Initial commit

id3v2metadata.go

@@ -0,0 +1,121 @@
+// Copyright 2015, David Howden
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tag
+
+import (
+	"strconv"
+	"strings"
+)
+
+type frameNames map[string][2]string
+
+func (f frameNames) Name(s string, fm Format) string {
+	l, ok := f[s]
+	if !ok {
+		return ""
+	}
+
+	switch fm {
+	case ID3v2_2:
+		return l[0]
+	case ID3v2_3, ID3v2_4:
+		return l[1]
+	}
+	return ""
+}
+
+var frames = frameNames(map[string][2]string{
+	"title":        [2]string{"TT2", "TIT2"},
+	"artist":       [2]string{"TP1", "TPE1"},
+	"album":        [2]string{"TAL", "TALB"},
+	"album_artist": [2]string{"TP2", "TPE2"},
+	"composer":     [2]string{"TCM", "TCOM"},
+	"year":         [2]string{"TYE", "TYER"},
+	"track":        [2]string{"TRK", "TRCK"},
+	"disc":         [2]string{"TPA", "TPOS"},
+	"genre":        [2]string{"TCO", "TCON"},
+	"picture":      [2]string{"PIC", "APIC"},
+})
+
+// metadataID3v2 is the implementation of Metadata used for ID3v2 tags.
+type metadataID3v2 struct {
+	header *ID3v2Header
+	frames map[string]interface{}
+}
+
+func (m metadataID3v2) getString(k string) string {
+	v, ok := m.frames[k]
+	if !ok {
+		return ""
+	}
+	return v.(string)
+}
+
+func (m metadataID3v2) getInt(k string) int {
+	v, ok := m.frames[k]
+	if !ok {
+		return 0
+	}
+	return v.(int)
+}
+
+func (m metadataID3v2) Format() Format              { return m.header.Version }
+func (m metadataID3v2) Raw() map[string]interface{} { return m.frames }
+
+func (m metadataID3v2) Title() string {
+	return m.getString(frames.Name("title", m.Format()))
+}
+
+func (m metadataID3v2) Artist() string {
+	return m.getString(frames.Name("artist", m.Format()))
+}
+
+func (m metadataID3v2) Album() string {
+	return m.getString(frames.Name("album", m.Format()))
+}
+
+func (m metadataID3v2) AlbumArtist() string {
+	return m.getString(frames.Name("album_artist", m.Format()))
+}
+
+func (m metadataID3v2) Composer() string {
+	return m.getString(frames.Name("composer", m.Format()))
+}
+
+func (m metadataID3v2) Genre() string {
+	return m.getString(frames.Name("genre", m.Format()))
+}
+
+func (m metadataID3v2) Year() int {
+	year, _ := strconv.Atoi(m.getString(frames.Name("year", m.Format())))
+	return year
+}
+
+func parseXofN(s string) (x, n int) {
+	xn := strings.Split(s, "/")
+	if len(xn) != 2 {
+		x, _ = strconv.Atoi(s)
+		return x, 0
+	}
+	x, _ = strconv.Atoi(strings.TrimSpace(xn[0]))
+	n, _ = strconv.Atoi(strings.TrimSpace(xn[1]))
+	return x, n
+}
+
+func (m metadataID3v2) Track() (int, int) {
+	return parseXofN(m.getString(frames.Name("track", m.Format())))
+}
+
+func (m metadataID3v2) Disc() (int, int) {
+	return parseXofN(m.getString(frames.Name("disc", m.Format())))
+}
+
+func (m metadataID3v2) Picture() *Picture {
+	v, ok := m.frames[frames.Name("picture", m.Format())]
+	if !ok {
+		return nil
+	}
+	return v.(*Picture)
+}