Deal with 0 dimensions

IO/NetCDF/vtkNetCDFReader.cxx

@@ -299,7 +299,11 @@ int vtkNetCDFReader::RequestInformation(vtkInformation* vtkNotUsed(request),
   for (int i = 0; i < 3; i++)
   {
     this->WholeExtent[2 * i] = 0;
-    if (i < this->LoadingDimensions->GetNumberOfTuples())
+    vtkIdType ndims = this->LoadingDimensions->GetNumberOfTuples();
+    // if there are 0 dimensions
+    // generate an empty image with (0, -1, 0 -1, 0, -1)
+    int maxExtent = ndims > 0 ? 0 : -1;
+    if (i < ndims)
     {
       size_t dimlength;
       // Remember that netCDF arrays are indexed backward from VTK images.
@@ -312,7 +316,7 @@ int vtkNetCDFReader::RequestInformation(vtkInformation* vtkNotUsed(request),
     }
     else
     {
-      this->WholeExtent[2 * i + 1] = 0;
+      this->WholeExtent[2 * i + 1] = maxExtent;
     }
   }
   vtkDebugMacro(<< "Whole extents: " << this->WholeExtent[0] << ", " << this->WholeExtent[1] << ", "

IO/NetCDF/vtkXArrayAccessor.cxx

@@ -323,9 +323,9 @@ void vtkXArrayAccessor::PrintVarValue(
 bool vtkXArrayAccessor::IsContiguous(int varid, const size_t* startp, const size_t* countp)
 {
   // the last dim is the most rapidly varying
-  size_t ndims = this->VarDims[varid].size();
-  size_t contiguousDims = 0;
-  for (int i = static_cast<int>(ndims - 1); i >= 0; --i)
+  int ndims = static_cast<int>(this->VarDims[varid].size());
+  int contiguousDims = 0;
+  for (int i = ndims - 1; i >= 0; --i)
   {
     if (startp[i] == 0 && countp[i] == this->DimLen[this->VarDims[varid][i]])
     {
@@ -343,11 +343,14 @@ std::vector<size_t> vtkXArrayAccessor::GetDimIncrement(int varid)
 {
   size_t ndims = this->VarDims[varid].size();
   std::vector<size_t> dimIncrement;
-  dimIncrement.resize(ndims);
-  dimIncrement[ndims - 1] = 1;
-  for (size_t i = ndims - 1; i >= 1; --i)
+  if (ndims > 0)
   {
-    dimIncrement[i - 1] = dimIncrement[i] * this->DimLen[this->VarDims[varid][i]];
+    dimIncrement.resize(ndims);
+    dimIncrement[ndims - 1] = 1;
+    for (size_t i = ndims - 1; i >= 1; --i)
+    {
+      dimIncrement[i - 1] = dimIncrement[i] * this->DimLen[this->VarDims[varid][i]];
+    }
   }
   return dimIncrement;
 }