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

   1 #ifndef foollistfoo
   2 #define foollistfoo
   3
   4 /***
   5   This file is part of PulseAudio.
   6
   7   Copyright 2004-2006 Lennart Poettering
   8
   9   PulseAudio 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   PulseAudio 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 PulseAudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 #include <pulsecore/macro.h>
  26
  27 /* Some macros for maintaining doubly linked lists */
  28
  29 /* The head of the linked list. Use this in the structure that shall
  30  * contain the head of the linked list */
  31 #define PA_LLIST_HEAD(t,name)                                           \
  32     t *name
  33
  34 /* The pointers in the linked list's items. Use this in the item structure */
  35 #define PA_LLIST_FIELDS(t)                                              \
  36     t *next, *prev
  37
  38 /* Initialize the list's head */
  39 #define PA_LLIST_HEAD_INIT(t,item)                                      \
  40     do {                                                                \
  41         (item) = (t*) NULL; }                                           \
  42     while(0)
  43
  44 /* Initialize a list item */
  45 #define PA_LLIST_INIT(t,item)                                           \
  46     do {                                                                \
  47         t *_item = (item);                                              \
  48         pa_assert(_item);                                               \
  49         _item->prev = _item->next = NULL;                               \
  50     } while(0)
  51
  52 /* Prepend an item to the list */
  53 #define PA_LLIST_PREPEND(t,head,item)                                   \
  54     do {                                                                \
  55         t **_head = &(head), *_item = (item);                           \
  56         pa_assert(_item);                                               \
  57         if ((_item->next = *_head))                                     \
  58             _item->next->prev = _item;                                  \
  59         _item->prev = NULL;                                             \
  60         *_head = _item;                                                 \
  61     } while (0)
  62
  63 /* Remove an item from the list */
  64 #define PA_LLIST_REMOVE(t,head,item)                                    \
  65     do {                                                                \
  66         t **_head = &(head), *_item = (item);                           \
  67         pa_assert(_item);                                               \
  68         if (_item->next)                                                \
  69             _item->next->prev = _item->prev;                            \
  70         if (_item->prev)                                                \
  71             _item->prev->next = _item->next;                            \
  72         else {                                                          \
  73             pa_assert(*_head == _item);                                 \
  74             *_head = _item->next;                                       \
  75         }                                                               \
  76         _item->next = _item->prev = NULL;                               \
  77     } while(0)
  78
  79 /* Find the head of the list */
  80 #define PA_LLIST_FIND_HEAD(t,item,head)                                 \
  81     do {                                                                \
  82         t **_head = (head), *_item = (item);                            \
  83         *_head = _item;                                                 \
  84         pa_assert(_head);                                               \
  85         while ((*_head)->prev)                                          \
  86             *_head = (*_head)->prev;                                    \
  87     } while (0)
  88
  89 /* Insert an item after another one (a = where, b = what) */
  90 #define PA_LLIST_INSERT_AFTER(t,head,a,b)                               \
  91     do {                                                                \
  92         t **_head = &(head), *_a = (a), *_b = (b);                      \
  93         pa_assert(_b);                                                  \
  94         if (!_a) {                                                      \
  95             if ((_b->next = *_head))                                    \
  96                 _b->next->prev = _b;                                    \
  97             _b->prev = NULL;                                            \
  98             *_head = _b;                                                \
  99         } else {                                                        \
 100             if ((_b->next = _a->next))                                  \
 101                 _b->next->prev = _b;                                    \
 102             _b->prev = _a;                                              \
 103             _a->next = _b;                                              \
 104         }                                                               \
 105     } while (0)
 106
 107 #endif