src/parquet/compression.h

// 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.

#ifndef PARQUET_COMPRESSION_CODEC_H
#define PARQUET_COMPRESSION_CODEC_H

#include <zlib.h>

#include <cstdint>
#include <memory>

#include "parquet/exception.h"
#include "parquet/types.h"

namespace parquet {

class Codec {
 public:
  virtual ~Codec() {}

  static std::unique_ptr<Codec> Create(Compression::type codec);

  virtual void Decompress(int64_t input_len, const uint8_t* input, int64_t output_len,
      uint8_t* output_buffer) = 0;

  virtual int64_t Compress(int64_t input_len, const uint8_t* input,
      int64_t output_buffer_len, uint8_t* output_buffer) = 0;

  virtual int64_t MaxCompressedLen(int64_t input_len, const uint8_t* input) = 0;

  virtual const char* name() const = 0;
};

// Snappy codec.
class SnappyCodec : public Codec {
 public:
  virtual void Decompress(int64_t input_len, const uint8_t* input, int64_t output_len,
      uint8_t* output_buffer);

  virtual int64_t Compress(int64_t input_len, const uint8_t* input,
      int64_t output_buffer_len, uint8_t* output_buffer);

  virtual int64_t MaxCompressedLen(int64_t input_len, const uint8_t* input);

  virtual const char* name() const { return "snappy"; }
};

// Brotli codec.
class BrotliCodec : public Codec {
 public:
  void Decompress(int64_t input_len, const uint8_t* input, int64_t output_len,
      uint8_t* output_buffer) override;

  int64_t Compress(int64_t input_len, const uint8_t* input, int64_t output_buffer_len,
      uint8_t* output_buffer) override;

  int64_t MaxCompressedLen(int64_t input_len, const uint8_t* input) override;

  const char* name() const override { return "brotli"; }
};

// GZip codec.
class GZipCodec : public Codec {
 public:
  /// Compression formats supported by the zlib library
  enum Format {
    ZLIB,
    DEFLATE,
    GZIP,
  };

  explicit GZipCodec(Format format = GZIP);
  virtual ~GZipCodec();

  virtual void Decompress(int64_t input_len, const uint8_t* input, int64_t output_len,
      uint8_t* output_buffer);

  virtual int64_t Compress(int64_t input_len, const uint8_t* input,
      int64_t output_buffer_len, uint8_t* output_buffer);

  virtual int64_t MaxCompressedLen(int64_t input_len, const uint8_t* input);

  virtual const char* name() const { return "gzip"; }

 private:
  // zlib is stateful and the z_stream state variable must be initialized
  // before
  z_stream stream_;

  // Realistically, this will always be GZIP, but we leave the option open to
  // configure
  Format format_;

  // These variables are mutually exclusive. When the codec is in "compressor"
  // state, compressor_initialized_ is true while decompressor_initialized_ is
  // false. When it's decompressing, the opposite is true.
  //
  // Indeed, this is slightly hacky, but the alternative is having separate
  // Compressor and Decompressor classes. If this ever becomes an issue, we can
  // perform the refactoring then
  void InitCompressor();
  void InitDecompressor();
  void EndCompressor();
  void EndDecompressor();
  bool compressor_initialized_;
  bool decompressor_initialized_;
};

}  // namespace parquet

#endif