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CRCx
=======
Extensive Cyclic Redundancy Check
Work in progress...
Examples
----------
..
Because GitHub doesn't support the include directive the source of
scripts/examples/simple_tcp_server.py has been copied to this file.
.. code:: python
import crc_rc3 as crc
import crc_rc3.catalog
import crc_rc3.engines.generic
import crc_rc3.engines.tableized
import crc_rc3.tables
import zlib
data = b"123456789"
data_a = b"12345"
data_b = b"6789"
check = 0xcbf43926 # crc from crc32 algorithm for the str '123456789
"""
simple usage
select cataloged algorithm
parse your input data
"""
calc = crc.create(crc.catalog.crc_32())
hash_a = calc.calc(data)
"""
calculate from multiple strings of input
via instantiate object from the calculator class
"""
calc = crc.create(crc.catalog.crc_32())
inst = calc()
inst.process(data_a) # process, update
hash_b = inst.final() # you can check the result halfway through the calculation
inst.process(data_b)
hash_c = inst.final() # result, final
# todo check if is big endian
"""
if you need the hash in bytes
big endian
"""
# hash_d = calc.calc_bytes(data)
# or
# hash_e = inst.final_bytes()
"""
create the crc table manually
"""
# table for crc32
table = crc.tables.new_lsbf(0x04c11db7, 32)
# repr it so you can put in your own code
print(crc.tables.table_repr(32, 80)(table))
"""
define your own parameters
option to select engine algorithm
"""
# params for crc32
params = crc.new(
# required
width=32,
poly=0x04c11db7,
init=0xffffffff,
xorout=0xffffffff,
refin=True,
refout=True,
# optional
name="crc32",
aliases=("alias_1", "alias_2"),
desc="description",
table=table, # you can manually insert table here to avoid it being
# calculated automatically every time your program starts
)
calc = crc.create(params)
hash_f = calc.calc(data)
"""
use a different engine
tableized is fastest engine but creates a table of 256 values
this is the default
generic doesn't create a table, but is slower
"""
# engine = crc.engines.generic
engine = crc.engines.tableized
calc = crc.create(params, engine)
hash_g = calc.calc(data)
"""
use the engine directly
no 'convenience objects'
"""
# NotImplemented
"""
test
"""
hashes = check, zlib.crc32(data), hash_a, hash_c, hash_f, hash_g
assert all(h == check for h in hashes)
print(hashes)
if __name__ == '__main__':
pass
Features
--------
...
* 01: ...
Other featues:
* ...
License
-------
CRCx is licensed under `Mozilla Public License`_.
.. External References:
.. _Advanced Climate Systems: http://www.advancedclimate.nl/
.. _GitHub: https://github.com/AdvancedClimateSystems/uModbus/
.. _MODBUS Application Protocol Specification V1.1b3: http://modbus.org/docs/Modbus_Application_Protocol_V1_1b3.pdf
.. _Mozilla Public License: https://github.com/AdvancedClimateSystems/uModbus/blob/develop/LICENSE
.. _Read the Docs: http://umodbus.readthedocs.org/en/latest/
