Alloc example about keralua HOT 3 CLOSED

using System;
using System.Runtime.InteropServices;
using KeraLua;

namespace ConsoleApp1
{
    class Program
    {
        private  static readonly uint LimitMemory = 4000;

        private static uint _memory = 0;
        private static uint MemoryInUse
        {
            get => _memory;
            set
            {
                if (value > LimitMemory)
                    _lua.Error("Memory overflow");
                _memory = value;
            }
        }
        private static Lua _lua;
        static void Main(string[] args)
        {
            LuaAlloc myAlloc = MyAlloc;
            _lua = new Lua(myAlloc, IntPtr.Zero);
            bool res = _lua.DoString("x = 10* 10");
            res = _lua.DoString("x = 10* 10");
            res = _lua.DoString("x = 10* 10");
            res = _lua.DoString("x = 10* 10");
            _lua.GetGlobal("x");
            long x = _lua.ToInteger(-1);
        }

        private static IntPtr MyAlloc(IntPtr ud, IntPtr ptr, UIntPtr osize, UIntPtr nsize)
        {
            if (osize == nsize)
                return ptr;

            uint newSize = nsize.ToUInt32();

            if (nsize == UIntPtr.Zero)
            {
                Marshal.FreeHGlobal(ptr);

                MemoryInUse -= newSize;

                return IntPtr.Zero;
            }

            if (ptr == IntPtr.Zero)
            {
                MemoryInUse += newSize;
                return Marshal.AllocHGlobal((IntPtr) newSize);
            }

            return Marshal.ReAllocHGlobal(ptr, (IntPtr) newSize);
        }
    }
}