105 lines
3.5 KiB
C++
105 lines
3.5 KiB
C++
/*
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* Copyright (C) 2015 Tim Mayberry <mojofunk@gmail.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef PBD_WINDOWS_TIMER_UTILS_H
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#define PBD_WINDOWS_TIMER_UTILS_H
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#include <stdint.h>
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#include "pbd/libpbd_visibility.h"
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namespace PBD {
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namespace MMTIMERS {
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/**
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* Get the minimum Multimedia Timer resolution as supported by the system
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* @return true if getting min timer resolution was not successful
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*/
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bool LIBPBD_API get_min_resolution (uint32_t& timer_resolution_ms);
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/**
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* Set the minimum Multimedia Timer resolution as supported by the system
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* @return true if setting min timer resolution was successful
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*/
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bool LIBPBD_API set_min_resolution ();
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/**
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* Set current Multimedia Timer resolution. If the timer resolution has already
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* been set then reset_resolution() must be called before set_resolution will
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* succeed.
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* @return true if setting the timer value was successful, false if setting the
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* timer resolution failed or the resolution has already been set.
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*/
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bool LIBPBD_API set_resolution(uint32_t timer_resolution_ms);
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/**
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* Reset Multimedia Timer resolution. In my testing, if the timer resolution is
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* set below the default, then resetting the resolution will not reset the
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* timer resolution back to 15ms. At least it does not reset immediately
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* even after calling Sleep.
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* @return true if setting the timer value was successful
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*/
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bool LIBPBD_API reset_resolution();
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} // namespace MMTIMERS
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namespace QPC {
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/**
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* Initialize the QPC timer, must be called before QPC::get_microseconds will
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* return a valid value.
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* @return true if QPC timer is usable, use check_timer_valid to try to check
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* if it is monotonic.
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*/
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bool LIBPBD_API initialize ();
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/**
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* @return true if QueryPerformanceCounter is usable as a timer source
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* This should always return true for systems > XP as those versions of windows
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* have there own tests to check timer validity and will select an appropriate
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* timer source. This check is not conclusive and there are probably conditions
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* under which this check will return true but the timer is not monotonic.
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*/
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bool LIBPBD_API check_timer_valid ();
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/**
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* @return the value of the performance counter converted to microseconds
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*
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* If initialize returns true then get_microseconds will always return a
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* positive value. If QPC is not supported(OS < XP) then -1 is returned but the
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* MS docs say that this won't occur for systems >= XP.
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*/
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int64_t LIBPBD_API get_microseconds ();
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} // namespace QPC
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/**
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* The highest resolution timer source provided by the system. On Vista and
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* above this is the value returned by QueryPerformanceCounter(QPC). On XP,
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* this will QPC if supported or otherwise g_get_monotonic_time will be used.
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*
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* @return A timer value in microseconds or -1 in the event that the reading
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* the timer source fails.
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*/
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int64_t LIBPBD_API get_microseconds ();
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} // namespace PBD
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#endif // PBD_WINDOWS_TIMER_UTILS_H
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