From 0a1b26b862467d318596d03b9300ae350be5c99e Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Mon, 24 Feb 2025 20:07:59 -0700
Subject: [PATCH] [coord-setter] Reduce malloc pressure

~15% speedup benchmark-font draw of varc-hanzi.ttf
---
 src/OT/Var/VARC/coord-setter.hh | 38 +++++++++++++++++++++++++++------
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/src/OT/Var/VARC/coord-setter.hh b/src/OT/Var/VARC/coord-setter.hh
index a2b483ce2..47685290c 100644
--- a/src/OT/Var/VARC/coord-setter.hh
+++ b/src/OT/Var/VARC/coord-setter.hh
@@ -11,22 +11,46 @@ namespace OT {
 
 struct coord_setter_t
 {
-  coord_setter_t (hb_array_t<const int> coords) :
-    coords (coords) {}
+  coord_setter_t (hb_array_t<const int> coords_)
+  {
+    length = coords_.length;
+    if (length <= ARRAY_LENGTH (static_coords))
+      hb_memcpy (static_coords, coords_.arrayZ, length * sizeof (int));
+    else
+      dynamic_coords.extend (coords_);
+  }
 
   int& operator [] (unsigned idx)
   {
     if (unlikely (idx >= HB_VAR_COMPOSITE_MAX_AXES))
       return Crap(int);
-    if (coords.length < idx + 1)
-      coords.resize (idx + 1);
-    return coords[idx];
+
+    if (length <= ARRAY_LENGTH (static_coords))
+    {
+      if (idx < ARRAY_LENGTH (static_coords))
+      {
+        while (length <= idx)
+	  static_coords[length++] = 0;
+	return static_coords[idx];
+      }
+      else
+      {
+        dynamic_coords.extend (hb_array (static_coords, length));
+      }
+    }
+
+    if (dynamic_coords.length <= idx &&
+	unlikely (!dynamic_coords.resize (idx + 1)))
+      return Crap(int);
+    return dynamic_coords.arrayZ[idx];
   }
 
   hb_array_t<int> get_coords ()
-  { return coords.as_array (); }
+  { return dynamic_coords ? dynamic_coords.as_array () : hb_array (static_coords, length); }
 
-  hb_vector_t<int> coords;
+  unsigned length;
+  int static_coords[32];
+  hb_vector_t<int> dynamic_coords;
 };