// -*- C++ -*-

//=============================================================================
/**
 *  @file    Countdown_Time.h
 *
 *  $Id$
 *
 *  @author Douglas C. Schmidt <schmidt@cs.wustl.edu>
 */
//=============================================================================

#ifndef ACE_COUNTDOWN_TIME_H
#define ACE_COUNTDOWN_TIME_H

#include /**/ "ace/pre.h"

#include /**/ "ace/ACE_export.h"

#if !defined (ACE_LACKS_PRAGMA_ONCE)
# pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

#include "ace/Time_Value.h"

ACE_BEGIN_VERSIONED_NAMESPACE_DECL

/**
 * @class ACE_Countdown_Time
 *
 * @brief Keeps track of the amount of elapsed time.
 *
 * This class has a side-effect on the @c max_wait_time -- every
 * time the <stop> method is called the <max_wait_time> is
 * updated.
 */
class ACE_Export ACE_Countdown_Time
{
public:
  // = Initialization and termination methods.
  /// Cache the @a max_wait_time and call @c start().
  ACE_Countdown_Time (ACE_Time_Value *max_wait_time);

  /// Destructor, makes sure the max_wait_time that got passed as pointer
  /// to the constructor is updated with the time elapsed.
  ~ACE_Countdown_Time (void);

  /// Cache the current time and enter a start state.
  void start (void);

  /// Subtract the elapsed time from max_wait_time_ and enter a stopped
  /// state.
  void stop (void);

  /// Calls stop and then start.  max_wait_time_ is modified by the
  /// call to stop.
  void update (void);

  /// Returns true if we've already been stopped, else false.
  bool stopped (void) const;

private:
  /// Maximum time we were willing to wait.
  ACE_Time_Value *max_wait_time_;

  /// Beginning of the start time.
  ACE_Time_Value start_time_;

  /// Keeps track of whether we've already been stopped.
  bool stopped_;

  // Prevent copying
  ACE_Countdown_Time (const ACE_Countdown_Time &);
  ACE_Countdown_Time &operator= (const ACE_Countdown_Time &);
};

ACE_END_VERSIONED_NAMESPACE_DECL

#include /**/ "ace/post.h"

#endif /* ACE_COUNTDOWN_TIME_H */