// this is based on item 10 from Scott Meyers "Effective C++"
#include <new>
#include <string>
#include <iostream>

using namespace std;

class AirplaneRep {
protected:
  string _name;
  long _weight;
  
public:
  static long count;

  AirplaneRep( const std::string& name="", long weight=0) : _name( name), _weight(weight) {
    count ++;
  }

  void Name( const string& name) {
    _name = name;
  }

  const string& Name() const {
    return _name;
  }

  void Weight( long weight) {
    _weight = weight;
  }

  const long Weight() const {
    return _weight;
  }

  virtual ~AirplaneRep() {
    count--;
  }
};

long AirplaneRep::count;

class Airplane : public AirplaneRep {
private:
  AirplaneRep *rep;
  static Airplane *headOfFreeList;
public:
  void *operator new( size_t size) throw();
  void operator delete( void *deadObject, size_t size);

  Airplane( const std::string& name="", long weight=0) : AirplaneRep( name, weight) { }

};

Airplane *Airplane::headOfFreeList = 0;

void *Airplane::operator new(size_t size) throw() {
  if (size != sizeof(Airplane)) {
    return ::new char[size];
  }

  Airplane *p = headOfFreeList;

  if (p)
    headOfFreeList = (Airplane*)p->rep;

  else {
    Airplane *newBlock =
      (Airplane *) ::new(std::nothrow) char[256*sizeof(Airplane)];
    
    if (newBlock==0) return 0;

    int i;
    for (i=0; i<255; i++) {
      newBlock[i].rep = (AirplaneRep*) &newBlock[i+1];
    }

    newBlock[i].rep = 0;

    p = newBlock;
    headOfFreeList = &newBlock[1];
  }

  return p;
}

void Airplane::operator delete (void* deadObject, size_t size)
{
  if (size != sizeof(Airplane)) {
    ::delete [] ((char*)deadObject);
    return;
  }

  Airplane *carcass = (Airplane*) deadObject;
  carcass->rep = (AirplaneRep*) headOfFreeList;
  headOfFreeList = carcass;
}

int main() {
  long i;
  Airplane *ap[100];

  for (i=0;i<100;i++) {
    ap[i] = new Airplane();
    cout << "count = " << AirplaneRep::count << endl;
  }

  for (i=0;i<100;i++) {
    delete ap[i];
    cout << "count = " << AirplaneRep::count << endl;
  }

  return 0;
}