Smart Pointers Reloaded (III): Construction

Listing 1: The original smart_ptr initialization mechanism.

ref_counted::ref_counted() {
   pCount_ = static_cast<unsigned int*>(
      SmallObject<>::operator new(sizeof(unsigned int)));
   assert(pCount_);
   *pCount_ = 1;
}

bool ref_counted::release(const P&) {
   if (!--*pCount_) {
      SmallObject<>::operator delete(pCount_, sizeof(unsigned int));
      return true;
   }
   return false;
}

class smart_ptr
   : public storage_policy<T>
   , public ownership_policy<typename storage_policy<T>::PointerType>
   , public checking_policy<typename storage_policy<T>::stored_type>
   , public conversion_policy
{ ... };

smart_ptr::smart_ptr(const stored_type& p) : SP(p)
{ KP::OnInit(GetImpl(*this)); }

smart_ptr::~smart_ptr() {
   if (OP::release(GetImpl(*static_cast<SP*>(this)))) {
      SP::Destroy();
   }
}