tail call

source/list.h

@@ -28,6 +28,10 @@
 #include <stddef.h>
 #endif
 
+#ifndef NDEBUG
+#include <assert.h>
+#endif
+
 struct list_head {
     struct list_head *prev;
     struct list_head *next;
@@ -82,6 +86,29 @@ static inline int list_empty(struct list_head *el)
     return el->next == el;
 }
 
+/* Move all elements from 'src' to 'dst', leaving 'src' empty.
+   'dst' must be empty before this call. */
+static inline void list_splice(struct list_head *dst, struct list_head *src)
+{
+#ifndef NDEBUG
+    assert(dst != src);
+    assert(list_empty(dst));
+#endif
+    if (!list_empty(src)) {
+        struct list_head *first = src->next;
+        struct list_head *last = src->prev;
+
+        /* Link dst to src's elements */
+        dst->next = first;
+        dst->prev = last;
+        first->prev = dst;
+        last->next = dst;
+
+        /* Reinitialize src as empty */
+        init_list_head(src);
+    }
+}
+
 #define list_for_each(el, head) \
   for(el = (head)->next; el != (head); el = el->next)