git.m6w6.name Git - m6w6/libmemcached/blob - src/libhashkit/fnv_32.cc

   1 /*
   2     +--------------------------------------------------------------------+
   3     | libmemcached - C/C++ Client Library for memcached                  |
   4     +--------------------------------------------------------------------+
   5     | Redistribution and use in source and binary forms, with or without |
   6     | modification, are permitted under the terms of the BSD license.    |
   7     | You should have received a copy of the license in a bundled file   |
   8     | named LICENSE; in case you did not receive a copy you can review   |
   9     | the terms online at: https://opensource.org/licenses/BSD-3-Clause  |
  10     +--------------------------------------------------------------------+
  11     | Copyright (c) 2006-2014 Brian Aker   https://datadifferential.com/ |
  12     | Copyright (c) 2020 Michael Wallner   <mike@php.net>                |
  13     +--------------------------------------------------------------------+
  14 */
  15
  16 #include "libhashkit/common.h"
  17
  18 /* FNV hash'es lifted from Dustin Sallings work */
  19 static uint32_t FNV_32_INIT = 2166136261UL;
  20 static uint32_t FNV_32_PRIME = 16777619;
  21
  22 uint32_t hashkit_fnv1_32(const char *key, size_t key_length, void *context) {
  23   uint32_t hash = FNV_32_INIT;
  24   (void) context;
  25
  26   for (size_t x = 0; x < key_length; x++) {
  27     uint32_t val = (uint32_t) key[x];
  28     hash *= FNV_32_PRIME;
  29     hash ^= val;
  30   }
  31
  32   return hash;
  33 }
  34
  35 uint32_t hashkit_fnv1a_32(const char *key, size_t key_length, void *context) {
  36   uint32_t hash = FNV_32_INIT;
  37   (void) context;
  38
  39   for (size_t x = 0; x < key_length; x++) {
  40     uint32_t val = (uint32_t) key[x];
  41     hash ^= val;
  42     hash *= FNV_32_PRIME;
  43   }
  44
  45   return hash;
  46 }