[PATCH 1/4] winmm: Use microsecond unit in MIDI stream position variable to simplify the code.

[Andrew Eikum]

Signed-off-by: Andrew Eikum <aeikum at codeweavers.com>

On Wed, Jul 11, 2018 at 10:33:19PM +0900, Akihiro Sagawa wrote:
> 
> Andrew, thanks for reviewing.
> 
> Since 32-bit variable overflows after approximately 70 minutes,
> we use 64-bit variable for this purpose. `remainder' member is removed.
> 
> Signed-off-by: Akihiro Sagawa <sagawa.aki at gmail.com>
> ---
>  dlls/winmm/winmm.c | 20 +++++++-------------
>  1 file changed, 7 insertions(+), 13 deletions(-)
> 

> diff --git a/dlls/winmm/winmm.c b/dlls/winmm/winmm.c
> index 0328721..4b8d4de 100644
> --- a/dlls/winmm/winmm.c
> +++ b/dlls/winmm/winmm.c
> @@ -915,13 +915,12 @@ typedef struct WINE_MIDIStream {
>      CRITICAL_SECTION		lock;
>      DWORD			dwTempo;
>      DWORD			dwTimeDiv;
> -    DWORD			dwPositionMS;
> +    ULONGLONG			position_usec;
>      DWORD			dwPulses;
>      DWORD			dwStartTicks;
>      DWORD			dwElapsedMS;
>      WORD			wFlags;
>      WORD			status;
> -    WORD			remainder;
>      HANDLE			hEvent;
>      LPMIDIHDR			lpMidiHdr;
>  } WINE_MIDIStream;
> @@ -1008,8 +1007,7 @@ static	BOOL	MMSYSTEM_MidiStream_MessageHandler(WINE_MIDIStream* lpMidiStrm, LPWI
>              lpMidiStrm->status = MSM_STATUS_STOPPED;
>              lpMidiStrm->dwPulses = 0;
>              lpMidiStrm->dwElapsedMS = 0;
> -            lpMidiStrm->dwPositionMS = 0;
> -            lpMidiStrm->remainder = 0;
> +            lpMidiStrm->position_usec = 0;
>              LeaveCriticalSection(&lpMidiStrm->lock);
>              /* this is not quite what MS doc says... */
>              midiOutReset(lpMidiStrm->hDevice);
> @@ -1181,15 +1179,12 @@ start_header:
>  
>  	/* do we have to wait ? */
>  	if (me->dwDeltaTime) {
> -	    DWORD delta;
>  	    EnterCriticalSection(&lpMidiStrm->lock);
> -	    delta = lpMidiStrm->remainder + MMSYSTEM_MidiStream_Convert(lpMidiStrm, me->dwDeltaTime);
> -	    lpMidiStrm->dwPositionMS += delta / 1000;
> -	    lpMidiStrm->remainder = delta % 1000;
> +	    lpMidiStrm->position_usec += MMSYSTEM_MidiStream_Convert(lpMidiStrm, me->dwDeltaTime);
>  	    lpMidiStrm->dwPulses += me->dwDeltaTime;
>  	    LeaveCriticalSection(&lpMidiStrm->lock);
>  
> -	    dwToGo = lpMidiStrm->dwStartTicks + lpMidiStrm->dwPositionMS;
> +	    dwToGo = lpMidiStrm->dwStartTicks + lpMidiStrm->position_usec / 1000;
>  
>  	    TRACE("%u/%u/%u\n", dwToGo, GetTickCount(), me->dwDeltaTime);
>  	    while (dwToGo - (dwCurrTC = GetTickCount()) <= MAXLONG) {
> @@ -1204,7 +1199,7 @@ start_header:
>  			}
>  		    }
>  		    /* reset dwToGo because dwStartTicks might be updated */
> -		    dwToGo = lpMidiStrm->dwStartTicks + lpMidiStrm->dwPositionMS;
> +		    dwToGo = lpMidiStrm->dwStartTicks + lpMidiStrm->position_usec / 1000;
>  		} else {
>  		    /* timeout, so me->dwDeltaTime is elapsed, can break the while loop */
>  		    break;
> @@ -1334,10 +1329,9 @@ MMRESULT WINAPI midiStreamOpen(HMIDISTRM* lphMidiStrm, LPUINT lpuDeviceID,
>      if (!lpMidiStrm)
>  	return MMSYSERR_NOMEM;
>  
> -    lpMidiStrm->dwTempo = 500000;  /* micro seconds per quarter note, i.e. 120 BPM */
> +    lpMidiStrm->dwTempo = 500000;  /* microseconds per quarter note, i.e. 120 BPM */
>      lpMidiStrm->dwTimeDiv = 24;    /* ticks per quarter note */
> -    lpMidiStrm->dwPositionMS = 0;
> -    lpMidiStrm->remainder = 0;
> +    lpMidiStrm->position_usec = 0;
>      lpMidiStrm->status = MSM_STATUS_PAUSED;
>      lpMidiStrm->dwElapsedMS = 0;
>  

>