Python/hashes/adler32.py

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"""
Adler-32 is a checksum algorithm which was invented by Mark Adler in 1995.
Compared to a cyclic redundancy check of the same length, it trades reliability for
speed (preferring the latter).
Adler-32 is more reliable than Fletcher-16, and slightly less reliable than
Fletcher-32.[2]
source: https://en.wikipedia.org/wiki/Adler-32
"""
def adler32(plain_text: str) -> int:
"""
Function implements adler-32 hash.
Iterates and evaluates a new value for each character
>>> adler32('Algorithms')
363791387
>>> adler32('go adler em all')
708642122
"""
MOD_ADLER = 65521 # noqa: N806
a = 1
b = 0
for plain_chr in plain_text:
a = (a + ord(plain_chr)) % MOD_ADLER
b = (b + a) % MOD_ADLER
return (b << 16) | a