Kylin/DataStructure/CircularLinkedList.h

#ifndef CIRCULARLIST_H
#define CIRCULARLIST_H

#include "LinkedList.h"

namespace Kylin {
template <typename T>
class CircularLinkedList : public LinkedList<T> {
    using Node = typename LinkedList<T>::Node;
    using Iterator = typename LinkedList<T>::Iterator;

public:
    CircularLinkedList() = default;
    CircularLinkedList(std::initializer_list<T> init) {
        this->m_header.next = reinterpret_cast<Node *>(&this->m_header);
        this->m_last = reinterpret_cast<Node *>(&this->m_header);

        for (auto &value : init) {
            this->append(value);
        }
    }

    CircularLinkedList(const CircularLinkedList &other) {
        this->m_header.next = reinterpret_cast<Node *>(&this->m_header);
        this->m_last = reinterpret_cast<Node *>(&this->m_header);

        auto sourceNode = other.m_header.next;
        auto targetNode = reinterpret_cast<Node *>(&this->m_header);
        for (size_t i = 0; i < other.m_size; i++) {
            auto newNode = this->create();
            if (newNode == nullptr) THROW_EXCEPTION(NoEnoughMemoryException, "No memory to create node ...");
            newNode->value = sourceNode->value;
            targetNode->next = newNode;
            targetNode = newNode;
            sourceNode = sourceNode->next;
            this->m_size++;
            targetNode->next = this->m_header.next;
            this->m_last = targetNode;
        }
    }

    CircularLinkedList(CircularLinkedList &&other) {
        this->m_size = other.m_size;
        this->m_header = other.m_header;
        this->m_last = other.m_last;

        other.m_size = 0;
        other.m_header.next = nullptr;
        other.m_last = reinterpret_cast<Node *>(&other.m_header);
    }

    void insert(size_t index, const T &value) override {
        index = index % (this->m_size + 1);
        if (index == this->m_size) return this->append(value);
        LinkedList<T>::insert(index, value);
        if (index == 0) lastToFirst();
    }

    void removeAt(size_t index) override {
        if (this->size() <= 0)
            THROW_EXCEPTION(IndexOutOfBoundsException, "There is no element in the container.");
        index = mod(index);
        if (index == 0) {
            auto toDel = this->m_header.next;
            this->m_header.next = toDel->next;
            this->m_size--;
            if (this->m_size == 0) {
                this->m_header.next = nullptr;
            } else {
                lastToFirst();
            }
            this->destroy(toDel);
        } else {
            LinkedList<T>::removeAt(index);
        }
    }

    virtual void clear() {
        while (this->m_size > 1) {
            removeAt(1);
        }
        if (this->m_size == 1) {
            auto del = this->m_header.next;
            this->m_header.next = nullptr;
            this->m_size = 0;
            this->destroy(del);
        }
    }

    Iterator end() override { return Iterator(reinterpret_cast<Node *>(&this->m_header)); }

    Iterator end() const override { return Iterator(reinterpret_cast<Node *>(&this->m_header)); }

    T &operator[](size_t index) override {
        if (this->m_size <= 0)
            THROW_EXCEPTION(InvalidOperationException, "There is no element in the container...");
        index = mod(index);
        return this->position(index)->next->value;
    }

    virtual ~CircularLinkedList() { clear(); }

protected:
    size_t mod(size_t index) const { return (this->m_size == 0) ? 0 : (index % this->m_size); }

    void lastToFirst() { this->position(this->m_size - 1)->next->next = this->m_header.next; }
};
} // namespace Kylin
#endif // CIRCULARLIST_H