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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2020 Daniel Estevez <daniel@destevez.net>
#
# This file is part of gr-satellites
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
import struct
from gnuradio import gr
import numpy
import pmt
from . import hdlc
class check_crc16_ccitt(gr.basic_block):
"""docstring for block check_crc16_ccitt"""
def __init__(self, verbose):
gr.basic_block.__init__(
self,
name='check_crc16_ccitt',
in_sig=[],
out_sig=[])
self.verbose = verbose
self.message_port_register_in(pmt.intern('in'))
self.set_msg_handler(pmt.intern('in'), self.handle_msg)
self.message_port_register_out(pmt.intern('ok'))
self.message_port_register_out(pmt.intern('fail'))
def handle_msg(self, msg_pmt):
msg = pmt.cdr(msg_pmt)
if not pmt.is_u8vector(msg):
print('[ERROR] Received invalid message type. Expected u8vector')
return
packet = pmt.u8vector_elements(msg)
if len(packet) < 3:
return
packet_out = packet[:-2]
msg_out = pmt.cons(pmt.car(msg_pmt),
pmt.init_u8vector(len(packet_out), packet_out))
crc = hdlc.crc_ccitt(packet_out)
packet_crc = struct.unpack('<H', bytes(packet[-2:]))[0]
if crc == packet_crc:
if self.verbose:
print('CRC OK')
self.message_port_pub(pmt.intern('ok'), msg_out)
else:
if self.verbose:
print('CRC failed')
self.message_port_pub(pmt.intern('fail'), msg_out)
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