Minimal ID3v1.1 support ?

README.md

@@ -2,3 +2,4 @@
 ## Library for encoding/decoding ID3 tags
 
 # Under construction !
+## Bugs are a possibility rn in this state

id3v1.1.go

@@ -0,0 +1,125 @@
+package id3ed
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+)
+
+type ID3v11Tags struct {
+	SongName string
+	Artist   string
+	Album    string
+	Year     int
+	Comment  string
+	Track    int
+	Genre    int
+}
+
+// Retrieves ID3v1.1 field values of provided io.ReadSeeker (usually a file)
+func GetID3v11Tags(rs io.ReadSeeker) (*ID3v11Tags, error) {
+	// set reader to the last 128 bytes
+	_, err := rs.Seek(-int64(ID3V1SIZE), io.SeekEnd)
+	if err != nil {
+		return nil, fmt.Errorf("could not seek: %s", err)
+	}
+
+	tag, err := read(rs, 3)
+	if err != nil {
+		return nil, err
+	}
+
+	if !bytes.Equal(tag, []byte("TAG")) {
+		// no TAG, given file does not use ID3v1
+		return nil, fmt.Errorf("does not use ID3v1")
+	}
+
+	songname, err := read(rs, 30)
+	if err != nil {
+		return nil, err
+	}
+
+	artist, err := read(rs, 30)
+	if err != nil {
+		return nil, err
+	}
+
+	album, err := read(rs, 30)
+	if err != nil {
+		return nil, err
+	}
+
+	yearBytes, err := read(rs, 4)
+	if err != nil {
+		return nil, err
+	}
+	year, err := strconv.Atoi(string(yearBytes))
+	if err != nil {
+		return nil, fmt.Errorf("could not convert yearbytes into int: %s", err)
+	}
+
+	comment, err := read(rs, 28)
+	if err != nil {
+		return nil, err
+	}
+
+	// skip 1 null byte
+	_, err = read(rs, 1)
+	if err != nil {
+		return nil, err
+	}
+
+	trackByte, err := read(rs, 1)
+	if err != nil {
+		return nil, err
+	}
+
+	// track is one byte by specification
+	track := int(trackByte[0])
+
+	genreByte, err := read(rs, 1)
+	if err != nil {
+		return nil, err
+	}
+	// genre is one byte by specification
+	genre := int(genreByte[0])
+
+	return &ID3v11Tags{
+		SongName: string(songname),
+		Artist:   string(artist),
+		Album:    string(album),
+		Year:     year,
+		Comment:  string(comment),
+		Track:    track,
+		Genre:    genre,
+	}, nil
+}
+
+func (t *ID3v11Tags) GetSongName() string {
+	return t.SongName
+}
+
+func (t *ID3v11Tags) GetArtist() string {
+	return t.Artist
+}
+
+func (t *ID3v11Tags) GetAlbum() string {
+	return t.Album
+}
+
+func (t *ID3v11Tags) GetYear() int {
+	return t.Year
+}
+
+func (t *ID3v11Tags) GetComment() string {
+	return t.Comment
+}
+
+func (t *ID3v11Tags) GetTrack() int {
+	return t.Track
+}
+
+func (t *ID3v11Tags) GetGenre() int {
+	return t.Genre
+}

id3v1_test.go

@@ -0,0 +1,17 @@
+package id3ed
+
+import (
+	"os"
+	"testing"
+)
+
+func TestGetID3v1Tags(t *testing.T) {
+	testfile, err := os.Open("./testData/id3v1.txt")
+	if err != nil {
+		t.Errorf("could not open file for testing: %s", err)
+	}
+	_, err = GetID3v1Tags(testfile)
+	if err != nil {
+		t.Errorf("GetID3v1Tags failed: %s", err)
+	}
+}