text: /*=========================================================================
  
    Program:   Visualization Toolkit
    Module:    vtkUnstructuredGridBaseAlgorithm.cxx
  
    Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
    All rights reserved.
    See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
  
       This software is distributed WITHOUT ANY WARRANTY; without even
       the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
       PURPOSE.  See the above copyright notice for more information.
  
  =========================================================================*/
  #include "vtkUnstructuredGridBaseAlgorithm.h"
  
  #include "vtkObjectFactory.h"
  #include "vtkInformation.h"
  #include "vtkInformationVector.h"
  #include "vtkUnstructuredGridBase.h"
  #include "vtkStreamingDemandDrivenPipeline.h"
  
  vtkStandardNewMacro(vtkUnstructuredGridBaseAlgorithm)
  
  //----------------------------------------------------------------------------
  vtkUnstructuredGridBaseAlgorithm::vtkUnstructuredGridBaseAlgorithm()
  {
    // by default assume filters have one input and one output
    // subclasses that deviate should modify this setting
    this->SetNumberOfInputPorts(1);
    this->SetNumberOfOutputPorts(1);
  }
  
  //----------------------------------------------------------------------------
  vtkUnstructuredGridBaseAlgorithm::~vtkUnstructuredGridBaseAlgorithm() = default;
  
  //----------------------------------------------------------------------------
  void vtkUnstructuredGridBaseAlgorithm::PrintSelf(ostream& os, vtkIndent indent)
  {
    this->Superclass::PrintSelf(os, indent);
  }
  
  //----------------------------------------------------------------------------
  vtkUnstructuredGridBase *vtkUnstructuredGridBaseAlgorithm::GetOutput()
  {
    return this->GetOutput(0);
  }
  
  //----------------------------------------------------------------------------
  vtkUnstructuredGridBase *vtkUnstructuredGridBaseAlgorithm::GetOutput(int port)
  {
    return vtkUnstructuredGridBase::SafeDownCast(this->GetOutputDataObject(port));
  }
  
  //----------------------------------------------------------------------------
  void vtkUnstructuredGridBaseAlgorithm::SetOutput(vtkDataObject* d)
  {
    this->GetExecutive()->SetOutputData(0, d);
  }
  
  //----------------------------------------------------------------------------
  vtkTypeBool vtkUnstructuredGridBaseAlgorithm::ProcessRequest(vtkInformation* request,
                                           vtkInformationVector** inputVector,
                                           vtkInformationVector* outputVector)
  {
    // generate the data
    if(request->Has(vtkDemandDrivenPipeline::REQUEST_DATA()))
    {
      return this->RequestData(request, inputVector, outputVector);
    }
  
    // create the output
    if(request->Has(vtkDemandDrivenPipeline::REQUEST_DATA_OBJECT()))
    {
      return this->RequestDataObject(request, inputVector, outputVector);
    }
  
    // set update extent
    if(request->Has(vtkStreamingDemandDrivenPipeline::REQUEST_UPDATE_EXTENT()))
    {
      return this->RequestUpdateExtent(request, inputVector, outputVector);
    }
  
    // execute information
    if(request->Has(vtkDemandDrivenPipeline::REQUEST_INFORMATION()))
    {
      return this->RequestInformation(request, inputVector, outputVector);
    }
  
    return this->Superclass::ProcessRequest(request, inputVector, outputVector);
  }
  
  //----------------------------------------------------------------------------
  int vtkUnstructuredGridBaseAlgorithm::FillOutputPortInformation(
    int vtkNotUsed(port), vtkInformation* info)
  {
    // now add our info
    info->Set(vtkDataObject::DATA_TYPE_NAME(), "vtkUnstructuredGridBase");
    return 1;
  }
  
  //----------------------------------------------------------------------------
  int vtkUnstructuredGridBaseAlgorithm::FillInputPortInformation(
    int vtkNotUsed(port), vtkInformation* info)
  {
    info->Set(vtkAlgorithm::INPUT_REQUIRED_DATA_TYPE(),
              "vtkUnstructuredGridBase");
    return 1;
  }
  
  //----------------------------------------------------------------------------
  int vtkUnstructuredGridBaseAlgorithm::RequestInformation(
    vtkInformation* vtkNotUsed(request),
    vtkInformationVector** vtkNotUsed(inputVector),
    vtkInformationVector* vtkNotUsed(outputVector))
  {
    // do nothing let subclasses handle it
    return 1;
  }
  
  //----------------------------------------------------------------------------
  int vtkUnstructuredGridBaseAlgorithm::RequestUpdateExtent(
    vtkInformation* vtkNotUsed(request),
    vtkInformationVector** inputVector,
    vtkInformationVector* vtkNotUsed(outputVector))
  {
    int numInputPorts = this->GetNumberOfInputPorts();
    for (int i=0; i<numInputPorts; i++)
    {
      int numInputConnections = this->GetNumberOfInputConnections(i);
      for (int j=0; j<numInputConnections; j++)
      {
        vtkInformation* inputInfo = inputVector[i]->GetInformationObject(j);
        inputInfo->Set(vtkStreamingDemandDrivenPipeline::EXACT_EXTENT(), 1);
      }
    }
    return 1;
  }
  
  //----------------------------------------------------------------------------
  // This is the superclasses style of Execute method.  Convert it into
  // an imaging style Execute method.
  int vtkUnstructuredGridBaseAlgorithm::RequestData(
    vtkInformation* vtkNotUsed( request ),
    vtkInformationVector** vtkNotUsed( inputVector ),
    vtkInformationVector* vtkNotUsed( outputVector ))
  {
    return 0;
  }
  
  //----------------------------------------------------------------------------
  int vtkUnstructuredGridBaseAlgorithm::RequestDataObject(
      vtkInformation *, vtkInformationVector **inputVector,
      vtkInformationVector *outputVector)
  {
    vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
    if (!inInfo)
    {
      return 0;
    }
    vtkUnstructuredGridBase *input = vtkUnstructuredGridBase::SafeDownCast(
          inInfo->Get(vtkDataObject::DATA_OBJECT()));
  
    if (input)
    {
      // for each output
      for(int i=0; i < this->GetNumberOfOutputPorts(); ++i)
      {
        vtkInformation* info = outputVector->GetInformationObject(i);
        vtkUnstructuredGridBase *output = vtkUnstructuredGridBase::SafeDownCast(
              info->Get(vtkDataObject::DATA_OBJECT()));
  
        if (!output || !output->IsA(input->GetClassName()))
        {
          vtkUnstructuredGridBase* newOutput = input->NewInstance();
          info->Set(vtkDataObject::DATA_OBJECT(), newOutput);
          newOutput->Delete();
        }
      }
      return 1;
    }
    return 0;
  }
  
  //----------------------------------------------------------------------------
  void vtkUnstructuredGridBaseAlgorithm::SetInputData(vtkDataObject* input)
  {
    this->SetInputData(0, input);
  }
  
  //----------------------------------------------------------------------------
  void vtkUnstructuredGridBaseAlgorithm::SetInputData(int index,
                                                      vtkDataObject* input)
  {
    this->SetInputDataInternal(index, input);
  }
  
  //----------------------------------------------------------------------------
  void vtkUnstructuredGridBaseAlgorithm::AddInputData(vtkDataObject* input)
  {
    this->AddInputData(0, input);
  }
  
  //----------------------------------------------------------------------------
  void vtkUnstructuredGridBaseAlgorithm::AddInputData(int index,
                                                      vtkDataObject* input)
  {
    this->AddInputDataInternal(index, input);
  }
  