add filter for orphans to make rdrgen happy

edosl0util/rdrgen.py

@@ -25,6 +25,47 @@ def iter_pkts(l0_files):
                 yield pkt
 
 
+def filter_group_orphans(s):
+    """
+    Filter out any packets in a group that do not fall withing the expected
+    sequence id series and expected packets per group.
+
+    This is useful for input RDR packet streams received from direct braodcast
+    that may have sub-ideal packet sequences that RDR generation does not play
+    well with.
+    """
+    seqnums = {}
+    viirs_apids = set(ViirsScienceApidInfo.apids)
+
+    for p in iter(s):
+        if p.apid in viirs_apids:
+            group_size = ViirsScienceApidInfo.get_packets_per_scan(p.apid)
+            # Not groupped
+            if group_size == 1:
+                yield p
+                continue
+            # Start of new group
+            if p.is_first():
+                seqnums[p.apid] = p.seqid
+                yield p
+                continue
+            # If not in seqnums we must not have seen a first packet for this
+            # APID so it must be hanging, drop it.
+            if p.apid not in seqnums:
+                continue
+            # Packet does not have sequence number expected to be part of this
+            # group, must be an orphan, drop it.
+            # Ok to assume VIIRS here because it's the only one using groups.
+            if not ViirsGroupedPacketTimeTracker.check_sequence_number(
+                p.seqid, seqnums[p.apid], group_size
+            ):
+                continue
+            yield p
+
+        else:
+            yield p
+
+
 def packets_to_rdrs(sat, l0_files, **kwargs):
     return build_rdr(sat, iter_pkts(l0_files), **kwargs)