IList<T> decorator holding a max number of items using FIFO

MaxItemList.cs

using System;
using System.Collections.Generic;

namespace Reid.Collections
{
	public class MaxItemList<T> : IList<T>
	{
		readonly IList<T> _list;
		readonly int _maxItems;

		public MaxItemList(IList<T> list, int maximumItems)
		{
			if (list == null) throw new ArgumentNullException("list");
			if (maximumItems <= 0) throw new ArgumentException("MaximumItems must be a positive integer");
			
			_list = list;
			_maxItems = maximumItems;
		}

		public bool Contains(T item)
		{
			return _list.Contains(item);
		}

		public void Add(T item)
		{
			if (item == null) throw new ArgumentNullException("item");

			MakeSpace();
			_list.Add(item);
		}

		public int IndexOf(T item)
		{
			return _list.IndexOf(item);
		}

		public void Insert(int index, T item)
		{
			MakeSpace();
			_list.Insert(index, item);
		}

		public void RemoveAt(int index)
		{
			_list.RemoveAt(index);
		}

		public T this[int index]
		{
			get
			{
				return _list[index];
			}
			set
			{
				_list[index] = value;
			}
		}

		public void Clear()
		{
			_list.Clear();
		}

		public void CopyTo(T[] array, int arrayIndex)
		{
			_list.CopyTo(array, arrayIndex);
		}

		public int Count
		{
			get { return _list.Count; }
		}

		public bool IsReadOnly
		{
			get { return _list.IsReadOnly; }
		}

		public bool Remove(T item)
		{
			return _list.Remove(item);
		}

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

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

		void MakeSpace()
		{
			if (_list.Count == _maxItems) _list.Remove(_list[0]);
		}
	}
}