src/shared/list.h

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 #ifndef foolisthfoo
   4 #define foolisthfoo
   5
   6 /***
   7   This file is part of systemd.
   8
   9   Copyright 2010 Lennart Poettering
  10
  11   systemd is free software; you can redistribute it and/or modify it
  12   under the terms of the GNU Lesser General Public License as published by
  13   the Free Software Foundation; either version 2.1 of the License, or
  14   (at your option) any later version.
  15
  16   systemd 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   Lesser General Public License for more details.
  20
  21   You should have received a copy of the GNU Lesser General Public License
  22   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  23 ***/
  24
  25 /* The head of the linked list. Use this in the structure that shall
  26  * contain the head of the linked list */
  27 #define LIST_HEAD(t,name)                                               \
  28         t *name
  29
  30 /* The pointers in the linked list's items. Use this in the item structure */
  31 #define LIST_FIELDS(t,name)                                             \
  32         t *name##_next, *name##_prev
  33
  34 /* Initialize the list's head */
  35 #define LIST_HEAD_INIT(t,head)                                          \
  36         do {                                                            \
  37                 (head) = NULL; }                                        \
  38         while(false)
  39
  40 /* Initialize a list item */
  41 #define LIST_INIT(t,name,item)                                          \
  42         do {                                                            \
  43                 t *_item = (item);                                      \
  44                 assert(_item);                                          \
  45                 _item->name##_prev = _item->name##_next = NULL;         \
  46         } while(false)
  47
  48 /* Prepend an item to the list */
  49 #define LIST_PREPEND(t,name,head,item)                                  \
  50         do {                                                            \
  51                 t **_head = &(head), *_item = (item);                   \
  52                 assert(_item);                                          \
  53                 if ((_item->name##_next = *_head))                      \
  54                         _item->name##_next->name##_prev = _item;        \
  55                 _item->name##_prev = NULL;                              \
  56                 *_head = _item;                                         \
  57         } while(false)
  58
  59 /* Remove an item from the list */
  60 #define LIST_REMOVE(t,name,head,item)                                   \
  61         do {                                                            \
  62                 t **_head = &(head), *_item = (item);                   \
  63                 assert(_item);                                          \
  64                 if (_item->name##_next)                                 \
  65                         _item->name##_next->name##_prev = _item->name##_prev; \
  66                 if (_item->name##_prev)                                 \
  67                         _item->name##_prev->name##_next = _item->name##_next; \
  68                 else {                                                  \
  69                         assert(*_head == _item);                        \
  70                         *_head = _item->name##_next;                    \
  71                 }                                                       \
  72                 _item->name##_next = _item->name##_prev = NULL;         \
  73         } while(false)
  74
  75 /* Find the head of the list */
  76 #define LIST_FIND_HEAD(t,name,item,head)                                \
  77         do {                                                            \
  78                 t *_item = (item);                                      \
  79                 assert(_item);                                          \
  80                 while (_item->name##_prev)                              \
  81                        _item = _item->name##_prev;                      \
  82                 (head) = _item;                                         \
  83         } while (false)
  84
  85 /* Find the head of the list */
  86 #define LIST_FIND_TAIL(t,name,item,tail)                                \
  87         do {                                                            \
  88                 t *_item = (item);                                      \
  89                 assert(_item);                                          \
  90                 while (_item->name##_next)                              \
  91                         _item = _item->name##_next;                     \
  92                 (tail) = _item;                                         \
  93         } while (false)
  94
  95 /* Insert an item after another one (a = where, b = what) */
  96 #define LIST_INSERT_AFTER(t,name,head,a,b)                              \
  97         do {                                                            \
  98                 t **_head = &(head), *_a = (a), *_b = (b);              \
  99                 assert(_b);                                             \
 100                 if (!_a) {                                              \
 101                         if ((_b->name##_next = *_head))                 \
 102                                 _b->name##_next->name##_prev = _b;      \
 103                         _b->name##_prev = NULL;                         \
 104                         *_head = _b;                                    \
 105                 } else {                                                \
 106                         if ((_b->name##_next = _a->name##_next))        \
 107                                 _b->name##_next->name##_prev = _b;      \
 108                         _b->name##_prev = _a;                           \
 109                         _a->name##_next = _b;                           \
 110                 }                                                       \
 111         } while(false)
 112
 113 #define LIST_JUST_US(name,item)                                         \
 114         (!(item)->name##_prev && !(item)->name##_next)                  \
 115
 116 #define LIST_FOREACH(name,i,head)                                       \
 117         for ((i) = (head); (i); (i) = (i)->name##_next)
 118
 119 #define LIST_FOREACH_SAFE(name,i,n,head)                                \
 120         for ((i) = (head); (i) && (((n) = (i)->name##_next), 1); (i) = (n))
 121
 122 #define LIST_FOREACH_BEFORE(name,i,p)                                   \
 123         for ((i) = (p)->name##_prev; (i); (i) = (i)->name##_prev)
 124
 125 #define LIST_FOREACH_AFTER(name,i,p)                                    \
 126         for ((i) = (p)->name##_next; (i); (i) = (i)->name##_next)
 127
 128 #endif