hphp/util/hash.cpp

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16 #include "hphp/util/hash.h"
  17 #include <folly/CpuId.h>
  18
  19 namespace HPHP {
  20
  21 bool IsHWHashSupported() {
  22 #ifdef USE_HWCRC
  23 #if defined __SSE4_2__
  24   return true;
  25 #else
  26   static folly::CpuId cpuid;
  27   return cpuid.sse42();
  28 #endif
  29 #else
  30   return false;
  31 #endif
  32 }
  33
  34 #if !defined(USE_HWCRC) || !(defined(__SSE4_2__) || \
  35                              defined(ENABLE_AARCH64_CRC))
  36 NEVER_INLINE
  37 strhash_t hash_string_cs_fallback(const char *arKey, uint32_t nKeyLength) {
  38 #ifdef USE_HWCRC
  39   if (IsHWHashSupported()) {
  40     return hash_string_cs_unaligned_crc(arKey, nKeyLength);
  41   }
  42 #endif
  43   uint64_t h[2];
  44   MurmurHash3::hash128<true>(arKey, nKeyLength, 0, h);
  45   return strhash_t(h[0] & STRHASH_MASK);
  46 }
  47
  48 NEVER_INLINE
  49 strhash_t hash_string_i_fallback(const char *arKey, uint32_t nKeyLength) {
  50 #ifdef USE_HWCRC
  51   if (IsHWHashSupported()) {
  52     return hash_string_i_unaligned_crc(arKey, nKeyLength);
  53   }
  54 #endif
  55   uint64_t h[2];
  56   MurmurHash3::hash128<false>(arKey, nKeyLength, 0, h);
  57   return strhash_t(h[0] & STRHASH_MASK);
  58 }
  59
  60 #endif
  61
  62 }