Merge pull request #29 from GlobalFishingWatch/type-9

add support for type 9

ais_tools/ais.py

@@ -1,6 +1,7 @@
 from ais_tools.transcode import DecodeError
-from ais_tools import ais8
 from ais_tools.transcode import ASCII8toAIS6
+from ais_tools import ais8
+from ais_tools import ais9
 from ais_tools import ais18
 from ais_tools import ais19
 from ais_tools import ais24
@@ -9,6 +10,7 @@
 
 encode_fn = {
     8: ais8.ais8_encode,
+    9: ais9.ais9_encode,
     18: ais18.ais18_encode,
     19: ais19.ais19_encode,
     24: ais24.ais24_encode,
@@ -17,6 +19,7 @@
 
 decode_fn = {
     8: ais8.ais8_decode,
+    9: ais9.ais9_decode,
     18: ais18.ais18_decode,
     19: ais19.ais19_decode,
     24: ais24.ais24_decode,

ais_tools/ais18.py

@@ -1,64 +1,32 @@
-from ais_tools.transcode import DecodeError
 from ais_tools.transcode import NmeaBits
 from ais_tools.transcode import NmeaStruct as Struct
 from ais_tools.transcode import UintField as Uint
 from ais_tools.transcode import Uint10Field as Uint10
 from ais_tools.transcode import LatLonField as LatLon
 from ais_tools.transcode import BoolField as Bool
-from ais_tools.transcode import BitField as Bits
+from ais_tools.ais_commstate import ais_commstate_decode
+from ais_tools.ais_commstate import ais_commstate_encode
+from ais_tools.ais_commstate import ais_commstate_CS
 
 
 def ais18_decode(body, pad):
     bits = NmeaBits.from_nmea(body, pad)
     message = bits.unpack(ais18_fields)
 
-    cs, fields = ais18_commstate_fields(message)
-    message.update(bits.unpack(fields))
-
-    if cs == 'SOTDMA':
-        fields = sotdma_timeout_fields(message)
-        message.update(bits.unpack(fields))
+    ais_commstate_decode(bits, message)
 
     return message
 
 
 def ais18_encode(message):
-    bits = NmeaBits(ais18_fields.nbits + ais18_commstate_CS.nbits)
+    bits = NmeaBits(ais18_fields.nbits + ais_commstate_CS.nbits)
     bits.pack(ais18_fields, message)
 
-    cs, commstate_fields = ais18_commstate_fields(message)
-    timeout_fields = sotdma_timeout_fields(message)
-
-    bits.pack(commstate_fields, message)
-    if cs == 'SOTDMA':
-        bits.pack(timeout_fields, message)
+    ais_commstate_encode(bits, message)
 
     return bits.to_nmea()
 
 
-def ais18_commstate_fields(message):
-    if message.get('unit_flag', 0):
-        return 'CS', ais18_commstate_CS
-    elif message.get('commstate_flag', 0):
-        return 'ITDMA', ais18_commstate_ITDMA
-    else:
-        return 'SOTDMA', ais18_commstate_SOTDMA
-
-
-def sotdma_timeout_fields(message):
-    slot_timeout = message.get('slot_timeout', 0)
-    if slot_timeout == 0:
-        return ais18_commstate_SOTDMA_timeout_0
-    elif slot_timeout == 1:
-        return ais18_commstate_SOTDMA_timeout_1
-    elif slot_timeout in (2, 4, 6):
-        return ais18_commstate_SOTDMA_timeout_2_4_6
-    elif slot_timeout in (3, 5, 7):
-        return ais18_commstate_SOTDMA_timeout_3_5_7
-    else:
-        raise DecodeError(f'AIS18: unknown slot_timeout value {slot_timeout}')
-
-
 ais18_fields = Struct(
     Uint(name='id', nbits=6, default=18),
     Uint(name='repeat_indicator', nbits=2, default=0),
@@ -82,38 +50,3 @@ def sotdma_timeout_fields(message):
     Bool(name='raim', nbits=1, default=0),
     Uint(name='commstate_flag', nbits=1, default=0)
 )
-
-
-ais18_commstate_CS = Struct(
-    Bits(name='commstate', nbits=19, default='1100000000000000110')
-)
-
-ais18_commstate_ITDMA = Struct(
-    Uint(name='sync_state', nbits=2, default=0),
-    Uint(name='slot_increment', nbits=13, default=0),
-    Uint(name='slots_to_allocate', nbits=3, default=0),
-    Bool(name='keep_flag', nbits=1, default=0)
-)
-
-ais18_commstate_SOTDMA = Struct(
-    Uint(name='sync_state', nbits=2, default=0),
-    Uint(name='slot_timeout', nbits=3, default=0),
-)
-
-ais18_commstate_SOTDMA_timeout_0 = Struct(
-    Uint(name='slot_offset', nbits=14, default=0),
-)
-
-ais18_commstate_SOTDMA_timeout_1 = Struct(
-    Uint(name='utc_hour', nbits=5, default=0),
-    Uint(name='utc_min', nbits=7, default=0),
-    Uint(name='utc_spare', nbits=2, default=0),
-)
-
-ais18_commstate_SOTDMA_timeout_2_4_6 = Struct(
-    Uint(name='slot_number', nbits=14, default=0),
-)
-
-ais18_commstate_SOTDMA_timeout_3_5_7 = Struct(
-    Uint(name='received_stations', nbits=14, default=0),
-)

ais_tools/ais19.py

@@ -1,11 +1,9 @@
-from ais_tools.transcode import DecodeError
 from ais_tools.transcode import NmeaBits
 from ais_tools.transcode import NmeaStruct as Struct
 from ais_tools.transcode import UintField as Uint
 from ais_tools.transcode import Uint10Field as Uint10
 from ais_tools.transcode import LatLonField as LatLon
 from ais_tools.transcode import BoolField as Bool
-from ais_tools.transcode import BitField as Bits
 from ais_tools.transcode import ASCII6Field as ASCII6
 
 

ais_tools/ais9.py

@@ -0,0 +1,48 @@
+from ais_tools.transcode import NmeaBits
+from ais_tools.transcode import NmeaStruct as Struct
+from ais_tools.transcode import UintField as Uint
+from ais_tools.transcode import Uint10Field as Uint10
+from ais_tools.transcode import LatLonField as LatLon
+from ais_tools.transcode import BoolField as Bool
+from ais_tools.ais_commstate import ais_commstate_decode
+from ais_tools.ais_commstate import ais_commstate_encode
+from ais_tools.ais_commstate import ais_commstate_CS
+
+
+def ais9_decode(body, pad):
+    bits = NmeaBits.from_nmea(body, pad)
+    message = bits.unpack(ais9_fields)
+
+    ais_commstate_decode(bits, message)
+
+    return message
+
+
+def ais9_encode(message):
+    bits = NmeaBits(ais9_fields.nbits + ais_commstate_CS.nbits)
+    bits.pack(ais9_fields, message)
+
+    ais_commstate_encode(bits, message)
+
+    return bits.to_nmea()
+
+
+ais9_fields = Struct(
+    Uint(name='id', nbits=6, default=18),
+    Uint(name='repeat_indicator', nbits=2, default=0),
+    Uint(name='mmsi', nbits=30),
+    Uint(name='alt', nbits=12, default=4095),
+    Uint(name='sog', nbits=10, default=1023),
+    Uint(name='position_accuracy', nbits=1, default=0),
+    LatLon(name='x', nbits=28, default=181),
+    LatLon(name='y', nbits=27, default=91),
+    Uint10(name='cog', nbits=12, default=360),
+    Uint(name='timestamp', nbits=6, default=60),
+    Uint(name='alt_sensor', nbits=1, default=0),
+    Uint(name='spare', nbits=7, default=0),
+    Uint(name='dte', nbits=1, default=0),
+    Uint(name='spare2', nbits=3, default=0),
+    Bool(name='assigned_mode', nbits=1, default=0),
+    Bool(name='raim', nbits=1, default=0),
+    Uint(name='commstate_flag', nbits=1, default=0)
+)

ais_tools/ais_commstate.py

@@ -0,0 +1,81 @@
+from ais_tools.transcode import DecodeError
+from ais_tools.transcode import UintField as Uint
+from ais_tools.transcode import BitField as Bits
+from ais_tools.transcode import NmeaStruct as Struct
+from ais_tools.transcode import BoolField as Bool
+
+
+def ais_commstate_decode(bits, message):
+    cs, fields = ais_commstate_fields(message)
+    message.update(bits.unpack(fields))
+
+    if cs == 'SOTDMA':
+        fields = sotdma_timeout_fields(message)
+        message.update(bits.unpack(fields))
+
+
+def ais_commstate_encode(bits, message):
+    cs, commstate_fields = ais_commstate_fields(message)
+    timeout_fields = sotdma_timeout_fields(message)
+
+    bits.pack(commstate_fields, message)
+    if cs == 'SOTDMA':
+        bits.pack(timeout_fields, message)
+
+
+def ais_commstate_fields(message):
+    if message.get('unit_flag', 0):
+        return 'CS', ais_commstate_CS
+    elif message.get('commstate_flag', 0):
+        return 'ITDMA', ais_commstate_ITDMA
+    else:
+        return 'SOTDMA', ais_commstate_SOTDMA
+
+
+def sotdma_timeout_fields(message):
+    slot_timeout = message.get('slot_timeout', 0)
+    if slot_timeout == 0:
+        return ais_commstate_SOTDMA_timeout_0
+    elif slot_timeout == 1:
+        return ais_commstate_SOTDMA_timeout_1
+    elif slot_timeout in (2, 4, 6):
+        return ais_commstate_SOTDMA_timeout_2_4_6
+    elif slot_timeout in (3, 5, 7):
+        return ais_commstate_SOTDMA_timeout_3_5_7
+    else:
+        raise DecodeError(f'AIS18: unknown slot_timeout value {slot_timeout}')
+
+
+ais_commstate_CS = Struct(
+    Bits(name='commstate', nbits=19, default='1100000000000000110')
+)
+
+ais_commstate_ITDMA = Struct(
+    Uint(name='sync_state', nbits=2, default=0),
+    Uint(name='slot_increment', nbits=13, default=0),
+    Uint(name='slots_to_allocate', nbits=3, default=0),
+    Bool(name='keep_flag', nbits=1, default=0)
+)
+
+ais_commstate_SOTDMA = Struct(
+    Uint(name='sync_state', nbits=2, default=0),
+    Uint(name='slot_timeout', nbits=3, default=0),
+)
+
+ais_commstate_SOTDMA_timeout_0 = Struct(
+    Uint(name='slot_offset', nbits=14, default=0),
+)
+
+ais_commstate_SOTDMA_timeout_1 = Struct(
+    Uint(name='utc_hour', nbits=5, default=0),
+    Uint(name='utc_min', nbits=7, default=0),
+    Uint(name='utc_spare', nbits=2, default=0),
+)
+
+ais_commstate_SOTDMA_timeout_2_4_6 = Struct(
+    Uint(name='slot_number', nbits=14, default=0),
+)
+
+ais_commstate_SOTDMA_timeout_3_5_7 = Struct(
+    Uint(name='received_stations', nbits=14, default=0),
+)

sample/type8.nmea

@@ -0,0 +1,2 @@
+!AIVDM,1,1,,B,8Nj<9D0000ttt0<D04@<tt<8`H0H@@l44L`<40<@tT`<4T0`=h0,2*47
+

tests/test_ais.py

@@ -16,7 +16,8 @@
     ('H>cSnNP@4eEL544000000000000', 2, {}),
     ('H>cSnNTU7B=40058qpmjhh000004', 0, {'spare'}),
     ('I0000027FtlE01000VNJ;0`:h`0', 5, {}),
-    ('C7m@5n004qtr0wtdVL9GSwrPFK04BL`2L?042@2>B310?1052120', 0, {'assigned_mode'})
+    ('C7m@5n004qtr0wtdVL9GSwrPFK04BL`2L?042@2>B310?1052120', 0, {'assigned_mode'}),
+    ('9001?BP=h:qJ9vb;:f7EN1h240Rb', 0, {})
 ])
 def test_nmea_vs_libais(body, pad, ignore):
     is_close_fields = {'x', 'y', 'cog', 'sog'}
@@ -80,6 +81,17 @@ def test_ais8_wrong_pad():
     assert ('83am8S@j<d8dtfMEuj9loFOM6@0', 2) == AISMessageTranscoder.encode_nmea(msg)
 
 
+@pytest.mark.parametrize("body,pad,expected", [
+    ('9001?BP=h:qJ9vb;:f7EN1h240Rb', 0, {'mmsi': 20298, 'alt': 55, 'sog': 10}),
+    ('90009C3dRIM1QSsjSPAa1;h200T4', 0, {'mmsi': 2380, 'alt': 946, 'alt_sensor': 0}),
+])
+def test_ais9(body, pad, expected):
+    msg = AISMessageTranscoder.decode_nmea(body, pad)
+    actual = {k: v for k, v in msg.items() if k in expected}
+    assert actual == expected
+    assert AISMessageTranscoder.encode_nmea(msg) == (body, pad)
+
+
 @pytest.mark.parametrize("body,pad,expected", [
     ('B:U=ai@09o>61WLb:orRv2010400', 0, {'unit_flag': 0, 'commstate_flag': 0, 'slot_timeout': 1}),
     ('B52T:q@1C6TOpsUj5@??owTQh85G', 0, {'unit_flag': 0, 'commstate_flag': 0, 'slot_timeout': 2}),
@@ -102,14 +114,15 @@ def test_ais18(body, pad, expected):
 
 @pytest.mark.parametrize("body,pad,expected", [
     ('C8k?R4h06mc;FwrwlfQWpTv0PBL>`2BTNL?WSWKQ1gW:00411R2P', 0, {'name': 'PINGTAIRONG313-0 73%'}),
-    ('C8kI2<004V0u6wsPwKH00Qv0PBL>`2BTNL?gkKW1eg:000411R2P',0, {'assigned_mode': False})
+    ('C8kI2<004V0u6wsPwKH00Qv0PBL>`2BTNL?gkKW1eg:000411R2P', 0, {'assigned_mode': False})
 ])
 def test_ais19(body, pad, expected):
     msg = AISMessageTranscoder.decode_nmea(body, pad)
     actual = {k: v for k, v in msg.items() if k in expected}
     assert actual == expected
     assert AISMessageTranscoder.encode_nmea(msg) == (body, pad)
 
+
 @pytest.mark.parametrize("fields", [
     {'part_num': 0, 'name': 'ABCDEFGHIJKLMNOP@@@@'},
     {'part_num': 1, 'vendor_id_1371_4': 'GRM'},

tests/test_aivdm.py

@@ -15,7 +15,9 @@
     ('\\s:66,c:1661782483*3E\\!AIVDM,1,1,,A,35DFuH002>9NHLHCE@MB@AqD07VS,0*57', {'raim': False}),
     ('\\s:66,c:1661782099*31\\!AIVDM,1,1,,A,33`mOp0P0n0FNg6Mv7seTwvP0S0S,0*5C', {'keep_flag': True}),
     ('\\s:66,c:1662392695*3D\\!AIVDM,1,1,,A,E>j9dQjas000000000000000000@Ijfb?VJlh00808v>B0,4*0D',
-       {'assigned_mode': False})
+        {'assigned_mode': False}),
+    ('\\s:66,c:1663246931*35\\!AIVDM,1,1,,,9001?BP=h:qJ9vb;:f7EN1h240Rb,0*3F',
+        {'alt_sensor': 0, 'assigned_mode': False})
 ])
 def test_decode(nmea, expected):
     decoder = AIVDM()