diff options
| author | Keith Packard <keithp@keithp.com> | 2017-10-02 16:58:53 -0700 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2017-10-02 16:58:53 -0700 |
| commit | c6be13e8ef80e5afc836e04cbfe4cb17631540e4 (patch) | |
| tree | 21ac706fdadf5a248752f648cda09abe5662fdd3 /altoslib | |
| parent | 770998be2c15dd41a63520d0c8747d7cf32ec447 (diff) | |
altoslib: Allow early bail-out on bad telemetry CRC
Check the CRC status in the packet before creating a new telemetry
object.
Signed-off-by: Keith Packard <keithp@keithp.com>
Diffstat (limited to 'altoslib')
| -rw-r--r-- | altoslib/AltosTelemetry.java | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/altoslib/AltosTelemetry.java b/altoslib/AltosTelemetry.java index fe536c6a..a374519d 100644 --- a/altoslib/AltosTelemetry.java +++ b/altoslib/AltosTelemetry.java @@ -28,8 +28,11 @@ public abstract class AltosTelemetry implements AltosDataProvider { int[] bytes; /* All telemetry packets have these fields */ - public int rssi() { return AltosConvert.telem_to_rssi(AltosLib.int8(bytes, bytes.length - 3)); } - public int status() { return AltosLib.uint8(bytes, bytes.length - 2); } + static public int rssi(int[] bytes) { return AltosConvert.telem_to_rssi(AltosLib.int8(bytes, bytes.length - 3)); } + static public int status(int[] bytes) { return AltosLib.uint8(bytes, bytes.length - 2); } + + public int rssi() { return rssi(bytes); } + public int status() { return status(bytes); } /* All telemetry packets report these fields in some form */ public abstract int serial(); @@ -96,6 +99,9 @@ public abstract class AltosTelemetry implements AltosDataProvider { if (!cksum(bytes)) throw new ParseException(String.format("invalid line \"%s\"", hex), 0); + if ((status(bytes) & PKT_APPEND_STATUS_1_CRC_OK) == 0) + throw new AltosCRCException(rssi(bytes)); + /* length, data ..., rssi, status, checksum -- 4 bytes extra */ switch (bytes.length) { case AltosLib.ao_telemetry_standard_len + 4: |