */ |