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Fix out of order message assembly #232

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Merged
M0r13n merged 4 commits into from
Oct 11, 2026
Merged

Fix out of order message assembly #232

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b188ca6
fix: out of order message assembly
M0r13n Oct 11, 2026
96d893b
fix: out of order message assembly
M0r13n Oct 11, 2026
d3e469c
chore: changelog
M0r13n Oct 11, 2026
aed7841
chore: add a more complex reassembly test case
M0r13n Oct 11, 2026
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5 changes: 5 additions & 0 deletions CHANGELOG.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,11 @@
counts and numbers
* tag blocks with a malformed checksum (missing, repeated `*` or non-hex) are
treated as invalid
* stricter multi-fragment message assembly
* messages are only assembled from fragments received in order,
starting with fragment 1 (matches libais and gpsd behavior)
* orphaned fragments (no fragment 1 seen) and out-of-order fragments
are dropped instead of being buffered or merged
-------------------------------------------------------------------------------
Version 3.3.0 04 Oct 2026
-------------------------------------------------------------------------------
Expand Down
23 changes: 15 additions & 8 deletions pyais/stream.py
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Original file line number Diff line number Diff line change
Expand Up @@ -183,16 +183,23 @@ def _assemble_messages(self) -> Generator[NMEAMessage, None, None]:
# A unique stream is identified by the following tuple
slot = (seq_id, msg.channel, msg.talker_id, msg.type, msg.frag_cnt)

if slot not in buffer:
# Create a new array in the buffer that has enough space for all fragments
buffer[slot] = [None, ] * max(msg.fragment_count, 0xff)

buffer[slot][msg.frag_num - 1] = msg
msg_parts = buffer[slot][0:msg.fragment_count]
if msg.frag_num == 1:
# start (overwrites any pending)
buffer[slot] = [msg] + [None] * (msg.frag_cnt - 1)
elif slot in buffer:
if msg.frag_num == sum(p is not None for p in buffer[slot]) + 1:
# strictly contiguous
buffer[slot][msg.frag_num - 1] = msg
else:
# drop out-of-order fragment
continue
else:
# orphan fragment (no start seen)
continue

# Check if all fragments are found
not_none_parts = [m for m in msg_parts if m is not None]
if not_none_parts and len(not_none_parts) == msg.fragment_count:
not_none_parts = [m for m in buffer[slot] if m is not None]
if len(not_none_parts) == msg.frag_cnt:
msg = NMEAMessage.assemble_from_iterable(not_none_parts)
yield self.__insert_wrapper_msg(msg)
del buffer[slot]
Expand Down
190 changes: 56 additions & 134 deletions tests/multi.txt
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Original file line number Diff line number Diff line change
@@ -1,134 +1,56 @@
#fragments = []
#seen = set()
#for sentence_type in ("VDM", "VDO"):
# for channel in ("A", "B"):
# for i in range(10):
# key = str(i) + channel + sentence_type + "X"
# mmsi = 123456789 + i * 10 + ord(channel) + ord(sentence_type[0]) + ord(sentence_type[1]) + ord(sentence_type[2])
# assert mmsi not in seen
# seen.add(mmsi)
# msg = MessageType8.create(mmsi=mmsi, data=b"".join(key.encode("ascii") for _ in range(20)))
# fragments.extend(encode_msg(msg, seq_id=i, radio_channel=channel, sentence_type=sentence_type))
#
#random.shuffle(fragments)
#print("\n".join(fragments))
!AIVDO,3,3,1,A,F351ETA?F351ETA?F351ETA?F351ETA?F351ETA?F351ETA?,0*15
!AIVDM,3,3,7,B,F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=,0*12
!AIVDM,3,3,2,B,F392ETA=F392ETA=F392ETA=F392ETA=F392ETA=F392ETA=,0*17
!AIVDO,3,3,8,B,F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?,0*1F
!AIVDO,3,3,2,B,F392ETA?F392ETA?F392ETA?F392ETA?F392ETA?F392ETA?,0*15
!AIVDM,3,3,8,B,F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=,0*1D
!AIVDM,3,2,6,A,ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=,0*1C
!AIVDM,3,2,9,A,ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=,0*0F
!AIVDO,3,2,4,B,ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?,0*14
!AIVDO,3,2,7,B,ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?,0*1B
!AIVDM,3,1,1,A,81mg>Ah00351ETA=F351ETA=F351ETA=F351ETA=F351ETA=F351ETA=F351,0*36
!AIVDM,3,2,7,B,ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=,0*19
!AIVDM,3,3,6,A,F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=,0*10
!AIVDM,3,2,3,B,ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=,0*6D
!AIVDO,3,2,2,B,ETA?F392ETA?F392ETA?F392ETA?F392ETA?F392ETA?F392ETA?F392ETA?,0*6A
!AIVDO,3,1,0,A,81mg>?h00311ETA?F311ETA?F311ETA?F311ETA?F311ETA?F311ETA?F311,0*4F
!AIVDM,3,3,6,B,F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=,0*13
!AIVDM,3,1,0,A,81mg>?@00311ETA=F311ETA=F311ETA=F311ETA=F311ETA=F311ETA=F311,0*65
!AIVDO,3,1,8,B,81mg>T0003Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2,0*14
!AIVDO,3,2,9,B,ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?,0*0D
!AIVDO,3,3,4,B,F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?,0*13
!AIVDM,3,1,2,A,81mg>D@00391ETA=F391ETA=F391ETA=F391ETA=F391ETA=F391ETA=F391,0*14
!AIVDM,3,1,6,A,81mg>N@003I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1ETA=F3I1,0*6A
!AIVDO,3,2,7,A,ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?,0*1B
!AIVDM,3,2,5,B,ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=,0*13
!AIVDO,3,1,6,A,81mg>Nh003I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1,0*40
!AIVDO,3,2,5,B,ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?,0*11
!AIVDO,3,3,0,B,F312ETA?F312ETA?F312ETA?F312ETA?F312ETA?F312ETA?,0*17
!AIVDO,3,3,7,A,F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?,0*13
!AIVDO,3,2,6,A,ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?,0*1E
!AIVDM,3,3,2,A,F391ETA=F391ETA=F391ETA=F391ETA=F391ETA=F391ETA=,0*14
!AIVDO,3,3,2,A,F391ETA?F391ETA?F391ETA?F391ETA?F391ETA?F391ETA?,0*16
!AIVDO,3,1,2,A,81mg>Dh00391ETA?F391ETA?F391ETA?F391ETA?F391ETA?F391ETA?F391,0*3E
!AIVDM,3,2,0,B,ETA=F312ETA=F312ETA=F312ETA=F312ETA=F312ETA=F312ETA=F312ETA=,0*62
!AIVDM,3,3,3,A,F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=,0*15
!AIVDO,3,1,5,A,81mg>L@003E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1,0*65
!AIVDM,3,3,5,A,F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=,0*13
!AIVDO,3,1,4,A,81mg>Ih003A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1,0*4D
!AIVDM,3,3,4,A,F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=,0*12
!AIVDO,3,2,0,B,ETA?F312ETA?F312ETA?F312ETA?F312ETA?F312ETA?F312ETA?F312ETA?,0*60
!AIVDM,3,2,8,A,ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=,0*0A
!AIVDO,3,1,0,B,81mg>@000312ETA?F312ETA?F312ETA?F312ETA?F312ETA?F312ETA?F312,0*68
!AIVDM,3,2,5,A,ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=,0*13
!AIVDO,3,2,2,A,ETA?F391ETA?F391ETA?F391ETA?F391ETA?F391ETA?F391ETA?F391ETA?,0*6A
!AIVDO,3,2,8,A,ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?,0*08
!AIVDM,3,1,9,A,81mg>Uh003U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1,0*4A
!AIVDM,3,3,7,A,F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=,0*11
!AIVDM,3,3,0,A,F311ETA=F311ETA=F311ETA=F311ETA=F311ETA=F311ETA=,0*16
!AIVDO,3,3,1,B,F352ETA?F352ETA?F352ETA?F352ETA?F352ETA?F352ETA?,0*16
!AIVDM,3,1,9,B,81mg>V0003U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2,0*11
!AIVDM,3,1,1,B,81mg>B000352ETA=F352ETA=F352ETA=F352ETA=F352ETA=F352ETA=F352,0*6D
!AIVDM,3,1,2,B,81mg>DP00392ETA=F392ETA=F392ETA=F392ETA=F392ETA=F392ETA=F392,0*04
!AIVDM,3,2,6,B,ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=,0*1C
!AIVDM,3,2,4,A,ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=,0*16
!AIVDO,3,2,4,A,ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?,0*14
!AIVDO,3,2,6,B,ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?,0*1E
!AIVDM,3,3,8,A,F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=,0*1E
!AIVDM,3,1,6,B,81mg>NP003I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2ETA=F3I2,0*7A
!AIVDM,3,3,9,A,F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=F3U1ETA=,0*1F
!AIVDO,3,3,5,B,F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?,0*12
!AIVDM,3,2,1,A,ETA=F351ETA=F351ETA=F351ETA=F351ETA=F351ETA=F351ETA=F351ETA=,0*67
!AIVDO,3,2,1,B,ETA?F352ETA?F352ETA?F352ETA?F352ETA?F352ETA?F352ETA?F352ETA?,0*65
!AIVDM,3,2,7,A,ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=,0*19
!AIVDM,3,1,3,B,81mg>G0003=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2,0*62
!AIVDM,3,1,4,B,81mg>IP003A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2,0*77
!AIVDO,3,1,2,B,81mg>E000392ETA?F392ETA?F392ETA?F392ETA?F392ETA?F392ETA?F392,0*67
!AIVDO,3,3,4,A,F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?F3A1ETA?,0*10
!AIVDO,3,2,0,A,ETA?F311ETA?F311ETA?F311ETA?F311ETA?F311ETA?F311ETA?F311ETA?,0*60
!AIVDO,3,3,6,A,F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?F3I1ETA?,0*12
!AIVDO,3,1,8,A,81mg>Sh003Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1,0*4B
!AIVDO,3,3,8,A,F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?F3Q1ETA?,0*1C
!AIVDO,3,2,3,B,ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?,0*6F
!AIVDO,3,1,9,B,81mg>VP003U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2,0*73
!AIVDM,3,1,5,A,81mg>Kh003E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1ETA=F3E1,0*48
!AIVDO,3,3,7,B,F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?,0*10
!AIVDO,3,3,9,B,F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?F3U2ETA?,0*1E
!AIVDO,3,1,3,B,81mg>GP003=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2,0*00
!AIVDO,3,3,0,A,F311ETA?F311ETA?F311ETA?F311ETA?F311ETA?F311ETA?,0*14
!AIVDO,3,3,6,B,F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?,0*11
!AIVDO,3,1,6,B,81mg>O0003I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2ETA?F3I2,0*19
!AIVDM,3,2,2,A,ETA=F391ETA=F391ETA=F391ETA=F391ETA=F391ETA=F391ETA=F391ETA=,0*68
!AIVDM,3,1,7,B,81mg>Q0003M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2ETA=F3M2,0*00
!AIVDO,3,1,3,A,81mg>G@003=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1,0*10
!AIVDO,3,3,9,A,F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?,0*1D
!AIVDO,3,1,7,A,81mg>Q@003M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1ETA?F3M1,0*72
!AIVDM,3,3,4,B,F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=,0*11
!AIVDM,3,3,1,A,F351ETA=F351ETA=F351ETA=F351ETA=F351ETA=F351ETA=,0*17
!AIVDO,3,1,9,A,81mg>V@003U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1,0*63
!AIVDM,3,1,8,A,81mg>S@003Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1ETA=F3Q1,0*61
!AIVDM,3,3,1,B,F352ETA=F352ETA=F352ETA=F352ETA=F352ETA=F352ETA=,0*14
!AIVDO,3,1,1,B,81mg>BP00352ETA?F352ETA?F352ETA?F352ETA?F352ETA?F352ETA?F352,0*0F
!AIVDO,3,1,1,A,81mg>B@00351ETA?F351ETA?F351ETA?F351ETA?F351ETA?F351ETA?F351,0*1F
!AIVDM,3,2,3,A,ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=,0*6D
!AIVDO,3,2,1,A,ETA?F351ETA?F351ETA?F351ETA?F351ETA?F351ETA?F351ETA?F351ETA?,0*65
!AIVDM,3,2,8,B,ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=,0*0A
!AIVDM,3,3,5,B,F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=,0*10
!AIVDM,3,2,2,B,ETA=F392ETA=F392ETA=F392ETA=F392ETA=F392ETA=F392ETA=F392ETA=,0*68
!AIVDM,3,3,9,B,F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=,0*1C
!AIVDO,3,3,5,A,F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?,0*11
!AIVDM,3,1,4,A,81mg>I@003A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1ETA=F3A1,0*67
!AIVDO,3,1,4,B,81mg>J0003A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2ETA?F3A2,0*16
!AIVDO,3,1,7,B,81mg>QP003M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2ETA?F3M2,0*62
!AIVDM,3,1,3,A,81mg>Fh003=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1ETA=F3=1,0*3B
!AIVDM,3,1,8,B,81mg>SP003Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2ETA=F3Q2,0*71
!AIVDM,3,2,4,B,ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=F3A2ETA=,0*16
!AIVDM,3,2,9,B,ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=F3U2ETA=,0*0F
!AIVDO,3,1,5,B,81mg>LP003E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2ETA?F3E2,0*75
!AIVDO,3,3,3,A,F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?,0*17
!AIVDM,3,2,0,A,ETA=F311ETA=F311ETA=F311ETA=F311ETA=F311ETA=F311ETA=F311ETA=,0*62
!AIVDM,3,2,1,B,ETA=F352ETA=F352ETA=F352ETA=F352ETA=F352ETA=F352ETA=F352ETA=,0*67
!AIVDM,3,1,5,B,81mg>L0003E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2ETA=F3E2,0*17
!AIVDM,3,1,0,B,81mg>?P00312ETA=F312ETA=F312ETA=F312ETA=F312ETA=F312ETA=F312,0*75
!AIVDO,3,2,5,A,ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?F3E1ETA?,0*11
!AIVDO,3,2,3,A,ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?F3=1ETA?,0*6F
!AIVDO,3,2,9,A,ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?F3U1ETA?,0*0D
!AIVDM,3,3,3,B,F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=F3=2ETA=,0*16
!AIVDM,3,1,7,A,81mg>Ph003M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1ETA=F3M1,0*59
!AIVDO,3,2,8,B,ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?F3Q2ETA?,0*08
!AIVDO,3,3,3,B,F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?F3=2ETA?,0*14
!AIVDM,3,3,0,B,F312ETA=F312ETA=F312ETA=F312ETA=F312ETA=F312ETA=,0*15
!AIVDM,2,2,1,A,<?mr4SdWwnh2>rbb,0*50
!AIVDM,2,1,1,A,8h30otA?0@<o;NPPGeCC3oT3m5<UI0QmD00o;NPP,0*0F
!AIVDM,2,2,1,A,Ge31BoGt>580p1kfH00,2*2C

# same sentence received twice
!AIVDM,2,1,1,A,8h30otA?0@<o;NPPGeCC3oT3m5<UI0QmD00o;NPP,0*0F
!AIVDM,2,1,1,A,8h30otA?0@<o;NPPGeCC3oT3m5<UI0QmD00o;NPP,0*0F
!AIVDM,2,2,1,A,Ge31BoGt>580p1kfH00,2*2C

# the first fragment of A was lost
!AIVDM,2,1,1,B,8h30otA?0@<o;NPPGeCC3oT3m5<UI0QmD00o;NPP,0*0F
!AIVDM,2,2,1,A,Ge31BoGt>580p1kfH00,2*2C
!AIVDM,2,2,1,B,Ge31BoGt>580p1kfH00,2*2C

# interleaving keys
!AIVDM,2,1,1,A,8h30otA?0@<o;NPPGeCC3oT3m5<UI0QmD00o;NPP,0*0F
!AIVDM,2,1,1,B,8h30otA?0@<o;NPPGeCC3oT3m5<UI0QmD00o;NPP,0*0F
!AIVDM,2,1,3,A,8h30otA?0@<o;NPPGeCC3oT3m5<UI0QmD00o;NPP,0*0F
!AIVDM,2,1,4,B,8h30otA?0@<o;NPPGeCC3oT3m5<UI0QmD00o;NPP,0*0F
!AIVDM,2,2,1,B,Ge31BoGt>580p1kfH00,2*2C
!AIVDM,2,2,1,A,Ge31BoGt>580p1kfH00,2*2C
!AIVDM,2,2,3,A,Ge31BoGt>580p1kfH00,2*2C
!AIVDM,2,2,4,B,Ge31BoGt>580p1kfH00,2*2C

# This is is in order
\g:2-10-4242*6E\!AIVDM,9,1,7,A,55?MbV02,0*5D
\g:3-10-4242*6F\!AIVDM,9,2,7,A,;H;s<HtK,0*6A
\g:4-10-4242*68\!AIVDM,9,3,7,A,R20EHE:0,0*09
\g:5-10-4242*69\!AIVDM,9,4,7,A,@T4@Dn22,0*56
\g:6-10-4242*6A\!AIVDM,9,5,7,A,22222216,0*1A
\g:7-10-4242*6B\!AIVDM,9,6,7,A,L961O5Gf,0*37
\g:8-10-4242*64\!AIVDM,9,7,7,A,0NSQEp6C,0*23
\g:9-10-4242*65\!AIVDM,9,8,7,A,lRp88888,0*66
\g:10-10-4242*5D\!AIVDM,9,9,7,A,8888880,2*23

# This is in reverse order - should never work
\g:10-10-4242*5D\!AIVDM,9,9,7,A,8888880,2*23
\g:9-10-4242*65\!AIVDM,9,8,7,A,lRp88888,0*66
\g:8-10-4242*64\!AIVDM,9,7,7,A,0NSQEp6C,0*23
\g:7-10-4242*6B\!AIVDM,9,6,7,A,L961O5Gf,0*37
\g:6-10-4242*6A\!AIVDM,9,5,7,A,22222216,0*1A
\g:5-10-4242*69\!AIVDM,9,4,7,A,@T4@Dn22,0*56
\g:4-10-4242*68\!AIVDM,9,3,7,A,R20EHE:0,0*09
\g:3-10-4242*6F\!AIVDM,9,2,7,A,;H;s<HtK,0*6A
\g:2-10-4242*6E\!AIVDM,9,1,7,A,55?MbV02,0*5D

# First frags swapped
\g:3-10-4242*6F\!AIVDM,9,2,7,A,;H;s<HtK,0*6A
\g:2-10-4242*6E\!AIVDM,9,1,7,A,55?MbV02,0*5D
\g:4-10-4242*68\!AIVDM,9,3,7,A,R20EHE:0,0*09
\g:5-10-4242*69\!AIVDM,9,4,7,A,@T4@Dn22,0*56
\g:6-10-4242*6A\!AIVDM,9,5,7,A,22222216,0*1A
\g:7-10-4242*6B\!AIVDM,9,6,7,A,L961O5Gf,0*37
\g:8-10-4242*64\!AIVDM,9,7,7,A,0NSQEp6C,0*23
\g:9-10-4242*65\!AIVDM,9,8,7,A,lRp88888,0*66
\g:10-10-4242*5D\!AIVDM,9,9,7,A,8888880,2*23
59 changes: 23 additions & 36 deletions tests/test_file_stream.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -52,14 +52,13 @@ def test_nmea_sorter_unsorted(self):
output = []
for msg in sorter:
output += msg.raw.splitlines()

self.assertEqual(output, [
b"!AIVDM,1,1,,A,13HOI:0P0000VOHLCnHQKwvL05Ip,0*23",
b"!AIVDM,1,1,,A,133sVfPP00PD>hRMDH@jNOvN20S8,0*7F",
b"!AIVDM,1,1,,B,100h00PP0@PHFV`Mg5gTH?vNPUIp,0*3B",
b"!AIVDM,2,1,1,A,55?MbV02;H;s<HtKR20EHE:0@T4@Dn2222222216L961O5Gf0NSQEp6ClRp8,0*1C",
b"!AIVDM,2,2,1,A,88888888880,2*25",
b"!AIVDM,1,1,,B,23?up2001gGRju>Ap:;R2APP08:c,0*0E",
b"!BSVDM,1,1,,A,15Mj23`PB`o=Of>KjvnJg8PT0L2R,0*7E",
b'!AIVDM,1,1,,A,13HOI:0P0000VOHLCnHQKwvL05Ip,0*23',
b'!AIVDM,1,1,,A,133sVfPP00PD>hRMDH@jNOvN20S8,0*7F',
b'!AIVDM,1,1,,B,100h00PP0@PHFV`Mg5gTH?vNPUIp,0*3B',
b'!AIVDM,1,1,,B,23?up2001gGRju>Ap:;R2APP08:c,0*0E',
b'!BSVDM,1,1,,A,15Mj23`PB`o=Of>KjvnJg8PT0L2R,0*7E',
b'!SAVDM,2,1,4,A,55Mub7P00001L@;SO7TI8DDltqB222222222220O0000067<0620@jhQDTVG,0*43',
b'!SAVDM,2,2,4,A,30H88888880,2*49',
b'!SAVDM,1,1,,B,35Mj2p001qo@5tVKLBWmIDJT01:@,0*33',
Expand All @@ -69,35 +68,27 @@ def test_nmea_sorter_unsorted(self):

def test_sort_with_different_msg_ids(self):
msgs = [
b"!AIVDM,2,2,9,B,888888888888880,2*2E",
b"!AIVDM,2,2,9,B,888888888888880,2*2E", # missing first frag
b"!AIVDM,2,1,9,B,53nFBv01SJ<thHp6220H4heHTf2222222222221?50:454o<`9QSlUDp,0*09",
b'!SAVDM,2,1,4,A,55Mub7P00001L@;SO7TI8DDltqB222222222220O0000067<0620@jhQDTVG,0*43',
b'!SAVDM,2,1,4,A,55Mub7P00001L@;SO7TI8DDltqB222222222220O0000067<0620@jhQDTVG,0*43', # second frag comes later
b'!SAVDM,1,1,,B,35Mj2p001qo@5tVKLBWmIDJT01:@,0*33',
b"!AIVDM,2,2,8,A,88888888880,2*2C",
b"!AIVDM,2,1,1,A,55?MbV02;H;s<HtKR20EHE:0@T4@Dn2222222216L961O5Gf0NSQEp6ClRp8,0*1C",
b"!AIVDM,2,1,8,A,56;OaD02B8EL990b221`P4v1T4pN0HDpN2222216HHN>B6U30A2hCDhD`888,0*4D",
b"!AIVDM,2,2,8,A,88888888880,2*2C", # missing first frag
b"!AIVDM,2,1,1,A,55?MbV02;H;s<HtKR20EHE:0@T4@Dn2222222216L961O5Gf0NSQEp6ClRp8,0*1C", # second frag comes later
b"!AIVDM,2,1,8,A,56;OaD02B8EL990b221`P4v1T4pN0HDpN2222216HHN>B6U30A2hCDhD`888,0*4D", # never completes
b'!SAVDM,2,2,4,A,30H88888880,2*49',
b"!AIVDM,2,2,1,A,88888888880,2*25",
b"!AIVDM,4,4,1,A,88888888880,2*25",
b"!AIVDM,4,3,1,A,88888888880,2*25",
b"!AIVDM,4,2,1,A,88888888880,2*25",
b"!AIVDM,4,1,1,A,88888888880,2*25",
b"!AIVDM,2,2,1,A,88888888880,2*25", # missing first frag
b"!AIVDM,4,4,1,A,88888888880,2*25", # missing first frag
b"!AIVDM,4,3,1,A,88888888880,2*25", # missing first frag
b"!AIVDM,4,2,1,A,88888888880,2*25", # missing first frag
b"!AIVDM,4,1,1,A,88888888880,2*25", # missing first frag
]

expected = [
b"!AIVDM,2,1,9,B,53nFBv01SJ<thHp6220H4heHTf2222222222221?50:454o<`9QSlUDp,0*09",
b"!AIVDM,2,2,9,B,888888888888880,2*2E",
b'!SAVDM,1,1,,B,35Mj2p001qo@5tVKLBWmIDJT01:@,0*33',
b"!AIVDM,2,1,8,A,56;OaD02B8EL990b221`P4v1T4pN0HDpN2222216HHN>B6U30A2hCDhD`888,0*4D",
b"!AIVDM,2,2,8,A,88888888880,2*2C",
b'!SAVDM,2,1,4,A,55Mub7P00001L@;SO7TI8DDltqB222222222220O0000067<0620@jhQDTVG,0*43',
b'!SAVDM,2,2,4,A,30H88888880,2*49',
b"!AIVDM,2,1,1,A,55?MbV02;H;s<HtKR20EHE:0@T4@Dn2222222216L961O5Gf0NSQEp6ClRp8,0*1C",
b"!AIVDM,2,2,1,A,88888888880,2*25",
b"!AIVDM,4,1,1,A,88888888880,2*25",
b"!AIVDM,4,2,1,A,88888888880,2*25",
b"!AIVDM,4,3,1,A,88888888880,2*25",
b"!AIVDM,4,4,1,A,88888888880,2*25",
b'!AIVDM,2,1,1,A,55?MbV02;H;s<HtKR20EHE:0@T4@Dn2222222216L961O5Gf0NSQEp6ClRp8,0*1C',
b'!AIVDM,2,2,1,A,88888888880,2*25'
]

sorter = IterMessages(msgs)
Expand Down Expand Up @@ -225,16 +216,12 @@ def test_timestamp_messages(self):
def test_complex_message_reassembly(self):
"""Ensure that multi fragment messages are reassembled correctly"""
file = pathlib.Path(__file__).parent.joinpath('multi.txt')
for i, msg in enumerate(FileReaderStream(file), 1):
decoded = msg.decode()

key = decoded.data[0:6].decode("ascii")
mmsi = 123456789 + int(key[0]) * 10 + ord(key[1]) + ord(key[2]) + ord(key[3]) + ord(key[4])

assert decoded.mmsi == mmsi
assert decoded.data == b"".join(decoded.data[0:6] for _ in range(20))[:-1]
tot = 0
for msg in FileReaderStream(file):
msg.decode()
tot += 1

assert i == 40
assert tot == 8

def test_frag_num_below_250(self):
result = list(ByteStream([b"!AIVDM,2,-300,4,A,55O0W7`00001L@gCWGA2uItLth@DqtL5@F22220j1h742t0Ht0000000,0*08\n"]))
Expand Down
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