``` gstmeta.c:500: Warning: Gst: gst_meta_info_new: return value: Invalid non-constant return of bare structure or union; register as boxed type or (skip) ``` Skip this for now Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/6147>
		
			
				
	
	
		
			811 lines
		
	
	
		
			22 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			811 lines
		
	
	
		
			22 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* GStreamer
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|  * Copyright (C) 2011 Wim Taymans <wim.taymans@gmail.com>
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|  *
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|  * gstmeta.c: metadata operations
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|  *
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|  * This library is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU Library General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2 of the License, or (at your option) any later version.
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|  *
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|  * This library is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * Library General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Library General Public
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|  * License along with this library; if not, write to the
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|  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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|  * Boston, MA 02110-1301, USA.
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|  */
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| 
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| /**
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|  * SECTION:gstmeta
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|  * @title: GstMeta
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|  * @short_description: Buffer metadata
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|  *
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|  * The #GstMeta structure should be included as the first member of a #GstBuffer
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|  * metadata structure. The structure defines the API of the metadata and should
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|  * be accessible to all elements using the metadata.
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|  *
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|  * A metadata API is registered with gst_meta_api_type_register() which takes a
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|  * name for the metadata API and some tags associated with the metadata.
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|  * With gst_meta_api_type_has_tag() one can check if a certain metadata API
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|  * contains a given tag.
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|  *
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|  * Multiple implementations of a metadata API can be registered.
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|  * To implement a metadata API, gst_meta_register() should be used. This
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|  * function takes all parameters needed to create, free and transform metadata
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|  * along with the size of the metadata. The function returns a #GstMetaInfo
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|  * structure that contains the information for the implementation of the API.
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|  *
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|  * A specific implementation can be retrieved by name with gst_meta_get_info().
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|  *
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|  * See #GstBuffer for how the metadata can be added, retrieved and removed from
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|  * buffers.
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|  */
 | |
| #include "gst_private.h"
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| 
 | |
| #include "gstbuffer.h"
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| #include "gstmeta.h"
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| #include "gstinfo.h"
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| #include "gstutils.h"
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| #include "gstquark.h"
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| 
 | |
| static GHashTable *metainfo = NULL;
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| static GRWLock lock;
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| 
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| GQuark _gst_meta_transform_copy;
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| GQuark _gst_meta_tag_memory;
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| GQuark _gst_meta_tag_memory_reference;
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| 
 | |
| typedef struct
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| {
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|   GstMetaInfo info;
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|   GstCustomMetaTransformFunction custom_transform_func;
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|   gpointer custom_transform_user_data;
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|   GDestroyNotify custom_transform_destroy_notify;
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|   gboolean is_custom;
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| } GstMetaInfoImpl;
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| 
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| static void
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| free_info (gpointer data)
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| {
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|   g_free (data);
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| }
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| 
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| void
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| _priv_gst_meta_initialize (void)
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| {
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|   g_rw_lock_init (&lock);
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|   metainfo = g_hash_table_new_full (g_str_hash, g_str_equal, NULL, free_info);
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| 
 | |
|   _gst_meta_transform_copy = g_quark_from_static_string ("gst-copy");
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|   _gst_meta_tag_memory = g_quark_from_static_string ("memory");
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|   _gst_meta_tag_memory_reference =
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|       g_quark_from_static_string ("memory-reference");
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| }
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| 
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| static gboolean
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| notify_custom (gchar * key, GstMetaInfo * info, gpointer unused)
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| {
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|   GstMetaInfoImpl *impl = (GstMetaInfoImpl *) info;
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| 
 | |
|   if (impl->is_custom) {
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|     if (impl->custom_transform_destroy_notify)
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|       impl->custom_transform_destroy_notify (impl->custom_transform_user_data);
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|   }
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|   return TRUE;
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| }
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| 
 | |
| void
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| _priv_gst_meta_cleanup (void)
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| {
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|   if (metainfo != NULL) {
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|     g_hash_table_foreach_remove (metainfo, (GHRFunc) notify_custom, NULL);
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|     g_hash_table_unref (metainfo);
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|     metainfo = NULL;
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|   }
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| }
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| 
 | |
| /**
 | |
|  * gst_meta_api_type_register:
 | |
|  * @api: an API to register
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|  * @tags: (array zero-terminated=1): tags for @api
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|  *
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|  * Register and return a GType for the @api and associate it with
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|  * @tags.
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|  *
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|  * Returns: a unique GType for @api.
 | |
|  */
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| GType
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| gst_meta_api_type_register (const gchar * api, const gchar ** tags)
 | |
| {
 | |
|   GType type;
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| 
 | |
|   g_return_val_if_fail (api != NULL, 0);
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|   g_return_val_if_fail (tags != NULL, 0);
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| 
 | |
|   GST_CAT_DEBUG (GST_CAT_META, "register API \"%s\"", api);
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|   type = g_pointer_type_register_static (api);
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| 
 | |
|   if (type != G_TYPE_INVALID) {
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|     gint i;
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| 
 | |
|     for (i = 0; tags[i]; i++) {
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|       GST_CAT_DEBUG (GST_CAT_META, "  adding tag \"%s\"", tags[i]);
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|       g_type_set_qdata (type, g_quark_from_string (tags[i]),
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|           GINT_TO_POINTER (TRUE));
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|     }
 | |
|   }
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| 
 | |
|   g_type_set_qdata (type, GST_QUARK (TAGS), g_strdupv ((gchar **) tags));
 | |
| 
 | |
|   return type;
 | |
| }
 | |
| 
 | |
| static gboolean
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| custom_init_func (GstMeta * meta, gpointer params, GstBuffer * buffer)
 | |
| {
 | |
|   GstCustomMeta *cmeta = (GstCustomMeta *) meta;
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| 
 | |
|   cmeta->structure = gst_structure_new_empty (g_type_name (meta->info->type));
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| 
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|   gst_structure_set_parent_refcount (cmeta->structure,
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|       &GST_MINI_OBJECT_REFCOUNT (buffer));
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| 
 | |
|   return TRUE;
 | |
| }
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| 
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| static void
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| custom_free_func (GstMeta * meta, GstBuffer * buffer)
 | |
| {
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|   GstCustomMeta *cmeta = (GstCustomMeta *) meta;
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| 
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|   gst_structure_set_parent_refcount (cmeta->structure, NULL);
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|   gst_structure_free (cmeta->structure);
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| }
 | |
| 
 | |
| static gboolean
 | |
| custom_transform_func (GstBuffer * transbuf, GstMeta * meta,
 | |
|     GstBuffer * buffer, GQuark type, gpointer data)
 | |
| {
 | |
|   GstCustomMeta *custom, *cmeta = (GstCustomMeta *) meta;
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|   GstMetaInfoImpl *info = (GstMetaInfoImpl *) meta->info;
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| 
 | |
|   if (info->custom_transform_func)
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|     return info->custom_transform_func (transbuf, cmeta,
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|         buffer, type, data, info->custom_transform_user_data);
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| 
 | |
|   if (GST_META_TRANSFORM_IS_COPY (type)) {
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|     custom = (GstCustomMeta *) gst_buffer_add_meta (transbuf, meta->info, NULL);
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|     gst_structure_set_parent_refcount (custom->structure, NULL);
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|     gst_structure_take (&custom->structure,
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|         gst_structure_copy (cmeta->structure));
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|     gst_structure_set_parent_refcount (custom->structure,
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|         &GST_MINI_OBJECT_REFCOUNT (transbuf));
 | |
|   } else {
 | |
|     return FALSE;
 | |
|   }
 | |
| 
 | |
|   return TRUE;
 | |
| }
 | |
| 
 | |
| static gboolean
 | |
| custom_serialize_func (const GstMeta * meta, GstByteArrayInterface * data,
 | |
|     guint8 * version)
 | |
| {
 | |
|   const GstCustomMeta *cmeta = (const GstCustomMeta *) meta;
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|   gchar *str = gst_structure_serialize_full (cmeta->structure,
 | |
|       GST_SERIALIZE_FLAG_STRICT);
 | |
|   if (str == NULL)
 | |
|     return FALSE;
 | |
| 
 | |
|   gboolean ret = gst_byte_array_interface_append_data (data, (guint8 *) str,
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|       strlen (str) + 1);
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|   g_free (str);
 | |
| 
 | |
|   return ret;
 | |
| }
 | |
| 
 | |
| static GstMeta *
 | |
| custom_deserialize_func (const GstMetaInfo * info, GstBuffer * buffer,
 | |
|     const guint8 * data, gsize size, guint8 version)
 | |
| {
 | |
|   if (version != 0 || size < 1 || data[size - 1] != '\0')
 | |
|     return NULL;
 | |
| 
 | |
|   GstStructure *structure =
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|       gst_structure_new_from_string ((const gchar *) data);
 | |
|   if (structure == NULL)
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|     return NULL;
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| 
 | |
|   GstMeta *meta = gst_buffer_add_meta (buffer, info, NULL);
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|   GstCustomMeta *cmeta = (GstCustomMeta *) meta;
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| 
 | |
|   gst_structure_set_parent_refcount (cmeta->structure, NULL);
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|   gst_structure_take (&cmeta->structure, structure);
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|   gst_structure_set_parent_refcount (cmeta->structure,
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|       &GST_MINI_OBJECT_REFCOUNT (buffer));
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| 
 | |
|   return meta;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_custom_meta_get_structure:
 | |
|  *
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|  * Retrieve the #GstStructure backing a custom meta, the structure's mutability
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|  * is conditioned to the writability of the #GstBuffer @meta is attached to.
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|  *
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|  * Returns: (transfer none): the #GstStructure backing @meta
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|  * Since: 1.20
 | |
|  */
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| GstStructure *
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| gst_custom_meta_get_structure (GstCustomMeta * meta)
 | |
| {
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|   g_return_val_if_fail (meta != NULL, NULL);
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|   g_return_val_if_fail (gst_meta_info_is_custom (((GstMeta *) meta)->info),
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|       NULL);
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| 
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|   return meta->structure;
 | |
| }
 | |
| 
 | |
| /**
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|  * gst_custom_meta_has_name:
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|  *
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|  * Checks whether the name of the custom meta is @name
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|  *
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|  * Returns: Whether @name is the name of the custom meta
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|  * Since: 1.20
 | |
|  */
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| gboolean
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| gst_custom_meta_has_name (GstCustomMeta * meta, const gchar * name)
 | |
| {
 | |
|   g_return_val_if_fail (meta != NULL, FALSE);
 | |
|   g_return_val_if_fail (gst_meta_info_is_custom (((GstMeta *) meta)->info),
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|       FALSE);
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| 
 | |
|   return gst_structure_has_name (meta->structure, name);
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_register_custom:
 | |
|  * @name: the name of the #GstMeta implementation
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|  * @tags: (array zero-terminated=1): tags for @api
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|  * @transform_func: (scope notified) (nullable): a #GstMetaTransformFunction
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|  * @user_data: (closure): user data passed to @transform_func
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|  * @destroy_data: #GDestroyNotify for user_data
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|  *
 | |
|  * Register a new custom #GstMeta implementation, backed by an opaque
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|  * structure holding a #GstStructure.
 | |
|  *
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|  * The registered info can be retrieved later with gst_meta_get_info() by using
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|  * @name as the key.
 | |
|  *
 | |
|  * The backing #GstStructure can be retrieved with
 | |
|  * gst_custom_meta_get_structure(), its mutability is conditioned by the
 | |
|  * writability of the buffer the meta is attached to.
 | |
|  *
 | |
|  * When @transform_func is %NULL, the meta and its backing #GstStructure
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|  * will always be copied when the transform operation is copy, other operations
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|  * are discarded, copy regions are ignored.
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|  *
 | |
|  * Returns: (transfer none): a #GstMetaInfo that can be used to
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|  * access metadata.
 | |
|  * Since: 1.20
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|  */
 | |
| const GstMetaInfo *
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| gst_meta_register_custom (const gchar * name, const gchar ** tags,
 | |
|     GstCustomMetaTransformFunction transform_func,
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|     gpointer user_data, GDestroyNotify destroy_data)
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| {
 | |
|   gchar *api_name = g_strdup_printf ("%s-api", name);
 | |
|   GType api;
 | |
|   GstMetaInfo *info;
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|   GstMetaInfoImpl *impl;
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|   const GstMetaInfo *ret = NULL;
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| 
 | |
|   g_return_val_if_fail (tags != NULL, NULL);
 | |
|   g_return_val_if_fail (name != NULL, NULL);
 | |
| 
 | |
|   api = gst_meta_api_type_register (api_name, tags);
 | |
|   g_free (api_name);
 | |
|   if (api == G_TYPE_INVALID)
 | |
|     goto done;
 | |
| 
 | |
|   info = gst_meta_info_new (api, name, sizeof (GstCustomMeta));
 | |
|   if (info == NULL)
 | |
|     goto done;
 | |
| 
 | |
|   impl = (GstMetaInfoImpl *) info;
 | |
| 
 | |
|   info->init_func = custom_init_func;
 | |
|   info->free_func = custom_free_func;
 | |
|   info->transform_func = custom_transform_func;
 | |
|   info->serialize_func = custom_serialize_func;
 | |
|   info->deserialize_func = custom_deserialize_func;
 | |
| 
 | |
|   impl->is_custom = TRUE;
 | |
|   impl->custom_transform_func = transform_func;
 | |
|   impl->custom_transform_user_data = user_data;
 | |
|   impl->custom_transform_destroy_notify = destroy_data;
 | |
| 
 | |
|   ret = gst_meta_info_register (info);
 | |
| 
 | |
| done:
 | |
|   return ret;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_register_custom_simple:
 | |
|  * @name: the name of the #GstMeta implementation
 | |
|  *
 | |
|  * Simplified version of gst_meta_register_custom(), with no tags and no
 | |
|  * transform function.
 | |
|  *
 | |
|  * Returns: (transfer none): a #GstMetaInfo that can be used to access metadata.
 | |
|  * Since: 1.24
 | |
|  */
 | |
| const GstMetaInfo *
 | |
| gst_meta_register_custom_simple (const gchar * name)
 | |
| {
 | |
|   const gchar *tags[] = { NULL };
 | |
|   return gst_meta_register_custom (name, tags, NULL, NULL, NULL);
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_info_is_custom:
 | |
|  *
 | |
|  * Returns: whether @info was registered as a #GstCustomMeta with
 | |
|  *   gst_meta_register_custom()
 | |
|  * Since:1.20
 | |
|  */
 | |
| gboolean
 | |
| gst_meta_info_is_custom (const GstMetaInfo * info)
 | |
| {
 | |
|   g_return_val_if_fail (info != NULL, FALSE);
 | |
| 
 | |
|   return ((GstMetaInfoImpl *) info)->is_custom;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_api_type_has_tag:
 | |
|  * @api: an API
 | |
|  * @tag: the tag to check
 | |
|  *
 | |
|  * Check if @api was registered with @tag.
 | |
|  *
 | |
|  * Returns: %TRUE if @api was registered with @tag.
 | |
|  */
 | |
| gboolean
 | |
| gst_meta_api_type_has_tag (GType api, GQuark tag)
 | |
| {
 | |
|   g_return_val_if_fail (api != 0, FALSE);
 | |
|   g_return_val_if_fail (tag != 0, FALSE);
 | |
| 
 | |
|   return g_type_get_qdata (api, tag) != NULL;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_api_type_get_tags:
 | |
|  * @api: an API
 | |
|  *
 | |
|  * Returns: (transfer none) (array zero-terminated=1) (element-type utf8): an array of tags as strings.
 | |
|  *
 | |
|  * Since: 1.2
 | |
|  */
 | |
| const gchar *const *
 | |
| gst_meta_api_type_get_tags (GType api)
 | |
| {
 | |
|   const gchar **tags;
 | |
|   g_return_val_if_fail (api != 0, FALSE);
 | |
| 
 | |
|   tags = g_type_get_qdata (api, GST_QUARK (TAGS));
 | |
| 
 | |
|   if (!tags[0])
 | |
|     return NULL;
 | |
| 
 | |
|   return (const gchar * const *) tags;
 | |
| }
 | |
| 
 | |
| static const GstMetaInfo *
 | |
| gst_meta_register_internal (GType api, const gchar * impl, gsize size,
 | |
|     GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
 | |
|     GstMetaTransformFunction transform_func,
 | |
|     GstMetaSerializeFunction serialize_func,
 | |
|     GstMetaDeserializeFunction deserialize_func)
 | |
| {
 | |
|   GstMetaInfo *info;
 | |
|   if (init_func == NULL)
 | |
|     g_critical ("Registering meta implementation '%s' without init function",
 | |
|         impl);
 | |
| 
 | |
|   info = gst_meta_info_new (api, impl, size);
 | |
|   if (info == NULL)
 | |
|     return NULL;
 | |
| 
 | |
|   info->init_func = init_func;
 | |
|   info->free_func = free_func;
 | |
|   info->transform_func = transform_func;
 | |
|   info->serialize_func = serialize_func;
 | |
|   info->deserialize_func = deserialize_func;
 | |
|   ((GstMetaInfoImpl *) info)->is_custom = FALSE;
 | |
| 
 | |
|   return gst_meta_info_register (info);
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_register: (skip):
 | |
|  * @api: the type of the #GstMeta API
 | |
|  * @impl: the name of the #GstMeta implementation
 | |
|  * @size: the size of the #GstMeta structure
 | |
|  * @init_func: a #GstMetaInitFunction
 | |
|  * @free_func: a #GstMetaFreeFunction
 | |
|  * @transform_func: a #GstMetaTransformFunction
 | |
|  *
 | |
|  * Register a new #GstMeta implementation.
 | |
|  *
 | |
|  * The same @info can be retrieved later with gst_meta_get_info() by using
 | |
|  * @impl as the key.
 | |
|  *
 | |
|  * Returns: (transfer none): a #GstMetaInfo that can be used to
 | |
|  * access metadata.
 | |
|  */
 | |
| const GstMetaInfo *
 | |
| gst_meta_register (GType api, const gchar * impl, gsize size,
 | |
|     GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
 | |
|     GstMetaTransformFunction transform_func)
 | |
| {
 | |
|   return gst_meta_register_internal (api, impl, size, init_func, free_func,
 | |
|       transform_func, NULL, NULL);
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_info_new: (skip):
 | |
|  * @api:  the type of the #GstMeta API
 | |
|  * @impl: the name of the #GstMeta implementation
 | |
|  * @size: the size of the #GstMeta structure
 | |
|  *
 | |
|  * Creates a new structure that needs to be filled before being
 | |
|  * registered.  This structure should filled and then registered with
 | |
|  * gst_meta_info_register().
 | |
|  *
 | |
|  * Example:
 | |
|  * ```c
 | |
|  * const GstMetaInfo *
 | |
|  * gst_my_meta_get_info (void)
 | |
|  * {
 | |
|  *   static const GstMetaInfo *meta_info = NULL;
 | |
|  *
 | |
|  *   if (g_once_init_enter ((GstMetaInfo **) & meta_info)) {
 | |
|  *     GstMetaInfo *info = gst_meta_info_new (
 | |
|  *       gst_my_meta_api_get_type (),
 | |
|  *         "GstMyMeta",
 | |
|  *        sizeof (GstMyMeta));
 | |
|  *     const GstMetaInfo *meta = NULL;
 | |
|  *
 | |
|  *     info->init_func = my_meta_init;
 | |
|  *     info->free_func = my_meta_free;
 | |
|  *     info->transform_func = my_meta_transform;
 | |
|  *     info->serialize_func = my_meta_serialize;
 | |
|  *     info->deserialize_func = my_meta_deserialize;
 | |
|  *     meta = gst_meta_info_register (info);
 | |
|  *     g_once_init_leave ((GstMetaInfo **) & meta_info, (GstMetaInfo *) meta);
 | |
|  *   }
 | |
|  *
 | |
|  *   return meta_info;
 | |
|  * }
 | |
|  * ```
 | |
|  *
 | |
|  * Returns: a new #GstMetaInfo that needs to be filled
 | |
|  *
 | |
|  * Since: 1.24
 | |
|  */
 | |
| 
 | |
| GstMetaInfo *
 | |
| gst_meta_info_new (GType api, const gchar * impl, gsize size)
 | |
| {
 | |
|   GType type;
 | |
|   GstMetaInfo *info;
 | |
| 
 | |
|   g_return_val_if_fail (api != 0, NULL);
 | |
|   g_return_val_if_fail (impl != NULL, NULL);
 | |
|   g_return_val_if_fail (size != 0, NULL);
 | |
| 
 | |
|   /* first try to register the implementation name. It's possible
 | |
|    * that this fails because it was already registered. Don't warn,
 | |
|    * glib did this for us already. */
 | |
|   type = g_pointer_type_register_static (impl);
 | |
| 
 | |
|   info = (GstMetaInfo *) g_new0 (GstMetaInfoImpl, 1);
 | |
|   info->api = api;
 | |
|   info->type = type;
 | |
|   info->size = size;
 | |
| 
 | |
|   return info;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_info_register:
 | |
|  * @info: (transfer full): a new #GstMetaInfo created by gst_meta_info_new()
 | |
|  *
 | |
|  * Registers a new meta.
 | |
|  *
 | |
|  * Use the structure returned by gst_meta_info_new(), it consumes it and the
 | |
|  * structure shouldnt be used after. The one returned by the function can be
 | |
|  * kept.
 | |
|  *
 | |
|  * Returns: (transfer none): the registered meta
 | |
|  *
 | |
|  * Since: 1.24
 | |
|  */
 | |
| 
 | |
| const GstMetaInfo *
 | |
| gst_meta_info_register (GstMetaInfo * info)
 | |
| {
 | |
|   if (info->type == G_TYPE_INVALID) {
 | |
|     g_free (info);
 | |
|     return NULL;
 | |
|   }
 | |
| 
 | |
|   GST_CAT_DEBUG (GST_CAT_META,
 | |
|       "register \"%s\" implementing \"%s\" of size %" G_GSIZE_FORMAT,
 | |
|       g_type_name (info->type), g_type_name (info->api), info->size);
 | |
| 
 | |
|   g_rw_lock_writer_lock (&lock);
 | |
|   g_hash_table_insert (metainfo,
 | |
|       (gpointer) g_intern_string (g_type_name (info->type)), (gpointer) info);
 | |
|   g_rw_lock_writer_unlock (&lock);
 | |
| 
 | |
|   return info;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_get_info:
 | |
|  * @impl: the name
 | |
|  *
 | |
|  * Lookup a previously registered meta info structure by its implementation name
 | |
|  * @impl.
 | |
|  *
 | |
|  * Returns: (transfer none) (nullable): a #GstMetaInfo with @impl, or
 | |
|  * %NULL when no such metainfo exists.
 | |
|  */
 | |
| const GstMetaInfo *
 | |
| gst_meta_get_info (const gchar * impl)
 | |
| {
 | |
|   GstMetaInfo *info;
 | |
| 
 | |
|   g_return_val_if_fail (impl != NULL, NULL);
 | |
| 
 | |
|   g_rw_lock_reader_lock (&lock);
 | |
|   info = g_hash_table_lookup (metainfo, impl);
 | |
|   g_rw_lock_reader_unlock (&lock);
 | |
| 
 | |
|   return info;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_get_seqnum:
 | |
|  * @meta: a #GstMeta
 | |
|  *
 | |
|  * Gets seqnum for this meta.
 | |
|  *
 | |
|  * Since: 1.16
 | |
|  */
 | |
| guint64
 | |
| gst_meta_get_seqnum (const GstMeta * meta)
 | |
| {
 | |
|   GstMetaItem *meta_item;
 | |
|   guint8 *p;
 | |
| 
 | |
|   g_return_val_if_fail (meta != NULL, 0);
 | |
| 
 | |
|   p = (guint8 *) meta;
 | |
|   p -= G_STRUCT_OFFSET (GstMetaItem, meta);
 | |
|   meta_item = (GstMetaItem *) p;
 | |
|   return meta_item->seq_num;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_compare_seqnum:
 | |
|  * @meta1: a #GstMeta
 | |
|  * @meta2: a #GstMeta
 | |
|  *
 | |
|  * Meta sequence number compare function. Can be used as #GCompareFunc
 | |
|  * or a #GCompareDataFunc.
 | |
|  *
 | |
|  * Returns: a negative number if @meta1 comes before @meta2, 0 if both metas
 | |
|  *   have an equal sequence number, or a positive integer if @meta1 comes
 | |
|  *   after @meta2.
 | |
|  *
 | |
|  * Since: 1.16
 | |
|  */
 | |
| gint
 | |
| gst_meta_compare_seqnum (const GstMeta * meta1, const GstMeta * meta2)
 | |
| {
 | |
|   guint64 seqnum1 = gst_meta_get_seqnum (meta1);
 | |
|   guint64 seqnum2 = gst_meta_get_seqnum (meta2);
 | |
| 
 | |
|   if (seqnum1 == seqnum2)
 | |
|     return 0;
 | |
| 
 | |
|   return (seqnum1 < seqnum2) ? -1 : 1;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_serialize:
 | |
|  * @meta: a #GstMeta
 | |
|  * @data: #GstByteArrayInterface to append serialization data
 | |
|  *
 | |
|  * Serialize @meta into a format that can be stored or transmitted and later
 | |
|  * deserialized by gst_meta_deserialize().
 | |
|  *
 | |
|  * This is only supported for meta that implements #GstMetaInfo.serialize_func,
 | |
|  * %FALSE is returned otherwise.
 | |
|  *
 | |
|  * Upon failure, @data->data pointer could have been reallocated, but @data->len
 | |
|  * won't be modified. This is intended to be able to append multiple metas
 | |
|  * into the same #GByteArray.
 | |
|  *
 | |
|  * Since serialization size is often the same for every buffer, caller may want
 | |
|  * to remember the size of previous data to preallocate the next.
 | |
|  *
 | |
|  * Returns: %TRUE on success, %FALSE otherwise.
 | |
|  *
 | |
|  * Since: 1.24
 | |
|  */
 | |
| gboolean
 | |
| gst_meta_serialize (const GstMeta * meta, GstByteArrayInterface * data)
 | |
| {
 | |
|   g_return_val_if_fail (meta != NULL, FALSE);
 | |
|   g_return_val_if_fail (data != NULL, FALSE);
 | |
| 
 | |
|   if (meta->info->serialize_func != NULL) {
 | |
|     const gchar *name = g_type_name (meta->info->type);
 | |
|     guint32 name_len = strlen (name);
 | |
|     guint32 orig_len = data->len;
 | |
|     guint8 version = 0;
 | |
| 
 | |
|     /* Format: [total size][name_len][name][\0][version][payload]
 | |
|      * Preallocate space for header but only write it on success because we
 | |
|      * don't have every info yet.
 | |
|      */
 | |
|     guint8 header_size = 2 * sizeof (guint32) + name_len + 2;
 | |
|     if (!gst_byte_array_interface_set_size (data, data->len + header_size))
 | |
|       return FALSE;
 | |
|     if (meta->info->serialize_func (meta, data, &version)) {
 | |
|       guint8 *header = data->data + orig_len;
 | |
|       GST_WRITE_UINT32_LE (header + 0, data->len - orig_len);
 | |
|       GST_WRITE_UINT32_LE (header + 4, name_len);
 | |
|       memcpy (header + 8, name, name_len + 1);
 | |
|       header[header_size - 1] = version;
 | |
|       return TRUE;
 | |
|     }
 | |
|     // Serialization failed, rollback.
 | |
|     gst_byte_array_interface_set_size (data, orig_len);
 | |
|   }
 | |
| 
 | |
|   return FALSE;
 | |
| }
 | |
| 
 | |
| typedef struct
 | |
| {
 | |
|   GstByteArrayInterface parent;
 | |
|   GByteArray *data;
 | |
| } ByteArrayImpl;
 | |
| 
 | |
| static gboolean
 | |
| byte_array_impl_resize (GstByteArrayInterface * parent, gsize length)
 | |
| {
 | |
|   ByteArrayImpl *self = (ByteArrayImpl *) parent;
 | |
| 
 | |
|   g_byte_array_set_size (self->data, length);
 | |
|   parent->data = self->data->data;
 | |
|   return TRUE;
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_serialize_simple:
 | |
|  * @meta: a #GstMeta
 | |
|  * @data: #GByteArray to append serialization data
 | |
|  *
 | |
|  * Same as gst_meta_serialize() but with a #GByteArray instead of
 | |
|  * #GstByteArrayInterface.
 | |
|  *
 | |
|  * Returns: %TRUE on success, %FALSE otherwise.
 | |
|  *
 | |
|  * Since: 1.24
 | |
|  */
 | |
| gboolean
 | |
| gst_meta_serialize_simple (const GstMeta * meta, GByteArray * data)
 | |
| {
 | |
|   ByteArrayImpl impl;
 | |
| 
 | |
|   gst_byte_array_interface_init (&impl.parent);
 | |
|   impl.parent.data = data->data;
 | |
|   impl.parent.len = data->len;
 | |
|   impl.parent.resize = byte_array_impl_resize;
 | |
|   impl.data = data;
 | |
|   return gst_meta_serialize (meta, (GstByteArrayInterface *) & impl);
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * gst_meta_deserialize:
 | |
|  * @buffer: a #GstBuffer
 | |
|  * @data: serialization data obtained from gst_meta_serialize()
 | |
|  * @size: size of @data
 | |
|  * @consumed: (out): total size used by this meta, could be less than @size
 | |
|  *
 | |
|  * Recreate a #GstMeta from serialized data returned by
 | |
|  * gst_meta_serialize() and add it to @buffer.
 | |
|  *
 | |
|  * Note that the meta must have been previously registered by calling one of
 | |
|  * `gst_*_meta_get_info ()` functions.
 | |
|  *
 | |
|  * @consumed is set to the number of bytes that can be skipped from @data to
 | |
|  * find the next meta serialization, if any. In case of parsing error that does
 | |
|  * not allow to determine that size, @consumed is set to 0.
 | |
|  *
 | |
|  * Returns: (transfer none) (nullable): the metadata owned by @buffer, or %NULL.
 | |
|  *
 | |
|  * Since: 1.24
 | |
|  */
 | |
| GstMeta *
 | |
| gst_meta_deserialize (GstBuffer * buffer, const guint8 * data, gsize size,
 | |
|     guint32 * consumed)
 | |
| {
 | |
|   g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
 | |
|   g_return_val_if_fail (data != NULL, NULL);
 | |
|   g_return_val_if_fail (consumed != NULL, NULL);
 | |
| 
 | |
|   *consumed = 0;
 | |
| 
 | |
|   /* Format: [total size][name_len][name][\0][version][payload] */
 | |
|   if (size < 2 * sizeof (guint32))
 | |
|     goto bad_header;
 | |
| 
 | |
|   guint32 total_size = GST_READ_UINT32_LE (data + 0);
 | |
|   guint32 name_len = GST_READ_UINT32_LE (data + 4);
 | |
|   guint32 header_size = 2 * sizeof (guint32) + name_len + 2;
 | |
|   if (size < total_size || total_size < header_size)
 | |
|     goto bad_header;
 | |
| 
 | |
|   guint8 version = data[header_size - 1];
 | |
|   const gchar *name = (const gchar *) (data + 2 * sizeof (guint32));
 | |
|   if (name[name_len] != '\0')
 | |
|     goto bad_header;
 | |
| 
 | |
|   *consumed = total_size;
 | |
| 
 | |
|   const GstMetaInfo *info = gst_meta_get_info (name);
 | |
|   if (info == NULL) {
 | |
|     GST_CAT_WARNING (GST_CAT_META,
 | |
|         "%s does not correspond to a registered meta", name);
 | |
|     return NULL;
 | |
|   }
 | |
| 
 | |
|   if (info->deserialize_func == NULL) {
 | |
|     GST_CAT_WARNING (GST_CAT_META, "Meta %s does not support deserialization",
 | |
|         name);
 | |
|     return NULL;
 | |
|   }
 | |
| 
 | |
|   const guint8 *payload = data + header_size;
 | |
|   guint32 payload_size = total_size - header_size;
 | |
|   GstMeta *meta =
 | |
|       info->deserialize_func (info, buffer, payload, payload_size, version);
 | |
|   if (meta == NULL) {
 | |
|     GST_CAT_WARNING (GST_CAT_META, "Failed to deserialize %s payload", name);
 | |
|     GST_CAT_MEMDUMP (GST_CAT_META, "Meta serialization payload", payload,
 | |
|         payload_size);
 | |
|     return NULL;
 | |
|   }
 | |
| 
 | |
|   return meta;
 | |
| 
 | |
| bad_header:
 | |
|   GST_CAT_WARNING (GST_CAT_META, "Could not parse meta serialization header");
 | |
|   GST_CAT_MEMDUMP (GST_CAT_META, "Meta serialization data", data, size);
 | |
|   return NULL;
 | |
| }
 |