/project/jni/sdl-1.3/src/timer/windows/SDL_systimer.c

  1/*
  2  Simple DirectMedia Layer
  3  Copyright (C) 1997-2012 Sam Lantinga <slouken@libsdl.org>
  4
  5  This software is provided 'as-is', without any express or implied
  6  warranty.  In no event will the authors be held liable for any damages
  7  arising from the use of this software.
  8
  9  Permission is granted to anyone to use this software for any purpose,
 10  including commercial applications, and to alter it and redistribute it
 11  freely, subject to the following restrictions:
 12
 13  1. The origin of this software must not be misrepresented; you must not
 14     claim that you wrote the original software. If you use this software
 15     in a product, an acknowledgment in the product documentation would be
 16     appreciated but is not required.
 17  2. Altered source versions must be plainly marked as such, and must not be
 18     misrepresented as being the original software.
 19  3. This notice may not be removed or altered from any source distribution.
 20*/
 21#include "SDL_config.h"
 22
 23#ifdef SDL_TIMER_WINDOWS
 24
 25#include "../../core/windows/SDL_windows.h"
 26#include <mmsystem.h>
 27
 28#include "SDL_timer.h"
 29
 30#ifdef _WIN32_WCE
 31#error This is WinCE. Please use src/timer/wince/SDL_systimer.c instead.
 32#endif
 33
 34#define TIME_WRAP_VALUE	(~(DWORD)0)
 35
 36/* The first (low-resolution) ticks value of the application */
 37static DWORD start;
 38
 39#ifndef USE_GETTICKCOUNT
 40/* Store if a high-resolution performance counter exists on the system */
 41static BOOL hires_timer_available;
 42/* The first high-resolution ticks value of the application */
 43static LARGE_INTEGER hires_start_ticks;
 44/* The number of ticks per second of the high-resolution performance counter */
 45static LARGE_INTEGER hires_ticks_per_second;
 46#endif
 47
 48void
 49SDL_StartTicks(void)
 50{
 51    /* Set first ticks value */
 52#ifdef USE_GETTICKCOUNT
 53    start = GetTickCount();
 54#else
 55#if 0                           /* Apparently there are problems with QPC on Win2K */
 56    if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE) {
 57        hires_timer_available = TRUE;
 58        QueryPerformanceCounter(&hires_start_ticks);
 59    } else
 60#endif
 61    {
 62        hires_timer_available = FALSE;
 63        timeBeginPeriod(1);     /* use 1 ms timer precision */
 64        start = timeGetTime();
 65    }
 66#endif
 67}
 68
 69Uint32
 70SDL_GetTicks(void)
 71{
 72    DWORD now, ticks;
 73#ifndef USE_GETTICKCOUNT
 74    LARGE_INTEGER hires_now;
 75#endif
 76
 77#ifdef USE_GETTICKCOUNT
 78    now = GetTickCount();
 79#else
 80    if (hires_timer_available) {
 81        QueryPerformanceCounter(&hires_now);
 82
 83        hires_now.QuadPart -= hires_start_ticks.QuadPart;
 84        hires_now.QuadPart *= 1000;
 85        hires_now.QuadPart /= hires_ticks_per_second.QuadPart;
 86
 87        return (DWORD) hires_now.QuadPart;
 88    } else {
 89        now = timeGetTime();
 90    }
 91#endif
 92
 93    if (now < start) {
 94        ticks = (TIME_WRAP_VALUE - start) + now;
 95    } else {
 96        ticks = (now - start);
 97    }
 98    return (ticks);
 99}
100
101Uint64
102SDL_GetPerformanceCounter(void)
103{
104    LARGE_INTEGER counter;
105
106    if (!QueryPerformanceCounter(&counter)) {
107        return SDL_GetTicks();
108    }
109    return counter.QuadPart;
110}
111
112Uint64
113SDL_GetPerformanceFrequency(void)
114{
115    LARGE_INTEGER frequency;
116
117    if (!QueryPerformanceFrequency(&frequency)) {
118        return 1000;
119    }
120    return frequency.QuadPart;
121}
122
123void
124SDL_Delay(Uint32 ms)
125{
126    Sleep(ms);
127}
128
129#endif /* SDL_TIMER_WINDOWS */
130
131/* vi: set ts=4 sw=4 expandtab: */