1 // boost timer.hpp header file ---------------------------------------------// 2 3 // Copyright Beman Dawes 1994-99. Distributed under the Boost 4 // Software License, Version 1.0. (See accompanying file 5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6 7 // See http://www.boost.org/libs/timer for documentation. 8 9 // Revision History 10 // 01 Apr 01 Modified to use new <boost/limits.hpp> header. (JMaddock) 11 // 12 Jan 01 Change to inline implementation to allow use without library 12 // builds. See docs for more rationale. (Beman Dawes) 13 // 25 Sep 99 elapsed_max() and elapsed_min() added (John Maddock) 14 // 16 Jul 99 Second beta 15 // 6 Jul 99 Initial boost version 16 17 #ifndef BOOST_TIMER_HPP 18 #define BOOST_TIMER_HPP 19 20 #include <boost/config/header_deprecated.hpp> 21 BOOST_HEADER_DEPRECATED( "the facilities in <boost/timer/timer.hpp>" ) 22 23 #include <boost/config.hpp> 24 #include <ctime> 25 #include <boost/limits.hpp> 26 27 # ifdef BOOST_NO_STDC_NAMESPACE 28 namespace std { using ::clock_t; using ::clock; } 29 # endif 30 31 32 namespace boost { 33 34 // timer -------------------------------------------------------------------// 35 36 // A timer object measures elapsed time. 37 38 // It is recommended that implementations measure wall clock rather than CPU 39 // time since the intended use is performance measurement on systems where 40 // total elapsed time is more important than just process or CPU time. 41 42 // Warnings: The maximum measurable elapsed time may well be only 596.5+ hours 43 // due to implementation limitations. The accuracy of timings depends on the 44 // accuracy of timing information provided by the underlying platform, and 45 // this varies a great deal from platform to platform. 46 47 class timer 48 { 49 public: timer()50 timer() { _start_time = std::clock(); } // postcondition: elapsed()==0 51 // timer( const timer& src ); // post: elapsed()==src.elapsed() 52 // ~timer(){} 53 // timer& operator=( const timer& src ); // post: elapsed()==src.elapsed() restart()54 void restart() { _start_time = std::clock(); } // post: elapsed()==0 elapsed() const55 double elapsed() const // return elapsed time in seconds 56 { return double(std::clock() - _start_time) / CLOCKS_PER_SEC; } 57 elapsed_max() const58 double elapsed_max() const // return estimated maximum value for elapsed() 59 // Portability warning: elapsed_max() may return too high a value on systems 60 // where std::clock_t overflows or resets at surprising values. 61 { 62 return (double((std::numeric_limits<std::clock_t>::max)()) 63 - double(_start_time)) / double(CLOCKS_PER_SEC); 64 } 65 elapsed_min() const66 double elapsed_min() const // return minimum value for elapsed() 67 { return double(1)/double(CLOCKS_PER_SEC); } 68 69 private: 70 std::clock_t _start_time; 71 }; // timer 72 73 } // namespace boost 74 75 #endif // BOOST_TIMER_HPP 76