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import re
import math
from aprslib import base91
from aprslib.exceptions import ParseError
from aprslib.parsing.common import parse_dao
from aprslib.parsing.telemetry import parse_comment_telemetry
__all__ = [
'parse_mice',
]
# Mic-e message type table
MTYPE_TABLE_STD = {
"111": "M0: Off Duty",
"110": "M1: En Route",
"101": "M2: In Service",
"100": "M3: Returning",
"011": "M4: Committed",
"010": "M5: Special",
"001": "M6: Priority",
"000": "Emergency",
}
MTYPE_TABLE_CUSTOM = {
"111": "C0: Custom-0",
"110": "C1: Custom-1",
"101": "C2: Custom-2",
"100": "C3: Custom-3",
"011": "C4: Custom-4",
"010": "C5: Custom-5",
"001": "C6: Custom-6",
"000": "Emergency",
}
# Mic-encoded packet
#
# 'lllc/s$/......... Mic-E no message capability
# 'lllc/s$/>........ Mic-E message capability
# `lllc/s$/>........ Mic-E old posit
def parse_mice(dstcall, body):
parsed = {'format': 'mic-e'}
dstcall = dstcall.split('-')[0]
# verify mic-e format
if len(dstcall) != 6:
raise ParseError("dstcall has to be 6 characters")
if len(body) < 8:
raise ParseError("packet data field is too short")
if not re.match(r"^[0-9A-Z]{3}[0-9L-Z]{3}$", dstcall):
raise ParseError("invalid dstcall")
if not re.match(r"^[&-\x7f][&-a][\x1c-\x7f]{2}[\x1c-\x7d]"
r"[\x1c-\x7f][\x21-\x7e][\/\\0-9A-Z]", body):
raise ParseError("invalid data format")
# get symbol table and symbol
parsed.update({
'symbol': body[6],
'symbol_table': body[7]
})
# parse latitude
# the routine translates each characters into a lat digit as described in
# 'Mic-E Destination Address Field Encoding' table
tmpdstcall = ""
for i in dstcall:
if i in "KLZ": # spaces
tmpdstcall += " "
elif ord(i) > 76: # P-Y
tmpdstcall += chr(ord(i) - 32)
elif ord(i) > 57: # A-J
tmpdstcall += chr(ord(i) - 17)
else: # 0-9
tmpdstcall += i
# determine position ambiguity
match = re.findall(r"^\d+( *)$", tmpdstcall)
if not match:
raise ParseError("invalid latitude ambiguity")
posambiguity = len(match[0])
parsed.update({
'posambiguity': posambiguity
})
# adjust the coordinates be in center of ambiguity box
tmpdstcall = list(tmpdstcall)
if posambiguity > 0:
if posambiguity >= 4:
tmpdstcall[2] = '3'
else:
tmpdstcall[6 - posambiguity] = '5'
tmpdstcall = "".join(tmpdstcall)
latminutes = float(("%s.%s" % (tmpdstcall[2:4], tmpdstcall[4:6])).replace(" ", "0"))
latitude = int(tmpdstcall[0:2]) + (latminutes / 60.0)
# determine the sign N/S
latitude = -latitude if ord(dstcall[3]) <= 0x4c else latitude
parsed.update({
'latitude': latitude
})
# parse message bits
mbits = re.sub(r"[0-9L]", "0", dstcall[0:3])
mbits = re.sub(r"[P-Z]", "1", mbits)
mbits = re.sub(r"[A-K]", "2", mbits)
parsed.update({
'mbits': mbits
})
# resolve message type
if mbits.find("2") > -1:
parsed.update({
'mtype': MTYPE_TABLE_CUSTOM[mbits.replace("2", "1")]
})
else:
parsed.update({
'mtype': MTYPE_TABLE_STD[mbits]
})
# parse longitude
longitude = ord(body[0]) - 28 # decimal part of longitude
longitude += 100 if ord(dstcall[4]) >= 0x50 else 0 # apply lng offset
longitude += -80 if longitude >= 180 and longitude <= 189 else 0
longitude += -190 if longitude >= 190 and longitude <= 199 else 0
# long minutes
lngminutes = ord(body[1]) - 28.0
lngminutes += -60 if lngminutes >= 60 else 0
# + (long hundredths of minutes)
lngminutes += ((ord(body[2]) - 28.0) / 100.0)
# apply position ambiguity
# routines adjust longitude to center of the ambiguity box
if posambiguity == 4:
lngminutes = 30
elif posambiguity == 3:
lngminutes = (math.floor(lngminutes/10) + 0.5) * 10
elif posambiguity == 2:
lngminutes = math.floor(lngminutes) + 0.5
elif posambiguity == 1:
lngminutes = (math.floor(lngminutes*10) + 0.5) / 10.0
elif posambiguity != 0:
raise ParseError("Unsupported position ambiguity: %d" % posambiguity)
longitude += lngminutes / 60.0
# apply E/W sign
longitude = 0 - longitude if ord(dstcall[5]) >= 0x50 else longitude
parsed.update({
'longitude': longitude
})
# parse speed and course
speed = (ord(body[3]) - 28) * 10
course = ord(body[4]) - 28
quotient = int(course / 10.0)
course += -(quotient * 10)
course = course*100 + ord(body[5]) - 28
speed += quotient
speed += -800 if speed >= 800 else 0
course += -400 if course >= 400 else 0
speed *= 1.852 # knots * 1.852 = kmph
parsed.update({
'speed': speed,
'course': course
})
# the rest of the packet can contain telemetry and comment
if len(body) > 8:
body = body[8:]
# check for optional 2 or 5 channel telemetry
match = re.findall(r"^('[0-9a-f]{10}|`[0-9a-f]{4})(.*)$", body)
if match:
hexdata, body = match[0]
hexdata = hexdata[1:] # remove telemtry flag
channels = int(len(hexdata) / 2) # determine number of channels
hexdata = int(hexdata, 16) # convert hex to int
telemetry = []
for i in range(channels):
telemetry.insert(0, int(hexdata >> 8*i & 255))
parsed.update({'telemetry': telemetry})
# check for optional altitude
match = re.findall(r"^(.*)([!-{]{3})\}(.*)$", body)
if match:
body, altitude, extra = match[0]
altitude = base91.to_decimal(altitude) - 10000
parsed.update({'altitude': altitude})
body = body + extra
# attempt to parse comment telemetry
body, telemetry = parse_comment_telemetry(body)
parsed.update(telemetry)
# parse DAO extention
body = parse_dao(body, parsed)
# rest is a comment
parsed.update({'comment': body.strip(' ')})
return ('', parsed)
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