feat: shorted BLE advertisements to max 31 bytes

dronetag · Sep 4, 2023 · 8da4ea2 · 8da4ea2
1 parent 2288dd1
commit 8da4ea2
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Showing 2 changed files with 8 additions and 2 deletions.
diff --git a/android/src/main/kotlin/cz/dronetag/flutter_opendroneid/scanner/BluetoothScanner.kt b/android/src/main/kotlin/cz/dronetag/flutter_opendroneid/scanner/BluetoothScanner.kt
@@ -46,9 +46,11 @@ class BluetoothScanner(
                 if (result.getPrimaryPhy() == BluetoothDevice.PHY_LE_CODED)
                     source = Pigeon.MessageSource.BLUETOOTH_LONG_RANGE;
             }
-
+            // if using BLE, max size of data is MAX_BLE_ADV_SIZE
+            // if using BT5, data can be longer up to 256 bytes
+            val isBLE = maxAdvDataLen() <= MAX_BLE_ADV_SIZE
             receiveData(
-                offsetData(bytes, BT_OFFSET),
+                if(isBLE) getDataFromIndex(bytes, BT_OFFSET, MAX_BLE_ADV_SIZE) else offsetData(bytes, BT_OFFSET),
                 result.device.address,
                 source,
                 result.rssi.toLong(),

diff --git a/android/src/main/kotlin/cz/dronetag/flutter_opendroneid/scanner/ODIDScanner.kt b/android/src/main/kotlin/cz/dronetag/flutter_opendroneid/scanner/ODIDScanner.kt
@@ -15,6 +15,7 @@ abstract class ODIDScanner(
     companion object {
         const val MAX_MESSAGE_SIZE = 25
         const val BT_OFFSET = 6
+        const val MAX_BLE_ADV_SIZE = 31
         const val WIFI_BEACON_OFFSET = 5
         const val WIFI_NAN_OFFSET = 1
     }
@@ -62,4 +63,7 @@ abstract class ODIDScanner(
 
     /// returns ByteArray without first offset elements
     inline fun offsetData(data: ByteArray, offset: Int) : ByteArray = data.copyOfRange(offset, data.size)
+
+    /// returns ByteArray with bytes from start to end
+    inline fun getDataFromIndex(data: ByteArray, start: Int, end: Int) : ByteArray = data.copyOfRange(start, end)
 }