Define and detect different packet types (2,2e,2+,2.2)

app/Classes/FTN.php

@@ -59,12 +59,22 @@ abstract class FTN
 	 */
 	protected static function unpackheader(array $pack): string
 	{
-		return join('/',
-			collect($pack)
-				->sortBy(function($k,$v) {return $k[0];})
-				->transform(function($k,$v) {return $k[1].$v;})
-				->values()
-				->toArray()
-		);
+		// Check that our header is correct
+		if (app()->environment('local')) {
+			$c = 0;
+			foreach (collect($pack) as $item) {
+				if ($c !== $item[0])
+					throw new \Exception('Invalid header');
+
+				$c += $item[2];
+			}
+		}
+
+		return collect($pack)
+			->sortBy(function($k,$v) {return $k[0];})
+			->transform(function($k,$v) {return $k[1].$v;})
+			->values()
+			->join('/');
+		;
 	}
 }