source3/include/dlinklist.h

   1 /*
   2    Unix SMB/CIFS implementation.
   3    some simple double linked list macros
   4    Copyright (C) Andrew Tridgell 1998
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19 */
  20
  21 /* To use these macros you must have a structure containing a next and
  22    prev pointer */
  23
  24
  25 /* hook into the front of the list */
  26 #define DLIST_ADD(list, p) \
  27 { \
  28         if (!(list)) { \
  29                 (list) = (p); \
  30                 (p)->next = (p)->prev = NULL; \
  31         } else { \
  32                 (list)->prev = (p); \
  33                 (p)->next = (list); \
  34                 (p)->prev = NULL; \
  35                 (list) = (p); \
  36         }\
  37 }
  38
  39 /* remove an element from a list - element doesn't have to be in list. */
  40 #define DLIST_REMOVE(list, p) \
  41 { \
  42         if ((p) == (list)) { \
  43                 (list) = (p)->next; \
  44                 if (list) (list)->prev = NULL; \
  45         } else { \
  46                 if ((p)->prev) (p)->prev->next = (p)->next; \
  47                 if ((p)->next) (p)->next->prev = (p)->prev; \
  48         } \
  49         if ((p) && ((p) != (list))) (p)->next = (p)->prev = NULL; \
  50 }
  51
  52 /* promote an element to the top of the list */
  53 #define DLIST_PROMOTE(list, p) \
  54 { \
  55           DLIST_REMOVE(list, p) \
  56           DLIST_ADD(list, p) \
  57 }
  58
  59 /* hook into the end of the list - needs a tmp pointer */
  60 #define DLIST_ADD_END(list, p, tmp) \
  61 { \
  62                 if (!(list)) { \
  63                         (list) = (p); \
  64                         (p)->next = (p)->prev = NULL; \
  65                 } else { \
  66                         for ((tmp) = (list); (tmp)->next; (tmp) = (tmp)->next) ; \
  67                         (tmp)->next = (p); \
  68                         (p)->next = NULL; \
  69                         (p)->prev = (tmp); \
  70                 } \
  71 }
  72
  73 /* demote an element to the top of the list, needs a tmp pointer */
  74 #define DLIST_DEMOTE(list, p, tmp) \
  75 { \
  76                 DLIST_REMOVE(list, p) \
  77                 DLIST_ADD_END(list, p, tmp) \
  78 }