(Fmodify_frame_parameters): Use alist in reverse order.

1 files changed, 29 insertions, 7 deletions

diff --git a/src/frame.c b/src/frame.c
index c88262c7bae..31b5b854348 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -1816,13 +1816,35 @@ so that `frame-parameters' will return them.")
     IT_set_frame_parameters (f, alist);
   else
 #endif
-    for (tail = alist; !EQ (tail, Qnil); tail = Fcdr (tail))
-      {
-        elt = Fcar (tail);
-        prop = Fcar (elt);
-        val = Fcdr (elt);
-        store_frame_param (f, prop, val);
-      }
+    {
+      int length = XINT (Flength (alist));
+      int i;
+      Lisp_Object *parms
+        = (Lisp_Object *) alloca (length * sizeof (Lisp_Object));
+      Lisp_Object *values
+        = (Lisp_Object *) alloca (length * sizeof (Lisp_Object));
+
+      /* Extract parm names and values into those vectors.  */
+
+      i = 0;
+      for (tail = alist; CONSP (tail); tail = Fcdr (tail))
+        {
+          Lisp_Object elt, prop, val;
+
+          elt = Fcar (tail);
+          parms[i] = Fcar (elt);
+          values[i] = Fcdr (elt);
+          i++;
+        }
+
+      /* Now process them in reverse of specified order.  */
+      for (i--; i >= 0; i--)
+        {
+          prop = parms[i];
+          val = values[i];
+          store_frame_param (f, prop, val);
+        }
+    }
 
   return Qnil;
 }