/* 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

 * @title: 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_new (GST_TYPE_TYPE_FIND_FACTORY, 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);

}