ceph/src/rocksdb/util/murmurhash.h

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under the BSD-style license found in the
   3 //  LICENSE file in the root directory of this source tree. An additional grant
   4 //  of patent rights can be found in the PATENTS file in the same directory.
   5 //
   6 /*
   7   Murmurhash from http://sites.google.com/site/murmurhash/
   8
   9   All code is released to the public domain. For business purposes, Murmurhash is
  10   under the MIT license.
  11 */
  12 #pragma once
  13 #include <stdint.h>
  14 #include "rocksdb/slice.h"
  15
  16 #if defined(__x86_64__)
  17 #define MURMUR_HASH MurmurHash64A
  18 uint64_t MurmurHash64A ( const void * key, int len, unsigned int seed );
  19 #define MurmurHash MurmurHash64A
  20 typedef uint64_t murmur_t;
  21
  22 #elif defined(__i386__)
  23 #define MURMUR_HASH MurmurHash2
  24 unsigned int MurmurHash2 ( const void * key, int len, unsigned int seed );
  25 #define MurmurHash MurmurHash2
  26 typedef unsigned int murmur_t;
  27
  28 #else
  29 #define MURMUR_HASH MurmurHashNeutral2
  30 unsigned int MurmurHashNeutral2 ( const void * key, int len, unsigned int seed );
  31 #define MurmurHash MurmurHashNeutral2
  32 typedef unsigned int murmur_t;
  33 #endif
  34
  35 // Allow slice to be hashable by murmur hash.
  36 namespace rocksdb {
  37 struct murmur_hash {
  38   size_t operator()(const Slice& slice) const {
  39     return MurmurHash(slice.data(), static_cast<int>(slice.size()), 0);
  40   }
  41 };
  42 }  // rocksdb