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Update crc comparison to use int datatype #80

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Update crc comparison to use int datatype #80

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8dab307
Update crc comparison to use int datatype
gwolffblues Nov 17, 2023
e8aea90
Added spaces after comment indicator
gwolffblues Nov 17, 2023
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16 changes: 11 additions & 5 deletions notecard/notecard.py
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Original file line number Diff line number Diff line change
Expand Up @@ -168,7 +168,9 @@ def _crc_error(self, rsp_bytes):
# the decoding process. When re-encoded, the string representation is
# also truncated, and so the CRC will be computed over a different
# string than was originally sent, resulting in a CRC error.
seq_number, crc = rsp_json['crc'].split(':')
seq_number_str, crc_str = rsp_json['crc'].split(':')
seq_number = int(seq_number_str,16)
crc = int(crc_str, 16)
# Remove the 'crc' field from the response.
rsp_str = rsp_bytes.decode()
rsp_str_crc_removed = rsp_str.split('"crc":')[0]
Expand All @@ -179,17 +181,21 @@ def _crc_error(self, rsp_bytes):

# Compute the CRC over the response, with the 'crc' field removed.
bytes_for_crc = rsp_str_crc_removed.encode('utf-8')
computed_crc = '{:08x}'.format(crc32(bytes_for_crc)).upper()
expected_seq_number = '{:04x}'.format(self._last_request_seq_number)
# computed_crc = '{:08x}'.format(crc32(bytes_for_crc)).upper()
computed_crc = crc32(bytes_for_crc)
# expected_seq_number = '{:04x}'.format(self._last_request_seq_number).upper()
expected_seq_number = self._last_request_seq_number

if seq_number != expected_seq_number:
if self._debug:
expected_seq_str = '{:04x}'.format(expected_seq_number)
print('Sequence number mismatch. Expected ' + \
f'{expected_seq_number}, received {seq_number}.')
f'{expected_seq_str}, received {seq_number_str}.')
return True
elif crc != computed_crc:
if self._debug:
print(f'CRC error. Computed {computed_crc}, received {crc}.')
computed_crc_str = '{:08x}'.format(computed_crc).upper()
print(f'CRC error. Computed {computed_crc_str}, received {crc_str}.')
return True

return False
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