DEV-793 Fix midday/midnight-split regression from the raw byte-advance

0d65311 (adversarial-review finding 3) switched the sensor-data byte walk
to the raw data-block size so the midday/midnight split recompute could not
corrupt the variable-length LSM6DSV FIFO walk. But a split block appears in
listOfDataBlocksInOrder as TWO entries whose recomputed sizes sum to the
on-disk size - advancing by the raw size for each part counts the block
twice, misaligning every subsequent block and eventually overrunning the
payload buffer (ArrayIndexOutOfBoundsException in parseDataBlockData).
Caught by ASM_PC_00005 Test_022, the only midday/midnight-straddling
dataset in the suite; it was not part of the 0d65311 re-run set.

The walk now advances split parts by their own recomputed share and unsplit
blocks by the raw size (identical for unsplit fixed-packet blocks; raw
remains the only valid measure for the unsplit LSM6DSV tagged FIFO). A
split LSM6DSV block now fails loudly instead of silently misparsing -
sample-count arithmetic cannot locate the split point in a tagged FIFO,
and no such recording exists yet.

Verified: Test_022 back to green against unchanged references.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: marknolan

ShimmerDriver/src/main/java/com/shimmerresearch/verisense/payloaddesign/PayloadContentsDetailsV8orAbove.java

@@ -410,8 +410,25 @@ public void parsePayloadSensorData() {
 				if(dataBlockDetails.listOfSensorClassKeys.contains(sensorClassKey)) {
 					verisenseDevice.parseDataBlockData(dataBlockDetails, byteBuffer, currentByteIndex, COMMUNICATION_TYPE.SD);
 				}
-				// RAW size: immune to midday/midnight split recomputation (see above)
-				currentByteIndex += dataBlockDetails.getQtySensorDataBytesInDatablockRaw();
+				// Advance by the on-disk bytes THIS list entry occupies. A midday/midnight-split
+				// block appears as two consecutive entries whose recomputed sizes
+				// (dataPacketSize*sampleCount) sum to the on-disk block size, so each part must
+				// advance by its own share - advancing by the raw size for each part would count
+				// the block twice and misalign every block after it. Unsplit blocks advance by
+				// the raw size, which for the variable-length LSM6DSV tagged FIFO is the only
+				// valid measure (its raw length includes tag/mag/timestamp entries that a
+				// dataPacketSize*sampleCount recomputation cannot reproduce).
+				if(dataBlockDetails.isFirstPartOfSplitDataBlock() || dataBlockDetails.isSecondPartOfSplitDataBlock()) {
+					if(dataBlockDetails.datablockSensorId==DATABLOCK_SENSOR_ID.LSM6DSV) {
+						// A split FIFO block cannot be byte-walked from sample counts; supporting
+						// it needs a FIFO-entry-aware split. Fail loudly rather than misparse
+						// every subsequent block (no such recording exists yet - see DEV-793).
+						throw new IllegalStateException("Midday/midnight-split LSM6DSV FIFO data blocks are not supported by the byte-offset walk");
+					}
+					currentByteIndex += dataBlockDetails.qtySensorDataBytesInDatablock;
+				} else {
+					currentByteIndex += dataBlockDetails.getQtySensorDataBytesInDatablockRaw();
+				}
 
 				dataBlockIndex++;