41 lines
1.3 KiB
C
41 lines
1.3 KiB
C
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/* This is a small program used in order to understand the collison rate
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* of CRC64 (ISO version) VS other stronger hashing functions in the context
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* of hashing keys for the Redis "tracking" feature (client side caching
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* assisted by the server).
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*
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* The program attempts to hash keys with common names in the form of
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*
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* prefix:<counter>
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*
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* And counts the resulting collisons generated in the 24 bits of output
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* needed for the tracking feature invalidation table (16 millions + entries)
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*
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* --------------------------------------------------------------------------
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*
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* Copyright (C) 2019 Salvatore Sanfilippo
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* This code is released under the BSD 2 clause license.
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*/
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <stdio.h>
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#define TABLE_SIZE (1<<24)
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int Table[TABLE_SIZE];
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/* Test the hashing function provided as callback and return the
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* number of collisions found. */
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unsigned long testHashingFunction(uint64_t (*hash)(char *, size_t)) {
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unsigned long collisions = 0;
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memset(Table,0,sizeof(Table));
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char *prefixes[] = {"object", "message", "user", NULL};
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return collisions;
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}
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int main(void) {
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printf("SHA1 : %lu\n", testHashingFunction(sha1Hash));
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printf("CRC64: %lu\n", testHashingFunction(crc64Hash));
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return 0;
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}
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