gstreamer/gst/gstmeta.c

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/* GStreamer
* Copyright (C) 2011 Wim Taymans <wim.taymans@gmail.com>
*
* gstmeta.c: metadata operations
*
* 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:gstmeta
* @short_description: Buffer metadata
*
* Last reviewed on December 17th, 2009 (0.10.26)
*/
#include "gst_private.h"
#include "gstbuffer.h"
#include "gstmeta.h"
#include "gstinfo.h"
#include "gstutils.h"
static GHashTable *metainfo = NULL;
static GStaticRWLock lock = G_STATIC_RW_LOCK_INIT;
void
_gst_meta_init (void)
{
metainfo = g_hash_table_new (g_str_hash, g_str_equal);
}
/**
* gst_meta_register_info:
* @info: a #GstMetaInfo
*
* Register a #GstMetaInfo. The same @info can be retrieved later with
* gst_meta_get_info() by using @impl as the key.
*
* Returns: a #GstMetaInfo that can be used to access metadata.
*/
const GstMetaInfo *
gst_meta_register (const gchar * api, const gchar * impl, gsize size,
GstMetaInitFunction init_func, GstMetaFreeFunction free_func,
GstMetaCopyFunction copy_func, GstMetaSubFunction sub_func,
GstMetaSerializeFunction serialize_func,
GstMetaDeserializeFunction deserialize_func)
{
GstMetaInfo *info;
g_return_val_if_fail (api != NULL, NULL);
g_return_val_if_fail (impl != NULL, NULL);
g_return_val_if_fail (size != 0, NULL);
info = g_slice_new (GstMetaInfo);
info->api = g_quark_from_string (api);
info->impl = g_quark_from_string (impl);
info->size = size;
info->init_func = init_func;
info->free_func = free_func;
info->copy_func = copy_func;
info->sub_func = sub_func;
info->serialize_func = serialize_func;
info->deserialize_func = deserialize_func;
GST_DEBUG ("register \"%s\" implementing \"%s\" of size %" G_GSIZE_FORMAT,
api, impl, size);
g_static_rw_lock_writer_lock (&lock);
g_hash_table_insert (metainfo, (gpointer) impl, (gpointer) info);
g_static_rw_lock_writer_unlock (&lock);
return info;
}
/**
* gst_meta_get_info:
* @name: the name
*
* Lookup a previously registered meta info structure by its @implementor name.
*
* Returns: a #GstMetaInfo with @name 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_static_rw_lock_reader_lock (&lock);
info = g_hash_table_lookup (metainfo, impl);
g_static_rw_lock_reader_unlock (&lock);
return info;
}
typedef struct
{
guint8 *data;
GFreeFunc free_func;
gsize size;
gsize offset;
} GstMetaMemoryParams;
typedef struct
{
GstMetaMemory memory;
GstMetaMemoryParams params;
} GstMetaMemoryImpl;
static gpointer
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meta_memory_mmap (GstMetaMemory * meta, gsize offset, gsize * size,
GstMetaMapFlags flags)
{
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GstMetaMemoryImpl *impl = (GstMetaMemoryImpl *) meta;
*size = impl->params.size - offset;
return impl->params.data + offset;
}
static gboolean
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meta_memory_munmap (GstMetaMemory * meta, gpointer data, gsize size)
{
return TRUE;
}
static gboolean
meta_memory_init (GstMetaMemoryImpl * meta, GstMetaMemoryParams * params,
GstBuffer * buffer)
{
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meta->memory.mmap_func = meta_memory_mmap;
meta->memory.munmap_func = meta_memory_munmap;
meta->params = *params;
return TRUE;
}
static void
meta_memory_free (GstMetaMemoryImpl * meta, GstBuffer * buffer)
{
if (meta->params.free_func)
meta->params.free_func (meta->params.data);
}
static void
meta_memory_copy (GstBuffer * copy, GstMetaMemoryImpl * meta,
const GstBuffer * buffer)
{
gst_buffer_add_meta_memory (copy,
g_memdup (meta->params.data, meta->params.size),
g_free, meta->params.size, meta->params.offset);
}
static void
meta_memory_sub (GstBuffer * subbuf, GstMetaMemoryImpl * meta,
GstBuffer * buffer, guint offset, guint size)
{
gst_buffer_add_meta_memory (subbuf,
meta->params.data, NULL, size, meta->params.offset + offset);
}
const GstMetaInfo *
gst_meta_memory_get_info (void)
{
static const GstMetaInfo *meta_info = NULL;
if (meta_info == NULL) {
meta_info = gst_meta_register ("GstMetaMemory", "GstMetaMemoryImpl",
sizeof (GstMetaMemoryImpl),
(GstMetaInitFunction) meta_memory_init,
(GstMetaFreeFunction) meta_memory_free,
(GstMetaCopyFunction) meta_memory_copy,
(GstMetaSubFunction) meta_memory_sub,
(GstMetaSerializeFunction) NULL, (GstMetaDeserializeFunction) NULL);
}
return meta_info;
}
GstMetaMemory *
gst_buffer_add_meta_memory (GstBuffer * buffer, gpointer data,
GFreeFunc free_func, gsize size, gsize offset)
{
GstMeta *meta;
GstMetaMemoryParams params;
params.data = data;
params.free_func = free_func;
params.size = size;
params.offset = offset;
meta = gst_buffer_add_meta (buffer, GST_META_MEMORY_INFO, &params);
return (GstMetaMemory *) meta;
}