UnorderedSet.hpp

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/*
    MIT License
 
    DiscordCoreAPI, A bot library for Discord, written in C++, and featuring explicit multithreading through the usage of custom, asynchronous C++ CoRoutines.
 
    Copyright 2022, 2023 Chris M. (RealTimeChris)
 
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/// UnorderedSet.hpp - Header file for the UnorderedSet class.
/// May 12, 2021
/// https://discordcoreapi.com
/// \file UnorderedSet.hpp
 
#pragma once
 
#include <discordcoreapi/Utilities/Hash.hpp>
 
namespace DiscordCoreAPI {
 
    template<typename ValueType> class UnorderedSet;
 
    template<typename SetIterator, typename ValueType>
    concept SetContainerIteratorT = std::is_same_v<typename UnorderedSet<ValueType>::iterator, std::decay_t<SetIterator>>;
 
    template<typename ValueType>
    class UnorderedSet : protected HashPolicy<UnorderedSet<ValueType>>, protected jsonifier_internal::alloc_wrapper<ValueType>, protected ObjectCompare, protected KeyAccessor {
      public:
        using mapped_type     = ValueType;
        using key_type        = mapped_type;
        using reference       = mapped_type&;
        using value_type      = mapped_type;
        using const_reference = const mapped_type&;
        using size_type       = uint64_t;
        using object_compare  = ObjectCompare;
        using key_accessor    = KeyAccessor;
        using hash_policy     = HashPolicy<UnorderedSet<mapped_type>>;
        using key_hasher      = hash_policy;
        using iterator        = HashIterator<UnorderedSet<mapped_type>>;
        using const_iterator  = HashIterator<const UnorderedSet<mapped_type>>;
        using allocator       = jsonifier_internal::alloc_wrapper<value_type>;
 
        friend hash_policy;
        friend iterator;
        friend const_iterator;
 
        inline UnorderedSet(){};
 
        inline UnorderedSet& operator=(UnorderedSet&& other) noexcept {
            if (this != &other) {
                reset();
                swap(other);
            }
            return *this;
        }
 
        inline UnorderedSet(UnorderedSet&& other) noexcept {
            *this = std::move(other);
        }
 
        inline UnorderedSet& operator=(const UnorderedSet& other) {
            if (this != &other) {
                reset();
 
                reserve(other.capacity());
                for (const auto& value: other) {
                    emplace(value);
                }
            }
            return *this;
        }
 
        inline UnorderedSet(const UnorderedSet& other) {
            *this = other;
        }
 
        inline UnorderedSet(std::initializer_list<value_type> list) {
            reserve(list.size());
            for (auto& value: list) {
                emplace(std::move(value));
            }
        };
 
        template<typename Args> iterator emplace(Args&& value) {
            return emplaceInternal(std::forward<Args>(value));
        }
 
        template<typename key_type_new> inline const_iterator find(key_type_new&& key) const {
            if (sizeVal > 0) {
                auto currentIndex = getKeyAccessor()(key) & (capacityVal - 1);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(getKeyAccessor()(data[currentIndex]), getKeyAccessor()(key))) {
                        return { this, currentIndex };
                    }
                }
            }
            return end();
        }
 
        template<typename key_type_new> inline iterator find(key_type_new&& key) {
            if (sizeVal > 0) {
                auto currentIndex = getKeyAccessor()(key) & (capacityVal - 1);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(getKeyAccessor()(data[currentIndex]), getKeyAccessor()(key))) {
                        return { this, currentIndex };
                    }
                }
            }
            return end();
        }
 
        template<typename key_type_new> inline const_reference operator[](key_type_new&& key) const {
            auto iter = find(std::forward<key_type_new>(key));
            if (iter == end()) {
                iter = emplace(mapped_type{});
            }
            return *iter;
        }
 
        template<typename key_type_new> inline reference operator[](key_type_new&& key) {
            auto iter = find(std::forward<key_type_new>(key));
            if (iter == end()) {
                iter = emplace(mapped_type{});
            }
            return *iter;
        }
 
        template<typename key_type_new> inline const_reference at(key_type_new&& key) const {
            auto iter = find(std::forward<key_type_new>(key));
            if (iter == end()) {
                throw DCAException{ "Sorry, but an object by that key doesn't exist in this map." };
            }
            return *iter;
        }
 
        template<typename key_type_new> inline reference at(key_type_new&& key) {
            auto iter = find(std::forward<key_type_new>(key));
            if (iter == end()) {
                throw DCAException{ "Sorry, but an object by that key doesn't exist in this map." };
            }
            return *iter;
        }
 
        template<typename key_type_new> inline bool contains(key_type_new&& key) const {
            if (sizeVal > 0) {
                auto currentIndex = getKeyAccessor()(key) & (capacityVal - 1);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(getKeyAccessor().operator()(data[currentIndex]), getKeyAccessor().operator()(key))) {
                        return true;
                    }
                }
            }
            return false;
        }
 
        template<SetContainerIteratorT<mapped_type> SetIterator> inline iterator erase(SetIterator&& iter) {
            if (sizeVal > 0) {
                auto currentIndex = static_cast<size_type>(iter.getRawPtr() - data);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(getKeyAccessor()(data[currentIndex]), getKeyAccessor()(iter.operator*()))) {
                        sentinelVector[currentIndex] = 0;
                        sizeVal--;
                        return { this, ++currentIndex };
                    }
                }
            }
            return end();
        }
 
        template<typename key_type_new> inline iterator erase(key_type_new&& key) {
            if (sizeVal > 0) {
                auto currentIndex = getKeyAccessor()(key) & (capacityVal - 1);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(getKeyAccessor()(data[currentIndex]), getKeyAccessor()(key))) {
                        sentinelVector[currentIndex] = 0;
                        sizeVal--;
                        return { this, ++currentIndex };
                    }
                }
            }
            return end();
        }
 
        inline const_iterator begin() const {
            for (size_type x{ 0 }; x < capacityVal; ++x) {
                if (sentinelVector[x] > 0) {
                    return { this, x };
                }
            }
            return end();
        }
 
        inline const_iterator end() const {
            return {};
        }
 
        inline iterator begin() {
            for (size_type x{ 0 }; x < capacityVal; ++x) {
                if (sentinelVector[x] > 0) {
                    return { this, x };
                }
            }
            return end();
        }
 
        inline iterator end() {
            return {};
        }
 
        inline bool full() const {
            return static_cast<float>(sizeVal) >= static_cast<float>(capacityVal) * 0.90f;
        }
 
        inline size_type size() const {
            return sizeVal;
        }
 
        inline bool empty() const {
            return sizeVal == 0;
        }
 
        inline void reserve(size_type sizeNew) {
            resize(sizeNew);
        }
 
        inline void swap(UnorderedSet& other) noexcept {
            std::swap(maxLookAheadDistance, other.maxLookAheadDistance);
            std::swap(sentinelVector, other.sentinelVector);
            std::swap(capacityVal, other.capacityVal);
            std::swap(sizeVal, other.sizeVal);
            std::swap(data, other.data);
        }
 
        inline size_type capacity() const {
            return capacityVal;
        }
 
        inline bool operator==(const UnorderedSet& other) const {
            if (capacityVal != other.capacityVal || sizeVal != other.sizeVal || data != other.data) {
                return false;
            }
            for (auto iter01{ begin() }, iter02{ other.begin() }; iter01 != end(); ++iter01, ++iter02) {
                if (!object_compare()(iter01.operator*(), iter02.operator*())) {
                    return false;
                }
            }
            return true;
        }
 
        inline void clear() {
            for (size_type x = 0; x < sentinelVector.size(); ++x) {
                if (sentinelVector[x] > 0) {
                    getAlloc().destroy(data + x);
                    sentinelVector[x] = 0;
                }
            }
            sizeVal = 0;
        }
 
        inline ~UnorderedSet() {
            reset();
        };
 
      protected:
        jsonifier::vector<int8_t> sentinelVector{};
        int8_t maxLookAheadDistance{ minLookups };
        size_type capacityVal{};
        size_type sizeVal{};
        value_type* data{};
 
        template<typename mapped_type_new> inline iterator emplaceInternal(mapped_type_new&& value) {
            if (full() || capacityVal == 0) {
                resize(capacityVal + 1);
            }
            auto currentIndex = getKeyAccessor()(value) & (capacityVal - 1);
            for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                if (sentinelVector[currentIndex] == 0) {
                    new (std::addressof(data[currentIndex])) value_type{ std::forward<mapped_type_new>(value) };
                    sentinelVector[currentIndex] = 1;
                    sizeVal++;
                    return { this, currentIndex };
                } else if (sentinelVector[currentIndex] > 0 && object_compare()(getKeyAccessor()(data[currentIndex]), getKeyAccessor()(value))) {
                    if constexpr (!std::is_void_v<mapped_type_new>) {
                        data[currentIndex] = std::forward<mapped_type_new>(value);
                    }
                    return { this, currentIndex };
                }
            }
            resize(capacityVal + 1);
            return emplaceInternal(std::forward<mapped_type_new>(value));
        }
 
        inline allocator& getAlloc() {
            return *this;
        }
 
        inline const hash_policy& getHashPolicy() const {
            return *this;
        }
 
        inline const key_accessor& getKeyAccessor() const {
            return *this;
        }
 
        inline void resize(size_type capacityNew) {
            auto newSize = getHashPolicy().nextPowerOfTwo(capacityNew);
            if (newSize > capacityVal) {
                jsonifier::vector<int8_t> oldSentinelVector = std::move(sentinelVector);
                auto oldMaxLookAheadDistance                = maxLookAheadDistance;
                auto oldCapacity                            = capacityVal;
                auto oldSize                                = sizeVal;
                auto oldPtr                                 = data;
                maxLookAheadDistance                        = getHashPolicy().computeMaxLookAheadDistance(newSize);
                sizeVal                                     = 0;
                data                                        = getAlloc().allocate(newSize + 1 + maxLookAheadDistance);
                sentinelVector.resize(newSize + 1 + maxLookAheadDistance);
                sentinelVector[newSize + maxLookAheadDistance] = -1;
                capacityVal                                    = newSize;
                for (size_type x = 0, y = 0; y < oldSize; ++x) {
                    if (oldSentinelVector[x] > 0) {
                        ++y;
                        emplaceInternal(std::move(oldPtr[x]));
                    }
                }
                if (oldPtr && oldCapacity) {
                    getAlloc().deallocate(oldPtr, oldCapacity + 1 + oldMaxLookAheadDistance);
                }
            }
        }
 
        inline void reset() {
            if (data && sizeVal > 0) {
                for (uint64_t x = 0; x < sentinelVector.size(); ++x) {
                    if (sentinelVector[x] > 0) {
                        getAlloc().destroy(data + x);
                    }
                }
                getAlloc().deallocate(data, capacityVal + 1 + maxLookAheadDistance);
                sentinelVector.clear();
                sizeVal     = 0;
                capacityVal = 0;
                data        = nullptr;
            }
        }
    };
}