UnorderedMap.hpp

/*
    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)
 
    Permission is hereby granted, free of charge, to any person obtaining a copy
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    furnished to do so, subject to the following conditions:
 
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    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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*/
/// unordered_map.hpp - Header file for the unordered_map class.
/// May 12, 2021
/// https://discordcoreapi.com
/// \file unordered_map.hpp
#pragma once
 
#include <discordcoreapi/Utilities/Hash.hpp>
#include <discordcoreapi/Utilities/UniquePtr.hpp>
 
#include <memory_resource>
#include <shared_mutex>
#include <exception>
#include <optional>
#include <utility>
#include <vector>
#include <mutex>
 
namespace discord_core_api {
 
    template<typename key_type, typename value_type> class unordered_map;
 
    template<typename map_iterator, typename key_type, typename value_type>
    concept map_container_iterator_t = std::same_as<typename unordered_map<key_type, value_type>::iterator, std::decay_t<map_iterator>>;
 
    template<typename key_type_new, typename value_type_new> class unordered_map : protected hash_policy<unordered_map<key_type_new, value_type_new>>,
                                                                                   protected jsonifier_internal::alloc_wrapper<std::pair<key_type_new, value_type_new>>,
                                                                                   protected object_compare {
      public:
        using key_type          = key_type_new;
        using value_type        = std::pair<key_type_new, value_type_new>;
        using allocator_type    = jsonifier_internal::alloc_wrapper<value_type>;
        using allocator_traits  = std::allocator_traits<allocator_type>;
        using size_type         = uint64_t;
        using difference_type   = int64_t;
        using pointer           = typename allocator_traits::pointer;
        using const_pointer     = typename allocator_traits::const_pointer;
        using mapped_type       = value_type_new;
        using reference         = value_type&;
        using const_reference   = const value_type&;
        using iterator          = hash_iterator<unordered_map<key_type, mapped_type>>;
        using const_iterator    = hash_iterator<const unordered_map<key_type, mapped_type>>;
        using object_compare    = object_compare;
        using hash_policy_new   = hash_policy<unordered_map<key_type, mapped_type>>;
 
        friend hash_policy_new;
        friend iterator;
        friend const_iterator;
 
        DCA_INLINE unordered_map(){};
 
        DCA_INLINE unordered_map& operator=(unordered_map&& other) noexcept {
            if (this != &other) {
                reset();
                swap(other);
            }
            return *this;
        }
 
        DCA_INLINE unordered_map(unordered_map&& other) noexcept {
            *this = std::move(other);
        }
 
        DCA_INLINE unordered_map& operator=(const unordered_map& other) {
            if (this != &other) {
                reset();
 
                reserve(other.capacity());
                for (const auto& [key, value]: other) {
                    emplace(key, value);
                }
            }
            return *this;
        }
 
        DCA_INLINE unordered_map(const unordered_map& other) {
            *this = other;
        }
 
        DCA_INLINE unordered_map(std::initializer_list<value_type> list) {
            reserve(list.size());
            for (auto& value: list) {
                emplace(std::move(value.first), std::move(value.second));
            }
        };
 
        template<typename... Args> iterator emplace(Args&&... value) {
            return emplaceInternal(std::forward<Args>(value)...);
        }
 
        template<typename key_type_newer> DCA_INLINE const_iterator find(key_type_newer&& key) const {
            if (sizeVal > 0) {
                auto currentIndex = hash_policy_new::indexForHash(key);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(data[currentIndex].first, key)) {
                        return { this, currentIndex };
                    }
                }
            }
            return end();
        }
 
        template<typename key_type_newer> DCA_INLINE iterator find(key_type_newer&& key) {
            if (sizeVal > 0) {
                auto currentIndex = hash_policy_new::indexForHash(key);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(data[currentIndex].first, key)) {
                        return { this, currentIndex };
                    }
                }
            }
            return end();
        }
 
        template<typename key_type_newer> DCA_INLINE const mapped_type& operator[](key_type_newer&& key) const {
            return emplaceInternal(key)->second;
        }
 
        template<typename key_type_newer> DCA_INLINE mapped_type& operator[](key_type_newer&& key) {
            return emplaceInternal(key)->second;
        }
 
        template<typename key_type_newer> DCA_INLINE const mapped_type& at(key_type_newer&& key) const {
            auto iter = find(std::forward<key_type_newer>(key));
            if (iter == end()) {
                throw std::runtime_error{ "Sorry, but an object by that key doesn't exist in this map." };
            }
            return iter->second;
        }
 
        template<typename key_type_newer> DCA_INLINE mapped_type& at(key_type_newer&& key) {
            auto iter = find(std::forward<key_type_newer>(key));
            if (iter == end()) {
                throw std::runtime_error{ "Sorry, but an object by that key doesn't exist in this map." };
            }
            return iter->second;
        }
 
        template<typename key_type_newer> DCA_INLINE bool contains(key_type_newer&& key) const {
            if (sizeVal > 0) {
                auto currentIndex = hash_policy_new::indexForHash(key);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(data[currentIndex].first, key)) {
                        return true;
                    }
                }
            }
            return false;
        }
 
        template<map_container_iterator_t<key_type, mapped_type> map_iterator> DCA_INLINE iterator erase(map_iterator&& 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()(data[currentIndex], iter.operator*())) {
                        allocator_traits::destroy(*this, data + currentIndex);
                        sentinelVector[currentIndex] = 0;
                        --sizeVal;
                        return { this, ++currentIndex };
                    }
                }
            }
            return end();
        }
 
        template<typename key_type_newer> DCA_INLINE iterator erase(key_type_newer&& key) {
            if (sizeVal > 0) {
                auto currentIndex = hash_policy_new::indexForHash(key);
                for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                    if (sentinelVector[currentIndex] > 0 && object_compare()(data[currentIndex].first, key)) {
                        allocator_traits::destroy(*this, data + currentIndex);
                        sentinelVector[currentIndex] = 0;
                        --sizeVal;
                        return { this, ++currentIndex };
                    }
                }
            }
            return end();
        }
 
        DCA_INLINE const_iterator begin() const {
            for (size_type x{ 0 }; x < capacityVal; ++x) {
                if (sentinelVector.at(x) > 0) {
                    return { this, x };
                }
            }
            return end();
        }
 
        DCA_INLINE const_iterator end() const {
            return {};
        }
 
        DCA_INLINE iterator begin() {
            for (size_type x{ 0 }; x < capacityVal; ++x) {
                if (sentinelVector.at(x) > 0) {
                    return { this, x };
                }
            }
            return end();
        }
 
        DCA_INLINE iterator end() {
            return {};
        }
 
        DCA_INLINE bool full() const {
            return static_cast<float>(sizeVal) >= static_cast<float>(capacityVal) * 0.90f;
        }
 
        DCA_INLINE size_type size() const {
            return sizeVal;
        }
 
        DCA_INLINE bool empty() const {
            return sizeVal == 0;
        }
 
        DCA_INLINE void reserve(size_type sizeNew) {
            resize(sizeNew);
        }
 
        DCA_INLINE void swap(unordered_map& other) {
            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);
        }
 
        DCA_INLINE size_type capacity() const {
            return capacityVal;
        }
 
        DCA_INLINE bool operator==(const unordered_map& 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*().second, iter02.operator*().second)) {
                    return false;
                }
            }
            return true;
        }
 
        DCA_INLINE void clear() {
            for (size_type x = 0; x < sentinelVector.size(); ++x) {
                if (sentinelVector.at(x) > 0) {
                    allocator_traits::destroy(*this, data + x);
                    sentinelVector.at(x) = 0;
                }
            }
            sizeVal = 0;
        }
 
        DCA_INLINE ~unordered_map() {
            reset();
        };
 
      protected:
        jsonifier::vector<int8_t> sentinelVector{};
        int8_t maxLookAheadDistance{ 0 };
        size_type capacityVal{};
        size_type sizeVal{};
        value_type* data{};
 
        template<typename key_type_newer, typename... mapped_type_new> DCA_INLINE iterator emplaceInternal(key_type_newer&& key, mapped_type_new&&... value) {
            if (full() || capacityVal == 0) {
                resize(capacityVal + 1);
            }
            auto currentIndex = hash_policy_new::indexForHash(key);
            for (size_type x{}; x < static_cast<size_type>(maxLookAheadDistance); ++x, ++currentIndex) {
                if (sentinelVector[currentIndex] == 0) {
                    if constexpr ((( !std::is_void_v<mapped_type_new> ) || ...)) {
                        new (std::addressof(data[currentIndex])) value_type{ std::make_pair(std::forward<key_type_newer>(key), std::forward<mapped_type_new>(value)...) };
                    } else {
                        new (std::addressof(data[currentIndex])) value_type{ std::make_pair(std::forward<key_type_newer>(key), mapped_type{}) };
                    }
                    sentinelVector[currentIndex] = 1;
                    sizeVal++;
                    return { this, currentIndex };
                } else if (sentinelVector[currentIndex] > 0 && object_compare()(data[currentIndex].first, key)) {
                    if constexpr ((( !std::is_void_v<mapped_type_new> ) || ...)) {
                        data[currentIndex].second = mapped_type{ std::forward<mapped_type_new>(value)... };
                    }
                    return { this, currentIndex };
                }
            }
            resize(capacityVal + 1);
            return emplaceInternal(std::forward<key_type_newer>(key), std::forward<mapped_type_new>(value)...);
        }
 
        DCA_INLINE void resize(size_type capacityNew) {
            auto newSize = hash_policy_new::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                        = hash_policy_new::computeMaxLookAheadDistance(newSize);
                sizeVal                                     = 0;
                data                                        = allocator_traits::allocate(*this, 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.at(x) > 0) {
                        ++y;
                        emplaceInternal(std::move(oldPtr[x].first), std::move(oldPtr[x].second));
                    }
                }
                if (oldPtr && oldCapacity) {
                    allocator_traits::deallocate(*this, oldPtr, oldCapacity + 1 + oldMaxLookAheadDistance);
                }
            }
        }
 
        DCA_INLINE void reset() {
            if (data && sizeVal > 0) {
                for (uint64_t x = 0; x < sentinelVector.size(); ++x) {
                    if (sentinelVector.at(x) > 0) {
                        allocator_traits::destroy(*this, data + x);
                        sentinelVector.at(x) = 0;
                    }
                }
                allocator_traits::deallocate(*this, data, capacityVal + 1 + maxLookAheadDistance);
                sentinelVector.clear();
                sizeVal     = 0;
                capacityVal = 0;
                data        = nullptr;
            }
        }
    };
 
 
}