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,name)                                             \
  13         t *name##_next, *name##_prev
  14
  15 /* Initialize the list's head */
  16 #define LIST_HEAD_INIT(t,head)                                          \
  17         do {                                                            \
  18                 (head) = NULL; }                                        \
  19         while(false)
  20
  21 /* Initialize a list item */
  22 #define LIST_INIT(t,name,item)                                          \
  23         do {                                                            \
  24                 t *_item = (item);                                      \
  25                 assert(_item);                                          \
  26                 _item->name##_prev = _item->name##_next = NULL;         \
  27         } while(false)
  28
  29 /* Prepend an item to the list */
  30 #define LIST_PREPEND(t,name,head,item)                                  \
  31         do {                                                            \
  32                 t **_head = &(head), *_item = (item);                   \
  33                 assert(_item);                                          \
  34                 if ((_item->name##_next = *_head))                      \
  35                         _item->name##_next->name##_prev = _item;        \
  36                 _item->name##_prev = NULL;                              \
  37                 *_head = _item;                                         \
  38         } while(false)
  39
  40 /* Remove an item from the list */
  41 #define LIST_REMOVE(t,name,head,item)                                   \
  42         do {                                                            \
  43                 t **_head = &(head), *_item = (item);                   \
  44                 assert(_item);                                          \
  45                 if (_item->name##_next)                                 \
  46                         _item->name##_next->name##_prev = _item->name##_prev; \
  47                 if (_item->name##_prev)                                 \
  48                         _item->name##_prev->name##_next = _item->name##_next; \
  49                 else {                                                  \
  50                         assert(*_head == _item);                        \
  51                         *_head = _item->name##_next;                    \
  52                 }                                                       \
  53                 _item->name##_next = _item->name##_prev = NULL;         \
  54         } while(false)
  55
  56 /* Find the head of the list */
  57 #define LIST_FIND_HEAD(t,name,item,head)                                \
  58         do {                                                            \
  59                 t *_item = (item);                                      \
  60                 assert(_item);                                          \
  61                 while ((_item->name##_prev)                             \
  62                        _item = _item->name##_prev;                      \
  63                 (head) = _item;                                         \
  64         } while (false)
  65
  66 /* Find the head of the list */
  67 #define LIST_FIND_TAIL(t,name,item,tail)                                \
  68         do {                                                            \
  69                 t *_item = (item);                                      \
  70                 assert(_item);                                          \
  71                 while (_item->name##_next)                              \
  72                         _item = _item->name##_next;                     \
  73                 (tail) = _item;                                         \
  74         } while (false)
  75
  76 /* Insert an item after another one (a = where, b = what) */
  77 #define LIST_INSERT_AFTER(t,name,head,a,b)                              \
  78         do {                                                            \
  79                 t **_head = &(head), *_a = (a), *_b = (b);              \
  80                 assert(_b);                                             \
  81                 if (!_a) {                                              \
  82                         if ((_b->name##_next = *_head))                 \
  83                                 _b->name##_next->name##_prev = _b;      \
  84                         _b->name##_prev = NULL;                         \
  85                         *_head = _b;                                    \
  86                 } else {                                                \
  87                         if ((_b->name##_next = _a->name##_next))        \
  88                                 _b->name##_next->name##_prev = _b;      \
  89                         _b->name##_prev = _a;                           \
  90                         _a->name##_next = _b;                           \
  91                 }                                                       \
  92         } while(false)
  93
  94 #define LIST_FOREACH(name,i,head)                                       \
  95         for ((i) = (head); (i); (i) = (i)->name##_next)
  96
  97 #define LIST_FOREACH_SAFE(name,i,n,head)                                \
  98         for ((i) = (head); (i) && (((n) = (i)->name##_next), 1); (i) = (n))
  99
 100 #endif