pa_win_ds.c

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        /* Check for underflow */
        if( dsw->dsw_OutputUnderflows != previousUnderflowCount )
            stream->callbackFlags |= paOutputUnderflow;
    }

    if( (numInFramesReady > 0) && (numOutFramesReady > 0) )
    {
        framesToXfer = (numOutFramesReady < numInFramesReady) ? numOutFramesReady : numInFramesReady;
    }

    if( framesToXfer > 0 )
    {

        PaUtil_BeginCpuLoadMeasurement( &stream->cpuLoadMeasurer );

    /* The outputBufferDacTime parameter should indicates the time at which
        the first sample of the output buffer is heard at the DACs. */
        timeInfo.currentTime = PaUtil_GetTime();
        timeInfo.outputBufferDacTime = timeInfo.currentTime + outputLatency;


        PaUtil_BeginBufferProcessing( &stream->bufferProcessor, &timeInfo, stream->callbackFlags );
        stream->callbackFlags = 0;
        
    /* Input */
        if( stream->bufferProcessor.inputChannelCount > 0 )
        {
            bytesToXfer = framesToXfer * dsw->dsw_BytesPerInputFrame;
            hresult = IDirectSoundCaptureBuffer_Lock ( dsw->dsw_InputBuffer,
                dsw->dsw_ReadOffset, bytesToXfer,
                (void **) &lpInBuf1, &dwInSize1,
                (void **) &lpInBuf2, &dwInSize2, 0);
            if (hresult != DS_OK)
            {
                ERR_RPT(("DirectSound IDirectSoundCaptureBuffer_Lock failed, hresult = 0x%x\n",hresult));
                result = paUnanticipatedHostError;
                PA_DS_SET_LAST_DIRECTSOUND_ERROR( hresult );
                goto error2;
            }

            numFrames = dwInSize1 / dsw->dsw_BytesPerInputFrame;
            PaUtil_SetInputFrameCount( &stream->bufferProcessor, numFrames );
            PaUtil_SetInterleavedInputChannels( &stream->bufferProcessor, 0, lpInBuf1, 0 );
        /* Is input split into two regions. */
            if( dwInSize2 > 0 )
            {
                numFrames = dwInSize2 / dsw->dsw_BytesPerInputFrame;
                PaUtil_Set2ndInputFrameCount( &stream->bufferProcessor, numFrames );
                PaUtil_Set2ndInterleavedInputChannels( &stream->bufferProcessor, 0, lpInBuf2, 0 );
            }
        }

    /* Output */
        if( stream->bufferProcessor.outputChannelCount > 0 )
        {
            bytesToXfer = framesToXfer * dsw->dsw_BytesPerOutputFrame;
            hresult = IDirectSoundBuffer_Lock ( dsw->dsw_OutputBuffer,
                dsw->dsw_WriteOffset, bytesToXfer,
                (void **) &lpOutBuf1, &dwOutSize1,
                (void **) &lpOutBuf2, &dwOutSize2, 0);
            if (hresult != DS_OK)
            {
                ERR_RPT(("DirectSound IDirectSoundBuffer_Lock failed, hresult = 0x%x\n",hresult));
                result = paUnanticipatedHostError;
                PA_DS_SET_LAST_DIRECTSOUND_ERROR( hresult );
                goto error1;
            }

            numFrames = dwOutSize1 / dsw->dsw_BytesPerOutputFrame;
            PaUtil_SetOutputFrameCount( &stream->bufferProcessor, numFrames );
            PaUtil_SetInterleavedOutputChannels( &stream->bufferProcessor, 0, lpOutBuf1, 0 );

        /* Is output split into two regions. */
            if( dwOutSize2 > 0 )
            {
                numFrames = dwOutSize2 / dsw->dsw_BytesPerOutputFrame;
                PaUtil_Set2ndOutputFrameCount( &stream->bufferProcessor, numFrames );
                PaUtil_Set2ndInterleavedOutputChannels( &stream->bufferProcessor, 0, lpOutBuf2, 0 );
            }
        }

        result = paContinue;
        numFrames = PaUtil_EndBufferProcessing( &stream->bufferProcessor, &result );
        stream->framesWritten += numFrames;
        
        if( stream->bufferProcessor.outputChannelCount > 0 )
        {
        /* FIXME: an underflow could happen here */

        /* Update our buffer offset and unlock sound buffer */
            bytesProcessed = numFrames * dsw->dsw_BytesPerOutputFrame;
            dsw->dsw_WriteOffset = (dsw->dsw_WriteOffset + bytesProcessed) % dsw->dsw_OutputSize;
            IDirectSoundBuffer_Unlock( dsw->dsw_OutputBuffer, lpOutBuf1, dwOutSize1, lpOutBuf2, dwOutSize2);
            dsw->dsw_FramesWritten += numFrames;
        }

error1:
        if( stream->bufferProcessor.inputChannelCount > 0 )
        {
        /* FIXME: an overflow could happen here */

        /* Update our buffer offset and unlock sound buffer */
            bytesProcessed = numFrames * dsw->dsw_BytesPerInputFrame;
            dsw->dsw_ReadOffset = (dsw->dsw_ReadOffset + bytesProcessed) % dsw->dsw_InputSize;
            IDirectSoundCaptureBuffer_Unlock( dsw->dsw_InputBuffer, lpInBuf1, dwInSize1, lpInBuf2, dwInSize2);
        }
error2:

        PaUtil_EndCpuLoadMeasurement( &stream->cpuLoadMeasurer, numFrames );

    }
    
    return result;
}
/*******************************************************************/
static void CALLBACK Pa_TimerCallback(UINT uID, UINT uMsg, DWORD dwUser, DWORD dw1, DWORD dw2)
{
    PaWinDsStream *stream;

    /* suppress unused variable warnings */
    (void) uID;
    (void) uMsg;
    (void) dw1;
    (void) dw2;
    
    stream = (PaWinDsStream *) dwUser;
    if( stream == NULL ) return;

    if( stream->isActive )
    {
        if( stream->abortProcessing )
        {
            stream->isActive = 0;
        }
        else if( stream->stopProcessing )
        {
            DSoundWrapper   *dsw = &stream->directSoundWrapper;
            if( stream->bufferProcessor.outputChannelCount > 0 )
            {
                DSW_ZeroEmptySpace( dsw );
                /* clear isActive when all sound played */
                if( dsw->dsw_FramesPlayed >= stream->framesWritten )
                {
                    stream->isActive = 0;
                }
            }
            else
            {
                stream->isActive = 0;
            }
        }
        else
        {
            if( Pa_TimeSlice( stream ) != 0)  /* Call time slice independant of timing method. */
            {
                /* FIXME implement handling of paComplete and paAbort if possible */
                stream->stopProcessing = 1;
            }
        }

        if( !stream->isActive ){
            if( stream->streamRepresentation.streamFinishedCallback != 0 )
                stream->streamRepresentation.streamFinishedCallback( stream->streamRepresentation.userData );
        }
    }
}

/***********************************************************************************
    When CloseStream() is called, the multi-api layer ensures that
    the stream has already been stopped or aborted.
*/
static PaError CloseStream( PaStream* s )
{
    PaError result = paNoError;
    PaWinDsStream *stream = (PaWinDsStream*)s;

    DSW_Term( &stream->directSoundWrapper );

    PaUtil_TerminateBufferProcessor( &stream->bufferProcessor );
    PaUtil_TerminateStreamRepresentation( &stream->streamRepresentation );
    PaUtil_FreeMemory( stream );

    return result;
}

/***********************************************************************************/
static PaError StartStream( PaStream *s )
{
    PaError          result = paNoError;
    PaWinDsStream   *stream = (PaWinDsStream*)s;
    HRESULT          hr;

    PaUtil_ResetBufferProcessor( &stream->bufferProcessor );
    
    if( stream->bufferProcessor.inputChannelCount > 0 )
    {
        hr = DSW_StartInput( &stream->directSoundWrapper );
        DBUG(("StartStream: DSW_StartInput returned = 0x%X.\n", hr));
        if( hr != DS_OK )
        {
            result = paUnanticipatedHostError;
            PA_DS_SET_LAST_DIRECTSOUND_ERROR( hr );
            goto error;
        }
    }

    stream->framesWritten = 0;
    stream->callbackFlags = 0;

    stream->abortProcessing = 0;
    stream->stopProcessing = 0;
    stream->isActive = 1;

    if( stream->bufferProcessor.outputChannelCount > 0 )
    {
        /* Give user callback a chance to pre-fill buffer. REVIEW - i thought we weren't pre-filling, rb. */
        result = Pa_TimeSlice( stream );
        if( result != paNoError ) return result; // FIXME - what if finished?

        hr = DSW_StartOutput( &stream->directSoundWrapper );
        DBUG(("PaHost_StartOutput: DSW_StartOutput returned = 0x%X.\n", hr));
        if( hr != DS_OK )
        {
            result = paUnanticipatedHostError;
            PA_DS_SET_LAST_DIRECTSOUND_ERROR( hr );
            goto error;
        }
    }


    /* Create timer that will wake us up so we can fill the DSound buffer. */
    {
        int resolution;
        int framesPerWakeup = stream->framesPerDSBuffer / 4;
        int msecPerWakeup = MSEC_PER_SECOND * framesPerWakeup / (int) stream->streamRepresentation.streamInfo.sampleRate;
        if( msecPerWakeup < 10 ) msecPerWakeup = 10;
        else if( msecPerWakeup > 100 ) msecPerWakeup = 100;
        resolution = msecPerWakeup/4;
        stream->timerID = timeSetEvent( msecPerWakeup, resolution, (LPTIMECALLBACK) Pa_TimerCallback,
                                             (DWORD) stream, TIME_PERIODIC );
    }
    if( stream->timerID == 0 )
    {
        stream->isActive = 0;
        result = paUnanticipatedHostError;
        PA_DS_SET_LAST_DIRECTSOUND_ERROR( hr );
        goto error;
    }

    stream->isStarted = TRUE;

error:
    return result;
}


/***********************************************************************************/
static PaError StopStream( PaStream *s )
{
    PaError result = paNoError;
    PaWinDsStream *stream = (PaWinDsStream*)s;
    HRESULT          hr;
    int timeoutMsec;

    stream->stopProcessing = 1;
    /* Set timeout at 20% beyond maximum time we might wait. */
    timeoutMsec = (int) (1200.0 * stream->framesPerDSBuffer / stream->streamRepresentation.streamInfo.sampleRate);
    while( stream->isActive && (timeoutMsec > 0)  )
    {
        Sleep(10);
        timeoutMsec -= 10;
    }
    if( stream->timerID != 0 )
    {
        timeKillEvent(stream->timerID);  /* Stop callback timer. */
        stream->timerID = 0;
    }


    if( stream->bufferProcessor.outputChannelCount > 0 )
    {
        hr = DSW_StopOutput( &stream->directSoundWrapper );
    }

    if( stream->bufferProcessor.inputChannelCount > 0 )
    {
        hr = DSW_StopInput( &stream->directSoundWrapper );
    }

    stream->isStarted = FALSE;

    return result;
}


/***********************************************************************************/
static PaError AbortStream( PaStream *s )
{
    PaWinDsStream *stream = (PaWinDsStream*)s;

    stream->abortProcessing = 1;
    return StopStream( s );
}


/***********************************************************************************/
static PaError IsStreamStopped( PaStream *s )
{
    PaWinDsStream *stream = (PaWinDsStream*)s;

    return !stream->isStarted;
}


/***********************************************************************************/
static PaError IsStreamActive( PaStream *s )
{
    PaWinDsStream *stream = (PaWinDsStream*)s;

    return stream->isActive;
}

/***********************************************************************************/
static PaTime GetStreamTime( PaStream *s )
{
    /* suppress unused variable warnings */
    (void) s;

    
/*
    new behavior for GetStreamTime is to return a stream based seconds clock
    used for the outTime parameter to the callback.
    FIXME: delete this comment when the other unnecessary related code has
    been cleaned from this file.

    PaWinDsStream *stream = (PaWinDsStream*)s;
    DSoundWrapper   *dsw;
    dsw = &stream->directSoundWrapper;
    return dsw->dsw_FramesPlayed;
*/
    return PaUtil_GetTime();
}


/***********************************************************************************/
static double GetStreamCpuLoad( PaStream* s )
{
    PaWinDsStream *stream = (PaWinDsStream*)s;

    return PaUtil_GetCpuLoad( &stream->cpuLoadMeasurer );
}



/***********************************************************************************
    As separate stream interfaces are used for blocking and callback
    streams, the following functions can be guaranteed to only be called
    for blocking streams.
*/

static PaError ReadStream( PaStream* s,
                           void *buffer,
                           unsigned long frames )
{
    PaWinDsStream *stream = (PaWinDsStream*)s;

    /* suppress unused variable warnings */
    (void) buffer;
    (void) frames;
    (void) stream;

    /* IMPLEMENT ME, see portaudio.h for required behavior*/

    return paNoError;
}


/***********************************************************************************/
static PaError WriteStream( PaStream* s,
                            const void *buffer,
                            unsigned long frames )
{
    PaWinDsStream *stream = (PaWinDsStream*)s;

    /* suppress unused variable warnings */
    (void) buffer;
    (void) frames;
    (void) stream;

    /* IMPLEMENT ME, see portaudio.h for required behavior*/

    return paNoError;
}


/***********************************************************************************/
static signed long GetStreamReadAvailable( PaStream* s )
{
    PaWinDsStream *stream = (PaWinDsStream*)s;

    /* suppress unused variable warnings */
    (void) stream;

    /* IMPLEMENT ME, see portaudio.h for required behavior*/

    return 0;
}


/***********************************************************************************/
static signed long GetStreamWriteAvailable( PaStream* s )
{
    PaWinDsStream *stream = (PaWinDsStream*)s;

    /* suppress unused variable warnings */
    (void) stream;
    
    /* IMPLEMENT ME, see portaudio.h for required behavior*/

    return 0;
}