RotatingList Demo

Program.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Runtime.Serialization;
using System.Linq;

public class Program
{
    public static void Main()
    {
        RotatingList<double> rotatingList = new() { 1, 2, 3 };
        Console.WriteLine(string.Join(", ", rotatingList));

        rotatingList.Add(4);
        Console.WriteLine(string.Join(", ", rotatingList));
        rotatingList.Add(5);
        Console.WriteLine(string.Join(", ", rotatingList));
    }
}

public class RotatingList<T> : ICollection<T>, IEnumerable<T>, IEnumerable, IReadOnlyCollection<T>, ICollection, IDeserializationCallback, ISerializable
{
    private readonly LinkedList<T> m_LinkedList = new();

    private readonly uint m_MaxSize;

    public int Count => ((ICollection<T>)m_LinkedList).Count;

    public bool IsReadOnly => ((ICollection<T>)m_LinkedList).IsReadOnly;

    public bool IsSynchronized => ((ICollection)m_LinkedList).IsSynchronized;

    public object SyncRoot => ((ICollection)m_LinkedList).SyncRoot;

    public RotatingList(uint maxSize = 3)
    {
        m_MaxSize = maxSize;
    }

    private void RemoveLastAndAddFirst(T elementToAdd)
    {
        if (m_LinkedList.Count >= m_MaxSize) { m_LinkedList.RemoveLast(); }
        m_LinkedList.AddFirst(elementToAdd);
    }

    public void Add(T element)
    {
        RemoveLastAndAddFirst(element);
    }

    public T? GetNewestElementOrDefault()
    {
        return m_LinkedList.FirstOrDefault();
    }

    public T? GetOldestElementOrDefault()
    {
        return m_LinkedList.LastOrDefault();
    }

    public T GetNewestElement()
    {
        return m_LinkedList.First();
    }

    public T GetOldestElement()
    {
        return m_LinkedList.Last();
    }

    public void Clear()
    {
        ((ICollection<T>)m_LinkedList).Clear();
    }

    public bool Contains(T item)
    {
        return ((ICollection<T>)m_LinkedList).Contains(item);
    }

    public void CopyTo(T[] array, int arrayIndex)
    {
        ((ICollection<T>)m_LinkedList).CopyTo(array, arrayIndex);
    }

    public bool Remove(T item)
    {
        return ((ICollection<T>)m_LinkedList).Remove(item);
    }

    public IEnumerator<T> GetEnumerator()
    {
        return ((IEnumerable<T>)m_LinkedList).GetEnumerator();
    }

    System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
    {
        return ((System.Collections.IEnumerable)m_LinkedList).GetEnumerator();
    }

    public void CopyTo(Array array, int index)
    {
        ((ICollection)m_LinkedList).CopyTo(array, index);
    }

    public void OnDeserialization(object? sender)
    {
        ((IDeserializationCallback)m_LinkedList).OnDeserialization(sender);
    }

    public void GetObjectData(SerializationInfo info, StreamingContext context)
    {
        ((ISerializable)m_LinkedList).GetObjectData(info, context);
    }
}