49 lines
1.3 KiB
C
49 lines
1.3 KiB
C
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/*
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* Copyright (c) 1991, Daniel J. Bernstein
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/*
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* This software is in the PD as of approximately 2007. The story
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* behind it (and other DJB software) is quite amazing. Thanks Dan!!
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*
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* Many distributors have relicensed it under e.g. BSD, MIT, and others.
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*
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* It is not clear what the original license name is or how to declare it
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* using SPDX terms, since it explicitly has no license. I think it makes
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* sense to use the default Zephyr licensing.
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*
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* Note: this is not a cryptographically strong hash algorithm.
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*
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* For details, please see
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* https://cr.yp.to/rights.html
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* https://cr.yp.to/distributors.html
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* http://thedjbway.b0llix.net/license_free.html
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*
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* https://groups.google.com/g/comp.lang.c/c/lSKWXiuNOAk
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* https://theartincode.stanis.me/008-djb2/
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* http://www.cse.yorku.ca/~oz/hash.html
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* https://bit.ly/3IxUVvC
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*/
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#include <stddef.h>
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#include <stdint.h>
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#include <zephyr/sys/hash_function.h>
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uint32_t sys_hash32_djb2(const void *str, size_t n)
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{
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uint32_t hash;
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const uint8_t *d;
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/* The number 5381 is the initializer for the djb2 hash */
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for (hash = 5381, d = str; n > 0; --n, ++d) {
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/* The djb2 hash multiplier is 33 (i.e. 2^5 + 1) */
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hash = (hash << 5) + hash;
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hash ^= *d;
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}
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return hash;
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}
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