tty-progress.h

// tty-progress.h -- Progress indicator for terminals
//
//  Copyright (C) 2006, 2007, 2010, 2011  Miles Bader <miles@gnu.org>
//
// This source code is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 3, or (at
// your option) any later version.  See the file COPYING for more details.
//
// Written by Miles Bader <miles@gnu.org>
//

#ifndef SNOGRAY_TTY_PROGRESS_H
#define SNOGRAY_TTY_PROGRESS_H


#include <iosfwd>
#include <string>

#include "timeval.h"

#include "progress.h"


namespace snogray {


// A progress indicator for terminals.
//
class TtyProgress : public Progress
{
public:

  enum Verbosity { QUIET, MINIMAL, CHATTY };

  static float default_update_interval () { return 10; }
  static float startup_interval () { return 20; }

  // Initialize with the desired bounds.  Note that nothing actually
  // happens until the `start' method is called.
  //
  TtyProgress (std::ostream &stream, const std::string &_prefix,
	       Verbosity _verbosity = CHATTY,
	       float _update_interval = default_update_interval())
    : prefix (_prefix),
      start_pos (0), end_pos (0),
      last_pos (0), last_update_time (0), update_pos (0),
      ticks_until_forced_update (0), start_time (0),
      verbosity (_verbosity), os (stream),
      update_interval (_update_interval)
  { }

  // Set the start position of the progress range; positions before
  // this are not counted as progress.  This is normally called before
  // Progress::start, but may be called afterwards and should do
  // something reasonable.
  //
  virtual void set_start (int pos);

  // Set the size of the progress range, following the start position.
  // This is normally called before Progress::start, but may be called
  // afterwards and should do something reasonable.
  //
  virtual void set_size (unsigned size);

  // Start displaying the progress indicator.
  //
  virtual void start ();

  // Update the progress indicator to position POS.
  //
  virtual void update (int pos);

  // Finish the progress indicator.
  //
  virtual void end ();

private:

  // Prefix string printed on the progress line.
  //
  std::string prefix;

  // Overall rendering bounds
  //
  int start_pos, end_pos;

  // When we last updated the progress indicator
  //
  int last_pos;
  Timeval last_update_time;

  // When we will next update it
  //
  int update_pos;

  // After this many calls to Progress::update, an update will be forced
  // even if the position hasn't changed much.
  //
  unsigned ticks_until_forced_update;

  // When we started
  //
  Timeval start_time;

  // How chatty to be
  //
  Verbosity verbosity;

  // Where to send progress reports to
  //
  std::ostream &os;

  // How often (approximately) to update (in seconds)
  //
  Timeval update_interval;
};


}

#endif // SNOGRAY_TTY_PROGRESS_H


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