/* GStreamer

 * Copyright (C) 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>

 *

 * gsttaglist.c: tag support (aka metadata)

 *

 * 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:gsttaglist

 * @title: GstTagList

 * @short_description: List of tags and values used to describe media metadata

 *

 * List of tags and values used to describe media metadata.

 *

 * Strings in structures must be ASCII or UTF-8 encoded. Other encodings are

 * not allowed. Strings must not be empty or %NULL.

 */

#ifdef HAVE_CONFIG_H

#  include "config.h"

#endif

#include "gst_private.h"

#include "math-compat.h"

#include "gst-i18n-lib.h"

#include "gsttaglist.h"

#include "gstinfo.h"

#include "gstvalue.h"

#include "gstbuffer.h"

#include "gstquark.h"

#include "gststructure.h"

#include <gobject/gvaluecollector.h>

#include <string.h>

/* FIXME: add category for tags */

#define GST_CAT_TAGS GST_CAT_DEFAULT

#define GST_TAG_IS_VALID(tag)           (gst_tag_get_info (tag) != NULL)

typedef struct _GstTagListImpl

{

  GstTagList taglist;

  GstStructure *structure;

  GstTagScope scope;

} GstTagListImpl;

#define GST_TAG_LIST_STRUCTURE(taglist)  ((GstTagListImpl*)(taglist))->structure

#define GST_TAG_LIST_SCOPE(taglist)  ((GstTagListImpl*)(taglist))->scope

typedef struct

{

  GType type;                   /* type the data is in */

  const gchar *nick;            /* translated short description */

  const gchar *blurb;           /* translated long description  */

  GstTagMergeFunc merge_func;   /* functions to merge the values */

  GstTagFlag flag;              /* type of tag */

  GQuark name_quark;            /* quark for the name */

}

GstTagInfo;

#define g_value_get_char g_value_get_schar

static GMutex __tag_mutex;

#define TAG_LOCK g_mutex_lock (&__tag_mutex)

#define TAG_UNLOCK g_mutex_unlock (&__tag_mutex)

/* tags hash table: maps tag name string => GstTagInfo */

static GHashTable *__tags;

GType _gst_tag_list_type = 0;

GST_DEFINE_MINI_OBJECT_TYPE (GstTagList, gst_tag_list);

static void __gst_tag_list_free (GstTagList * list);

static GstTagList *__gst_tag_list_copy (const GstTagList * list);

/* FIXME: had code:

 *    g_value_register_transform_func (_gst_tag_list_type, G_TYPE_STRING,

 *      _gst_structure_transform_to_string);

 */

void

_priv_gst_tag_initialize (void)

{

  g_mutex_init (&__tag_mutex);

  _gst_tag_list_type = gst_tag_list_get_type ();

  __tags = g_hash_table_new (g_str_hash, g_str_equal);

  gst_tag_register_static (GST_TAG_TITLE, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("title"), _("commonly used title"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_TITLE_SORTNAME, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("title sortname"), _("commonly used title for sorting purposes"), NULL);

  gst_tag_register_static (GST_TAG_ARTIST, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("artist"),

      _("person(s) responsible for the recording"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_ARTIST_SORTNAME, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("artist sortname"),

      _("person(s) responsible for the recording for sorting purposes"), NULL);

  gst_tag_register_static (GST_TAG_ALBUM, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("album"),

      _("album containing this data"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_ALBUM_SORTNAME, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("album sortname"),

      _("album containing this data for sorting purposes"), NULL);

  gst_tag_register_static (GST_TAG_ALBUM_ARTIST, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("album artist"),

      _("The artist of the entire album, as it should be displayed"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_ALBUM_ARTIST_SORTNAME, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("album artist sortname"),

      _("The artist of the entire album, as it should be sorted"), NULL);

  gst_tag_register_static (GST_TAG_DATE, GST_TAG_FLAG_META, G_TYPE_DATE,

      _("date"), _("date the data was created (as a GDate structure)"), NULL);

  gst_tag_register_static (GST_TAG_DATE_TIME, GST_TAG_FLAG_META,

      GST_TYPE_DATE_TIME, _("datetime"),

      _("date and time the data was created (as a GstDateTime structure)"),

      NULL);

  gst_tag_register_static (GST_TAG_GENRE, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("genre"),

      _("genre this data belongs to"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_COMMENT, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("comment"),

      _("free text commenting the data"), gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_EXTENDED_COMMENT, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("extended comment"),

      _("free text commenting the data in key=value or key[en]=comment form"),

      gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_TRACK_NUMBER, GST_TAG_FLAG_META,

      G_TYPE_UINT,

      _("track number"),

      _("track number inside a collection"), gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_TRACK_COUNT, GST_TAG_FLAG_META,

      G_TYPE_UINT,

      _("track count"),

      _("count of tracks inside collection this track belongs to"),

      gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_ALBUM_VOLUME_NUMBER, GST_TAG_FLAG_META,

      G_TYPE_UINT,

      _("disc number"),

      _("disc number inside a collection"), gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_ALBUM_VOLUME_COUNT, GST_TAG_FLAG_META,

      G_TYPE_UINT,

      _("disc count"),

      _("count of discs inside collection this disc belongs to"),

      gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_LOCATION, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("location"), _("Origin of media as a URI (location, where the "

          "original of the file or stream is hosted)"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_HOMEPAGE, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("homepage"),

      _("Homepage for this media (i.e. artist or movie homepage)"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_DESCRIPTION, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("description"),

      _("short text describing the content of the data"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_VERSION, GST_TAG_FLAG_META, G_TYPE_STRING,

      _("version"), _("version of this data"), NULL);

  gst_tag_register_static (GST_TAG_ISRC, GST_TAG_FLAG_META, G_TYPE_STRING,

      _("ISRC"),

      _

      ("International Standard Recording Code - see http://www.ifpi.org/isrc/"),

      NULL);

  /* FIXME: organization (fix what? tpm) */

  gst_tag_register_static (GST_TAG_ORGANIZATION, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("organization"), _("organization"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_COPYRIGHT, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("copyright"), _("copyright notice of the data"), NULL);

  gst_tag_register_static (GST_TAG_COPYRIGHT_URI, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("copyright uri"),

      _("URI to the copyright notice of the data"), NULL);

  gst_tag_register_static (GST_TAG_ENCODED_BY, GST_TAG_FLAG_META, G_TYPE_STRING,

      _("encoded by"), _("name of the encoding person or organization"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_CONTACT, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("contact"), _("contact information"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_LICENSE, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("license"), _("license of data"), NULL);

  gst_tag_register_static (GST_TAG_LICENSE_URI, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("license uri"),

      _("URI to the license of the data"), NULL);

  gst_tag_register_static (GST_TAG_PERFORMER, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("performer"),

      _("person(s) performing"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_COMPOSER, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("composer"),

      _("person(s) who composed the recording"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_CONDUCTOR, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("conductor"),

      _("conductor/performer refinement"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_DURATION, GST_TAG_FLAG_DECODED,

      G_TYPE_UINT64,

      _("duration"), _("length in GStreamer time units (nanoseconds)"), NULL);

  gst_tag_register_static (GST_TAG_CODEC, GST_TAG_FLAG_ENCODED,

      G_TYPE_STRING,

      _("codec"),

      _("codec the data is stored in"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_VIDEO_CODEC, GST_TAG_FLAG_ENCODED,

      G_TYPE_STRING,

      _("video codec"), _("codec the video data is stored in"), NULL);

  gst_tag_register_static (GST_TAG_AUDIO_CODEC, GST_TAG_FLAG_ENCODED,

      G_TYPE_STRING,

      _("audio codec"), _("codec the audio data is stored in"), NULL);

  gst_tag_register_static (GST_TAG_SUBTITLE_CODEC, GST_TAG_FLAG_ENCODED,

      G_TYPE_STRING,

      _("subtitle codec"), _("codec the subtitle data is stored in"), NULL);

  gst_tag_register_static (GST_TAG_CONTAINER_FORMAT, GST_TAG_FLAG_ENCODED,

      G_TYPE_STRING, _("container format"),

      _("container format the data is stored in"), NULL);

  gst_tag_register_static (GST_TAG_BITRATE, GST_TAG_FLAG_ENCODED,

      G_TYPE_UINT, _("bitrate"), _("exact or average bitrate in bits/s"), NULL);

  gst_tag_register_static (GST_TAG_NOMINAL_BITRATE, GST_TAG_FLAG_ENCODED,

      G_TYPE_UINT, _("nominal bitrate"), _("nominal bitrate in bits/s"), NULL);

  gst_tag_register_static (GST_TAG_MINIMUM_BITRATE, GST_TAG_FLAG_ENCODED,

      G_TYPE_UINT, _("minimum bitrate"), _("minimum bitrate in bits/s"), NULL);

  gst_tag_register_static (GST_TAG_MAXIMUM_BITRATE, GST_TAG_FLAG_ENCODED,

      G_TYPE_UINT, _("maximum bitrate"), _("maximum bitrate in bits/s"), NULL);

  gst_tag_register_static (GST_TAG_ENCODER, GST_TAG_FLAG_ENCODED,

      G_TYPE_STRING,

      _("encoder"), _("encoder used to encode this stream"), NULL);

  gst_tag_register_static (GST_TAG_ENCODER_VERSION, GST_TAG_FLAG_ENCODED,

      G_TYPE_UINT,

      _("encoder version"),

      _("version of the encoder used to encode this stream"), NULL);

  gst_tag_register_static (GST_TAG_SERIAL, GST_TAG_FLAG_ENCODED,

      G_TYPE_UINT, _("serial"), _("serial number of track"), NULL);

  gst_tag_register_static (GST_TAG_TRACK_GAIN, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("replaygain track gain"), _("track gain in db"), NULL);

  gst_tag_register_static (GST_TAG_TRACK_PEAK, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("replaygain track peak"), _("peak of the track"), NULL);

  gst_tag_register_static (GST_TAG_ALBUM_GAIN, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("replaygain album gain"), _("album gain in db"), NULL);

  gst_tag_register_static (GST_TAG_ALBUM_PEAK, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("replaygain album peak"), _("peak of the album"), NULL);

  gst_tag_register_static (GST_TAG_REFERENCE_LEVEL, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("replaygain reference level"),

      _("reference level of track and album gain values"), NULL);

  gst_tag_register_static (GST_TAG_LANGUAGE_CODE, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("language code"),

      _("language code for this stream, conforming to ISO-639-1 or ISO-639-2"),

      NULL);

  gst_tag_register_static (GST_TAG_LANGUAGE_NAME, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("language name"),

      _("freeform name of the language this stream is in"), NULL);

  gst_tag_register_static (GST_TAG_IMAGE, GST_TAG_FLAG_META, GST_TYPE_SAMPLE,

      _("image"), _("image related to this stream"), gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_PREVIEW_IMAGE, GST_TAG_FLAG_META,

      GST_TYPE_SAMPLE,

      /* TRANSLATORS: 'preview image' = image that shows a preview of the full image */

      _("preview image"), _("preview image related to this stream"), NULL);

  gst_tag_register_static (GST_TAG_ATTACHMENT, GST_TAG_FLAG_META,

      GST_TYPE_SAMPLE, _("attachment"), _("file attached to this stream"),

      gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_BEATS_PER_MINUTE, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("beats per minute"),

      _("number of beats per minute in audio"), NULL);

  gst_tag_register_static (GST_TAG_KEYWORDS, GST_TAG_FLAG_META, G_TYPE_STRING,

      _("keywords"), _("comma separated keywords describing the content"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_NAME, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("geo location name"),

      _("human readable descriptive location of where "

          "the media has been recorded or produced"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_LATITUDE, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("geo location latitude"),

      _("geo latitude location of where the media has been recorded or "

          "produced in degrees according to WGS84 (zero at the equator, "

          "negative values for southern latitudes)"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_LONGITUDE, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("geo location longitude"),

      _("geo longitude location of where the media has been recorded or "

          "produced in degrees according to WGS84 (zero at the prime meridian "

          "in Greenwich/UK,  negative values for western longitudes)"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_ELEVATION, GST_TAG_FLAG_META,

      G_TYPE_DOUBLE, _("geo location elevation"),

      _("geo elevation of where the media has been recorded or produced in "

          "meters according to WGS84 (zero is average sea level)"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_COUNTRY, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("geo location country"),

      _("country (english name) where the media has been recorded "

          "or produced"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_CITY, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("geo location city"),

      _("city (english name) where the media has been recorded "

          "or produced"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_SUBLOCATION, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("geo location sublocation"),

      _("a location within a city where the media has been produced "

          "or created (e.g. the neighborhood)"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_HORIZONTAL_ERROR,

      GST_TAG_FLAG_META, G_TYPE_DOUBLE, _("geo location horizontal error"),

      _("expected error of the horizontal positioning measures (in meters)"),

      NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_MOVEMENT_SPEED,

      GST_TAG_FLAG_META, G_TYPE_DOUBLE, _("geo location movement speed"),

      _("movement speed of the capturing device while performing the capture "

          "in m/s"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION,

      GST_TAG_FLAG_META, G_TYPE_DOUBLE, _("geo location movement direction"),

      _("indicates the movement direction of the device performing the capture"

          " of a media. It is represented as degrees in floating point "

          "representation, 0 means the geographic north, and increases "

          "clockwise"), NULL);

  gst_tag_register_static (GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION,

      GST_TAG_FLAG_META, G_TYPE_DOUBLE, _("geo location capture direction"),

      _("indicates the direction the device is pointing to when capturing "

          " a media. It is represented as degrees in floating point "

          " representation, 0 means the geographic north, and increases "

          "clockwise"), NULL);

  gst_tag_register_static (GST_TAG_SHOW_NAME, GST_TAG_FLAG_META, G_TYPE_STRING,

      /* TRANSLATORS: 'show name' = 'TV/radio/podcast show name' here */

      _("show name"),

      _("Name of the tv/podcast/series show the media is from"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_SHOW_SORTNAME, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      /* TRANSLATORS: 'show sortname' = 'TV/radio/podcast show name as used for sorting purposes' here */

      _("show sortname"),

      _("Name of the tv/podcast/series show the media is from, for sorting "

          "purposes"), NULL);

  gst_tag_register_static (GST_TAG_SHOW_EPISODE_NUMBER, GST_TAG_FLAG_META,

      G_TYPE_UINT, _("episode number"),

      _("The episode number in the season the media is part of"),

      gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_SHOW_SEASON_NUMBER, GST_TAG_FLAG_META,

      G_TYPE_UINT, _("season number"),

      _("The season number of the show the media is part of"),

      gst_tag_merge_use_first);

  gst_tag_register_static (GST_TAG_LYRICS, GST_TAG_FLAG_META, G_TYPE_STRING,

      _("lyrics"), _("The lyrics of the media, commonly used for songs"),

      gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_COMPOSER_SORTNAME, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("composer sortname"),

      _("person(s) who composed the recording, for sorting purposes"), NULL);

  gst_tag_register_static (GST_TAG_GROUPING, GST_TAG_FLAG_META, G_TYPE_STRING,

      _("grouping"),

      _("Groups related media that spans multiple tracks, like the different "

          "pieces of a concerto. It is a higher level than a track, "

          "but lower than an album"), NULL);

  gst_tag_register_static (GST_TAG_USER_RATING, GST_TAG_FLAG_META, G_TYPE_UINT,

      _("user rating"),

      _("Rating attributed by a user. The higher the rank, "

          "the more the user likes this media"), NULL);

  gst_tag_register_static (GST_TAG_DEVICE_MANUFACTURER, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("device manufacturer"),

      _("Manufacturer of the device used to create this media"), NULL);

  gst_tag_register_static (GST_TAG_DEVICE_MODEL, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("device model"),

      _("Model of the device used to create this media"), NULL);

  gst_tag_register_static (GST_TAG_APPLICATION_NAME, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("application name"),

      _("Application used to create the media"), NULL);

  gst_tag_register_static (GST_TAG_APPLICATION_DATA, GST_TAG_FLAG_META,

      GST_TYPE_SAMPLE, _("application data"),

      _("Arbitrary application data to be serialized into the media"), NULL);

  gst_tag_register_static (GST_TAG_IMAGE_ORIENTATION, GST_TAG_FLAG_META,

      G_TYPE_STRING, _("image orientation"),

      _("How the image should be rotated or flipped before display"), NULL);

  gst_tag_register_static (GST_TAG_PUBLISHER, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("publisher"),

      _("Name of the label or publisher"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_INTERPRETED_BY, GST_TAG_FLAG_META,

      G_TYPE_STRING,

      _("interpreted-by"),

      _("Information about the people behind a remix and similar "

          "interpretations"), gst_tag_merge_strings_with_comma);

  gst_tag_register_static (GST_TAG_MIDI_BASE_NOTE, GST_TAG_FLAG_META,

      G_TYPE_UINT,

      _("midi-base-note"), _("Midi note number of the audio track."), NULL);

  gst_tag_register_static (GST_TAG_PRIVATE_DATA, GST_TAG_FLAG_META,

      GST_TYPE_SAMPLE,

      _("private-data"), _("Private data"), gst_tag_merge_use_first);

}

/**

 * gst_tag_merge_use_first:

 * @dest: (out caller-allocates): uninitialized GValue to store result in

 * @src: GValue to copy from

 *

 * This is a convenience function for the func argument of gst_tag_register().

 * It creates a copy of the first value from the list.

 */

void

gst_tag_merge_use_first (GValue * dest, const GValue * src)

{

  const GValue *ret = gst_value_list_get_value (src, 0);

  g_value_init (dest, G_VALUE_TYPE (ret));

  g_value_copy (ret, dest);

}

/**

 * gst_tag_merge_strings_with_comma:

 * @dest: (out caller-allocates): uninitialized GValue to store result in

 * @src: GValue to copy from

 *

 * This is a convenience function for the func argument of gst_tag_register().

 * It concatenates all given strings using a comma. The tag must be registered

 * as a G_TYPE_STRING or this function will fail.

 */

void

gst_tag_merge_strings_with_comma (GValue * dest, const GValue * src)

{

  GString *str;

  gint i, count;

  count = gst_value_list_get_size (src);

  str = g_string_new (g_value_get_string (gst_value_list_get_value (src, 0)));

  for (i = 1; i < count; i++) {

    /* separator between two strings */

    g_string_append (str, _(", "));

    g_string_append (str,

        g_value_get_string (gst_value_list_get_value (src, i)));

  }

  g_value_init (dest, G_TYPE_STRING);

  g_value_take_string (dest, str->str);

  g_string_free (str, FALSE);

}

static GstTagInfo *

gst_tag_lookup (const gchar * tag_name)

{

  GstTagInfo *ret;

  TAG_LOCK;

  ret = g_hash_table_lookup (__tags, (gpointer) tag_name);

  TAG_UNLOCK;

  return ret;

}

/**

 * gst_tag_register:

 * @name: the name or identifier string

 * @flag: a flag describing the type of tag info

 * @type: the type this data is in

 * @nick: human-readable name

 * @blurb: a human-readable description about this tag

 * @func: (allow-none) (scope call): function for merging multiple values of this tag, or %NULL

 *

 * Registers a new tag type for the use with GStreamer's type system. If a type

 * with that name is already registered, that one is used.

 * The old registration may have used a different type however. So don't rely

 * on your supplied values.

 *

 * Important: if you do not supply a merge function the implication will be

 * that there can only be one single value for this tag in a tag list and

 * any additional values will silently be discarded when being added (unless

 * #GST_TAG_MERGE_REPLACE, #GST_TAG_MERGE_REPLACE_ALL, or

 * #GST_TAG_MERGE_PREPEND is used as merge mode, in which case the new

 * value will replace the old one in the list).

 *

 * The merge function will be called from gst_tag_list_copy_value() when

 * it is required that one or more values for a tag be condensed into

 * one single value. This may happen from gst_tag_list_get_string(),

 * gst_tag_list_get_int(), gst_tag_list_get_double() etc. What will happen

 * exactly in that case depends on how the tag was registered and if a

 * merge function was supplied and if so which one.

 *

 * Two default merge functions are provided: gst_tag_merge_use_first() and

 * gst_tag_merge_strings_with_comma().

 */

void

gst_tag_register (const gchar * name, GstTagFlag flag, GType type,

    const gchar * nick, const gchar * blurb, GstTagMergeFunc func)

{

  g_return_if_fail (name != NULL);

  g_return_if_fail (nick != NULL);

  g_return_if_fail (blurb != NULL);

  g_return_if_fail (type != 0 && type != GST_TYPE_LIST);

  gst_tag_register_static (g_intern_string (name), flag, type,

      g_intern_string (nick), g_intern_string (blurb), func);

}

/**

 * gst_tag_register_static:

 * @name: the name or identifier string (string constant)

 * @flag: a flag describing the type of tag info

 * @type: the type this data is in

 * @nick: human-readable name or short description (string constant)

 * @blurb: a human-readable description for this tag (string constant)

 * @func: (allow-none) (scope call): function for merging multiple values of this tag, or %NULL

 *

 * Registers a new tag type for the use with GStreamer's type system.

 *

 * Same as gst_tag_register(), but @name, @nick, and @blurb must be

 * static strings or inlined strings, as they will not be copied. (GStreamer

 * plugins will be made resident once loaded, so this function can be used

 * even from dynamically loaded plugins.)

 */

void

gst_tag_register_static (const gchar * name, GstTagFlag flag, GType type,

    const gchar * nick, const gchar * blurb, GstTagMergeFunc func)

{

  GstTagInfo *info;

  g_return_if_fail (name != NULL);

  g_return_if_fail (nick != NULL);

  g_return_if_fail (blurb != NULL);

  g_return_if_fail (type != 0 && type != GST_TYPE_LIST);

  info = gst_tag_lookup (name);

  if (info) {

    g_return_if_fail (info->type == type);

    return;

  }

  info = g_slice_new (GstTagInfo);

  info->flag = flag;

  info->type = type;

  info->name_quark = g_quark_from_static_string (name);

  info->nick = nick;

  info->blurb = blurb;

  info->merge_func = func;

  TAG_LOCK;

  g_hash_table_insert (__tags, (gpointer) name, info);

  TAG_UNLOCK;

}

/**

 * gst_tag_exists:

 * @tag: name of the tag

 *

 * Checks if the given type is already registered.

 *

 * Returns: %TRUE if the type is already registered

 */

gboolean

gst_tag_exists (const gchar * tag)

{

  g_return_val_if_fail (tag != NULL, FALSE);

  return gst_tag_lookup (tag) != NULL;

}

/**

 * gst_tag_get_type:

 * @tag: the tag

 *

 * Gets the #GType used for this tag.

 *

 * Returns: the #GType of this tag

 */

GType

gst_tag_get_type (const gchar * tag)

{

  GstTagInfo *info;

  g_return_val_if_fail (tag != NULL, 0);

  info = gst_tag_lookup (tag);

  g_return_val_if_fail (info != NULL, 0);

  return info->type;

}

/**

 * gst_tag_get_nick:

 * @tag: the tag

 *

 * Returns the human-readable name of this tag, You must not change or free

 * this string.

 *

 * Returns: (nullable): the human-readable name of this tag

 */

const gchar *

gst_tag_get_nick (const gchar * tag)

{

  GstTagInfo *info;

  g_return_val_if_fail (tag != NULL, NULL);

  info = gst_tag_lookup (tag);

  if (!info) {

    GST_WARNING ("Uknown tag: %s", tag);

    return tag;

  }

  return info->nick;

}

/**

 * gst_tag_get_description:

 * @tag: the tag

 *

 * Returns the human-readable description of this tag, You must not change or

 * free this string.

 *

 * Returns: (nullable): the human-readable description of this tag

 */

const gchar *

gst_tag_get_description (const gchar * tag)

{

  GstTagInfo *info;

  g_return_val_if_fail (tag != NULL, NULL);

  info = gst_tag_lookup (tag);

  g_return_val_if_fail (info != NULL, NULL);

  return info->blurb;

}

/**

 * gst_tag_get_flag:

 * @tag: the tag

 *

 * Gets the flag of @tag.

 *

 * Returns: the flag of this tag.

 */

GstTagFlag

gst_tag_get_flag (const gchar * tag)

{

  GstTagInfo *info;

  g_return_val_if_fail (tag != NULL, GST_TAG_FLAG_UNDEFINED);

  info = gst_tag_lookup (tag);

  g_return_val_if_fail (info != NULL, GST_TAG_FLAG_UNDEFINED);

  return info->flag;

}

/**

 * gst_tag_is_fixed:

 * @tag: tag to check

 *

 * Checks if the given tag is fixed. A fixed tag can only contain one value.

 * Unfixed tags can contain lists of values.

 *

 * Returns: %TRUE, if the given tag is fixed.

 */

gboolean

gst_tag_is_fixed (const gchar * tag)

{

  GstTagInfo *info;

  g_return_val_if_fail (tag != NULL, FALSE);

  info = gst_tag_lookup (tag);

  g_return_val_if_fail (info != NULL, FALSE);

  return info->merge_func == NULL;

}

/* takes ownership of the structure */

static GstTagList *

gst_tag_list_new_internal (GstStructure * s, GstTagScope scope)

{

  GstTagList *tag_list;

  g_assert (s != NULL);

  tag_list = (GstTagList *) g_slice_new (GstTagListImpl);

  gst_mini_object_init (GST_MINI_OBJECT_CAST (tag_list), 0, GST_TYPE_TAG_LIST,

      (GstMiniObjectCopyFunction) __gst_tag_list_copy, NULL,

      (GstMiniObjectFreeFunction) __gst_tag_list_free);

  GST_TAG_LIST_STRUCTURE (tag_list) = s;

  GST_TAG_LIST_SCOPE (tag_list) = scope;

#ifdef DEBUG_REFCOUNT

  GST_CAT_TRACE (GST_CAT_TAGS, "created taglist %p", tag_list);

#endif

  return tag_list;

}

static void

__gst_tag_list_free (GstTagList * list)

{

  g_return_if_fail (GST_IS_TAG_LIST (list));

#ifdef DEBUG_REFCOUNT

  GST_CAT_TRACE (GST_CAT_TAGS, "freeing taglist %p", list);

#endif

  gst_structure_free (GST_TAG_LIST_STRUCTURE (list));

  g_slice_free1 (sizeof (GstTagListImpl), list);

}

static GstTagList *

__gst_tag_list_copy (const GstTagList * list)

{

  const GstStructure *s;

  g_return_val_if_fail (GST_IS_TAG_LIST (list), NULL);

  s = GST_TAG_LIST_STRUCTURE (list);

  return gst_tag_list_new_internal (gst_structure_copy (s),

      GST_TAG_LIST_SCOPE (list));

}

/**

 * gst_tag_list_new_empty:

 *

 * Creates a new empty GstTagList.

 *

 * Free-function: gst_tag_list_unref

 *

 * Returns: (transfer full): An empty tag list

 */

GstTagList *

gst_tag_list_new_empty (void)

{

  GstStructure *s;

  GstTagList *tag_list;

  s = gst_structure_new_id_empty (GST_QUARK (TAGLIST));

  tag_list = gst_tag_list_new_internal (s, GST_TAG_SCOPE_STREAM);

  return tag_list;

}

/**

 * gst_tag_list_new:

 * @tag: tag

 * @...: %NULL-terminated list of values to set

 *

 * Creates a new taglist and appends the values for the given tags. It expects

 * tag-value pairs like gst_tag_list_add(), and a %NULL terminator after the

 * last pair. The type of the values is implicit and is documented in the API

 * reference, but can also be queried at runtime with gst_tag_get_type(). It

 * is an error to pass a value of a type not matching the tag type into this

 * function. The tag list will make copies of any arguments passed

 * (e.g. strings, buffers).

 *

 * After creation you might also want to set a #GstTagScope on the returned

 * taglist to signal if the contained tags are global or stream tags. By

 * default stream scope is assumes. See gst_tag_list_set_scope().

 *

 * Free-function: gst_tag_list_unref

 *

 * Returns: (transfer full): a new #GstTagList. Free with gst_tag_list_unref()

 *     when no longer needed.

 */

GstTagList *

gst_tag_list_new (const gchar * tag, ...)

{

  GstTagList *list;

  va_list args;

  g_return_val_if_fail (tag != NULL, NULL);

  list = gst_tag_list_new_empty ();

  va_start (args, tag);

  gst_tag_list_add_valist (list, GST_TAG_MERGE_APPEND, tag, args);

  va_end (args);

  return list;

}

/**

 * gst_tag_list_new_valist:

 * @var_args: tag / value pairs to set

 *

 * Just like gst_tag_list_new(), only that it takes a va_list argument.

 * Useful mostly for language bindings.

 *

 * Free-function: gst_tag_list_unref

 *

 * Returns: (transfer full): a new #GstTagList. Free with gst_tag_list_unref()

 *     when no longer needed.

 */

GstTagList *

gst_tag_list_new_valist (va_list var_args)

{

  GstTagList *list;

  const gchar *tag;

  list = gst_tag_list_new_empty ();

  tag = va_arg (var_args, gchar *);

  gst_tag_list_add_valist (list, GST_TAG_MERGE_APPEND, tag, var_args);

  return list;

}

/**

 * gst_tag_list_set_scope:

 * @list: a #GstTagList

 * @scope: new scope for @list

 *

 * Sets the scope of @list to @scope. By default the scope

 * of a taglist is stream scope.

 *

 */

void

gst_tag_list_set_scope (GstTagList * list, GstTagScope scope)

{

  g_return_if_fail (GST_IS_TAG_LIST (list));

  g_return_if_fail (gst_tag_list_is_writable (list));

  GST_TAG_LIST_SCOPE (list) = scope;

}

/**

 * gst_tag_list_get_scope:

 * @list: a #GstTagList

 *

 * Gets the scope of @list.

 *

 * Returns: The scope of @list

 */

GstTagScope

gst_tag_list_get_scope (const GstTagList * list)

{

  g_return_val_if_fail (GST_IS_TAG_LIST (list), GST_TAG_SCOPE_STREAM);

  return GST_TAG_LIST_SCOPE (list);

}

/**

 * gst_tag_list_to_string:

 * @list: a #GstTagList

 *

 * Serializes a tag list to a string.

 *

 * Returns: (nullable): a newly-allocated string, or %NULL in case of

 *     an error. The string must be freed with g_free() when no longer

 *     needed.

 */

gchar *

gst_tag_list_to_string (const GstTagList * list)

{

  g_return_val_if_fail (GST_IS_TAG_LIST (list), NULL);

  return gst_structure_to_string (GST_TAG_LIST_STRUCTURE (list));

}

/**

 * gst_tag_list_new_from_string:

 * @str: a string created with gst_tag_list_to_string()

 *

 * Deserializes a tag list.

 *

 * Returns: (nullable): a new #GstTagList, or %NULL in case of an

 * error.