list.h

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 #ifndef foolisthfoo
   4 #define foolisthfoo
   5
   6 /* The head of the linked list. Use this in the structure that shall
   7  * contain the head of the linked list */
   8 #define LIST_HEAD(t,name)                                               \
   9     t *name
  10
  11 /* The pointers in the linked list's items. Use this in the item structure */
  12 #define LIST_FIELDS(t)                                                  \
  13     t *next, *prev
  14
  15 /* Initialize the list's head */
  16 #define LIST_HEAD_INIT(t,item)                                          \
  17         do {                                                            \
  18                 (item) = (t*) NULL; }                                   \
  19         while(false)
  20
  21 /* Initialize a list item */
  22 #define LIST_INIT(t,item)                                               \
  23         do {                                                            \
  24                 t *_item = (item);                                      \
  25                 assert(_item);                                          \
  26                 _item->prev = _item->next = NULL;                       \
  27         } while(false)
  28
  29 /* Prepend an item to the list */
  30 #define LIST_PREPEND(t,head,item)                                       \
  31         do {                                                            \
  32                 t **_head = &(head), *_item = (item);                   \
  33                 assert(_item);                                          \
  34                 if ((_item->next = *_head))                             \
  35                         _item->next->prev = _item;                      \
  36                 _item->prev = NULL;                                     \
  37                 *_head = _item;                                         \
  38         } while(false)
  39
  40 /* Remove an item from the list */
  41 #define LIST_REMOVE(t,head,item)                                        \
  42         do {                                                            \
  43                 t **_head = &(head), *_item = (item);                   \
  44                 assert(_item);                                          \
  45                 if (_item->next)                                        \
  46                         _item->next->prev = _item->prev;                \
  47                 if (_item->prev)                                        \
  48                         _item->prev->next = _item->next;                \
  49                 else {                                                  \
  50                         assert(*_head == _item);                        \
  51                         *_head = _item->next;                           \
  52                 }                                                       \
  53                 _item->next = _item->prev = NULL;                       \
  54         } while(false)
  55
  56 /* Find the head of the list */
  57 #define LIST_FIND_HEAD(t,item,head)                                     \
  58         do {                                                            \
  59                 t **_head = (head), *_item = (item);                    \
  60                 *_head = _item;                                         \
  61                 assert(_head);                                          \
  62                 while ((*_head)->prev)                                  \
  63                         *_head = (*_head)->prev;                        \
  64         } while (false)
  65
  66 /* Insert an item after another one (a = where, b = what) */
  67 #define LIST_INSERT_AFTER(t,head,a,b)                                   \
  68         do {                                                            \
  69                 t **_head = &(head), *_a = (a), *_b = (b);              \
  70                 assert(_b);                                             \
  71                 if (!_a) {                                              \
  72                         if ((_b->next = *_head))                        \
  73                                 _b->next->prev = _b;                    \
  74                         _b->prev = NULL;                                \
  75                         *_head = _b;                                    \
  76                 } else {                                                \
  77                         if ((_b->next = _a->next))                      \
  78                                 _b->next->prev = _b;                    \
  79                         _b->prev = _a;                                  \
  80                         _a->next = _b;                                  \
  81                 }                                                       \
  82         } while(false)
  83
  84 #define LIST_FOREACH(i,head)                                            \
  85         for (i = (head); i; i = i->next)
  86
  87 #define LIST_FOREACH_SAFE(i,n,head)                                     \
  88         for (i = (head); i && ((n = i->next), 1); i = n)
  89
  90 #endif