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Diffstat (limited to 'boost/chrono/system_clocks.hpp')
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diff --git a/boost/chrono/system_clocks.hpp b/boost/chrono/system_clocks.hpp new file mode 100644 index 0000000000..bb62610c72 --- /dev/null +++ b/boost/chrono/system_clocks.hpp @@ -0,0 +1,229 @@ +// boost/chrono/system_clocks.hpp --------------------------------------------------------------// + +// Copyright 2008 Howard Hinnant +// Copyright 2008 Beman Dawes +// Copyright 2009-2011 Vicente J. Botet Escriba + +// Distributed under the Boost Software License, Version 1.0. +// See http://www.boost.org/LICENSE_1_0.txt + +/* + +This code was derived by Beman Dawes from Howard Hinnant's time2_demo prototype. +Many thanks to Howard for making his code available under the Boost license. +The original code was modified to conform to Boost conventions and to section +20.9 Time utilities [time] of the C++ committee's working paper N2798. +See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2798.pdf. + +time2_demo contained this comment: + + Much thanks to Andrei Alexandrescu, + Walter Brown, + Peter Dimov, + Jeff Garland, + Terry Golubiewski, + Daniel Krugler, + Anthony Williams. +*/ + +/* + +TODO: + + * Fully implement error handling, with test cases. + * Use boost::throw_exception. (Currently not used because of an issue with Intel 11.0.) + * Consider issues raised by Michael Marcin: + + > In the past I've seen QueryPerformanceCounter give incorrect results, + > especially with SpeedStep processors on laptops. This was many years ago and + > might have been fixed by service packs and drivers. + > + > Typically you check the results of QPC against GetTickCount to see if the + > results are reasonable. + > http://support.microsoft.com/kb/274323 + > + > I've also heard of problems with QueryPerformanceCounter in multi-processor + > systems. + > + > I know some people SetThreadAffinityMask to 1 for the current thread call + > their QueryPerformance* functions then restore SetThreadAffinityMask. This + > seems horrible to me because it forces your program to jump to another + > physical processor if it isn't already on cpu0 but they claim it worked well + > in practice because they called the timing functions infrequently. + > + > In the past I have chosen to use timeGetTime with timeBeginPeriod(1) for + > high resolution timers to avoid these issues. + +*/ + +#ifndef BOOST_CHRONO_SYSTEM_CLOCKS_HPP +#define BOOST_CHRONO_SYSTEM_CLOCKS_HPP + +#include <boost/chrono/config.hpp> +#include <boost/chrono/duration.hpp> +#include <boost/chrono/time_point.hpp> +#if !defined BOOST_CHRONO_DONT_PROVIDE_HYBRID_ERROR_HANDLING +#include <boost/chrono/detail/system.hpp> +#include <boost/system/error_code.hpp> +#endif +#include <boost/chrono/clock_string.hpp> + +#include <ctime> + +#ifdef BOOST_CHRONO_WINDOWS_API +// The system_clock tick is 100 nanoseconds +# define BOOST_SYSTEM_CLOCK_DURATION boost::chrono::duration<boost::int_least64_t, ratio<BOOST_RATIO_INTMAX_C(1), BOOST_RATIO_INTMAX_C(10000000)> > +#else +# define BOOST_SYSTEM_CLOCK_DURATION boost::chrono::nanoseconds +#endif + +#ifndef BOOST_CHRONO_HEADER_ONLY +#include <boost/config/abi_prefix.hpp> // must be the last #include +#endif + + +//----------------------------------------------------------------------------// +// // +// 20.9 Time utilities [time] // +// synopsis // +// // +//----------------------------------------------------------------------------// + +namespace boost { +namespace chrono { + + // Clocks + class BOOST_CHRONO_DECL system_clock; +#ifdef BOOST_CHRONO_HAS_CLOCK_STEADY + class BOOST_CHRONO_DECL steady_clock; +#endif + +#ifdef BOOST_CHRONO_HAS_CLOCK_STEADY + typedef steady_clock high_resolution_clock; // as permitted by [time.clock.hires] +#else + typedef system_clock high_resolution_clock; // as permitted by [time.clock.hires] +#endif + +//----------------------------------------------------------------------------// +// // +// 20.9.5 Clocks [time.clock] // +// // +//----------------------------------------------------------------------------// + +// If you're porting, clocks are the system-specific (non-portable) part. +// You'll need to know how to get the current time and implement that under now(). +// You'll need to know what units (tick period) and representation makes the most +// sense for your clock and set those accordingly. +// If you know how to map this clock to time_t (perhaps your clock is std::time, which +// makes that trivial), then you can fill out system_clock's to_time_t() and from_time_t(). + +//----------------------------------------------------------------------------// +// 20.9.5.1 Class system_clock [time.clock.system] // +//----------------------------------------------------------------------------// + + class BOOST_CHRONO_DECL system_clock + { + public: + typedef BOOST_SYSTEM_CLOCK_DURATION duration; + typedef duration::rep rep; + typedef duration::period period; + typedef chrono::time_point<system_clock> time_point; + BOOST_STATIC_CONSTEXPR bool is_steady = false; + + static BOOST_CHRONO_INLINE time_point now() BOOST_NOEXCEPT; +#if !defined BOOST_CHRONO_DONT_PROVIDE_HYBRID_ERROR_HANDLING + static BOOST_CHRONO_INLINE time_point now(system::error_code & ec); +#endif + + static BOOST_CHRONO_INLINE std::time_t to_time_t(const time_point& t) BOOST_NOEXCEPT; + static BOOST_CHRONO_INLINE time_point from_time_t(std::time_t t) BOOST_NOEXCEPT; + }; + +//----------------------------------------------------------------------------// +// 20.9.5.2 Class steady_clock [time.clock.steady] // +//----------------------------------------------------------------------------// + +// As permitted by [time.clock.steady] +// The class steady_clock is conditionally supported. + +#ifdef BOOST_CHRONO_HAS_CLOCK_STEADY + class BOOST_CHRONO_DECL steady_clock + { + public: + typedef nanoseconds duration; + typedef duration::rep rep; + typedef duration::period period; + typedef chrono::time_point<steady_clock> time_point; + BOOST_STATIC_CONSTEXPR bool is_steady = true; + + static BOOST_CHRONO_INLINE time_point now() BOOST_NOEXCEPT; +#if !defined BOOST_CHRONO_DONT_PROVIDE_HYBRID_ERROR_HANDLING + static BOOST_CHRONO_INLINE time_point now(system::error_code & ec); +#endif + }; +#endif +//----------------------------------------------------------------------------// +// 20.9.5.3 Class high_resolution_clock [time.clock.hires] // +//----------------------------------------------------------------------------// + +// As permitted, steady_clock or system_clock is a typedef for high_resolution_clock. +// See synopsis. + + + template<class CharT> + struct clock_string<system_clock, CharT> + { + static std::basic_string<CharT> name() + { + static const CharT u[] = + { 's', 'y', 's', 't', 'e', 'm', '_', 'c', 'l', 'o', 'c', 'k' }; + static const std::basic_string<CharT> str(u, u + sizeof(u) + / sizeof(u[0])); + return str; + } + static std::basic_string<CharT> since() + { + static const CharT + u[] = + { ' ', 's', 'i', 'n', 'c', 'e', ' ', 'J', 'a', 'n', ' ', '1', ',', ' ', '1', '9', '7', '0' }; + static const std::basic_string<CharT> str(u, u + sizeof(u) + / sizeof(u[0])); + return str; + } + }; + +#ifdef BOOST_CHRONO_HAS_CLOCK_STEADY + + template<class CharT> + struct clock_string<steady_clock, CharT> + { + static std::basic_string<CharT> name() + { + static const CharT + u[] = + { 's', 't', 'e', 'a', 'd', 'y', '_', 'c', 'l', 'o', 'c', 'k' }; + static const std::basic_string<CharT> str(u, u + sizeof(u) + / sizeof(u[0])); + return str; + } + static std::basic_string<CharT> since() + { + const CharT u[] = + { ' ', 's', 'i', 'n', 'c', 'e', ' ', 'b', 'o', 'o', 't' }; + const std::basic_string<CharT> str(u, u + sizeof(u) / sizeof(u[0])); + return str; + } + }; + +#endif + +} // namespace chrono +} // namespace boost + +#ifndef BOOST_CHRONO_HEADER_ONLY +#include <boost/config/abi_suffix.hpp> // pops abi_prefix.hpp pragmas +#else +#include <boost/chrono/detail/inlined/chrono.hpp> +#endif + +#endif // BOOST_CHRONO_SYSTEM_CLOCKS_HPP |