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| -rw-r--r-- | gfx/harfbuzz/src/hb-meta.hh | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-meta.hh b/gfx/harfbuzz/src/hb-meta.hh new file mode 100644 index 0000000000..31aa7fa6f1 --- /dev/null +++ b/gfx/harfbuzz/src/hb-meta.hh @@ -0,0 +1,238 @@ +/* + * 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 */ |