#include <stdbool.h>
#include <assert.h>
#include <ccan/container_of/container_of.h>
+#include <ccan/check_type/check_type.h>
/**
* struct list_node - an entry in a doubly-linked list
* struct child *first;
* first = list_top(&parent->children, struct child, list);
*/
-#define list_top(h, type, member) \
- (list_empty(h) ? NULL : list_entry((h)->n.next, type, member))
+#define list_top(h, type, member) \
+ ((type *)list_top_((h), list_off_(type, member)))
+
+static inline const void *list_top_(const struct list_head *h, size_t off)
+{
+ if (list_empty(h))
+ return NULL;
+ return (const char *)h->n.next - off;
+}
/**
* list_tail - get the last entry in a list
* last = list_tail(&parent->children, struct child, list);
*/
#define list_tail(h, type, member) \
- (list_empty(h) ? NULL : list_entry((h)->n.prev, type, member))
+ ((type *)list_tail_((h), list_off_(type, member)))
+
+static inline const void *list_tail_(const struct list_head *h, size_t off)
+{
+ if (list_empty(h))
+ return NULL;
+ return (const char *)h->n.prev - off;
+}
/**
* list_for_each - iterate through a list.
- * @h: the list_head
+ * @h: the list_head (warning: evaluated multiple times!)
* @i: the structure containing the list_node
* @member: the list_node member of the structure
*
&i->member != &(h)->n; \
i = container_of_var(i->member.next, i, member))
+/**
+ * list_for_each_rev - iterate through a list backwards.
+ * @h: the list_head
+ * @i: the structure containing the list_node
+ * @member: the list_node member of the structure
+ *
+ * This is a convenient wrapper to iterate @i over the entire list. It's
+ * a for loop, so you can break and continue as normal.
+ *
+ * Example:
+ * list_for_each_rev(&parent->children, child, list)
+ * printf("Name: %s\n", child->name);
+ */
+#define list_for_each_rev(h, i, member) \
+ for (i = container_of_var(list_debug(h)->n.prev, i, member); \
+ &i->member != &(h)->n; \
+ i = container_of_var(i->member.prev, i, member))
+
/**
* list_for_each_safe - iterate through a list, maybe during deletion
* @h: the list_head
nxt = container_of_var(i->member.next, i, member); \
&i->member != &(h)->n; \
i = nxt, nxt = container_of_var(i->member.next, i, member))
+
+/* Get the offset of the member, but make sure it's a list_node. */
+#define list_off_(type, member) \
+ (container_off(type, member) + \
+ check_type(((type *)0)->member, struct list_node))
+
#endif /* CCAN_LIST_H */