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crc16.py
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crc16.py
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#
# Copyright (c) 2019 Nordic Semiconductor ASA
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification,
# are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice, this
# list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice, this
# list of conditions and the following disclaimer in the documentation and/or
# other materials provided with the distribution.
#
# 3. Neither the name of Nordic Semiconductor ASA nor the names of other
# contributors to this software may be used to endorse or promote products
# derived from this software without specific prior written permission.
#
# 4. This software must only be used in or with a processor manufactured by Nordic
# Semiconductor ASA, or in or with a processor manufactured by a third party that
# is used in combination with a processor manufactured by Nordic Semiconductor.
#
# 5. Any software provided in binary or object form under this license must not be
# reverse engineered, decompiled, modified and/or disassembled.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
# ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
# ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
# SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
def calc_crc16(binary_data: bytes, crc=0xffff):
"""
Calculates CRC16 on binary_data
:param int crc: CRC value to start calculation with
:param bytearray binary_data: Array with data to run CRC16 calculation on
:return int: Calculated CRC value of binary_data
"""
for b in binary_data:
crc = (crc >> 8 & 0x00FF) | (crc << 8 & 0xFF00)
crc ^= (crc & 0x00FF) >> 4
crc ^= (crc << 8) << 4
crc ^= ((crc & 0x00FF) << 4) << 1
return crc & 0xFFFF