commit f15858be5f09a9fdfbec9ccc68490e23e5db35ad
author Behdad Esfahbod <behdad@behdad.org> Mon Nov 01 20:26:07 2021 -0600
committer Behdad Esfahbod <behdad@behdad.org> Mon Nov 01 20:26:07 2021 -0600
tree e390e1dcc23709d06abf7d2ae667602761a4d433
parent 11135150a7e9955aefbf9ac943367a618b513981

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

src/hb-vector.hh

diff --git a/src/hb-vector.hh b/src/hb-vector.hh
index 92c74dc..acd66a7 100644
--- a/src/hb-vector.hh
+++ b/src/hb-vector.hh
@@ -51,6 +51,8 @@
 	    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 ()