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SDL_systimer.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2011 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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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
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Lesser General Public License for more details.
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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
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Sam Lantinga
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slouken@libsdl.org
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*/
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#include "SDL_config.h"
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#ifdef SDL_TIMER_WINDOWS
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#include "../../core/windows/SDL_windows.h"
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#include <mmsystem.h>
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#include "SDL_timer.h"
#ifdef _WIN32_WCE
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#error This is WinCE. Please use src/timer/wince/SDL_systimer.c instead.
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#endif
#define TIME_WRAP_VALUE (~(DWORD)0)
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/* The first (low-resolution) ticks value of the application */
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static DWORD start;
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#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
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void
SDL_StartTicks(void)
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/* Set first ticks value */
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#ifdef USE_GETTICKCOUNT
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start = GetTickCount();
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#else
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#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
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{
hires_timer_available = FALSE;
timeBeginPeriod(1); /* use 1 ms timer precision */
start = timeGetTime();
}
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#endif
}
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Uint32
SDL_GetTicks(void)
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DWORD now, ticks;
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#ifndef USE_GETTICKCOUNT
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LARGE_INTEGER hires_now;
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#ifdef USE_GETTICKCOUNT
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now = GetTickCount();
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#else
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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();
}
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#endif
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if (now < start) {
ticks = (TIME_WRAP_VALUE - start) + now;
} else {
ticks = (now - start);
}
return (ticks);
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}
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Uint64
SDL_GetPerformanceCounter(void)
{
LARGE_INTEGER counter;
if (!QueryPerformanceCounter(&counter)) {
return SDL_GetTicks();
}
return counter.QuadPart;
}
Uint64
SDL_GetPerformanceFrequency(void)
{
LARGE_INTEGER frequency;
if (!QueryPerformanceFrequency(&frequency)) {
return 1000;
}
return frequency.QuadPart;
}
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void
SDL_Delay(Uint32 ms)
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{
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}
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#endif /* SDL_TIMER_WINDOWS */
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/* vi: set ts=4 sw=4 expandtab: */