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