kc3-lang/SDL/src/timer/windows/SDL_systimer.c

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• Hash : 3dcb451f
  Author :
  Date : 2014-04-09T21:29:19
  

  Added a README file regarding WinRT support To note, this file is currently formatted with CRLF line endings, rather than LF, to allow the file to be viewed with Notepad.

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• src/timer/windows/SDL_systimer.c

• /*
    Simple DirectMedia Layer
    Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
  
    This software is provided 'as-is', without any express or implied
    warranty.  In no event will the authors be held liable for any damages
    arising from the use of this software.
  
    Permission is granted to anyone to use this software for any purpose,
    including commercial applications, and to alter it and redistribute it
    freely, subject to the following restrictions:
  
    1. The origin of this software must not be misrepresented; you must not
       claim that you wrote the original software. If you use this software
       in a product, an acknowledgment in the product documentation would be
       appreciated but is not required.
    2. Altered source versions must be plainly marked as such, and must not be
       misrepresented as being the original software.
    3. This notice may not be removed or altered from any source distribution.
  */
  #include "../../SDL_internal.h"
  
  #ifdef SDL_TIMER_WINDOWS
  
  #include "../../core/windows/SDL_windows.h"
  #include <mmsystem.h>
  
  #include "SDL_timer.h"
  #include "SDL_hints.h"
  
  
  /* The first (low-resolution) ticks value of the application */
  static DWORD start;
  static BOOL ticks_started = FALSE; 
  
  #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;
  
  #ifndef __WINRT__
  static void
  timeSetPeriod(UINT uPeriod)
  {
      static UINT timer_period = 0;
  
      if (uPeriod != timer_period) {
          if (timer_period) {
              timeEndPeriod(timer_period);
          }
  
          timer_period = uPeriod;
  
          if (timer_period) {
              timeBeginPeriod(timer_period);
          }
      }
  }
  
  static void
  SDL_TimerResolutionChanged(void *userdata, const char *name, const char *oldValue, const char *hint)
  {
      UINT uPeriod;
  
      /* Unless the hint says otherwise, let's have good sleep precision */
      if (hint && *hint) {
          uPeriod = SDL_atoi(hint);
      } else {
          uPeriod = 1;
      }
      if (uPeriod || oldValue != hint) {
          timeSetPeriod(uPeriod);
      }
  }
  #endif /* ifndef __WINRT__ */
  
  #endif /* !USE_GETTICKCOUNT */
  
  void
  SDL_TicksInit(void)
  {
      if (ticks_started) {
          return;
      }
      ticks_started = SDL_TRUE;
  
      /* Set first ticks value */
  #ifdef USE_GETTICKCOUNT
      start = GetTickCount();
  #else
      /* QueryPerformanceCounter has had problems in the past, but lots of games
         use it, so we'll rely on it here.
       */
      if (QueryPerformanceFrequency(&hires_ticks_per_second) == TRUE) {
          hires_timer_available = TRUE;
          QueryPerformanceCounter(&hires_start_ticks);
      } else {
          hires_timer_available = FALSE;
  #ifdef __WINRT__
          start = 0;            /* the timer failed to start! */
  #else
          timeSetPeriod(1);     /* use 1 ms timer precision */
          start = timeGetTime();
  
          SDL_AddHintCallback(SDL_HINT_TIMER_RESOLUTION,
                              SDL_TimerResolutionChanged, NULL);
  #endif /* __WINRT__ */
      }
  #endif /* USE_GETTICKCOUNT */
  }
  
  void
  SDL_TicksQuit(void)
  {
  #ifndef USE_GETTICKCOUNT
      if (!hires_timer_available) {
  #ifndef __WINRT__
          SDL_DelHintCallback(SDL_HINT_TIMER_RESOLUTION,
                              SDL_TimerResolutionChanged, NULL);
  
          timeSetPeriod(0);
  #endif /* __WINRT__ */
      }
  #endif /* USE_GETTICKCOUNT */
  
      ticks_started = SDL_FALSE;
  }
  
  Uint32
  SDL_GetTicks(void)
  {
      DWORD now;
  #ifndef USE_GETTICKCOUNT
      LARGE_INTEGER hires_now;
  #endif
  
      if (!ticks_started) {
          SDL_TicksInit();
      }
  
  #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 {
  #ifdef __WINRT__
          now = 0;
  #else
          now = timeGetTime();
  #endif /* __WINRT__ */
      }
  #endif
  
      return (now - start);
  }
  
  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;
  }
  
  #ifdef __WINRT__
  static void
  Sleep(DWORD timeout)
  {
      static HANDLE mutex = 0;
      if ( ! mutex )
      {
          mutex = CreateEventEx(0, 0, 0, EVENT_ALL_ACCESS);
      }
      WaitForSingleObjectEx(mutex, timeout, FALSE);
  }
  #endif
  
  void
  SDL_Delay(Uint32 ms)
  {
      Sleep(ms);
  }
  
  #endif /* SDL_TIMER_WINDOWS */
  
  /* vi: set ts=4 sw=4 expandtab: */
  

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