// arraytest.cs -- a demonstration of various ways you might process an IList<T> array
// © 2006 Microsoft Corporation 
// This program is offered AS IS with no warranty implied and confers no rights.
// Also please don't run around the house while holding scissors; thank you.  

using System;
using System.Collections.Generic;
using System.Collections;
using System.Text;

namespace ArrayTest
{
    class Program
    {
        class Test {
            static public int Sum(IList<ushort> indices)
            {
                int result = 0;

                for (int i = 0; i < indices.Count; i++) 
                    result += indices[i];

                return result;
            }

            static public int SumForeach(IList<ushort> indices)
            {   
                int result = 0;
                foreach (ushort us in indices)
                    result += us;

                return result;
            }      

            static public int SumSpecial(IList<ushort> indices)
            {   
                int result = 0;

                ushort[] arr = indices as ushort[];

                if (arr != null)
                {
                    foreach (ushort us in arr)
                        result += us;
                }
                else
                {
                    foreach (ushort us in indices)
                        result += us;
                }
     

                return result;
            }      

        }

        class ArrayWrapper<T> : IList<T>
        {
            private T[] arr;

            public ArrayWrapper(T[] _arr) 
            { 
                arr = _arr;
            }


            T IList<T>.this[int index] { 
                get {
                    return arr[index];
                }
                set {
                    throw new System.NotImplementedException();
                }
            }

            private void NYI() { throw new System.NotImplementedException(); }

            int  IList<T>.IndexOf(T item) { NYI(); return -1;}
            void IList<T>.Insert(int index, T item) { NYI(); }
            void IList<T>.RemoveAt(int index) { NYI(); }
            int  ICollection<T>.Count { get { return arr.Length; } }
            bool ICollection<T>.IsReadOnly { get { return true; } }
            void ICollection<T>.Add(T item) { NYI(); }
            void ICollection<T>.Clear() { NYI(); }
            bool ICollection<T>.Contains(T item) { NYI(); return false;}
            void ICollection<T>.CopyTo(T[] array, int arrayIndex) { NYI(); }
            bool ICollection<T>.Remove(T item) { NYI(); return false;}
            IEnumerator<T> IEnumerable<T>.GetEnumerator() { NYI(); return null;}
            IEnumerator IEnumerable.GetEnumerator() { NYI(); return null;}
        }

        static void Main(string[] args)
        {
            int iterations = 500000;

            Test test = new Test();
            ushort[] arr = new ushort[iterations];

            List<ushort> lst = new List<ushort>(iterations);
            for (int i = 0; i < iterations; i++) 
                lst.Add(0);

            ArrayWrapper<ushort> aw = new ArrayWrapper<ushort>(new ushort[iterations]);

            Test1(arr);
            Test2(lst);
            Test3(aw);
            Test4(arr);
            Test5(lst);
            Test6(arr);
            Test7(lst);
        }

        static void Test1(ushort[] arr)
        {
            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();

            sw.Start();
            Test.Sum(arr);
            sw.Stop();

            Console.WriteLine("Elapsed Milliseconds Array: {0}", sw.ElapsedMilliseconds);
        }

        static void Test2(List<ushort> lst)
        {
            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();

            sw.Start();
            Test.Sum(lst); 
            sw.Stop();

            Console.WriteLine("Elapsed Milliseconds List<>: {0}", sw.ElapsedMilliseconds);
        }

        static void Test3(ArrayWrapper<ushort> aw)
        {
            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();

            sw.Start();
            Test.Sum(aw); 
            sw.Stop();

            Console.WriteLine("Elapsed Milliseconds ArrayWrapper: {0}", sw.ElapsedMilliseconds);
        }

        static void Test4(ushort[] arr)
        {
            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();

            sw.Start();
            Test.SumForeach(arr);
            sw.Stop();

            Console.WriteLine("Elapsed Milliseconds Array via foreach: {0}", sw.ElapsedMilliseconds);
        }

        static void Test5(List<ushort> lst)
        {
            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();

            sw.Start();
            Test.SumForeach(lst); 
            sw.Stop();

            Console.WriteLine("Elapsed Milliseconds List<> via foreach: {0}", sw.ElapsedMilliseconds);
        }

        static void Test6(ushort[] arr)
        {
            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();

            sw.Start();
            Test.SumSpecial(arr); 
            sw.Stop();

            Console.WriteLine("Elapsed Milliseconds Array via special: {0}", sw.ElapsedMilliseconds);
        }

        static void Test7(List<ushort> lst)
        {
            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();

            sw.Start();
            Test.SumSpecial(lst); 
            sw.Stop();

            Console.WriteLine("Elapsed Milliseconds List<> via special: {0}", sw.ElapsedMilliseconds);
        }

    }
}