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:
  DEFINE_CLASS_NAME("time_stamp");
 
  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 void fill_timeval_ms(timeval &time_point, int milliseconds);
 
private:
  time_representation c_stamp;  
 
  void fill_in_time();  
 
  static time_representation get_time_now();
 
  static rollover_record &rollover_rover();
};
 
} //namespace.
 
#endif