Function ScanForProcessorDirs

IO/Parallel/vtkPOpenFOAMReader.cxx:169–346

Search and list processor subdirectories Detect collated and uncollated processor directories - "processor(\d+)" - "processors(\d+)" - "processors(\d+)_(\d+)-(\d+)" string parsing logic as per fileOperation / parseProcsNumRange from OpenFOAM-v2012 Return either collated or uncollated directories, never a mix. Use the number of components to distinguish

// Return either collated or uncollated directories, never a mix.
// Use the number of components to distinguish
vtkSmartPointer<vtkIntArray> ScanForProcessorDirs(vtkDirectory* dir)
{
  // Uncollated: save processor id
  auto uncollated = vtkSmartPointer<vtkIntArray>::New();
  uncollated->SetNumberOfComponents(1);

  // Collated: save (processor count, first, size) tuple
  auto collated = vtkSmartPointer<vtkIntArray>::New();
  collated->SetNumberOfComponents(3);

  // Sort keys for collated
  vtkNew<vtkIntArray> collatedNums;
  int procTuple[3] = { 0, 0, 0 };

  const vtkIdType nFiles = dir->GetNumberOfFiles();
  for (vtkIdType filei = 0; filei < nFiles; ++filei)
  {
    const char* subdir = dir->GetFile(filei);

    if (strncmp(subdir, "processor", 9) != 0 || !dir->FileIsDirectory(subdir))
    {
      continue;
    }

    if (isdigit(subdir[9]))
    {
      // processor<digits>
      const char* nptr = (subdir + 9);

      errno = 0;
      long parsed;
      auto result = vtk::from_chars(nptr, parsed);
      if (errno || nptr == result.ptr)
      {
        continue; // bad parse
      }
      const auto procId = static_cast<int>(parsed);

      // Require end of string
      if (*(result.ptr) == '\0')
      {
        uncollated->InsertNextValue(procId);
      }
    }
    else if (subdir[9] == 's' && isdigit(subdir[10]))
    {
      // processors<digits> or processors<digits>_<digits>-<digits>
      const char* nptr = (subdir + 10);

      // 1. numProcs
      errno = 0;
      long parsed;
      auto result = vtk::from_chars(nptr, parsed);
      if (errno || nptr == result.ptr)
      {
        continue; // bad parse
      }
      const auto nProcs = static_cast<int>(parsed);