tag_id3: support multiple values

NEWS

@@ -20,6 +20,7 @@ ver 0.16 (20??/??/??)
 * tags:
   - added tags "ArtistSort", "AlbumArtistSort"
   - id3: revised "performer" tag support
+  - id3: support multiple values
   - ape: MusicBrainz tags
   - ape: support multiple values
 * decoders:

src/tag_id3.c

@@ -126,17 +126,16 @@ import_id3_string(bool is_id3v1, const id3_ucs4_t *ucs4)
  * - string list
  */
 static void
-tag_id3_import_text(struct tag *dest, struct id3_tag *tag, const char *id,
+tag_id3_import_text_frame(struct tag *dest, struct id3_tag *tag,
+			  const struct id3_frame *frame,
 			  enum tag_type type)
 {
-	struct id3_frame const *frame;
 	id3_ucs4_t const *ucs4;
 	id3_utf8_t *utf8;
 	union id3_field const *field;
 	unsigned int nstrings, i;
 
-	frame = id3_tag_findframe(tag, id, 0);
-	if (frame == NULL || frame->nfields != 2)
+	if (frame->nfields != 2)
 		return;
 
 	/* check the encoding field */
@@ -171,6 +170,20 @@ tag_id3_import_text(struct tag *dest, struct id3_tag *tag, const char *id,
 }
 
 /**
+ * Import all text frames with the specified id (ID3v2.4.0 section
+ * 4.2).  This is a wrapper for tag_id3_import_text_frame().
+ */
+static void
+tag_id3_import_text(struct tag *dest, struct id3_tag *tag, const char *id,
+		    enum tag_type type)
+{
+	const struct id3_frame *frame;
+	for (unsigned i = 0;
+	     (frame = id3_tag_findframe(tag, id, i)) != NULL; ++i)
+		tag_id3_import_text_frame(dest, tag, frame, type);
+}
+
+/**
  * Import a "Comment frame" (ID3v2.4.0 section 4.10).  It
  * contains 4 fields:
  *
@@ -180,16 +193,15 @@ tag_id3_import_text(struct tag *dest, struct id3_tag *tag, const char *id,
  * - full string (we use this one)
  */
 static void
-tag_id3_import_comment(struct tag *dest, struct id3_tag *tag, const char *id,
+tag_id3_import_comment_frame(struct tag *dest, struct id3_tag *tag,
+			     const struct id3_frame *frame,
 			     enum tag_type type)
 {
-	struct id3_frame const *frame;
 	id3_ucs4_t const *ucs4;
 	id3_utf8_t *utf8;
 	union id3_field const *field;
 
-	frame = id3_tag_findframe(tag, id, 0);
-	if (frame == NULL || frame->nfields != 4)
+	if (frame->nfields != 4)
 		return;
 
 	/* for now I only read the 4th field, with the fullstring */
@@ -210,6 +222,20 @@ tag_id3_import_comment(struct tag *dest, struct id3_tag *tag, const char *id,
 }
 
 /**
+ * Import all comment frames (ID3v2.4.0 section 4.10).  This is a
+ * wrapper for tag_id3_import_comment_frame().
+ */
+static void
+tag_id3_import_comment(struct tag *dest, struct id3_tag *tag, const char *id,
+		       enum tag_type type)
+{
+	const struct id3_frame *frame;
+	for (unsigned i = 0;
+	     (frame = id3_tag_findframe(tag, id, i)) != NULL; ++i)
+		tag_id3_import_comment_frame(dest, tag, frame, type);
+}
+
+/**
  * Parse a TXXX name, and convert it to a tag_type enum value.
  * Returns TAG_NUM_OF_ITEM_TYPES if the TXXX name is not understood.
  */