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