playlist/xspf: use tag_table to convert element name to TagType

src/playlist/plugins/XspfPlaylistPlugin.cxx

@@ -23,6 +23,7 @@
 #include "song/DetachedSong.hxx"
 #include "input/InputStream.hxx"
 #include "tag/Builder.hxx"
+#include "tag/Table.hxx"
 #include "util/StringView.hxx"
 #include "lib/expat/ExpatParser.hxx"
 #include "Log.hxx"
@@ -62,6 +63,19 @@ struct XspfParser {
 	TagBuilder tag_builder;
 };
 
+static constexpr struct tag_table xspf_tag_elements[] = {
+	{ "title", TAG_TITLE },
+
+	/* TAG_COMPOSER would be more correct according to the XSPF
+	   spec */
+	{ "creator", TAG_ARTIST },
+
+	{ "annotation", TAG_COMMENT },
+	{ "album", TAG_ALBUM },
+	{ "trackNum", TAG_TRACK },
+	{ nullptr, TAG_NUM_OF_ITEM_TYPES }
+};
+
 static void XMLCALL
 xspf_start_element(void *user_data, const XML_Char *element_name,
 		   gcc_unused const XML_Char **atts)
@@ -93,18 +107,9 @@ xspf_start_element(void *user_data, const XML_Char *element_name,
 	case XspfParser::TRACK:
 		if (strcmp(element_name, "location") == 0)
 			parser->state = XspfParser::LOCATION;
-		else if (strcmp(element_name, "title") == 0)
-			parser->tag_type = TAG_TITLE;
-		else if (strcmp(element_name, "creator") == 0)
-			/* TAG_COMPOSER would be more correct
-			   according to the XSPF spec */
-			parser->tag_type = TAG_ARTIST;
-		else if (strcmp(element_name, "annotation") == 0)
-			parser->tag_type = TAG_COMMENT;
-		else if (strcmp(element_name, "album") == 0)
-			parser->tag_type = TAG_ALBUM;
-		else if (strcmp(element_name, "trackNum") == 0)
-			parser->tag_type = TAG_TRACK;
+		else
+			parser->tag_type = tag_table_lookup(xspf_tag_elements,
+							    element_name);
 
 		break;