Merge pull request #51 from sparkfun/pcUpdates

Handle zero payload RTCM and UBX correctly

Author: PaulZC

library.properties

@@ -1,5 +1,5 @@
 name=SparkFun Extensible Message Parser
-version=1.0.4
+version=1.0.5
 author=SparkFun Electronics
 maintainer=SparkFun Electronics <sparkfun.com>
 sentence=Library to parse structured serial streams

src/Parse_RTCM.cpp

@@ -60,7 +60,14 @@ bool sempRtcmReadCrc(SEMP_PARSE_STATE *parse, uint8_t data)
 
     // Process the message if CRC is valid
     if ((parse->crc == 0) || (parse->badCrc && (!parse->badCrc(parse))))
+    {
+        if (parse->length == 6)
+            sempPrintf(parse->printDebug,
+                    "SEMP: %s RTCM 0x%04x (%d) bytes, \"filler\" message",
+                    parse->parserName,
+                    parse->length, parse->length);
         parse->eomCallback(parse, parse->type); // Pass parser array index
+    }
 
     // Display the RTCM messages with bad CRC
     else
@@ -128,7 +135,15 @@ bool sempRtcmReadLength2(SEMP_PARSE_STATE *parse, uint8_t data)
     SEMP_SCRATCH_PAD *scratchPad = (SEMP_SCRATCH_PAD *)parse->scratchPad;
 
     scratchPad->rtcm.bytesRemaining |= data;
-    parse->state = sempRtcmReadMessage1;
+    if (scratchPad->rtcm.bytesRemaining == 0) // Handle zero length messages - 10403 "filler" messages
+    {
+        scratchPad->rtcm.message = 0; // Clear the previous message number
+        scratchPad->rtcm.crc = parse->crc;
+        scratchPad->rtcm.bytesRemaining = 3;
+        parse->state = sempRtcmReadCrc; // Jump to the CRC
+    }
+    else
+        parse->state = sempRtcmReadMessage1;
     return true;
 }
 

src/Parse_UBLOX.cpp

@@ -101,7 +101,10 @@ bool sempUbloxLength2(SEMP_PARSE_STATE *parse, uint8_t data)
 
     // Save the second length byte
     scratchPad->ublox.bytesRemaining |= ((uint16_t)data) << 8;
-    parse->state = sempUbloxPayload;
+    if (scratchPad->ublox.bytesRemaining == 0) // Handle zero length messages - e.g. UBX-UPD
+        parse->state = sempUbloxCkA; // Jump to CRC
+    else
+        parse->state = sempUbloxPayload;
     return true;
 }
 

src/SparkFun_Extensible_Message_Parser.cpp

@@ -22,6 +22,7 @@ License: MIT. Please see LICENSE.md for more details
 // Macros
 //----------------------------------------
 
+// Align x to multiples of 8: 0->0; 1->8; 8->8; 9->16
 #define SEMP_ALIGN(x)   ((x + SEMP_ALIGNMENT_MASK) & (~SEMP_ALIGNMENT_MASK))
 
 //----------------------------------------