Files
scylladb/utils/murmur_hash.hh
Avi Kivity 678c259c66 murmur3: switch to unsigned types
C++ doesn't define overflow on signed types, so use unsigned types instead.
Luckily all right shifts were unsigned anyway.

Some signed extension was happening (handling remainders after processing
8-byte chunks) but should still be there.

Caught by debug build.
2015-02-24 15:29:08 +02:00

51 lines
1.7 KiB
C++

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Modified by Cloudius Systems.
* Copyright 2015 Cloudius Systems.
*/
#pragma once
#include <cstdint>
#include <array>
#include "database.hh"
/**
* This is a very fast, non-cryptographic hash suitable for general hash-based
* lookup. See http://murmurhash.googlepages.com/ (Murmur Hash 2) and
* https://code.google.com/p/smhasher/wiki/MurmurHash3.
*
* This code is not based on the original Murmur Hash C code, but rather
* a translation of Cassandra's Java version back to C.
**/
namespace utils {
namespace murmur_hash
{
uint32_t hash32(const bytes &data, uint32_t offset, uint32_t length,
int32_t seed);
uint64_t hash2_64(const bytes &key, uint32_t offset, uint32_t length,
uint64_t seed);
void hash3_x64_128(const bytes &key, uint32_t offset, uint32_t length,
uint64_t seed, std::array<uint64_t,2> &result);
};
} // namespace utils