BW3-Core/boswatch/decoder/pocsag.py

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2018-01-07 14:09:40 +01:00
#!/usr/bin/python
# -*- coding: utf-8 -*-
"""!
____ ____ ______ __ __ __ _____
/ __ )/ __ \/ ___/ | / /___ _/ /______/ /_ |__ /
/ __ / / / /\__ \| | /| / / __ `/ __/ ___/ __ \ /_ <
/ /_/ / /_/ /___/ /| |/ |/ / /_/ / /_/ /__/ / / / ___/ /
/_____/\____//____/ |__/|__/\__,_/\__/\___/_/ /_/ /____/
German BOS Information Script
by Bastian Schroll
@file: pocsag.py
@date: 06.01.2018
@author: Bastian Schroll
@description: Decoder class for pocsag
"""
import logging
import re
from boswatch.packet import packet
logging.debug("- %s loaded", __name__)
class Pocsag:
"""!POCSAG decoder class
This class decodes POCSAG data.
First step is to validate the data and check if the format is correct.
In the last step a valid BOSWatch packet is created and returned"""
def __init__(self):
"""!Create a new instance"""
logging.debug("POCSAG decoder started")
def decode(self, data):
"""!Decodes POCSAG
@param data: POCSAG for decoding
@return BOSWatch POCSAG packet or None"""
bitrate = None
ric = None
subric = None
if "POCSAG512:" in data:
bitrate = 512
ric = data[20:27].replace(" ", "").zfill(7)
subric = str(int(data[39]) + 1)
elif "POCSAG1200:" in data:
bitrate = 1200
ric = data[21:28].replace(" ", "").zfill(7)
subric = str(int(data[40]) + 1)
elif "POCSAG2400:" in data:
bitrate = 2400
ric = data[21:28].replace(" ", "").zfill(7)
subric = str(int(data[40]) + 1)
if re.search("[0-9]{7}", ric) and re.search("[1-4]{1}", subric):
if "Alpha:" in data:
message = data.split('Alpha: ')[1].strip()
message = message.replace('<NUL><NUL>', '').replace('<NUL>', '').replace('<NUL', '').replace('< NUL>', '').replace('<EOT>', '').strip()
else:
message = ""
subricText = subric.replace("1", "a").replace("2", "b").replace("3", "c").replace("4", "d")
logging.debug("found valid POCSAG")
bwPacket = packet.Packet()
bwPacket.setField("mode", "pocsag")
bwPacket.setField("bitrate", bitrate)
bwPacket.setField("ric", ric)
bwPacket.setField("subric", subric)
bwPacket.setField("subricText", subricText)
bwPacket.setField("message", message)
logging.debug(bwPacket)
return bwPacket
logging.warning("no valid data")
return None