[gtk/wip/baedert/css-values: 8/13] cssnumbervalue: Add early-outs to transition code

[Timm Bäder <baedert src gnome org>]

commit 9ba973c4f7c9cbb19c91d6e22da1321e05b808da
Author: Timm Bäder <mail baedert org>
Date:   Wed Jan 8 09:42:23 2020 +0100

    cssnumbervalue: Add early-outs to transition code
    
    we don't need to do the calculation at all if the progress is 0 or 1
    anyway.
    
    We also sometimes transition from 0 to 0 etc., so we can short-circuit
    that as well by doing the fast pointer-equality check and relying on the
    singletons.

 gtk/gtkcssnumbervalue.c | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/gtk/gtkcssnumbervalue.c b/gtk/gtkcssnumbervalue.c
index f5e574c81d..83fa257f01 100644
--- a/gtk/gtkcssnumbervalue.c
+++ b/gtk/gtkcssnumbervalue.c
@@ -115,6 +115,15 @@ gtk_css_number_value_transition (GtkCssValue *start,
 {
   GtkCssValue *result, *mul_start, *mul_end;
 
+  if (progress == 0)
+    return _gtk_css_value_ref (start);
+
+  if (progress == 1)
+    return _gtk_css_value_ref (end);
+
+  if (start == end)
+    return _gtk_css_value_ref (start);
+
   mul_start = gtk_css_number_value_multiply (start, 1 - progress);
   mul_end = gtk_css_number_value_multiply (end, progress);