#include <stdbool.h>
#include <stddef.h>
#include <assert.h>
+#include "c99_compat.h"
struct list_head
list->prev = item;
}
+static inline bool list_empty(const struct list_head *list);
+
static inline void list_replace(struct list_head *from, struct list_head *to)
{
- to->prev = from->prev;
- to->next = from->next;
- from->next->prev = to;
- from->prev->next = to;
+ if (list_empty(from)) {
+ list_inithead(to);
+ } else {
+ to->prev = from->prev;
+ to->next = from->next;
+ from->next->prev = to;
+ from->prev->next = to;
+ }
}
static inline void list_del(struct list_head *item)
item->prev = item;
}
-static inline bool list_empty(struct list_head *list)
+static inline bool list_empty(const struct list_head *list)
{
return list->next == list;
}
-static inline unsigned list_length(struct list_head *list)
+/**
+ * Returns whether the list has exactly one element.
+ */
+static inline bool list_is_singular(const struct list_head *list)
+{
+ return list->next != NULL && list->next != list && list->next->next == list;
+}
+
+static inline unsigned list_length(const struct list_head *list)
{
struct list_head *node;
unsigned length = 0;
dst->prev = src->prev;
}
-static inline void list_validate(struct list_head *list)
+static inline void list_validate(const struct list_head *list)
{
struct list_head *node;
assert(list->next->prev == list && list->prev->next == list);