⪦ Error fixing and small improvements ⪧

README.md

@@ -12,12 +12,12 @@
 
 To download package source:
 ```
-go get github.com/Unbewohnte/id3ed
+go get github.com/Unbewohnte/id3ed/...
 ```
 
 To compile package:
 ```
-go install github.com/Unbewohnte/id3ed
+go install github.com/Unbewohnte/id3ed/...
 ```
 
 ---

v2/frame.go

@@ -21,17 +21,19 @@ type Frame struct {
 	Contents string
 }
 
-// NOT TESTED ! Reads v2.3 | v2.4 frame
-func ReadFrame(rs io.Reader) (*Frame, error) {
+// Reads ID3v2.3.0 or ID3v2.4.0 frame
+func ReadFrame(rs io.Reader, version uint) (*Frame, error) {
 	var frameHeader FrameHeader
 	var frame Frame
 
+	// ID
 	identifier, err := util.ReadToString(rs, 4)
 	if err != nil {
 		return nil, err
 	}
 	frameHeader.ID = identifier
 
+	// Size
 	framesizeBytes, err := util.Read(rs, 4)
 	if err != nil {
 		return nil, err
@@ -44,18 +46,20 @@ func ReadFrame(rs io.Reader) (*Frame, error) {
 
 	frameHeader.FrameSize = framesize
 
+	// Flags
 	frameFlagsBytes, err := util.Read(rs, 2)
 	if err != nil {
 		return nil, err
 	}
 
-	// STILL NOT IMPLEMENTED FLAG HANDLING  !
 	frameFlags, err := util.BytesToInt(frameFlagsBytes)
 	if err != nil {
 		return nil, err
 	}
+
 	frameHeader.Flags = int(frameFlags)
 
+	// Body
 	frameContents, err := util.Read(rs, uint64(framesize))
 	if err != nil {
 		return nil, err

v2/frame_test.go

@@ -16,7 +16,7 @@ func TestReadFrame(t *testing.T) {
 	// read right after header`s bytes
 	f.Seek(int64(HEADERSIZE), io.SeekStart)
 
-	firstFrame, err := ReadFrame(f)
+	firstFrame, err := ReadFrame(f, 24)
 	if err != nil {
 		t.Errorf("ReadFrame failed: %s", err)
 	}

v2/header.go

@@ -4,20 +4,28 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"strconv"
 
 	"github.com/Unbewohnte/id3ed/util"
 )
 
+type HeaderFlags struct {
+	Unsynchronisated  bool
+	HasExtendedHeader bool
+	Experimental      bool
+	FooterPresent     bool
+}
+
 // ID3v2.x header structure
 type Header struct {
 	Identifier string
-	Version          string
-	Unsynchronisated bool
-	Compressed       bool
+	Flags      HeaderFlags
+	Version    uint
+
 	Size int64 // size of the whole tag - 10 header bytes
 }
 
-// Reads and structuralises ID3v2 header
+// Reads and structuralises ID3v2.3.0 or ID3v2.4.0 header
 func GetHeader(rs io.ReadSeeker) (*Header, error) {
 	var header Header
 
@@ -51,23 +59,63 @@ func GetHeader(rs io.ReadSeeker) (*Header, error) {
 	if err != nil {
 		return nil, err
 	}
-	header.Version = fmt.Sprintf("%d%d", -majorVersion, revisionNumber)
+
+	version, err := strconv.Atoi(fmt.Sprintf("%d%d", majorVersion, revisionNumber))
+	if err != nil {
+		return nil, err
+	}
+	header.Version = uint(version)
 
 	// flags
 	flags, err := util.Read(rs, 1)
 	if err != nil {
 		return nil, err
 	}
-	bits := fmt.Sprintf("%08b", flags) // 1 byte is 8 bits
-	if bits[0] == 1 {
-		header.Unsynchronisated = true
+
+	flagBits := fmt.Sprintf("%08b", flags) // 1 byte is 8 bits
+
+	// v3.0 and v4.0 have different amount of flags
+	switch version {
+	case 30:
+		if flagBits[0] == 1 {
+			header.Flags.Unsynchronisated = true
 		} else {
-		header.Unsynchronisated = false
+			header.Flags.Unsynchronisated = false
 		}
-	if bits[1] == 1 {
-		header.Compressed = true
+		if flagBits[1] == 1 {
+			header.Flags.HasExtendedHeader = true
 		} else {
-		header.Compressed = false
+			header.Flags.HasExtendedHeader = false
+		}
+		if flagBits[2] == 1 {
+			header.Flags.Experimental = true
+		} else {
+			header.Flags.Experimental = false
+		}
+		// always false, because ID3v2.3.0 does not support footers
+		header.Flags.FooterPresent = false
+
+	case 40:
+		if flagBits[0] == 1 {
+			header.Flags.Unsynchronisated = true
+		} else {
+			header.Flags.Unsynchronisated = false
+		}
+		if flagBits[1] == 1 {
+			header.Flags.HasExtendedHeader = true
+		} else {
+			header.Flags.HasExtendedHeader = false
+		}
+		if flagBits[2] == 1 {
+			header.Flags.Experimental = true
+		} else {
+			header.Flags.Experimental = false
+		}
+		if flagBits[3] == 1 {
+			header.Flags.FooterPresent = true
+		} else {
+			header.Flags.FooterPresent = false
+		}
 	}
 
 	// size

v2/header_test.go

@@ -23,12 +23,12 @@ func TestGetHeader(t *testing.T) {
 		t.Errorf("GetHeader failed: expected identifier %s; got %s", "ID3", header.Identifier)
 	}
 
-	if header.Compressed != false {
-		t.Errorf("GetHeader failed: expected flag %v; got %v", false, header.Compressed)
+	if header.Flags.HasExtendedHeader != false {
+		t.Errorf("GetHeader failed: expected flag %v; got %v", false, header.Flags.HasExtendedHeader)
 	}
 
-	if header.Unsynchronisated != false {
-		t.Errorf("GetHeader failed: expected flag %v; got %v", false, header.Unsynchronisated)
+	if header.Flags.Unsynchronisated != false {
+		t.Errorf("GetHeader failed: expected flag %v; got %v", false, header.Flags.Unsynchronisated)
 	}
 
 	if header.Size != 1138 {