Merge string trimming for id3v1 into single method

id3v1.go

@@ -54,17 +54,17 @@ func ReadID3v1Tags(r io.ReadSeeker) (Metadata, error) {
 		return nil, ErrNotID3v1
 	}
 
-	title, err := readStringTrimNULL(r, 30)
+	title, err := readString(r, 30)
 	if err != nil {
 		return nil, err
 	}
 
-	artist, err := readStringTrimNULL(r, 30)
+	artist, err := readString(r, 30)
 	if err != nil {
 		return nil, err
 	}
 
-	album, err := readStringTrimNULL(r, 30)
+	album, err := readString(r, 30)
 	if err != nil {
 		return nil, err
 	}
@@ -82,10 +82,10 @@ func ReadID3v1Tags(r io.ReadSeeker) (Metadata, error) {
 	var comment string
 	var track int
 	if commentBytes[28] == 0 {
-		comment = strings.TrimSpace(string(commentBytes[:28]))
+		comment = trimString(string(commentBytes[:28]))
 		track = int(commentBytes[29])
 	} else {
-		comment = strings.TrimSpace(string(commentBytes))
+		comment = trimString(string(commentBytes))
 	}
 
 	var genre string
@@ -98,17 +98,21 @@ func ReadID3v1Tags(r io.ReadSeeker) (Metadata, error) {
 	}
 
 	m := make(map[string]interface{})
-	m["title"] = strings.TrimSpace(title)
-	m["artist"] = strings.TrimSpace(artist)
-	m["album"] = strings.TrimSpace(album)
-	m["year"] = strings.TrimSpace(year)
-	m["comment"] = strings.TrimSpace(comment)
+	m["title"] = trimString(title)
+	m["artist"] = trimString(artist)
+	m["album"] = trimString(album)
+	m["year"] = trimString(year)
+	m["comment"] = trimString(comment)
 	m["track"] = track
 	m["genre"] = genre
 
 	return metadataID3v1(m), nil
 }
 
+func trimString(x string) string {
+	return strings.TrimSpace(strings.Trim(x, "\x00"))
+}
+
 // metadataID3v1 is the implementation of Metadata used for ID3v1 tags.
 type metadataID3v1 map[string]interface{}