ceph/src/arrow/cpp/src/parquet/murmur3.h

   1 // Licensed to the Apache Software Foundation (ASF) under one
   2 // or more contributor license agreements.  See the NOTICE file
   3 // distributed with this work for additional information
   4 // regarding copyright ownership.  The ASF licenses this file
   5 // to you under the Apache License, Version 2.0 (the
   6 // "License"); you may not use this file except in compliance
   7 // with the License.  You may obtain a copy of the License at
   8 //
   9 //   http://www.apache.org/licenses/LICENSE-2.0
  10 //
  11 // Unless required by applicable law or agreed to in writing,
  12 // software distributed under the License is distributed on an
  13 // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14 // KIND, either express or implied.  See the License for the
  15 // specific language governing permissions and limitations
  16 // under the License.
  17
  18 //-----------------------------------------------------------------------------
  19 // MurmurHash3 was written by Austin Appleby, and is placed in the public
  20 // domain. The author hereby disclaims copyright to this source code.
  21
  22 #pragma once
  23
  24 #include <cstdint>
  25
  26 #include "parquet/hasher.h"
  27 #include "parquet/platform.h"
  28 #include "parquet/types.h"
  29
  30 namespace parquet {
  31
  32 /// Source:
  33 /// https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp
  34 /// (Modified to adapt to coding conventions and to inherit the Hasher abstract class)
  35 class PARQUET_EXPORT MurmurHash3 : public Hasher {
  36  public:
  37   MurmurHash3() : seed_(DEFAULT_SEED) {}
  38   uint64_t Hash(int32_t value) const override;
  39   uint64_t Hash(int64_t value) const override;
  40   uint64_t Hash(float value) const override;
  41   uint64_t Hash(double value) const override;
  42   uint64_t Hash(const Int96* value) const override;
  43   uint64_t Hash(const ByteArray* value) const override;
  44   uint64_t Hash(const FLBA* val, uint32_t len) const override;
  45
  46  private:
  47   // Default seed for hash which comes from Bloom filter in parquet-mr, it is generated
  48   // by System.nanoTime() of java.
  49   static constexpr int DEFAULT_SEED = 1361930890;
  50
  51   uint32_t seed_;
  52 };
  53
  54 }  // namespace parquet