matrix_iterator.h

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// ---------------------------------------------------------------------
//
// Copyright (C) 1999 - 2023 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE.md at
// the top level directory of deal.II.
//
// ---------------------------------------------------------------------
 
#ifndef dealii_matrix_iterator_h
#define dealii_matrix_iterator_h
 
 
#include <deal.II/base/config.h>
 
#include <deal.II/base/exceptions.h>
 
DEAL_II_NAMESPACE_OPEN
 
template <class ACCESSOR>
class MatrixIterator
{
public:
  using size_type = types::global_dof_index;
 
  using MatrixType = typename ACCESSOR::MatrixType;
 
  MatrixIterator(MatrixType *    matrix,
                 const size_type row   = 0,
                 const size_type index = 0);
 
  template <class OtherAccessor>
  MatrixIterator(const MatrixIterator<OtherAccessor> &other);
 
  MatrixIterator &
  operator++();
 
  MatrixIterator
  operator++(int);
 
  const ACCESSOR &
  operator*() const;
 
  const ACCESSOR *
  operator->() const;
 
  template <class OtherAccessor>
  bool
  operator==(const MatrixIterator<OtherAccessor> &) const;
 
  template <class OtherAccessor>
  bool
  operator!=(const MatrixIterator<OtherAccessor> &) const;
 
  bool
  operator<(const MatrixIterator &) const;
 
  bool
  operator>(const MatrixIterator &) const;
 
private:
  ACCESSOR accessor;
 
  // Allow other iterators access to private data.
  template <class OtherAccessor>
  friend class MatrixIterator;
};
 
 
//----------------------------------------------------------------------//
 
template <class ACCESSOR>
inline MatrixIterator<ACCESSOR>::MatrixIterator(MatrixType *    matrix,
                                                const size_type r,
                                                const size_type i)
  : accessor(matrix, r, i)
{}
 
 
template <class ACCESSOR>
template <class OtherAccessor>
inline MatrixIterator<ACCESSOR>::MatrixIterator(
  const MatrixIterator<OtherAccessor> &other)
  : accessor(other.accessor)
{}
 
 
template <class ACCESSOR>
inline MatrixIterator<ACCESSOR> &
MatrixIterator<ACCESSOR>::operator++()
{
  accessor.advance();
  return *this;
}
 
 
template <class ACCESSOR>
inline MatrixIterator<ACCESSOR>
MatrixIterator<ACCESSOR>::operator++(int)
{
  const MatrixIterator iter = *this;
  accessor.advance();
  return iter;
}
 
 
template <class ACCESSOR>
inline const ACCESSOR &
MatrixIterator<ACCESSOR>::operator*() const
{
  return accessor;
}
 
 
template <class ACCESSOR>
inline const ACCESSOR *
MatrixIterator<ACCESSOR>::operator->() const
{
  return &accessor;
}
 
 
template <class ACCESSOR>
template <class OtherAccessor>
inline bool
MatrixIterator<ACCESSOR>::operator==(
  const MatrixIterator<OtherAccessor> &other) const
{
  return (accessor == other.accessor);
}
 
 
template <class ACCESSOR>
template <class OtherAccessor>
inline bool
MatrixIterator<ACCESSOR>::operator!=(
  const MatrixIterator<OtherAccessor> &other) const
{
  return !(*this == other);
}
 
 
template <class ACCESSOR>
inline bool
MatrixIterator<ACCESSOR>::operator<(const MatrixIterator &other) const
{
  Assert(&accessor.get_matrix() == &other.accessor.get_matrix(),
         ExcInternalError());
 
  return (accessor < other.accessor);
}
 
 
template <class ACCESSOR>
inline bool
MatrixIterator<ACCESSOR>::operator>(const MatrixIterator &other) const
{
  return (other < *this);
}
 
DEAL_II_NAMESPACE_CLOSE
 
#endif