How can I handle raw bytes on dart? - flutter

Question

I'm totally new at app developing.
I trying to communicate with C-written end device via raw UDP packet. (such a modbus-like protocol)
And I'm suffering pain with serial/deserializing class(struct).
Here is a simple class, Packet which contain uint32, uint16, uint8.
Pack() is working, but are there any better way to achieve that?
I don't know how can I implement Unpack() method. I mean, how can I convert Uint8List to int?
import 'dart:typed_data';
void main() {
var pkt = new Packet();
pkt.TID = 0x01234567;
pkt.Src = 0x89;
pkt.Des = 0xab;
pkt.Data = 0xcdef;
var buf = pkt.Pack();
print('Packed: ${buf}');
var pkt_2 = new Packet();
if (pkt_2.Unpack(buf) != null) {
print("panic!");
return;
}
print('UnPacked: ${pkt_2.toString()}');
}
class Packet {
int TID; // uint32
int Src; // uint8
int Des; // uint8
int Data; // uint16
static const SIZE = 8;
String toString() {
return 'TID: ${TID.toRadixString(16)}, Src:${Src.toRadixString(16)}, Des:${Des.toRadixString(16)}, Data:${Data.toRadixString(16)}';
}
Uint8List Pack() {
var buf = Byteconv.itou32(TID) +
Byteconv.itou8(Src) +
Byteconv.itou8(Des) +
Byteconv.itou16(Data);
return Uint8List.fromList(buf);
}
Error Unpack(Uint8List buf) {
if (buf.length != SIZE) {
return Error();
}
// What can I do?
// TID =
// Src =
// Des =
// Data =
return null;
}
}
class Byteconv {
static Uint8List itou64(int val) {
return Uint8List(8)..buffer.asByteData().setUint64(0, val, Endian.big);
}
static Uint8List itou32(int val) {
return Uint8List(4)..buffer.asByteData().setUint32(0, val, Endian.big);
}
static Uint8List itou16(int val) {
return Uint8List(2)..buffer.asByteData().setUint16(0, val, Endian.big);
}
static Uint8List itou8(int u8) {
return Uint8List(1)..buffer.asUint8List()[0] = u8;
}
}
SOLVED
var buf_view = ByteData.sublistView(buf);
TID = buf_view.getUint32(0);
Src = buf_view.getUint8(4);
Des = buf_view.getUint8(5);
Data = buf_view.getUint16(6);