/*
  * circular list maintenance macros
  *
  * Copyright (C) 2005 iptelorg GmbH
  *

  * This file is part of Kamailio, a free SIP server.

  *

  * Kamailio 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 2 of the License, or
  * (at your option) any later version
  *

  * Kamailio 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, write to the Free Software 

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

  */
 

 /*!
  * \file

  * \brief Kamailio core :: circular list maintenance macros

  *

  * \author andrei

  * \ingroup core
  * Module: \ref core
  */
 

 
 #ifndef _clist_h
 #define _clist_h
 

 /*! \brief circular list */

 #define clist_init(c, next, prev) \
 	do{ \

 		(c)->next=(void*)(c); \
 		(c)->prev=(void*)(c); \

 	} while(0)
 
 
 

 /*! \brief adds an entire sublist { s,e } (including s & e )

  * after head

  *
  * \note WARNING: clist_insert_sublist(head, n, n->prev) won't work,

  *          same for clist_insert_sublist(head, n->next, n)
  *  (macro!), use  e=n->prev; clist_insert_sublist(head, n, e, ...)
  *  instead!

  */
 #define clist_insert_sublist(head, s, e, next, prev) \
 	do{ \

 		(s)->prev=(void*)(head); \

 		(e)->next=(head)->next; \
 		(e)->next->prev=(e); \
 		(head)->next=s;   \
 	}while(0)
 
 
 

 /*! \brief appends an entire sublist { s,e } (including s & e )

  * at the end of the list

  *

  * WARNING: clist_append_sublist(head, n, n->prev, ...) won't work,
  *  (macro!), use  e=n->prev; clist_append_sublist(head, n, e, ...)
  *  instead!

  */
 #define clist_append_sublist(head, s, e, next, prev) \
 	do{ \
 		(s)->prev=(head)->prev; \
 		(e)->next=(void*)(head); \
 		(s)->prev->next=(s); \
 		(head)->prev=(e);   \
 	}while(0)
 
 
 

 /*! \brief remove sublist { s,e } (including s & e )

  * always, if start is the beginning of the list use

  * clist_rm_sublist(head->next, e, next, prev )
  * WARNING: clist_rm_sublist(n, n->prev, ...) won't work,
  *  (macro!), use  e=n->prev; clist_rm_sublist(n, e, ...)
  *  instead! */

 #define clist_rm_sublist(s, e, next, prev) \
 	do{\

 		(s)->prev->next=(e)->next;  \

 		(e)->next->prev=(s)->prev;  \
 		(s)->prev=NULL; \
 		(e)->next=NULL; \

 	}while(0)
 
 
 

 /*! \brief insert after (head) */

 #define clist_insert(head, c, next, prev) \
 	clist_insert_sublist(head, c, c, next, prev)
 
 
 

 /*! \brief  append at the end of the list (head->prev) */

 #define clist_append(head, c, next, prev) \
 	clist_append_sublist(head, c, c, next, prev)
 
 
 

 /*! \brief  remove and element */

 #define clist_rm(c, next, prev) \
 	clist_rm_sublist(c, c, next, prev)
 
 
 

 /*! \brief  iterate on a clist */

 #define clist_foreach(head, v, dir) \
 	for((v)=(head)->dir; (v)!=(void*)(head); (v)=(v)->dir)
 

 /*! \brief  iterate on a clist, safe version (requires an extra bak. var)

  * (it allows removing of the current element) */
 #define clist_foreach_safe(head, v, bak,  dir) \
 	for((v)=(head)->dir, (bak)=(v)->dir; (v)!=(void*)(head); \
 				(v)=(bak), (bak)=(v)->dir)
 #endif