/*

 * lftp - file transfer program

 *

 * Copyright (c) 1996-2013 by Alexander V. Lukyanov (lav@yars.free.net)

 *

 * 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 <http://www.gnu.org/licenses/>.

 */

#ifndef XLIST_H

#define XLIST_H 1

// this list implementation is based on linux kernel idea of lists

#include <stddef.h>

#include <assert.h>

template<class T> class xlist

{

   xlist<T> *next;

   xlist<T> *prev;

   T *obj;

   static void _add(xlist<T> *node,xlist<T> *prev,xlist<T> *next) {

      next->prev=node;

      node->next=next;

      node->prev=prev;

      prev->next=node;

   }

   static void _del(xlist<T> *prev,xlist<T> *next) {

      next->prev=prev;

      prev->next=next;

   }

protected:

   xlist() : next(this), prev(this), obj(0) {}

public:

   xlist(T *t) : next(0), prev(0), obj(t) {}

   void add(xlist<T> *node) {

      assert(!node->next && !node->prev);

      _add(node,this,next);

   }

   void add(xlist<T>& node) { add(&node); }

   void add_tail(xlist<T> *node) {

      assert(!node->next && !node->prev);

      _add(node,prev,this);

   }

   void add_tail(xlist<T>& node) { add_tail(&node); }

   void remove() {

      _del(prev,next);

      next=prev=0;

   }

   xlist<T> *get_next() const { return next; }

   xlist<T> *get_prev() const { return prev; }

   T *get_obj() const { return obj; }

   T *next_obj() const { return next->obj; }

   int count() const {

      int count=0;

      for(xlist<T> *scan=next; scan!=this; scan=scan->next)

	 count++;

      return count;

   }

   bool listed() const {

      return next!=0;

   }

};

template<class T> class xlist_head : public xlist<T>

{

public:

   xlist_head() {}

   T *first_obj() const { return xlist<T>::next_obj(); }

};

#define xlist_for_each(TYPE,list_head,node,obj) \

   TYPE *obj; \

   for(xlist<TYPE> *node=(list_head).get_next(); obj=node->get_obj(), node!=&list_head; node=node->get_next())

#define xlist_for_each_safe(TYPE,list_head,node,obj,next) \

   TYPE *obj; \

   for(xlist<TYPE> *node=(list_head).get_next(), *next=node->get_next(); obj=node->get_obj(), node!=&list_head; node=next, next=node->get_next())

#endif//XLIST_H