gst/gsttypefind.c - imx-gstreamer - Git at Google

 /* GStreamer
  * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
  *
  * gsttypefind.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:gsttypefind
  * @short_description: Stream type detection
  *
  * The following functions allow you to detect the media type of an unknown
  * stream.
  */

 #include "gst_private.h"
 #include "gstinfo.h"
 #include "gsttypefind.h"
 #include "gstregistry.h"
 #include "gsttypefindfactory.h"

 GST_DEBUG_CATEGORY_EXTERN (type_find_debug);
 #define GST_CAT_DEFAULT type_find_debug

 G_DEFINE_POINTER_TYPE (GstTypeFind, gst_type_find);

 /**
  * gst_type_find_register:
  * @plugin: (allow-none): A #GstPlugin, or %NULL for a static typefind function
  * @name: The name for registering
  * @rank: The rank (or importance) of this typefind function
  * @func: The #GstTypeFindFunction to use
  * @extensions: (allow-none): Optional comma-separated list of extensions
  *     that could belong to this type
  * @possible_caps: Optionally the caps that could be returned when typefinding
  *                 succeeds
  * @data: Optional user data. This user data must be available until the plugin
  *        is unloaded.
  * @data_notify: a #GDestroyNotify that will be called on @data when the plugin
  *        is unloaded.
  *
  * Registers a new typefind function to be used for typefinding. After
  * registering this function will be available for typefinding.
  * This function is typically called during an element's plugin initialization.
  *
  * Returns: %TRUE on success, %FALSE otherwise
  */
 gboolean
 gst_type_find_register (GstPlugin * plugin, const gchar * name, guint rank,
     GstTypeFindFunction func, const gchar * extensions,
     GstCaps * possible_caps, gpointer data, GDestroyNotify data_notify)
 {
   GstTypeFindFactory *factory;

   g_return_val_if_fail (name != NULL, FALSE);

   GST_INFO ("registering typefind function for %s", name);

   factory = g_object_newv (GST_TYPE_TYPE_FIND_FACTORY, 0, NULL);
   GST_DEBUG_OBJECT (factory, "using new typefind factory for %s", name);

   gst_plugin_feature_set_name (GST_PLUGIN_FEATURE_CAST (factory), name);
   gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE_CAST (factory), rank);

   if (extensions)
     factory->extensions = g_strsplit (extensions, ",", -1);

   gst_caps_replace (&factory->caps, possible_caps);
   factory->function = func;
   factory->user_data = data;
   factory->user_data_notify = data_notify;
   if (plugin && plugin->desc.name) {
     GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = plugin->desc.name; /* interned string */
     GST_PLUGIN_FEATURE_CAST (factory)->plugin = plugin;
     g_object_add_weak_pointer ((GObject *) plugin,
         (gpointer *) & GST_PLUGIN_FEATURE_CAST (factory)->plugin);
   } else {
     GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL";
     GST_PLUGIN_FEATURE_CAST (factory)->plugin = NULL;
   }
   GST_PLUGIN_FEATURE_CAST (factory)->loaded = TRUE;

   gst_registry_add_feature (gst_registry_get (),
       GST_PLUGIN_FEATURE_CAST (factory));

   return TRUE;
 }

 /*** typefind function interface **********************************************/

 /**
  * gst_type_find_peek:
  * @find: The #GstTypeFind object the function was called with
  * @offset: The offset
  * @size: The number of bytes to return
  *
  * Returns the @size bytes of the stream to identify beginning at offset. If
  * offset is a positive number, the offset is relative to the beginning of the
  * stream, if offset is a negative number the offset is relative to the end of
  * the stream. The returned memory is valid until the typefinding function
  * returns and must not be freed.
  *
  * Returns: (transfer none) (array length=size) (nullable): the
  *     requested data, or %NULL if that data is not available.
  */
 const guint8 *
 gst_type_find_peek (GstTypeFind * find, gint64 offset, guint size)
 {
   g_return_val_if_fail (find->peek != NULL, NULL);

   return find->peek (find->data, offset, size);
 }

 /**
  * gst_type_find_suggest:
  * @find: The #GstTypeFind object the function was called with
  * @probability: The probability in percent that the suggestion is right
  * @caps: The fixed #GstCaps to suggest
  *
  * If a #GstTypeFindFunction calls this function it suggests the caps with the
  * given probability. A #GstTypeFindFunction may supply different suggestions
  * in one call.
  * It is up to the caller of the #GstTypeFindFunction to interpret these values.
  */
 void
 gst_type_find_suggest (GstTypeFind * find, guint probability, GstCaps * caps)
 {
   g_return_if_fail (find->suggest != NULL);
   g_return_if_fail (probability <= 100);
   g_return_if_fail (caps != NULL);
   g_return_if_fail (gst_caps_is_fixed (caps));

   find->suggest (find->data, probability, caps);
 }

 /**
  * gst_type_find_suggest_simple:
  * @find: The #GstTypeFind object the function was called with
  * @probability: The probability in percent that the suggestion is right
  * @media_type: the media type of the suggested caps
  * @fieldname: (allow-none): first field of the suggested caps, or %NULL
  * @...: additional arguments to the suggested caps in the same format as the
  *     arguments passed to gst_structure_new() (ie. triplets of field name,
  *     field GType and field value)
  *
  * If a #GstTypeFindFunction calls this function it suggests the caps with the
  * given probability. A #GstTypeFindFunction may supply different suggestions
  * in one call. It is up to the caller of the #GstTypeFindFunction to interpret
  * these values.
  *
  * This function is similar to gst_type_find_suggest(), only that instead of
  * passing a #GstCaps argument you can create the caps on the fly in the same
  * way as you can with gst_caps_new_simple().
  *
  * Make sure you terminate the list of arguments with a %NULL argument and that
  * the values passed have the correct type (in terms of width in bytes when
  * passed to the vararg function - this applies particularly to gdouble and
  * guint64 arguments).
  */
 void
 gst_type_find_suggest_simple (GstTypeFind * find, guint probability,
     const char *media_type, const char *fieldname, ...)
 {
   GstStructure *structure;
   va_list var_args;
   GstCaps *caps;

   g_return_if_fail (find->suggest != NULL);
   g_return_if_fail (probability <= 100);
   g_return_if_fail (media_type != NULL);

   caps = gst_caps_new_empty ();

   va_start (var_args, fieldname);
   structure = gst_structure_new_valist (media_type, fieldname, var_args);
   va_end (var_args);

   gst_caps_append_structure (caps, structure);
   g_return_if_fail (gst_caps_is_fixed (caps));

   find->suggest (find->data, probability, caps);
   gst_caps_unref (caps);
 }

 /**
  * gst_type_find_get_length:
  * @find: The #GstTypeFind the function was called with
  *
  * Get the length of the data stream.
  *
  * Returns: The length of the data stream, or 0 if it is not available.
  */
 guint64
 gst_type_find_get_length (GstTypeFind * find)
 {
   if (find->get_length == NULL)
     return 0;

   return find->get_length (find->data);
 }
	/* GStreamer
	* Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
	*
	* gsttypefind.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:gsttypefind
	* @short_description: Stream type detection
	*
	* The following functions allow you to detect the media type of an unknown
	* stream.
	*/

	#include "gst_private.h"
	#include "gstinfo.h"
	#include "gsttypefind.h"
	#include "gstregistry.h"
	#include "gsttypefindfactory.h"

	GST_DEBUG_CATEGORY_EXTERN (type_find_debug);
	#define GST_CAT_DEFAULT type_find_debug

	G_DEFINE_POINTER_TYPE (GstTypeFind, gst_type_find);

	/**
	* gst_type_find_register:
	* @plugin: (allow-none): A #GstPlugin, or %NULL for a static typefind function
	* @name: The name for registering
	* @rank: The rank (or importance) of this typefind function
	* @func: The #GstTypeFindFunction to use
	* @extensions: (allow-none): Optional comma-separated list of extensions
	* that could belong to this type
	* @possible_caps: Optionally the caps that could be returned when typefinding
	* succeeds
	* @data: Optional user data. This user data must be available until the plugin
	* is unloaded.
	* @data_notify: a #GDestroyNotify that will be called on @data when the plugin
	* is unloaded.
	*
	* Registers a new typefind function to be used for typefinding. After
	* registering this function will be available for typefinding.
	* This function is typically called during an element's plugin initialization.
	*
	* Returns: %TRUE on success, %FALSE otherwise
	*/
	gboolean
	gst_type_find_register (GstPlugin * plugin, const gchar * name, guint rank,
	GstTypeFindFunction func, const gchar * extensions,
	GstCaps * possible_caps, gpointer data, GDestroyNotify data_notify)
	{
	GstTypeFindFactory *factory;

	g_return_val_if_fail (name != NULL, FALSE);

	GST_INFO ("registering typefind function for %s", name);

	factory = g_object_newv (GST_TYPE_TYPE_FIND_FACTORY, 0, NULL);
	GST_DEBUG_OBJECT (factory, "using new typefind factory for %s", name);

	gst_plugin_feature_set_name (GST_PLUGIN_FEATURE_CAST (factory), name);
	gst_plugin_feature_set_rank (GST_PLUGIN_FEATURE_CAST (factory), rank);

	if (extensions)
	factory->extensions = g_strsplit (extensions, ",", -1);

	gst_caps_replace (&factory->caps, possible_caps);
	factory->function = func;
	factory->user_data = data;
	factory->user_data_notify = data_notify;
	if (plugin && plugin->desc.name) {
	GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = plugin->desc.name; /* interned string */
	GST_PLUGIN_FEATURE_CAST (factory)->plugin = plugin;
	g_object_add_weak_pointer ((GObject *) plugin,
	(gpointer *) & GST_PLUGIN_FEATURE_CAST (factory)->plugin);
	} else {
	GST_PLUGIN_FEATURE_CAST (factory)->plugin_name = "NULL";
	GST_PLUGIN_FEATURE_CAST (factory)->plugin = NULL;
	}
	GST_PLUGIN_FEATURE_CAST (factory)->loaded = TRUE;

	gst_registry_add_feature (gst_registry_get (),
	GST_PLUGIN_FEATURE_CAST (factory));

	return TRUE;
	}

	/* typefind function interface ********************************************/

	/**
	* gst_type_find_peek:
	* @find: The #GstTypeFind object the function was called with
	* @offset: The offset
	* @size: The number of bytes to return
	*
	* Returns the @size bytes of the stream to identify beginning at offset. If
	* offset is a positive number, the offset is relative to the beginning of the
	* stream, if offset is a negative number the offset is relative to the end of
	* the stream. The returned memory is valid until the typefinding function
	* returns and must not be freed.
	*
	* Returns: (transfer none) (array length=size) (nullable): the
	* requested data, or %NULL if that data is not available.
	*/
	const guint8 *
	gst_type_find_peek (GstTypeFind * find, gint64 offset, guint size)
	{
	g_return_val_if_fail (find->peek != NULL, NULL);

	return find->peek (find->data, offset, size);
	}

	/**
	* gst_type_find_suggest:
	* @find: The #GstTypeFind object the function was called with
	* @probability: The probability in percent that the suggestion is right
	* @caps: The fixed #GstCaps to suggest
	*
	* If a #GstTypeFindFunction calls this function it suggests the caps with the
	* given probability. A #GstTypeFindFunction may supply different suggestions
	* in one call.
	* It is up to the caller of the #GstTypeFindFunction to interpret these values.
	*/
	void
	gst_type_find_suggest (GstTypeFind * find, guint probability, GstCaps * caps)
	{
	g_return_if_fail (find->suggest != NULL);
	g_return_if_fail (probability <= 100);
	g_return_if_fail (caps != NULL);
	g_return_if_fail (gst_caps_is_fixed (caps));

	find->suggest (find->data, probability, caps);
	}

	/**
	* gst_type_find_suggest_simple:
	* @find: The #GstTypeFind object the function was called with
	* @probability: The probability in percent that the suggestion is right
	* @media_type: the media type of the suggested caps
	* @fieldname: (allow-none): first field of the suggested caps, or %NULL
	* @...: additional arguments to the suggested caps in the same format as the
	* arguments passed to gst_structure_new() (ie. triplets of field name,
	* field GType and field value)
	*
	* If a #GstTypeFindFunction calls this function it suggests the caps with the
	* given probability. A #GstTypeFindFunction may supply different suggestions
	* in one call. It is up to the caller of the #GstTypeFindFunction to interpret
	* these values.
	*
	* This function is similar to gst_type_find_suggest(), only that instead of
	* passing a #GstCaps argument you can create the caps on the fly in the same
	* way as you can with gst_caps_new_simple().
	*
	* Make sure you terminate the list of arguments with a %NULL argument and that
	* the values passed have the correct type (in terms of width in bytes when
	* passed to the vararg function - this applies particularly to gdouble and
	* guint64 arguments).
	*/
	void
	gst_type_find_suggest_simple (GstTypeFind * find, guint probability,
	const char media_type, const char fieldname, ...)
	{
	GstStructure *structure;
	va_list var_args;
	GstCaps *caps;

	g_return_if_fail (find->suggest != NULL);
	g_return_if_fail (probability <= 100);
	g_return_if_fail (media_type != NULL);

	caps = gst_caps_new_empty ();

	va_start (var_args, fieldname);
	structure = gst_structure_new_valist (media_type, fieldname, var_args);
	va_end (var_args);

	gst_caps_append_structure (caps, structure);
	g_return_if_fail (gst_caps_is_fixed (caps));

	find->suggest (find->data, probability, caps);
	gst_caps_unref (caps);
	}

	/**
	* gst_type_find_get_length:
	* @find: The #GstTypeFind the function was called with
	*
	* Get the length of the data stream.
	*
	* Returns: The length of the data stream, or 0 if it is not available.
	*/
	guint64
	gst_type_find_get_length (GstTypeFind * find)
	{
	if (find->get_length == NULL)
	return 0;

	return find->get_length (find->data);
	}