Method Deserialize

cpp/src/parquet/bloom_filter.cc:288–353

}

BlockSplitBloomFilter BlockSplitBloomFilter::Deserialize(
    const ReaderProperties& properties, ArrowInputStream* input,
    std::optional<int64_t> bloom_filter_length) {
  ThriftDeserializer deserializer(properties);
  format::BloomFilterHeader header;
  int64_t bloom_filter_header_read_size = 0;
  if (bloom_filter_length.has_value()) {
    bloom_filter_header_read_size = bloom_filter_length.value();
  } else {
    // NOTE: we don't know the bloom filter header size upfront without
    // bloom_filter_length, and we can't rely on InputStream::Peek() which isn't always
    // implemented. Therefore, we must first Read() with an upper bound estimate of the
    // header size, then once we know the bloom filter data size, we can Read() the exact
    // number of remaining data bytes.
    bloom_filter_header_read_size = kBloomFilterHeaderSizeGuess;
  }

  // Read and deserialize bloom filter header
  PARQUET_ASSIGN_OR_THROW(auto header_buf, input->Read(bloom_filter_header_read_size));
  // This gets used, then set by DeserializeThriftMsg
  uint32_t header_size = static_cast<uint32_t>(header_buf->size());
  try {
    deserializer.DeserializeMessage(header_buf->data(), &header_size, &header);
    DCHECK_LE(header_size, header_buf->size());
  } catch (std::exception& e) {
    std::stringstream ss;
    ss << "Deserializing bloom filter header failed.\n" << e.what();
    throw ParquetException(ss.str());
  }
  PARQUET_THROW_NOT_OK(ValidateBloomFilterHeader(header));

  const int32_t bloom_filter_size = header.numBytes;
  if (bloom_filter_size + header_size <= header_buf->size()) {
    // The bloom filter data is entirely contained in the buffer we just read
    // => just return it.
    BlockSplitBloomFilter bloom_filter(properties.memory_pool());
    bloom_filter.Init(header_buf->data() + header_size, bloom_filter_size);
    return bloom_filter;
  }
  if (bloom_filter_length && *bloom_filter_length != bloom_filter_size + header_size) {
    // We know the bloom filter data size, but the real size is different.
    std::stringstream ss;
    ss << "Bloom filter length (" << bloom_filter_length.value()
       << ") does not match the actual bloom filter (size: "
       << bloom_filter_size + header_size << ").";
    throw ParquetException(ss.str());
  }
  // We have read a part of the bloom filter already, copy it to the target buffer
  // and read the remaining part from the InputStream.
  auto buffer = AllocateBuffer(properties.memory_pool(), bloom_filter_size);

  const auto bloom_filter_bytes_in_header = header_buf->size() - header_size;
  if (bloom_filter_bytes_in_header > 0) {
    std::memcpy(buffer->mutable_data(), header_buf->data() + header_size,
                static_cast<size_t>(bloom_filter_bytes_in_header));
  }

  const auto required_read_size = bloom_filter_size - bloom_filter_bytes_in_header;