Method ReadCellArray

IO/XML/vtkXMLUnstructuredDataReader.cxx:632–908

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//------------------------------------------------------------------------------
int vtkXMLUnstructuredDataReader::ReadCellArray(vtkIdType numberOfCells,
  vtkIdType vtkNotUsed(totalNumberOfCells), vtkXMLDataElement* eCells, vtkCellArray* outCells)
{
  // This part is here to determine if we need to read the cell array.
  // If the cell array was already generated in a previous time step, there's no need recreating it.
  // However, within a same time step, multiple pieces can be present. We need to read them all.
  // The logic works as follows:
  // * If there's no output geometry yet, it means we need to create it. We save the current time
  //   step to know in which time step the cell array is being read.
  // * If there's already geometry, we either are in a new time step and nothing needs to be done,
  //   or we're still in the time step used to create the geometry in a new piece and we need to
  //   read it.
  // We quit the "create geometry mode" if the cell array time step becomes different than the
  // current time step.
  if ((this->ReadFromInputString &&
        this->CellArrayCachedInputString != this->InputString.c_str()) ||
    (!this->ReadFromInputString && this->CellArrayCachedFileName != this->FileName))
  {
    // We wipe the geometry if a new file or new input string is to be read.
    outCells->Initialize();
    if (this->ReadFromInputString)
    {
      this->CellArrayCachedInputString = this->InputString.c_str();
    }
    else
    {
      this->CellArrayCachedFileName = this->FileName;
    }
  }
  if (outCells->GetNumberOfCells() == 0)
  {
    this->CellArrayTimeStepRead = this->CurrentTimeStep;
    this->CanReadCellArray = true;
  }
  if (this->CellArrayTimeStepRead != this->CurrentTimeStep)
  {
    this->CanReadCellArray = false;
  }
  if (!this->CanReadCellArray || numberOfCells <= 0)
  {
    return 1;
  }
  else
  {
    if (!eCells)
    {
      return 0;
    }
  }

  // Split progress range into 1/5 for offsets array and 4/5 for
  // connectivity array.  This assumes an average of 4 points per
  // cell.  Unfortunately, we cannot know the length of the
  // connectivity array ahead of time to calculate the real fraction.
  float progressRange[2] = { 0, 0 };
  this->GetProgressRange(progressRange);
  float fractions[3] = { 0, 0.2f, 1 };