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

   1 #ifndef foollistfoo
   2 #define foollistfoo
   3
   4 /* $Id$ */
   5
   6 /***
   7   This file is part of PulseAudio.
   8
   9   Copyright 2004-2006 Lennart Poettering
  10
  11   PulseAudio is free software; you can redistribute it and/or modify
  12   it under the terms of the GNU Lesser General Public License as
  13   published by the Free Software Foundation; either version 2 of the
  14   License, or (at your option) any later version.
  15
  16   PulseAudio is distributed in the hope that it will be useful, but
  17   WITHOUT ANY WARRANTY; without even the implied warranty of
  18   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19   General Public License for more details.
  20
  21   You should have received a copy of the GNU Lesser General Public
  22   License along with PulseAudio; if not, write to the Free Software
  23   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  24   USA.
  25 ***/
  26
  27 #include <pulsecore/macro.h>
  28
  29 /* Some macros for maintaining doubly linked lists */
  30
  31 /* The head of the linked list. Use this in the structure that shall
  32  * contain the head of the linked list */
  33 #define PA_LLIST_HEAD(t,name)                                           \
  34     t *name
  35
  36 /* The pointers in the linked list's items. Use this in the item structure */
  37 #define PA_LLIST_FIELDS(t)                                              \
  38     t *next, *prev
  39
  40 /* Initialize the list's head */
  41 #define PA_LLIST_HEAD_INIT(t,item)                                      \
  42     do {                                                                \
  43         (item) = (t*) NULL; }                                           \
  44     while(0)
  45
  46 /* Initialize a list item */
  47 #define PA_LLIST_INIT(t,item)                                           \
  48     do {                                                                \
  49         t *_item = (item);                                              \
  50         pa_assert(_item);                                               \
  51         _item->prev = _item->next = NULL;                               \
  52     } while(0)
  53
  54 /* Prepend an item to the list */
  55 #define PA_LLIST_PREPEND(t,head,item)                                   \
  56     do {                                                                \
  57         t **_head = &(head), *_item = (item);                           \
  58         pa_assert(_item);                                               \
  59         if ((_item->next = *_head))                                     \
  60             _item->next->prev = _item;                                  \
  61         _item->prev = NULL;                                             \
  62         *_head = _item;                                                 \
  63     } while (0)
  64
  65 /* Remove an item from the list */
  66 #define PA_LLIST_REMOVE(t,head,item)                                    \
  67     do {                                                                \
  68         t **_head = &(head), *_item = (item);                           \
  69         pa_assert(_item);                                               \
  70         if (_item->next)                                                \
  71             _item->next->prev = _item->prev;                            \
  72         if (_item->prev)                                                \
  73             _item->prev->next = _item->next;                            \
  74         else {                                                          \
  75             pa_assert(*_head == _item);                                 \
  76             *_head = _item->next;                                       \
  77         }                                                               \
  78         _item->next = _item->prev = NULL;                               \
  79     } while(0)
  80
  81 /* Find the head of the list */
  82 #define PA_LLIST_FIND_HEAD(t,item,head)                                 \
  83     do {                                                                \
  84         t **_head = (head), *_item = (item);                            \
  85         *_head = _item;                                                 \
  86         pa_assert(_head);                                               \
  87         while ((*_head)->prev)                                          \
  88             *_head = (*_head)->prev;                                    \
  89     } while (0)
  90
  91 /* Insert an item after another one (a = where, b = what) */
  92 #define PA_LLIST_INSERT_AFTER(t,head,a,b)                               \
  93     do {                                                                \
  94         t **_head = &(head), *_a = (a), *_b = (b);                      \
  95         pa_assert(_b);                                                  \
  96         if (!_a) {                                                      \
  97             if ((_b->next = *_head))                                    \
  98                 _b->next->prev = _b;                                    \
  99             _b->prev = NULL;                                            \
 100             *_head = _b;                                                \
 101         } else {                                                        \
 102             if ((_b->next = _a->next))                                  \
 103                 _b->next->prev = _b;                                    \
 104             _b->prev = _a;                                              \
 105             _a->next = _b;                                              \
 106         }                                                               \
 107     } while (0)
 108
 109 #endif