[vector] Pre-allocate if iterator has random-access length

2021-11-01 20:26:07 -06:00 · 2021-11-01 20:26:07 -06:00 · f15858be5f
parent 11135150a7
commit f15858be5f
1 changed files with 2 additions and 0 deletions
--- a/src/hb-vector.hh
+++ b/src/hb-vector.hh
@ -51,6 +51,8 @@ struct hb_vector_t
 	    hb_requires (hb_is_iterable (Iterable))>
  hb_vector_t (const Iterable &o) : hb_vector_t ()
  {
+    if (hb_iter (o).is_random_access_iterator)
+      alloc (hb_len (hb_iter (o)));
    hb_copy (o, *this);
  }
  hb_vector_t (const hb_vector_t &o) : hb_vector_t ()