#include <iostream>

#include "TClonesArray.h"
#include "TObject.h"
#include "TError.h"
#include "Rtypes.h"

const unsigned nComponents = 10;
const unsigned nParticles = 100;

struct Particle : TObject
{
   double data_[nComponents];
   ClassDef(Particle, 0)
};

ClassImp(Particle)

struct Event : TObject
{
   Event();
   ~Event();
   void AddParticle(const double *data);
   void Clear(Option_t * opt);

   unsigned nActive_;
   TClonesArray particles_;
   
   ClassDef(Event, 0)
};

ClassImp(Event)

//______________________________________________
Event::Event()
         : nActive_(0),
           particles_("Particle", nParticles)
{
   std::cout<<"Event::Event(), this == "<<this<<std::endl;
}

//______________________________________________
Event::~Event()
{
   std::cout<<"Event::~Event(), this == "<<this<<std::endl;
}

//______________________________________________
void Event::AddParticle(const double *data)
{
   if (!data)
   {//A very primitive test.
      Error("AddParticle", "invalid pointer");
      return;
   }
   
   Particle * const p = static_cast<Particle *>(particles_.ConstructedAt(nActive_++));
   for (unsigned i = 0; i < nComponents; ++i)
      p->data_[i] = data[i];
}

//______________________________________________
void Event::Clear(Option_t * /*not used*/)
{
   particles_.Clear("C");
   nActive_ = 0;
}

//______________________________________________
void cla()
{
   //Test.
   const unsigned int nEvents = 10;
   TClonesArray events("Event", nEvents);
   double dummy[nComponents] = {};
   while (true)
   {
      for (unsigned i = 0; i < 1000; ++i)
      {
         for (unsigned j = 0; j < nEvents; ++j)
         {
            Event * const newEvent = static_cast<Event *>(events.ConstructedAt(j));//Create or reuse.
            for (unsigned k = 0; k < nParticles; ++k)
               newEvent->AddParticle(dummy);
         }
         events.Clear("C");
      }
      
      char c = 0;
      std::cout<<"Enough?\n";
      std::cin>>c;
      if (c == 'y')
         break;
   }
}