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- '''MAVLink X25 CRC code'''
- from builtins import object
- class x25crc(object):
- '''x25 CRC - based on checksum.h from mavlink library'''
- def __init__(self, buf=None):
- self.crc = 0xffff
- if buf is not None:
- if isinstance(buf, str):
- self.accumulate_str(buf)
- else:
- self.accumulate(buf)
- def accumulate(self, buf):
- '''add in some more bytes'''
- accum = self.crc
- for b in buf:
- tmp = b ^ (accum & 0xff)
- tmp = (tmp ^ (tmp<<4)) & 0xFF
- accum = (accum>>8) ^ (tmp<<8) ^ (tmp<<3) ^ (tmp>>4)
- self.crc = accum
- def accumulate_str(self, buf):
- '''add in some more bytes'''
- accum = self.crc
- import array
- bytes = array.array('B')
- bytes.fromstring(buf)
- self.accumulate(bytes)
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