AuROXTL/Include/auROXTL/auTemplateMeta.hpp

/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: auTemplateMeta.hpp
    Date: 2022-2-1
    Author: Reece
    Note: most of this code assumes C++17 or greater
***/
#pragma once

template <bool v>
struct AuBoolType
{
    static AUROXTL_CONSTEXPR bool value = v;
    using value_type = bool;
    using type = AuBoolType;

    AUROXTL_CONSTEXPR operator value_type() const noexcept
    {
        return value;
    }

    AUROXTL_CONSTEXPR value_type operator()() const noexcept
    {
        return value;
    }
};

using AuFalseType = AuBoolType<false>;
using AuTrueType = AuBoolType<true>;

#include "auTemplateMetaIsFunction.hpp"

template <class T>
using AuToValueType_t = typename T::value_type;

template <class T>
using AuToElementType_t = typename T::element_type;

template <class T>
using AuToIterator_t = typename T::iterator;

template <typename T>
static AuToIterator_t<T> AuToIterator(const T &a); // intended use case:  `decltype(AuToIterator(myHashMap)) itr;`
template <typename T>
static AuToElementType_t<T> AuToElementType(const T &a);

template <typename T>
static AuToValueType_t<T> AuToValueType(const T &a);

template <class T, class U>
struct AuIsSame : AuFalseType
{};

template <class T>
struct AuIsSame<T, T> : AuTrueType
{};

template <class T, class U>
inline AUROXTL_CONSTEXPR bool AuIsSame_v = AuIsSame<T, U>::value;

template <class>
inline AUROXTL_CONSTEXPR bool AuIsConst_v = false;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsConst_v<const T> = true;

namespace _audetail
{
    template <class T>
    AuBoolType<!__is_union(T)> IsClass(int T:: *);

    template <class>
    AuFalseType IsClass(...);

    template <class B>
    AuTrueType TestIsPtrConvertible(const volatile B *);
    template <class>
    AuFalseType TestIsPtrConvertible(const volatile void *);

    template <class, typename>
    auto TestIsBaseOf(...) -> AuTrueType;

    template <class B, typename D>
    auto TestIsBaseOf(int) -> decltype(TestIsPtrConvertible<B>(static_cast<D *>(nullptr)));

    // yoinked: https://stackoverflow.com/a/40867906
    template<typename Func, typename...Params> static auto IsCallable(int) -> decltype((void)AuDeclVal<Func>()(AuDeclVal<Params>()...), AuTrueType {});
    template<typename Func, typename...Params> static AuFalseType IsCallable(...);
}

template <class T>
struct AuIsClass : decltype(_audetail::IsClass<T>(nullptr))
{};

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsClass_v = AuIsClass<T>::value;

template <class Base, typename Derived>
struct AuIsBaseOf :
    AuBoolType<
        AuIsClass_v<Base> &&
        AuIsClass_v<Derived> &&
        decltype(_audetail::TestIsBaseOf<Base, Derived>(0))::value
    >
{};

template <class Base, typename Derived>
inline AUROXTL_CONSTEXPR bool AuIsBaseOf_v = AuIsBaseOf<Base, Derived>::value;

template <class>
inline AUROXTL_CONSTEXPR bool AuIsPointer_v = false;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsPointer_v<T *> = true;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsPointer_v<T *const> = true;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsPointer_v<T *volatile> = true;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsPointer_v<T *const volatile> = true;

template <class>
inline AUROXTL_CONSTEXPR bool AuIsReference_v = false;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsReference_v<T &> = true;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsReference_v<T &&> = true;

template <class>
inline AUROXTL_CONSTEXPR bool AuIsLValueReference_v = false;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsLValueReference_v<T &> = true;

template <class>
inline AUROXTL_CONSTEXPR bool AuIsRValueReference_v = false;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsRValueReference_v<T &&> = true;

template <class T>
struct AuRemovePointer
{
    typedef T type;
};

template <class T>
struct AuRemovePointer<T *>
{
    typedef T type;
};

template <class T>
struct AuRemovePointer<T *const>
{
    typedef T type;
};

template <class T>
struct AuRemovePointer<T *volatile>
{
    typedef T type;
};

template <class T>
struct AuRemovePointer<T *const volatile>
{
    typedef T type;
};

template <class T>
using AuRemovePointer_t = typename AuRemovePointer<T>::type;

template <class T>
using AuIsVoid = AuIsSame<void, T>;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsVoid_v = AuIsVoid<T>::value;

template <class T>
struct AuRemoveReference
{
    using type = T;
};

template <class T>
struct AuRemoveReference<T &>
{
    using type = T;
};

template <class T>
struct AuRemoveReference<T &&>
{
    using type = T;
};

template <class T>
using AuRemoveReference_t = typename AuRemoveReference<T>::type;

template <class T>
struct AuRemoveConst
{
    typedef T type;
};

template <class T>
struct AuRemoveConst<const T>
{
    typedef T type;
};

template <class T>
using AuRemoveConst_t = typename AuRemoveConst<T>::type;

template <class T>
struct AuRemoveVolatile
{
    typedef T type;
};

template <class T>
struct AuRemoveVolatile<volatile T>
{
    typedef T type;
};

template <class T>
using AuRemoveVolatile_t = typename AuRemoveVolatile<T>::type;

template <bool Test, class T = void>
struct AuEnableIf
{};

template <class T>
struct AuEnableIf<true, T>
{
    using type = T;
};

template <class T>
struct AuAddPointer
{
    using type = AuRemoveReference_t<T> *;
};

template <class T>
using AuAddPointer_t = typename AuAddPointer<T>::type;

template <class T>
struct AuAddLReference
{
    using type = AuRemoveReference_t<T> &;
};

template <class T>
using AuAddLReference_t = typename AuAddLReference<T>::type;

template <class T>
struct AuAddRReference
{
    using type = AuRemoveReference_t<T> &&;
};

template <class T>
using AuAddRReference_t = typename AuAddRReference<T>::type;

template <class T>
T &&AuDeclVal();

template <class T>
struct AuAddConst
{
    using type = const T;
};

template <class T>
using AuAddConst_t = typename AuAddConst<T>::type;

template <class T>
using AuRemoveCV_t = AuRemoveConst_t<AuRemoveReference_t<T>>;

template <class T>
struct AuRemoveExtent
{
    using type = T;
};

template <class T>
struct AuRemoveExtent<T[]>
{
    using type = T;
};

template <class T, AuUInt Len>
struct AuRemoveExtent<T[Len]>
{
    using type = T;
};

template <class T>
using AuRemoveExtent_t = typename AuRemoveExtent<T>::type;

template <class ... Ts>
using AuVoid_t = void;

template <class>
AUROXTL_CONSTEXPR inline bool AuIsArray_v = false;

template <class T, size_t Len>
inline AUROXTL_CONSTEXPR bool AuIsArray_v<T[Len]> = true;

template <class T>
inline AUROXTL_CONSTEXPR bool AuIsArray_v<T[]> = true;

template <bool Test, class T = void>
using AuEnableIf_t = typename AuEnableIf<Test, T>::type;

#if !defined(AURORA_COMPILER_CLANG) && !defined(AURORA_COMPILER_MSVC)
template <class T, class ... Args>
struct AuIsConstructible
{
    template <class C, class ... Args2> static AUROXTL_CONSTEXPR AuTrueType  Test(decltype(::new C(AuDeclVal<Args2>()...)));
    template <class C, class ... Args2> static AUROXTL_CONSTEXPR AuFalseType Test(...);
    using type = decltype(Test<T, Args...>(0));
};

template <class T, class ... Args>
using AuIsConstructible_t = typename AuIsConstructible<T, Args ...>::type;

#else
template <class T, class ... Args>
struct AuIsConstructible : AuBoolType<__is_constructible(T, Args...)>
{
};

template <class T, class ... Args>
using AuIsConstructible_t = typename AuIsConstructible<T, Args ...>::type;

#endif

template <class T, class ... Args>
inline AUROXTL_CONSTEXPR bool AuIsConstructible_v = AuIsConstructible<T, Args ...>::type::value;

template <bool Test, class T, class T2>
struct AuConditional
{
    using type = T;
};

template <class T, class T2>
struct AuConditional<false, T, T2>
{
    using type = T2;
};

template <bool Test, class T, class T2>
using AuConditional_t = typename AuConditional<Test, T, T2>::type;

template <class T>
using AuDecay_t = AuConditional_t<
    AuIsArray_v<T>,
    AuAddPointer_t<AuRemoveExtent_t<T>>,
    AuConditional_t<
        AuIsFunction_v<T>,
        AuAddPointer_t<T>,
        AuRemoveCV_t<T>
    >
>;

template <class T>
struct AuDecay
{
    using type = AuDecay_t<T>;
};

template <template <class...> class Base, typename Derived>
struct AuIsBaseOfTemplateImpl
{
    template <class... Ts>
    static AUROXTL_CONSTEXPR AuTrueType  Test(const Base<Ts...> *);
    static AUROXTL_CONSTEXPR AuFalseType Test(...);
    using type = decltype(Test(AuDeclVal<AuRemoveReference_t<Derived> *>()));
};

template <template <class...> class Base, typename Derived>
using AuIsBaseOfTemplate = typename AuIsBaseOfTemplateImpl<Base, Derived>::type;

template <template <class...> class Base, typename Derived>
inline AUROXTL_CONSTEXPR bool AuIsBaseOfTemplate_v = AuIsBaseOfTemplateImpl<Base, Derived>::type::value;

#if !defined(AURORA_ROXTL_NO_STD)

// :(
// we have a boost licensed call traits in auv8pp
#include <type_traits>

#if defined(AU_LANG_CPP_14)
    template <class T, class... Args>
    using AuResultOf_t = typename std::result_of_t<T, Args...>;
#else
    template <class T, class... Args>
    using AuResultOf_t = typename std::invoke_result_t<T, Args...>;
#endif

#endif

template <class Func, class ...Params>
struct AuCallable : decltype(_audetail::IsCallable<Func, Params...>(0))
{
};

template <class F, class... Args>
AUROXTL_CONSTEXPR auto AuIsCallable_v = AuCallable<F, Args...>::value;

#include "auCopyMoveUtils.hpp"

template <AuUInt uSize, class T>
struct AU_ALIGN(uSize)
    AuAlignTo : T
{
    inline AuAlignTo() : T()
    {

    }

    inline AuAlignTo(T &&t) : T(AuForward<T&&>(t))
    {

    }

    inline AuAlignTo(const T &t) : T(t)
    {

    }
};

template <class Ret_t, class T, class ...Args>
static auto AuGetAmbiguousMethod2(Ret_t(T :: *a)(Args...))
{
    return a;
}


// According to MSVC: "only function types and reference types can't be const qualified"

#if 0
    // MSVCs implementation is as follows:
    // Our implementation is found in ./auTemplateMetaIsFunction.hpp
    template <class T>
    AUROXTL_CONSTEXPR bool AuIsFunction_v = !AuIsConst_v<const T> && !AuIsReference_v<T>;

    template <class T>
    struct AuIsFunction : AuBoolType<AuIsFunction_v<T>>
    { };
#endif

// Continuing on: this is how MSVC defines std::is_object in contrast to std::is_function
template <class T>
AUROXTL_CONSTEXPR bool AuIsObject_v = AuIsConst_v<const T> && !AuIsVoid_v<T>;

template <class T>
struct AuIsObject : AuBoolType<AuIsObject_v<T>>
{ };

#if defined(AURORA_COMPILER_CLANG)
    template <class T>
    AUROXTL_CONSTEXPR bool AuIsMemberFunctionPointer_v = __is_member_function_pointer(T);

    template <class T>
    AUROXTL_CONSTEXPR bool AuIsMemberPointer_v = __is_member_pointer(T);


#elif defined(AURORA_COMPILER_MSVC) || defined(AURORA_ROXTL_NO_NO_STD)
    template <class T>
    AUROXTL_CONSTEXPR bool AuIsMemberFunctionPointer_v = std::is_member_function_pointer_v<T>;

    template <class T>
    AUROXTL_CONSTEXPR bool AuIsMemberPointer_v = std::is_member_object_pointer_v<T> || AuIsMemberFunctionPointer_v<T>;
#endif

// I dont think I can easily implement these in templates
// For the sake of syntax sugar, these will be macros for now
#define AuGetAmbiguousMethod(Ret_t, Args, T, Method) AuGetAmbiguousMethod2<Ret_t, T, AU_BRACKET_SCOPE Args >(&T::Method)

#define AuGetAmbiguousMethod_v AuGetAmbiguousMethod

namespace _audetail
{
    // yoinking https://en.cppreference.com/w/cpp/types/common_type
    template<class...>
    struct common_type
    { };

    template<class T>
    struct common_type<T> : common_type<T, T>
    { };

    namespace ctdetail
    {
        template<class...>
        using void_t = void;
        
        template<class T1, class T2>
        using conditional_result_t = decltype(false ? AuDeclVal<T1>() : AuDeclVal<T2>());
        
        template<class, class, class = void>
        struct decay_conditional_result
        { };

        template<class T1, class T2>
        struct decay_conditional_result<T1, T2, void_t<conditional_result_t<T1, T2>>>
            : AuDecay<conditional_result_t<T1, T2>>
        { };

        template<class T1, class T2, class = void>
        struct common_type_2_impl : decay_conditional_result<const T1 &, const T2 &>
        { };

        template<class T1, class T2>
        struct common_type_2_impl<T1, T2, void_t<conditional_result_t<T1, T2>>>
            : decay_conditional_result<T1, T2>
        { };
    }

    template<class T1, class T2>
    struct common_type<T1, T2>
        : AuConditional<AuIsSame_v<T1, AuDecay_t<T1>> && AuIsSame_v<T2, AuDecay_t<T2>>,
                                   ctdetail::common_type_2_impl<T1, T2>,
                                   common_type<AuDecay_t<T1>, AuDecay_t<T2>>>::type 
    {};

    namespace ctdetail
    {
        template<class AlwaysVoid, class T1, class T2, class...R>
        struct common_type_multi_impl
        { };
        template<class T1, class T2, class...R>
        struct common_type_multi_impl<void_t<typename common_type<T1, T2>::type>, T1, T2, R...>
            : common_type<typename common_type<T1, T2>::type, R...>
        { };
    }

    // yoinking: https://en.cppreference.com/w/cpp/utility/functional/invoke

    template<class>
    AUROXTL_CONSTEXPR bool is_reference_wrapper_v = false;

#if !defined(AURORA_ROXTL_NO_STD)
    template<class U>
    AUROXTL_CONSTEXPR bool is_reference_wrapper_v<std::reference_wrapper<U>> = true;
#endif

#if !defined(AU_LANG_CPP_14)
    template<class T>
    using remove_cvref_t = AuRemoveCV_t<AuRemoveReference_t<T>>;

    template<class C, class Pointed, class Object, class... Args>
    AUROXTL_CONSTEXPR decltype(auto) invoke_memptr(Pointed C:: *member, Object &&object,
                                           Args&&... args)
    {
        using object_t = remove_cvref_t<Object>;

        AUROXTL_CONSTEXPR bool bIsMemberFunction = AuIsFunction_v<Pointed>;
        AUROXTL_CONSTEXPR bool bIsWrapped = is_reference_wrapper_v<object_t>;
        AUROXTL_CONSTEXPR bool bIsDerivedObject = AuIsSame_v<C, object_t> || AuIsBaseOf_v<C, object_t>;

        if AUROXTL_CONSTEXPR (bIsMemberFunction)
        {
            if AUROXTL_CONSTEXPR (bIsDerivedObject)
            {
                return (AuForward<Object>(object).*member)(AuForward<Args>(args)...);
            }
            else if AUROXTL_CONSTEXPR (bIsWrapped)
            {
                return (object.get().*member)(AuForward<Args>(args)...);
            }
            else
            {
                return ((*AuForward<Object>(object)).*member)(AuForward<Args>(args)...);
            }
        }
        else
        {
            static_assert(AuIsObject_v<Pointed> && sizeof...(args) == 0);

            if AUROXTL_CONSTEXPR (bIsDerivedObject)
            {
                return AuForward<Object>(object).*member;
            }
            else if AUROXTL_CONSTEXPR (bIsWrapped)
            {
                return object.get().*member;
            }
            else
            {
                return (*AuForward<Object>(object)).*member;
            }
        }
    }
#endif

    template<class T>
    auto test_returnable(int) -> decltype(void(static_cast<T(*)()>(nullptr)), AuTrueType {});

    template<class>
    auto test_returnable(...) -> AuFalseType;

    template<class From, class To>
    auto test_implicitly_convertible(int) -> decltype(void(AuDeclType<void(&)(To)>()(AuDeclType<From>())), AuTrueType {});

    template<class, class>
    auto test_implicitly_convertible(...) -> AuFalseType;
}

template <class T, class T2>
using AuCommonType = typename _audetail::common_type<T, T2>;

template <class T, class T2>
using AuCommonType_t = typename _audetail::common_type<T, T2>::type;

#if !defined(AU_LANG_CPP_14)

    template <class F, class... Args>
    AUROXTL_CONSTEXPR AuResultOf_t<F, Args...> AuInvoke(F &&f, Args&&... args) 
    {
        if AUROXTL_CONSTEXPR (AuIsMemberPointer_v<_audetail::remove_cvref_t<F>>)
        {
            return _audetail::invoke_memptr(f, AuForward<Args>(args)...);
        }
        else
        {
            return AuForward<F>(f)(AuForward<Args>(args)...);
        }
    }

#else

    template <class F, class... Args>
    AuResultOf_t<F, Args...> AuInvoke(F &&f, Args&&... args)
    {
        return AuForward<F>(std::invoke(f, AuForward<Args>(args)...));
    }

#endif


template <class T, class Z>
struct AuIsAssignable : AuBoolType<__is_assignable(T, Z)>
{ };

template <class T, class Z>
constexpr bool AuIsAssignable_v = AuIsAssignable<T, Z>::value;

template <class T>
struct AuIsCopyAssignable : AuIsAssignable<AuAddLReference_t<T>, AuAddRReference_t<const T>>
{ };

template <class T>
constexpr bool AuIsCopyAssignable_v = AuIsCopyAssignable<T>::value;

template<class T>
struct AuIsMoveAssignable : AuIsAssignable<AuAddLReference_t<T>, AuAddRReference_t<T>>
{ };

template <class T>
constexpr bool AuIsMoveAssignable_v = AuIsMoveAssignable<T>::value;

template <class T, class Z>
struct AuIsTriviallyAssignable : AuBoolType<__is_trivially_assignable(T, Z)>
{ };

template <class T, class Z>
constexpr bool AuIsTriviallyAssignable_v = AuIsTriviallyAssignable<T, Z>::value;

template<class T>
struct AuIsTriviallyCopyAssignable
    : AuIsTriviallyAssignable<AuAddLReference_t<T>, AuAddRReference_t<const T>>
{ };

template<class T>
constexpr bool AuIsTriviallyCopyAssignable_v = AuIsTriviallyCopyAssignable<T>::value;

template<class T>
struct AuIsTriviallyMoveAssignable
    : AuIsTriviallyAssignable<AuAddLReference_t<T>, AuAddRReference_t<T>>
{ };

template<class T>
constexpr bool AuIsTriviallyMoveAssignable_v = AuIsTriviallyMoveAssignable<T>::value;

template <class T>
struct AuIsMoveConstructible : AuIsConstructible<T, T>
{ };

template <class T>
constexpr bool AuIsMoveConstructible_v = AuIsMoveConstructible<T>::value;

template <class T>
struct AuIsCopyConstructible : AuIsConstructible<T, AuAddLReference_t<const T>>
{ };

template <class T>
constexpr bool AuIsCopyConstructible_v =  AuIsCopyConstructible<T>::value;

template <class T>
struct AuIsDefaultConstructible : AuIsConstructible<T>
{ };

template <class T>
constexpr bool AuIsDefaultConstructible_v = AuIsDefaultConstructible<T>::value;

template <class T>
struct AuIsTriviallyDestructible : AuBoolType<__is_trivially_destructible(T)>
{ };

template <class T>
constexpr bool AuIsTriviallyDestructible_v = AuIsTriviallyDestructible<T>::value;

//template<class From, class To>
//struct AuIsConvertible : AuBoolType<
//    (decltype(_audetail::test_returnable<To>(0))::value &&
//        decltype(_audetail::test_implicitly_convertible<From, To>(0))::value) ||
//    (AuIsVoid<From>::value && AuIsVoid<To>::value)
//>
//{ };
template<class From, class To>
struct AuIsConvertible : AuBoolType<__is_convertible_to(From, To)>
{ };

template <class T, class Z>
constexpr bool AuIsConvertible_v = AuIsConvertible<T, Z>::value;

template <class T, class Z>
struct AuIsNothrowAssignable : AuBoolType<__is_nothrow_assignable(T, Z)>
{ };

template <class T, class Z>
constexpr bool AuIsNothrowAssignable_v = AuIsNothrowAssignable<T, Z>::value;

template <class T>
struct AuIsNothrowCopyAssignable : AuIsNothrowAssignable<AuAddLReference_t<T>, AuAddLReference_t<const T>>
{ };

template <class T>
constexpr bool AuIsNothrowCopyAssignable_v = AuIsNothrowCopyAssignable<T>::value;

template <class T>
struct AuIsNothrowMoveAssignable : AuIsNothrowAssignable<AuAddLReference_t<T>, T>
{ };

template <class T>
constexpr bool AuIsNothrowMoveAssignable_v = AuIsNothrowMoveAssignable<T>::value;

template <class T>
struct AuIsTriviallyCopyable : AuBoolType<__is_trivially_copyable(T)>
{ };

template <class T>
constexpr bool AuIsTriviallyCopyable_v = AuIsTriviallyCopyable<T>::value;

template <class T, class ... Args>
struct AuIsTriviallyConstructible : AuBoolType<__is_trivially_constructible(T, Args...)>
{ };

template <class T, class ... Args>
constexpr bool AuIsTriviallyConstructible_v = AuIsTriviallyConstructible<T, Args...>::value;

template <class T>
struct AuIsTriviallyMoveConstructible : AuIsTriviallyConstructible<T, T>
{ };

template <class T>
constexpr bool AuIsTriviallyMoveConstructible_v = AuIsTriviallyMoveConstructible<T>::value;

template <class T>
struct AuIsTriviallyCopyConstructible : AuIsTriviallyConstructible<T, AuAddLReference_t<const T>>
{ };

template <class T>
constexpr bool AuIsTriviallyCopyConstructible_v =  AuIsTriviallyCopyConstructible<T>::value;

template <class T>
struct AuIsTriviallyDefaultConstructible : AuIsTriviallyConstructible<T>
{ };

template <class T>
constexpr bool AuIsTriviallyDefaultConstructible_v = AuIsTriviallyDefaultConstructible<T>::value;

template <class T, class ... Args>
struct AuIsNothrowConstructible : AuBoolType<__is_nothrow_constructible(T, Args...)>
{ };

template <class T, class ... Args>
constexpr bool AuIsNothrowConstructible_v = AuIsNothrowConstructible<T, Args...>::value;

template <class T>
struct AuIsNothrowMoveConstructible : AuIsNothrowConstructible<T, T>
{ };

template <class T>
constexpr bool AuIsNothrowMoveConstructible_v = AuIsNothrowMoveConstructible<T>::value;

template <class T>
struct AuIsNothrowCopyConstructible : AuIsNothrowConstructible<T, AuAddLReference_t<const T>>
{ };

template <class T>
constexpr bool AuIsNothrowCopyConstructible_v =  AuIsNothrowCopyConstructible<T>::value;

template <class T>
struct AuIsNothrowDefaultConstructible : AuIsNothrowConstructible<T>
{ };

template <class T>
constexpr bool AuIsNothrowDefaultConstructible_v = AuIsNothrowDefaultConstructible<T>::value;