From a23cdd709222dfe8e0b630decc1f92ea72881e41 Mon Sep 17 00:00:00 2001
From: Artem Titoulenko <artem.titoulenko@gmail.com>
Date: Wed, 10 Nov 2021 15:52:55 -0500
Subject: [PATCH] unpack with struct :o

---
 main.go | 21 ++++++++++++---------
 util.go |  5 +++++
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/main.go b/main.go
index 7cb566c..e1ac43c 100644
--- a/main.go
+++ b/main.go
@@ -109,14 +109,17 @@ func handleMessage(ctx context.Context, buf []byte) {
 		return
 	}
 
+	type FLAP struct {
+		Channel        uint8
+		SequenceNumber uint16
+		DataLength     uint16
+	}
+
+	flap := FLAP{}
+	panicIfError(binary.Read(messageBuf, binary.BigEndian, &flap))
+
 	// Start parsing FLAP header
-	channel := mustReadNBytes(messageBuf, 1)[0]
-	log.Println("Message for channel: ", channel)
-
-	datagramSeqNum := mustReadNBytes(messageBuf, 2)
-	log.Println("Datagram Sequence Number: ", binary.BigEndian.Uint16(datagramSeqNum))
-
-	dataLength := mustReadNBytes(messageBuf, 2)
-	log.Println("Data Length: ", binary.BigEndian.Uint16(dataLength))
-
+	log.Println("Message for channel: ", flap.Channel)
+	log.Println("Datagram Sequence Number: ", flap.SequenceNumber)
+	log.Println("Data Length: ", flap.DataLength)
 }
diff --git a/util.go b/util.go
index 6f6a0b8..2aa5091 100644
--- a/util.go
+++ b/util.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"bytes"
+	"encoding/binary"
 	"encoding/hex"
 	"fmt"
 	"io"
@@ -42,3 +43,7 @@ func mustReadNBytes(buf *bytes.Buffer, n int) []byte {
 	panicIfError(err)
 	return res
 }
+
+func mustRead(buf *bytes.Buffer, dest interface{}) {
+	panicIfError(binary.Read(buf, binary.BigEndian, dest))
+}