time_stamp.h

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#ifndef TIME_STAMP_CLASS
#define TIME_STAMP_CLASS

/*****************************************************************************\
*                                                                             *
*  Name   : time_stamp                                                        *
*  Author : Chris Koeritz                                                     *
*                                                                             *
*******************************************************************************
* Copyright (c) 1995-$now By Author.  This program 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 2 of   *
* the License or (at your option) any later version.  This is online at:      *
*     http://www.fsf.org/copyleft/gpl.html                                    *
* Please send any updates to: fred@gruntose.com                               *
\*****************************************************************************/

#include <basis/astring.h>
#include <basis/contracts.h>
#include <basis/definitions.h>

// forward.
class rollover_record;
struct timeval;

namespace timely {


class time_stamp : public virtual basis::orderable
{
public:
  typedef double time_representation;

  time_stamp();

  time_stamp(time_representation offset);

  static double rolling_uptime();

  void reset();
  void reset(time_representation offset);

  time_representation value() const { return c_stamp; }

  enum stamp_display_style { STAMP_RELATIVE, STAMP_ABSOLUTE };

  basis::astring text_form(stamp_display_style style = STAMP_RELATIVE) const;

  static basis::astring notarize(bool add_space = true);

  // standard operators: keep in mind that time is represented by an ever
  // increasing number.  so, if a value A is less than a value B, that means
  // that A is older than B, since it occurred at an earlier time.
  virtual bool less_than(const basis::orderable &that) const {
    const time_stamp *cast = dynamic_cast<const time_stamp *>(&that);
    if (!cast) return false;
    return c_stamp < cast->c_stamp;
  }

  virtual bool equal_to(const basis::equalizable &that) const {
    const time_stamp *cast = dynamic_cast<const time_stamp *>(&that);
    if (!cast) return false;
    return c_stamp == cast->c_stamp;
  }

  // helper functions for using the OS's time support.

  static timeval fill_timeval_ms(int milliseconds);

private:
  time_representation c_stamp;  

  void fill_in_time();  

  static time_representation get_time_now();

  static rollover_record &rollover_rover();
};

} //namespace.

#endif