Method WriteSignalData

lib/mdflib/mdflib/src/cn4block.cpp:1187–1256

}

uint64_t Cn4Block::WriteSignalData(std::streambuf& buffer, bool compress) {
  uint64_t bytes = 0;

  if (Type() == ChannelType::MaxLength ||
      (Type() == ChannelType::VariableLength && VlsdRecordId() > 0) ) {
    // Signal data is updated elsewhere
    return 0;
  }

  if (data_list_.empty()) {
    UpdateLink(buffer, kIndexData, 0); // No data link
  } else if (!compress || data_list_.size() <= 100 ){
    // Store as SD block
    auto sd4 = std::make_unique<Sd4Block>();
    sd4->Data(data_list_);
    bytes = sd4->Write(buffer);
    UpdateLink(buffer, kIndexData,sd4->FilePosition());
  } else if (data_list_.size() <= kMaxDataSize) { // Compress data
    // Store DZ (SD) block
    auto dz4 = std::make_unique<Dz4Block>();
    dz4->OrigBlockType("SD");
    dz4->Type(Dz4ZipType::Deflate);
    dz4->Data(data_list_); // Compress and set up the sizes
    bytes = dz4->Write(buffer);
    UpdateLink(buffer, kIndexData,dz4->FilePosition());
  } else {
    // Store HL + DL + DZ blocks
    auto hl4 = std::make_unique<Hl4Block>();
    hl4->Flags(Hl4Flags::EqualLength);
    hl4->Type(Hl4ZipType::Deflate);

    auto dl4 = std::make_unique<Dl4Block>();
    std::vector<uint8_t> data;
    data.reserve(kMaxDataSize);
    dl4->Flags(Dl4Flags::EqualLength);
    dl4->EqualLength(kMaxDataSize);

    for (const auto in_byte : data_list_) {
      data.push_back(in_byte);
      if (data.size() + 1 > kMaxDataSize) {
        auto dz4 = std::make_unique<Dz4Block>();
        dz4->OrigBlockType("SD");
        dz4->Type(Dz4ZipType::Deflate);
        dz4->Data(data); // Compress and set up the sizes

        auto& block_list = dl4->DataBlockList();
        block_list.push_back(std::move(dz4));

        data.clear();
        data.shrink_to_fit();
        data.reserve(kMaxDataSize);
      }
    }
    if (!data.empty()) {
      auto dz4 = std::make_unique<Dz4Block>();
      dz4->OrigBlockType("SD");
      dz4->Type(Dz4ZipType::Deflate);
      dz4->Data(data); // Compress and set up the sizes