/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  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
 *
 *         https://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 itkImageRegionConstIteratorWithIndex_hxx
#define itkImageRegionConstIteratorWithIndex_hxx


namespace itk
{
//----------------------------------------------------------------------
//  Advance along the line
//----------------------------------------------------------------------
template <typename TImage>
ImageRegionConstIteratorWithIndex<TImage> &
ImageRegionConstIteratorWithIndex<TImage>::operator++()
{
  this->m_Remaining = false;
  for (unsigned int in = 0; in < TImage::ImageDimension; ++in)
  {
    const IndexValueType positionIndex = ++this->m_PositionIndex[in];
    if (positionIndex < this->m_EndIndex[in])
    {
      this->m_Position += this->m_OffsetTable[in];
      this->m_Remaining = true;
      break;
    }

    this->m_Position -= this->m_OffsetTable[in] * (static_cast<OffsetValueType>(this->m_Region.GetSize()[in]) - 1);
    this->m_PositionIndex[in] = this->m_BeginIndex[in];
  }

  if (!this->m_Remaining) // It will not advance here otherwise
  {
    this->m_Position = this->m_End;
  }

  return *this;
}

//----------------------------------------------------------------------
//  Advance along the line in reverse direction
//----------------------------------------------------------------------
template <typename TImage>
ImageRegionConstIteratorWithIndex<TImage> &
ImageRegionConstIteratorWithIndex<TImage>::operator--()
{
  this->m_Remaining = false;
  for (unsigned int in = 0; in < TImage::ImageDimension; ++in)
  {
    if (this->m_PositionIndex[in] > this->m_BeginIndex[in])
    {
      this->m_PositionIndex[in]--;
      this->m_Position -= this->m_OffsetTable[in];
      this->m_Remaining = true;
      break;
    }

    this->m_Position += this->m_OffsetTable[in] * (static_cast<OffsetValueType>(this->m_Region.GetSize()[in]) - 1);
    this->m_PositionIndex[in] = this->m_EndIndex[in] - 1;
  }

  if (!this->m_Remaining) // It will not advance here otherwise
  {
    this->m_Position = this->m_End;
  }

  return *this;
}
} // end namespace itk

#endif
