//============================================================
//
//  wintime.c - Win32 OSD core timing functions
//
//============================================================
//
//  Copyright Aaron Giles
//  All rights reserved.
//
//  Redistribution and use in source and binary forms, with or
//  without modification, are permitted provided that the
//  following conditions are met:
//
//    * Redistributions of source code must retain the above
//      copyright notice, this list of conditions and the
//      following disclaimer.
//    * Redistributions in binary form must reproduce the
//      above copyright notice, this list of conditions and
//      the following disclaimer in the documentation and/or
//      other materials provided with the distribution.
//    * Neither the name 'MAME' nor the names of its
//      contributors may be used to endorse or promote
//      products derived from this software without specific
//      prior written permission.
//
//  THIS SOFTWARE IS PROVIDED BY AARON GILES ''AS IS'' AND
//  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
//  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
//  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
//  EVENT SHALL AARON GILES BE LIABLE FOR ANY DIRECT,
//  INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
//  DAMAGE (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
//  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
//  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
//  ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
//  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
//  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
//  IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//============================================================

// standard windows headers
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <mmsystem.h>

// MAME headers
#include "osdepend.h"



//============================================================
//  GLOBAL VARIABLES
//============================================================

static osd_ticks_t ticks_per_second = 0;
static osd_ticks_t suspend_ticks = 0;
static BOOL using_qpc = TRUE;



//============================================================
//  osd_ticks
//============================================================

osd_ticks_t osd_ticks(void)
{
	LARGE_INTEGER performance_count;

	// if we're suspended, just return that
	if (suspend_ticks != 0)
		return suspend_ticks;

	// if we have a per second count, just go for it
	if (ticks_per_second != 0)
	{
		// QueryPerformanceCounter if we can
		if (using_qpc)
		{
			QueryPerformanceCounter(&performance_count);
			return (osd_ticks_t)performance_count.QuadPart - suspend_ticks;
		}

		// otherwise, fall back to timeGetTime
		else
			return (osd_ticks_t)timeGetTime() - suspend_ticks;
	}

	// if not, we have to determine it
	using_qpc = QueryPerformanceFrequency(&performance_count) && (performance_count.QuadPart != 0);
	if (using_qpc)
		ticks_per_second = (osd_ticks_t)performance_count.QuadPart;
	else
		ticks_per_second = 1000;

	// call ourselves to get the first value
	return osd_ticks();
}


//============================================================
//  osd_ticks_per_second
//============================================================

osd_ticks_t osd_ticks_per_second(void)
{
	return ticks_per_second;
}


//============================================================
//  osd_sleep
//============================================================

void osd_sleep(osd_ticks_t duration)
{
	DWORD msec;

	// make sure we've computed ticks_per_second
	if (ticks_per_second == 0)
		(void)osd_ticks();

	// convert to milliseconds, rounding down
	msec = (DWORD)(duration * 1000 / ticks_per_second);

	// only sleep if at least 2 full milliseconds
	if (msec >= 2)
	{
		HANDLE current_thread = GetCurrentThread();
		int old_priority = GetThreadPriority(current_thread);

		// take a couple of msecs off the top for good measure
		msec -= 2;

		// bump our thread priority super high so that we get
		// priority when we need it
		SetThreadPriority(current_thread, THREAD_PRIORITY_TIME_CRITICAL);
		Sleep(msec);
		SetThreadPriority(current_thread, old_priority);
	}
}
