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62f7561428
* implement hash * fix flake8 error * Update hashes/djb2.py * Update hashes/djb2.py * Long lines * def djb2(s: str) -> int: Co-authored-by: Christian Clauss <cclauss@me.com>
36 lines
871 B
Python
36 lines
871 B
Python
"""
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This algorithm (k=33) was first reported by Dan Bernstein many years ago in comp.lang.c
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Another version of this algorithm (now favored by Bernstein) uses xor:
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hash(i) = hash(i - 1) * 33 ^ str[i];
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First Magic constant 33:
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It has never been adequately explained.
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It's magic because it works better than many other constants, prime or not.
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Second Magic Constant 5381:
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1. odd number
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2. prime number
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3. deficient number
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4. 001/010/100/000/101 b
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source: http://www.cse.yorku.ca/~oz/hash.html
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"""
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def djb2(s: str) -> int:
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"""
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Implementation of djb2 hash algorithm that
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is popular because of it's magic constants.
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>>> djb2('Algorithms')
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3782405311
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>>> djb2('scramble bits')
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1609059040
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"""
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hash = 5381
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for x in s:
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hash = ((hash << 5) + hash) + ord(x)
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return hash & 0xFFFFFFFF
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