Ticket #54: pa_win_ds.c

/*
 * $Id: pa_win_ds.c 1116 2006-09-06 15:47:03Z rossb $
 * Portable Audio I/O Library DirectSound implementation
 *
 * Authors: Phil Burk, Robert Marsanyi & Ross Bencina
 * Based on the Open Source API proposed by Ross Bencina
 * Copyright (c) 1999-2006 Ross Bencina, Phil Burk, Robert Marsanyi
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * The text above constitutes the entire PortAudio license; however, 
 * the PortAudio community also makes the following non-binding requests:
 *
 * Any person wishing to distribute modifications to the Software is
 * requested to send the modifications to the original developer so that
 * they can be incorporated into the canonical version. It is also 
 * requested that these non-binding requests be included along with the 
 * license above.
 */

/** @file
 @ingroup hostaip_src

    @todo implement paInputOverflow callback status flag
    
    @todo implement paNeverDropInput.

    @todo implement host api specific extension to set i/o buffer sizes in frames

    @todo implement initialisation of PaDeviceInfo default*Latency fields (currently set to 0.)

    @todo implement ReadStream, WriteStream, GetStreamReadAvailable, GetStreamWriteAvailable

    @todo audit handling of DirectSound result codes - in many cases we could convert a HRESULT into
        a native portaudio error code. Standard DirectSound result codes are documented at msdn.

    @todo implement IsFormatSupported

    @todo check that CoInitialize() CoUninitialize() are always correctly
        paired, even in error cases.

    @todo call PaUtil_SetLastHostErrorInfo with a specific error string (currently just "DSound error").

    @todo make sure all buffers have been played before stopping the stream
        when the stream callback returns paComplete

    old TODOs from phil, need to work out if these have been done:
        O- fix "patest_stop.c"
*/

#include <stdio.h>
#include <string.h> /* strlen() */

// Include the KS headers for WAVEFORMATEXTENSIBLE
#define _INC_MMREG // This is required for certain guids in ksmedia
#include <windows.h>
#include <ks.h>
#include <ksmedia.h>

#include "pa_util.h"
#include "pa_allocation.h"
#include "pa_hostapi.h"
#include "pa_stream.h"
#include "pa_cpuload.h"
#include "pa_process.h"

#include "pa_win_ds_dynlink.h"

#if (defined(WIN32) && (defined(_MSC_VER) && (_MSC_VER >= 1200))) /* MSC version 6 and above */
#pragma comment( lib, "dsound.lib" )
#pragma comment( lib, "winmm.lib" )
#endif

/*
 provided in newer platform sdks and x64
 */
#ifndef DWORD_PTR
#define DWORD_PTR DWORD
#endif

/* Define the maximum number of channels to be two.
 * Increasing this number will give you multi-channel capacity at the expense
 * of inaccurate reporting of the number of maximum output channels.
 */
#ifndef PA_DS_MAX_CHANS
#define PA_DS_MAX_CHANS 2
#endif

#define PRINT(x) PA_DEBUG(x);
#define ERR_RPT(x) PRINT(x)
#define DBUG(x)   PRINT(x)
#define DBUGX(x)  PRINT(x)

#define PA_USE_HIGH_LATENCY   (0)
#if PA_USE_HIGH_LATENCY
#define PA_WIN_9X_LATENCY     (500)
#define PA_WIN_NT_LATENCY     (600)
#else
#define PA_WIN_9X_LATENCY     (140)
#define PA_WIN_NT_LATENCY     (280)
#endif

#define PA_WIN_WDM_LATENCY       (120)

#define SECONDS_PER_MSEC      (0.001)
#define MSEC_PER_SECOND       (1000)

/* prototypes for functions declared in this file */

#ifdef __cplusplus
extern "C"
{
#endif /* __cplusplus */

PaError PaWinDs_Initialize( PaUtilHostApiRepresentation **hostApi, PaHostApiIndex index );

#ifdef __cplusplus
}
#endif /* __cplusplus */

static void Terminate( struct PaUtilHostApiRepresentation *hostApi );
static PaError OpenStream( struct PaUtilHostApiRepresentation *hostApi,
                           PaStream** s,
                           const PaStreamParameters *inputParameters,
                           const PaStreamParameters *outputParameters,
                           double sampleRate,
                           unsigned long framesPerBuffer,
                           PaStreamFlags streamFlags,
                           PaStreamCallback *streamCallback,
                           void *userData );
static PaError IsFormatSupported( struct PaUtilHostApiRepresentation *hostApi,
                                  const PaStreamParameters *inputParameters,
                                  const PaStreamParameters *outputParameters,
                                  double sampleRate );
static PaError CloseStream( PaStream* stream );
static PaError StartStream( PaStream *stream );
static PaError StopStream( PaStream *stream );
static PaError AbortStream( PaStream *stream );
static PaError IsStreamStopped( PaStream *s );
static PaError IsStreamActive( PaStream *stream );
static PaTime GetStreamTime( PaStream *stream );
static double GetStreamCpuLoad( PaStream* stream );
static PaError ReadStream( PaStream* stream, void *buffer, unsigned long frames );
static PaError WriteStream( PaStream* stream, const void *buffer, unsigned long frames );
static signed long GetStreamReadAvailable( PaStream* stream );
static signed long GetStreamWriteAvailable( PaStream* stream );


/* FIXME: should convert hr to a string */
#define PA_DS_SET_LAST_DIRECTSOUND_ERROR( hr ) \
    PaUtil_SetLastHostErrorInfo( paDirectSound, hr, "DirectSound error" )

/************************************************* DX Prototypes **********/
static BOOL CALLBACK CollectGUIDsProc(LPGUID lpGUID,
                                     LPCTSTR lpszDesc,
                                     LPCTSTR lpszDrvName,
                                     LPVOID lpContext );

/************************************************************************************/
/********************** Structures **************************************************/
/************************************************************************************/
/* PaWinDsHostApiRepresentation - host api datastructure specific to this implementation */

typedef struct PaWinDsDeviceInfo
{
    GUID                             guid;
    GUID                            *lpGUID;
    double                           sampleRates[3];
} PaWinDsDeviceInfo;

typedef struct
{
    PaUtilHostApiRepresentation inheritedHostApiRep;
    PaUtilStreamInterface    callbackStreamInterface;
    PaUtilStreamInterface    blockingStreamInterface;

    PaUtilAllocationGroup   *allocations;

    /* implementation specific data goes here */
    PaWinDsDeviceInfo       *winDsDeviceInfos;

} PaWinDsHostApiRepresentation;


/* PaWinDsStream - a stream data structure specifically for this implementation */

typedef struct PaWinDsStream
{
    PaUtilStreamRepresentation streamRepresentation;
    PaUtilCpuLoadMeasurer cpuLoadMeasurer;
    PaUtilBufferProcessor bufferProcessor;

/* DirectSound specific data. */

/* Output */
    LPDIRECTSOUND        pDirectSound;
    LPDIRECTSOUNDBUFFER  pDirectSoundOutputBuffer;
    DWORD                outputBufferWriteOffsetBytes;     /* last write position */
    INT                  outputBufferSizeBytes;
    INT                  bytesPerOutputFrame;
    /* Try to detect play buffer underflows. */
    LARGE_INTEGER        perfCounterTicksPerBuffer; /* counter ticks it should take to play a full buffer */
    LARGE_INTEGER        previousPlayTime;
    UINT                 previousPlayCursor;
    UINT                 outputUnderflowCount;
    BOOL                 outputIsRunning;
    /* use double which lets us can play for several thousand years with enough precision */
    double               dsw_framesWritten;
    double               framesPlayed;
/* Input */
    LPDIRECTSOUNDCAPTURE pDirectSoundCapture;
    LPDIRECTSOUNDCAPTUREBUFFER   pDirectSoundInputBuffer;
    INT                  bytesPerInputFrame;
    UINT                 readOffset;      /* last read position */
    UINT                 inputSize;

    
    MMRESULT         timerID;
    int              framesPerDSBuffer;
    double           framesWritten;
    double           secondsPerHostByte; /* Used to optimize latency calculation for outTime */

    PaStreamCallbackFlags callbackFlags;
    
/* FIXME - move all below to PaUtilStreamRepresentation */
    volatile int     isStarted;
    volatile int     isActive;
    volatile int     stopProcessing; /* stop thread once existing buffers have been returned */
    volatile int     abortProcessing; /* stop thread immediately */
} PaWinDsStream;


/************************************************************************************
** Duplicate the input string using the allocations allocator.
** A NULL string is converted to a zero length string.
** If memory cannot be allocated, NULL is returned.
**/
static char *DuplicateDeviceNameString( PaUtilAllocationGroup *allocations, const char* src )
{
    char *result = 0;
    
    if( src != NULL )
    {
        size_t len = strlen(src);
        result = (char*)PaUtil_GroupAllocateMemory( allocations, (long)(len + 1) );
        if( result )
            memcpy( (void *) result, src, len+1 );
    }
    else
    {
        result = (char*)PaUtil_GroupAllocateMemory( allocations, 1 );
        if( result )
            result[0] = '\0';
    }

    return result;
}

/************************************************************************************
** DSDeviceNameAndGUID, DSDeviceNameAndGUIDVector used for collecting preliminary
** information during device enumeration.
*/
typedef struct DSDeviceNameAndGUID{
    char *name; // allocated from parent's allocations, never deleted by this structure
    GUID guid;
    LPGUID lpGUID;
} DSDeviceNameAndGUID;

typedef struct DSDeviceNameAndGUIDVector{
    PaUtilAllocationGroup *allocations;
    PaError enumerationError;

    int count;
    int free;
    DSDeviceNameAndGUID *items; // Allocated using LocalAlloc()
} DSDeviceNameAndGUIDVector;

static PaError InitializeDSDeviceNameAndGUIDVector(
        DSDeviceNameAndGUIDVector *guidVector, PaUtilAllocationGroup *allocations )
{
    PaError result = paNoError;

    guidVector->allocations = allocations;
    guidVector->enumerationError = paNoError;

    guidVector->count = 0;
    guidVector->free = 8;
    guidVector->items = (DSDeviceNameAndGUID*)LocalAlloc( LMEM_FIXED, sizeof(DSDeviceNameAndGUID) * guidVector->free );
    if( guidVector->items == NULL )
        result = paInsufficientMemory;
    
    return result;
}

static PaError ExpandDSDeviceNameAndGUIDVector( DSDeviceNameAndGUIDVector *guidVector )
{
    PaError result = paNoError;
    DSDeviceNameAndGUID *newItems;
    int i;
    
    /* double size of vector */
    int size = guidVector->count + guidVector->free;
    guidVector->free += size;

    newItems = (DSDeviceNameAndGUID*)LocalAlloc( LMEM_FIXED, sizeof(DSDeviceNameAndGUID) * size * 2 );
    if( newItems == NULL )
    {
        result = paInsufficientMemory;
    }
    else
    {
        for( i=0; i < guidVector->count; ++i )
        {
            newItems[i].name = guidVector->items[i].name;
            if( guidVector->items[i].lpGUID == NULL )
            {
                newItems[i].lpGUID = NULL;
            }
            else
            {
                newItems[i].lpGUID = &newItems[i].guid;
                memcpy( &newItems[i].guid, guidVector->items[i].lpGUID, sizeof(GUID) );;
            }
        }

        LocalFree( guidVector->items );
        guidVector->items = newItems;
    }                                

    return result;
}

/*
    it's safe to call DSDeviceNameAndGUIDVector multiple times
*/
static PaError TerminateDSDeviceNameAndGUIDVector( DSDeviceNameAndGUIDVector *guidVector )
{
    PaError result = paNoError;

    if( guidVector->items != NULL )
    {
        if( LocalFree( guidVector->items ) != NULL )
            result = paInsufficientMemory;              /** @todo this isn't the correct error to return from a deallocation failure */

        guidVector->items = NULL;
    }

    return result;
}

/************************************************************************************
** Collect preliminary device information during DirectSound enumeration 
*/
static BOOL CALLBACK CollectGUIDsProc(LPGUID lpGUID,
                                     LPCTSTR lpszDesc,
                                     LPCTSTR lpszDrvName,
                                     LPVOID lpContext )
{
    DSDeviceNameAndGUIDVector *namesAndGUIDs = (DSDeviceNameAndGUIDVector*)lpContext;
    PaError error;

    (void) lpszDrvName; /* unused variable */

    if( namesAndGUIDs->free == 0 )
    {
        error = ExpandDSDeviceNameAndGUIDVector( namesAndGUIDs );
        if( error != paNoError )
        {
            namesAndGUIDs->enumerationError = error;
            return FALSE;
        }
    }
    
    /* Set GUID pointer, copy GUID to storage in DSDeviceNameAndGUIDVector. */
    if( lpGUID == NULL )
    {
        namesAndGUIDs->items[namesAndGUIDs->count].lpGUID = NULL;
    }
    else
    {
        namesAndGUIDs->items[namesAndGUIDs->count].lpGUID =
                &namesAndGUIDs->items[namesAndGUIDs->count].guid;
      
        memcpy( &namesAndGUIDs->items[namesAndGUIDs->count].guid, lpGUID, sizeof(GUID) );
    }

    namesAndGUIDs->items[namesAndGUIDs->count].name =
            DuplicateDeviceNameString( namesAndGUIDs->allocations, lpszDesc );
    if( namesAndGUIDs->items[namesAndGUIDs->count].name == NULL )
    {
        namesAndGUIDs->enumerationError = paInsufficientMemory;
        return FALSE;
    }

    ++namesAndGUIDs->count;
    --namesAndGUIDs->free;
    
    return TRUE;
}


/* 
    GUIDs for emulated devices which we blacklist below.
    are there more than two of them??
*/

GUID IID_IRolandVSCEmulated1 = {0xc2ad1800, 0xb243, 0x11ce, 0xa8, 0xa4, 0x00, 0xaa, 0x00, 0x6c, 0x45, 0x01};
GUID IID_IRolandVSCEmulated2 = {0xc2ad1800, 0xb243, 0x11ce, 0xa8, 0xa4, 0x00, 0xaa, 0x00, 0x6c, 0x45, 0x02};


#define PA_DEFAULTSAMPLERATESEARCHORDER_COUNT_  (13) /* must match array length below */
static double defaultSampleRateSearchOrder_[] =
    { 44100.0, 48000.0, 32000.0, 24000.0, 22050.0, 88200.0, 96000.0, 192000.0,
        16000.0, 12000.0, 11025.0, 9600.0, 8000.0 };


/************************************************************************************
** Extract capabilities from an output device, and add it to the device info list
** if successful. This function assumes that there is enough room in the
** device info list to accomodate all entries.
**
** The device will not be added to the device list if any errors are encountered.
*/
static PaError AddOutputDeviceInfoFromDirectSound(
        PaWinDsHostApiRepresentation *winDsHostApi, char *name, LPGUID lpGUID )
{
    PaUtilHostApiRepresentation  *hostApi = &winDsHostApi->inheritedHostApiRep;
    PaDeviceInfo                 *deviceInfo = hostApi->deviceInfos[hostApi->info.deviceCount];
    PaWinDsDeviceInfo            *winDsDeviceInfo = &winDsHostApi->winDsDeviceInfos[hostApi->info.deviceCount];
    HRESULT                       hr;
    LPDIRECTSOUND                 lpDirectSound;
    DSCAPS                        caps;
    int                           deviceOK = TRUE;
    PaError                       result = paNoError;
    int                           i;
    
    /* Copy GUID to the device info structure. Set pointer. */
    if( lpGUID == NULL )
    {
        winDsDeviceInfo->lpGUID = NULL;
    }
    else
    {
        memcpy( &winDsDeviceInfo->guid, lpGUID, sizeof(GUID) );
        winDsDeviceInfo->lpGUID = &winDsDeviceInfo->guid;
    }

    
    if( lpGUID )
    {
        if (IsEqualGUID (&IID_IRolandVSCEmulated1,lpGUID) ||
            IsEqualGUID (&IID_IRolandVSCEmulated2,lpGUID) )
        {
            PA_DEBUG(("BLACKLISTED: %s \n",name));
            return paNoError;
        }
    }

    /* Create a DirectSound object for the specified GUID
        Note that using CoCreateInstance doesn't work on windows CE.
    */
    hr = paWinDsDSoundEntryPoints.DirectSoundCreate( lpGUID, &lpDirectSound, NULL );

    /** try using CoCreateInstance because DirectSoundCreate was hanging under
        some circumstances - note this was probably related to the
        #define BOOL short bug which has now been fixed
        @todo delete this comment and the following code once we've ensured
        there is no bug.
    */
    /*
    hr = CoCreateInstance( &CLSID_DirectSound, NULL, CLSCTX_INPROC_SERVER,
            &IID_IDirectSound, (void**)&lpDirectSound );

    if( hr == S_OK )
    {
        hr = IDirectSound_Initialize( lpDirectSound, lpGUID );
    }
    */
    
    if( hr != DS_OK )
    {
        if (hr == DSERR_ALLOCATED)
            PA_DEBUG(("AddOutputDeviceInfoFromDirectSound %s DSERR_ALLOCATED\n",name));
        DBUG(("Cannot create DirectSound for %s. Result = 0x%x\n", name, hr ));
        if (lpGUID)
            DBUG(("%s's GUID: {0x%x,0x%x,0x%x,0x%x,0x%x,0x%x,0x%x,0x%x,0x%x,0x%x, 0x%x} \n",
                 name,
                 lpGUID->Data1,
                 lpGUID->Data2,
                 lpGUID->Data3,
                 lpGUID->Data4[0],
                 lpGUID->Data4[1],
                 lpGUID->Data4[2],
                 lpGUID->Data4[3],
                 lpGUID->Data4[4],
                 lpGUID->Data4[5],
                 lpGUID->Data4[6],
                 lpGUID->Data4[7]));

        deviceOK = FALSE;
    }
    else
    {
        /* Query device characteristics. */
        memset( &caps, 0, sizeof(caps) ); 
        caps.dwSize = sizeof(caps);
        hr = IDirectSound_GetCaps( lpDirectSound, &caps );
        if( hr != DS_OK )
        {
            DBUG(("Cannot GetCaps() for DirectSound device %s. Result = 0x%x\n", name, hr ));
            deviceOK = FALSE;
        }
        else
        {

#ifndef PA_NO_WMME
            if( caps.dwFlags & DSCAPS_EMULDRIVER )
            {
                /* If WMME supported, then reject Emulated drivers because they are lousy. */
                deviceOK = FALSE;
            }
#endif

            if( deviceOK )
            {
                deviceInfo->maxInputChannels = 0;
                /* Mono or stereo device? */
                deviceInfo->maxOutputChannels = ( caps.dwFlags & DSCAPS_PRIMARYSTEREO ) ? PA_DS_MAX_CHANS : 1;

                deviceInfo->defaultLowInputLatency = 0.;    /** @todo IMPLEMENT ME */
                deviceInfo->defaultLowOutputLatency = 0.;   /** @todo IMPLEMENT ME */
                deviceInfo->defaultHighInputLatency = 0.;   /** @todo IMPLEMENT ME */
                deviceInfo->defaultHighOutputLatency = 0.;  /** @todo IMPLEMENT ME */
                
                /* initialize defaultSampleRate */
                
                if( caps.dwFlags & DSCAPS_CONTINUOUSRATE )
                {
                    /* initialize to caps.dwMaxSecondarySampleRate incase none of the standard rates match */
                    deviceInfo->defaultSampleRate = caps.dwMaxSecondarySampleRate;

                    for( i = 0; i < PA_DEFAULTSAMPLERATESEARCHORDER_COUNT_; ++i )
                    {
                        if( defaultSampleRateSearchOrder_[i] >= caps.dwMinSecondarySampleRate
                                && defaultSampleRateSearchOrder_[i] <= caps.dwMaxSecondarySampleRate ){

                            deviceInfo->defaultSampleRate = defaultSampleRateSearchOrder_[i];
                            break;
                        }
                    }
                }
                else if( caps.dwMinSecondarySampleRate == caps.dwMaxSecondarySampleRate )
                {
                    if( caps.dwMinSecondarySampleRate == 0 )
                    {
                        /*
                        ** On my Thinkpad 380Z, DirectSoundV6 returns min-max=0 !!
                        ** But it supports continuous sampling.
                        ** So fake range of rates, and hope it really supports it.
                        */
                        deviceInfo->defaultSampleRate = 44100.0f;

                        DBUG(("PA - Reported rates both zero. Setting to fake values for device #%s\n", name ));
                    }
                    else
                    {
                            deviceInfo->defaultSampleRate = caps.dwMaxSecondarySampleRate;
                    }
                }
                else if( (caps.dwMinSecondarySampleRate < 1000.0) && (caps.dwMaxSecondarySampleRate > 50000.0) )
                {
                    /* The EWS88MT drivers lie, lie, lie. The say they only support two rates, 100 & 100000.
                    ** But we know that they really support a range of rates!
                    ** So when we see a ridiculous set of rates, assume it is a range.
                    */
                  deviceInfo->defaultSampleRate = 44100.0f;
                  DBUG(("PA - Sample rate range used instead of two odd values for device #%s\n", name ));
                }
                else deviceInfo->defaultSampleRate = caps.dwMaxSecondarySampleRate;


                //printf( "min %d max %d\n", caps.dwMinSecondarySampleRate, caps.dwMaxSecondarySampleRate );
                // dwFlags | DSCAPS_CONTINUOUSRATE 
            }
        }

        IDirectSound_Release( lpDirectSound );
    }

    if( deviceOK )
    {
        deviceInfo->name = name;

        if( lpGUID == NULL )
            hostApi->info.defaultOutputDevice = hostApi->info.deviceCount;
            
        hostApi->info.deviceCount++;
    }

    return result;
}


/************************************************************************************
** Extract capabilities from an input device, and add it to the device info list
** if successful. This function assumes that there is enough room in the
** device info list to accomodate all entries.
**
** The device will not be added to the device list if any errors are encountered.
*/
static PaError AddInputDeviceInfoFromDirectSoundCapture(
        PaWinDsHostApiRepresentation *winDsHostApi, char *name, LPGUID lpGUID )
{
    PaUtilHostApiRepresentation  *hostApi = &winDsHostApi->inheritedHostApiRep;
    PaDeviceInfo                 *deviceInfo = hostApi->deviceInfos[hostApi->info.deviceCount];
    PaWinDsDeviceInfo            *winDsDeviceInfo = &winDsHostApi->winDsDeviceInfos[hostApi->info.deviceCount];
    HRESULT                       hr;
    LPDIRECTSOUNDCAPTURE          lpDirectSoundCapture;
    DSCCAPS                       caps;
    int                           deviceOK = TRUE;
    PaError                       result = paNoError;
    
    /* Copy GUID to the device info structure. Set pointer. */
    if( lpGUID == NULL )
    {
        winDsDeviceInfo->lpGUID = NULL;
    }
    else
    {
        winDsDeviceInfo->lpGUID = &winDsDeviceInfo->guid;
        memcpy( &winDsDeviceInfo->guid, lpGUID, sizeof(GUID) );
    }


    hr = paWinDsDSoundEntryPoints.DirectSoundCaptureCreate( lpGUID, &lpDirectSoundCapture, NULL );

    /** try using CoCreateInstance because DirectSoundCreate was hanging under
        some circumstances - note this was probably related to the
        #define BOOL short bug which has now been fixed
        @todo delete this comment and the following code once we've ensured
        there is no bug.
    */
    /*
    hr = CoCreateInstance( &CLSID_DirectSoundCapture, NULL, CLSCTX_INPROC_SERVER,
            &IID_IDirectSoundCapture, (void**)&lpDirectSoundCapture );
    */
    if( hr != DS_OK )
    {
        DBUG(("Cannot create Capture for %s. Result = 0x%x\n", name, hr ));
        deviceOK = FALSE;
    }
    else
    {
        /* Query device characteristics. */
        memset( &caps, 0, sizeof(caps) );
        caps.dwSize = sizeof(caps);
        hr = IDirectSoundCapture_GetCaps( lpDirectSoundCapture, &caps );
        if( hr != DS_OK )
        {
            DBUG(("Cannot GetCaps() for Capture device %s. Result = 0x%x\n", name, hr ));
            deviceOK = FALSE;
        }
        else
        {
#ifndef PA_NO_WMME
            if( caps.dwFlags & DSCAPS_EMULDRIVER )
            {
                /* If WMME supported, then reject Emulated drivers because they are lousy. */
                deviceOK = FALSE;
            }
#endif

            if( deviceOK )
            {
                deviceInfo->maxInputChannels = caps.dwChannels;
                deviceInfo->maxOutputChannels = 0;

                deviceInfo->defaultLowInputLatency = 0.;    /** @todo IMPLEMENT ME */
                deviceInfo->defaultLowOutputLatency = 0.;   /** @todo IMPLEMENT ME */
                deviceInfo->defaultHighInputLatency = 0.;   /** @todo IMPLEMENT ME */
                deviceInfo->defaultHighOutputLatency = 0.;  /** @todo IMPLEMENT ME */

/*  constants from a WINE patch by Francois Gouget, see:
    http://www.winehq.com/hypermail/wine-patches/2003/01/0290.html

    ---
    Date: Fri, 14 May 2004 10:38:12 +0200 (CEST)
    From: Francois Gouget <fgouget@ ... .fr>
    To: Ross Bencina <rbencina@ ... .au>
    Subject: Re: Permission to use wine 48/96 wave patch in BSD licensed library

    [snip]

    I give you permission to use the patch below under the BSD license.
    http://www.winehq.com/hypermail/wine-patches/2003/01/0290.html

    [snip]
*/
#ifndef WAVE_FORMAT_48M08
#define WAVE_FORMAT_48M08      0x00001000    /* 48     kHz, Mono,   8-bit  */
#define WAVE_FORMAT_48S08      0x00002000    /* 48     kHz, Stereo, 8-bit  */
#define WAVE_FORMAT_48M16      0x00004000    /* 48     kHz, Mono,   16-bit */
#define WAVE_FORMAT_48S16      0x00008000    /* 48     kHz, Stereo, 16-bit */
#define WAVE_FORMAT_96M08      0x00010000    /* 96     kHz, Mono,   8-bit  */
#define WAVE_FORMAT_96S08      0x00020000    /* 96     kHz, Stereo, 8-bit  */
#define WAVE_FORMAT_96M16      0x00040000    /* 96     kHz, Mono,   16-bit */
#define WAVE_FORMAT_96S16      0x00080000    /* 96     kHz, Stereo, 16-bit */
#endif

                /* defaultSampleRate */
                if( caps.dwChannels == 2 )
                {
                    if( caps.dwFormats & WAVE_FORMAT_4S16 )
                        deviceInfo->defaultSampleRate = 44100.0;
                    else if( caps.dwFormats & WAVE_FORMAT_48S16 )
                        deviceInfo->defaultSampleRate = 48000.0;
                    else if( caps.dwFormats & WAVE_FORMAT_2S16 )
                        deviceInfo->defaultSampleRate = 22050.0;
                    else if( caps.dwFormats & WAVE_FORMAT_1S16 )
                        deviceInfo->defaultSampleRate = 11025.0;
                    else if( caps.dwFormats & WAVE_FORMAT_96S16 )
                        deviceInfo->defaultSampleRate = 96000.0;
                    else
                        deviceInfo->defaultSampleRate = 0.;
                }
                else if( caps.dwChannels == 1 )
                {
                    if( caps.dwFormats & WAVE_FORMAT_4M16 )
                        deviceInfo->defaultSampleRate = 44100.0;
                    else if( caps.dwFormats & WAVE_FORMAT_48M16 )
                        deviceInfo->defaultSampleRate = 48000.0;
                    else if( caps.dwFormats & WAVE_FORMAT_2M16 )
                        deviceInfo->defaultSampleRate = 22050.0;
                    else if( caps.dwFormats & WAVE_FORMAT_1M16 )
                        deviceInfo->defaultSampleRate = 11025.0;
                    else if( caps.dwFormats & WAVE_FORMAT_96M16 )
                        deviceInfo->defaultSampleRate = 96000.0;
                    else
                        deviceInfo->defaultSampleRate = 0.;
                }
                else deviceInfo->defaultSampleRate = 0.;
            }
        }
        
        IDirectSoundCapture_Release( lpDirectSoundCapture );
    }

    if( deviceOK )
    {
        deviceInfo->name = name;

        if( lpGUID == NULL )
            hostApi->info.defaultInputDevice = hostApi->info.deviceCount;

        hostApi->info.deviceCount++;
    }

    return result;
}


/***********************************************************************************/
PaError PaWinDs_Initialize( PaUtilHostApiRepresentation **hostApi, PaHostApiIndex hostApiIndex )
{
    PaError result = paNoError;
    int i, deviceCount;
    PaWinDsHostApiRepresentation *winDsHostApi;
    DSDeviceNameAndGUIDVector inputNamesAndGUIDs, outputNamesAndGUIDs;
    PaDeviceInfo *deviceInfoArray;

    HRESULT hr = CoInitialize(NULL);        /** @todo: should uninitialize too */
    if( FAILED(hr) ){
        return paUnanticipatedHostError;
    }            

    /* initialise guid vectors so they can be safely deleted on error */
    inputNamesAndGUIDs.items = NULL;
    outputNamesAndGUIDs.items = NULL;

    PaWinDs_InitializeDSoundEntryPoints();

    winDsHostApi = (PaWinDsHostApiRepresentation*)PaUtil_AllocateMemory( sizeof(PaWinDsHostApiRepresentation) );
    if( !winDsHostApi )
    {
        result = paInsufficientMemory;
        goto error;
    }

    winDsHostApi->allocations = PaUtil_CreateAllocationGroup();
    if( !winDsHostApi->allocations )
    {
        result = paInsufficientMemory;
        goto error;
    }

    *hostApi = &winDsHostApi->inheritedHostApiRep;
    (*hostApi)->info.structVersion = 1;
    (*hostApi)->info.type = paDirectSound;
    (*hostApi)->info.name = "Windows DirectSound";
    
    (*hostApi)->info.deviceCount = 0;
    (*hostApi)->info.defaultInputDevice = paNoDevice;
    (*hostApi)->info.defaultOutputDevice = paNoDevice;

    
/* DSound - enumerate devices to count them and to gather their GUIDs */


    result = InitializeDSDeviceNameAndGUIDVector( &inputNamesAndGUIDs, winDsHostApi->allocations );
    if( result != paNoError )
        goto error;

    result = InitializeDSDeviceNameAndGUIDVector( &outputNamesAndGUIDs, winDsHostApi->allocations );
    if( result != paNoError )
        goto error;

    paWinDsDSoundEntryPoints.DirectSoundCaptureEnumerate( (LPDSENUMCALLBACK)CollectGUIDsProc, (void *)&inputNamesAndGUIDs );

    paWinDsDSoundEntryPoints.DirectSoundEnumerate( (LPDSENUMCALLBACK)CollectGUIDsProc, (void *)&outputNamesAndGUIDs );

    if( inputNamesAndGUIDs.enumerationError != paNoError )
    {
        result = inputNamesAndGUIDs.enumerationError;
        goto error;
    }

    if( outputNamesAndGUIDs.enumerationError != paNoError )
    {
        result = outputNamesAndGUIDs.enumerationError;
        goto error;
    }

    deviceCount = inputNamesAndGUIDs.count + outputNamesAndGUIDs.count;

    if( deviceCount > 0 )
    {
        /* allocate array for pointers to PaDeviceInfo structs */
        (*hostApi)->deviceInfos = (PaDeviceInfo**)PaUtil_GroupAllocateMemory(
                winDsHostApi->allocations, sizeof(PaDeviceInfo*) * deviceCount );
        if( !(*hostApi)->deviceInfos )
        {
            result = paInsufficientMemory;
            goto error;
        }

        /* allocate all PaDeviceInfo structs in a contiguous block */
        deviceInfoArray = (PaDeviceInfo*)PaUtil_GroupAllocateMemory(
                winDsHostApi->allocations, sizeof(PaDeviceInfo) * deviceCount );
        if( !deviceInfoArray )
        {
            result = paInsufficientMemory;
            goto error;
        }

        /* allocate all DSound specific info structs in a contiguous block */
        winDsHostApi->winDsDeviceInfos = (PaWinDsDeviceInfo*)PaUtil_GroupAllocateMemory(
                winDsHostApi->allocations, sizeof(PaWinDsDeviceInfo) * deviceCount );
        if( !winDsHostApi->winDsDeviceInfos )
        {
            result = paInsufficientMemory;
            goto error;
        }

        for( i=0; i < deviceCount; ++i )
        {
            PaDeviceInfo *deviceInfo = &deviceInfoArray[i];
            deviceInfo->structVersion = 2;
            deviceInfo->hostApi = hostApiIndex;
            deviceInfo->name = 0;
            (*hostApi)->deviceInfos[i] = deviceInfo;
        }

        for( i=0; i< inputNamesAndGUIDs.count; ++i )
        {
            result = AddInputDeviceInfoFromDirectSoundCapture( winDsHostApi,
                    inputNamesAndGUIDs.items[i].name,
                    inputNamesAndGUIDs.items[i].lpGUID );
            if( result != paNoError )
                goto error;
        }

        for( i=0; i< outputNamesAndGUIDs.count; ++i )
        {
            result = AddOutputDeviceInfoFromDirectSound( winDsHostApi,
                    outputNamesAndGUIDs.items[i].name,
                    outputNamesAndGUIDs.items[i].lpGUID );
            if( result != paNoError )
                goto error;
        }
    }    

    result = TerminateDSDeviceNameAndGUIDVector( &inputNamesAndGUIDs );
    if( result != paNoError )
        goto error;

    result = TerminateDSDeviceNameAndGUIDVector( &outputNamesAndGUIDs );
    if( result != paNoError )
        goto error;

    
    (*hostApi)->Terminate = Terminate;
    (*hostApi)->OpenStream = OpenStream;
    (*hostApi)->IsFormatSupported = IsFormatSupported;

    PaUtil_InitializeStreamInterface( &winDsHostApi->callbackStreamInterface, CloseStream, StartStream,
                                      StopStream, AbortStream, IsStreamStopped, IsStreamActive,
                                      GetStreamTime, GetStreamCpuLoad,
                                      PaUtil_DummyRead, PaUtil_DummyWrite,
                                      PaUtil_DummyGetReadAvailable, PaUtil_DummyGetWriteAvailable );

    PaUtil_InitializeStreamInterface( &winDsHostApi->blockingStreamInterface, CloseStream, StartStream,
                                      StopStream, AbortStream, IsStreamStopped, IsStreamActive,
                                      GetStreamTime, PaUtil_DummyGetCpuLoad,
                                      ReadStream, WriteStream, GetStreamReadAvailable, GetStreamWriteAvailable );

    return result;

error:
    if( winDsHostApi )
    {
        if( winDsHostApi->allocations )
        {
            PaUtil_FreeAllAllocations( winDsHostApi->allocations );
            PaUtil_DestroyAllocationGroup( winDsHostApi->allocations );
        }
                
        PaUtil_FreeMemory( winDsHostApi );
    }

    TerminateDSDeviceNameAndGUIDVector( &inputNamesAndGUIDs );
    TerminateDSDeviceNameAndGUIDVector( &outputNamesAndGUIDs );

    return result;
}


/***********************************************************************************/
static void Terminate( struct PaUtilHostApiRepresentation *hostApi )
{
    PaWinDsHostApiRepresentation *winDsHostApi = (PaWinDsHostApiRepresentation*)hostApi;

    /*
        IMPLEMENT ME:
            - clean up any resources not handled by the allocation group
    */

    if( winDsHostApi->allocations )
    {
        PaUtil_FreeAllAllocations( winDsHostApi->allocations );
        PaUtil_DestroyAllocationGroup( winDsHostApi->allocations );
    }

    PaUtil_FreeMemory( winDsHostApi );

    PaWinDs_TerminateDSoundEntryPoints();

    CoUninitialize();
}


/* Set minimal latency based on whether NT or Win95.
 * NT has higher latency.
 */
static int PaWinDS_GetMinSystemLatency( void )
{
    int minLatencyMsec;
    /* Set minimal latency based on whether NT or other OS.
     * NT has higher latency.
     */
    OSVERSIONINFO osvi;
        osvi.dwOSVersionInfoSize = sizeof( osvi );
        GetVersionEx( &osvi );
    DBUG(("PA - PlatformId = 0x%x\n", osvi.dwPlatformId ));
    DBUG(("PA - MajorVersion = 0x%x\n", osvi.dwMajorVersion ));
    DBUG(("PA - MinorVersion = 0x%x\n", osvi.dwMinorVersion ));
    /* Check for NT */
        if( (osvi.dwMajorVersion == 4) && (osvi.dwPlatformId == 2) )
        {
                minLatencyMsec = PA_WIN_NT_LATENCY;
        }
        else if(osvi.dwMajorVersion >= 5)
        {
                minLatencyMsec = PA_WIN_WDM_LATENCY;
        }
        else
        {
                minLatencyMsec = PA_WIN_9X_LATENCY;
        }
    return minLatencyMsec;
}

/***********************************************************************************/
static PaError IsFormatSupported( struct PaUtilHostApiRepresentation *hostApi,
                                  const PaStreamParameters *inputParameters,
                                  const PaStreamParameters *outputParameters,
                                  double sampleRate )
{
    int inputChannelCount, outputChannelCount;
    PaSampleFormat inputSampleFormat, outputSampleFormat;
    
    if( inputParameters )
    {
        inputChannelCount = inputParameters->channelCount;
        inputSampleFormat = inputParameters->sampleFormat;

        /* unless alternate device specification is supported, reject the use of
            paUseHostApiSpecificDeviceSpecification */

        if( inputParameters->device == paUseHostApiSpecificDeviceSpecification )
            return paInvalidDevice;

        /* check that input device can support inputChannelCount */
        if( inputChannelCount > hostApi->deviceInfos[ inputParameters->device ]->maxInputChannels )
            return paInvalidChannelCount;

        /* validate inputStreamInfo */
        if( inputParameters->hostApiSpecificStreamInfo )
            return paIncompatibleHostApiSpecificStreamInfo; /* this implementation doesn't use custom stream info */
    }
    else
    {
        inputChannelCount = 0;
    }

    if( outputParameters )
    {
        outputChannelCount = outputParameters->channelCount;
        outputSampleFormat = outputParameters->sampleFormat;
        
        /* unless alternate device specification is supported, reject the use of
            paUseHostApiSpecificDeviceSpecification */

        if( outputParameters->device == paUseHostApiSpecificDeviceSpecification )
            return paInvalidDevice;

        /* check that output device can support inputChannelCount */
        if( outputChannelCount > hostApi->deviceInfos[ outputParameters->device ]->maxOutputChannels )
            return paInvalidChannelCount;

        /* validate outputStreamInfo */
        if( outputParameters->hostApiSpecificStreamInfo )
            return paIncompatibleHostApiSpecificStreamInfo; /* this implementation doesn't use custom stream info */
    }
    else
    {
        outputChannelCount = 0;
    }
    
    /*
        IMPLEMENT ME:

            - if a full duplex stream is requested, check that the combination
                of input and output parameters is supported if necessary

            - check that the device supports sampleRate

        Because the buffer adapter handles conversion between all standard
        sample formats, the following checks are only required if paCustomFormat
        is implemented, or under some other unusual conditions.

            - check that input device can support inputSampleFormat, or that
                we have the capability to convert from outputSampleFormat to
                a native format

            - check that output device can support outputSampleFormat, or that
                we have the capability to convert from outputSampleFormat to
                a native format
    */

    return paFormatIsSupported;
}


/*************************************************************************
** Determine minimum number of buffers required for this host based
** on minimum latency. Latency can be optionally set by user by setting
** an environment variable. For example, to set latency to 200 msec, put:
**
**    set PA_MIN_LATENCY_MSEC=200
**
** in the AUTOEXEC.BAT file and reboot.
** If the environment variable is not set, then the latency will be determined
** based on the OS. Windows NT has higher latency than Win95.
*/
#define PA_LATENCY_ENV_NAME  ("PA_MIN_LATENCY_MSEC")
#define PA_ENV_BUF_SIZE  (32)

static int PaWinDs_GetMinLatencyFrames( double sampleRate )
{
    char      envbuf[PA_ENV_BUF_SIZE];
    DWORD     hresult;
    int       minLatencyMsec = 0;

    /* Let user determine minimal latency by setting environment variable. */
    hresult = GetEnvironmentVariable( PA_LATENCY_ENV_NAME, envbuf, PA_ENV_BUF_SIZE );
    if( (hresult > 0) && (hresult < PA_ENV_BUF_SIZE) )
    {
        minLatencyMsec = atoi( envbuf );
    }
    else
    {
        minLatencyMsec = PaWinDS_GetMinSystemLatency();
#if PA_USE_HIGH_LATENCY
        PRINT(("PA - Minimum Latency set to %d msec!\n", minLatencyMsec ));
#endif

    }

    return (int) (minLatencyMsec * sampleRate * SECONDS_PER_MSEC);
}

/* Initialize a WAVEFORMATEXTENSIBLE structure, possibly using only those fields found in a WAVEFORMATEX */
static void initWaveformat(WAVEFORMATEXTENSIBLE *pwfFormat, BOOL bUseExtensible, 
                           PaSampleFormat sampleFormat, int nChannels, unsigned long nFrameRate) 
{
    int bytesPerSample = Pa_GetSampleSize(sampleFormat);
    int bitsPerSample  = bytesPerSample*8;

  /* Initialize the fields common to both structures */
    pwfFormat->Format.nChannels       = nChannels;
    pwfFormat->Format.nSamplesPerSec  = nFrameRate;
    pwfFormat->Format.wBitsPerSample  = bitsPerSample;
    pwfFormat->Format.nBlockAlign     = (WORD)(pwfFormat->Format.nChannels * bytesPerSample);
    pwfFormat->Format.nAvgBytesPerSec = pwfFormat->Format.nSamplesPerSec * pwfFormat->Format.nBlockAlign;

    /* Initialize as WAVEFORMATEX */
    if(!bUseExtensible) {
        pwfFormat->Format.wFormatTag      = WAVE_FORMAT_PCM;
        pwfFormat->Format.cbSize          = 0;
    }

    /* Initialize as WAVEFORMATEXTENSIBLE */
    else {
        int i;
        pwfFormat->Format.wFormatTag           = WAVE_FORMAT_EXTENSIBLE;
        pwfFormat->Format.cbSize               = 22;
        pwfFormat->Samples.wValidBitsPerSample = pwfFormat->Format.wBitsPerSample;
        if(sampleFormat==paFloat32)
            pwfFormat->SubFormat = KSDATAFORMAT_SUBTYPE_IEEE_FLOAT;
        else
            pwfFormat->SubFormat = KSDATAFORMAT_SUBTYPE_PCM;
        /* If the input is monophonic, send the data to the front center channel.
           Otherwise, fill out the channel mask such that channels are sent to the first N channels. */
        if(nChannels==1) {
            pwfFormat->dwChannelMask = SPEAKER_FRONT_CENTER;
        }
        else {
            pwfFormat->dwChannelMask = 0;
            for(i=0; i<nChannels; i++)
                pwfFormat->dwChannelMask = (pwfFormat->dwChannelMask << 1) | 0x1;
        }
    }
}

static HRESULT InitInputBuffer( PaWinDsStream *stream, PaSampleFormat sampleFormat, unsigned long nFrameRate, WORD nChannels, int bytesPerBuffer )
{
    DSCBUFFERDESC  captureDesc;
    WAVEFORMATEXTENSIBLE  wfFormat;
    HRESULT        result;

    stream->bytesPerInputFrame = nChannels * Pa_GetSampleSize(sampleFormat);
    stream->inputSize = bytesPerBuffer;
    // ----------------------------------------------------------------------
    // Setup the secondary buffer description
    ZeroMemory(&captureDesc, sizeof(DSCBUFFERDESC));
    captureDesc.dwSize = sizeof(DSCBUFFERDESC);
    captureDesc.dwFlags =  0;
    captureDesc.dwBufferBytes = bytesPerBuffer;
    captureDesc.lpwfxFormat = (WAVEFORMATEX*)&wfFormat;

    // Attempt to create the capture buffer with WAVEFORMATEXTENSIBLE
    initWaveformat(&wfFormat, TRUE, sampleFormat, nChannels, nFrameRate);
    result = IDirectSoundCapture_CreateCaptureBuffer( stream->pDirectSoundCapture,
                 &captureDesc, &stream->pDirectSoundInputBuffer, NULL);
    if(result != DS_OK) {
        // Attempt to create the capture buffer with WAVEFORMATEX
        initWaveformat(&wfFormat, FALSE, sampleFormat, nChannels, nFrameRate);
        result = IDirectSoundCapture_CreateCaptureBuffer( stream->pDirectSoundCapture,
                     &captureDesc, &stream->pDirectSoundInputBuffer, NULL);
    }
    if(result != DS_OK) return result;
    stream->readOffset = 0;  // reset last read position to start of buffer
    return DS_OK;
}


static HRESULT InitOutputBuffer( PaWinDsStream *stream, PaSampleFormat sampleFormat, unsigned long nFrameRate, WORD nChannels, int bytesPerBuffer )
{
    DWORD          dwDataLen;
    DWORD          playCursor;
    HRESULT        result;
    LPDIRECTSOUNDBUFFER pPrimaryBuffer;
    HWND           hWnd;
    HRESULT        hr;
    WAVEFORMATEXTENSIBLE wfFormat;
    DSBUFFERDESC   primaryDesc;
    DSBUFFERDESC   secondaryDesc;
    unsigned char* pDSBuffData;
    LARGE_INTEGER  counterFrequency;
    int bytesPerSample = Pa_GetSampleSize(sampleFormat);

    stream->outputBufferSizeBytes = bytesPerBuffer;
    stream->outputIsRunning = FALSE;
    stream->outputUnderflowCount = 0;
    stream->dsw_framesWritten = 0;
    stream->bytesPerOutputFrame = nChannels * bytesPerSample;

    // We were using getForegroundWindow() but sometimes the ForegroundWindow may not be the
    // applications's window. Also if that window is closed before the Buffer is closed
    // then DirectSound can crash. (Thanks for Scott Patterson for reporting this.)
    // So we will use GetDesktopWindow() which was suggested by Miller Puckette.
    // hWnd = GetForegroundWindow();
    //
    //  FIXME: The example code I have on the net creates a hidden window that
    //      is managed by our code - I think we should do that - one hidden
    //      window for the whole of Pa_DS
    //
    hWnd = GetDesktopWindow();

    // Set cooperative level to DSSCL_EXCLUSIVE so that we can get 16 bit output, 44.1 KHz.
    // Exclusize also prevents unexpected sounds from other apps during a performance.
    if ((hr = IDirectSound_SetCooperativeLevel( stream->pDirectSound,
              hWnd, DSSCL_EXCLUSIVE)) != DS_OK)
    {
        return hr;
    }

    // -----------------------------------------------------------------------
    // Create primary buffer and set format just so we can specify our custom format.
    // Otherwise we would be stuck with the default which might be 8 bit or 22050 Hz.
    // Setup the primary buffer description
    ZeroMemory(&primaryDesc, sizeof(DSBUFFERDESC));
    primaryDesc.dwSize        = sizeof(DSBUFFERDESC);
    primaryDesc.dwFlags       = DSBCAPS_PRIMARYBUFFER; // all panning, mixing, etc done by synth
    primaryDesc.dwBufferBytes = 0;
    primaryDesc.lpwfxFormat   = NULL;
    // Create the buffer
    if ((result = IDirectSound_CreateSoundBuffer( stream->pDirectSound,
                  &primaryDesc, &pPrimaryBuffer, NULL))