text: /*
   * dlist.h
   * - macros for handling doubly linked lists
   */
  /*
   *  This file is
   *    Copyright (C) 1997-1999 Ian Jackson <ian@davenant.greenend.org.uk>
   *
   *  It is part of adns, which is
   *    Copyright (C) 1997-2000 Ian Jackson <ian@davenant.greenend.org.uk>
   *    Copyright (C) 1999 Tony Finch <dot@dotat.at>
   *  
   *  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 2, 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, write to the Free Software Foundation,
   *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 
   */
  
  #ifndef ADNS_DLIST_H_INCLUDED
  #define ADNS_DLIST_H_INCLUDED
  
  #define LIST_INIT(list) ((list).head= (list).tail= 0)
  #define LINK_INIT(link) ((link).next= (link).back= 0)
  
  #define LIST_UNLINK_PART(list,node,part) \
    do { \
      if ((node)->part back) (node)->part back->part next= (node)->part next; \
        else                                  (list).head= (node)->part next; \
      if ((node)->part next) (node)->part next->part back= (node)->part back; \
        else                                  (list).tail= (node)->part back; \
    } while(0)
  
  #define LIST_LINK_TAIL_PART(list,node,part) \
    do { \
      (node)->part next= 0; \
      (node)->part back= (list).tail; \
      if ((list).tail) (list).tail->part next= (node); else (list).head= (node); \
      (list).tail= (node); \
    } while(0)
  
  #define LIST_UNLINK(list,node) LIST_UNLINK_PART(list,node,)
  #define LIST_LINK_TAIL(list,node) LIST_LINK_TAIL_PART(list,node,)
  
  #endif
  