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.hpp> |
21 | #include <ctime> |
22 | #include <boost/limits.hpp> |
23 | |
24 | # ifdef BOOST_NO_STDC_NAMESPACE |
25 | namespace std { using ::clock_t; using ::clock; } |
26 | # endif |
27 | |
28 | |
29 | namespace boost { |
30 | |
31 | // timer -------------------------------------------------------------------// |
32 | |
33 | // A timer object measures elapsed time. |
34 | |
35 | // It is recommended that implementations measure wall clock rather than CPU |
36 | // time since the intended use is performance measurement on systems where |
37 | // total elapsed time is more important than just process or CPU time. |
38 | |
39 | // Warnings: The maximum measurable elapsed time may well be only 596.5+ hours |
40 | // due to implementation limitations. The accuracy of timings depends on the |
41 | // accuracy of timing information provided by the underlying platform, and |
42 | // this varies a great deal from platform to platform. |
43 | |
44 | class timer |
45 | { |
46 | public: |
47 | timer() { _start_time = std::clock(); } // postcondition: elapsed()==0 |
48 | // timer( const timer& src ); // post: elapsed()==src.elapsed() |
49 | // ~timer(){} |
50 | // timer& operator=( const timer& src ); // post: elapsed()==src.elapsed() |
51 | void restart() { _start_time = std::clock(); } // post: elapsed()==0 |
52 | double elapsed() const // return elapsed time in seconds |
53 | { return double(std::clock() - _start_time) / CLOCKS_PER_SEC; } |
54 | |
55 | double elapsed_max() const // return estimated maximum value for elapsed() |
56 | // Portability warning: elapsed_max() may return too high a value on systems |
57 | // where std::clock_t overflows or resets at surprising values. |
58 | { |
59 | return (double((std::numeric_limits<std::clock_t>::max)()) |
60 | - double(_start_time)) / double(CLOCKS_PER_SEC); |
61 | } |
62 | |
63 | double elapsed_min() const // return minimum value for elapsed() |
64 | { return double(1)/double(CLOCKS_PER_SEC); } |
65 | |
66 | private: |
67 | std::clock_t _start_time; |
68 | }; // timer |
69 | |
70 | } // namespace boost |
71 | |
72 | #endif // BOOST_TIMER_HPP |
73 | |