/// <summary>
/// Copyright (C) 2004-2021 Free Software Foundation, Inc.
///
/// Author: Alexander Gnauck AG-Software, mailto:gnauck@ag-software.de
///
/// This file is part of GNU Libidn.
///
/// GNU Libidn is free software: you can redistribute it and/or
/// modify it under the terms of either:
///
///   * the GNU Lesser General Public License as published by the Free
///     Software Foundation; either version 3 of the License, or (at
///     your option) any later version.
///
/// or
///
///   * the GNU General Public License as published by the Free
///     Software Foundation; either version 2 of the License, or (at
///     your option) any later version.
///
/// or both in parallel, as here.
///
/// GNU Libidn is distributed in the hope that it will be useful,
/// but WITHOUT ANY WARRANTY; without even the implied warranty of
/// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
/// General Public License for more details.
///
/// You should have received copies of the GNU General Public License and
/// the GNU Lesser General Public License along with this program.  If
/// not, see <http://www.gnu.org/licenses/>.
/// </summary>

using System;
using System.Collections;

namespace gnu.inet.encoding.misc
{
    /// <summary>
    /// HashSet class.
    /// </summary>
    public class HashSet : ArrayList
    {
        public HashSet() : base()
        {
        }

        public HashSet(System.Collections.ICollection c)
        {
            this.AddAll(c);
        }

        public HashSet(int capacity) : base(capacity)
        {
        }

        /// <summary>
        /// Adds a new element to the ArrayList if it is not already present.
        /// </summary>
        /// <param name="obj">Element to insert to the ArrayList.</param>
        /// <returns>Returns true if the new element was inserted, false otherwise.</returns>
        new public virtual bool Add(System.Object obj)
        {
            bool inserted;

            if ((inserted = this.Contains(obj)) == false)
            {
                base.Add(obj);
            }

            return !inserted;
        }

        /// <summary>
        /// Adds all the elements of the specified collection that are not present to the list.
        /// </summary>
        /// <param name="c">Collection where the new elements will be added</param>
        /// <returns>Returns true if at least one element was added, false otherwise.</returns>
        public bool AddAll(System.Collections.ICollection c)
        {
            System.Collections.IEnumerator e = new System.Collections.ArrayList(c).GetEnumerator();
            bool added = false;

            while (e.MoveNext() == true)
            {
                if (this.Add(e.Current) == true)
                    added = true;
            }

            return added;
        }

        /// <summary>
        /// Returns a copy of the HashSet instance.
        /// </summary>
        /// <returns>Returns a shallow copy of the current HashSet.</returns>
        public override System.Object Clone()
        {
            return base.MemberwiseClone();
        }
    }
}
