slink.H

/* Aleph-w

     / \  | | ___ _ __ | |__      __      __
    / _ \ | |/ _ \ '_ \| '_ \ ____\ \ /\ / / Data structures & Algorithms
   / ___ \| |  __/ |_) | | | |_____\ V  V /  version 1.9b
  /_/   \_\_|\___| .__/|_| |_|      \_/\_/   https://github.com/lrleon/Aleph-w
                 |_|         

  This file is part of Aleph-w library

  Copyright (c) 2002-2018 Leandro Rabindranath Leon & Alejandro Mujica

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program. If not, see <https://www.gnu.org/licenses/>.
*/

# 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() 
  {
    next = this; 
  }
  bool is_empty() const 
  {
    return next == this; 
  }

  Slink *& get_next() 
  {
    return next; 
  }

  void insert_next(Slink * p)
  {
    assert(p not_eq nullptr);
    assert(p->is_empty());

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

  Slink * remove_next()
  {
    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 */