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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 |