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pythoncrc
Chris Row
Chris Row

Reputation: 51

Calculating CRC using Python zlib.crc32 function

I created a list of size 100 and populated the array with 8bit data in python using the following code and I want to calculate the CRC value using the zlib.crc32() function.

Init_RangenCrc8 = []
for i in range(0,100):
    Init_RangenCrc8.append(random.randrange(0, 255, 1))

crc8_python = zlib.crc32(Init_RangenCrc8, 0xFFFF)

When I return and print the crc8_python, I am not getting any value back.

Any help would be appreciated, thanks.

Upvotes: 0

Views: 12859

Answers (1)

Matt Anderson
Matt Anderson

Reputation: 19759

>>> help(zlib.crc32)
Help on built-in function crc32 in module zlib:

crc32(...)
    crc32(string[, start]) -- Compute a CRC-32 checksum of string.

    An optional starting value can be specified.  The returned checksum is
    a signed integer.
>>> zlib.crc32("".join(chr(random.randrange(0,255)) for _ in xrange(100)))
333158331

EDIT: code that uses the start value 0xFFFF:

>>> text = "".join(chr(random.randrange(0,255)) for _ in xrange(100))

>>> zlib.crc32(text)
-964269250

>>> zlib.crc32(text, 0xFFFF)
2057263175

Upvotes: 7

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