SDL-mirror/src/timer/windows/SDL_systimer.c
2011-02-11 22:37:15 -08:00

110 lines
2.8 KiB
C

/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2011 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
*/
#include "SDL_config.h"
#ifdef SDL_TIMER_WINDOWS
#include "../../core/windows/SDL_windows.h"
#include <mmsystem.h>
#include "SDL_timer.h"
#ifdef _WIN32_WCE
#error This is WinCE. Please use src/timer/wince/SDL_systimer.c instead.
#endif
#define TIME_WRAP_VALUE (~(DWORD)0)
/* The first (low-resolution) ticks value of the application */
static DWORD start;
#ifndef USE_GETTICKCOUNT
/* Store if a high-resolution performance counter exists on the system */
static BOOL hires_timer_available;
/* The first high-resolution ticks value of the application */
static LARGE_INTEGER hires_start_ticks;
/* The number of ticks per second of the high-resolution performance counter */
static LARGE_INTEGER hires_ticks_per_second;
#endif
void
SDL_StartTicks(void)
{
/* Set first ticks value */
#ifdef USE_GETTICKCOUNT
start = GetTickCount();
#else
#if 0 /* Apparently there are problems with QPC on Win2K */
if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE) {
hires_timer_available = TRUE;
QueryPerformanceCounter(&hires_start_ticks);
} else
#endif
{
hires_timer_available = FALSE;
timeBeginPeriod(1); /* use 1 ms timer precision */
start = timeGetTime();
}
#endif
}
Uint32
SDL_GetTicks(void)
{
DWORD now, ticks;
#ifndef USE_GETTICKCOUNT
LARGE_INTEGER hires_now;
#endif
#ifdef USE_GETTICKCOUNT
now = GetTickCount();
#else
if (hires_timer_available) {
QueryPerformanceCounter(&hires_now);
hires_now.QuadPart -= hires_start_ticks.QuadPart;
hires_now.QuadPart *= 1000;
hires_now.QuadPart /= hires_ticks_per_second.QuadPart;
return (DWORD) hires_now.QuadPart;
} else {
now = timeGetTime();
}
#endif
if (now < start) {
ticks = (TIME_WRAP_VALUE - start) + now;
} else {
ticks = (now - start);
}
return (ticks);
}
void
SDL_Delay(Uint32 ms)
{
Sleep(ms);
}
#endif /* SDL_TIMER_WINDOWS */
/* vi: set ts=4 sw=4 expandtab: */