add test case to check error scenario

.github/workflows/test_decoders.yaml

@@ -0,0 +1,48 @@
+name: "Test Decoders"
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+    paths:
+      - 'internal/decoders/**'
+  push:
+    branches:
+      - 'main'
+    paths:
+      - 'internal/decoders/**'
+
+jobs:
+  test_decoders:
+    name: "test decoders"
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: ^1.23
+
+      - name: Test
+        run: go test -cover -coverprofile=decoders_coverage.txt ./internal/decoders/...
+
+      - name: Archive code coverage results
+        uses: actions/upload-artifact@v4
+        with:
+          name: decoders-code-coverage
+          path: decoders_coverage.txt # Make sure to use the same file name you chose for the "-coverprofile" in the "Test" step
+
+  code_coverage:
+    name: "Code coverage report"
+    if: github.event_name == 'pull_request' # Do not run when workflow is triggered by push to main branch
+    runs-on: ubuntu-latest
+    needs: test_decoders
+    permissions:
+      contents:      read
+      actions:       read
+      pull-requests: write
+    steps:
+      - uses: fgrosse/go-coverage-report@v1.1.1 # Consider using a Git revision for maximum security
+        with:
+          coverage-artifact-name: "decoders-code-coverage" # can be omitted if you used this default value
+          coverage-file-name: "decoders_coverage.txt" # can be omitted if you used this default value

constants.go

@@ -1,5 +1,7 @@
 package psn
 
-var PACKET_HEADER_SIZE = 16
+const (
-var MAX_UDP_PACKET_SIZE = 1500
+	PACKET_HEADER_SIZE  = 16
-var CHUNK_HEADER_SIZE = 4
+	MAX_UDP_PACKET_SIZE = 1500
+	CHUNK_HEADER_SIZE   = 4
+)

decoder.go

@@ -1,6 +1,8 @@
 package psn
 
-import "github.com/jwetzell/psn-go/internal/decoders"
+import (
+	"github.com/jwetzell/psn-go/internal/decoders"
+)
 
 type Decoder struct {
 	lastInfoPacketHeader *decoders.PacketHeaderChunk
@@ -48,11 +50,18 @@ func (d *Decoder) updateData(framePackets []decoders.DataPacketChunk) {
 	}
 }
 
-func (d *Decoder) Decode(bytes []byte) {
+func (d *Decoder) Decode(bytes []byte) error {
-	chunk := decoders.DecodeChunk(bytes)
+	chunk, err := decoders.DecodeChunk(bytes)
+
+	if err != nil {
+		return err
+	}
 
 	if chunk.Header.Id == 0x6756 {
-		infoPacket := decoders.DecodeInfoPacketChunk(bytes)
+		infoPacket, err := decoders.DecodeInfoPacketChunk(bytes)
+		if err != nil {
+			return err
+		}
 		currentInfoPacketHeader := infoPacket.Data.PacketHeader
 
 		_, ok := d.infoPacketFrames[currentInfoPacketHeader.Data.FrameId]
@@ -67,7 +76,10 @@ func (d *Decoder) Decode(bytes []byte) {
 			delete(d.infoPacketFrames, currentInfoPacketHeader.Data.FrameId)
 		}
 	} else if chunk.Header.Id == 0x6755 {
-		dataPacket := decoders.DecodeDataPacketChunk(bytes)
+		dataPacket, err := decoders.DecodeDataPacketChunk(bytes)
+		if err != nil {
+			return err
+		}
 		currentInfoPacketHeader := dataPacket.Data.PacketHeader
 
 		_, ok := d.dataPacketFrames[currentInfoPacketHeader.Data.FrameId]
@@ -82,4 +94,5 @@ func (d *Decoder) Decode(bytes []byte) {
 			delete(d.dataPacketFrames, currentInfoPacketHeader.Data.FrameId)
 		}
 	}
+	return nil
 }

encoder.go

@@ -59,7 +59,6 @@ func (e *Encoder) GetInfoPackets(timestamp uint64, trackers []Tracker) [][]byte
 }
 
 func (e *Encoder) GetDataPackets(timestamp uint64, trackers []Tracker) [][]byte {
-
 	trackerChunks := [][]byte{}
 
 	for _, tracker := range trackers {

examples/benchmark/main.go

@@ -25,7 +25,6 @@ func getNTrackers(n int) []psn.Tracker {
 }
 
 func main() {
-
 	testSizes := []int{1, 10, 100, 1000}
 	encoder := psn.Encoder{
 		SystemName:  "test encoder",
@@ -39,7 +38,6 @@ func main() {
 			benchmark(trackerCount, iterations, encoder, *decoder)
 		}
 	}
-
 }
 
 type BenchmarkResults struct {

examples/decode/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/json"
 	"fmt"
+	"log/slog"
 
 	"github.com/jwetzell/psn-go"
 )
@@ -10,18 +11,28 @@ import (
 func main() {
 	decoder := psn.NewDecoder()
 
-	infoPacketBytes := []byte{0x56, 0x67, 0x34, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+	infoPacketBytes := []byte{
+		0x56, 0x67, 0x34, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
 		0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
-		0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31}
+		0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
+	}
 
-	dataPacketBytes := []byte{0x55, 0x67, 0x28, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+	dataPacketBytes := []byte{
+		0x55, 0x67, 0x28, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
 		0x01, 0x01, 0x00, 0x14, 0x80, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x80, 0x3f, 0x00, 0x00,
-		0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f}
+		0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f,
+	}
 
-	decoder.Decode(infoPacketBytes)
+	err := decoder.Decode(infoPacketBytes)
-	decoder.Decode(dataPacketBytes)
+	if err != nil {
+		slog.Error("error decoding", "err", err)
+	}
+	err = decoder.Decode(dataPacketBytes)
+	if err != nil {
+		slog.Error("error decoding", "err", err)
+	}
 
-	fmt.Printf("decoded: %+v\n", decoder.SystemName)
+	fmt.Printf("decoded system name: %s\n", decoder.SystemName)
 
 	trackers, err := json.MarshalIndent(decoder.Trackers, "", "  ")
 	if err != nil {
@@ -29,5 +40,5 @@ func main() {
 		return
 	}
 
-	fmt.Println(string(trackers))
+	fmt.Printf("decoded trackers: \n%s\n", string(trackers))
 }

examples/encode/main.go

@@ -7,7 +7,6 @@ import (
 )
 
 func main() {
-
 	encoder := psn.Encoder{
 		SystemName:  "Server Name",
 		VersionHigh: 2,
@@ -41,5 +40,4 @@ func main() {
 		fmt.Printf("%v\n", infoPacket)
 
 	}
-
 }

examples/psn_client/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"log/slog"
 	"net"
 	"time"
 
@@ -11,14 +12,13 @@ import (
 func main() {
 	addr, err := net.ResolveUDPAddr("udp", "236.10.10.10:56565")
 	if err != nil {
-		fmt.Printf("Error %v\n", err)
+		slog.Error("error making UDP address", "err", err)
 		return
 	}
 
 	client, err := net.ListenMulticastUDP("udp", nil, addr)
-
 	if err != nil {
-		fmt.Printf("Error %v\n", err)
+		slog.Error("error listening to UDP", "err", err)
 		return
 	}
 	defer client.Close()
@@ -31,13 +31,15 @@ func main() {
 		buffer := make([]byte, 2048)
 
 		length, _, err := client.ReadFromUDP(buffer)
-
 		if err != nil {
-			fmt.Printf("Error %v", err)
+			slog.Error("error reading from UDP", "err", err)
 		}
 
 		if length > 0 {
-			decoder.Decode(buffer)
+			err := decoder.Decode(buffer)
+			if err != nil {
+				slog.Error("error decoding", "err", err)
+			}
 		}
 
 		if time.Now().UnixMilli()-lastPrintMillis > 1000 {

examples/psn_server/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"log/slog"
 	"math"
 	"net"
 	"time"
@@ -11,7 +12,6 @@ import (
 
 func main() {
 	client, err := net.Dial("udp", "236.10.10.10:56565")
-
 	if err != nil {
 		fmt.Printf("Error %v\n", err)
 		return
@@ -46,7 +46,7 @@ func main() {
 
 	for {
 		if (time.Now().UnixMilli() - lastInfoMillis) > 500 {
-			fmt.Println("Sending Info Packets")
+			slog.Info("Sending Info Packets")
 			infoPackets := encoder.GetInfoPackets(uint64(timestamp), trackers)
 			for _, infoPacket := range infoPackets {
 				client.Write(infoPacket)
@@ -71,7 +71,7 @@ func main() {
 				trackers[index].SetTimestamp(uint64(timestamp))
 			}
 
-			fmt.Println("Sending Data Packets")
+			slog.Info("Sending Data Packets")
 			dataPackets := encoder.GetDataPackets(uint64(timestamp), trackers)
 			for _, DataPacket := range dataPackets {
 				client.Write(DataPacket)
@@ -81,5 +81,4 @@ func main() {
 		}
 
 	}
-
 }

internal/decoders/chunk.go

@@ -2,6 +2,7 @@ package decoders
 
 import (
 	"encoding/binary"
+	"errors"
 )
 
 type ChunkHeader struct {
@@ -11,11 +12,16 @@ type ChunkHeader struct {
 }
 
 type Chunk struct {
-	Header    ChunkHeader
 	ChunkData []byte
+	Header    ChunkHeader
+}
+
+func DecodeChunk(bytes []byte) (Chunk, error) {
+
+	if len(bytes) < 4 {
+		return Chunk{}, errors.New("chunk must be at least 4 bytes")
 	}
 
-func DecodeChunk(bytes []byte) Chunk {
 	id := binary.LittleEndian.Uint16(bytes[0:2])
 	lengthAndFlag := binary.LittleEndian.Uint16(bytes[2:4])
 
@@ -38,6 +44,5 @@ func DecodeChunk(bytes []byte) Chunk {
 	return Chunk{
 		Header:    header,
 		ChunkData: chunk_data,
-	}
+	}, nil
-
 }

internal/decoders/chunk_test.go

@@ -3,11 +3,11 @@ package decoders
 import (
 	"fmt"
 	"reflect"
+	"strings"
 	"testing"
 )
 
-func TestChunkDecoding(t *testing.T) {
+func TestGoodChunkDecoding(t *testing.T) {
-
 	testCases := []struct {
 		description string
 		bytes       []byte
@@ -15,41 +15,54 @@ func TestChunkDecoding(t *testing.T) {
 	}{
 		{
 			description: "info packet",
-			bytes: []byte{0x56, 0x67, 0x34, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+			bytes: []byte{
+				0x56, 0x67, 0x34, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
 				0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
-				0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31},
+				0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
+			},
 			expected: Chunk{
 				Header: ChunkHeader{
 					Id:           uint16(26454),
 					DataLen:      uint16(52),
 					HasSubchunks: true,
 				},
-				ChunkData: []byte{0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+				ChunkData: []byte{
+					0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
 					0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
-					0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31},
+					0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
+				},
 			},
 		},
 		{
 			description: "data packet",
-			bytes: []byte{0x55, 0x67, 0x28, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+			bytes: []byte{
+				0x55, 0x67, 0x28, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
 				0x01, 0x01, 0x00, 0x14, 0x80, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x80, 0x3f, 0x00, 0x00,
-				0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f},
+				0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f,
+			},
 			expected: Chunk{
 				Header: ChunkHeader{
 					Id:           uint16(26453),
 					DataLen:      uint16(40),
 					HasSubchunks: true,
 				},
-				ChunkData: []byte{0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+				ChunkData: []byte{
+					0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
 					0x01, 0x01, 0x00, 0x14, 0x80, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x80, 0x3f, 0x00, 0x00,
-					0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f},
+					0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f,
+				},
 			},
 		},
 	}
 
 	for _, testCase := range testCases {
 
-		actual := DecodeChunk(testCase.bytes)
+		actual, err := DecodeChunk(testCase.bytes)
+
+		if err != nil {
+			t.Errorf("Test '%s' failed to decode chunk properly", testCase.description)
+			fmt.Println(err)
+		}
 
 		if !reflect.DeepEqual(actual, testCase.expected) {
 			t.Errorf("Test '%s' failed to decode chunk properly", testCase.description)
@@ -58,3 +71,33 @@ func TestChunkDecoding(t *testing.T) {
 		}
 	}
 }
+
+func TestBadChunkDecoding(t *testing.T) {
+	testCases := []struct {
+		description        string
+		bytes              []byte
+		errorShouldContain string
+	}{
+		{
+			description:        "empty packet",
+			bytes:              []byte{},
+			errorShouldContain: "must be at least 4 bytes",
+		},
+	}
+
+	for _, testCase := range testCases {
+
+		_, err := DecodeChunk(testCase.bytes)
+
+		if err == nil {
+			t.Errorf("Test '%s' should have failed fail to decode chunk properly", testCase.description)
+		}
+
+		if !strings.Contains(err.Error(), testCase.errorShouldContain) {
+			t.Errorf("Test '%s' did not return the correct error", testCase.description)
+			fmt.Printf("expected: %v\n", testCase.errorShouldContain)
+			fmt.Printf("actual: %v\n", err.Error())
+		}
+
+	}
+}

internal/decoders/data_packet_chunk.go

@@ -11,29 +11,39 @@ type DataPacketChunkData struct {
 }
 
 type DataPacketChunk struct {
-	Chunk Chunk
 	Data  DataPacketChunkData
+	Chunk Chunk
+}
+
+func DecodeDataPacketChunk(bytes []byte) (DataPacketChunk, error) {
+	chunk, err := DecodeChunk(bytes)
+
+	if err != nil {
+		return DataPacketChunk{}, err
 	}
 
-func DecodeDataPacketChunk(bytes []byte) DataPacketChunk {
-	chunk := DecodeChunk(bytes)
 	data := DataPacketChunkData{}
 
 	if chunk.Header.HasSubchunks && chunk.ChunkData != nil && chunk.Header.DataLen > 0 {
 		offset := 0
 
 		for offset < int(chunk.Header.DataLen) {
-
 			switch id := binary.LittleEndian.Uint16(chunk.ChunkData[offset : offset+2]); id {
-			case 0:
+			case 0x0000:
-				packet_header := DecodePacketHeaderChunk(chunk.ChunkData[offset:])
+				packet_header, err := DecodePacketHeaderChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataPacketChunk{}, err
+				}
 				data.PacketHeader = &packet_header
 				offset += 4
 				if packet_header.Chunk.Header.DataLen > 0 {
 					offset = offset + int(packet_header.Chunk.Header.DataLen)
 				}
-			case 1:
+			case 0x0001:
-				tracker_list := DecodeDataTrackerListChunk(chunk.ChunkData[offset:])
+				tracker_list, err := DecodeDataTrackerListChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataPacketChunk{}, err
+				}
 				data.TrackerList = &tracker_list
 				offset += 4
 				if tracker_list.Chunk.Header.DataLen > 0 {
@@ -49,5 +59,6 @@ func DecodeDataPacketChunk(bytes []byte) DataPacketChunk {
 	return DataPacketChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
+		nil
 }

internal/decoders/data_tracker_chunk.go

@@ -16,64 +16,89 @@ type DataTrackerChunkData struct {
 }
 
 type DataTrackerChunk struct {
-	Chunk Chunk
 	Data  DataTrackerChunkData
+	Chunk Chunk
+}
+
+func DecodeDataTrackerChunk(bytes []byte) (DataTrackerChunk, error) {
+	chunk, err := DecodeChunk(bytes)
+
+	if err != nil {
+		return DataTrackerChunk{}, err
 	}
 
-func DecodeDataTrackerChunk(bytes []byte) DataTrackerChunk {
-	chunk := DecodeChunk(bytes)
 	data := DataTrackerChunkData{}
 
 	if chunk.Header.HasSubchunks && chunk.ChunkData != nil && chunk.Header.DataLen > 0 {
 		offset := 0
 
 		for offset < int(chunk.Header.DataLen) {
-
 			switch id := binary.LittleEndian.Uint16(chunk.ChunkData[offset : offset+2]); id {
-			case 0:
+			case 0x0000:
-				pos := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				pos, err := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataTrackerChunk{}, err
+				}
 				data.Pos = &pos
 				offset += 4
 				if data.Pos.Chunk.Header.DataLen > 0 {
 					offset = offset + int(data.Pos.Chunk.Header.DataLen)
 				}
-			case 1:
+			case 0x0001:
-				speed := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				speed, err := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataTrackerChunk{}, err
+				}
 				data.Speed = &speed
 				offset += 4
 				if data.Speed.Chunk.Header.DataLen > 0 {
 					offset = offset + int(data.Speed.Chunk.Header.DataLen)
 				}
-			case 2:
+			case 0x0002:
-				ori := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				ori, err := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataTrackerChunk{}, err
+				}
 				data.Ori = &ori
 				offset += 4
 				if data.Ori.Chunk.Header.DataLen > 0 {
 					offset = offset + int(data.Ori.Chunk.Header.DataLen)
 				}
-			case 3:
+			case 0x0003:
-				status := DecodeDataTrackerStatusChunk(chunk.ChunkData[offset:])
+				status, err := DecodeDataTrackerStatusChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataTrackerChunk{}, err
+				}
 				data.Status = &status
 				offset += 4
 				if data.Status.Chunk.Header.DataLen > 0 {
 					offset = offset + int(data.Status.Chunk.Header.DataLen)
 				}
-			case 4:
+			case 0x0004:
-				accel := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				accel, err := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataTrackerChunk{}, err
+				}
 				data.Accel = &accel
 				offset += 4
 				if data.Accel.Chunk.Header.DataLen > 0 {
 					offset = offset + int(data.Accel.Chunk.Header.DataLen)
 				}
-			case 5:
+			case 0x0005:
-				trgtpos := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				trgtpos, err := DecodeDataTrackerXYZChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataTrackerChunk{}, err
+				}
 				data.TrgtPos = &trgtpos
 				offset += 4
 				if data.TrgtPos.Chunk.Header.DataLen > 0 {
 					offset = offset + int(data.TrgtPos.Chunk.Header.DataLen)
 				}
-			case 6:
+			case 0x0006:
-				timestamp := DecodeDataTrackerTimestampChunk(chunk.ChunkData[offset:])
+				timestamp, err := DecodeDataTrackerTimestampChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return DataTrackerChunk{}, err
+				}
 				data.Timestamp = &timestamp
 				offset += 4
 				if data.Timestamp.Chunk.Header.DataLen > 0 {
@@ -89,5 +114,6 @@ func DecodeDataTrackerChunk(bytes []byte) DataTrackerChunk {
 	return DataTrackerChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
+		nil
 }

internal/decoders/data_tracker_list_chunk.go

@@ -8,14 +8,21 @@ type DataTrackerListChunk struct {
 	Data  DataTrackerListChunkData
 }
 
-func DecodeDataTrackerListChunk(bytes []byte) DataTrackerListChunk {
+func DecodeDataTrackerListChunk(bytes []byte) (DataTrackerListChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
+
+	if err != nil {
+		return DataTrackerListChunk{}, err
+	}
 
 	trackers := []DataTrackerChunk{}
 	if chunk.Header.HasSubchunks && chunk.Header.DataLen > 0 {
 		offset := 0
 		for offset < int(chunk.Header.DataLen) {
-			trackerChunk := DecodeDataTrackerChunk(chunk.ChunkData[offset:])
+			trackerChunk, err := DecodeDataTrackerChunk(chunk.ChunkData[offset:])
+			if err != nil {
+				return DataTrackerListChunk{}, err
+			}
 			offset += 4
 			if trackerChunk.Chunk.Header.DataLen > 0 {
 				offset += int(trackerChunk.Chunk.Header.DataLen)
@@ -31,6 +38,6 @@ func DecodeDataTrackerListChunk(bytes []byte) DataTrackerListChunk {
 	return DataTrackerListChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
-
+		nil
 }

internal/decoders/data_tracker_status_chunk.go

@@ -2,6 +2,7 @@ package decoders
 
 import (
 	"encoding/binary"
+	"errors"
 	"math"
 )
 
@@ -14,8 +15,16 @@ type DataTrackerStatusChunk struct {
 	Data  DataTrackerStatusChunkData
 }
 
-func DecodeDataTrackerStatusChunk(bytes []byte) DataTrackerStatusChunk {
+func DecodeDataTrackerStatusChunk(bytes []byte) (DataTrackerStatusChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
+
+	if err != nil {
+		return DataTrackerStatusChunk{}, err
+	}
+
+	if len(chunk.ChunkData) < 4 {
+		return DataTrackerStatusChunk{}, errors.New("DATA_TRACKER_STATUS chunk must be at least 4 bytes")
+	}
 
 	statusBits := binary.LittleEndian.Uint32(chunk.ChunkData[0:4])
 
@@ -26,6 +35,6 @@ func DecodeDataTrackerStatusChunk(bytes []byte) DataTrackerStatusChunk {
 	return DataTrackerStatusChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
-
+		nil
 }

internal/decoders/data_tracker_timestamp_chunk.go

@@ -2,6 +2,7 @@ package decoders
 
 import (
 	"encoding/binary"
+	"errors"
 )
 
 type DataTrackerTimestampChunkData struct {
@@ -13,8 +14,16 @@ type DataTrackerTimestampChunk struct {
 	Data  DataTrackerTimestampChunkData
 }
 
-func DecodeDataTrackerTimestampChunk(bytes []byte) DataTrackerTimestampChunk {
+func DecodeDataTrackerTimestampChunk(bytes []byte) (DataTrackerTimestampChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
+
+	if err != nil {
+		return DataTrackerTimestampChunk{}, err
+	}
+
+	if len(chunk.ChunkData) < 8 {
+		return DataTrackerTimestampChunk{}, errors.New("DATA_TRACKER_TIMESTAMP chunk must be at least 8 bytes")
+	}
 
 	timestamp := binary.LittleEndian.Uint64(chunk.ChunkData[0:8])
 
@@ -25,6 +34,6 @@ func DecodeDataTrackerTimestampChunk(bytes []byte) DataTrackerTimestampChunk {
 	return DataTrackerTimestampChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
-
+		nil
 }

internal/decoders/data_tracker_xyz_chunk.go

@@ -2,6 +2,7 @@ package decoders
 
 import (
 	"encoding/binary"
+	"errors"
 	"math"
 )
 
@@ -16,8 +17,16 @@ type DataTrackerXYZChunk struct {
 	Data  DataTrackerXYZChunkData
 }
 
-func DecodeDataTrackerXYZChunk(bytes []byte) DataTrackerXYZChunk {
+func DecodeDataTrackerXYZChunk(bytes []byte) (DataTrackerXYZChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
+
+	if err != nil {
+		return DataTrackerXYZChunk{}, err
+	}
+
+	if len(chunk.ChunkData) < 12 {
+		return DataTrackerXYZChunk{}, errors.New("DATA_TRACKER_XYZ chunk must be at least 12 bytes")
+	}
 
 	xBits := binary.LittleEndian.Uint32(chunk.ChunkData[0:4])
 	yBits := binary.LittleEndian.Uint32(chunk.ChunkData[4:8])
@@ -32,6 +41,5 @@ func DecodeDataTrackerXYZChunk(bytes []byte) DataTrackerXYZChunk {
 	return DataTrackerXYZChunk{
 		Chunk: chunk,
 		Data:  data,
-	}
+	}, nil
-
 }

internal/decoders/info_packet_chunk.go

@@ -12,36 +12,47 @@ type InfoPacketChunkData struct {
 }
 
 type InfoPacketChunk struct {
-	Chunk Chunk
 	Data  InfoPacketChunkData
+	Chunk Chunk
 }
 
-func DecodeInfoPacketChunk(bytes []byte) InfoPacketChunk {
+func DecodeInfoPacketChunk(bytes []byte) (InfoPacketChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
+	if err != nil {
+		return InfoPacketChunk{}, err
+	}
 	data := InfoPacketChunkData{}
 
 	if chunk.Header.HasSubchunks && chunk.ChunkData != nil && chunk.Header.DataLen > 0 {
 		offset := 0
 
 		for offset < int(chunk.Header.DataLen) {
-
 			switch id := binary.LittleEndian.Uint16(chunk.ChunkData[offset : offset+2]); id {
-			case 0:
+			case 0x0000:
-				packet_header := DecodePacketHeaderChunk(chunk.ChunkData[offset:])
+				packet_header, err := DecodePacketHeaderChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return InfoPacketChunk{}, err
+				}
 				data.PacketHeader = &packet_header
 				offset += 4
 				if packet_header.Chunk.Header.DataLen > 0 {
 					offset = offset + int(packet_header.Chunk.Header.DataLen)
 				}
-			case 1:
+			case 0x0001:
-				system_name := DecodeInfoSystemNameChunk(chunk.ChunkData[offset:])
+				system_name, err := DecodeInfoSystemNameChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return InfoPacketChunk{}, err
+				}
 				data.SystemName = &system_name
 				offset += 4
 				if system_name.Chunk.Header.DataLen > 0 {
 					offset = offset + int(system_name.Chunk.Header.DataLen)
 				}
-			case 2:
+			case 0x0002:
-				tracker_list := DecodeInfoTrackerListChunk(chunk.ChunkData[offset:])
+				tracker_list, err := DecodeInfoTrackerListChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return InfoPacketChunk{}, err
+				}
 				data.TrackerList = &tracker_list
 				offset += 4
 				if tracker_list.Chunk.Header.DataLen > 0 {
@@ -57,5 +68,6 @@ func DecodeInfoPacketChunk(bytes []byte) InfoPacketChunk {
 	return InfoPacketChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
+		nil
 }

internal/decoders/info_system_name_chunk.go

@@ -5,21 +5,23 @@ type InfoSystemNameChunkData struct {
 }
 
 type InfoSystemNameChunk struct {
-	Chunk Chunk
 	Data  InfoSystemNameChunkData
+	Chunk Chunk
 }
 
-func DecodeInfoSystemNameChunk(bytes []byte) InfoSystemNameChunk {
+func DecodeInfoSystemNameChunk(bytes []byte) (InfoSystemNameChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
-	system_name := string(chunk.ChunkData[0:chunk.Header.DataLen])
+	if err != nil {
+		return InfoSystemNameChunk{}, err
+	}
+	data := InfoSystemNameChunkData{}
 
-	data := InfoSystemNameChunkData{
+	if chunk.Header.DataLen > 0 {
-		SystemName: system_name,
+		data.SystemName = string(chunk.ChunkData[0:chunk.Header.DataLen])
 	}
 
 	return InfoSystemNameChunk{
 		Chunk: chunk,
 		Data:  data,
-	}
+	}, nil
-
 }

internal/decoders/info_tracker_chunk.go

@@ -10,22 +10,27 @@ type InfoTrackerChunkData struct {
 }
 
 type InfoTrackerChunk struct {
-	Chunk Chunk
 	Data  InfoTrackerChunkData
+	Chunk Chunk
 }
 
-func DecodeInfoTrackerChunk(bytes []byte) InfoTrackerChunk {
+func DecodeInfoTrackerChunk(bytes []byte) (InfoTrackerChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
+	if err != nil {
+		return InfoTrackerChunk{}, err
+	}
 	data := InfoTrackerChunkData{}
 
 	if chunk.Header.HasSubchunks && chunk.ChunkData != nil && chunk.Header.DataLen > 0 {
 		offset := 0
 
 		for offset < int(chunk.Header.DataLen) {
-
 			switch id := binary.LittleEndian.Uint16(chunk.ChunkData[offset : offset+2]); id {
-			case 0:
+			case 0x0000:
-				tracker_name := DecodeInfoTrackerNameChunk(chunk.ChunkData[offset:])
+				tracker_name, err := DecodeInfoTrackerNameChunk(chunk.ChunkData[offset:])
+				if err != nil {
+					return InfoTrackerChunk{}, err
+				}
 				data.TrackerName = &tracker_name
 				offset += 4
 				if tracker_name.Chunk.Header.DataLen > 0 {
@@ -40,5 +45,6 @@ func DecodeInfoTrackerChunk(bytes []byte) InfoTrackerChunk {
 	return InfoTrackerChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
+		nil
 }

internal/decoders/info_tracker_list_chunk.go

@@ -9,14 +9,20 @@ type InfoTrackerListChunk struct {
 	Data  InfoTrackerListChunkData
 }
 
-func DecodeInfoTrackerListChunk(bytes []byte) InfoTrackerListChunk {
+func DecodeInfoTrackerListChunk(bytes []byte) (InfoTrackerListChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
+	if err != nil {
+		return InfoTrackerListChunk{}, err
+	}
 
 	trackers := []InfoTrackerChunk{}
 	if chunk.Header.HasSubchunks && chunk.Header.DataLen > 0 {
 		offset := 0
 		for offset < int(chunk.Header.DataLen) {
-			trackerChunk := DecodeInfoTrackerChunk(chunk.ChunkData[offset:])
+			trackerChunk, err := DecodeInfoTrackerChunk(chunk.ChunkData[offset:])
+			if err != nil {
+				return InfoTrackerListChunk{}, err
+			}
 			offset += 4
 			if trackerChunk.Chunk.Header.DataLen > 0 {
 				offset += int(trackerChunk.Chunk.Header.DataLen)
@@ -32,6 +38,6 @@ func DecodeInfoTrackerListChunk(bytes []byte) InfoTrackerListChunk {
 	return InfoTrackerListChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
-
+		nil
 }

internal/decoders/info_tracker_name_chunk.go

@@ -5,22 +5,26 @@ type InfoTrackerNameChunkData struct {
 }
 
 type InfoTrackerNameChunk struct {
-	Chunk Chunk
 	Data  InfoTrackerNameChunkData
+	Chunk Chunk
 }
 
-func DecodeInfoTrackerNameChunk(bytes []byte) InfoTrackerNameChunk {
+func DecodeInfoTrackerNameChunk(bytes []byte) (InfoTrackerNameChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
 
-	tracker_name := string(chunk.ChunkData[0:chunk.Header.DataLen])
+	if err != nil {
+		return InfoTrackerNameChunk{}, err
+	}
 
-	data := InfoTrackerNameChunkData{
+	data := InfoTrackerNameChunkData{}
-		TrackerName: tracker_name,
+
+	if chunk.Header.DataLen > 0 {
+		data.TrackerName = string(chunk.ChunkData[0:chunk.Header.DataLen])
 	}
 
 	return InfoTrackerNameChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
-
+		nil
 }

internal/decoders/packet_header_chunk.go

@@ -15,8 +15,11 @@ type PacketHeaderChunk struct {
 	Data  PacketHeaderChunkData
 }
 
-func DecodePacketHeaderChunk(bytes []byte) PacketHeaderChunk {
+func DecodePacketHeaderChunk(bytes []byte) (PacketHeaderChunk, error) {
-	chunk := DecodeChunk(bytes)
+	chunk, err := DecodeChunk(bytes)
+	if err != nil {
+		return PacketHeaderChunk{}, err
+	}
 
 	packet_timestamp := binary.LittleEndian.Uint64(chunk.ChunkData[0:8])
 	version_high := chunk.ChunkData[8]
@@ -35,6 +38,6 @@ func DecodePacketHeaderChunk(bytes []byte) PacketHeaderChunk {
 	return PacketHeaderChunk{
 			Chunk: chunk,
 			Data:  data,
-	}
+		},
-
+		nil
 }

internal/encoders/chunk.go

@@ -3,7 +3,6 @@ package encoders
 import "encoding/binary"
 
 func EncodeChunk(id uint16, chunkData []byte, hasSubchunks bool) []byte {
-
 	header := []byte{}
 
 	header = binary.LittleEndian.AppendUint16(header, id)

internal/encoders/chunk_test.go

@@ -0,0 +1,69 @@
+package encoders
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+
+	"github.com/jwetzell/psn-go/internal/decoders"
+)
+
+func TestChunkEncoding(t *testing.T) {
+	testCases := []struct {
+		description string
+		expected    []byte
+		chunk       decoders.Chunk
+	}{
+		{
+			description: "info packet",
+			expected: []byte{
+				0x56, 0x67, 0x34, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+				0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
+				0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
+			},
+			chunk: decoders.Chunk{
+				Header: decoders.ChunkHeader{
+					Id:           uint16(26454),
+					DataLen:      uint16(52),
+					HasSubchunks: true,
+				},
+				ChunkData: []byte{
+					0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+					0x01, 0x01, 0x00, 0x0b, 0x00, 0x53, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x4e, 0x61, 0x6d, 0x65, 0x02, 0x00, 0x11,
+					0x80, 0x01, 0x00, 0x0d, 0x80, 0x00, 0x00, 0x09, 0x00, 0x54, 0x72, 0x61, 0x63, 0x6b, 0x65, 0x72, 0x20, 0x31,
+				},
+			},
+		},
+		{
+			description: "data packet",
+			expected: []byte{
+				0x55, 0x67, 0x28, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+				0x01, 0x01, 0x00, 0x14, 0x80, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x80, 0x3f, 0x00, 0x00,
+				0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f,
+			},
+			chunk: decoders.Chunk{
+				Header: decoders.ChunkHeader{
+					Id:           uint16(26453),
+					DataLen:      uint16(40),
+					HasSubchunks: true,
+				},
+				ChunkData: []byte{
+					0x00, 0x00, 0x0c, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x03, 0x01,
+					0x01, 0x01, 0x00, 0x14, 0x80, 0x01, 0x00, 0x10, 0x80, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00, 0x80, 0x3f, 0x00, 0x00,
+					0x80, 0x3f, 0x00, 0x00, 0x80, 0x3f,
+				},
+			},
+		},
+	}
+
+	for _, testCase := range testCases {
+
+		actual := EncodeChunk(testCase.chunk.Header.Id, testCase.chunk.ChunkData, testCase.chunk.Header.HasSubchunks)
+
+		if !reflect.DeepEqual(actual, testCase.expected) {
+			t.Errorf("Test '%s' failed to encode chunk properly", testCase.description)
+			fmt.Printf("expected: %v\n", testCase.expected)
+			fmt.Printf("actual: %v\n", actual)
+		}
+	}
+}

tracker.go

@@ -12,8 +12,6 @@ type XYZData struct {
 }
 
 type Tracker struct {
-	Id        uint16
-	Name      string
 	Pos       *XYZData
 	Speed     *XYZData
 	Ori       *XYZData
@@ -21,6 +19,8 @@ type Tracker struct {
 	Accel     *XYZData
 	TrgtPos   *XYZData
 	Timestamp *uint64
+	Name      string
+	Id        uint16
 }
 
 func (t *Tracker) SetPos(x float32, y float32, z float32) {