/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#ifndef __itkRealToHalfHermitianForwardFFTImageFilter_hxx
#define __itkRealToHalfHermitianForwardFFTImageFilter_hxx

#include "itkVnlRealToHalfHermitianForwardFFTImageFilter.h"

#if defined( ITK_USE_FFTWD ) || defined( ITK_USE_FFTWF )
#include "itkFFTWRealToHalfHermitianForwardFFTImageFilter.h"
#endif

namespace itk
{

template< typename TSelfPointer, typename TInputImage, typename TOutputImage, typename TPixel >
struct DispatchFFTW_R2C_New
{
  static TSelfPointer Apply()
    {
      return VnlRealToHalfHermitianForwardFFTImageFilter< TInputImage, TOutputImage >
        ::New().GetPointer();
    }
};

#ifdef ITK_USE_FFTWD
template< typename TSelfPointer, typename TInputImage, typename TOutputImage >
struct DispatchFFTW_R2C_New< TSelfPointer, TInputImage, TOutputImage, double >
{
  static TSelfPointer Apply()
    {
      return FFTWRealToHalfHermitianForwardFFTImageFilter< TInputImage, TOutputImage >
        ::New().GetPointer();
    }
};
#endif

#ifdef ITK_USE_FFTWF
template< typename TSelfPointer, typename TInputImage, typename TOutputImage >
struct DispatchFFTW_R2C_New< TSelfPointer, TInputImage, TOutputImage, float >
{
  static TSelfPointer Apply()
    {
      return FFTWRealToHalfHermitianForwardFFTImageFilter< TInputImage, TOutputImage >
        ::New().GetPointer();
    }
};
#endif

template< typename TInputImage, typename TOutputImage >
typename RealToHalfHermitianForwardFFTImageFilter< TInputImage, TOutputImage >::Pointer
RealToHalfHermitianForwardFFTImageFilter< TInputImage, TOutputImage >
::New(void)
{
  Pointer smartPtr = ::itk::ObjectFactory< Self >::Create();

  if ( smartPtr.IsNull() )
    {
    smartPtr = DispatchFFTW_R2C_New< Pointer, TInputImage, TOutputImage,
                                     typename NumericTraits< OutputPixelType >::ValueType >
      ::Apply();
    }

  return smartPtr;
}

template< typename TInputImage, typename TOutputImage >
void
RealToHalfHermitianForwardFFTImageFilter< TInputImage, TOutputImage >
::GenerateOutputInformation()
{
  // Get pointers to the input and output.
  typename InputImageType::ConstPointer inputPtr  = this->GetInput();
  typename OutputImageType::Pointer outputPtr = this->GetOutput();

  if ( !inputPtr || !outputPtr )
    {
    return;
    }

  // This is all based on the same function in itk::ShrinkImageFilter
  // ShrinkImageFilter also modifies the image spacing, but spacing
  // has no meaning in the result of an FFT.
  const InputSizeType inputSize = inputPtr->GetLargestPossibleRegion().GetSize();
  const InputIndexType inputStartIndex = inputPtr->GetLargestPossibleRegion().GetIndex();

  OutputSizeType outputSize;
  OutputIndexType outputStartIndex;

  // In 4.3.4 of the FFTW documentation, they indicate the size of
  // of a real-to-complex FFT is N * N ... + (N /2+1)
  //                              1   2        d
  // complex numbers.
  // static_cast probably not necessary but want to make sure integer
  // division is used.
  outputSize[0] = static_cast< unsigned int >( inputSize[0] ) / 2 + 1;
  outputStartIndex[0] = inputStartIndex[0];

  for ( unsigned int i = 1; i < OutputImageType::ImageDimension; i++ )
    {
    outputSize[i] = inputSize[i];
    outputStartIndex[i] = inputStartIndex[i];
    }

  typename OutputImageType::RegionType outputLargestPossibleRegion;
  outputLargestPossibleRegion.SetSize( outputSize );
  outputLargestPossibleRegion.SetIndex( outputStartIndex );

  outputPtr->SetLargestPossibleRegion( outputLargestPossibleRegion );
}

template< typename TInputImage, typename TOutputImage >
void
RealToHalfHermitianForwardFFTImageFilter< TInputImage, TOutputImage >
::GenerateInputRequestedRegion()
{
  // Call the superclass implementation of this method.
  Superclass::GenerateInputRequestedRegion();

  // Get pointer to the input.
  typename InputImageType::Pointer input  =
    const_cast< InputImageType * >( this->GetInput() );

  if ( !input )
    {
    return;
    }

  input->SetRequestedRegionToLargestPossibleRegion();
}

template< typename TInputImage, typename TOutputImage >
void
RealToHalfHermitianForwardFFTImageFilter< TInputImage, TOutputImage >
::EnlargeOutputRequestedRegion(DataObject *output)
{
  Superclass::EnlargeOutputRequestedRegion(output);
  output->SetRequestedRegionToLargestPossibleRegion();
}
}
#endif
