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֍ Improved reading, fixed some bugs here and there ֍

main
Unbewohnte 3 years ago
parent
6624f21ece
commit
74e57f1857
13 changed files with 263 additions and 198 deletions
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  1. BIN
      testData/testreadv2.mp3
  2. BIN
      testData/testwritev2.mp3
  3. 66
      util/conversion.go
  4. 21
      util/conversion_test.go
  5. 81
      util/text.go
  6. 37
      util/text_test.go
  7. 10
      v2/constants.go
  8. 3
      v2/errors.go
  9. 116
      v2/frame.go
  10. 4
      v2/frame_test.go
  11. 43
      v2/read.go
  12. 31
      v2/write.go
  13. 49
      v2/write_test.go

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66
util/conversion.go
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@ -2,9 +2,6 @@ package util
import (
"encoding/binary"
"strings"
euni "golang.org/x/text/encoding/unicode"
)
// got the logic from: https://github.com/bogem/id3v2 , thank you very much.
@ -64,66 +61,3 @@ func IntToBytesSynchsafe(gInt uint32) []byte {
}
return synchsafeIBytes
}
// Converts given bytes into string, ignoring the first 31 non-printable ASCII characters.
// (LOSSY, if given bytes contain some nasty ones)
func ToStringLossy(gBytes []byte) string {
var runes []rune
for _, b := range gBytes {
if b <= 31 {
continue
}
runes = append(runes, rune(b))
}
return strings.ToValidUTF8(string(runes), "")
}
const (
EncodingISO8859 byte = iota
EncodingUTF16BOM
EncodingUTF16
EncodingUTF8
)
// Decodes the given frame`s contents
func DecodeText(fContents []byte) string {
textEncoding := fContents[0] // the first byte is the encoding
switch textEncoding {
case EncodingISO8859:
// ISO-8859-1
return ToStringLossy(fContents[1:])
case EncodingUTF16BOM:
// UTF-16 with BOM
encoding := euni.UTF16(euni.BigEndian, euni.ExpectBOM)
decoder := encoding.NewDecoder()
decodedBytes := make([]byte, len(fContents)*2)
_, _, err := decoder.Transform(decodedBytes, fContents[1:], true)
if err != nil {
return ""
}
return string(decodedBytes)
case EncodingUTF16:
// UTF-16
encoding := euni.UTF16(euni.BigEndian, euni.IgnoreBOM)
decoder := encoding.NewDecoder()
decodedBytes := make([]byte, len(fContents)*2)
_, _, err := decoder.Transform(decodedBytes, fContents[1:], true)
if err != nil {
return ""
}
return string(decodedBytes)
case EncodingUTF8:
// UTF-8
return ToStringLossy(fContents[1:])
}
return ""
}

21
util/conversion_test.go
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@ -6,27 +6,6 @@ import (
"testing"
)
func TestToStringLossy(t *testing.T) {
someVeryNastyBytes := []byte{0, 1, 2, 3, 4, 5, 6, 50, 7, 8, 9, 10, 11, 50, 50}
gString := ToStringLossy(someVeryNastyBytes)
if gString != "222" {
t.Errorf("ToString failed: expected output: %s; got %s", "222", gString)
}
}
func TestDecodeText(t *testing.T) {
// 3 - UTF-8 encoding
someFrameContents := []byte{3, 50, 50, 50, 50, 0, 0, 0, 0, 50}
decodedUtf8text := DecodeText(someFrameContents)
if decodedUtf8text != "22222" {
t.Errorf("DecodeText failed: expected text %s, got %s", "22222", decodedUtf8text)
}
}
func TestIntToBytesSynchsafe(t *testing.T) {
testInts := []uint32{
1234,

81
util/text.go
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@ -0,0 +1,81 @@
package util
import (
"strings"
"unicode"
euni "golang.org/x/text/encoding/unicode"
)
// Checks if given characters are in ASCII range
func InASCII(chars string) bool {
for i := 0; i < len(chars); i++ {
if chars[i] > unicode.MaxASCII {
return false
}
}
return true
}
// Converts given bytes into string, ignoring the first 31 non-printable ASCII characters.
// (LOSSY, if given bytes contain some nasty ones)
func ToStringLossy(gBytes []byte) string {
var runes []rune
for _, b := range gBytes {
if b <= 31 {
continue
}
runes = append(runes, rune(b))
}
return strings.ToValidUTF8(string(runes), "")
}
const (
EncodingISO8859 byte = iota
EncodingUTF16BOM
EncodingUTF16
EncodingUTF8
)
// Decodes the given frame`s contents
func DecodeText(fContents []byte) string {
textEncoding := fContents[0] // the first byte is the encoding
switch textEncoding {
case EncodingISO8859:
// ISO-8859-1
return ToStringLossy(fContents[1:])
case EncodingUTF16BOM:
// UTF-16 with BOM
encoding := euni.UTF16(euni.BigEndian, euni.ExpectBOM)
decoder := encoding.NewDecoder()
decodedBytes := make([]byte, len(fContents)*2)
_, _, err := decoder.Transform(decodedBytes, fContents[1:], true)
if err != nil {
return ""
}
return string(decodedBytes)
case EncodingUTF16:
// UTF-16
encoding := euni.UTF16(euni.BigEndian, euni.IgnoreBOM)
decoder := encoding.NewDecoder()
decodedBytes := make([]byte, len(fContents)*2)
_, _, err := decoder.Transform(decodedBytes, fContents[1:], true)
if err != nil {
return ""
}
return string(decodedBytes)
case EncodingUTF8:
// UTF-8
return ToStringLossy(fContents[1:])
}
return ""
}

37
util/text_test.go
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@ -0,0 +1,37 @@
package util
import "testing"
func TestToStringLossy(t *testing.T) {
someVeryNastyBytes := []byte{0, 1, 2, 3, 4, 5, 6, 50, 7, 8, 9, 10, 11, 50, 50}
gString := ToStringLossy(someVeryNastyBytes)
if gString != "222" {
t.Errorf("ToString failed: expected output: %s; got %s", "222", gString)
}
}
func TestDecodeText(t *testing.T) {
// 3 - UTF-8 encoding
someFrameContents := []byte{3, 50, 50, 50, 50, 0, 0, 0, 0, 50}
decodedUtf8text := DecodeText(someFrameContents)
if decodedUtf8text != "22222" {
t.Errorf("DecodeText failed: expected text %s, got %s", "22222", decodedUtf8text)
}
}
func TestInASCII(t *testing.T) {
asciiChars := "All these characters are in ASCII table ()^&$*!@$&%#"
nonASCII := "These are not ᗜˬᗜ FUMO"
if !InASCII(asciiChars) {
t.Errorf("InASCII failed: expected %s to be in ASCII table", asciiChars)
}
if InASCII(nonASCII) {
t.Errorf("InASCII failed: expected %s not to be in ASCII table", nonASCII)
}
}

10
v2/constants.go
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@ -1,12 +1,12 @@
package v2
const HEADERIDENTIFIER string = "ID3"
const HEADERSIZE int = 10 // bytes
const HEADERMAXSIZE int = 268435456 // bytes (256 MB)
const HEADERSIZE int = 10
const V2_2 string = "ID3v2.2"
const V2_3 string = "ID3v2.3"
const V2_4 string = "ID3v2.4"
const V2_2FrameIDSize uint = 3
const V2_3FrameIDSize uint = 4
const V2_4FrameIDSize uint = 4
const V2_2FrameHeaderSize uint = 6
const V2_3FrameHeaderSize uint = 10
const V2_4FrameHeaderSize uint = V2_3FrameHeaderSize

3
v2/errors.go
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@ -5,3 +5,6 @@ package v2
import "fmt"
var ErrDoesNotUseID3v2 error = fmt.Errorf("does not use ID3v2")
var ErrGotPadding error = fmt.Errorf("got padding")
var ErrReadMoreThanSize error = fmt.Errorf("read more bytes than size of the whole tag")
var ErrInvalidID error = fmt.Errorf("invalid identifier")

116
v2/frame.go
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@ -2,18 +2,12 @@ package v2
import (
"bytes"
"fmt"
"io"
"strings"
"unicode"
"github.com/Unbewohnte/id3ed/util"
)
var ErrGotPadding error = fmt.Errorf("got padding")
var ErrBiggerThanSize error = fmt.Errorf("frame size is bigger than size of the whole tag")
var ErrInvalidFHeaderSize error = fmt.Errorf("frame header must be 6 or 10 bytes long")
var ErrInvalidID error = fmt.Errorf("invalid identifier")
type FrameFlags struct {
TagAlterPreservation bool
FileAlterPreservation bool
@ -36,41 +30,38 @@ type Frame struct {
Contents []byte
}
// Checks if provided frame identifier is valid by
// its length and presence of invalid characters.
func isValidFrameID(frameID []byte) bool {
if len(frameID) != 3 && len(frameID) != 4 {
// Checks if given identifier is valid by specification
func isValidID(frameID string) bool {
// check if id is in ASCII table
if !util.InASCII(frameID) {
return false
}
str := strings.ToValidUTF8(string(frameID), "invalidChar")
if len(str) != 3 && len(str) != 4 {
return false
// check if id is in upper case
for _, char := range frameID {
if !unicode.IsUpper(char) {
return false
}
}
return true
}
func getV22FrameHeader(fHeaderbytes []byte) (FrameHeader, error) {
func getV22FrameHeader(fHeaderbytes []byte) FrameHeader {
var header FrameHeader
if !isValidFrameID(fHeaderbytes[0:3]) {
return FrameHeader{}, ErrInvalidID
}
header.ID = string(fHeaderbytes[0:3])
framesizeBytes := util.BytesToIntSynchsafe(fHeaderbytes[3:6])
header.Size = framesizeBytes
return header, nil
return header
}
func getV23FrameHeader(fHeaderbytes []byte) (FrameHeader, error) {
func getV23FrameHeader(fHeaderbytes []byte) FrameHeader {
var header FrameHeader
// ID
if !isValidFrameID(fHeaderbytes[0:4]) {
return FrameHeader{}, ErrInvalidID
}
header.ID = string(fHeaderbytes[0:4])
// Size
@ -119,16 +110,12 @@ func getV23FrameHeader(fHeaderbytes []byte) (FrameHeader, error) {
header.Flags = flags
return header, nil
return header
}
func getV24FrameHeader(fHeaderbytes []byte) (FrameHeader, error) {
func getV24FrameHeader(fHeaderbytes []byte) FrameHeader {
var header FrameHeader
// ID
if !isValidFrameID(fHeaderbytes[0:4]) {
return FrameHeader{}, ErrInvalidID
}
header.ID = string(fHeaderbytes[0:4])
// Size
@ -187,77 +174,68 @@ func getV24FrameHeader(fHeaderbytes []byte) (FrameHeader, error) {
header.Flags = flags
return header, nil
return header
}
// Structuralises frame header from given bytes. For versions see: constants.
func getFrameHeader(fHeaderbytes []byte, version string) (FrameHeader, error) {
// validation check
if int(len(fHeaderbytes)) != int(10) && int(len(fHeaderbytes)) != int(6) {
return FrameHeader{}, ErrInvalidFHeaderSize
}
func getFrameHeader(fHeaderbytes []byte, version string) FrameHeader {
var header FrameHeader
var err error
switch version {
case V2_2:
header, err = getV22FrameHeader(fHeaderbytes)
if err != nil {
return FrameHeader{}, err
}
header = getV22FrameHeader(fHeaderbytes)
case V2_3:
header, err = getV23FrameHeader(fHeaderbytes)
if err != nil {
return FrameHeader{}, err
}
header = getV23FrameHeader(fHeaderbytes)
case V2_4:
header, err = getV24FrameHeader(fHeaderbytes)
if err != nil {
return FrameHeader{}, err
}
header = getV24FrameHeader(fHeaderbytes)
}
return header, nil
return header
}
// Reads ID3v2.3.0 or ID3v2.4.0 frame from given frame bytes.
// Returns a blank Frame struct if encountered an error, amount of
// bytes read from io.Reader.
func readNextFrame(r io.Reader, h Header) (Frame, uint64, error) {
// Reads a frame from r.
// Returns a blank Frame struct if encountered an error.
func readNextFrame(r io.Reader, version string) (Frame, error) {
var frame Frame
var read uint64 = 0
// Frame header
headerBytes, err := util.Read(r, uint64(HEADERSIZE))
if err != nil {
return Frame{}, 0, err
var headerBytes []byte
var err error
switch version {
case V2_2:
headerBytes, err = util.Read(r, uint64(V2_2FrameHeaderSize))
if err != nil {
return Frame{}, err
}
default:
headerBytes, err = util.Read(r, uint64(V2_3FrameHeaderSize))
if err != nil {
return Frame{}, err
}
}
read += uint64(HEADERSIZE)
// check for padding and validate ID characters
if bytes.Contains(headerBytes[0:3], []byte{0}) {
return Frame{}, ErrGotPadding
}
frameHeader, err := getFrameHeader(headerBytes, h.Version)
if err == ErrGotPadding || err == ErrInvalidID {
return Frame{}, read, err
} else if err != nil {
return Frame{}, read, fmt.Errorf("could not get header of a frame: %s", err)
if !isValidID(string(headerBytes[0:3])) {
return Frame{}, ErrInvalidID
}
frameHeader := getFrameHeader(headerBytes, version)
frame.Header = frameHeader
// Contents
contents, err := util.Read(r, uint64(frameHeader.Size))
if err != nil {
return Frame{}, read, err
return Frame{}, err
}
frame.Contents = contents
read += uint64(frameHeader.Size)
return frame, read, err
return frame, nil
}
// Returns decoded string from f.Contents.

4
v2/frame_test.go
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@ -19,7 +19,7 @@ func TestReadNextFrame(t *testing.T) {
t.Errorf("%s", err)
}
firstFrame, _, err := readNextFrame(f, header)
firstFrame, err := readNextFrame(f, header.Version)
if err != nil {
t.Errorf("ReadFrame failed: %s", err)
}
@ -34,7 +34,7 @@ func TestReadNextFrame(t *testing.T) {
false, firstFrame.Header.Flags.Encrypted)
}
secondFrame, _, err := readNextFrame(f, header)
secondFrame, err := readNextFrame(f, header.Version)
if err != nil {
t.Errorf("ReadFrame failed: %s", err)
}

43
v2/read.go
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@ -15,26 +15,45 @@ func ReadV2Tag(rs io.ReadSeeker) (*ID3v2Tag, error) {
}
// collect frames
var read uint64 = 10 // because already read header
var read uint64 = 0
var frames []Frame
for {
if read > uint64(header.Size) {
if read == uint64(header.Size) {
break
} else if read > uint64(header.Size) {
// read more than required, but did not
// encouter padding, something is wrong here
return nil, ErrReadMoreThanSize
}
frame, r, err := readNextFrame(rs, header)
if err == ErrGotPadding || err == ErrBiggerThanSize || err == ErrInvalidID {
break
}
if err != nil {
return nil, fmt.Errorf("could not read frame: %s", err)
frame, err := readNextFrame(rs, header.Version)
switch err {
case nil:
case ErrGotPadding:
// expected error, just return what we`ve collected
return &ID3v2Tag{
Header: header,
Frames: frames,
}, nil
case ErrInvalidID:
// expected error, just return what we`ve collected
return &ID3v2Tag{
Header: header,
Frames: frames,
}, nil
default:
return nil, err
}
read += r
frames = append(frames, frame)
// counting how many bytes read
if header.Version == V2_2 {
read += uint64(V2_2FrameHeaderSize) + uint64(frame.Header.Size)
} else {
read += uint64(V2_3FrameHeaderSize) + uint64(frame.Header.Size)
}
}
return &ID3v2Tag{

31
v2/write.go
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@ -1,18 +1,27 @@
package v2
// func WriteFrame(frame *Frame) error {
// return nil
// }
import (
"fmt"
"io"
)
// // Writes ID3v2Tag to ws
// func (tag *ID3v2Tag) write(ws io.WriteSeeker, version string) error {
// _, err := ws.Seek(0, io.SeekStart)
// if err != nil {
// return fmt.Errorf("could not seek: %s", err)
// }
// Writes ID3v2Tag to ws
func (tag *ID3v2Tag) write(ws io.WriteSeeker) error {
_, err := ws.Seek(0, io.SeekStart)
if err != nil {
return fmt.Errorf("could not seek: %s", err)
}
// return nil
// }
// write header
ws.Write(tag.Header.toBytes())
// write frames
for _, frame := range tag.Frames {
ws.Write(frame.toBytes(tag.Header.Version))
}
return nil
}
// func (tag *ID3v2Tag) WriteToFile(f *os.File) error {
// return nil

49
v2/write_test.go
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@ -1,16 +1,41 @@
package v2
// var TESTTAG = &ID3v2Tag{
// Frames: []Frame{
// Frame{
// Header: FrameHeader{
// ID: "COMM",
// },
// Contents: []byte("comment_here"),
// },
// },
// }
// func TestWrite(t *testing.T) {
// t.Errorf("%v", TESTTAG.Header.Version)
// f, err := os.Open(filepath.Join(TESTDATAPATH, "testreadv2.mp3"))
// if err != nil {
// t.Errorf("%s", err)
// }
// defer f.Close()
// testTag, err := ReadV2Tag(f)
// if err != nil {
// t.Errorf("%s", err)
// }
// ff, err := os.OpenFile(filepath.Join(TESTDATAPATH, "testwritev2.mp3"),
// os.O_CREATE|os.O_RDWR, os.ModePerm)
// if err != nil {
// t.Errorf("%s", err)
// }
// defer ff.Close()
// err = testTag.write(ff)
// if err != nil {
// t.Errorf("%s", err)
// }
// wroteTag, err := ReadV2Tag(ff)
// if err != nil {
// t.Errorf("%s", err)
// }
// // t.Errorf("ORIGINAL: %+v", testTag)
// // t.Errorf("WRITTEN: %+v", wroteTag)
// for _, origfr := range testTag.Frames {
// t.Errorf("ORIG Fr: %+v\n", origfr)
// }
// for _, wrtfr := range wroteTag.Frames {
// t.Errorf("WRITTEN Fr: %+v\n", wrtfr)
// }
// }

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