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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));
/* 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
/* 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 */
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