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/* 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).
*/
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;
}
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