code.delx.au - pulseaudio/blob - src/polypcore/llist.h

   1 #ifndef foollistfoo
   2 #define foollistfoo
   3
   4 /* $Id$ */
   5
   6 /***
   7   This file is part of polypaudio.
   8
   9   polypaudio is free software; you can redistribute it and/or modify
  10   it under the terms of the GNU Lesser General Public License as
  11   published by the Free Software Foundation; either version 2 of the
  12   License, or (at your option) any later version.
  13
  14   polypaudio is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public
  20   License along with polypaudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 /* Some macros for maintaining doubly linked lists */
  26
  27 /* The head of the linked list. Use this in the structure that shall
  28  * contain the head of the linked list */
  29 #define PA_LLIST_HEAD(t,name) t *name
  30
  31 /* The pointers in the linked list's items. Use this in the item structure */
  32 #define PA_LLIST_FIELDS(t) t *next, *prev
  33
  34 /* Initialize the list's head */
  35 #define PA_LLIST_HEAD_INIT(t,item) do { (item) = NULL; } while(0)
  36
  37 /* Initialize a list item */
  38 #define PA_LLIST_INIT(t,item) do { \
  39                                t *_item = (item); \
  40                                assert(_item); \
  41                                _item->prev = _item->next = NULL; \
  42                                } while(0)
  43
  44 /* Prepend an item to the list */
  45 #define PA_LLIST_PREPEND(t,head,item) do { \
  46                                         t **_head = &(head), *_item = (item); \
  47                                         assert(_item); \
  48                                         if ((_item->next = *_head)) \
  49                                            _item->next->prev = _item; \
  50                                         _item->prev = NULL; \
  51                                         *_head = _item; \
  52                                         } while (0)
  53
  54 /* Remove an item from the list */
  55 #define PA_LLIST_REMOVE(t,head,item) do { \
  56                                     t **_head = &(head), *_item = (item); \
  57                                     assert(_item); \
  58                                     if (_item->next) \
  59                                        _item->next->prev = _item->prev; \
  60                                     if (_item->prev) \
  61                                        _item->prev->next = _item->next; \
  62                                     else {\
  63                                        assert(*_head == _item); \
  64                                        *_head = _item->next; \
  65                                     } \
  66                                     _item->next = _item->prev = NULL; \
  67                                     } while(0)
  68
  69 #define PA_LLIST_FIND_HEAD(t,item,head) \
  70 do { \
  71     t **_head = (head), *_item = (item); \
  72     *_head = _item; \
  73     assert(_head); \
  74     while ((*_head)->prev) \
  75         *_head = (*_head)->prev; \
  76 } while (0) \
  77
  78
  79 #endif