tag: added tag "AlbumArtistSort"

The tag_id3.c library supports both the documented "TSO2" tag, and the
inofficial TXXX/ALBUMARTISTSORT.

The Vorbis/FLAC decoder automatically supports the new tag, without
further change.

NEWS

@@ -3,6 +3,8 @@ ver 0.16 (20??/??/??)
   - send song modification time to client
   - added "update" idle event
   - removed the deprecated "volume" command
+* tags:
+  - added tag "AlbumArtistSort"
 * decoders:
   - ffmpeg: support multiple tags
 * mixers:

src/tag.c

@@ -45,6 +45,7 @@ const char *tag_item_names[TAG_NUM_OF_ITEM_TYPES] = {
 	"Artist",
 	"Album",
 	"AlbumArtist",
+	[TAG_ALBUM_ARTIST_SORT] = "AlbumArtistSort",
 	"Title",
 	"Track",
 	"Name",

src/tag.h

@@ -34,6 +34,7 @@ enum tag_type {
 	TAG_ITEM_ARTIST,
 	TAG_ITEM_ALBUM,
 	TAG_ITEM_ALBUM_ARTIST,
+	TAG_ALBUM_ARTIST_SORT,
 	TAG_ITEM_TITLE,
 	TAG_ITEM_TRACK,
 	TAG_ITEM_NAME,

src/tag_id3.c

@@ -237,6 +237,7 @@ tag_id3_parse_txxx_name(const char *name)
 		enum tag_type type;
 		const char *name;
 	} musicbrainz_txxx[] = {
+		{ TAG_ALBUM_ARTIST_SORT, "ALBUMARTISTSORT" },
 		{ TAG_MUSICBRAINZ_ARTISTID, "MusicBrainz Artist Id" },
 		{ TAG_MUSICBRAINZ_ALBUMID, "MusicBrainz Album Id" },
 		{ TAG_MUSICBRAINZ_ALBUMARTISTID,
@@ -332,7 +333,7 @@ struct tag *tag_id3_import(struct id3_tag * tag)
 	getID3Info(tag, ID3_FRAME_ALBUM_ARTIST,
 		   TAG_ITEM_ALBUM_ARTIST, ret);
 	getID3Info(tag, ID3_FRAME_ALBUM_ARTIST_SORT,
-		   TAG_ITEM_ALBUM_ARTIST, ret);
+		   TAG_ALBUM_ARTIST_SORT, ret);
 	getID3Info(tag, ID3_FRAME_TITLE, TAG_ITEM_TITLE, ret);
 	getID3Info(tag, ID3_FRAME_ALBUM, TAG_ITEM_ALBUM, ret);
 	getID3Info(tag, ID3_FRAME_TRACK, TAG_ITEM_TRACK, ret);