/*=========================================================================
 *
 *  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 itkMRCImageIOPrivate_h
#define itkMRCImageIOPrivate_h

#include <utility>

/*
 *  This code was contributed in the Insight Journal paper:
 *  "A Streaming IO Base Class and Support for Streaming the MRC and VTK File Format"
 *  by Lowekamp B., Chen D.
 *  https://www.insight-journal.org/browse/publication/729
 *
 */

namespace itk
{

namespace
{

const char * const magicMAP = "MAP ";

///////////////////////////////////////////////////

///////////////////////////////////////////////////
// Generic Programming Algorithms
///////////////////////////////////////////////////

/// \brief returns the min and max of a sequence defined by two iterators
///
/// Uses the < operator to determine ordering.
/// If first == last then return is pair(first,first).
/// Otherwise it is pair(min, max).
template <typename TInputIter>
inline std::pair<TInputIter, TInputIter>
min_max_element(TInputIter first, TInputIter last)
{
  std::pair<TInputIter, TInputIter> result(first, first);

  if (first == last)
  {
    return result;
  }

  while (++first != last)
  {
    TInputIter prev = first;
    if (++first == last)
    {
      if (*prev < *(result.first))
      {
        result.first = prev;
      }
      if (*(result.second) < *prev)
      {
        result.second = prev;
      }
      break;
    }
    else if (*first < *prev)
    {
      if (*first < *(result.first))
      {
        result.first = first;
      }
      if (*(result.second) < *prev)
      {
        result.second = prev;
      }
    }
    else
    {
      if (*prev < *(result.first))
      {
        result.first = prev;
      }
      if (*(result.second) < *first)
      {
        result.second = first;
      }
    }
  }
  return result;
}

} // end anonymous namespace

} // namespace itk

#endif // itkMRCImageIOPrivate_h