/* 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;

}