An explorative peek into generating deterministic primes through a multi-level multi-language tunneling apparatus

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This article was written as a joke for April Fools Day 2010. Readers are advised not to take the contents of this article too seriously.

Introduction

This paper is a summary of a research exercise conducted in conjunction by Nish Sivakumar, Professor Cuthbert Calculus, and Glenn Quagmire. The paper describes an explorative peek into generating deterministic primes through a multi-level multi-language tunneling apparatus. The example code is kept simple enough so as to keep focus on the fundamental problem we are attempting to solve. At the core, we start off with an inline assembler method consumed by an exported C function, wrapped and exported as a C++ class that's then consumed and exposed to the CLR through a C++/CLI wrapper, which is then used by a C# COM DLL that exposes an interface that is consumed through VBScript and executed through a command scriplet. 

Inline assembly

int GenerateIndex(int num)
{
  _asm
  {
    mov eax, dword ptr [num]
    xor edx, edx
    mov ecx, 3
    idiv ecx
    mov eax, edx
  }
}

This is the core randomization code and it's in assembly to keep things simple and lightweight. In the example we restrict the number of cached prime numbers to 3 and hence the divisor in the code.

C DLL Export

int __stdcall DllMain()
{ 
  return 0;
}

int primes[] = { 29, 37, 61 };

__declspec(dllexport) int GetDetPrime()
{
  return primes[GenerateIndex(GetTickCount())];
}

The C DLL essentially exports a simple function that returns a deterministic prime, and the code internally delegates the randomization logic to the assembler code. At this point the library is consumable by any framework or layer capable of calling a C DLL.

C++ class Export

// The header file
class __declspec(dllexport) CDetPrimeLib 
{
public:
  int GetDetPrime();
};

// Implementation file
#pragma comment(lib, "DetPrime.lib")

extern "C" __declspec(dllimport) int GetDetPrime();

int CDetPrimeLib::GetDetPrime()
{
  return ::GetDetPrime();
}

Here we wrap the C DLL and export it as a C++ class to natively support the most popular programming language in the world. It's a very thin wrapper since we don't want to add any overhead at this point.

CLI wrapper using C++/CLI

#pragma once

#pragma comment(lib, "DetPrimeLib.lib")

class __declspec(dllimport) CDetPrimeLib 
{
public:
  int GetDetPrime();
};

namespace DetPrimeManWrap 
{
  public ref class DetPrimeManaged
  {
    CDetPrimeLib* pNative;

  public:
    DetPrimeManaged()
    {
      pNative = new CDetPrimeLib();
    }

    ~DetPrimeManaged()
    {
      this->!DetPrimeManaged();
    }

    !DetPrimeManaged()
    {
      delete pNative;
    }

    int GetDetPrime()
    {
      return pNative->GetDetPrime();
    }
  };
}

While we have already provided enough API exposure to be considered mainstream, it makes good sense to also directly support .NET and thus we have a C++/CLI wrapper library that exposes the functionality to managed callers.

COM wrapper using C#

[assembly: ComVisible(true)]
[assembly: Guid("6b4bf847-a45d-4f87-ba53-0d4a9fffa975")]
[assembly: AssemblyVersion("1.0.1.1")]
[assembly: AssemblyFileVersion("1.0.1.1")]

namespace DetPrimeCOM
{
    using DetPrimeManWrap;

    [Guid("18535B5E-0561-4BA8-8CF6-85B148F3A4CF")]
    [ComVisible(true)]
    [InterfaceType(ComInterfaceType.InterfaceIsDual)]
    public interface IDetPrime
    {
        int GetDetPrime();
    }

    [Guid("2299461C-1FFB-4D5D-A521-0830F93FB5CC")]
    [ComVisible(true)]
    [ClassInterface(ClassInterfaceType.AutoDual)]
    public class DetPrime : IDetPrime
    {
        public int GetDetPrime()
        {
            return new DetPrimeManaged().GetDetPrime();
        }
    }
}

Since we support .NET we may as well support COM too and that's what the above C# code does. The code is now ready for COM consumption.

VBScript caller

Dim detPrime 
Set detPrime = CreateObject("DetPrimeCOM.DetPrime")
Wscript.Echo "The generated Deterministic Prime is " & detPrime.GetDetPrime

VB6 is now officially extinct and so we resort to a simple VBScript script to invoke the COM library.

Command scriplet

@%windir%\syswow64\cscript.exe /nologo DetPrime.vbs

And the last piece in our architecture is the command scriplet which executes the VBScript through cscript.exe so we can run it on a 64 bit OS, even though the code is 32 bit to support the vast majority of frameworks out there.

Conclusion

This article was written as a joke for April Fools Day 2010. Readers are advised not to take the contents of this article too seriously.