slink.H

# ifndef SLINK_H
# define SLINK_H

# include <aleph.H>

using namespace Aleph;

namespace Aleph {

class Slink
{
protected:

    Slink * next;

public:

  Slink() : next(this) { /* Empty */ }

  void reset() 
  {
    I(this not_eq NULL);

    next = this; 
  }
  bool is_empty() const 
  {
    I(this not_eq NULL);

    return next == this; 
  }

  Slink *& get_next() 
  {
    I(this not_eq NULL);
    return next; 
  }

  void insert_next(Slink * p)
  {

    I(this not_eq NULL);
    I(p not_eq NULL);
    I(p->is_empty());

    p->next = next;
    next = p;
  }

  Slink * remove_next()
  {
    I(this not_eq NULL);

    Slink * ret_val = next;
    next = ret_val->next;
    ret_val->reset();
    return ret_val;
  }    
};
# define SLINK_TO_TYPE(type_name, link_name)                            \
  static type_name * slink_to_type(Slink * link)                        \
  {                                                                     \
    type_name * ptr_zero = 0;                                           \
    size_t offset_link = (size_t) &(ptr_zero->link_name);               \
    unsigned long address_type = ((unsigned long) link) - offset_link;  \
    return (type_name *) address_type;                                  \
  } 

} // end namespace Aleph
# endif /* SLINK_H */