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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2017 Daniel Estevez <daniel@destevez.net>
#
# This file is part of gr-satellites
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
import numpy
flag = bytes([0] + 6*[1] + [0])
def crc_ccitt(data):
# Implementation taken from
# hdlc_framer_pb_impl.cc in gr-digital
poly = 0x8408 # reflected 0x1021
crc = 0xffff
for byte in data:
crc ^= byte
for _ in range(8):
crc = (crc >> 1) ^ poly if crc & 1 else crc >> 1
return crc ^ 0xffff
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