Priority Queues

Any class prio_impl that provides the following operations can be used as actual implementation parameter for the _priority_queue< K,I,prio_impl> data type (cf. section Priority Queues).

typedef ... prio_impl_item;

class prio_impl $\{$ 

  virtual int  cmp(GenPtr, GenPtr) const = 0;
  virtual int  int_type()          const = 0;
  virtual void clear_key(GenPtr&)  const = 0;
  virtual void clear_inf(GenPtr&)  const = 0;
  virtual void copy_key(GenPtr&)   const = 0;
  virtual void copy_inf(GenPtr&)  const = 0;

public:

  prio_impl();
  prio_impl(int);
  prio_impl(int,int);
  prio_impl(const prio_impl&);
  virtual ~prio_impl();

  prio_impl& operator=(const prio_impl&);

  prio_impl_item insert(GenPtr,GenPtr);
  prio_impl_item find_min() \ const;
  prio_impl_item first_item() const;
  prio_impl_item next_item(prio_impl_item) const;

  prio_impl_item item(void* p) const 
  { return prio_impl_item(p); }
 
  GenPtr key(prio_impl_item) const;
  GenPtr inf(prio_impl_item) const;

  void del_min();
  void del_item(prio_impl_item);
  void decrease_key(prio_impl_item,GenPtr);
  void change_inf(prio_impl_item,GenPtr);
  void clear();
  
  int  size()  const;
};