Add comments to common fields

id3.go

@@ -16,6 +16,7 @@ type Tagger interface {
 	Album() string
 	Year() string
 	Genre() string
+	Comments() []string
 	SetTitle(string)
 	SetArtist(string)
 	SetAlbum(string)

id3v2.go

@@ -177,6 +177,20 @@ func (t Tag) Genre() string {
 	return t.textFrameText(t.commonMap["Genre"])
 }
 
+func (t Tag) Comments() []string {
+	frames := t.Frames(t.commonMap["Comments"])
+	if frames == nil {
+		return nil
+	}
+
+	comments := make([]string, len(frames))
+	for i, frame := range frames {
+		comments[i] = frame.String()
+	}
+
+	return comments
+}
+
 func (t *Tag) SetTitle(text string) {
 	t.setTextFrameText(t.commonMap["Title"], text)
 }

id3v22.go

@@ -14,18 +14,19 @@ const (
 var (
 	// Common frame IDs
 	V22CommonFrame = map[string]string{
-		"Title":  "TT2",
-		"Artist": "TP1",
-		"Album":  "TAL",
-		"Year":   "TYE",
-		"Genre":  "TCO",
+		"Title":    "TT2",
+		"Artist":   "TP1",
+		"Album":    "TAL",
+		"Year":     "TYE",
+		"Genre":    "TCO",
+		"Comments": "COM",
 	}
 
 	// V22FrameTypeMap specifies the frame IDs and constructors allowed in ID3v2.2
 	V22FrameTypeMap = map[string]FrameType{
 		"BUF": FrameType{id: "BUF", description: "Recommended buffer size", constructor: NewDataFrame},
 		"CNT": FrameType{id: "CNT", description: "Play counter", constructor: NewDataFrame},
-		"COM": FrameType{id: "COM", description: "Comments", constructor: NewDataFrame},
+		"COM": FrameType{id: "COM", description: "Comments", constructor: NewUnsynchTextFrame},
 		"CRA": FrameType{id: "CRA", description: "Audio encryption", constructor: NewDataFrame},
 		"CRM": FrameType{id: "CRM", description: "Encrypted meta frame", constructor: NewDataFrame},
 		"ETC": FrameType{id: "ETC", description: "Event timing codes", constructor: NewDataFrame},

id3v23.go

@@ -10,11 +10,12 @@ import (
 var (
 	// Common frame IDs
 	V23CommonFrame = map[string]string{
-		"Title":  "TIT2",
-		"Artist": "TPE1",
-		"Album":  "TALB",
-		"Year":   "TYER",
-		"Genre":  "TCON",
+		"Title":    "TIT2",
+		"Artist":   "TPE1",
+		"Album":    "TALB",
+		"Year":     "TYER",
+		"Genre":    "TCON",
+		"Comments": "COMM",
 	}
 
 	// V23DeprecatedTypeMap contains deprecated frame IDs from ID3v2.2
@@ -40,7 +41,7 @@ var (
 	V23FrameTypeMap = map[string]FrameType{
 		"AENC": FrameType{id: "AENC", description: "Audio encryption", constructor: NewDataFrame},
 		"APIC": FrameType{id: "APIC", description: "Attached picture", constructor: NewImageFrame},
-		"COMM": FrameType{id: "COMM", description: "Comments", constructor: NewDataFrame},
+		"COMM": FrameType{id: "COMM", description: "Comments", constructor: NewUnsynchTextFrame},
 		"COMR": FrameType{id: "COMR", description: "Commercial frame", constructor: NewDataFrame},
 		"ENCR": FrameType{id: "ENCR", description: "Encryption method registration", constructor: NewDataFrame},
 		"EQUA": FrameType{id: "EQUA", description: "Equalization", constructor: NewDataFrame},