add decode functions for info and data packets

internal/decoders/info_packet_chunk.go

@@ -0,0 +1,68 @@
+package decoders
+
+import (
+	"encoding/binary"
+	"log/slog"
+)
+
+type InfoPacketChunkData struct {
+	PacketHeader *PacketHeaderChunk
+	SystemName   *InfoSystemNameChunk
+	TrackerList  *InfoTrackerListChunk
+}
+
+type EmptyData struct{}
+
+func decodeInfoPacketChunkData(infoPacketChunk Chunk) InfoPacketChunkData {
+	data := InfoPacketChunkData{}
+
+	if infoPacketChunk.Header.HasSubchunks && infoPacketChunk.ChunkData != nil && infoPacketChunk.Header.DataLen > 0 {
+		offset := 0
+
+		for offset < int(infoPacketChunk.Header.DataLen) {
+
+			switch id := binary.LittleEndian.Uint16(infoPacketChunk.ChunkData[offset : offset+2]); id {
+			case 0:
+				packet_header := DecodePacketHeaderChunk(infoPacketChunk.ChunkData[offset:])
+				data.PacketHeader = &packet_header
+				offset = offset + CHUNK_HEADER_SIZE
+				if packet_header.Chunk.Header.DataLen > 0 {
+					offset = offset + int(packet_header.Chunk.Header.DataLen)
+				}
+			case 1:
+				system_name := DecodeInfoSystemNameChunk(infoPacketChunk.ChunkData[offset:])
+				data.SystemName = &system_name
+				offset = offset + CHUNK_HEADER_SIZE
+				if system_name.Chunk.Header.DataLen > 0 {
+					offset = offset + int(system_name.Chunk.Header.DataLen)
+				}
+			case 2:
+				tracker_list := DecodeInfoTrackerListChunk(infoPacketChunk.ChunkData[offset:])
+				data.TrackerList = &tracker_list
+				offset = offset + CHUNK_HEADER_SIZE
+				if tracker_list.Chunk.Header.DataLen > 0 {
+					offset = offset + int(tracker_list.Chunk.Header.DataLen)
+				}
+
+			default:
+				slog.Error("unhandled info packet id", "id", id)
+			}
+		}
+	}
+	return data
+}
+
+type InfoPacketChunk struct {
+	Chunk Chunk
+	Data  InfoPacketChunkData
+}
+
+func DecodeInfoPacketChunk(bytes []byte) InfoPacketChunk {
+	chunk := DecodeChunk(bytes)
+	data := decodeInfoPacketChunkData(chunk)
+
+	return InfoPacketChunk{
+		Chunk: chunk,
+		Data:  data,
+	}
+}