[gtk+] Manipulate bits more efficiently

[Matthias Clasen <matthiasc src gnome org>]

commit d7dd6eccd500402ac51c2a3d2b8f768acfa75d4a
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Sep 9 14:00:49 2015 -0400

    Manipulate bits more efficiently
    
    The function to translate GtkCssChange enum values to the PARENT
    ones is called very frequently. This patch speeds it up tremendously.
    The callgrind instruction count for this function in the listbox
    demo goes from 108M to 7M.

 gtk/gtkcsstypes.c |   40 +++++++++++++++++++---------------------
 1 files changed, 19 insertions(+), 21 deletions(-)
---
diff --git a/gtk/gtkcsstypes.c b/gtk/gtkcsstypes.c
index 3553683..3a84870 100644
--- a/gtk/gtkcsstypes.c
+++ b/gtk/gtkcsstypes.c
@@ -70,28 +70,26 @@ _gtk_css_change_for_sibling (GtkCssChange match)
 GtkCssChange
 _gtk_css_change_for_child (GtkCssChange match)
 {
-  static const GtkCssChangeTranslation table[] = {
-    { GTK_CSS_CHANGE_CLASS, GTK_CSS_CHANGE_PARENT_CLASS },
-    { GTK_CSS_CHANGE_NAME, GTK_CSS_CHANGE_PARENT_NAME },
-    { GTK_CSS_CHANGE_ID, GTK_CSS_CHANGE_PARENT_ID },
-    { GTK_CSS_CHANGE_FIRST_CHILD, GTK_CSS_CHANGE_PARENT_FIRST_CHILD },
-    { GTK_CSS_CHANGE_LAST_CHILD, GTK_CSS_CHANGE_PARENT_LAST_CHILD },
-    { GTK_CSS_CHANGE_NTH_CHILD, GTK_CSS_CHANGE_PARENT_NTH_CHILD },
-    { GTK_CSS_CHANGE_NTH_LAST_CHILD, GTK_CSS_CHANGE_PARENT_NTH_LAST_CHILD },
-    { GTK_CSS_CHANGE_STATE, GTK_CSS_CHANGE_PARENT_STATE },
-    { GTK_CSS_CHANGE_SIBLING_CLASS, GTK_CSS_CHANGE_PARENT_SIBLING_CLASS },
-    { GTK_CSS_CHANGE_SIBLING_NAME, GTK_CSS_CHANGE_PARENT_SIBLING_NAME },
-    { GTK_CSS_CHANGE_SIBLING_ID, GTK_CSS_CHANGE_PARENT_SIBLING_ID },
-    { GTK_CSS_CHANGE_SIBLING_FIRST_CHILD, GTK_CSS_CHANGE_PARENT_SIBLING_FIRST_CHILD },
-    { GTK_CSS_CHANGE_SIBLING_LAST_CHILD, GTK_CSS_CHANGE_PARENT_SIBLING_LAST_CHILD },
-    { GTK_CSS_CHANGE_SIBLING_NTH_CHILD, GTK_CSS_CHANGE_PARENT_SIBLING_NTH_CHILD },
-    { GTK_CSS_CHANGE_SIBLING_NTH_LAST_CHILD, GTK_CSS_CHANGE_PARENT_SIBLING_NTH_LAST_CHILD },
-    { GTK_CSS_CHANGE_SIBLING_STATE, GTK_CSS_CHANGE_PARENT_SIBLING_STATE },
-    { GTK_CSS_CHANGE_SOURCE, 0 },
-    { GTK_CSS_CHANGE_PARENT_STYLE, 0 }
-  };
-
-  return gtk_css_change_translate (match, table, G_N_ELEMENTS (table)); 
+#define BASE_STATES ( GTK_CSS_CHANGE_CLASS \
+                    | GTK_CSS_CHANGE_NAME \
+                    | GTK_CSS_CHANGE_ID \
+                    | GTK_CSS_CHANGE_FIRST_CHILD \
+                    | GTK_CSS_CHANGE_LAST_CHILD \
+                    | GTK_CSS_CHANGE_NTH_CHILD \
+                    | GTK_CSS_CHANGE_NTH_LAST_CHILD \
+                    | GTK_CSS_CHANGE_STATE \
+                    | GTK_CSS_CHANGE_SIBLING_CLASS \
+                    | GTK_CSS_CHANGE_SIBLING_NAME \
+                    | GTK_CSS_CHANGE_SIBLING_ID \
+                    | GTK_CSS_CHANGE_SIBLING_FIRST_CHILD \
+                    | GTK_CSS_CHANGE_SIBLING_LAST_CHILD \
+                    | GTK_CSS_CHANGE_SIBLING_NTH_CHILD \
+                    | GTK_CSS_CHANGE_SIBLING_NTH_LAST_CHILD \
+                    | GTK_CSS_CHANGE_SIBLING_STATE )
+
+#define PARENT_SHIFT 16
+
+  return (match & ~(BASE_STATES|GTK_CSS_CHANGE_SOURCE|GTK_CSS_CHANGE_PARENT_STYLE)) | ((match & BASE_STATES) 
<< PARENT_SHIFT);
 }
 
 void