NTFSSecurity/Security2/Extensions.cs

using System;
using System.Runtime.InteropServices;

namespace Security2
{
    internal static class IntPtrExtensions
    {
        public static IntPtr Increment(this IntPtr ptr, int cbSize)
        {
            return new IntPtr(ptr.ToInt64() + cbSize);
        }

        public static IntPtr Increment<T>(this IntPtr ptr)
        {
            return ptr.Increment(Marshal.SizeOf(typeof(T)));
        }

        public static T ElementAt<T>(this IntPtr ptr, int index)
        {
            var offset = Marshal.SizeOf(typeof(T)) * index;
            var offsetPtr = ptr.Increment(offset);
            return (T)Marshal.PtrToStructure(offsetPtr, typeof(T));
        }
    }
}