Support canfd (#1)

* Updated Message.Length to uint16 to support message lengths up to 65,535 bytes

* Updated Signal.Lenght and Signal.Size to uint16 for payloads larger than 8 bytes

* Added payload.go and payload_tests.go

* Updated Big and Little Endian encoding methods

* Added benchmarks

* Added methods and tests to decode signed/unsigned signals in big/little endian

* Added benchmarks for UnsignedBitsLittleEndian

* Added hex string methods for Payload

* Added UnmarshalPhysicalPayload and updated bit-level methods for Payload struct

* Added UnmarshalValueDescriptionPayload and associated methods for Payload data struct

* Added decode_tests.go

* Updated decode test

* Added asserts to decode_test.go

* Added comparitive unit tests for can.Data and benchmarks for decoding

* Updated PackLittleEndian and PackBigEndian to return new big.Int and reference pointer to payload in decode methods

* Fixed units in VDM_Disconnect test

Co-authored-by: Jason Shiverick <jshiverick@rivian.coml>
Co-authored-by: Naveen Venkatesan <nvenkatesan@rivian.com>
Co-authored-by: Naveen Venkatesan <naveen.venkatesan@gmail.com>

data_test.go

@@ -331,3 +331,17 @@ func BenchmarkData_PackLittleEndian(b *testing.B) {
 		_ = data.PackLittleEndian()
 	}
 }
+
+func BenchmarkData_UnsignedBitsBigEndian(b *testing.B) {
+	var data Data
+	for i := 0; i < b.N; i++ {
+		_ = data.UnsignedBitsBigEndian(0, 16)
+	}
+}
+
+func BenchmarkData_UnsignedBitsLittleEndian(b *testing.B) {
+	var data Data
+	for i := 0; i < b.N; i++ {
+		_ = data.UnsignedBitsLittleEndian(0, 16)
+	}
+}

frame.go

@@ -26,7 +26,7 @@ type Frame struct {
 	// ID is the CAN ID
 	ID uint32
 	// Length is the number of bytes of data in the frame.
-	Length uint8
+	Length uint16
 	// Data is the frame data.
 	Data Data
 	// IsRemote is true for remote frames.
@@ -114,7 +114,7 @@ func (f *Frame) UnmarshalString(s string) error {
 			if err != nil {
 				return fmt.Errorf("invalid remote length: %v: %w", s, err)
 			}
-			frame.Length = uint8(dataLength)
+			frame.Length = uint16(dataLength)
 		}
 		*f = frame
 		return nil
@@ -123,7 +123,7 @@ func (f *Frame) UnmarshalString(s string) error {
 	if len(dataPart) > 16 || len(dataPart)%2 != 0 {
 		return fmt.Errorf("invalid data length: %v", s)
 	}
-	frame.Length = uint8(len(dataPart) / 2)
+	frame.Length = uint16(len(dataPart) / 2)
 	// Parse: Data
 	decodedData, err := hex.DecodeString(dataPart)
 	if err != nil {

frame_json.go

@@ -10,7 +10,7 @@ import (
 type jsonFrame struct {
 	ID       uint32  `json:"id"`
 	Data     *string `json:"data"`
-	Length   *uint8  `json:"length"`
+	Length   *uint16 `json:"length"`
 	Extended *bool   `json:"extended"`
 	Remote   *bool   `json:"remote"`
 }
@@ -69,7 +69,7 @@ func (f *Frame) UnmarshalJSON(jsonData []byte) error {
 		}
 		f.Data = Data{}
 		copy(f.Data[:], data)
-		f.Length = uint8(len(data))
+		f.Length = uint16(len(data))
 	} else {
 		f.Data = Data{}
 		f.Length = 0

frame_json_test.go

@@ -102,7 +102,7 @@ func (Frame) Generate(rand *rand.Rand, size int) reflect.Value {
 	} else {
 		f.ID = rand.Uint32() & MaxID
 	}
-	f.Length = uint8(rand.Intn(9))
+	f.Length = uint16(rand.Intn(9))
 	if !f.IsRemote {
 		_, _ = rand.Read(f.Data[:f.Length])
 	}

internal/generate/compile.go

@@ -62,7 +62,7 @@ func (c *compiler) collectDescriptors() {
 				Name:       string(def.Name),
 				ID:         def.MessageID.ToCAN(),
 				IsExtended: def.MessageID.IsExtended(),
-				Length:     uint8(def.Size),
+				Length:     uint16(def.Size),
 				SenderNode: string(def.Transmitter),
 			}
 			for _, signalDef := range def.Signals {
@@ -73,8 +73,8 @@ func (c *compiler) collectDescriptors() {
 					IsMultiplexer:    signalDef.IsMultiplexerSwitch,
 					IsMultiplexed:    signalDef.IsMultiplexed,
 					MultiplexerValue: uint(signalDef.MultiplexerSwitch),
-					Start:            uint8(signalDef.StartBit),
-					Length:           uint8(signalDef.Size),
+					Start:            uint16(signalDef.StartBit),
+					Length:           uint16(signalDef.Size),
 					Scale:            signalDef.Factor,
 					Offset:           signalDef.Offset,
 					Min:              signalDef.Minimum,