release/src/router/nginx/src/core/ngx_murmurhash.c

   1
   2 /*
   3  * Copyright (C) Austin Appleby
   4  */
   5
   6
   7 #include <ngx_config.h>
   8 #include <ngx_core.h>
   9
  10
  11 uint32_t
  12 ngx_murmur_hash2(u_char *data, size_t len)
  13 {
  14     uint32_t  h, k;
  15
  16     h = 0 ^ len;
  17
  18     while (len >= 4) {
  19         k  = data[0];
  20         k |= data[1] << 8;
  21         k |= data[2] << 16;
  22         k |= data[3] << 24;
  23
  24         k *= 0x5bd1e995;
  25         k ^= k >> 24;
  26         k *= 0x5bd1e995;
  27
  28         h *= 0x5bd1e995;
  29         h ^= k;
  30
  31         data += 4;
  32         len -= 4;
  33     }
  34
  35     switch (len) {
  36     case 3:
  37         h ^= data[2] << 16;
  38     case 2:
  39         h ^= data[1] << 8;
  40     case 1:
  41         h ^= data[0];
  42         h *= 0x5bd1e995;
  43     }
  44
  45     h ^= h >> 13;
  46     h *= 0x5bd1e995;
  47     h ^= h >> 15;
  48
  49     return h;
  50 }