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

  Program:   Visualization Toolkit
  Module:    vtkMemoryLimitImageDataStreamer.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 "vtkMemoryLimitImageDataStreamer.h"

#include "vtkAlgorithmOutput.h"
#include "vtkCommand.h"
#include "vtkExtentTranslator.h"
#include "vtkImageData.h"
#include "vtkInformation.h"
#include "vtkInformationVector.h"
#include "vtkObjectFactory.h"
#include "vtkPipelineSize.h"
#include "vtkStreamingDemandDrivenPipeline.h"

vtkStandardNewMacro(vtkMemoryLimitImageDataStreamer);

//----------------------------------------------------------------------------
vtkMemoryLimitImageDataStreamer::vtkMemoryLimitImageDataStreamer()
{
  // Set a default memory limit of 50 Megabytes
  this->MemoryLimit = 50000; 
}


//----------------------------------------------------------------------------
void vtkMemoryLimitImageDataStreamer::PrintSelf(ostream& os, vtkIndent indent)
{
  this->Superclass::PrintSelf(os,indent);

  os << indent << "MemoryLimit (in kb): " << this->MemoryLimit << endl;
}

//----------------------------------------------------------------------------
int
vtkMemoryLimitImageDataStreamer
::ProcessRequest(vtkInformation* request,
                 vtkInformationVector** inputVector,
                 vtkInformationVector* outputVector)
{
  if(request->Has(vtkStreamingDemandDrivenPipeline::REQUEST_UPDATE_EXTENT()))
    {
    if (this->CurrentDivision == 0)
      {
      // we must set the extent on the input
      vtkInformation* outInfo = outputVector->GetInformationObject(0);
      
      // get the requested update extent
      int outExt[6];
      outInfo->Get(vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(), outExt);
      
      vtkInformation* inInfo = inputVector[0]->GetInformationObject(0);
      vtkImageData *input = 
        vtkImageData::SafeDownCast(inInfo->Get(vtkDataObject::DATA_OBJECT()));
      
      vtkExtentTranslator *translator = this->GetExtentTranslator();
      translator->SetWholeExtent(outExt);
      
      vtkPipelineSize *sizer = vtkPipelineSize::New();
      this->NumberOfStreamDivisions = 1;
      unsigned long oldSize, size = 0;
      float ratio;
      translator->SetPiece(0);
      
      // watch for the limiting case where the size is the maximum size
      // represented by an unsigned long. In that case we do not want to do
      // the ratio test. We actual test for size < 0.5 of the max unsigned
      // long which would indicate that oldSize is about at max unsigned
      // long.
      unsigned long maxSize;
      maxSize = (((unsigned long)0x1) << (8*sizeof(unsigned long) - 1));
      
      // we also have to watch how many pieces we are creating. Since
      // NumberOfStreamDivisions is an int, it cannot be more that say 2^31
      // (which is a bit much anyhow) so we also stop if the number of pieces
      // is too large.
      int count = 0;

      
      // double the number of pieces until the size fits in memory
      // or the reduction in size falls to 20%
      do 
        {
        oldSize = size;
        translator->SetNumberOfPieces(this->NumberOfStreamDivisions);
        translator->PieceToExtentByPoints();

        int inExt[6];
        translator->GetExtent(inExt);
        // set the update extent
        inInfo->Set(
          vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT(), inExt, 6);
        // set a hint not to combine with previous requests
        inInfo->Set(
          vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT_INITIALIZED(),
          VTK_UPDATE_EXTENT_REPLACE);
        
        // then propagate it
        vtkAlgorithm *alg = input->GetProducerPort()->GetProducer();
        int index = input->GetProducerPort()->GetIndex();
        vtkStreamingDemandDrivenPipeline *exec = 
          vtkStreamingDemandDrivenPipeline::SafeDownCast(alg->GetExecutive());
        exec->PropagateUpdateExtent(index);

        // then reset the INITIALIZED flag to the default value COMBINE
        inInfo->Set(
          vtkStreamingDemandDrivenPipeline::UPDATE_EXTENT_INITIALIZED(),
          VTK_UPDATE_EXTENT_COMBINE);

        size = sizer->GetEstimatedSize(this,0,0);
        // watch for the first time through
        if (!oldSize)
          {
          ratio = 0.5;
          }
        // otherwise the normal ratio calculation
        else
          {
          ratio = size/(float)oldSize;
          }
        this->NumberOfStreamDivisions = this->NumberOfStreamDivisions*2;
        count++;
        }
      while (size > this->MemoryLimit && 
             (size < maxSize && ratio < 0.8) && count < 29);
      
      // undo the last *2
      this->NumberOfStreamDivisions = this->NumberOfStreamDivisions/2;
      sizer->Delete();
      }    
    return
      this->Superclass::ProcessRequest(request, inputVector, outputVector);
    }
  return this->Superclass::ProcessRequest(request, inputVector, outputVector);
}