conditional_ostream.h

// ---------------------------------------------------------------------
//
// Copyright (C) 2004 - 2017 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 at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------

#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