tag_table: convert to a struct

The struct is smaller because it is sparse.  Its traversal is also
more efficient.

3 files changed, 22 insertions, 14 deletions

diff --git a/src/decoder/mp4ff_decoder_plugin.c b/src/decoder/mp4ff_decoder_plugin.c
index 89f65670..6202ece9 100644
--- a/src/decoder/mp4ff_decoder_plugin.c
+++ b/src/decoder/mp4ff_decoder_plugin.c
@@ -356,16 +356,17 @@ mp4_decode(struct decoder *mpd_decoder, struct input_stream *input_stream)
 	mp4ff_close(mp4fh);
 }
 
-static const char *const mp4ff_tag_names[TAG_NUM_OF_ITEM_TYPES] = {
-	[TAG_ALBUM_ARTIST] = "album artist",
-	[TAG_COMPOSER] = "writer",
-	[TAG_PERFORMER] = "band",
+static const struct tag_table mp4ff_tags[] = {
+	{ "album artist", TAG_ALBUM_ARTIST },
+	{ "writer", TAG_COMPOSER },
+	{ "band", TAG_PERFORMER },
+	{ NULL, TAG_NUM_OF_ITEM_TYPES }
 };
 
 static enum tag_type
 mp4ff_tag_name_parse(const char *name)
 {
-	enum tag_type type = tag_table_lookup(mp4ff_tag_names, name);
+	enum tag_type type = tag_table_lookup_i(mp4ff_tags, name);
 	if (type == TAG_NUM_OF_ITEM_TYPES)
 		type = tag_name_parse_i(name);
 
diff --git a/src/tag_ape.c b/src/tag_ape.c
index 1978ea39..5a30531c 100644
--- a/src/tag_ape.c
+++ b/src/tag_ape.c
@@ -23,15 +23,16 @@
 #include "tag_table.h"
 #include "ape.h"
 
-static const char *const ape_tag_names[TAG_NUM_OF_ITEM_TYPES] = {
-	[TAG_ALBUM_ARTIST] = "album artist",
-	[TAG_DATE] = "year",
+static const struct tag_table ape_tags[] = {
+	{ "album artist", TAG_ALBUM_ARTIST },
+	{ "year", TAG_DATE },
+	{ NULL, TAG_NUM_OF_ITEM_TYPES }
 };
 
 static enum tag_type
 tag_ape_name_parse(const char *name)
 {
-	enum tag_type type = tag_table_lookup(ape_tag_names, name);
+	enum tag_type type = tag_table_lookup_i(ape_tags, name);
 	if (type == TAG_NUM_OF_ITEM_TYPES)
 		type = tag_name_parse_i(name);
 
diff --git a/src/tag_table.h b/src/tag_table.h
index 367a3de5..ecb3805d 100644
--- a/src/tag_table.h
+++ b/src/tag_table.h
@@ -24,18 +24,24 @@
 
 #include <glib.h>
 
+struct tag_table {
+	const char *name;
+
+	enum tag_type type;
+};
+
 /**
  * Looks up a string in a tag translation table (case insensitive).
  * Returns TAG_NUM_OF_ITEM_TYPES if the specified name was not found
  * in the table.
  */
+G_GNUC_PURE
 static inline enum tag_type
-tag_table_lookup(const char *const* table, const char *name)
+tag_table_lookup_i(const struct tag_table *table, const char *name)
 {
-	for (unsigned i = 0; i < TAG_NUM_OF_ITEM_TYPES; i++)
-		if (table[i] != NULL &&
-		    g_ascii_strcasecmp(name, table[i]) == 0)
-			return (enum tag_type)i;
+	for (; table->name != NULL; ++table)
+		if (g_ascii_strcasecmp(name, table->name) == 0)
+			return table->type;
 
 	return TAG_NUM_OF_ITEM_TYPES;
 }