source4/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 do { \
  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 } while (0)
  38
  39 /* remove an element from a list - element doesn't have to be in list. */
  40 #define DLIST_REMOVE(list, p) \
  41 do { \
  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 } while (0)
  51
  52 /* promote an element to the top of the list */
  53 #define DLIST_PROMOTE(list, p) \
  54 do { \
  55           DLIST_REMOVE(list, p); \
  56           DLIST_ADD(list, p); \
  57 } while (0)
  58
  59 /* hook into the end of the list - needs a tmp pointer */
  60 #define DLIST_ADD_END(list, p, type) \
  61 do { \
  62                 if (!(list)) { \
  63                         (list) = (p); \
  64                         (p)->next = (p)->prev = NULL; \
  65                 } else { \
  66                         type tmp; \
  67                         for (tmp = (list); tmp->next; tmp = tmp->next) ; \
  68                         tmp->next = (p); \
  69                         (p)->next = NULL; \
  70                         (p)->prev = tmp; \
  71                 } \
  72 } while (0)
  73
  74 /* insert 'p' after the given element 'el' in a list. If el is NULL then
  75    this is the same as a DLIST_ADD() */
  76 #define DLIST_ADD_AFTER(list, p, el) \
  77 do { \
  78         if (!(list) || !(el)) { \
  79                 DLIST_ADD(list, p); \
  80         } else { \
  81                 p->prev = el; \
  82                 p->next = el->next; \
  83                 el->next = p; \
  84                 if (p->next) p->next->prev = p; \
  85         }\
  86 } while (0)
  87
  88 /* demote an element to the end of the list, needs a tmp pointer */
  89 #define DLIST_DEMOTE(list, p, tmp) \
  90 do { \
  91                 DLIST_REMOVE(list, p); \
  92                 DLIST_ADD_END(list, p, tmp); \
  93 } while (0)
  94
  95 /* concatenate two lists - putting all elements of the 2nd list at the
  96    end of the first list */
  97 #define DLIST_CONCATENATE(list1, list2, type) \
  98 do { \
  99                 if (!(list1)) { \
 100                         (list1) = (list2); \
 101                 } else { \
 102                         type tmp; \
 103                         for (tmp = (list1); tmp->next; tmp = tmp->next) ; \
 104                         tmp->next = (list2); \
 105                         if (list2) { \
 106                                 (list2)->prev = tmp;    \
 107                         } \
 108                 } \
 109 } while (0)