Save a needless comparison when removing/adjusting timeouts

1 files changed, 17 insertions, 7 deletions

diff --git a/minheap-internal.h b/minheap-internal.h
index 39e3946a..53b88886 100644
--- a/minheap-internal.h
+++ b/minheap-internal.h
@@ -46,7 +46,6 @@ static inline void	     min_heap_ctor(min_heap_t* s);
 static inline void	     min_heap_dtor(min_heap_t* s);
 static inline void	     min_heap_elem_init(struct event* e);
 static inline int	     min_heap_elt_is_top(const struct event *e);
-static inline int	     min_heap_elem_greater(struct event *a, struct event *b);
 static inline int	     min_heap_empty(min_heap_t* s);
 static inline unsigned	     min_heap_size(min_heap_t* s);
 static inline struct event*  min_heap_top(min_heap_t* s);
@@ -56,12 +55,11 @@ static inline struct event*  min_heap_pop(min_heap_t* s);
 static inline int	     min_heap_adjust(min_heap_t *s, struct event* e);
 static inline int	     min_heap_erase(min_heap_t* s, struct event* e);
 static inline void	     min_heap_shift_up_(min_heap_t* s, unsigned hole_index, struct event* e);
+static inline void	     min_heap_shift_up_unconditional_(min_heap_t* s, unsigned hole_index, struct event* e);
 static inline void	     min_heap_shift_down_(min_heap_t* s, unsigned hole_index, struct event* e);
 
-int min_heap_elem_greater(struct event *a, struct event *b)
-{
-	return evutil_timercmp(&a->ev_timeout, &b->ev_timeout, >);
-}
+#define min_heap_elem_greater(a, b) \
+	(evutil_timercmp(&(a)->ev_timeout, &(b)->ev_timeout, >))
 
 void min_heap_ctor(min_heap_t* s) { s->p = 0; s->n = 0; s->a = 0; }
 void min_heap_dtor(min_heap_t* s) { if (s->p) mm_free(s->p); }
@@ -107,7 +105,7 @@ int min_heap_erase(min_heap_t* s, struct event* e)
 		   to be less than the parent, it can't need to shift both up and
 		   down. */
 		if (e->ev_timeout_pos.min_heap_idx > 0 && min_heap_elem_greater(s->p[parent], last))
-			min_heap_shift_up_(s, e->ev_timeout_pos.min_heap_idx, last);
+			min_heap_shift_up_unconditional_(s, e->ev_timeout_pos.min_heap_idx, last);
 		else
 			min_heap_shift_down_(s, e->ev_timeout_pos.min_heap_idx, last);
 		e->ev_timeout_pos.min_heap_idx = -1;
@@ -125,7 +123,7 @@ int min_heap_adjust(min_heap_t *s, struct event *e)
 		/* The position of e has changed; we shift it up or down
 		 * as needed.  We can't need to do both. */
 		if (e->ev_timeout_pos.min_heap_idx > 0 && min_heap_elem_greater(s->p[parent], e))
-			min_heap_shift_up_(s, e->ev_timeout_pos.min_heap_idx, e);
+			min_heap_shift_up_unconditional_(s, e->ev_timeout_pos.min_heap_idx, e);
 		else
 			min_heap_shift_down_(s, e->ev_timeout_pos.min_heap_idx, e);
 		return 0;
@@ -149,6 +147,18 @@ int min_heap_reserve(min_heap_t* s, unsigned n)
 	return 0;
 }
 
+void min_heap_shift_up_unconditional_(min_heap_t* s, unsigned hole_index, struct event* e)
+{
+    unsigned parent = (hole_index - 1) / 2;
+    do
+    {
+	(s->p[hole_index] = s->p[parent])->ev_timeout_pos.min_heap_idx = hole_index;
+	hole_index = parent;
+	parent = (hole_index - 1) / 2;
+    } while (hole_index && min_heap_elem_greater(s->p[parent], e));
+    (s->p[hole_index] = e)->ev_timeout_pos.min_heap_idx = hole_index;
+}
+
 void min_heap_shift_up_(min_heap_t* s, unsigned hole_index, struct event* e)
 {
     unsigned parent = (hole_index - 1) / 2;