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Xxh128_hexdigest = xxh3_128_hexdigest Caveats SEED OVERFLOW So we can avoid allocating XXH32/64 state on heap: hexdigest (), 16 ) 17241709254077376921īesides xxh32/xxh64 mentioned above, oneshot functions are also provided, hexdigest () 'ce5087f12470d961'ĭigest() returns bytes of the big-endian representation of the integerĭigest: > import xxhash > h = xxhash.

xxh64 ( 'I want an unsigned 64-bit seed!', seed = 2 ** 64 + 1 ). xxh64 ( 'I want an unsigned 64-bit seed!', seed = 1 ). xxh64 ( 'I want an unsigned 64-bit seed!', seed = 2 ** 64 ). xxh64 ( 'I want an unsigned 64-bit seed!', seed = 0 ). xxh32 ( 'I want an unsigned 32-bit seed!', seed = 2 ** 32 + 1 ). xxh32 ( 'I want an unsigned 32-bit seed!', seed = 1 ). xxh32 ( 'I want an unsigned 32-bit seed!', seed = 2 ** 32 ). xxh32 ( 'I want an unsigned 32-bit seed!', seed = 0 ). Although unsigned integer overflow isĭefined behavior, it’s better not to make it happen: > xxhash. intdigest () 13067679811253438005īe careful that xxh32 takes an unsigned 32-bit integer as seed, while xxh64 digest () TrueĪn optional seed (default is 0) can be used to alter the result predictably: > import xxhash > xxhash. xxh32 ( b 'Nobody inspects the spammish repetition' ).

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update ( b ' the spammish repetition' ) > x. While this module is made hashlib-compliant, intdigest() is also provided toĬonstructors for hash algorithms provided by this module are xxh32() and xxh64().įor example, to obtain the digest of the byte string b'Nobody inspects the spammish repetition': > import xxhash > x = xxhash.

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Regardless of the language used, always try to see if you can simplify the code somehow, in order to make it more maintainable.Md5 digest returns bytes, but the original xxh32 and xxh64 C APIs return integers.Also, you should try to avoid using generic names such as string for naming your variables.I had also recommend not use the += kind of operators when there a is a non trivial expression on the right side, even though this might come down to personal preference.string = text and not str=text (unless specifying default parameters inside a function). Always leave one space when declaring variables.I had recommend putting the code after an if statement on its own line, even if it is only a single statement.# The `-1` is necessary since parity is changed by starting the loop on 1 Untouched lines: items = trailing'.format(text, items) Okay so i did read this question few hours ago on phone and started working out an answer on paper, having the performance tag in mind. We can see that the test you've mentioned in the question passes: $ ipython3 -i test.py # TODO: document the logic behind the checksum calculationsĬhecksum += sum(x + 2 * y if counter % 2 else x * yįor counter, (x, y) in enumerate(iterator)) Also, note that you are reusing the string variable to keep the 'ords' of each character, which, strictly speaking, is not good - the variable name does not correspond to what it is used for.Īt the end you would have something like: DEFAULT_SALT = 'trailing'ĭef get_checksum(part1, part2, salt=DEFAULT_SALT):Ĭombined_string = part1 + part2 + ' ' + salt if part2 != '***' else part1 Variable naming can be improved - str_a, str_b and string are not the best choices (even though the part1 and part2 in the code below are not either - think about what these strings represent - may be you'll come up with better variable names). But, it might become less explicit and potentially a bit more difficult to understand.Ĭomments and docstrings would definitely be needed to describe the logic behind the checksum calculations.

You can use sum() instead of having loop with if and else, which increase the overall nestedness. First of all, I would apply the 'Extract Method' refactoring method and put the logic behind generating a checksum into a get_checksum() function.Īlso, I would avoid hardcoding the trailing 'salt' and the 0x10000 'normalizer' and put them into the default keyword argument value and to a 'constant' respectively.

Python checksum