From: Matthias Clasen <mclasen@redhat.com>
Date: Tue, 7 Aug 2012 04:38:48 +0000 (-0400)
Subject: Optimize gtk_widget_path_copy() by preallocating "elems" array
X-Git-Tag: archive/raspbian/3.24.39-1+rpi1~1^2~65^2~39^2~16710
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=f89d5c828038654802526c9ea68e6fb52fa461d3;p=gtk%2B3.0.git

Optimize gtk_widget_path_copy() by preallocating "elems" array

gtk_widget_path_copy() currently calls g_array_append_val() in a loop,
which is inefficient due to reallocating the array's memory. Calling
g_array_set_size() before entering the loop reduces the number of CPU
cycles used by roughly 30%.

Patch by John Lindgren,
https://bugzilla.gnome.org/show_bug.cgi?id=679978
---

diff --git a/gtk/gtkwidgetpath.c b/gtk/gtkwidgetpath.c
index 00afbe0b9e..855902fd68 100644
--- a/gtk/gtkwidgetpath.c
+++ b/gtk/gtkwidgetpath.c
@@ -174,15 +174,16 @@ gtk_widget_path_copy (const GtkWidgetPath *path)
 
   new_path = gtk_widget_path_new ();
 
+  g_array_set_size (new_path->elems, path->elems->len);
+
   for (i = 0; i < path->elems->len; i++)
     {
-      GtkPathElement *elem, new;
+      GtkPathElement *elem, *dest;
 
       elem = &g_array_index (path->elems, GtkPathElement, i);
+      dest = &g_array_index (new_path->elems, GtkPathElement, i);
 
-      gtk_path_element_copy (&new, elem);
-
-      g_array_append_val (new_path->elems, new);
+      gtk_path_element_copy (dest, elem);
     }
 
   return new_path;