src/basic/list.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 /* The head of the linked list. Use this in the structure that shall
   5  * contain the head of the linked list */
   6 #define LIST_HEAD(t,name)                                               \
   7         t *name
   8
   9 /* The pointers in the linked list's items. Use this in the item structure */
  10 #define LIST_FIELDS(t,name)                                             \
  11         t *name##_next, *name##_prev
  12
  13 /* Initialize the list's head */
  14 #define LIST_HEAD_INIT(head)                                            \
  15         do {                                                            \
  16                 (head) = NULL; }                                        \
  17         while (false)
  18
  19 /* Initialize a list item */
  20 #define LIST_INIT(name,item)                                            \
  21         do {                                                            \
  22                 typeof(*(item)) *_item = (item);                        \
  23                 assert(_item);                                          \
  24                 _item->name##_prev = _item->name##_next = NULL;         \
  25         } while (false)
  26
  27 /* Prepend an item to the list */
  28 #define LIST_PREPEND(name,head,item)                                    \
  29         do {                                                            \
  30                 typeof(*(head)) **_head = &(head), *_item = (item);     \
  31                 assert(_item);                                          \
  32                 if ((_item->name##_next = *_head))                      \
  33                         _item->name##_next->name##_prev = _item;        \
  34                 _item->name##_prev = NULL;                              \
  35                 *_head = _item;                                         \
  36         } while (false)
  37
  38 /* Append an item to the list */
  39 #define LIST_APPEND(name,head,item)                                     \
  40         do {                                                            \
  41                 typeof(*(head)) *_tail;                                 \
  42                 LIST_FIND_TAIL(name,head,_tail);                        \
  43                 LIST_INSERT_AFTER(name,head,_tail,item);                \
  44         } while (false)
  45
  46 /* Remove an item from the list */
  47 #define LIST_REMOVE(name,head,item)                                     \
  48         do {                                                            \
  49                 typeof(*(head)) **_head = &(head), *_item = (item);     \
  50                 assert(_item);                                          \
  51                 if (_item->name##_next)                                 \
  52                         _item->name##_next->name##_prev = _item->name##_prev; \
  53                 if (_item->name##_prev)                                 \
  54                         _item->name##_prev->name##_next = _item->name##_next; \
  55                 else {                                                  \
  56                         assert(*_head == _item);                        \
  57                         *_head = _item->name##_next;                    \
  58                 }                                                       \
  59                 _item->name##_next = _item->name##_prev = NULL;         \
  60         } while (false)
  61
  62 /* Find the head of the list */
  63 #define LIST_FIND_HEAD(name,item,head)                                  \
  64         do {                                                            \
  65                 typeof(*(item)) *_item = (item);                        \
  66                 if (!_item)                                             \
  67                         (head) = NULL;                                  \
  68                 else {                                                  \
  69                         while (_item->name##_prev)                      \
  70                                 _item = _item->name##_prev;             \
  71                         (head) = _item;                                 \
  72                 }                                                       \
  73         } while (false)
  74
  75 /* Find the tail of the list */
  76 #define LIST_FIND_TAIL(name,item,tail)                                  \
  77         do {                                                            \
  78                 typeof(*(item)) *_item = (item);                        \
  79                 if (!_item)                                             \
  80                         (tail) = NULL;                                  \
  81                 else {                                                  \
  82                         while (_item->name##_next)                      \
  83                                 _item = _item->name##_next;             \
  84                         (tail) = _item;                                 \
  85                 }                                                       \
  86         } while (false)
  87
  88 /* Insert an item after another one (a = where, b = what) */
  89 #define LIST_INSERT_AFTER(name,head,a,b)                                \
  90         do {                                                            \
  91                 typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
  92                 assert(_b);                                             \
  93                 if (!_a) {                                              \
  94                         if ((_b->name##_next = *_head))                 \
  95                                 _b->name##_next->name##_prev = _b;      \
  96                         _b->name##_prev = NULL;                         \
  97                         *_head = _b;                                    \
  98                 } else {                                                \
  99                         if ((_b->name##_next = _a->name##_next))        \
 100                                 _b->name##_next->name##_prev = _b;      \
 101                         _b->name##_prev = _a;                           \
 102                         _a->name##_next = _b;                           \
 103                 }                                                       \
 104         } while (false)
 105
 106 /* Insert an item before another one (a = where, b = what) */
 107 #define LIST_INSERT_BEFORE(name,head,a,b)                               \
 108         do {                                                            \
 109                 typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
 110                 assert(_b);                                             \
 111                 if (!_a) {                                              \
 112                         if (!*_head) {                                  \
 113                                 _b->name##_next = NULL;                 \
 114                                 _b->name##_prev = NULL;                 \
 115                                 *_head = _b;                            \
 116                         } else {                                        \
 117                                 typeof(*(head)) *_tail = (head);        \
 118                                 while (_tail->name##_next)              \
 119                                         _tail = _tail->name##_next;     \
 120                                 _b->name##_next = NULL;                 \
 121                                 _b->name##_prev = _tail;                \
 122                                 _tail->name##_next = _b;                \
 123                         }                                               \
 124                 } else {                                                \
 125                         if ((_b->name##_prev = _a->name##_prev))        \
 126                                 _b->name##_prev->name##_next = _b;      \
 127                         else                                            \
 128                                 *_head = _b;                            \
 129                         _b->name##_next = _a;                           \
 130                         _a->name##_prev = _b;                           \
 131                 }                                                       \
 132         } while (false)
 133
 134 #define LIST_JUST_US(name,item)                                         \
 135         (!(item)->name##_prev && !(item)->name##_next)                  \
 136
 137 #define LIST_FOREACH(name,i,head)                                       \
 138         for ((i) = (head); (i); (i) = (i)->name##_next)
 139
 140 #define LIST_FOREACH_SAFE(name,i,n,head)                                \
 141         for ((i) = (head); (i) && (((n) = (i)->name##_next), 1); (i) = (n))
 142
 143 #define LIST_FOREACH_BEFORE(name,i,p)                                   \
 144         for ((i) = (p)->name##_prev; (i); (i) = (i)->name##_prev)
 145
 146 #define LIST_FOREACH_AFTER(name,i,p)                                    \
 147         for ((i) = (p)->name##_next; (i); (i) = (i)->name##_next)
 148
 149 /* Iterate through all the members of the list p is included in, but skip over p */
 150 #define LIST_FOREACH_OTHERS(name,i,p)                                   \
 151         for (({                                                         \
 152                 (i) = (p);                                              \
 153                 while ((i) && (i)->name##_prev)                         \
 154                         (i) = (i)->name##_prev;                         \
 155                 if ((i) == (p))                                         \
 156                         (i) = (p)->name##_next;                         \
 157              });                                                        \
 158              (i);                                                       \
 159              (i) = (i)->name##_next == (p) ? (p)->name##_next : (i)->name##_next)
 160
 161 /* Loop starting from p->next until p->prev.
 162    p can be adjusted meanwhile. */
 163 #define LIST_LOOP_BUT_ONE(name,i,head,p)                                \
 164         for ((i) = (p)->name##_next ? (p)->name##_next : (head);        \
 165              (i) != (p);                                                \
 166              (i) = (i)->name##_next ? (i)->name##_next : (head))
 167
 168 #define LIST_IS_EMPTY(head)                                             \
 169         (!(head))