Fixed issue of writing 13 bytes sendSerialMessage with causes error Received message of unknown type 0x0001

[loune]

I came across an issue where the Bean with become unresponsive after writing 13 bytes. I also get the logcat message Received message of unknown type 0x0001 when that happens. Googling seems to show a similar instance of this reported, but with scratch data ( http://beantalk.punchthrough.com/t/is-bean-still-supported-by-punchthrough/4056/2 ).

This only happens with 13 bytes, 12 bytes and 14 bytes are fine, indicating that this is possibly a boundary issue. I looked through the code, and found an issue in GattSerialTransportProfile.sendMessage

bean-sdk-android/sdk/src/main/java/com/punchthrough/bean/sdk/internal/serial/GattSerialTransportProfile.java

Line 207 in dc33e8c

int packets = (int) (message.size() / PACKET_TX_MAX_PAYLOAD_LENGTH);

int packets = (int) (message.size() / PACKET_TX_MAX_PAYLOAD_LENGTH);
PACKET_TX_MAX_PAYLOAD_LENGTH is 19

• when message.size() is 18, packets is 0
• when message.size() is 19, packets is 1, when it should be 0.
• when message.size() is 20, packets is 1.

I've refactored packets to indicate the number of total packets, such that:

• when message.size() is 18, packets is 1
• when message.size() is 19, packets is 1
• when message.size() is 20, packets is 2

and changed the following new GattSerialPacket logic to use pre-decrement on packets

I've also added a test case to illustrate the issue.

[kdjani]

Nice find loune. We had have been hitting issues with sendSerial and my intuition tells me that this what we have been hitting. In general, I have found the Bean Android SDK to be buggy and lacking in so many ways.