conditional_ostream.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2004 - 2018 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_conditional_ostream_h
#define dealii_conditional_ostream_h

#include <deal.II/base/config.h>

#include <ostream>

DEAL_II_NAMESPACE_OPEN


class ConditionalOStream
{
public:
  ConditionalOStream(std::ostream &stream, const bool active = true);

  void
  set_condition(const bool active);

  bool
  is_active() const;

  std::ostream &
  get_stream() const;

  template <typename T>
  const ConditionalOStream &
  operator<<(const T &t) const;

  const ConditionalOStream &
  operator<<(std::ostream &(*p)(std::ostream &)) const;

private:
  std::ostream &output_stream;

  bool active_flag;
};


// --------------------------- inline and template functions -----------

template <class T>
inline const ConditionalOStream &
ConditionalOStream::operator<<(const T &t) const
{
  if (active_flag == true)
    output_stream << t;

  return *this;
}


inline const ConditionalOStream &
ConditionalOStream::operator<<(std::ostream &(*p)(std::ostream &)) const
{
  if (active_flag == true)
    output_stream << p;

  return *this;
}


inline std::ostream &
ConditionalOStream::get_stream() const
{
  return output_stream;
}


DEAL_II_NAMESPACE_CLOSE

#endif