4 // Fraunhofer Institute for Open Communication Systems (FOKUS)
5 // Competence Center NETwork research (NET), St. Augustin, GERMANY
6 // Stefan Bund <g0dil@berlios.de>
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 2 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the
20 // Free Software Foundation, Inc.,
21 // 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24 \brief ClockService public header */
26 #ifndef HH_ClockService_
27 #define HH_ClockService_ 1
31 #include <boost/utility.hpp>
32 #include <boost/date_time/posix_time/posix_time.hpp>
33 #include <boost/scoped_ptr.hpp>
34 #include <boost/cstdint.hpp>
35 #include "../Utils/singleton.hh"
37 //#include "ClockService.mpp"
38 ///////////////////////////////hh.p////////////////////////////////////////
43 namespace detail { class ClockServiceTest; }
46 // Implementation note: The clock value is represented as a 64bit unsigned integer number of
47 // nanosecods based on the CLOCK_MONOTONIC POSIX clock.
49 // To allow conversion between clock value and absolute time, the ClockService samples the
50 // absolute current time and the clock value when the conversion is performed. This is done at
51 // most once per second on a if-needed basis.
53 /** \brief Reliable high precision monotonous clock source
55 The ClockService provides a highly accurate monotonous clock source based on
56 gettimeofday(). However, it takes additional precautions to detect clock skew.
58 \implementation The funny mixture of static and non-static members stems from the old
59 implementation based on interval timers and gettimeofday(). The current implementation
60 usses POSIX clocks and is much simpler and more precise.
63 : singleton<ClockService>
66 ///////////////////////////////////////////////////////////////////////////
69 /** \brief ClockService timer data type
71 Unsigned integer type representing scheduler time. Scheduler time is measured in
72 nanoseconds relative to some implementation defined reference time.
74 typedef boost::int_fast64_t clock_type;
76 /** \brief Supplementary integer type
78 This type is used to represent varies supplementary values (e.g. number of microseconds)
80 typedef boost::int_fast64_t int64_type;
82 /** \brief Absolute time data type
84 Boost.DateTime datatype used to represent absolute date/time values.
86 typedef boost::posix_time::ptime abstime_type;
88 ///////////////////////////////////////////////////////////////////////////
90 static clock_type now(); ///< Return current clock value
92 static abstime_type abstime(clock_type clock); ///< Convert clock to absolute time
93 /**< This member converts a clock value into an absolute
95 \note You should not base timeout calculations on this
96 absolute time value. Clock time is guaranteed to be
97 monotonous, absolute time may be non-monotonous if
98 the system date/time is changed. */
100 static clock_type clock(abstime_type time); ///< Convert absolute time to clock value
101 /**< This member converst an absolute time value into the
102 corresponding clock value.
105 static clock_type from_time_t(time_t const & time);
106 ///< Convert legacy time_t to clock value
107 /**< This member converts an absolute time value
108 represented as a time_t value into a clock value */
110 static clock_type from_timeval(timeval const & time);
111 ///< Convert legacy timeval to clock value
112 /**< This member converts an absolute time value
113 represented as a timeval value into a clock value */
115 static clock_type nanoseconds(int64_type v); ///< Convert \a v nanoseconds to clock_type
116 static clock_type microseconds(int64_type v); ///< Convert \a v microseconds to clock_type
117 static clock_type milliseconds(int64_type v); ///< Convert \a v milliseconds to clock_type
118 static clock_type seconds(int64_type v); ///< Convert \a v seconds to clock_type
119 static clock_type minutes(int64_type v); ///< Convert \a v minutes to clock_type
120 static clock_type hours(int64_type v); ///< Convert \a v hours to clock_type
121 static clock_type days(int64_type v); ///< Convert \a v days to clock_type
123 static int64_type in_nanoseconds(clock_type v); ///< Convert \a v to nanoseconds
124 static int64_type in_microseconds(clock_type v); ///< Convert \a v to microseconds
125 static int64_type in_milliseconds(clock_type v); ///< Convert \a v to milliseconds
126 static int64_type in_seconds(clock_type v); ///< Convert \a v to seconds
127 static int64_type in_minutes(clock_type v); ///< Convert \a v to minutes
128 static int64_type in_hours(clock_type v); ///< Convert \a v to hours
129 static int64_type in_days(clock_type v); ///< Convert \a v to days
131 static void restart(); ///< Force re-syncronisation of abstime and clock
132 /**< Calling the member should never be necessary since
133 abstime() / clock() automatically call restart() if
139 abstime_type abstime_m(clock_type clock);
140 clock_type clock_m(abstime_type time);
143 boost::posix_time::ptime baseAbstime_;
144 clock_type baseClock_;
146 /// Internal: ClockService private data (PIMPL idiom)
149 friend class singleton<ClockService>;
155 ///////////////////////////////hh.e////////////////////////////////////////
156 #include "ClockService.cci"
157 //#include "ClockService.ct"
158 //#include "ClockService.cti"
165 // comment-column: 40
166 // c-file-style: "senf"
167 // indent-tabs-mode: nil
168 // ispell-local-dictionary: "american"
169 // compile-command: "scons -u test"