⯄ Started working on ID3v2 frames ⯄

README.md

@@ -40,7 +40,7 @@ func main() {
     }
 
     // extract ID3v1.1 tags 
-    mp3tags, err := id3v1.GetID3v11Tags(mp3file)
+    mp3tags, err := id3v1.Getv11Tags(mp3file)
     if err != nil {
        panic(err)
     }
@@ -80,7 +80,7 @@ func main() {
             Year:     2021,
             Comment:  "Cool song",
             Track:    1,
-            Genre:    "Christian Gangsta Rap", // list of genres see "id3v1genres.go"
+            Genre:    "Christian Gangsta Rap", // for list of genres see: "./v1/genres.go"
 	}
 
     // write tags to file

util/etc.go

@@ -0,0 +1,28 @@
+package util
+
+import (
+	"bytes"
+	"encoding/binary"
+)
+
+// Returns found key (int) in provided map by value (string);
+// If key does not exist in map - returns -1
+func GetKey(mp map[int]string, givenValue string) int {
+	for key, value := range mp {
+		if value == givenValue {
+			return key
+		}
+	}
+	return -1
+}
+
+// Decodes given integer bytes into integer
+func BytesToInt(gBytes []byte) (int64, error) {
+	buff := bytes.NewBuffer(gBytes)
+	integer, err := binary.ReadVarint(buff)
+	if err != nil {
+		return 0, err
+	}
+	buff = nil
+	return integer, nil
+}

util/read.go

@@ -0,0 +1,37 @@
+package util
+
+import (
+	"fmt"
+	"io"
+)
+
+// Shortcut function to read n bytes from reader. The general idea peeked from here: https://github.com/dhowden/tag/blob/master/util.go
+func Read(rs io.Reader, n uint64) ([]byte, error) {
+	read := make([]byte, n)
+	_, err := rs.Read(read)
+	if err != nil {
+		return nil, fmt.Errorf("could not read from reader: %s", err)
+	}
+
+	return read, nil
+}
+
+// Shortcut function to read n bytes and convert them into string.
+// If encountered zero-byte - converts to string only previously read bytes
+func ReadToString(rs io.Reader, n int) (string, error) {
+	read := make([]byte, n)
+	_, err := rs.Read(read)
+	if err != nil {
+		return "", fmt.Errorf("could not read from reader: %s", err)
+	}
+
+	var readString string
+	for _, b := range read {
+		if b == 0 {
+			break
+		}
+		readString += string(b)
+	}
+
+	return readString, nil
+}

util/util.go

@@ -1,90 +0,0 @@
-package util
-
-import (
-	"bytes"
-	"encoding/binary"
-	"fmt"
-	"io"
-)
-
-// Shortcut function to read n bytes from reader. Peeked from here: https://github.com/dhowden/tag/blob/master/util.go
-func Read(rs io.Reader, n int) ([]byte, error) {
-	read := make([]byte, n)
-	_, err := rs.Read(read)
-	if err != nil {
-		return nil, fmt.Errorf("could not read from reader: %s", err)
-	}
-
-	return read, nil
-}
-
-// Shortcut function to read n bytes and convert them into string.
-// If encountered zero-byte - converts to string only previously read bytes
-func ReadToString(rs io.Reader, n int) (string, error) {
-	read := make([]byte, n)
-	_, err := rs.Read(read)
-	if err != nil {
-		return "", fmt.Errorf("could not read from reader: %s", err)
-	}
-
-	var readString string
-	for _, b := range read {
-		if b == 0 {
-			break
-		}
-		readString += string(b)
-	}
-
-	return readString, nil
-}
-
-// Writes data to wr, if len(data) is less than lenNeeded - adds null bytes until written lenNeeded bytes
-func WriteToExtent(wr io.Writer, data []byte, lenNeeded int) error {
-	if len(data) > lenNeeded {
-		return fmt.Errorf("length of given data bytes is bigger than length needed")
-	}
-
-	buff := new(bytes.Buffer)
-	for i := 0; i < lenNeeded; i++ {
-		if i < len(data) {
-			err := buff.WriteByte(data[i])
-			if err != nil {
-				return err
-			}
-		} else {
-			err := buff.WriteByte(0)
-			if err != nil {
-				return err
-			}
-		}
-	}
-
-	_, err := wr.Write(buff.Bytes())
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-// Returns found key (int) in provided map by value (string);
-// If key does not exist in map - returns -1
-func GetKey(mp map[int]string, givenValue string) int {
-	for key, value := range mp {
-		if value == givenValue {
-			return key
-		}
-	}
-	return -1
-}
-
-// Decodes given integer bytes into integer
-func BytesToInt(gBytes []byte) (int64, error) {
-	buff := bytes.NewBuffer(gBytes)
-	integer, err := binary.ReadVarint(buff)
-	if err != nil {
-		return 0, err
-	}
-	buff = nil
-	return integer, nil
-}

util/write.go

@@ -0,0 +1,36 @@
+package util
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+)
+
+// Writes data to wr, if len(data) is less than lenNeeded - adds null bytes until written lenNeeded bytes
+func WriteToExtent(wr io.Writer, data []byte, lenNeeded int) error {
+	if len(data) > lenNeeded {
+		return fmt.Errorf("length of given data bytes is bigger than length needed")
+	}
+
+	buff := new(bytes.Buffer)
+	for i := 0; i < lenNeeded; i++ {
+		if i < len(data) {
+			err := buff.WriteByte(data[i])
+			if err != nil {
+				return err
+			}
+		} else {
+			err := buff.WriteByte(0)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	_, err := wr.Write(buff.Bytes())
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

v1/id3v10.go

@@ -23,7 +23,7 @@ type ID3v1Tags struct {
 }
 
 // Retrieves ID3v1 field values of provided io.ReadSeeker (usually a file)
-func GetID3v1Tags(rs io.ReadSeeker) (*ID3v1Tags, error) {
+func Getv1Tags(rs io.ReadSeeker) (*ID3v1Tags, error) {
 	// set reader to the last 128 bytes
 	_, err := rs.Seek(-int64(ID3v1SIZE), io.SeekEnd)
 	if err != nil {

v1/id3v10_test.go

@@ -17,12 +17,12 @@ var TESTv1TAGS = &ID3v1Tags{
 	Genre:    "Blues",
 }
 
-func TestGetID3v1Tags(t *testing.T) {
+func TestGetv1Tags(t *testing.T) {
 	testfile, err := os.OpenFile(filepath.Join(TESTDATAPATH, "testreadv1.mp3"), os.O_CREATE|os.O_RDONLY, os.ModePerm)
 	if err != nil {
 		t.Errorf("could not open file for testing: %s", err)
 	}
-	tags, err := GetID3v1Tags(testfile)
+	tags, err := Getv1Tags(testfile)
 	if err != nil {
 		t.Errorf("GetID3v1Tags failed: %s", err)
 	}
@@ -32,7 +32,7 @@ func TestGetID3v1Tags(t *testing.T) {
 	}
 }
 
-func TestWriteID3v1Tags(t *testing.T) {
+func TestWritev1Tags(t *testing.T) {
 	f, err := os.OpenFile(filepath.Join(TESTDATAPATH, "testwritev1.mp3"), os.O_CREATE|os.O_RDWR, os.ModePerm)
 	if err != nil {
 		t.Errorf("%s", err)
@@ -48,7 +48,7 @@ func TestWriteID3v1Tags(t *testing.T) {
 	}
 
 	// reading tags
-	readTags, err := GetID3v1Tags(f)
+	readTags, err := Getv1Tags(f)
 	if err != nil {
 		t.Errorf("%s", err)
 	}

v1/id3v11.go

@@ -22,7 +22,7 @@ type ID3v11Tags struct {
 }
 
 // Retrieves ID3v1.1 field values of provided io.ReadSeeker
-func GetID3v11Tags(rs io.ReadSeeker) (*ID3v11Tags, error) {
+func Getv11Tags(rs io.ReadSeeker) (*ID3v11Tags, error) {
 	// set reader to the last 128 bytes
 	_, err := rs.Seek(-int64(ID3v1SIZE), io.SeekEnd)
 	if err != nil {

v1/id3v11_test.go

@@ -22,7 +22,7 @@ func TestGetID3v11Tags(t *testing.T) {
 	if err != nil {
 		t.Errorf("could not open file for testing: %s", err)
 	}
-	mp3tags, err := GetID3v11Tags(testfile)
+	mp3tags, err := Getv11Tags(testfile)
 	if err != nil {
 		t.Errorf("GetID3v11Tags failed: %s", err)
 	}
@@ -52,7 +52,7 @@ func TestWriteID3v11Tags(t *testing.T) {
 		t.Errorf("WriteID3v1Tags failed: %s", err)
 	}
 
-	readTags, err := GetID3v11Tags(f)
+	readTags, err := Getv11Tags(f)
 	if err != nil {
 		t.Errorf("%s", err)
 	}

v2/constants.go

@@ -1,6 +1,6 @@
 package v2
 
 //ID3v2
-const ID3v2IDENTIFIER string = "ID3"
-const ID3v2HEADERSIZE int = 10     // bytes
-const ID3v2MAXSIZE int = 268435456 // bytes (256 MB)
+const HEADERIDENTIFIER string = "ID3"
+const HEADERSIZE int = 10           // bytes
+const HEADERMAXSIZE int = 268435456 // bytes (256 MB)

v2/frame.go

@@ -0,0 +1,59 @@
+package v2
+
+import (
+	"io"
+
+	"github.com/Unbewohnte/id3ed/util"
+)
+
+////////////////////////////////////////////////////////////////////////////
+//(ᗜˬᗜ)~⭐//Under construction//Please don`t use it in this verison//(ᗜ‸ᗜ)///
+////////////////////////////////////////////////////////////////////////////
+
+type FrameHeader struct {
+	Identifier string
+	FrameSize  int64
+}
+
+type Frame struct {
+	Header   *FrameHeader
+	Contents string
+}
+
+// NOT TESTED !
+func Readv2Frame(rs io.Reader) (*Frame, error) {
+	var frameHeader *FrameHeader
+	var frame Frame
+
+	identifier, err := util.ReadToString(rs, 3)
+	if err != nil {
+		return nil, err
+	}
+	frameHeader.Identifier = identifier
+
+	framesizeBytes, err := util.Read(rs, 3)
+	if err != nil {
+		return nil, err
+	}
+
+	framesize, err := util.BytesToInt(framesizeBytes)
+	if err != nil {
+		return nil, err
+	}
+
+	frameHeader.FrameSize = framesize
+
+	frameContents, err := util.ReadToString(rs, int(framesize))
+	if err != nil {
+		return nil, err
+	}
+
+	frame.Header = frameHeader
+	frame.Contents = frameContents
+
+	return &frame, nil
+}
+
+// func ReadFrame(rs io.Reader, version string) error {
+// 	return nil
+// }

v2/frame_test.go

@@ -0,0 +1,16 @@
+package v2
+
+// func TestReadFrame(t *testing.T) {
+// 	f, err := os.Open(filepath.Join(TESTDATAPATH, "testreadv2.mp3"))
+// 	if err != nil {
+// 		t.Errorf("%s", err)
+// 	}
+
+// 	// read right after header`s bytes
+// 	f.Seek(int64(HEADERSIZE), io.SeekStart)
+
+// 	_, err = Readv2Frame(f)
+// 	if err != nil {
+// 		t.Errorf("ReadFrame failed: %s", err)
+// 	}
+// }

v2/header.go

@@ -1,9 +1,5 @@
 package v2
 
-//////////////////////////////////////
-//(ᗜˬᗜ)~⭐//Under construction//(ᗜ‸ᗜ)//
-//////////////////////////////////////
-
 import (
 	"bytes"
 	"fmt"
@@ -33,7 +29,7 @@ func GetHeader(rs io.ReadSeeker) (*Header, error) {
 		return nil, err
 	}
 	// check if ID3v2 is used
-	if !bytes.Equal([]byte(ID3v2IDENTIFIER), identifier) {
+	if !bytes.Equal([]byte(HEADERIDENTIFIER), identifier) {
 		return nil, fmt.Errorf("no ID3v2 identifier found")
 	}
 	header.Identifier = string(identifier)