src/basic/list.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include "macro.h"
   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(head)                                            \
  17         do {                                                            \
  18                 (head) = NULL;                                          \
  19         } while (false)
  20
  21 /* Initialize a list item */
  22 #define LIST_INIT(name,item)                                            \
  23         do {                                                            \
  24                 typeof(*(item)) *_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(name,head,item)                                    \
  31         do {                                                            \
  32                 typeof(*(head)) **_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 /* Append an item to the list */
  41 #define LIST_APPEND(name,head,item)                                     \
  42         do {                                                            \
  43                 typeof(*(head)) **_hhead = &(head), *_tail;             \
  44                 LIST_FIND_TAIL(name, *_hhead, _tail);                   \
  45                 LIST_INSERT_AFTER(name, *_hhead, _tail, item);          \
  46         } while (false)
  47
  48 /* Remove an item from the list */
  49 #define LIST_REMOVE(name,head,item)                                     \
  50         do {                                                            \
  51                 typeof(*(head)) **_head = &(head), *_item = (item);     \
  52                 assert(_item);                                          \
  53                 if (_item->name##_next)                                 \
  54                         _item->name##_next->name##_prev = _item->name##_prev; \
  55                 if (_item->name##_prev)                                 \
  56                         _item->name##_prev->name##_next = _item->name##_next; \
  57                 else {                                                  \
  58                         assert(*_head == _item);                        \
  59                         *_head = _item->name##_next;                    \
  60                 }                                                       \
  61                 _item->name##_next = _item->name##_prev = NULL;         \
  62         } while (false)
  63
  64 /* Find the head of the list */
  65 #define LIST_FIND_HEAD(name,item,head)                                  \
  66         do {                                                            \
  67                 typeof(*(item)) *_item = (item);                        \
  68                 if (!_item)                                             \
  69                         (head) = NULL;                                  \
  70                 else {                                                  \
  71                         while (_item->name##_prev)                      \
  72                                 _item = _item->name##_prev;             \
  73                         (head) = _item;                                 \
  74                 }                                                       \
  75         } while (false)
  76
  77 /* Find the tail of the list */
  78 #define LIST_FIND_TAIL(name,item,tail)                                  \
  79         do {                                                            \
  80                 typeof(*(item)) *_item = (item);                        \
  81                 if (!_item)                                             \
  82                         (tail) = NULL;                                  \
  83                 else {                                                  \
  84                         while (_item->name##_next)                      \
  85                                 _item = _item->name##_next;             \
  86                         (tail) = _item;                                 \
  87                 }                                                       \
  88         } while (false)
  89
  90 /* Insert an item after another one (a = where, b = what) */
  91 #define LIST_INSERT_AFTER(name,head,a,b)                                \
  92         do {                                                            \
  93                 typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
  94                 assert(_b);                                             \
  95                 if (!_a) {                                              \
  96                         if ((_b->name##_next = *_head))                 \
  97                                 _b->name##_next->name##_prev = _b;      \
  98                         _b->name##_prev = NULL;                         \
  99                         *_head = _b;                                    \
 100                 } else {                                                \
 101                         if ((_b->name##_next = _a->name##_next))        \
 102                                 _b->name##_next->name##_prev = _b;      \
 103                         _b->name##_prev = _a;                           \
 104                         _a->name##_next = _b;                           \
 105                 }                                                       \
 106         } while (false)
 107
 108 /* Insert an item before another one (a = where, b = what) */
 109 #define LIST_INSERT_BEFORE(name,head,a,b)                               \
 110         do {                                                            \
 111                 typeof(*(head)) **_head = &(head), *_a = (a), *_b = (b); \
 112                 assert(_b);                                             \
 113                 if (!_a) {                                              \
 114                         if (!*_head) {                                  \
 115                                 _b->name##_next = NULL;                 \
 116                                 _b->name##_prev = NULL;                 \
 117                                 *_head = _b;                            \
 118                         } else {                                        \
 119                                 typeof(*(head)) *_tail = (head);        \
 120                                 while (_tail->name##_next)              \
 121                                         _tail = _tail->name##_next;     \
 122                                 _b->name##_next = NULL;                 \
 123                                 _b->name##_prev = _tail;                \
 124                                 _tail->name##_next = _b;                \
 125                         }                                               \
 126                 } else {                                                \
 127                         if ((_b->name##_prev = _a->name##_prev))        \
 128                                 _b->name##_prev->name##_next = _b;      \
 129                         else                                            \
 130                                 *_head = _b;                            \
 131                         _b->name##_next = _a;                           \
 132                         _a->name##_prev = _b;                           \
 133                 }                                                       \
 134         } while (false)
 135
 136 #define LIST_JUST_US(name,item)                                         \
 137         (!(item)->name##_prev && !(item)->name##_next)                  \
 138
 139 #define LIST_FOREACH(name,i,head)                                       \
 140         for ((i) = (head); (i); (i) = (i)->name##_next)
 141
 142 #define LIST_FOREACH_SAFE(name,i,n,head)                                \
 143         for ((i) = (head); (i) && (((n) = (i)->name##_next), 1); (i) = (n))
 144
 145 #define LIST_FOREACH_BEFORE(name,i,p)                                   \
 146         for ((i) = (p)->name##_prev; (i); (i) = (i)->name##_prev)
 147
 148 #define LIST_FOREACH_AFTER(name,i,p)                                    \
 149         for ((i) = (p)->name##_next; (i); (i) = (i)->name##_next)
 150
 151 /* Iterate through all the members of the list p is included in, but skip over p */
 152 #define LIST_FOREACH_OTHERS(name,i,p)                                   \
 153         for (({                                                         \
 154                 (i) = (p);                                              \
 155                 while ((i) && (i)->name##_prev)                         \
 156                         (i) = (i)->name##_prev;                         \
 157                 if ((i) == (p))                                         \
 158                         (i) = (p)->name##_next;                         \
 159              });                                                        \
 160              (i);                                                       \
 161              (i) = (i)->name##_next == (p) ? (p)->name##_next : (i)->name##_next)
 162
 163 /* Loop starting from p->next until p->prev.
 164    p can be adjusted meanwhile. */
 165 #define LIST_LOOP_BUT_ONE(name,i,head,p)                                \
 166         for ((i) = (p)->name##_next ? (p)->name##_next : (head);        \
 167              (i) != (p);                                                \
 168              (i) = (i)->name##_next ? (i)->name##_next : (head))
 169
 170 #define LIST_IS_EMPTY(head)                                             \
 171         (!(head))