Method ReadVariableArray

IO/EnSight/core/EnSightDataSet.cxx:1771–1868

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vtkSmartPointer<vtkFloatArray> EnSightDataSet::ReadVariableArray(
  EnSightFile& file, const std::string& sectionHeader, vtkIdType numElements, int numComponents)
{
  // handles reading float arrays for variables
  // handles partial and undefined values
  // undef gets converted to NaN because that is what VTK/ParaView uses
  std::regex regEx("^[^ ]+ ([^ ]+)");
  std::smatch sm;
  const bool match = std::regex_search(sectionHeader, sm, regEx);
  const bool hasUndef = (match && sm.str(1) == "undef");
  const bool hasPartial = (match && sm.str(1) == "partial");

  float undefValue = 0;
  if (hasUndef)
  {
    file.ReadNumber(&undefValue);
  }

  vtkNew<vtkIdList> partialIndices;
  if (hasPartial)
  {
    int count;
    file.ReadNumber(&count);

    std::vector<int> buffer(count);
    file.ReadArray(&buffer.front(), count);

    partialIndices->SetNumberOfIds(count);
    std::transform(buffer.begin(), buffer.end(), partialIndices->WritePointer(0, count),
      [](vtkIdType val)
      {
        return val - 1; /* since ensight indices start with 1*/
      });
  }

  // replace undefined values with "internal undef" which in ParaView is NaN
  auto replaceUndef = [&](vtkFloatArray* farray)
  {
    if (hasUndef)
    {
      for (vtkIdType cc = 0; cc < numElements; ++cc)
      {
        if (farray->GetTypedComponent(cc, 0) == undefValue)
        {
          farray->SetTypedComponent(cc, 0, std::nanf("1"));
        }
      }
    }
  };

  auto readComponent = [&](vtkIdType count)
  {
    vtkNew<vtkFloatArray> buffer;
    buffer->SetNumberOfTuples(count);
    if (hasPartial)
    {
      // fill with NaNs
      buffer->FillValue(std::nanf("1"));