Chris@16: //  boost timer.hpp header file  ---------------------------------------------//
Chris@16: 
Chris@16: //  Copyright Beman Dawes 1994-99.  Distributed under the Boost
Chris@16: //  Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  See http://www.boost.org/libs/timer for documentation.
Chris@16: 
Chris@16: //  Revision History
Chris@16: //  01 Apr 01  Modified to use new <boost/limits.hpp> header. (JMaddock)
Chris@16: //  12 Jan 01  Change to inline implementation to allow use without library
Chris@16: //             builds. See docs for more rationale. (Beman Dawes) 
Chris@16: //  25 Sep 99  elapsed_max() and elapsed_min() added (John Maddock)
Chris@16: //  16 Jul 99  Second beta
Chris@16: //   6 Jul 99  Initial boost version
Chris@16: 
Chris@16: #ifndef BOOST_TIMER_HPP
Chris@16: #define BOOST_TIMER_HPP
Chris@16: 
Chris@16: #include <boost/config.hpp>
Chris@16: #include <ctime>
Chris@16: #include <boost/limits.hpp>
Chris@16: 
Chris@16: # ifdef BOOST_NO_STDC_NAMESPACE
Chris@16:     namespace std { using ::clock_t; using ::clock; }
Chris@16: # endif
Chris@16: 
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: //  timer  -------------------------------------------------------------------//
Chris@16: 
Chris@16: //  A timer object measures elapsed time.
Chris@16: 
Chris@16: //  It is recommended that implementations measure wall clock rather than CPU
Chris@16: //  time since the intended use is performance measurement on systems where
Chris@16: //  total elapsed time is more important than just process or CPU time.
Chris@16: 
Chris@16: //  Warnings: The maximum measurable elapsed time may well be only 596.5+ hours
Chris@16: //  due to implementation limitations.  The accuracy of timings depends on the
Chris@16: //  accuracy of timing information provided by the underlying platform, and
Chris@16: //  this varies a great deal from platform to platform.
Chris@16: 
Chris@16: class timer
Chris@16: {
Chris@16:  public:
Chris@16:          timer() { _start_time = std::clock(); } // postcondition: elapsed()==0
Chris@16: //         timer( const timer& src );      // post: elapsed()==src.elapsed()
Chris@16: //        ~timer(){}
Chris@16: //  timer& operator=( const timer& src );  // post: elapsed()==src.elapsed()
Chris@16:   void   restart() { _start_time = std::clock(); } // post: elapsed()==0
Chris@16:   double elapsed() const                  // return elapsed time in seconds
Chris@16:     { return  double(std::clock() - _start_time) / CLOCKS_PER_SEC; }
Chris@16: 
Chris@16:   double elapsed_max() const   // return estimated maximum value for elapsed()
Chris@16:   // Portability warning: elapsed_max() may return too high a value on systems
Chris@16:   // where std::clock_t overflows or resets at surprising values.
Chris@16:   {
Chris@16:     return (double((std::numeric_limits<std::clock_t>::max)())
Chris@16:        - double(_start_time)) / double(CLOCKS_PER_SEC); 
Chris@16:   }
Chris@16: 
Chris@16:   double elapsed_min() const            // return minimum value for elapsed()
Chris@16:    { return double(1)/double(CLOCKS_PER_SEC); }
Chris@16: 
Chris@16:  private:
Chris@16:   std::clock_t _start_time;
Chris@16: }; // timer
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif  // BOOST_TIMER_HPP