lighttpd 1.4.x
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43 lines
1.3 KiB
43 lines
1.3 KiB
/* algo_md.h - message digest (MD) wrapper (non-cryptographic) |
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* |
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* Copyright(c) 2020 Glenn Strauss gstrauss()gluelogic.com All rights reserved |
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* License: BSD 3-clause (same as lighttpd) |
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*/ |
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#ifndef INCLUDED_ALGO_MD_H |
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#define INCLUDED_ALGO_MD_H |
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#include "first.h" |
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/* |
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* not cryptographically secure (and never intended to be) |
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*/ |
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/* DJB hash function for strings (djb2a) */ |
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#define DJBHASH_INIT 5381 |
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__attribute_pure__ |
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static inline uint32_t djbhash(const char *str, const uint32_t len, uint32_t hash); |
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static inline uint32_t djbhash(const char *str, const uint32_t len, uint32_t hash) |
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{ |
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const unsigned char * const s = (const unsigned char *)str; |
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for (uint32_t i = 0; i < len; ++i) hash = ((hash << 5) + hash) ^ s[i]; |
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return hash; |
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} |
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/* Donald E. Knuth |
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* The Art Of Computer Programming Volume 3 |
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* Chapter 6.4, Topic: Sorting and Search */ |
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/*(len should be passed as initial hash value. |
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* On subsequent calls, pass intermediate hash value for incremental hashing)*/ |
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__attribute_pure__ |
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static inline uint32_t dekhash (const char *str, const uint32_t len, uint32_t hash); |
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static inline uint32_t dekhash (const char *str, const uint32_t len, uint32_t hash) |
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{ |
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const unsigned char * const s = (const unsigned char *)str; |
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for (uint32_t i = 0; i < len; ++i) hash = (hash << 5) ^ (hash >> 27) ^ s[i]; |
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return hash; |
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} |
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#endif /* INCLUDED_ALGO_MD_H */
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