Add a reverse () call to hb_array_t.

src/hb-array.hh

@@ -171,6 +171,21 @@ struct hb_array_t : hb_iter_with_fallback_t<hb_array_t<Type>, Type&>
 
   unsigned int get_size () const { return length * this->get_item_size (); }
 
+  void reverse ()
+  {
+    int rhs = length - 1;
+    int lhs = 0;
+    while (rhs > lhs)
+    {
+      Type value_rhs = arrayZ[rhs];
+      Type value_lhs = arrayZ[lhs];
+      arrayZ[rhs] = value_lhs;
+      arrayZ[lhs] = value_rhs;
+      rhs--;
+      lhs++;
+    }
+  }
+
   hb_array_t sub_array (unsigned int start_offset = 0, unsigned int *seg_count = nullptr /* IN/OUT */) const
   {
     if (!start_offset && !seg_count)

src/hb-ot-cmap-table.hh

@@ -850,6 +850,20 @@ struct VariationSelectorRecord
     return GLYPH_VARIANT_NOT_FOUND;
   }
 
+  VariationSelectorRecord(const VariationSelectorRecord& other)
+  {
+    *this = other;
+  }
+
+  void operator= (const VariationSelectorRecord& other)
+  {
+    varSelector = other.varSelector;
+    HBUINT32 offset = other.defaultUVS;
+    defaultUVS = offset;
+    offset = other.nonDefaultUVS;
+    nonDefaultUVS = offset;
+  }
+
   void collect_unicodes (hb_set_t *out, const void *base) const
   {
     (base+defaultUVS).collect_unicodes (out);
@@ -992,17 +1006,7 @@ struct CmapSubtableFormat14
 
   void _reverse_variation_records ()
   {
-    int rhs = record.len - 1;
+    record.as_array ().reverse ();
-    int lhs = 0;
-    while (rhs > lhs)
-    {
-      int value_rhs = record[rhs].varSelector;
-      int value_lhs = record[lhs].varSelector;
-      record[rhs].varSelector = value_lhs;
-      record[lhs].varSelector = value_rhs;
-      rhs--;
-      lhs++;
-    }
   }
 
   void _add_links_to_variation_records (hb_serialize_context_t *c,