source: mainline/uspace/lib/cpp/include/internal/hash_table_bucket.hpp@ 614b07e

/*
 * Copyright (c) 2018 Jaroslav Jindrak
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

#ifndef LIBCPP_INTERNAL_HASH_TABLE_BUCKET
#define LIBCPP_INTERNAL_HASH_TABLE_BUCKET

#include <internal/list.hpp>

namespace std::aux
{
    template<class Value, class Size>
    struct hash_table_bucket
    {
        /**
         * Note: We use a doubly linked list because
         *       we need to use hints, which point to the
         *       element after the hinted spot.
         */

        list_node<Value>* head;

        hash_table_bucket()
            : head{}
        { /* DUMMY BODY */ }

        Size size() const noexcept
        {
            auto current = head;
            Size res{};

            do
            {
                ++res;
                current = current->next;
            }
            while (current != head);

            return res;
        }

        void append(list_node<Value>* node)
        {
            if (!head)
                head = node;
            else
                head->append(node);
        }

        void prepend(list_node<Value>* node)
        {
            if (!head)
                head = node;
            else
                head->prepend(node);
        }

        void clear()
        {
            if (!head)
                return;

            auto current = head;
            do
            {
                auto tmp = current;
                current = current->next;
                delete tmp;
            }
            while (current != head);

            head = nullptr;
        }

        ~hash_table_bucket()
        {
            clear();
        }
    };
}

#endif