/*=========================================================================

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkProcessObject.h,v $
  Language:  C++
  Date:      $Date: 2001/10/11 13:36:22 $
  Version:   $Revision: 1.29 $


Copyright (c) 1993-2001 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

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 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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=========================================================================*/
// .NAME vtkProcessObject - abstract class specifies interface for visualization filters
//
// .SECTION Description
// vtkProcessObject is an abstract object that specifies behavior and
// interface of visualization network process objects (sources, filters,
// mappers). Source objects are creators of visualization data; filters
// input, process, and output visualization data; and mappers transform data
// into another form (like rendering primitives or write data to a file).
//
// vtkProcessObject provides a mechanism for invoking the methods
// StartMethod() and EndMethod() before and after object execution (via
// Execute()). These are convenience methods you can use for any purpose
// (e.g., debugging info, highlighting/notifying user interface, etc.) These
// methods accept a single void* pointer that can be used to send data to the
// methods. It is also possible to specify a function to delete the argument
// via StartMethodArgDelete and EndMethodArgDelete.
//
// Another method, ProgressMethod() can be specified. Some filters invoke this 
// method periodically during their execution. The use is similar to that of 
// StartMethod() and EndMethod(). Filters may also check their AbortExecute
// flag to determine whether to prematurely end their execution.
//
// An important feature of subclasses of vtkProcessObject is that it is
// possible to control the memory-management model (i.e., retain output
// versus delete output data). If enabled the ReleaseDataFlag enables the
// deletion of the output data once the downstream process object finishes
// processing the data (please see text).  
//
// .SECTION See Also
// vtkDataObject vtkSource vtkFilter vtkMapper vtkWriter

#ifndef __vtkProcessObject_h
#define __vtkProcessObject_h

#include "vtkDataObject.h"

class VTK_COMMON_EXPORT vtkProcessObject : public vtkObject
{
public:
  // Description:
  // Instantiate object with no start, end, or progress methods.
  static vtkProcessObject *New();

  vtkTypeMacro(vtkProcessObject,vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Specify function to be called before object executes.
  void SetStartMethod(void (*f)(void *), void *arg);

  // Description:
  // Specify function to be called to show progress of filter
  void SetProgressMethod(void (*f)(void *), void *arg);

  // Description:
  // Specify function to be called after object executes.
  void SetEndMethod(void (*f)(void *), void *arg);

  // Description:
  // Set the arg delete method. This is used to free user memory.
  void SetStartMethodArgDelete(void (*f)(void *));

  // Description:
  // Set the arg delete method. This is used to free user memory.
  void SetProgressMethodArgDelete(void (*f)(void *));

  // Description:
  // Set the arg delete method. This is used to free user memory.
  void SetEndMethodArgDelete(void (*f)(void *));

  // Description:
  // Set/Get the AbortExecute flag for the process object. Process objects
  // may handle premature termination of execution in different ways.
  vtkSetMacro(AbortExecute,int);
  vtkGetMacro(AbortExecute,int);
  vtkBooleanMacro(AbortExecute,int);

  // Description:
  // Set/Get the execution progress of a process object.
  vtkSetClampMacro(Progress,float,0.0,1.0);
  vtkGetMacro(Progress,float);

  // Description:
  // Update the progress of the process object. If a ProgressMethod exists,
  // executes it.  Then set the Progress ivar to amount. The parameter amount
  // should range between (0,1).
  void UpdateProgress(float amount);

  // Description:
  // Set the current text message associated with the progress state.
  // This may be used by a calling process/GUI.
  vtkSetStringMacro(ProgressText);
  vtkGetStringMacro(ProgressText);

  // left public for performance since it is used in inner loops
  int AbortExecute;

  // Description:
  // Return an array with all the inputs of this process object.
  // This is useful for tracing back in the pipeline to construct
  // graphs etc.
  vtkDataObject **GetInputs() {return this->Inputs;}
  vtkGetMacro(NumberOfInputs,int);

  // Description:
  // This method will rearrange the input array so that all NULL entries 
  // are removed.
  void SqueezeInputArray();
  
  // Description:
  // Remove all the input data.
  void RemoveAllInputs();

protected:
  vtkProcessObject();
  ~vtkProcessObject();

  // Progress/Update handling
  unsigned long StartTag;
  unsigned long ProgressTag;
  unsigned long EndTag;
  float Progress;
  char  *ProgressText;

  int NumberOfInputs;
  int NumberOfRequiredInputs;
  vtkDataObject **Inputs;     //An array of the inputs to the filter
  // Temporary arrays used internally.  
  // It is only valid after SortInputsByLocality is called.
  vtkDataObject **SortedInputs;   // Inputs sorted by locality
  // We need a second array for an effficeint search.  
  // This array is never valid.
  vtkDataObject **SortedInputs2;   
  void SortInputsByLocality();
  // A helper method for quicksort.
  void SortMerge(vtkDataObject **a1, int l1,
                 vtkDataObject **a2, int l2,
                 vtkDataObject **results);

  // Called to allocate the input array.  Copies old inputs.
  void SetNumberOfInputs(int num);

  // protected methods for setting inputs.
  virtual void SetNthInput(int num, vtkDataObject *input);
  virtual void AddInput(vtkDataObject *input);
  virtual void RemoveInput(vtkDataObject *input);
  
private:
  vtkProcessObject(const vtkProcessObject&);  // Not implemented.
  void operator=(const vtkProcessObject&);  // Not implemented.
};

#endif

