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Merged
ericwenn merged 1 commit into from
Feb 27, 2026
Merged

feat(socketcan): export Frame for Marshal/Unmarshal #373

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36 changes: 18 additions & 18 deletions pkg/socketcan/frame.go
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Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ const (
// The interceptor is called if and only if the frame transmission/receival is a success.
type FrameInterceptor func(fr can.Frame)

// frame represents a SocketCAN frame.
// Frame represents a SocketCAN frame.
//
// The format specified in the Linux SocketCAN kernel module:
//
Expand All @@ -72,7 +72,7 @@ type FrameInterceptor func(fr can.Frame)
// __u8 __res1; /* reserved / padding */
// __u8 data[8] __attribute__((aligned(8)));
// };
type frame struct {
type Frame struct {
// idAndFlags is the combined CAN ID and flags.
idAndFlags uint32
// dataLengthCode is the frame payload length in bytes.
Expand All @@ -83,21 +83,21 @@ type frame struct {
data [8]byte
}

func (f *frame) unmarshalBinary(b []byte) {
func (f *Frame) UnmarshalBinary(b []byte) {
_ = b[lengthOfFrame-1] // bounds check
f.idAndFlags = binary.LittleEndian.Uint32(b[indexOfID : indexOfID+lengthOfID])
f.dataLengthCode = b[indexOfDataLengthCode]
copy(f.data[:], b[indexOfData:lengthOfFrame])
}

func (f *frame) marshalBinary(b []byte) {
func (f *Frame) MarshalBinary(b []byte) {
_ = b[lengthOfFrame-1] // bounds check
binary.LittleEndian.PutUint32(b[indexOfID:indexOfID+lengthOfID], f.idAndFlags)
b[indexOfDataLengthCode] = f.dataLengthCode
copy(b[indexOfData:], f.data[:])
}

func (f *frame) decodeFrame() can.Frame {
func (f *Frame) DecodeFrame() can.Frame {
return can.Frame{
ID: f.id(),
Length: f.dataLengthCode,
Expand All @@ -107,7 +107,7 @@ func (f *frame) decodeFrame() can.Frame {
}
}

func (f *frame) encodeFrame(cf can.Frame) {
func (f *Frame) EncodeFrame(cf can.Frame) {
f.idAndFlags = cf.ID
if cf.IsRemote {
f.idAndFlags |= idFlagRemote
Expand All @@ -119,26 +119,26 @@ func (f *frame) encodeFrame(cf can.Frame) {
f.data = cf.Data
}

func (f *frame) isExtended() bool {
func (f *Frame) isExtended() bool {
return f.idAndFlags&idFlagExtended > 0
}

func (f *frame) isRemote() bool {
func (f *Frame) isRemote() bool {
return f.idAndFlags&idFlagRemote > 0
}

func (f *frame) isError() bool {
func (f *Frame) IsError() bool {
return f.idAndFlags&idFlagError > 0
}

func (f *frame) id() uint32 {
func (f *Frame) id() uint32 {
if f.isExtended() {
return f.idAndFlags & idMaskExtended
}
return f.idAndFlags & idMaskStandard
}

func (f *frame) decodeErrorFrame() ErrorFrame {
func (f *Frame) DecodeErrorFrame() ErrorFrame {
return ErrorFrame{
ErrorClass: f.errorClass(),
LostArbitrationBit: f.lostArbitrationBit(),
Expand All @@ -150,31 +150,31 @@ func (f *frame) decodeErrorFrame() ErrorFrame {
}
}

func (f *frame) errorClass() ErrorClass {
func (f *Frame) errorClass() ErrorClass {
return ErrorClass(f.idAndFlags &^ idFlagError)
}

func (f *frame) lostArbitrationBit() uint8 {
func (f *Frame) lostArbitrationBit() uint8 {
return f.data[indexOfLostArbitrationBit]
}

func (f *frame) controllerError() ControllerError {
func (f *Frame) controllerError() ControllerError {
return ControllerError(f.data[indexOfControllerError])
}

func (f *frame) protocolError() ProtocolViolationError {
func (f *Frame) protocolError() ProtocolViolationError {
return ProtocolViolationError(f.data[indexOfProtocolError])
}

func (f *frame) protocolErrorLocation() ProtocolViolationErrorLocation {
func (f *Frame) protocolErrorLocation() ProtocolViolationErrorLocation {
return ProtocolViolationErrorLocation(f.data[indexOfProtocolViolationErrorLocation])
}

func (f *frame) transceiverError() TransceiverError {
func (f *Frame) transceiverError() TransceiverError {
return TransceiverError(f.data[indexOfTransceiverError])
}

func (f *frame) controllerSpecificInformation() [LengthOfControllerSpecificInformation]byte {
func (f *Frame) controllerSpecificInformation() [LengthOfControllerSpecificInformation]byte {
var ret [LengthOfControllerSpecificInformation]byte
start := indexOfControllerSpecificInformation
end := start + LengthOfControllerSpecificInformation
Expand Down
40 changes: 20 additions & 20 deletions pkg/socketcan/frame_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -14,10 +14,10 @@ func TestFrame_MarshalUnmarshalBinary_Property_Idempotent(t *testing.T) {
return data
}
g := func(data [lengthOfFrame]byte) [lengthOfFrame]byte {
var f frame
f.unmarshalBinary(data[:])
var f Frame
f.UnmarshalBinary(data[:])
var newData [lengthOfFrame]byte
f.marshalBinary(newData[:])
f.MarshalBinary(newData[:])
return newData
}
assert.NilError(t, quick.CheckEqual(f, g, nil))
Expand All @@ -27,7 +27,7 @@ func TestFrame_EncodeDecode(t *testing.T) {
for _, tt := range []struct {
msg string
frame can.Frame
socketCANFrame frame
socketCANFrame Frame
}{
{
msg: "data",
Expand All @@ -36,7 +36,7 @@ func TestFrame_EncodeDecode(t *testing.T) {
Length: 8,
Data: can.Data{1, 2, 3, 4, 5, 6, 7, 8},
},
socketCANFrame: frame{
socketCANFrame: Frame{
idAndFlags: 0x00000001,
dataLengthCode: 8,
data: [8]byte{1, 2, 3, 4, 5, 6, 7, 8},
Expand All @@ -48,7 +48,7 @@ func TestFrame_EncodeDecode(t *testing.T) {
ID: 0x00000001,
IsExtended: true,
},
socketCANFrame: frame{
socketCANFrame: Frame{
idAndFlags: 0x80000001,
},
},
Expand All @@ -58,7 +58,7 @@ func TestFrame_EncodeDecode(t *testing.T) {
ID: 0x00000001,
IsRemote: true,
},
socketCANFrame: frame{
socketCANFrame: Frame{
idAndFlags: 0x40000001,
},
},
Expand All @@ -69,38 +69,38 @@ func TestFrame_EncodeDecode(t *testing.T) {
IsExtended: true,
IsRemote: true,
},
socketCANFrame: frame{
socketCANFrame: Frame{
idAndFlags: 0xc0000001,
},
},
} {
t.Run(tt.msg, func(t *testing.T) {
t.Run("encode", func(t *testing.T) {
var actual frame
actual.encodeFrame(tt.frame)
var actual Frame
actual.EncodeFrame(tt.frame)
assert.Equal(t, tt.socketCANFrame, actual)
})
t.Run("decode", func(t *testing.T) {
assert.Equal(t, tt.frame, tt.socketCANFrame.decodeFrame())
assert.Equal(t, tt.frame, tt.socketCANFrame.DecodeFrame())
})
})
}
}

func TestFrame_IsError(t *testing.T) {
assert.Assert(t, (&frame{idAndFlags: 0x20000001}).isError())
assert.Assert(t, !(&frame{idAndFlags: 0x00000001}).isError())
assert.Assert(t, (&Frame{idAndFlags: 0x20000001}).IsError())
assert.Assert(t, !(&Frame{idAndFlags: 0x00000001}).IsError())
}

func TestFrame_DecodeErrorFrame(t *testing.T) {
for _, tt := range []struct {
msg string
f frame
f Frame
expected ErrorFrame
}{
{
msg: "lost arbitration",
f: frame{
f: Frame{
idAndFlags: 0x20000002,
dataLengthCode: 8,
data: [8]byte{
Expand All @@ -114,7 +114,7 @@ func TestFrame_DecodeErrorFrame(t *testing.T) {
},
{
msg: "controller",
f: frame{
f: Frame{
idAndFlags: 0x20000004,
dataLengthCode: 8,
data: [8]byte{
Expand All @@ -129,7 +129,7 @@ func TestFrame_DecodeErrorFrame(t *testing.T) {
},
{
msg: "protocol violation",
f: frame{
f: Frame{
idAndFlags: 0x20000008,
dataLengthCode: 8,
data: [8]byte{
Expand All @@ -147,7 +147,7 @@ func TestFrame_DecodeErrorFrame(t *testing.T) {
},
{
msg: "transceiver",
f: frame{
f: Frame{
idAndFlags: 0x20000010,
dataLengthCode: 8,
data: [8]byte{
Expand All @@ -165,7 +165,7 @@ func TestFrame_DecodeErrorFrame(t *testing.T) {
},
{
msg: "controller-specific information",
f: frame{
f: Frame{
idAndFlags: 0x20000001,
dataLengthCode: 8,
data: [8]byte{
Expand All @@ -186,7 +186,7 @@ func TestFrame_DecodeErrorFrame(t *testing.T) {
},
} {
t.Run(tt.msg, func(t *testing.T) {
assert.Equal(t, tt.expected, tt.f.decodeErrorFrame())
assert.Equal(t, tt.expected, tt.f.DecodeErrorFrame())
})
}
}
14 changes: 7 additions & 7 deletions pkg/socketcan/receiver.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ type Receiver struct {
opts receiverOpts
rc io.ReadCloser
sc *bufio.Scanner
frame frame
frame Frame
}

func NewReceiver(rc io.ReadCloser, opt ...ReceiverOption) *Receiver {
Expand All @@ -44,26 +44,26 @@ func scanFrames(data []byte, _ bool) (int, []byte, error) {

func (r *Receiver) Receive() bool {
ok := r.sc.Scan()
r.frame = frame{}
r.frame = Frame{}
if ok {
r.frame.unmarshalBinary(r.sc.Bytes())
r.frame.UnmarshalBinary(r.sc.Bytes())
if r.opts.frameInterceptor != nil {
r.opts.frameInterceptor(r.frame.decodeFrame())
r.opts.frameInterceptor(r.frame.DecodeFrame())
}
}
return ok
}

func (r *Receiver) HasErrorFrame() bool {
return r.frame.isError()
return r.frame.IsError()
}

func (r *Receiver) Frame() can.Frame {
return r.frame.decodeFrame()
return r.frame.DecodeFrame()
}

func (r *Receiver) ErrorFrame() ErrorFrame {
return r.frame.decodeErrorFrame()
return r.frame.DecodeErrorFrame()
}

func (r *Receiver) Err() error {
Expand Down
6 changes: 3 additions & 3 deletions pkg/socketcan/transmitter.go
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Original file line number Diff line number Diff line change
Expand Up @@ -43,10 +43,10 @@ func (t *Transmitter) TransmitMessage(ctx context.Context, m can.Message) error

// TransmitFrame transmits a CAN frame.
func (t *Transmitter) TransmitFrame(ctx context.Context, f can.Frame) error {
var scf frame
scf.encodeFrame(f)
var scf Frame
scf.EncodeFrame(f)
data := make([]byte, lengthOfFrame)
scf.marshalBinary(data)
scf.MarshalBinary(data)
if deadline, ok := ctx.Deadline(); ok {
if err := t.conn.SetWriteDeadline(deadline); err != nil {
return fmt.Errorf("transmit frame: %w", err)
Expand Down