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Session of low-level optimization of memory usage in C++ programs with total exposure

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22 Jun 2009CPOL7 min read 39.6K   246   44  
In this article, we will try to make our algorithms work faster using the methods of low-level optimization of memory allocation in C++.
#include "cmnFastObjects.h"
#include "string"
#include "iostream"
#include "memory"
#include "windows.h"

// mega factory
struct ISomethingAbstract
{
    virtual ~ISomethingAbstract(){}
    virtual void DoIt()=0;
    virtual void Validate(int iValue)=0;
};


class CObject1:public ISomethingAbstract
{
    int m_iCount;
public:
    CObject1()
        : m_iCount(0)
    {
        //std::cout<<"CObject2:CObject2 \n"; 
    }
    CObject1(const CObject1 & obj)
        : m_iCount(obj.m_iCount)
    {
        //std::cout<<"CObject2:CObject2(const CObject2 & obj) \n"; 
    }
    ~CObject1()
    {
        //std::cout<<"CObject2:~CObject2 \n"; 
    }
    virtual void DoIt() 
    {
        ++m_iCount;
        //std::cout<<"CObject2::DoIt\n"; 
    }
    virtual void Validate(int iValue)
    {
        if (m_iCount != iValue)
            abort();
    }
};

class CObject2:public ISomethingAbstract
{
    int m_iCount;
public:
    CObject2()
        : m_iCount(0)
    {
    }
    CObject2(const CObject2 & obj)
        : m_iCount(obj.m_iCount)
    {
    }
    ~CObject2()
    {
    }
    virtual void DoIt() 
    {
        ++m_iCount;
    }
    virtual void Validate(int iValue)
    {
        if (m_iCount != iValue)
            abort();
    }
};




class CFastConcreteFactory
{
public:
    typedef utils::Node<utils::manageable<CObject1, utils::allow_copy>, 
                 utils::Node<utils::manageable<CObject2, utils::allow_copy>, 
                      utils::NullNode
                     > 
                > ObjectList;

    static const size_t MaxObjectSize = utils::GetMaxSize<ObjectList>::Result;
    typedef utils::CFastObject<MaxObjectSize, ISomethingAbstract> AnyObject;

    void CreateSmth(int iValue, AnyObject * pResult)
    {
        if (iValue<0)
        {
            pResult->CreateByCopy(utils::manageable<CObject1, utils::allow_copy>());
        }
        else
        {
            pResult->CreateByCopy(utils::manageable<CObject2, utils::allow_copy>());
        }
    }
};

class CStandardFactory
{
public:
    void CreateSmth(int iValue, std::auto_ptr<ISomethingAbstract> * pResult)
    {
        if (iValue<0)
        {
            pResult->reset(new CObject1);
        }
        else
        {
            pResult->reset(new CObject2);
        }
    }
};

void RunUnitTests()
{
    CFastConcreteFactory factory;
    CFastConcreteFactory::AnyObject object2;
    factory.CreateSmth(-1, &object2);
    object2->DoIt();
    factory.CreateSmth(1, &object2);
    object2->DoIt();
   
    utils::CFastObject<50, std::string> object;
    utils::manageable<std::string, utils::allow_all> str("hello_world");
    object.CreateByCopy(str);
    
    // test initialization
    if (*object.GetInterface<std::string>() != "hello_world")
    {
        abort();
    }

    // test copy
    {
        utils::CFastObject<50, std::string> copy_of_object;
        object.Copy( &copy_of_object );
        if (*copy_of_object.GetInterface<std::string>() != "hello_world")
        {
            abort();
        }
    }

    // test move
    {
        utils::CFastObject<50, std::string> copy_of_object;
        object.Move( &copy_of_object );
        if (*copy_of_object.GetInterface<std::string>() != "hello_world")
        {
            abort();
        }
        if (!object.IsClean())
        {
            abort();
        }
    }
}


void RunPerformanceTests()
{
    const int iIterCount = 10000000;
    { // standard way
        Sleep(0);
        DWORD dwBegin = GetTickCount();

        CStandardFactory factory;
        std::auto_ptr<ISomethingAbstract> object2;
        for(int i =0;i<iIterCount;++i)
        {
            factory.CreateSmth(-1, &object2);
            object2->DoIt();
            object2->Validate(1);
        }
        
        DWORD dwEnd = GetTickCount();
        std::cout<<"Normal time: "<<dwEnd-dwBegin<<"\n";
    }

    { // optimized way
        Sleep(0);
        DWORD dwBegin = GetTickCount();

        CFastConcreteFactory factory;
        CFastConcreteFactory::AnyObject object2;
        for(int i =0;i<iIterCount;++i)
        {
            factory.CreateSmth(-1, &object2);
            object2->DoIt();
            object2->Validate(1);
        }
        DWORD dwEnd = GetTickCount();
        std::cout<<"FastObject time: "<<dwEnd-dwBegin<<"\n";
    }
}
int main()
{
    RunUnitTests();
    RunPerformanceTests();
    return 0;
}

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This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


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Chief Technology Officer Apriorit Inc.
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As Apriorit offers integrated research&development services for the software projects in such areas as endpoint security, network security, data security, embedded Systems, and virtualization, we have strong kernel and driver development skills, huge system programming expertise, and are reals fans of research projects.

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