mirror of https://github.com/facebook/rocksdb.git
53 lines
1.7 KiB
C++
53 lines
1.7 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
|
|
// This source code is licensed under both the GPLv2 (found in the
|
|
// COPYING file in the root directory) and Apache 2.0 License
|
|
// (found in the LICENSE.Apache file in the root directory).
|
|
//
|
|
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file. See the AUTHORS file for names of contributors.
|
|
//
|
|
// Simple hash function used for internal data structures
|
|
|
|
#pragma once
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
|
|
#include "rocksdb/slice.h"
|
|
#include "util/murmurhash.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
// Non-persistent hash. Only used for in-memory data structure
|
|
// The hash results are applicable to change.
|
|
extern uint64_t NPHash64(const char* data, size_t n, uint32_t seed);
|
|
|
|
extern uint32_t Hash(const char* data, size_t n, uint32_t seed);
|
|
|
|
inline uint32_t BloomHash(const Slice& key) {
|
|
return Hash(key.data(), key.size(), 0xbc9f1d34);
|
|
}
|
|
|
|
inline uint64_t GetSliceNPHash64(const Slice& s) {
|
|
return NPHash64(s.data(), s.size(), 0);
|
|
}
|
|
|
|
inline uint32_t GetSliceHash(const Slice& s) {
|
|
return Hash(s.data(), s.size(), 397);
|
|
}
|
|
|
|
inline uint64_t NPHash64(const char* data, size_t n, uint32_t seed) {
|
|
// Right now murmurhash2B is used. It should able to be freely
|
|
// changed to a better hash, without worrying about backward
|
|
// compatibility issue.
|
|
return MURMUR_HASH(data, static_cast<int>(n),
|
|
static_cast<unsigned int>(seed));
|
|
}
|
|
|
|
// std::hash compatible interface.
|
|
struct SliceHasher {
|
|
uint32_t operator()(const Slice& s) const { return GetSliceHash(s); }
|
|
};
|
|
|
|
} // namespace rocksdb
|