git.m6w6.name Git - awesomized/libmemcached/blob - libhashkit/fnv.c

   1 /* HashKit
   2  * Copyright (C) 2009 Brian Aker
   3  * All rights reserved.
   4  *
   5  * Use and distribution licensed under the BSD license.  See
   6  * the COPYING file in the parent directory for full text.
   7  */
   8
   9 #include "common.h"
  10
  11 /* FNV hash'es lifted from Dustin Sallings work */
  12 static uint64_t FNV_64_INIT= UINT64_C(0xcbf29ce484222325);
  13 static uint64_t FNV_64_PRIME= UINT64_C(0x100000001b3);
  14 static uint32_t FNV_32_INIT= 2166136261UL;
  15 static uint32_t FNV_32_PRIME= 16777619;
  16
  17 uint32_t hashkit_fnv1_64(const char *key, size_t key_length, void *context __attribute__((unused)))
  18 {
  19   /* Thanks to pierre@demartines.com for the pointer */
  20   uint64_t hash= FNV_64_INIT;
  21
  22   for (size_t x= 0; x < key_length; x++)
  23   {
  24     hash *= FNV_64_PRIME;
  25     hash ^= (uint64_t)key[x];
  26   }
  27
  28   return (uint32_t)hash;
  29 }
  30
  31 uint32_t hashkit_fnv1a_64(const char *key, size_t key_length, void *context __attribute__((unused)))
  32 {
  33   uint32_t hash= (uint32_t) FNV_64_INIT;
  34
  35   for (size_t x= 0; x < key_length; x++)
  36   {
  37     uint32_t val= (uint32_t)key[x];
  38     hash ^= val;
  39     hash *= (uint32_t) FNV_64_PRIME;
  40   }
  41
  42   return hash;
  43 }
  44
  45 uint32_t hashkit_fnv1_32(const char *key, size_t key_length, void *context __attribute__((unused)))
  46 {
  47   uint32_t hash= FNV_32_INIT;
  48
  49   for (size_t x= 0; x < key_length; x++)
  50   {
  51     uint32_t val= (uint32_t)key[x];
  52     hash *= FNV_32_PRIME;
  53     hash ^= val;
  54   }
  55
  56   return hash;
  57 }
  58
  59 uint32_t hashkit_fnv1a_32(const char *key, size_t key_length, void *context __attribute__((unused)))
  60 {
  61   uint32_t hash= FNV_32_INIT;
  62
  63   for (size_t x= 0; x < key_length; x++)
  64   {
  65     uint32_t val= (uint32_t)key[x];
  66     hash ^= val;
  67     hash *= FNV_32_PRIME;
  68   }
  69
  70   return hash;
  71 }