KeyedCollection_Factory.inl

/*
 * Copyright(c) Sophist Solutions, Inc. 1990-2025.  All rights reserved
 */
#include "Stroika/Foundation/Containers/Concrete/KeyedCollection_Array.h"
#include "Stroika/Foundation/Containers/Concrete/KeyedCollection_stdhashset.h"
#include "Stroika/Foundation/Containers/Concrete/SortedKeyedCollection_stdset.h"
 
namespace Stroika::Foundation::Containers::Factory {
 
    /*
     ********************************************************************************
     ****** KeyedCollection_Factory<T, KEY_TYPE, TRAITS, KEY_EQUALS_COMPARER> *******
     ********************************************************************************
     */
    template <typename T, typename KEY_TYPE, typename TRAITS, typename KEY_EQUALS_COMPARER>
    constexpr KeyedCollection_Factory<T, KEY_TYPE, TRAITS, KEY_EQUALS_COMPARER>::KeyedCollection_Factory (const FactoryFunctionType& f)
        : fFactory_{f}
    {
    }
    template <typename T, typename KEY_TYPE, typename TRAITS, typename KEY_EQUALS_COMPARER>
    constexpr KeyedCollection_Factory<T, KEY_TYPE, TRAITS, KEY_EQUALS_COMPARER>::KeyedCollection_Factory ()
        : KeyedCollection_Factory{AccessDefault_ ()}
    {
    }
    template <typename T, typename KEY_TYPE, typename TRAITS, typename KEY_EQUALS_COMPARER>
    constexpr KeyedCollection_Factory<T, KEY_TYPE, TRAITS, KEY_EQUALS_COMPARER>::KeyedCollection_Factory ([[maybe_unused]] const Hints& hints)
        : fFactory_{nullptr}
    {
    }
    template <typename T, typename KEY_TYPE, typename TRAITS, typename KEY_EQUALS_COMPARER>
    inline auto KeyedCollection_Factory<T, KEY_TYPE, TRAITS, KEY_EQUALS_COMPARER>::Default () -> const KeyedCollection_Factory&
    {
        return AccessDefault_ ();
    }
    template <typename T, typename KEY_TYPE, typename TRAITS, typename KEY_EQUALS_COMPARER>
    inline auto KeyedCollection_Factory<T, KEY_TYPE, TRAITS, KEY_EQUALS_COMPARER>::operator() (const KeyExtractorType& keyExtractor,
                                                                                               const KEY_EQUALS_COMPARER& keyComparer) const -> ConstructedType
    {
        if (this->fFactory_ == nullptr) [[likely]] {
            if constexpr (default_initializable<Concrete::KeyedCollection_stdhashset<T, KEY_TYPE, TRAITS>> and
                          same_as<KEY_EQUALS_COMPARER, equal_to<KEY_TYPE>>) {
                return Concrete::KeyedCollection_stdhashset<T, KEY_TYPE, TRAITS>{keyExtractor};
            }
            else if constexpr (default_initializable<Concrete::SortedKeyedCollection_stdset<T, KEY_TYPE, TRAITS>> and
                               same_as<KEY_EQUALS_COMPARER, equal_to<KEY_TYPE>>) {
                return Concrete::SortedKeyedCollection_stdset<T, KEY_TYPE, TRAITS>{keyExtractor}; // if using == as equals comparer, just map to < for in-order comparison
            }
            else {
                /*
                 *  Note - though this is not an efficient implementation of KeyedCollection<> for large sizes, its probably the most
                 *  efficient representation which adds no requirements to KEY_TYPE, such as operator< (or a traits less) or
                 *  a hash function. And its quite reasonable for small KeyedCollection's - which are often the case.
                 *
                 *  Note, array CAN be slower than LinkedList as the size grows (array faster when small due to better locality).
                 *  But the whole thing bogs down no matter what, when larger, cuz you really need some indexed data structure like a tree.
                 */
                return Concrete::KeyedCollection_Array<T, KEY_TYPE, TRAITS>{keyExtractor, keyComparer};
            }
        }
        else {
            return this->fFactory_ (keyExtractor, keyComparer);
        }
    }
    template <typename T, typename KEY_TYPE, typename TRAITS, typename KEY_EQUALS_COMPARER>
    void KeyedCollection_Factory<T, KEY_TYPE, TRAITS, KEY_EQUALS_COMPARER>::Register (const optional<KeyedCollection_Factory>& f)
    {
        AccessDefault_ () = f.has_value () ? *f : KeyedCollection_Factory{Hints{}};
    }
    template <typename T, typename KEY_TYPE, typename TRAITS, typename KEY_EQUALS_COMPARER>
    inline auto KeyedCollection_Factory<T, KEY_TYPE, TRAITS, KEY_EQUALS_COMPARER>::AccessDefault_ () -> KeyedCollection_Factory&
    {
        static KeyedCollection_Factory sDefault_{Hints{}};
        return sDefault_;
    }
 
}