/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2020 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"

#if SDL_TIMER_OS2

#include "SDL_timer.h"
#include "../../core/os2/SDL_os2.h"

#define INCL_DOSERRORS
#define INCL_DOSMISC
#define INCL_DOSPROFILE
#define INCL_DOSSEMAPHORES
#define INCL_DOSDATETIME
#define INCL_DOSPROCESS
#define INCL_DOSEXCEPTIONS
#include <os2.h>

// No need to switch priorities in SDL_Delay() for OS/2 versions > Warp3 fp 42.
//#define _SWITCH_PRIORITY

typedef unsigned long long       ULLONG;

static ULONG           ulTmrFreq = 0;
static ULLONG          ullTmrStart;

void
SDL_TicksInit(void)
{
  ULONG      ulRC;

  ulRC = DosTmrQueryFreq( &ulTmrFreq );
  if ( ulRC != NO_ERROR )
  {
    debug( "DosTmrQueryFreq() failed, rc = %u", ulRC );
  }
  else
  {
    ulRC = DosTmrQueryTime( (PQWORD)&ullTmrStart );
    if ( ulRC == NO_ERROR )
      return;

    debug( "DosTmrQueryTime() failed, rc = %u", ulRC );
  }

  ulTmrFreq = 0; // Error - use DosQuerySysInfo() for timer.

  DosQuerySysInfo( QSV_MS_COUNT, QSV_MS_COUNT, (PULONG)&ullTmrStart,
                   sizeof(ULONG) );
}

void
SDL_TicksQuit(void)
{
}

Uint32
SDL_GetTicks(void)
{
  ULONG      ulResult;
  ULLONG     ullTmrNow;

  if ( ulTmrFreq == 0 )
    // Was not initialized.
    SDL_TicksInit();

  if ( ulTmrFreq != 0 )
  {
    DosTmrQueryTime( (PQWORD)&ullTmrNow );
    ulResult = ( ullTmrNow - ullTmrStart ) * 1000 / ulTmrFreq;
  }
  else
  {
    DosQuerySysInfo( QSV_MS_COUNT, QSV_MS_COUNT, (PULONG)&ullTmrNow,
                     sizeof(ULONG) );
    ulResult = (ULONG)ullTmrNow - (ULONG)ullTmrStart;
  }

  return ulResult;
}

Uint64
SDL_GetPerformanceCounter(void)
{
  QWORD      qwTmrNow;

  if ( ( ulTmrFreq == 0 ) || ( DosTmrQueryTime( &qwTmrNow ) != NO_ERROR ) )
    return SDL_GetTicks();

  return *((Uint64 *)&qwTmrNow);
}

Uint64
SDL_GetPerformanceFrequency(void)
{
  return ulTmrFreq == 0 ? 1000 : (Uint64)ulTmrFreq;
}

void
SDL_Delay(Uint32 ms)
{
  HTIMER     hTimer = NULLHANDLE;
  ULONG      ulRC;
#ifdef _SWITCH_PRIORITY
  PPIB       pib;
  PTIB       tib;
  BOOL       fSetPriority = ms < 50;
  ULONG      ulSavePriority;
  ULONG      ulNesting;
#endif
  HEV        hevTimer;

  if ( ms == 0 )
  {
    DosSleep( 0 );
    return;
  }

  ulRC = DosCreateEventSem( NULL, &hevTimer, DC_SEM_SHARED, FALSE );
  if ( ulRC != NO_ERROR )
  {
    debug( "DosAsyncTimer() failed, rc = %u", ulRC );
    DosSleep( ms );
    return;
  }

#ifdef _SWITCH_PRIORITY
  if ( fSetPriority )
  {
    if ( DosGetInfoBlocks( &tib, &pib ) != NO_ERROR )
      fSetPriority = FALSE;
    else
    {
      ulSavePriority = tib->tib_ptib2->tib2_ulpri;
      if ( ( (ulSavePriority & 0xFF00) == 0x0300 ) ||  // already have high pr.
           ( DosEnterMustComplete( &ulNesting ) != NO_ERROR ) )
        fSetPriority = FALSE;
      else
        DosSetPriority( PRTYS_THREAD, PRTYC_TIMECRITICAL, 0, 0 );
    }
  }
#endif

  DosResetEventSem( hevTimer, &ulRC );
  ulRC = DosAsyncTimer( ms, (HSEM)hevTimer, &hTimer );

#ifdef _SWITCH_PRIORITY
  if ( fSetPriority )
  {
    if ( DosSetPriority( PRTYS_THREAD, (ulSavePriority >> 8) & 0xFF, 0, 0 ) ==
           NO_ERROR )
      DosSetPriority( PRTYS_THREAD, 0, ulSavePriority & 0xFF, 0 );

    DosExitMustComplete( &ulNesting );
  }
#endif

  if ( ulRC != NO_ERROR )
    debug( "DosAsyncTimer() failed, rc = %u", ulRC );
  else
    DosWaitEventSem( hevTimer, SEM_INDEFINITE_WAIT );

  if ( ulRC != NO_ERROR )
    DosSleep( ms );

  DosCloseEventSem( hevTimer );
}

#endif /* SDL_TIMER_OS2 */

/* vi: set ts=4 sw=4 expandtab: */