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