pa_linux_alsa.c

一个开源的sip源代码

            snd_pcm_info_set_device( pcmInfo, devIdx );
            snd_pcm_info_set_subdevice( pcmInfo, 0 );
            snd_pcm_info_set_stream( pcmInfo, SND_PCM_STREAM_CAPTURE );
            if( snd_ctl_pcm_info( ctl, pcmInfo ) >= 0 )
            {
                hasCapture = 1;
            }
            
            snd_pcm_info_set_stream( pcmInfo, SND_PCM_STREAM_PLAYBACK );
            if( snd_ctl_pcm_info( ctl, pcmInfo ) >= 0 )
            {
                hasPlayback = 1;
            }

            if( !hasPlayback && !hasCapture )
            {
                /* Error */
                continue;
            }

            /* The length of the string written by snprintf plus terminating 0 */
            len = snprintf( NULL, 0, "%s: %s (%s)", cardName, snd_pcm_info_get_name( pcmInfo ), buf ) + 1;
            PA_UNLESS( deviceName = (char *)PaUtil_GroupAllocateMemory( alsaApi->allocations, len ),
                    paInsufficientMemory );
            snprintf( deviceName, len, "%s: %s (%s)", cardName,
                    snd_pcm_info_get_name( pcmInfo ), buf );

            ++numDeviceNames;
            if( !hwDevInfos || numDeviceNames > maxDeviceNames )
            {
                maxDeviceNames *= 2;
                PA_UNLESS( hwDevInfos = (HwDevInfo *) realloc( hwDevInfos, maxDeviceNames * sizeof (HwDevInfo) ),
                        paInsufficientMemory );
            }

            PA_ENSURE( PaAlsa_StrDup( alsaApi, &alsaDeviceName, buf ) );

            hwDevInfos[ numDeviceNames - 1 ].alsaName = alsaDeviceName;
            hwDevInfos[ numDeviceNames - 1 ].name = deviceName;
            hwDevInfos[ numDeviceNames - 1 ].isPlug = 0;
            hwDevInfos[ numDeviceNames - 1 ].hasPlayback = hasPlayback;
            hwDevInfos[ numDeviceNames - 1 ].hasCapture = hasCapture;
        }
        snd_ctl_close( ctl );
    }

    /* Iterate over plugin devices */

    if( NULL == snd_config )
    {
        /* snd_config_update is called implicitly by some functions, if this hasn't happened snd_config will be NULL (bleh) */
        ENSURE_( snd_config_update(), paUnanticipatedHostError );
        PA_DEBUG(( "Updating snd_config\n" ));
    }
    assert( snd_config );
    if( (res = snd_config_search( snd_config, "pcm", &topNode )) >= 0 )
    {
        snd_config_iterator_t i, next;

        snd_config_for_each( i, next, topNode )
        {
            const char *tpStr = "unknown", *idStr = NULL;
            int err = 0;

            char *alsaDeviceName, *deviceName;
	    const HwDevInfo *predefined = NULL;
            snd_config_t *n = snd_config_iterator_entry( i ), * tp = NULL;;

            if( (err = snd_config_search( n, "type", &tp )) < 0 )
            {
                if( -ENOENT != err )
                {
                    ENSURE_(err, paUnanticipatedHostError);
                }
            }
            else 
            {
                ENSURE_( snd_config_get_string( tp, &tpStr ), paUnanticipatedHostError );
            }
            ENSURE_( snd_config_get_id( n, &idStr ), paUnanticipatedHostError );
            if( IgnorePlugin( idStr ) )
            {
                PA_DEBUG(( "%s: Ignoring ALSA plugin device %s of type %s\n", __FUNCTION__, idStr, tpStr ));
                continue;
            }
            PA_DEBUG(( "%s: Found plugin %s of type %s\n", __FUNCTION__, idStr, tpStr ));

            PA_UNLESS( alsaDeviceName = (char*)PaUtil_GroupAllocateMemory( alsaApi->allocations,
                                                            strlen(idStr) + 6 ), paInsufficientMemory );
            strcpy( alsaDeviceName, idStr );
            PA_UNLESS( deviceName = (char*)PaUtil_GroupAllocateMemory( alsaApi->allocations,
                                                            strlen(idStr) + 1 ), paInsufficientMemory );
            strcpy( deviceName, idStr );

            ++numDeviceNames;
            if( !hwDevInfos || numDeviceNames > maxDeviceNames )
            {
                maxDeviceNames *= 2;
                PA_UNLESS( hwDevInfos = (HwDevInfo *) realloc( hwDevInfos, maxDeviceNames * sizeof (HwDevInfo) ),
                        paInsufficientMemory );
            }

	    predefined = FindDeviceName( alsaDeviceName );

            hwDevInfos[numDeviceNames - 1].alsaName = alsaDeviceName;
            hwDevInfos[numDeviceNames - 1].name = deviceName;
            hwDevInfos[numDeviceNames - 1].isPlug = 1;

	    if( predefined )
	    {
		hwDevInfos[numDeviceNames - 1].hasPlayback =
		    predefined->hasPlayback;
		hwDevInfos[numDeviceNames - 1].hasCapture =
		    predefined->hasCapture;
	    }
	    else
	    {
		hwDevInfos[numDeviceNames - 1].hasPlayback = 1;
		hwDevInfos[numDeviceNames - 1].hasCapture = 1;
	    }
        }
    }
    else
        PA_DEBUG(( "%s: Iterating over ALSA plugins failed: %s\n", __FUNCTION__, snd_strerror( res ) ));

    /* allocate deviceInfo memory based on the number of devices */
    PA_UNLESS( baseApi->deviceInfos = (PaDeviceInfo**)PaUtil_GroupAllocateMemory(
            alsaApi->allocations, sizeof(PaDeviceInfo*) * (numDeviceNames) ), paInsufficientMemory );

    /* allocate all device info structs in a contiguous block */
    PA_UNLESS( deviceInfoArray = (PaAlsaDeviceInfo*)PaUtil_GroupAllocateMemory(
            alsaApi->allocations, sizeof(PaAlsaDeviceInfo) * numDeviceNames ), paInsufficientMemory );

    /* Loop over list of cards, filling in info. If a device is deemed unavailable (can't get name),
     * it's ignored.
     */

    for( i = 0, devIdx = 0; i < numDeviceNames; ++i )
    {
        PaAlsaDeviceInfo* devInfo = &deviceInfoArray[i];
        HwDevInfo* hwInfo = &hwDevInfos[i];
        if( !strcmp( hwInfo->name, "dmix" ) || !strcmp( hwInfo->name, "default" ) )
        {
            continue;
        }

        PA_ENSURE( FillInDevInfo( alsaApi, hwInfo, blocking, devInfo, &devIdx ) );
    }
    assert( devIdx < numDeviceNames );
    for( i = 0; i < numDeviceNames; ++i )
    {
        PaAlsaDeviceInfo* devInfo = &deviceInfoArray[i];
        HwDevInfo* hwInfo = &hwDevInfos[i];
        if( strcmp( hwInfo->name, "dmix" ) && strcmp( hwInfo->name, "default" ) )
        {
            continue;
        }

        PA_ENSURE( FillInDevInfo( alsaApi, hwInfo, blocking, devInfo,
                    &devIdx ) );
    }
    free( hwDevInfos );

    baseApi->info.deviceCount = devIdx;   /* Number of successfully queried devices */

end:
    return result;

error:
    /* No particular action */
    goto end;
}

/* Check against known device capabilities */
static PaError ValidateParameters( const PaStreamParameters *parameters, PaUtilHostApiRepresentation *hostApi, StreamDirection mode )
{
    PaError result = paNoError;
    int maxChans;
    const PaAlsaDeviceInfo *deviceInfo = NULL;
    assert( parameters );

    if( parameters->device != paUseHostApiSpecificDeviceSpecification )
    {
        assert( parameters->device < hostApi->info.deviceCount );
        PA_UNLESS( parameters->hostApiSpecificStreamInfo == NULL, paBadIODeviceCombination );
        deviceInfo = GetDeviceInfo( hostApi, parameters->device );
    }
    else
    {
        const PaAlsaStreamInfo *streamInfo = parameters->hostApiSpecificStreamInfo;

        PA_UNLESS( parameters->device == paUseHostApiSpecificDeviceSpecification, paInvalidDevice );
        PA_UNLESS( streamInfo->size == sizeof (PaAlsaStreamInfo) && streamInfo->version == 1,
                paIncompatibleHostApiSpecificStreamInfo );
        PA_UNLESS( streamInfo->deviceString != NULL, paInvalidDevice );

        /* Skip further checking */
        return paNoError;
    }

    assert( deviceInfo );
    assert( parameters->hostApiSpecificStreamInfo == NULL );
    maxChans = (StreamDirection_In == mode ? deviceInfo->baseDeviceInfo.maxInputChannels :
        deviceInfo->baseDeviceInfo.maxOutputChannels);
    PA_UNLESS( parameters->channelCount <= maxChans, paInvalidChannelCount );

error:
    return result;
}

/* Given an open stream, what sample formats are available? */
static PaSampleFormat GetAvailableFormats( snd_pcm_t *pcm )
{
    PaSampleFormat available = 0;
    snd_pcm_hw_params_t *hwParams;
    snd_pcm_hw_params_alloca( &hwParams );

    snd_pcm_hw_params_any( pcm, hwParams );

    if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_FLOAT ) >= 0)
        available |= paFloat32;

    if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S32 ) >= 0)
        available |= paInt32;

#ifdef PA_LITTLE_ENDIAN
    if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S24_3LE ) >= 0)
        available |= paInt24;
#elif defined PA_BIG_ENDIAN
    if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S24_3BE ) >= 0)
        available |= paInt24;
#endif

    if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S16 ) >= 0)
        available |= paInt16;

    if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_U8 ) >= 0)
        available |= paUInt8;

    if( snd_pcm_hw_params_test_format( pcm, hwParams, SND_PCM_FORMAT_S8 ) >= 0)
        available |= paInt8;

    return available;
}

static snd_pcm_format_t Pa2AlsaFormat( PaSampleFormat paFormat )
{
    switch( paFormat )
    {
        case paFloat32:
            return SND_PCM_FORMAT_FLOAT;

        case paInt16:
            return SND_PCM_FORMAT_S16;

        case paInt24:
#ifdef PA_LITTLE_ENDIAN
            return SND_PCM_FORMAT_S24_3LE;
#elif defined PA_BIG_ENDIAN
            return SND_PCM_FORMAT_S24_3BE;
#endif

        case paInt32:
            return SND_PCM_FORMAT_S32;

        case paInt8:
            return SND_PCM_FORMAT_S8;

        case paUInt8:
            return SND_PCM_FORMAT_U8;

        default:
            return SND_PCM_FORMAT_UNKNOWN;
    }
}

/** Open an ALSA pcm handle.
 * 
 * The device to be open can be specified in a custom PaAlsaStreamInfo struct, or it will be a device number. In case of a
 * device number, it maybe specified through an env variable (PA_ALSA_PLUGHW) that we should open the corresponding plugin
 * device.
 */
static PaError AlsaOpen( const PaUtilHostApiRepresentation *hostApi, const PaStreamParameters *params, StreamDirection
        streamDir, snd_pcm_t **pcm )
{
    PaError result = paNoError;
    int ret;
    char dnameArray[50];
    const char* deviceName = dnameArray;
    const PaAlsaDeviceInfo *deviceInfo = NULL;
    PaAlsaStreamInfo *streamInfo = (PaAlsaStreamInfo *)params->hostApiSpecificStreamInfo;

    if( !streamInfo )
    {
        int usePlug = 0;
        deviceInfo = GetDeviceInfo( hostApi, params->device );
        
        /* If device name starts with hw: and PA_ALSA_PLUGHW is 1, we open the plughw device instead */
        if( !strncmp( "hw:", deviceInfo->alsaName, 3 ) && getenv( "PA_ALSA_PLUGHW" ) )
            usePlug = atoi( getenv( "PA_ALSA_PLUGHW" ) );
        if( usePlug )
            snprintf( dnameArray, 50, "plug%s", deviceInfo->alsaName );
        else
            deviceName = deviceInfo->alsaName;
    }
    else
        deviceName = streamInfo->deviceString;

    PA_DEBUG(( "%s: Opening device %s\n", __FUNCTION__, deviceName ));
    if( (ret = OpenPcm( pcm, deviceName, streamDir == StreamDirection_In ? SND_PCM_STREAM_CAPTURE : SND_PCM_STREAM_PLAYBACK,
                    SND_PCM_NONBLOCK )) < 0 )
    {
        /* Not to be closed */
        *pcm = NULL;
        if( -EBUSY == ret )
        {
            PA_DEBUG(( "%s: Device is busy\n", __FUNCTION__ ));
        }
        ENSURE_( ret, -EBUSY == ret ? paDeviceUnavailable : paBadIODeviceCombination );
    }
    ENSURE_( snd_pcm_nonblock( *pcm, 0 ), paUnanticipatedHostError );

end:
    return result;

error:
    goto end;
}

static PaError TestParameters( const PaUtilHostApiRepresentation *hostApi, const PaStreamParameters *parameters,
        double sampleRate, StreamDirection streamDir )
{
    PaError result = paNoError;
    snd_pcm_t *pcm = NULL;
    PaSampleFormat availableFormats;
    /* We are able to adapt to a number of channels less than what the device supports */
    unsigned int numHostChannels;
    PaSampleFormat hostFormat;
    snd_pcm_hw_params_t *hwParams;
    snd_pcm_hw_params_alloca( &hwParams );
    
    if( !parameters->hostApiSpecificStreamInfo )
    {
        const PaAlsaDeviceInfo *devInfo = GetDeviceInfo( hostApi, parameters->device );