From 96fc9cb1110636d98bf36cf02c33daf9c7b3d3dd Mon Sep 17 00:00:00 2001
From: Unbewohnte <unbewohnte@gmail.com>
Date: Fri, 23 Jul 2021 10:33:55 +0300
Subject: [PATCH] =?UTF-8?q?=E2=9A=AA=20Fixed=20a=20bug=20in=20writing=20en?=
 =?UTF-8?q?hanced=20tag,=20added=20creating=20functions=20to=20v2=20?=
 =?UTF-8?q?=E2=9A=AA?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 testData/testwritev1.mp3 | Bin 844 -> 279 bytes
 v1/read.go               |  15 +------
 v1/read_test.go          |   1 +
 v1/tag.go                |   8 ++++
 v1/write.go              |  13 +++++-
 v1/write_test.go         |   1 -
 v2/frame.go              |  90 ++++++++++++++++++++++++++++++++-------
 v2/frame_test.go         |  43 +++++++++++++------
 v2/header.go             |  29 +++++++++++++
 v2/read.go               |   4 +-
 v2/v2tag.go              |  16 ++++++-
 v2/v2tag_test.go         |  34 +++++++++++++++
 v2/write.go              |  12 ++++--
 13 files changed, 215 insertions(+), 51 deletions(-)
 create mode 100644 v2/v2tag_test.go

diff --git a/testData/testwritev1.mp3 b/testData/testwritev1.mp3
index 477ef56042669dbb8d94db531746a2c4dca9dafb..2831d265bd7b8d0cd71f64a760c70e462e120ba0 100644
GIT binary patch
delta 138
zcmXAdu?+%23<OUf5Ns76(Et??(E!=ufJ4T-E%3>IkkSGY0ZmZ>)$k7^?W{EK#jATP
z@8|0{9QqRn1A}v@)JYHyGEuIiWe1+u6ke1)qo2^?S;O;QvxnaPE&TUk#fb=XWRps^
Wf*3dqGu!p1@z_ScNJ{DX>Ea8u)-1vR

literal 844
zcmXTU&rMZGNi0cJ$Ve?p<toWYEKw-W&r2xbN=j8I$uCXLNKN753UPGT_H*=gWgrtc
z1_cF$cm{`%qutR52%JJgLw(87O{|_#9})_wArXfqsl_G5`FZKsJp+<WEGo$?F2N=b
bmd!~j&BZ3kU~Xj208){hpPQSSht&W8+uAkT

diff --git a/v1/read.go b/v1/read.go
index c4748f1..0d3bfdb 100644
--- a/v1/read.go
+++ b/v1/read.go
@@ -41,6 +41,7 @@ func containsEnhancedTAG(rs io.ReadSeeker) bool {
 		return false
 	}
 	if !bytes.Equal(identifier, []byte(ENHANCEDIDENTIFIER)) {
+		fmt.Printf("UWAH: %s ---- %s\n", identifier, ENHANCEDIDENTIFIER)
 		return false
 	}
 
@@ -88,19 +89,7 @@ func readEnhancedTag(rs io.ReadSeeker) (EnhancedID3v1Tag, error) {
 		return enhanced, err
 	}
 
-	var speed string
-	switch speedByte[0] {
-	case 0:
-		speed = "Unset"
-	case 1:
-		speed = "Slow"
-	case 2:
-		speed = "Medium"
-	case 3:
-		speed = "Fast"
-	case 4:
-		speed = "Hardcore"
-	}
+	var speed string = EnhancedSpeed[int(speedByte[0])]
 	enhanced.Speed = speed
 
 	// genre
diff --git a/v1/read_test.go b/v1/read_test.go
index 5aa361d..267e2e0 100644
--- a/v1/read_test.go
+++ b/v1/read_test.go
@@ -18,6 +18,7 @@ var TESTv1TAG = &ID3v1Tag{
 		Artist:   "ARRRTIST",
 		Album:    "ALLLLBUUUM",
 		SongName: "NAME",
+		Speed:    EnhancedSpeed[2],
 	},
 }
 
diff --git a/v1/tag.go b/v1/tag.go
index 39ec676..773c0b1 100644
--- a/v1/tag.go
+++ b/v1/tag.go
@@ -26,3 +26,11 @@ type EnhancedID3v1Tag struct {
 	StartTime string
 	EndTime   string
 }
+
+var EnhancedSpeed = map[int]string{
+	0: "Unset",
+	1: "Slow",
+	2: "Medium",
+	3: "Fast",
+	4: "Hardcore",
+}
diff --git a/v1/write.go b/v1/write.go
index a6d0e44..9de8fad 100644
--- a/v1/write.go
+++ b/v1/write.go
@@ -45,7 +45,8 @@ func (tag *ID3v1Tag) write(dst io.WriteSeeker) error {
 		}
 
 		// Speed
-		_, err = dst.Write([]byte(tag.EnhancedTag.Speed))
+		speed := util.GetKey(EnhancedSpeed, tag.EnhancedTag.Speed)
+		_, err = dst.Write([]byte{byte(speed)})
 		if err != nil {
 			return err
 		}
@@ -162,8 +163,10 @@ func (tag *ID3v1Tag) WriteToFile(f *os.File) error {
 	switch {
 
 	case containsEnhancedTAG(f) && containsTAG(f):
+		fmt.Println("HEA1")
+
 		// remove both
-		err = f.Truncate(filesize - int64(TAGSIZE) - int64(ENHANCEDSIZE))
+		err = f.Truncate(filesize - int64(TAGSIZE+ENHANCEDSIZE))
 		if err != nil {
 			return fmt.Errorf("could not truncate file %s", err)
 		}
@@ -174,6 +177,8 @@ func (tag *ID3v1Tag) WriteToFile(f *os.File) error {
 		}
 
 	case containsEnhancedTAG(f) && !containsTAG(f):
+		fmt.Println("HEA2")
+
 		// remove enhanced tag, replace with new
 		err = f.Truncate(filesize - int64(ENHANCEDSIZE))
 		if err != nil {
@@ -186,6 +191,8 @@ func (tag *ID3v1Tag) WriteToFile(f *os.File) error {
 		}
 
 	case !containsEnhancedTAG(f) && containsTAG(f):
+		fmt.Println("HEA3")
+
 		// remove regular one, replace with new
 		err = f.Truncate(filesize - int64(TAGSIZE))
 		if err != nil {
@@ -198,6 +205,8 @@ func (tag *ID3v1Tag) WriteToFile(f *os.File) error {
 		}
 
 	case !containsEnhancedTAG(f) && !containsTAG(f):
+		fmt.Println("HEA4")
+
 		// no existing TAGs, simply write what we have
 		err := tag.write(f)
 		if err != nil {
diff --git a/v1/write_test.go b/v1/write_test.go
index 8e6c901..955bd62 100644
--- a/v1/write_test.go
+++ b/v1/write_test.go
@@ -20,5 +20,4 @@ func TestWriteID3v1ToFile(t *testing.T) {
 	if err != nil {
 		t.Errorf("WriteID3v1ToFile failed: %s", err)
 	}
-
 }
diff --git a/v2/frame.go b/v2/frame.go
index 88bd8f9..c550fd8 100644
--- a/v2/frame.go
+++ b/v2/frame.go
@@ -2,6 +2,7 @@ package v2
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"unicode"
 
@@ -20,9 +21,9 @@ type FrameFlags struct {
 }
 
 type FrameHeader struct {
-	ID    string
-	Size  uint32
-	Flags FrameFlags
+	id    string
+	size  uint32
+	flags FrameFlags
 }
 
 type Frame struct {
@@ -30,6 +31,20 @@ type Frame struct {
 	Contents []byte
 }
 
+// getters
+
+func (fh *FrameHeader) ID() string {
+	return fh.id
+}
+
+func (fh *FrameHeader) Size() uint32 {
+	return fh.size
+}
+
+func (fh *FrameHeader) Flags() FrameFlags {
+	return fh.flags
+}
+
 // Checks if given identifier is valid by specification
 func isValidID(frameID string) bool {
 	// check if id is in ASCII table
@@ -50,10 +65,10 @@ func isValidID(frameID string) bool {
 func getV22FrameHeader(fHeaderbytes []byte) FrameHeader {
 	var header FrameHeader
 
-	header.ID = string(fHeaderbytes[0:3])
+	header.id = string(fHeaderbytes[0:3])
 
 	framesizeBytes := util.BytesToIntSynchsafe(fHeaderbytes[3:6])
-	header.Size = framesizeBytes
+	header.size = framesizeBytes
 
 	return header
 }
@@ -62,14 +77,14 @@ func getV23FrameHeader(fHeaderbytes []byte) FrameHeader {
 	var header FrameHeader
 
 	// ID
-	header.ID = string(fHeaderbytes[0:4])
+	header.id = string(fHeaderbytes[0:4])
 
 	// Size
 	framesizeBytes := fHeaderbytes[4:8]
 
 	framesize := util.BytesToIntSynchsafe(framesizeBytes)
 
-	header.Size = framesize
+	header.size = framesize
 
 	// Flags
 	frameFlags1 := fHeaderbytes[8]
@@ -108,7 +123,7 @@ func getV23FrameHeader(fHeaderbytes []byte) FrameHeader {
 		flags.InGroup = false
 	}
 
-	header.Flags = flags
+	header.flags = flags
 
 	return header
 }
@@ -116,14 +131,14 @@ func getV23FrameHeader(fHeaderbytes []byte) FrameHeader {
 func getV24FrameHeader(fHeaderbytes []byte) FrameHeader {
 	var header FrameHeader
 
-	header.ID = string(fHeaderbytes[0:4])
+	header.id = string(fHeaderbytes[0:4])
 
 	// Size
 	framesizeBytes := fHeaderbytes[4:8]
 
 	framesize := util.BytesToIntSynchsafe(framesizeBytes)
 
-	header.Size = framesize
+	header.size = framesize
 
 	// Flags
 	frameFlags1 := fHeaderbytes[8]
@@ -172,7 +187,7 @@ func getV24FrameHeader(fHeaderbytes []byte) FrameHeader {
 		flags.HasDataLengthIndicator = false
 	}
 
-	header.Flags = flags
+	header.flags = flags
 
 	return header
 }
@@ -229,7 +244,7 @@ func readNextFrame(r io.Reader, version string) (Frame, error) {
 	frame.Header = frameHeader
 
 	// Contents
-	contents, err := util.Read(r, uint64(frameHeader.Size))
+	contents, err := util.Read(r, uint64(frameHeader.size))
 	if err != nil {
 		return Frame{}, err
 	}
@@ -309,17 +324,25 @@ func frameFlagsToBytes(ff FrameFlags, version string) []byte {
 }
 
 // Converts frame to ready-to-write bytes
-func (f *Frame) toBytes(version string) []byte {
+func (f *Frame) toBytes() []byte {
 	buff := new(bytes.Buffer)
 
 	// identifier
-	buff.Write([]byte(f.Header.ID))
+	buff.Write([]byte(f.Header.id))
 
 	// size
-	buff.Write(util.IntToBytesSynchsafe(f.Header.Size))
+	buff.Write(util.IntToBytesSynchsafe(f.Header.size))
 
 	// flags
-	flagBytes := frameFlagsToBytes(f.Header.Flags, version)
+
+	var version string
+	if len(f.Header.id) == 4 {
+		version = V2_4
+	} else {
+		version = V2_2
+	}
+
+	flagBytes := frameFlagsToBytes(f.Header.flags, version)
 	if flagBytes != nil {
 		buff.Write(flagBytes)
 	}
@@ -329,3 +352,38 @@ func (f *Frame) toBytes(version string) []byte {
 
 	return buff.Bytes()
 }
+
+// Constructs a new frame from provided information.
+// isTextFrame must be set to true if gContents are not a binary data.
+// Returns an error if provided id`s len is neither 3 or 4
+func NewFrame(id string, gContents []byte, isTextframe bool) (*Frame, error) {
+	if len(id) != 3 && len(id) != 4 {
+		return nil, fmt.Errorf("frame identifier`s length must be 3 or 4")
+	}
+
+	var fheader FrameHeader
+
+	// contents
+	var contents []byte
+	if isTextframe {
+		// add UTF-8 encoding byte
+		contents = []byte{util.EncodingUTF8}
+		contents = append(contents, gContents...)
+	} else {
+		contents = gContents
+	}
+
+	// id
+	fheader.id = id
+
+	// size
+	fheader.size = uint32(len(contents))
+
+	// flags (all false)
+	fheader.flags = FrameFlags{}
+
+	return &Frame{
+		Header:   fheader,
+		Contents: contents,
+	}, nil
+}
diff --git a/v2/frame_test.go b/v2/frame_test.go
index 6ba9fd2..27a1770 100644
--- a/v2/frame_test.go
+++ b/v2/frame_test.go
@@ -24,14 +24,14 @@ func TestReadNextFrame(t *testing.T) {
 		t.Errorf("ReadFrame failed: %s", err)
 	}
 
-	if firstFrame.Header.ID != "TRCK" {
+	if firstFrame.Header.ID() != "TRCK" {
 		t.Errorf("GetFrame failed: expected ID %s; got %s",
-			"TRCK", firstFrame.Header.ID)
+			"TRCK", firstFrame.Header.ID())
 	}
 
-	if firstFrame.Header.Flags.Encrypted != false {
+	if firstFrame.Header.Flags().Encrypted != false {
 		t.Errorf("ReadFrame failed: expected compressed flag to be %v; got %v",
-			false, firstFrame.Header.Flags.Encrypted)
+			false, firstFrame.Header.Flags().Encrypted)
 	}
 
 	secondFrame, err := readNextFrame(f, header.Version())
@@ -39,9 +39,9 @@ func TestReadNextFrame(t *testing.T) {
 		t.Errorf("ReadFrame failed: %s", err)
 	}
 
-	if secondFrame.Header.ID != "TDRC" {
+	if secondFrame.Header.ID() != "TDRC" {
 		t.Errorf("ReadFrame failed: expected ID %s; got %s",
-			"TDRC", secondFrame.Header.ID)
+			"TDRC", secondFrame.Header.ID())
 	}
 
 	if util.ToStringLossy(secondFrame.Contents) != "2006" {
@@ -72,14 +72,14 @@ func TestFrameFlagsToBytes(t *testing.T) {
 func TestFrameToBytes(t *testing.T) {
 	testframe := Frame{
 		Header: FrameHeader{
-			ID:    "TEST",
-			Flags: FrameFlags{}, // all false
-			Size:  4,
+			id:    "TEST",
+			flags: FrameFlags{}, // all false
+			size:  4,
 		},
 		Contents: []byte{util.EncodingUTF8, 60, 60, 60}, // 60 == <
 	}
 
-	frameBytes := testframe.toBytes(V2_4)
+	frameBytes := testframe.toBytes()
 
 	// t.Errorf("%+v", frameBytes)
 	// 84 69 83 84 0 0 0 4 0 0 3 60 60 60
@@ -90,9 +90,9 @@ func TestFrameToBytes(t *testing.T) {
 	// header - 4 + 4 + 2 = 10 bytes (success)
 	// 3 60 60 60 - contents
 
-	if len(frameBytes)-int(testframe.Header.Size) != HEADERSIZE {
+	if len(frameBytes)-int(testframe.Header.Size()) != HEADERSIZE {
 		t.Errorf("FrameToBytes failed: expected header size to be %d; got %d",
-			HEADERSIZE, len(frameBytes)-int(testframe.Header.Size))
+			HEADERSIZE, len(frameBytes)-int(testframe.Header.Size()))
 	}
 
 	if util.DecodeText(frameBytes[10:]) != "<<<" {
@@ -100,3 +100,22 @@ func TestFrameToBytes(t *testing.T) {
 			testframe.Contents, frameBytes[10:])
 	}
 }
+
+func TestNewFrame(t *testing.T) {
+	gotFrame, err := NewFrame("TMRK", []byte("Very cool"), true)
+	if err != nil {
+		t.Errorf("CreateFrame failed: %s", err)
+	}
+
+	// check for encoding byte
+	if gotFrame.Contents[0] != util.EncodingUTF8 {
+		t.Errorf("CreateFrame failed: contents are expected to have an encoding byte %v; got %v",
+			util.EncodingUTF8, gotFrame.Contents[0])
+	}
+
+	if gotFrame.Header.Size() != uint32(len(gotFrame.Contents)) {
+		t.Errorf("CreateFrame failed: expected size to be %d; got %d",
+			len(gotFrame.Contents), gotFrame.Header.Size())
+	}
+
+}
diff --git a/v2/header.go b/v2/header.go
index 9c19171..fdaab6d 100644
--- a/v2/header.go
+++ b/v2/header.go
@@ -452,3 +452,32 @@ func (h *Header) toBytes() []byte {
 
 	return buff.Bytes()
 }
+
+// Creates an appropriate header based on
+// provided frames
+func newHeader(frames []Frame) *Header {
+	var header Header
+
+	// flags (all false)
+	header.flags = HeaderFlags{}
+
+	// version
+	if len(frames[0].Header.ID()) == 4 {
+		header.version = V2_4
+	} else {
+		header.version = V2_2
+	}
+
+	// size
+	var framesSize uint32 = 0
+	for _, frame := range frames {
+		framesSize += uint32(len(frame.toBytes()))
+	}
+
+	header.size = framesSize
+
+	// extended header (not used)
+	header.extendedHeader = ExtendedHeader{}
+
+	return &header
+}
diff --git a/v2/read.go b/v2/read.go
index 7df9465..82f95f2 100644
--- a/v2/read.go
+++ b/v2/read.go
@@ -50,9 +50,9 @@ func ReadV2Tag(rs io.ReadSeeker) (*ID3v2Tag, error) {
 
 		// counting how many bytes read
 		if header.Version() == V2_2 {
-			read += uint64(V2_2FrameHeaderSize) + uint64(frame.Header.Size)
+			read += uint64(V2_2FrameHeaderSize) + uint64(frame.Header.Size())
 		} else {
-			read += uint64(V2_3FrameHeaderSize) + uint64(frame.Header.Size)
+			read += uint64(V2_3FrameHeaderSize) + uint64(frame.Header.Size())
 		}
 	}
 
diff --git a/v2/v2tag.go b/v2/v2tag.go
index 3bae1ee..300ca11 100644
--- a/v2/v2tag.go
+++ b/v2/v2tag.go
@@ -7,11 +7,23 @@ type ID3v2Tag struct {
 	Frames []Frame
 }
 
+// Creates a new v2 tag from given created frames
+func NewTAG(frames []Frame) *ID3v2Tag {
+	var newtag ID3v2Tag
+
+	header := newHeader(frames)
+
+	newtag.Header = *header
+	newtag.Frames = frames
+
+	return &newtag
+}
+
 // Searches for frame with the same identifier as id in tag,
 // returns &it if found
 func (tag *ID3v2Tag) GetFrame(id string) *Frame {
 	for _, frame := range tag.Frames {
-		if strings.EqualFold(frame.Header.ID, id) {
+		if strings.EqualFold(frame.Header.ID(), id) {
 			return &frame
 		}
 	}
@@ -21,7 +33,7 @@ func (tag *ID3v2Tag) GetFrame(id string) *Frame {
 // Checks if a frame with given id exists
 func (tag *ID3v2Tag) FrameExists(id string) bool {
 	for _, frame := range tag.Frames {
-		if strings.EqualFold(frame.Header.ID, id) {
+		if strings.EqualFold(frame.Header.ID(), id) {
 			return true
 		}
 	}
diff --git a/v2/v2tag_test.go b/v2/v2tag_test.go
new file mode 100644
index 0000000..cbc3461
--- /dev/null
+++ b/v2/v2tag_test.go
@@ -0,0 +1,34 @@
+package v2
+
+import "testing"
+
+func TestNewTAG(t *testing.T) {
+	frame1, err := NewFrame("TTST", []byte("TEST text FRAME (ᗜˬᗜ)"), true)
+	if err != nil {
+		t.Errorf("%s", err)
+	}
+	frame2, err := NewFrame("BNRY", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 255}, false)
+	if err != nil {
+		t.Errorf("%s", err)
+	}
+
+	newtag := NewTAG([]Frame{*frame1, *frame2})
+
+	if newtag.Header.Version() != V2_4 {
+		t.Errorf("NewTAG failed: expected version to be %s; got %s",
+			V2_4, newtag.Header.Version())
+	}
+
+	var size uint32 = 0
+	for _, frame := range newtag.Frames {
+		size += uint32(len(frame.toBytes()))
+	}
+
+	if newtag.Header.Size() != size {
+		t.Errorf("NewTAG failed: expected size to be %d; got %d",
+			size, newtag.Header.Size())
+	}
+
+	// t.Errorf("%+v", newtag)
+
+}
diff --git a/v2/write.go b/v2/write.go
index 4934680..652c5de 100644
--- a/v2/write.go
+++ b/v2/write.go
@@ -1,6 +1,6 @@
 package v2
 
-// Writes ID3v2Tag to ws
+// // Writes ID3v2Tag to ws
 // func (tag *ID3v2Tag) write(ws io.WriteSeeker) error {
 // 	_, err := ws.Seek(0, io.SeekStart)
 // 	if err != nil {
@@ -8,11 +8,17 @@ package v2
 // 	}
 
 // 	// write header
-// 	ws.Write(tag.Header.toBytes())
+// 	_, err = ws.Write(tag.Header.toBytes())
+// 	if err != nil {
+// 		return fmt.Errorf("could not write to writer: %s", err)
+// 	}
 
 // 	// write frames
 // 	for _, frame := range tag.Frames {
-// 		ws.Write(frame.toBytes(tag.Header.Version()))
+// 		_, err = ws.Write(frame.toBytes())
+// 		if err != nil {
+// 			return fmt.Errorf("could not write to writer: %s", err)
+// 		}
 // 	}
 
 // 	return nil