williamr@2: //  boost timer.hpp header file  ---------------------------------------------//
williamr@2: 
williamr@2: //  Copyright Beman Dawes 1994-99.  Distributed under the Boost
williamr@2: //  Software License, Version 1.0. (See accompanying file
williamr@2: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
williamr@2: 
williamr@2: //  See http://www.boost.org/libs/timer for documentation.
williamr@2: 
williamr@2: //  Revision History
williamr@2: //  01 Apr 01  Modified to use new <boost/limits.hpp> header. (JMaddock)
williamr@2: //  12 Jan 01  Change to inline implementation to allow use without library
williamr@2: //             builds. See docs for more rationale. (Beman Dawes) 
williamr@2: //  25 Sep 99  elapsed_max() and elapsed_min() added (John Maddock)
williamr@2: //  16 Jul 99  Second beta
williamr@2: //   6 Jul 99  Initial boost version
williamr@2: 
williamr@2: #ifndef BOOST_TIMER_HPP
williamr@2: #define BOOST_TIMER_HPP
williamr@2: 
williamr@2: #include <boost/config.hpp>
williamr@2: #include <ctime>
williamr@2: #include <boost/limits.hpp>
williamr@2: 
williamr@2: # ifdef BOOST_NO_STDC_NAMESPACE
williamr@2:     namespace std { using ::clock_t; using ::clock; }
williamr@2: # endif
williamr@2: 
williamr@2: 
williamr@2: namespace boost {
williamr@2: 
williamr@2: //  timer  -------------------------------------------------------------------//
williamr@2: 
williamr@2: //  A timer object measures elapsed time.
williamr@2: 
williamr@2: //  It is recommended that implementations measure wall clock rather than CPU
williamr@2: //  time since the intended use is performance measurement on systems where
williamr@2: //  total elapsed time is more important than just process or CPU time.
williamr@2: 
williamr@2: //  Warnings: The maximum measurable elapsed time may well be only 596.5+ hours
williamr@2: //  due to implementation limitations.  The accuracy of timings depends on the
williamr@2: //  accuracy of timing information provided by the underlying platform, and
williamr@2: //  this varies a great deal from platform to platform.
williamr@2: 
williamr@2: class timer
williamr@2: {
williamr@2:  public:
williamr@2:          timer() { _start_time = std::clock(); } // postcondition: elapsed()==0
williamr@2: //         timer( const timer& src );      // post: elapsed()==src.elapsed()
williamr@2: //        ~timer(){}
williamr@2: //  timer& operator=( const timer& src );  // post: elapsed()==src.elapsed()
williamr@2:   void   restart() { _start_time = std::clock(); } // post: elapsed()==0
williamr@2:   double elapsed() const                  // return elapsed time in seconds
williamr@2:     { return  double(std::clock() - _start_time) / CLK_TCK; }
williamr@2: 
williamr@2:   double elapsed_max() const   // return estimated maximum value for elapsed()
williamr@2:   // Portability warning: elapsed_max() may return too high a value on systems
williamr@2:   // where std::clock_t overflows or resets at surprising values.
williamr@2:   {
williamr@2:     return (double((std::numeric_limits<std::clock_t>::max)())
williamr@2:        - double(_start_time)) / double(CLK_TCK); 
williamr@2:   }
williamr@2: 
williamr@2:   double elapsed_min() const            // return minimum value for elapsed()
williamr@2:    { return double(1)/double(CLK_TCK); }
williamr@2: 
williamr@2:  private:
williamr@2:   std::clock_t _start_time;
williamr@2: }; // timer
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #endif  // BOOST_TIMER_HPP