/* GStreamer

 * Copyright (C) 2009 Wim Taymans <wim.taymans@gmail.be>

 *

 * gstmeta.h: Header for Metadata structures

 *

 * 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.

 */

#ifndef __GST_META_H__

#define __GST_META_H__

#include <glib.h>

G_BEGIN_DECLS

typedef struct _GstMeta GstMeta;

typedef struct _GstMetaInfo GstMetaInfo;

#define GST_META_CAST(meta)   ((GstMeta *)(meta))

/**

 * GstMetaFlags:

 * @GST_META_FLAG_NONE: no flags

 * @GST_META_FLAG_READONLY: metadata should not be modified

 * @GST_META_FLAG_POOLED: metadata is managed by a bufferpool

 * @GST_META_FLAG_LOCKED: metadata should not be removed

 * @GST_META_FLAG_LAST: additional flags can be added starting from this flag.

 *

 * Extra metadata flags.

 */

typedef enum {

  GST_META_FLAG_NONE        = 0,

  GST_META_FLAG_READONLY    = (1 << 0),

  GST_META_FLAG_POOLED      = (1 << 1),

  GST_META_FLAG_LOCKED      = (1 << 2),

  GST_META_FLAG_LAST        = (1 << 16)

} GstMetaFlags;

/**

 * GST_META_FLAGS:

 * @meta: a #GstMeta.

 *

 * A flags word containing #GstMetaFlags flags set on @meta

 */

#define GST_META_FLAGS(meta)  (GST_META_CAST (meta)->flags)

/**

 * GST_META_FLAG_IS_SET:

 * @meta: a #GstMeta.

 * @flag: the #GstMetaFlags to check.

 *

 * Gives the status of a specific flag on a metadata.

 */

#define GST_META_FLAG_IS_SET(meta,flag)        !!(GST_META_FLAGS (meta) & (flag))

/**

 * GST_META_FLAG_SET:

 * @meta: a #GstMeta.

 * @flag: the #GstMetaFlags to set.

 *

 * Sets a metadata flag on a metadata.

 */

#define GST_META_FLAG_SET(meta,flag)           (GST_META_FLAGS (meta) |= (flag))

/**

 * GST_META_FLAG_UNSET:

 * @meta: a #GstMeta.

 * @flag: the #GstMetaFlags to clear.

 *

 * Clears a metadata flag.

 */

#define GST_META_FLAG_UNSET(meta,flag)         (GST_META_FLAGS (meta) &= ~(flag))

/**

 * GST_META_TAG_MEMORY_STR:

 *

 * This metadata stays relevant as long as memory layout is unchanged.

 *

 * Since: 1.2

 */

#define GST_META_TAG_MEMORY_STR "memory"

/**

 * GstMeta:

 * @flags: extra flags for the metadata

 * @info: pointer to the #GstMetaInfo

 *

 * Base structure for metadata. Custom metadata will put this structure

 * as the first member of their structure.

 */

struct _GstMeta {

  GstMetaFlags       flags;

  const GstMetaInfo *info;

};

#include <gst/gstbuffer.h>

/**

 * GstMetaInitFunction:

 * @meta: a #GstMeta

 * @params: parameters passed to the init function

 * @buffer: a #GstBuffer

 *

 * Function called when @meta is initialized in @buffer.

 */

typedef gboolean (*GstMetaInitFunction) (GstMeta *meta, gpointer params, GstBuffer *buffer);

/**

 * GstMetaFreeFunction:

 * @meta: a #GstMeta

 * @buffer: a #GstBuffer

 *

 * Function called when @meta is freed in @buffer.

 */

typedef void (*GstMetaFreeFunction)     (GstMeta *meta, GstBuffer *buffer);

/**

 * gst_meta_transform_copy:

 *

 * GQuark for the "gst-copy" transform.

 */

GST_API GQuark _gst_meta_transform_copy;

/**

 * GST_META_TRANSFORM_IS_COPY:

 * @type: a transform type

 *

 * Check if the transform type is a copy transform

 */

#define GST_META_TRANSFORM_IS_COPY(type) ((type) == _gst_meta_transform_copy)

/**

 * GstMetaTransformCopy:

 * @region: %TRUE if only region is copied

 * @offset: the offset to copy, 0 if @region is %FALSE, otherwise > 0

 * @size: the size to copy, -1 or the buffer size when @region is %FALSE

 *

 * Extra data passed to a "gst-copy" transform #GstMetaTransformFunction.

 */

typedef struct {

  gboolean region;

  gsize offset;

  gsize size;

} GstMetaTransformCopy;

/**

 * GstMetaTransformFunction:

 * @transbuf: a #GstBuffer

 * @meta: a #GstMeta

 * @buffer: a #GstBuffer

 * @type: the transform type

 * @data: transform specific data.

 *

 * Function called for each @meta in @buffer as a result of performing a

 * transformation on @transbuf. Additional @type specific transform data

 * is passed to the function as @data.

 *

 * Implementations should check the @type of the transform and parse

 * additional type specific fields in @data that should be used to update

 * the metadata on @transbuf.

 *

 * Returns: %TRUE if the transform could be performed

 */

typedef gboolean (*GstMetaTransformFunction) (GstBuffer *transbuf,

                                              GstMeta *meta, GstBuffer *buffer,

                                              GQuark type, gpointer data);

/**

 * GstMetaInfo:

 * @api: tag identifying the metadata structure and api

 * @type: type identifying the implementor of the api

 * @size: size of the metadata

 * @init_func: function for initializing the metadata

 * @free_func: function for freeing the metadata

 * @transform_func: function for transforming the metadata

 *

 * The #GstMetaInfo provides information about a specific metadata

 * structure.

 */

struct _GstMetaInfo {

  GType                      api;

  GType                      type;

  gsize                      size;

  GstMetaInitFunction        init_func;

  GstMetaFreeFunction        free_func;

  GstMetaTransformFunction   transform_func;

  /* No padding needed, GstMetaInfo is always allocated by GStreamer and is

   * not subclassable or stack-allocatable, so we can extend it as we please

   * just like interfaces */

};

GST_API

GType                gst_meta_api_type_register (const gchar *api,

                                                 const gchar **tags);

GST_API

gboolean             gst_meta_api_type_has_tag  (GType api, GQuark tag);

GST_API

const GstMetaInfo *  gst_meta_register          (GType api, const gchar *impl,

                                                 gsize size,

                                                 GstMetaInitFunction      init_func,

                                                 GstMetaFreeFunction      free_func,

                                                 GstMetaTransformFunction transform_func);

GST_API

const GstMetaInfo *  gst_meta_get_info          (const gchar * impl);

GST_API

const gchar* const*  gst_meta_api_type_get_tags (GType api);

/* some default tags */

GST_API GQuark _gst_meta_tag_memory;

/**

 * GST_META_TAG_MEMORY:

 *

 * Metadata tagged with this tag depends on the particular memory

 * or buffer that it is on.

 *

 * Deprecated: The GQuarks are not exported by any public API, use

 *   GST_META_TAG_MEMORY_STR instead.

 */

#ifndef GST_DISABLE_DEPRECATED

#define GST_META_TAG_MEMORY (_gst_meta_tag_memory)

#endif

G_END_DECLS

#endif /* __GST_META_H__ */