| 1 | #pragma once
|
|---|
| 2 |
|
|---|
| 3 | #include <boost/asio.hpp>
|
|---|
| 4 | #include <boost/chrono.hpp>
|
|---|
| 5 |
|
|---|
| 6 | namespace boost {
|
|---|
| 7 | namespace asio {
|
|---|
| 8 |
|
|---|
| 9 | /**
|
|---|
| 10 | Extension to boost::asio to allow use of a monotonic clock via boost::chrono::steady_clock with the
|
|---|
| 11 | asio::basic_deadline_timer. Monotonic clocks are immune to adjustments of the system clock.
|
|---|
| 12 | The underlying clock and time_type are chrono::steady_clock, but the durations are in posix_time::time_duration
|
|---|
| 13 | in order to achieve a uniform and familiar interface.
|
|---|
| 14 | */
|
|---|
| 15 | template <>
|
|---|
| 16 | struct time_traits<boost::chrono::steady_clock>
|
|---|
| 17 | {
|
|---|
| 18 | /**
|
|---|
| 19 | The underlying time type is based on chrono::steady_clock's time_point.
|
|---|
| 20 | */
|
|---|
| 21 | typedef boost::chrono::steady_clock::time_point time_type;
|
|---|
| 22 |
|
|---|
| 23 | /**
|
|---|
| 24 | But the duration is based upon posix_time's time_duration, just like the ASIO built-in deadline_timer.
|
|---|
| 25 | */
|
|---|
| 26 | typedef boost::posix_time::time_duration duration_type;
|
|---|
| 27 |
|
|---|
| 28 | /**
|
|---|
| 29 | Accessing the clock yields the current time from the steady_clock.
|
|---|
| 30 | */
|
|---|
| 31 | static time_type now()
|
|---|
| 32 | {
|
|---|
| 33 | return boost::chrono::steady_clock::now();
|
|---|
| 34 | }
|
|---|
| 35 |
|
|---|
| 36 | /**
|
|---|
| 37 | Form a new time point (in Chrono) by adding in a time_duration (from posix_time), using the thing they have in
|
|---|
| 38 | common -- microseconds.
|
|---|
| 39 | */
|
|---|
| 40 | static time_type add(const time_type& time, const duration_type& duration)
|
|---|
| 41 | {
|
|---|
| 42 | return time + boost::chrono::microseconds(duration.total_microseconds());
|
|---|
| 43 | }
|
|---|
| 44 |
|
|---|
| 45 | /**
|
|---|
| 46 | Subtract two time points (in Chrono) to yield a time_duration (from posix_time), using the thing they have in
|
|---|
| 47 | common -- microseconds.
|
|---|
| 48 | */
|
|---|
| 49 | static duration_type subtract(const time_type& timeLhs, const time_type& timeRhs)
|
|---|
| 50 | {
|
|---|
| 51 | boost::chrono::microseconds oChronoDuration_us(
|
|---|
| 52 | boost::chrono::duration_cast<boost::chrono::microseconds>(timeLhs - timeRhs));
|
|---|
| 53 | return boost::posix_time::microseconds(oChronoDuration_us.count());
|
|---|
| 54 | }
|
|---|
| 55 |
|
|---|
| 56 | /**
|
|---|
| 57 | Test whether one chrono time is less than another.
|
|---|
| 58 | */
|
|---|
| 59 | static bool less_than(const time_type& timeLhs, const time_type& timeRhs)
|
|---|
| 60 | {
|
|---|
| 61 | return timeLhs < timeRhs;
|
|---|
| 62 | }
|
|---|
| 63 |
|
|---|
| 64 | /**
|
|---|
| 65 | Convert to posix_time::time_duration type, since this is what ASIO needs under the hood. Since we're already
|
|---|
| 66 | representing durations in posix_time::time_duration, this is a mere pass-through.
|
|---|
| 67 | */
|
|---|
| 68 | static boost::posix_time::time_duration to_posix_duration(const duration_type& duration)
|
|---|
| 69 | {
|
|---|
| 70 | return duration;
|
|---|
| 71 | }
|
|---|
| 72 | };
|
|---|
| 73 |
|
|---|
| 74 | /**
|
|---|
| 75 | Convenience typedef for pairing the steady_clock time_traits (above) with a basic_deadline_timer yielding
|
|---|
| 76 | a ready-to-use deadline timer that is based on a monotonic time that is immune to system clock changes.
|
|---|
| 77 | A Boosty name has been chosen, as it is expected that in the near future boost::asio will have this built in.
|
|---|
| 78 | */
|
|---|
| 79 | typedef boost::asio::basic_deadline_timer<boost::chrono::steady_clock> monotonic_deadline_timer;
|
|---|
| 80 |
|
|---|
| 81 | } // namespace asio
|
|---|
| 82 | } // namespace boost
|
|---|
