1 files changed, 248 insertions, 0 deletions
diff --git a/asl/base/meta.hpp b/asl/base/meta.hpp
new file mode 100644
index 0000000..ce17420
--- /dev/null
+++ b/asl/base/meta.hpp
@@ -0,0 +1,248 @@
+#pragma once
+
+#include "asl/base/integers.hpp"
+
+namespace asl {
+
+struct source_location
+{
+    const char* file;
+    int         line;
+
+    explicit source_location(
+        const char* file_ = __builtin_FILE(),
+        int line_ = __builtin_LINE())
+        : file{file_}
+        , line{line_}
+    {}
+};
+
+struct empty {};
+
+template<typename T> struct id { using type = T; };
+
+template<typename... Args> static constexpr isize_t types_count = sizeof...(Args);
+
+template<typename T, T kValue> struct integral_constant { static constexpr T value = kValue; };
+template<bool B> using bool_constant = integral_constant<bool, B>;
+
+using true_type  = bool_constant<true>;
+using false_type = bool_constant<false>;
+
+template<bool kSelect, typename U, typename V> struct _select_helper             { using type = V; };
+template<typename U, typename V>               struct _select_helper<true, U, V> { using type = U; };
+
+template<bool kSelect, typename U, typename V> using select_t = _select_helper<kSelect, U, V>::type;
+
+template<typename U, typename V> struct _same_as_helper       : false_type {};
+template<typename T>             struct _same_as_helper<T, T> : true_type {};
+
+template<typename U, typename V> concept same_as = _same_as_helper<U, V>::value && _same_as_helper<V, U>::value;
+
+template<typename T> auto _as_lref_helper(int) -> id<T&>;
+template<typename T> auto _as_lref_helper(...) -> id<T>;
+
+template<typename T> auto _as_rref_helper(int) -> id<T&&>;
+template<typename T> auto _as_rref_helper(...) -> id<T>;
+
+template<typename T> using as_lref_t = decltype(_as_lref_helper<T>(0))::type;
+template<typename T> using as_rref_t = decltype(_as_rref_helper<T>(0))::type;
+
+template<typename T> consteval as_rref_t<T> declval() {}
+
+template<typename T> struct _un_ref_t      { using type = T; };
+template<typename T> struct _un_ref_t<T&>  { using type = T; };
+template<typename T> struct _un_ref_t<T&&> { using type = T; };
+
+template<typename T> using un_ref_t = _un_ref_t<T>::type;
+
+template<typename T, typename... Args> concept constructible_from = __is_constructible(T, Args...);
+
+template<typename T> concept default_constructible = constructible_from<T>;
+template<typename T> concept copy_constructible    = constructible_from<T, as_lref_t<const T>>;
+template<typename T> concept move_constructible    = constructible_from<T, as_rref_t<T>>;
+
+template<typename T, typename... Args> concept trivially_constructible_from = __is_trivially_constructible(T, Args...);
+
+template<typename T> concept trivially_default_constructible = trivially_constructible_from<T>;
+template<typename T> concept trivially_copy_constructible    = trivially_constructible_from<T, as_lref_t<const T>>;
+template<typename T> concept trivially_move_constructible    = trivially_constructible_from<T, as_rref_t<T>>;
+
+template<typename T, typename... Args> concept assignable_from = __is_assignable(T, Args...);
+
+template<typename T> concept copy_assignable = assignable_from<as_lref_t<T>, as_lref_t<const T>>;
+template<typename T> concept move_assignable = assignable_from<as_lref_t<T>, as_rref_t<T>>;
+
+template<typename T, typename... Args> concept trivially_assignable_from = __is_trivially_assignable(T, Args...);
+
+template<typename T> concept trivially_copy_assignable = trivially_assignable_from<as_lref_t<T>, as_lref_t<const T>>;
+template<typename T> concept trivially_move_assignable = trivially_assignable_from<as_lref_t<T>, as_rref_t<T>>;
+
+template<typename T> concept trivially_destructible = __is_trivially_destructible(T);
+
+template<typename T> concept copyable = copy_constructible<T> && copy_assignable<T>;
+template<typename T> concept moveable = move_constructible<T> && move_assignable<T>;
+
+template<typename To, typename From>
+concept convertible_from = __is_convertible(From, To);
+
+template<typename Derived, class Base>
+concept derived_from = __is_class(Derived) && __is_class(Base) && convertible_from<const volatile Base*, const volatile Derived*>;
+
+using nullptr_t = decltype(nullptr);
+
+template<typename T> struct _un_const_helper          { using type = T; };
+template<typename T> struct _un_const_helper<const T> { using type = T; };
+
+template<typename T> using un_const_t = _un_const_helper<T>::type;
+
+template<typename T> struct _is_const_helper          : false_type {};
+template<typename T> struct _is_const_helper<const T> : true_type {};
+
+template<typename T> concept is_const = _is_const_helper<T>::value;
+
+template<typename T> struct _un_volatile_helper             { using type = T; };
+template<typename T> struct _un_volatile_helper<volatile T> { using type = T; };
+
+template<typename T> using un_volatile_t = _un_volatile_helper<T>::type;
+
+template<typename T> using un_cv_t = un_volatile_t<un_const_t<T>>;
+
+template<typename T> using un_cvref_t = un_ref_t<un_cv_t<T>>;
+
+template<typename T> concept is_void = same_as<void, un_cv_t<T>>;
+
+template<typename T> struct _is_ref_helper      { static constexpr bool l = false; static constexpr bool r = false; };
+template<typename T> struct _is_ref_helper<T&>  { static constexpr bool l = true;  static constexpr bool r = false; };
+template<typename T> struct _is_ref_helper<T&&> { static constexpr bool l = false; static constexpr bool r = true;  };
+
+template<typename T> concept is_ref = _is_ref_helper<T>::l || _is_ref_helper<T>::r;
+template<typename T> concept is_rref = _is_ref_helper<T>::r;
+template<typename T> concept is_lref = _is_ref_helper<T>::l;
+
+template<typename T> struct _is_ptr_helper     : false_type {};
+template<typename T> struct _is_ptr_helper<T*> : true_type {};
+
+template<typename T> concept is_ptr = _is_ptr_helper<un_cv_t<T>>::value;
+
+template<typename T> struct _tame_helper { using type = T; };
+
+#define TAME_HELPER_IMPL(TRAILING)                                  \
+    template<typename R, typename... Args>                          \
+    struct _tame_helper<R(Args...) TRAILING> { using type = R(Args...); }
+
+TAME_HELPER_IMPL();
+TAME_HELPER_IMPL(&);
+TAME_HELPER_IMPL(&&);
+TAME_HELPER_IMPL(const);
+TAME_HELPER_IMPL(const &);
+TAME_HELPER_IMPL(const &&);
+TAME_HELPER_IMPL(volatile);
+TAME_HELPER_IMPL(volatile &);
+TAME_HELPER_IMPL(volatile &&);
+TAME_HELPER_IMPL(const volatile);
+TAME_HELPER_IMPL(const volatile &);
+TAME_HELPER_IMPL(const volatile &&);
+TAME_HELPER_IMPL(noexcept);
+TAME_HELPER_IMPL(& noexcept);
+TAME_HELPER_IMPL(&& noexcept);
+TAME_HELPER_IMPL(const noexcept);
+TAME_HELPER_IMPL(const & noexcept);
+TAME_HELPER_IMPL(const && noexcept);
+TAME_HELPER_IMPL(volatile noexcept);
+TAME_HELPER_IMPL(volatile & noexcept);
+TAME_HELPER_IMPL(volatile && noexcept);
+TAME_HELPER_IMPL(const volatile noexcept);
+TAME_HELPER_IMPL(const volatile & noexcept);
+TAME_HELPER_IMPL(const volatile && noexcept);
+
+#undef TAME_HELPER_IMPL
+
+template<typename T> using tame_t = _tame_helper<T>::type;
+
+template<typename T>                   struct _is_func_helper             : false_type {};
+template<typename R, typename... Args> struct _is_func_helper<R(Args...)> : true_type {};
+
+template<typename T> concept is_func = _is_func_helper<tame_t<T>>::value;
+
+template<typename T> concept is_object = !is_void<T> && !is_ref<T> && !is_func<T>;
+
+template<typename T>        struct _is_array_helper       : false_type {};
+template<typename T>        struct _is_array_helper<T[]>  : true_type  {};
+template<typename T, int N> struct _is_array_helper<T[N]> : true_type  {};
+
+template<typename T> concept is_array = _is_array_helper<T>::value;
+
+template<typename T> struct _is_floating_point_helper         : false_type {};
+template<>           struct _is_floating_point_helper<float>  : true_type  {};
+template<>           struct _is_floating_point_helper<double> : true_type  {};
+
+template<typename T> concept is_floating_point = _is_floating_point_helper<un_cv_t<T>>::value;
+
+template<typename T> struct _is_integer_helper           : false_type {};
+template<>           struct _is_integer_helper<int8_t>   : true_type  {};
+template<>           struct _is_integer_helper<int16_t>  : true_type  {};
+template<>           struct _is_integer_helper<int32_t>  : true_type  {};
+template<>           struct _is_integer_helper<int64_t>  : true_type  {};
+template<>           struct _is_integer_helper<uint8_t>  : true_type  {};
+template<>           struct _is_integer_helper<uint16_t> : true_type  {};
+template<>           struct _is_integer_helper<uint32_t> : true_type  {};
+template<>           struct _is_integer_helper<uint64_t> : true_type  {};
+
+template<typename T> concept is_integer = _is_integer_helper<un_cv_t<T>>::value;
+
+template<typename T> concept is_enum = __is_enum(T);
+
+template<typename T> struct is_uniquely_represented : false_type {};
+template<is_integer T> struct is_uniquely_represented<T> : true_type {};
+template<is_enum T> struct is_uniquely_represented<T> : true_type {};
+template<> struct is_uniquely_represented<uint128_t> : true_type {};
+template<> struct is_uniquely_represented<byte> : true_type {};
+
+template<typename T> concept uniquely_represented = is_uniquely_represented<un_cv_t<T>>::value;
+
+template<typename T, typename U>
+concept equality_comparable_with = requires (const un_cvref_t<T>& a, const un_cvref_t<U>& b)
+{
+    { a == b } -> same_as<bool>;
+    { b == a } -> same_as<bool>;
+    { a != b } -> same_as<bool>;
+    { b != a } -> same_as<bool>;
+};
+
+template<typename T> concept equality_comparable = equality_comparable_with<T, T>;
+
+struct niche_t {};
+
+template<typename T>
+concept has_niche = constructible_from<T, niche_t> && equality_comparable_with<T, niche_t>;
+
+template<typename T>
+concept is_niche = same_as<un_cvref_t<T>, niche_t>;
+
+template<typename T, typename U>
+concept _derefs_with_indirection_as = requires(T& t)
+{
+    *t;
+    requires convertible_from<U&, decltype(*t)>;
+};
+
+template<typename T, typename U>
+concept _derefs_reference_as = is_ref<T> && convertible_from<U&, T>;
+
+template<typename T, typename U>
+concept _derefs_value_as = !is_ref<T> && convertible_from<U&, T&>;
+
+template<typename U, _derefs_with_indirection_as<U> T>
+constexpr U& deref(T&& t) { return static_cast<U&>(*t); }
+
+template<typename U, _derefs_reference_as<U> T>
+constexpr U& deref(T&& t) { return static_cast<U&>(t); }
+
+template<typename U, _derefs_value_as<U> T>
+constexpr U& deref(T&& t) { return static_cast<U&>(t); }
+
+template<typename T, typename U>
+concept derefs_as = _derefs_with_indirection_as<T, U> || _derefs_reference_as<T, U> || _derefs_value_as<T, U>;
+
+} // namespace asl