List.hpp

Go to the documentation of this file.

/****************************************************************************
 *
 *   Copyright (C) 2012-2019 PX4 Development Team. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name PX4 nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

#pragma once

#include <stdlib.h>

template<class T>
class ListNode
{
public:

    void setSibling(T sibling) { _sibling = sibling; }
    const T getSibling() const { return _sibling; }

protected:

    T _sibling{nullptr};

};

template<class T>
class List
{
public:

    void add(T newNode)
    {
        newNode->setSibling(getHead());
        _head = newNode;
    }

    bool remove(T removeNode)
    {
        // base case
        if (removeNode == _head) {
            _head = nullptr;
            return true;
        }

        for (T node = getHead(); node != nullptr; node = node->getSibling()) {
            // is sibling the node to remove?
            if (node->getSibling() == removeNode) {
                // replace sibling
                if (node->getSibling() != nullptr) {
                    node->setSibling(node->getSibling()->getSibling());

                } else {
                    node->setSibling(nullptr);
                }

                return true;
            }
        }

        return false;
    }

    struct Iterator {
        T node;
        Iterator(T v) : node(v) {}

        operator T() const { return node; }
        operator T &() { return node; }
        T operator* () const { return node; }
        Iterator &operator++ ()
        {
            if (node) {
                node = node->getSibling();
            };

            return *this;
        }
    };

    Iterator begin() { return Iterator(getHead()); }
    Iterator end() { return Iterator(nullptr); }

    const T getHead() const { return _head; }

    bool empty() const { return getHead() == nullptr; }

    size_t size() const
    {
        size_t sz = 0;

        for (auto node = getHead(); node != nullptr; node = node->getSibling()) {
            sz++;
        }

        return sz;
    }

    void deleteNode(T node)
    {
        if (remove(node)) {
            // only delete if node was successfully removed
            delete node;
        }
    }

    void clear()
    {
        auto node = getHead();

        while (node != nullptr) {
            auto next = node->getSibling();
            delete node;
            node = next;
        }

        _head = nullptr;
    }

protected:

    T _head{nullptr};
};