source/include/dlinklist.h

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    some simple double linked list macros
   5    Copyright (C) Andrew Tridgell 1998
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 /* To use these macros you must have a structure containing a next and
  23    prev pointer */
  24
  25
  26 /* hook into the front of the list */
  27 #define DLIST_ADD(list, p) \
  28 { \
  29         if (!(list)) { \
  30                 (list) = (p); \
  31                 (p)->next = (p)->prev = NULL; \
  32         } else { \
  33                 (list)->prev = (p); \
  34                 (p)->next = (list); \
  35                 (p)->prev = NULL; \
  36                 (list) = (p); \
  37         }\
  38 }
  39
  40
  41 /* remove an element from a list */
  42 #define DLIST_REMOVE(list, p) \
  43 { \
  44         if ((p) == (list)) { \
  45                 (list) = (p)->next; \
  46                 if (list) (list)->prev = NULL; \
  47         } else { \
  48                 (p)->prev->next = (p)->next; \
  49                 if ((p)->next) (p)->next->prev = (p)->prev; \
  50         } \
  51 }
  52
  53 /* promote an element to the top of the list */
  54 #define DLIST_PROMOTE(list, p) \
  55           DLIST_REMOVE(list, p) \
  56           DLIST_ADD(list, p)