Decompressor.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * Licensed 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.
 */
 
#pragma once
 
#include <memory>
#include <vector>
 
#include <vrs/ForwardDefinitions.h>
 
namespace vrs {
 
class Decompressor {
 public:
  Decompressor();
  ~Decompressor();
 
  void setCompressionType(CompressionType compressionType);
  CompressionType getCompressionType() const {
    return compressionType_;
  }
 
  size_t getRecommendedInputBufferSize() const;
 
  int decompress(void* destination, uint32_t destinationSize, uint32_t& outReadSize);
 
  void* allocateCompressedDataBuffer(size_t requestSize);
 
  size_t getRemainingCompressedDataBufferSize() const {
    return readSize_ - decodedSize_;
  }
 
  int initFrame(FileHandler& file, size_t& outFrameSize, size_t& inOutMaxReadSize);
  int readFrame(FileHandler& file, void* dst, size_t frameSize, size_t& inOutMaxReadSize);
 
  void reset();
 
 private:
  const void* getCompressedData() const {
    return compressedBuffer_.data() + decodedSize_;
  }
  size_t getCompressedDataSize() const {
    return readSize_ - decodedSize_;
  }
 
  class Lz4Decompressor;
  std::unique_ptr<Lz4Decompressor> lz4Context_;
  class ZstdDecompressor;
  std::unique_ptr<ZstdDecompressor> zstdContext_;
  std::vector<uint8_t> compressedBuffer_;
  CompressionType compressionType_{};
  size_t readSize_ = {};
  size_t decodedSize_ = {};
  size_t lastResult_ = {};
};
 
} // namespace vrs