4 #include <ccan/container_of/container_of.h>
7 * struct list_node - an entry in a doubly-linked list
8 * @next: next entry (self if empty)
9 * @prev: previous entry (self if empty)
11 * This is used as an entry in a linked list.
15 * // Linked list of all us children.
16 * struct list_node list;
21 struct list_node *next, *prev;
25 * struct list_head - the head of a doubly-linked list
26 * @h: the list_head (containing next and prev pointers)
28 * This is used as the head of a linked list.
32 * struct list_head children;
33 * unsigned int num_children;
42 * list_check - check a list for consistency
44 * @abortstr: the location to print on aborting, or NULL.
46 * Because list_nodes have redundant information, consistency checking between
47 * the back and forward links can be done. This is useful as a debugging check.
48 * If @abortstr is non-NULL, that will be printed in a diagnostic if the list
49 * is inconsistent, and the function will abort.
51 * Returns the list head if the list is consistent, NULL if not (it
52 * can never return NULL if @abortstr is set).
55 * static void dump_parent(struct parent *p)
59 * printf("%s (%u children):\n", p->name, p->num_children);
60 * list_check(&p->children, "bad child list");
61 * list_for_each(&p->children, c, list)
62 * printf(" -> %s\n", c->name);
65 struct list_head *list_check(const struct list_head *h, const char *abortstr);
67 #ifdef CCAN_LIST_DEBUG
68 #define debug_list(h) list_check((h), __func__)
70 #define debug_list(h) (h)
74 * LIST_HEAD - define and initalize an empty list_head
75 * @name: the name of the list.
77 * The LIST_HEAD macro defines a list_head and initializes it to an empty
78 * list. It can be prepended by "static" to define a static list_head.
81 * static LIST_HEAD(my_global_list);
83 #define LIST_HEAD(name) \
84 struct list_head name = { { &name.n, &name.n } }
87 * list_head_init - initialize a list_head
88 * @h: the list_head to set to the empty list
92 * struct parent *parent = malloc(sizeof(*parent));
94 * list_head_init(&parent->children);
95 * parent->num_children = 0;
97 static inline void list_head_init(struct list_head *h)
99 h->n.next = h->n.prev = &h->n;
103 * list_add - add an entry at the start of a linked list.
104 * @h: the list_head to add the node to
105 * @n: the list_node to add to the list.
107 * The list_node does not need to be initialized; it will be overwritten.
109 * struct child *child = malloc(sizeof(*child));
111 * child->name = "marvin";
112 * list_add(&parent->children, &child->list);
113 * parent->num_children++;
115 static inline void list_add(struct list_head *h, struct list_node *n)
125 * list_add_tail - add an entry at the end of a linked list.
126 * @h: the list_head to add the node to
127 * @n: the list_node to add to the list.
129 * The list_node does not need to be initialized; it will be overwritten.
131 * list_add_tail(&parent->children, &child->list);
132 * parent->num_children++;
134 static inline void list_add_tail(struct list_head *h, struct list_node *n)
144 * list_del - delete an entry from a linked list.
145 * @n: the list_node to delete from the list.
148 * list_del(&child->list);
149 * parent->num_children--;
151 static inline void list_del(struct list_node *n)
153 n->next->prev = n->prev;
154 n->prev->next = n->next;
155 (void)debug_list(n->next);
156 #ifdef CCAN_LIST_DEBUG
157 /* Catch use-after-del. */
158 n->next = n->prev = NULL;
163 * list_empty - is a list empty?
166 * If the list is empty, returns true.
169 * assert(list_empty(&parent->children) == (parent->num_children == 0));
171 static inline bool list_empty(const struct list_head *h)
174 return h->n.next == &h->n;
178 * list_entry - convert a list_node back into the structure containing it.
180 * @type: the type of the entry
181 * @member: the list_node member of the type
184 * // First list entry is children.next; convert back to child.
185 * child = list_entry(parent->children.n.next, struct child, list);
188 * list_top(), list_for_each()
190 #define list_entry(n, type, member) container_of(n, type, member)
193 * list_top - get the first entry in a list
195 * @type: the type of the entry
196 * @member: the list_node member of the type
198 * If the list is empty, returns NULL.
201 * struct child *first;
202 * first = list_top(&parent->children, struct child, list);
204 #define list_top(h, type, member) \
205 (list_empty(h) ? NULL : list_entry((h)->n.next, type, member))
208 * list_tail - get the last entry in a list
210 * @type: the type of the entry
211 * @member: the list_node member of the type
213 * If the list is empty, returns NULL.
216 * struct child *last;
217 * last = list_tail(&parent->children, struct child, list);
219 #define list_tail(h, type, member) \
220 (list_empty(h) ? NULL : list_entry((h)->n.prev, type, member))
223 * list_for_each - iterate through a list.
225 * @i: the structure containing the list_node
226 * @member: the list_node member of the structure
228 * This is a convenient wrapper to iterate @i over the entire list. It's
229 * a for loop, so you can break and continue as normal.
232 * list_for_each(&parent->children, child, list)
233 * printf("Name: %s\n", child->name);
235 #define list_for_each(h, i, member) \
236 for (i = container_of_var(debug_list(h)->n.next, i, member); \
237 &i->member != &(h)->n; \
238 i = container_of_var(i->member.next, i, member))
241 * list_for_each_safe - iterate through a list, maybe during deletion
243 * @i: the structure containing the list_node
244 * @nxt: the structure containing the list_node
245 * @member: the list_node member of the structure
247 * This is a convenient wrapper to iterate @i over the entire list. It's
248 * a for loop, so you can break and continue as normal. The extra variable
249 * @nxt is used to hold the next element, so you can delete @i from the list.
252 * struct child *next;
253 * list_for_each_safe(&parent->children, child, next, list) {
254 * list_del(&child->list);
255 * parent->num_children--;
258 #define list_for_each_safe(h, i, nxt, member) \
259 for (i = container_of_var(debug_list(h)->n.next, i, member), \
260 nxt = container_of_var(i->member.next, i, member); \
261 &i->member != &(h)->n; \
262 i = nxt, nxt = container_of_var(i->member.next, i, member))
263 #endif /* CCAN_LIST_H */