--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gstreamer_core/gst/gstfilter.c	Thu Dec 17 08:53:32 2009 +0200
@@ -0,0 +1,92 @@
+/* GStreamer
+ * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+/**
+ * SECTION:gstfilter
+ * @short_description: A utility function to filter GLists.
+ *
+ * <example>
+ * <title>Filtering a list</title>
+ *   <programlisting>
+ *     GList *node;
+ *     GstObject *result = NULL;
+ *     
+ *     node = gst_filter_run (list, (GstFilterFunc) my_filter, TRUE, NULL);
+ *     if (node) {
+ *       result = GST_OBJECT (node->data);
+ *       gst_object_ref (result);
+ *       gst_list_free (node);
+ *     }
+ *   </programlisting>
+ * </example>
+ */
+#include "gst_private.h"
+#include <gst/gstfilter.h>
+
+/**
+ * gst_filter_run:
+ * @list: a linked list
+ * @func: the function to execute for each item
+ * @first: flag to stop execution after a successful item
+ * @user_data: user data
+ *
+ * Iterates over the elements in @list, calling @func with the
+ * list item data for each item.  If @func returns TRUE, @data is
+ * prepended to the list of results returned.  If @first is true,
+ * the search is halted after the first result is found.
+ *
+ * Since gst_filter_run() knows nothing about the type of @data, no
+ * reference will be taken (if @data refers to an object) and no copy of
+ * @data wil be made in any other way when prepending @data to the list of
+ * results.
+ *
+ * Returns: the list of results. Free with g_list_free() when no longer needed
+ * (the data contained in the list is a flat copy and does need to be
+ * unreferenced or freed).
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+GList *
+gst_filter_run (const GList * list, GstFilterFunc func, gboolean first,
+    gpointer user_data)
+{
+  const GList *walk = list;
+  GList *result = NULL;
+
+  while (walk) {
+    gboolean res = TRUE;
+    gpointer data = walk->data;
+
+    walk = g_list_next (walk);
+
+    if (func)
+      res = func (data, user_data);
+
+    if (res) {
+      result = g_list_prepend (result, data);
+
+      if (first)
+        break;
+    }
+  }
+
+  return result;
+}