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/* GStreamer
* Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
*
* gsttypefindfactory.c: typefinding subsystem
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gsttypefindfactory
* @short_description: Information about registered typefind functions
*
* These functions allow querying informations about registered typefind
* functions. How to create and register these functions is described in
* the section <link linkend="gstreamer-Writing-typefind-functions">
* "Writing typefind functions"</link>.
*
* <example>
* <title>how to write a simple typefinder</title>
* <programlisting>
* typedef struct {
* guint8 *data;
* guint size;
* guint probability;
* GstCaps *data;
* } MyTypeFind;
* static void
* my_peek (gpointer data, gint64 offset, guint size)
* {
* MyTypeFind *find = (MyTypeFind *) data;
* if (offset &gt;= 0 &amp;&amp; offset + size &lt;= find->size) {
* return find->data + offset;
* }
* return NULL;
* }
* static void
* my_suggest (gpointer data, guint probability, GstCaps *caps)
* {
* MyTypeFind *find = (MyTypeFind *) data;
* if (probability &gt; find->probability) {
* find->probability = probability;
* gst_caps_replace (&amp;find->caps, caps);
* }
* }
* static GstCaps *
* find_type (guint8 *data, guint size)
* {
* GList *walk, *type_list;
* MyTypeFind find = {data, size, 0, NULL};
* GstTypeFind gst_find = {my_peek, my_suggest, &amp;find, };
* walk = type_list = gst_type_find_factory_get_list ();
* while (walk) {
* GstTypeFindFactory *factory = GST_TYPE_FIND_FACTORY (walk->data);
* walk = g_list_next (walk)
* gst_type_find_factory_call_function (factory, &amp;gst_find);
* }
* g_list_free (type_list);
* return find.caps;
* };
* </programlisting>
* </example>
*
* The above example shows how to write a very simple typefinder that
* identifies the given data. You can get quite a bit more complicated than
* that though.
*
* Last reviewed on 2005-11-09 (0.9.4)
*/
#include "gst_private.h"
#include "gstinfo.h"
#include "gsttypefind.h"
#include "gsttypefindfactory.h"
#include "gstregistry.h"
GST_DEBUG_CATEGORY (type_find_debug);
#define GST_CAT_DEFAULT type_find_debug
static void gst_type_find_factory_dispose (GObject * object);
#define _do_init \
{ \
GST_DEBUG_CATEGORY_INIT (type_find_debug, "GST_TYPEFIND", \
GST_DEBUG_FG_GREEN, "typefinding subsystem"); \
}
#define gst_type_find_factory_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstTypeFindFactory, gst_type_find_factory,
GST_TYPE_PLUGIN_FEATURE, _do_init);
static void
gst_type_find_factory_class_init (GstTypeFindFactoryClass * klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
object_class->dispose = gst_type_find_factory_dispose;
}
static void
gst_type_find_factory_init (GstTypeFindFactory * factory)
{
factory->user_data = factory;
factory->user_data_notify = NULL;
}
static void
gst_type_find_factory_dispose (GObject * object)
{
GstTypeFindFactory *factory = GST_TYPE_FIND_FACTORY (object);
if (factory->caps) {
gst_caps_unref (factory->caps);
factory->caps = NULL;
}
if (factory->extensions) {
g_strfreev (factory->extensions);
factory->extensions = NULL;
}
if (factory->user_data_notify && factory->user_data) {
factory->user_data_notify (factory->user_data);
factory->user_data = NULL;
}
G_OBJECT_CLASS (parent_class)->dispose (object);
}
/**
* gst_type_find_factory_get_list:
*
* Gets the list of all registered typefind factories. You must free the
* list using gst_plugin_feature_list_free().
*
* The returned factories are sorted by highest rank first, and then by
* factory name.
*
* Free-function: gst_plugin_feature_list_free
*
* Returns: (transfer full) (element-type Gst.TypeFindFactory): the list of all
* registered #GstTypeFindFactory.
*/
GList *
gst_type_find_factory_get_list (void)
{
return gst_registry_get_feature_list (gst_registry_get (),
GST_TYPE_TYPE_FIND_FACTORY);
}
/**
* gst_type_find_factory_get_caps:
* @factory: A #GstTypeFindFactory
*
* Gets the #GstCaps associated with a typefind factory.
*
* Returns: (transfer none): the #GstCaps associated with this factory
*/
GstCaps *
gst_type_find_factory_get_caps (GstTypeFindFactory * factory)
{
g_return_val_if_fail (GST_IS_TYPE_FIND_FACTORY (factory), NULL);
return factory->caps;
}
/**
* gst_type_find_factory_get_extensions:
* @factory: A #GstTypeFindFactory
*
* Gets the extensions associated with a #GstTypeFindFactory. The returned
* array should not be changed. If you need to change stuff in it, you should
* copy it using g_strdupv(). This function may return NULL to indicate
* a 0-length list.
*
* Returns: (transfer none) (array zero-terminated=1) (element-type utf8): a
* NULL-terminated array of extensions associated with this factory
*/
const gchar *const *
gst_type_find_factory_get_extensions (GstTypeFindFactory * factory)
{
g_return_val_if_fail (GST_IS_TYPE_FIND_FACTORY (factory), NULL);
return (const gchar * const *) factory->extensions;
}
/**
* gst_type_find_factory_call_function:
* @factory: A #GstTypeFindFactory
* @find: (transfer none): a properly setup #GstTypeFind entry. The get_data
* and suggest_type members must be set.
*
* Calls the #GstTypeFindFunction associated with this factory.
*/
void
gst_type_find_factory_call_function (GstTypeFindFactory * factory,
GstTypeFind * find)
{
GstTypeFindFactory *new_factory;
g_return_if_fail (GST_IS_TYPE_FIND_FACTORY (factory));
g_return_if_fail (find != NULL);
g_return_if_fail (find->peek != NULL);
g_return_if_fail (find->suggest != NULL);
new_factory =
GST_TYPE_FIND_FACTORY (gst_plugin_feature_load (GST_PLUGIN_FEATURE
(factory)));
if (new_factory) {
if (new_factory->function)
new_factory->function (find, new_factory->user_data);
gst_object_unref (new_factory);
}
}
/**
* gst_type_find_factory_has_function:
* @factory: A #GstTypeFindFactory
*
* Check whether the factory has a typefind function. Typefind factories
* without typefind functions are a last-effort fallback mechanism to
* e.g. assume a certain media type based on the file extension.
*
* Returns: TRUE if the factory has a typefind functions set, otherwise FALSE
*/
gboolean
gst_type_find_factory_has_function (GstTypeFindFactory * factory)
{
g_return_val_if_fail (GST_IS_TYPE_FIND_FACTORY (factory), FALSE);
return (factory->function != NULL);
}