lib/util/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 3 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, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 /* To use these macros you must have a structure containing a next and
  21    prev pointer */
  22
  23 #ifndef _DLINKLIST_H
  24 #define _DLINKLIST_H
  25
  26
  27 /* hook into the front of the list */
  28 #define DLIST_ADD(list, p) \
  29 do { \
  30         if (!(list)) { \
  31                 (list) = (p); \
  32                 (p)->next = (p)->prev = NULL; \
  33         } else { \
  34                 (list)->prev = (p); \
  35                 (p)->next = (list); \
  36                 (p)->prev = NULL; \
  37                 (list) = (p); \
  38         }\
  39 } while (0)
  40
  41 /* remove an element from a list - element doesn't have to be in list. */
  42 #define DLIST_REMOVE(list, p) \
  43 do { \
  44         if ((p) == (list)) { \
  45                 (list) = (p)->next; \
  46                 if (list) (list)->prev = NULL; \
  47         } else { \
  48                 if ((p)->prev) (p)->prev->next = (p)->next; \
  49                 if ((p)->next) (p)->next->prev = (p)->prev; \
  50         } \
  51         if ((p) != (list)) (p)->next = (p)->prev = NULL; \
  52 } while (0)
  53
  54 /* promote an element to the top of the list */
  55 #define DLIST_PROMOTE(list, p) \
  56 do { \
  57           DLIST_REMOVE(list, p); \
  58           DLIST_ADD(list, p); \
  59 } while (0)
  60
  61 /* hook into the end of the list - needs the entry type */
  62 #define DLIST_ADD_END(list, p, type) \
  63 do { \
  64                 if (!(list)) { \
  65                         (list) = (p); \
  66                         (p)->next = (p)->prev = NULL; \
  67                 } else { \
  68                         type tmp; \
  69                         for (tmp = (list); tmp->next; tmp = tmp->next) ; \
  70                         tmp->next = (p); \
  71                         (p)->next = NULL; \
  72                         (p)->prev = tmp; \
  73                 } \
  74 } while (0)
  75
  76 /* insert 'p' after the given element 'el' in a list. If el is NULL then
  77    this is the same as a DLIST_ADD() */
  78 #define DLIST_ADD_AFTER(list, p, el) \
  79 do { \
  80         if (!(list) || !(el)) { \
  81                 DLIST_ADD(list, p); \
  82         } else { \
  83                 p->prev = el; \
  84                 p->next = el->next; \
  85                 el->next = p; \
  86                 if (p->next) p->next->prev = p; \
  87         }\
  88 } while (0)
  89
  90 /* demote an element to the end of the list, needs a tmp pointer */
  91 #define DLIST_DEMOTE(list, p, tmp) \
  92 do { \
  93                 DLIST_REMOVE(list, p); \
  94                 DLIST_ADD_END(list, p, tmp); \
  95 } while (0)
  96
  97 /* concatenate two lists - putting all elements of the 2nd list at the
  98    end of the first list */
  99 #define DLIST_CONCATENATE(list1, list2, type) \
 100 do { \
 101                 if (!(list1)) { \
 102                         (list1) = (list2); \
 103                 } else { \
 104                         type tmp; \
 105                         for (tmp = (list1); tmp->next; tmp = tmp->next) ; \
 106                         tmp->next = (list2); \
 107                         if (list2) { \
 108                                 (list2)->prev = tmp;    \
 109                         } \
 110                 } \
 111 } while (0)
 112
 113 #endif /* _DLINKLIST_H */