drivers/audio/AudioOutputDeviceAsio.cpp

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 - 2008 Christian Schoenebeck                       *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#include "AudioOutputDeviceAsio.h"
#include "AudioOutputDeviceFactory.h"

#define kMaxInputChannels 32
#define kMaxOutputChannels 32
#define ASIO_MAX_DEVICE_INFO 32

#define NUM_STANDARDSAMPLINGRATES   3   /* 11.025, 22.05, 44.1 */
#define NUM_CUSTOMSAMPLINGRATES     9   /* must be the same number of elements as in the array below */
#define MAX_NUMSAMPLINGRATES  (NUM_STANDARDSAMPLINGRATES+NUM_CUSTOMSAMPLINGRATES)

// internal data storage
typedef struct DriverInfo
{
    // ASIOInit()
    ASIODriverInfo driverInfo;

    // ASIOGetChannels()
    long           numInputChannels;
    long           numOutputChannels;

    // ASIOGetBufferSize()
    long           minBufSize;
    long           maxBufSize;
    long           preferredBufSize;
    long           bufGranularity;
    long           chosenBufSize;

    // ASIOGetSampleRate()
    ASIOSampleRate sampleRate;
    int numSampleRates;
    std::vector<int> sampleRates;

    // ASIOOutputReady()
    bool           ASIOOutputReadySupported;

    // ASIOGetLatencies ()
    long           inputLatency;
    long           outputLatency;

    // ASIOCreateBuffers ()
    long numInputBuffers;       // becomes number of actual created input buffers
    long numOutputBuffers;      // becomes number of actual created output buffers
    ASIOBufferInfo bufferInfos[kMaxInputChannels + kMaxOutputChannels]; // buffer info's

    // ASIOGetChannelInfo()
    ASIOChannelInfo channelInfos[kMaxInputChannels + kMaxOutputChannels]; // channel info's
    // The above two arrays share the same indexing, as the data in them are linked together

    // Information from ASIOGetSamplePosition()
    // data is converted to double floats for easier use, however 64 bit integer can be used, too
    double         nanoSeconds;
    double         samples;
    double         tcSamples;   // time code samples

    // bufferSwitchTimeInfo()
    ASIOTime       tInfo;                       // time info state
    unsigned long  sysRefTime;      // system reference time, when bufferSwitch() was called

    // Signal the end of processing in this example
    bool           stopped;
} DriverInfo;

extern AsioDrivers* asioDrivers;
extern bool loadAsioDriver(char *name);
static ASIODriverInfo MyAsioDriverInfo;
static DriverInfo asioDriverInfo = {0};

static bool asioDriverOpened;
static bool AudioOutputDeviceAsioInstantiated = false;
static String currentAsioDriverName;
static std::vector<String> asioDriverList;
static bool asioDriverListLoaded = false;

namespace LinuxSampler {

// callback prototypes

ASIOCallbacks asioCallbacks;
ASIOBufferInfo bufferInfos[2];
AudioOutputDeviceAsio *GlobalAudioOutputDeviceAsioThisPtr;

void floatToASIOSTInt16LSB(float *in, void *dest, int numSamples) {
    int16_t *out = (int16_t *)dest;
    for(int i=0; i < numSamples ; i++) {
        float sample_point = in[i] * 32768.0f;
        if (sample_point < -32768.0) sample_point = -32768.0;
        if (sample_point >  32767.0) sample_point =  32767.0;
        out[i] = (int16_t)sample_point;
    }
}

void floatToASIOSTInt32LSB(float *in, void *dest, int numSamples) {
    int32_t *out = (int32_t *)dest;
    for(int i=0; i < numSamples ; i++) {
        double sample_point = in[i] * 2147483648.0;
        if (sample_point < - 2147483648.0) sample_point = -2147483648.0;
        if (sample_point >  2147483647.0) sample_point =  2147483647.0;
        out[i] = (int32_t)(sample_point);
    }
}

static bool ASIO_loadAsioDriver(char *name)
{
    dmsg(1,("ASIO_loadAsioDriver: trying to load '%s'\n",name));
        #ifdef  WINDOWS
                CoInitialize(0);
        #endif
        return loadAsioDriver(name);
}

int ASIO_OpenAndQueryDeviceInfo(char *driverName, DriverInfo *driverInfo, ASIODriverInfo *asioDriverInfo)
{
    ASIOSampleRate possibleSampleRates[]
        = {8000.0, 9600.0, 11025.0, 12000.0, 16000.0, 22050.0, 24000.0, 32000.0, 44100.0, 48000.0, 88200.0, 96000.0};

    ASIOChannelInfo channelInfos;
    ASIOError     asioError;

    dmsg(1,("ASIO_OpenAndQueryDeviceInfo driverName='%s' current='%s'\n",driverName, currentAsioDriverName.c_str() ));
    if(!strcmp(driverName, currentAsioDriverName.c_str() )) {
        // if the given ASIO driver name == current ASIO driver name and the driver
        // was already opened then do nothing
        if(asioDriverOpened) {
            dmsg(0,("asioDriver ALREADY OPENED, DOING NOTHING !\n"));
            return 0;
        }
    }
    else {
    dmsg(1,("driverName != currentAsioDriverName , new asio driver specified, opening device ....\n"));
        // if a new ASIO driver name was specified then first check if we need to close
        // the old one
        if(asioDriverOpened) {
            dmsg(0,("different asioDriver ALREADY OPENED, closing old one !\n"));
            asioDriverOpened = false;
            ASIOExit(); // close the old ASIO driver
        }
    }
    currentAsioDriverName = driverName;

        memset((void *)asioDriverInfo,0,sizeof(ASIODriverInfo));
    asioDriverInfo->asioVersion=1;
    asioDriverInfo->sysRef = NULL;

    /* MUST BE CHECKED : to force fragments loading on Mac */
    //ASIO_loadAsioDriver("dummy");

    dmsg(1,("Before ASIO_loadAsioDriver('%s')\n",driverName));
    if ( !ASIO_loadAsioDriver(driverName) ) {
        dmsg(1,("ASIO_OpenAndQueryDeviceInfo could not loadAsioDriver %s\n", driverName));
        return -1;
    }
    dmsg(1,("Before ASIOInit()\n"));
    if( (asioError = ASIOInit(asioDriverInfo)) != ASE_OK ) {
        dmsg(1,("ASIO_OpenAndQueryDeviceInfo: ASIOInit returned %d for %s\n", asioError, driverName));
        return asioError;
    }
    dmsg(1,("Before ASIOGetChannels()\n"));
    if( (asioError = ASIOGetChannels(&driverInfo->numInputChannels, &driverInfo->numOutputChannels) != ASE_OK)) {
        dmsg(1,("ASIO_OpenAndQueryDeviceInfo could not ASIOGetChannels for %s\n", driverName));
        return asioError;
    }

    dmsg(1,("Before ASIOGetBufferSize()\n"));
    if( (asioError = ASIOGetBufferSize(&driverInfo->minBufSize,&driverInfo->maxBufSize,&driverInfo->preferredBufSize,&driverInfo->bufGranularity) != ASE_OK)) {
        dmsg(1,("ASIO_OpenAndQueryDeviceInfo could not ASIOGetBufferSize for %s\n", driverName));
        return asioError;
    }

    dmsg(0,("ASIO_OpenAndQueryDeviceInfo: InputChannels = %d\n", driverInfo->numInputChannels ));
    dmsg(0,("ASIO_OpenAndQueryDeviceInfo: OutputChannels = %d\n", driverInfo->numOutputChannels ));

    /* Loop through the possible sampling rates and check each to see if the device supports it. */
    driverInfo->numSampleRates = 0;
    driverInfo->sampleRates.clear();
    for (int index = 0; index < MAX_NUMSAMPLINGRATES; index++) {
        if (ASIOCanSampleRate(possibleSampleRates[index]) != ASE_NoClock) {
            dmsg(1,("ASIOCanSampleRate: possible sample rate = %d\n", (long)possibleSampleRates[index]));
            driverInfo->sampleRates.push_back( (int)possibleSampleRates[index] );
            driverInfo->numSampleRates++;
        }
    }

    /* get the channel infos for each output channel (including sample format)  */
    for(int i=0 ; i < driverInfo->numOutputChannels ; i++) {
        driverInfo->channelInfos[i].channel = i;
        driverInfo->channelInfos[i].isInput = ASIOFalse;
        ASIOGetChannelInfo(&driverInfo->channelInfos[i]);
        dmsg(1,("channelInfos[%d].type (sampleformat) = %d\n", i, driverInfo->channelInfos[i].type));
    }

    dmsg(1,("ASIO_OpenAndQueryDeviceInfo: driver opened.\n"));
    asioDriverOpened = true;
    return ASE_OK;
}


std::vector<String> getAsioDriverNames() {

    char* names[ASIO_MAX_DEVICE_INFO];
    int numDrivers;

    if(asioDriverListLoaded) {
        dmsg(1,("getAsioDriverNames: ASIO driver list already loaded, doing returning cached list.\n"));
        return asioDriverList;
    }

    /* MUST BE CHECKED : to force fragments loading on Mac */
    ASIO_loadAsioDriver("dummy");

    #if MAC
    numDrivers = asioDrivers->getNumFragments();
    #elif WINDOWS
    numDrivers = asioDrivers->asioGetNumDev();
    #endif

    for (int i = 0 ; i < ASIO_MAX_DEVICE_INFO ; i++) {
        names[i] = new char[32];
        memset(names[i],0,32);
    }

    /* Get names of all available ASIO drivers */
    asioDrivers->getDriverNames(names,ASIO_MAX_DEVICE_INFO);
    dmsg(1,("getAsioDriverNames: numDrivers=%d\n",numDrivers));

    for (int i = 0 ; i < numDrivers ; i++) {
        dmsg(1,("ASIO DRIVERLIST: i=%d  name='%s'\n",i,names[i]));

        #if 1
        asioDriverList.push_back(names[i]);
        #else
        int asioError;
        //  FIXME: we currently try what is the best methode to exclude not connected devices or not working drivers
        // the code below is for testing only, it tried to load each ASIO driver and if it gives an error it is not included
        // in the list of available drivers (asioDriverList)
        if ( ASIO_loadAsioDriver(names[i]) ) {
            if( (asioError = ASIOInit(&MyAsioDriverInfo)) == ASE_OK ) {
                asioDriverList.push_back(names[i]);
            }
            else {
                dmsg(0,("getDriverList: ASIOInit of driver %s gave Error %d ! ignoring it.\n", names[i],asioError));
            }
        }
        else {
            dmsg(0,("getDriverList: load  driver %s failed! ignoring it.\n", names[i]));
        }
        // FIXME: we need to check this ASIOExit is needed (gave a crash on a ASIO ADSP24(WDM) card so we commented it out)
        //ASIOExit();
        #endif
        currentAsioDriverName="";

    }

    for (int i = 0 ; i < ASIO_MAX_DEVICE_INFO ; i++) {
        delete[] names[i];
    }

        dmsg(1,("getAsioDriverNames: returing from function. asioDriverList.size()=%d\n", asioDriverList.size() ));
    asioDriverListLoaded = true;
        return asioDriverList;
}

unsigned long get_sys_reference_time()
{
        // get the system reference time
        #if WINDOWS
                return timeGetTime();
        #elif MAC
                static const double twoRaisedTo32 = 4294967296.;
                UnsignedWide ys;
                Microseconds(&ys);
                double r = ((double)ys.hi * twoRaisedTo32 + (double)ys.lo);
                return (unsigned long)(r / 1000.);
        #endif
}


//----------------------------------------------------------------------------------
// conversion from 64 bit ASIOSample/ASIOTimeStamp to double float
#if NATIVE_INT64
        #define ASIO64toDouble(a)  (a)
#else
        const double twoRaisedTo32 = 4294967296.;
        #define ASIO64toDouble(a)  ((a).lo + (a).hi * twoRaisedTo32)
#endif


ASIOTime* AudioOutputDeviceAsio::bufferSwitchTimeInfo(ASIOTime *timeInfo, long index, ASIOBool processNow)
{

    static long processedSamples = 0;
    // store the timeInfo for later use
    asioDriverInfo.tInfo = *timeInfo;

    // get the time stamp of the buffer, not necessary if no
    // synchronization to other media is required
    if (timeInfo->timeInfo.flags & kSystemTimeValid)
        asioDriverInfo.nanoSeconds = ASIO64toDouble(timeInfo->timeInfo.systemTime);
    else
        asioDriverInfo.nanoSeconds = 0;

    if (timeInfo->timeInfo.flags & kSamplePositionValid)
        asioDriverInfo.samples = ASIO64toDouble(timeInfo->timeInfo.samplePosition);
    else
        asioDriverInfo.samples = 0;

    if (timeInfo->timeCode.flags & kTcValid)
        asioDriverInfo.tcSamples = ASIO64toDouble(timeInfo->timeCode.timeCodeSamples);
    else
        asioDriverInfo.tcSamples = 0;

    // get the system reference time
    asioDriverInfo.sysRefTime = get_sys_reference_time();

        // buffer size in samples
        long buffSize = asioDriverInfo.chosenBufSize;
        int32_t *p;

    //  tell LinuxSampler to  render a fragment of buffSize samples
    GlobalAudioOutputDeviceAsioThisPtr->RenderAudio(buffSize);

        // now write and convert the samples to the ASIO buffer
        for (int i = 0; i < asioDriverInfo.numOutputBuffers; i++)
        {
        // do processing for the outputs only
        switch (asioDriverInfo.channelInfos[i].type)
        {
            case ASIOSTInt16LSB:
                memset (asioDriverInfo.bufferInfos[i].buffers[index], 0, buffSize * 2);
                break;
            case ASIOSTInt24LSB:                // used for 20 bits as well
                memset (asioDriverInfo.bufferInfos[i].buffers[index], 0, buffSize * 3);
                break;
            case ASIOSTInt32LSB:
                p = (int32_t *)asioDriverInfo.bufferInfos[i].buffers[index];
                floatToASIOSTInt32LSB(GlobalAudioOutputDeviceAsioThisPtr->Channels[i]->Buffer(), p, buffSize);
                break;
            case ASIOSTFloat32LSB:              // IEEE 754 32 bit float, as found on Intel x86 architecture
                throw AudioOutputException(String("ASIO Error: ASIOSTFloat32LSB not yet supported! report to LinuxSampler developers.") );
                break;
            case ASIOSTFloat64LSB:              // IEEE 754 64 bit double float, as found on Intel x86 architecture
                throw AudioOutputException(String("ASIO Error: ASIOSTFloat64LSB not yet supported! report to LinuxSampler developers.") );
                break;

            // these are used for 32 bit data buffer, with different alignment of the data inside
            // 32 bit PCI bus systems can more easily used with these
            case ASIOSTInt32LSB16:              // 32 bit data with 18 bit alignment
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32LSB16 not yet supported! report to LinuxSampler developers.") );
                break;
            case ASIOSTInt32LSB18:              // 32 bit data with 18 bit alignment
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32LSB18 not yet supported! report to LinuxSampler developers.") );
                break;
            case ASIOSTInt32LSB20:              // 32 bit data with 20 bit alignment
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32LSB20 not yet supported! report to LinuxSampler developers.") );
                break;
            case ASIOSTInt32LSB24:              // 32 bit data with 24 bit alignment
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32LSB24 not yet supported! report to LinuxSampler developers.") );
                break;
            case ASIOSTInt16MSB:
                throw AudioOutputException(String("ASIO Error: ASIOSTInt16MSB not yet supported! report to LinuxSampler developers.") );
                                break;
                        case ASIOSTInt24MSB:            // used for 20 bits as well
                throw AudioOutputException(String("ASIO Error: ASIOSTInt24MSB not yet supported! report to LinuxSampler developers.") );
                                break;
                        case ASIOSTInt32MSB:
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32MSB not yet supported! report to LinuxSampler developers.") );
                                break;
                        case ASIOSTFloat32MSB:          // IEEE 754 32 bit float, as found on bigendian architecture
                throw AudioOutputException(String("ASIO Error: ASIOSTFloat32MSB not yet supported! report to LinuxSampler developers.") );
                                break;
                        case ASIOSTFloat64MSB:          // IEEE 754 64 bit double float, as found on bigendian architecture
                throw AudioOutputException(String("ASIO Error: ASIOSTFloat64MSB not yet supported! report to LinuxSampler developers.") );
                                break;

                                // these are used for 32 bit data buffer, with different alignment of the data inside
                                // 32 bit PCI bus systems can more easily used with these
                        case ASIOSTInt32MSB16:          // 32 bit data with 18 bit alignment
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32MSB16 not yet supported! report to LinuxSampler developers.") );
                break;
            case ASIOSTInt32MSB18:              // 32 bit data with 18 bit alignment
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32MSB18 not yet supported! report to LinuxSampler developers.") );
                break;
                        case ASIOSTInt32MSB20:          // 32 bit data with 20 bit alignment
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32MSB20 not yet supported! report to LinuxSampler developers.") );
                break;
                        case ASIOSTInt32MSB24:          // 32 bit data with 24 bit alignment
                throw AudioOutputException(String("ASIO Error: ASIOSTInt32MSB24 not yet supported! report to LinuxSampler developers.") );
                                break;
            default:
            throw AudioOutputException(String("ASIO Error: unknown ASIOST sample format. report error.") );
                break;
        }
        }

        // finally if the driver supports the ASIOOutputReady() optimization, do it here, all data are in place
        if (asioDriverInfo.ASIOOutputReadySupported)
                ASIOOutputReady();

    processedSamples += buffSize;
        return 0L;
}

void AudioOutputDeviceAsio::bufferSwitch(long index, ASIOBool processNow)
{
    // the actual processing callback.
    // as this is a "back door" into the bufferSwitchTimeInfo a timeInfo needs to be created
    // though it will only set the timeInfo.samplePosition and timeInfo.systemTime fields and the according flags
    ASIOTime  timeInfo;
    memset (&timeInfo, 0, sizeof (timeInfo));

    // get the time stamp of the buffer, not necessary if no
    // synchronization to other media is required
    if(ASIOGetSamplePosition(&timeInfo.timeInfo.samplePosition, &timeInfo.timeInfo.systemTime) == ASE_OK)
        timeInfo.timeInfo.flags = kSystemTimeValid | kSamplePositionValid;

    bufferSwitchTimeInfo (&timeInfo, index, processNow);
}

void sampleRateChanged(ASIOSampleRate sRate)
{
        // do whatever you need to do if the sample rate changed
        // usually this only happens during external sync.
        // Audio processing is not stopped by the driver, actual sample rate
        // might not have even changed, maybe only the sample rate status of an
        // AES/EBU or S/PDIF digital input at the audio device.
        // You might have to update time/sample related conversion routines, etc.
}

long asioMessages(long selector, long value, void* message, double* opt)
{
    dmsg(1,("asioMessages selector=%d value=%d\n",selector,value));
    // currently the parameters "value", "message" and "opt" are not used.
    long ret = 0;
    switch(selector)
    {
        case kAsioSelectorSupported:
            if(value == kAsioResetRequest
            || value == kAsioEngineVersion
            || value == kAsioResyncRequest
            || value == kAsioLatenciesChanged
            // the following three were added for ASIO 2.0, we don't necessarily have to support them
            || value == kAsioSupportsTimeInfo
            || value == kAsioSupportsTimeCode
            || value == kAsioSupportsInputMonitor)
                ret = 1L;
            break;
        case kAsioResetRequest:
            // defer the task and perform the reset of the driver during the next "safe" situation
            // You cannot reset the driver right now, as this code is called from the driver.
            // Reset the driver is done by completely destruct is. I.e. ASIOStop(), ASIODisposeBuffers(), Destruction
            // Afterwards you initialize the driver again.
            //GlobalAudioOutputDeviceAsioThisPtr->asioDriverInfo.stopped;  // In this sample the processing will just stop
            ret = 1L;
            break;
        case kAsioResyncRequest:
            // This informs the application, that the driver encountered some non fatal data loss.
            // It is used for synchronization purposes of different media.
            // Added mainly to work around the Win16Mutex problems in Windows 95/98 with the
            // Windows Multimedia system, which could loose data because the Mutex was hold too long
            // by another thread.
            // However a driver can issue it in other situations, too.
            ret = 1L;
            break;
        case kAsioLatenciesChanged:
            // This will inform the host application that the drivers were latencies changed.
            // Beware, it this does not mean that the buffer sizes have changed!
            // You might need to update internal delay data.
            ret = 1L;
            break;
        case kAsioEngineVersion:
            // return the supported ASIO version of the host application
            // If a host applications does not implement this selector, ASIO 1.0 is assumed
            // by the driver
            ret = 2L;
            break;
        case kAsioSupportsTimeInfo:
            // informs the driver wether the asioCallbacks.bufferSwitchTimeInfo() callback
            // is supported.
            // For compatibility with ASIO 1.0 drivers the host application should always support
            // the "old" bufferSwitch method, too.
            ret = 1;
            break;
        case kAsioSupportsTimeCode:
            // informs the driver wether application is interested in time code info.
            // If an application does not need to know about time code, the driver has less work
            // to do.
            ret = 0;
            break;
    }
    return ret;
}


// *************** ParameterCard ***************
// *

    AudioOutputDeviceAsio::ParameterCard::ParameterCard() : DeviceCreationParameterString() {
        InitWithDefault(); // use default card
    }

    AudioOutputDeviceAsio::ParameterCard::ParameterCard(String s) throw (Exception) : DeviceCreationParameterString(s) {
    }

    String AudioOutputDeviceAsio::ParameterCard::Description() {
        return "Sound card to be used";
    }

    bool AudioOutputDeviceAsio::ParameterCard::Fix() {
        return true;
    }

    bool AudioOutputDeviceAsio::ParameterCard::Mandatory() {
        return false;
    }

    std::map<String,DeviceCreationParameter*> AudioOutputDeviceAsio::ParameterCard::DependsAsParameters() {
        return std::map<String,DeviceCreationParameter*>(); // no dependencies
    }

    optional<String> AudioOutputDeviceAsio::ParameterCard::DefaultAsString(std::map<String,String> Parameters) {

        std::vector<String> cards = PossibilitiesAsString(Parameters);
        if (cards.empty()) throw Exception("AudioOutputDeviceAsio: Can't find any card");
        dmsg(1,("AudioOutputDeviceAsio::ParameterCard::DefaultAsString='%s'\n",cards[0].c_str() ));
        return cards[0]; // first card by default
    }

    std::vector<String> AudioOutputDeviceAsio::ParameterCard::PossibilitiesAsString(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterCard::PossibilitiesAsString:\n"));
                return getAsioDriverNames();
    }

    void AudioOutputDeviceAsio::ParameterCard::OnSetValue(String s) throw (Exception) {
        // not posssible, as parameter is fix
    }

    String AudioOutputDeviceAsio::ParameterCard::Name() {
        return "CARD";
    }


// *************** ParameterSampleRate ***************
// *

    AudioOutputDeviceAsio::ParameterSampleRate::ParameterSampleRate() : AudioOutputDevice::ParameterSampleRate::ParameterSampleRate() {
    }

    AudioOutputDeviceAsio::ParameterSampleRate::ParameterSampleRate(String s) : AudioOutputDevice::ParameterSampleRate::ParameterSampleRate(s) {
    }

    std::map<String,DeviceCreationParameter*> AudioOutputDeviceAsio::ParameterSampleRate::DependsAsParameters() {
        static ParameterCard card;
        std::map<String,DeviceCreationParameter*> dependencies;
        dependencies[card.Name()] = &card;
        return dependencies;
    }

    optional<int> AudioOutputDeviceAsio::ParameterSampleRate::DefaultAsInt(std::map<String,String> Parameters) {
        if (!Parameters.count("CARD")) {
            dmsg(1,("AudioOutputDeviceAsio::ParameterSampleRate::DefaultAsInt returning optional<int>::nothing  (parameter CARD not supplied)\n"));
            return optional<int>::nothing;
                }

        // return the default samplerate. first try 44100 then 48000,  then the first samplerate found in the list
        ParameterCard card(Parameters["CARD"]);
        if( ASIO_OpenAndQueryDeviceInfo((char *)card.ValueAsString().c_str(), &asioDriverInfo, &MyAsioDriverInfo) != ASE_OK) {
            throw AudioOutputException(String("Error: ASIO Initalization Error") );
        }
        for(int i = 0 ; i < asioDriverInfo.sampleRates.size() ; i++) {
            if(asioDriverInfo.sampleRates[i] == 44100) {
                return 44100;
                dmsg(1,("AudioOutputDeviceAsio::ParameterSampleRate::DefaultAsInt returning 44100\n"));
            }
            if(asioDriverInfo.sampleRates[i] == 48000) {
                dmsg(1,("AudioOutputDeviceAsio::ParameterSampleRate::DefaultAsInt returning 48000\n"));
                return 48000;
            }
        }
        dmsg(1,("AudioOutputDeviceAsio::ParameterSampleRate::DefaultAsInt returning %d\n",asioDriverInfo.sampleRates[0]));
        return asioDriverInfo.sampleRates[0];
    }

        std::vector<int> AudioOutputDeviceAsio::ParameterSampleRate::PossibilitiesAsInt(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterSampleRate::PossibilitiesAsInt\n"));
        if (!Parameters.count("CARD")) {
            dmsg(1,("AudioOutputDeviceAsio::ParameterSampleRate::PossibilitiesAsInt returning empty vector  (parameter CARD not supplied)\n"));
            return std::vector<int>();
        }

        ParameterCard card(Parameters["CARD"]);
        if( ASIO_OpenAndQueryDeviceInfo((char *)card.ValueAsString().c_str(), &asioDriverInfo, &MyAsioDriverInfo) != ASE_OK) {
            throw AudioOutputException(String("Error: ASIO Initalization Error") );
        }

        for(int i=0;i<asioDriverInfo.sampleRates.size();i++) {
            dmsg(1,("AudioOutputDeviceAsio::ParameterSampleRate::PossibilitiesAsInt samplerate[%d]=%d\n",i,asioDriverInfo.sampleRates[i]));
        }

                return asioDriverInfo.sampleRates;
     }


// *************** ParameterChannels ***************
// *

    AudioOutputDeviceAsio::ParameterChannels::ParameterChannels() : AudioOutputDevice::ParameterChannels::ParameterChannels() {
        //InitWithDefault();
        // could not determine default value? ...
        //if (ValueAsInt() == 0) SetValue(2); // ... then (try) a common value
    }

    AudioOutputDeviceAsio::ParameterChannels::ParameterChannels(String s) : AudioOutputDevice::ParameterChannels::ParameterChannels(s) {
    }

    std::map<String,DeviceCreationParameter*> AudioOutputDeviceAsio::ParameterChannels::DependsAsParameters() {
        static ParameterCard card;
        std::map<String,DeviceCreationParameter*> dependencies;
        dependencies[card.Name()] = &card;
        return dependencies;
    }

    optional<int> AudioOutputDeviceAsio::ParameterChannels::DefaultAsInt(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::DefaultAsInt\n"));
        if (!Parameters.count("CARD")) {
            dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::DefaultAsInt returning optional<int>::nothing (CARD parameter not supplied)\n"));
            return optional<int>::nothing;
        }

        ParameterCard card(Parameters["CARD"]);
        if( ASIO_OpenAndQueryDeviceInfo((char *)card.ValueAsString().c_str(), &asioDriverInfo, &MyAsioDriverInfo) != ASE_OK) {
            throw AudioOutputException(String("Error: ASIO Initialization Error") );
        }
        dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::DefaultAsInt returning %d\n",asioDriverInfo.numOutputChannels));
        return asioDriverInfo.numOutputChannels;
    }

    optional<int> AudioOutputDeviceAsio::ParameterChannels::RangeMinAsInt(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::RangeMinAsInt!\n"));
        if (!Parameters.count("CARD")) {
            dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::RangeMinAsInt returning optional<int>::nothing (CARD parameter not supplied)\n"));
            return optional<int>::nothing;
        }
        dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::RangeMinAsInt returning 1\n"));
        return 1;
    }

    optional<int> AudioOutputDeviceAsio::ParameterChannels::RangeMaxAsInt(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::RangeMaxAsInt!\n"));
        if (!Parameters.count("CARD")) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::RangeMaxAsInt returning optional<int>::nothing (CARD parameter not supplied)\n"));
            return optional<int>::nothing;
        }

        ParameterCard card(Parameters["CARD"]);
        if( ASIO_OpenAndQueryDeviceInfo((char *)card.ValueAsString().c_str(), &asioDriverInfo, &MyAsioDriverInfo) != ASE_OK) {
            throw AudioOutputException(String("Error: ASIO Init Error") );
        }
        dmsg(1,("AudioOutputDeviceAsio::ParameterChannels::RangeMaxAsInt returning %d\n",asioDriverInfo.numOutputChannels));
        return asioDriverInfo.numOutputChannels;
    }


// *************** ParameterFragmentSize ***************
// *

    AudioOutputDeviceAsio::ParameterFragmentSize::ParameterFragmentSize() : DeviceCreationParameterInt() {
        InitWithDefault();
    }

    AudioOutputDeviceAsio::ParameterFragmentSize::ParameterFragmentSize(String s) throw (Exception) : DeviceCreationParameterInt(s) {
    }

    String AudioOutputDeviceAsio::ParameterFragmentSize::Description() {
        return "Size of each buffer fragment";
    }

    bool AudioOutputDeviceAsio::ParameterFragmentSize::Fix() {
        return true;
    }

    bool AudioOutputDeviceAsio::ParameterFragmentSize::Mandatory() {
        return false;
    }

    std::map<String,DeviceCreationParameter*> AudioOutputDeviceAsio::ParameterFragmentSize::DependsAsParameters() {
        static ParameterCard card;
        std::map<String,DeviceCreationParameter*> dependencies;
        dependencies[card.Name()] = &card;
        return dependencies;
    }

    optional<int> AudioOutputDeviceAsio::ParameterFragmentSize::DefaultAsInt(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::DefaultAsInt!\n"));
        if (!Parameters.count("CARD")) {
            dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::DefaultAsInt returning optional<int>::nothing (no CARD parameter supplied\n"));
            return optional<int>::nothing;
        }

        ParameterCard card(Parameters["CARD"]);
        if( ASIO_OpenAndQueryDeviceInfo((char *)card.ValueAsString().c_str(), &asioDriverInfo, &MyAsioDriverInfo) != ASE_OK) {
            throw AudioOutputException(String("Error: ASIO Initialization Error") );
        }
        dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::DefaultAsInt returning %d\n",asioDriverInfo.preferredBufSize));
        return asioDriverInfo.preferredBufSize;
    }

    optional<int> AudioOutputDeviceAsio::ParameterFragmentSize::RangeMinAsInt(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::RangeMinAsInt!\n"));
        if (!Parameters.count("CARD")) {
            dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::RangeMinAsInt returning optional<int>::nothing (no CARD parameter supplied\n"));
            return optional<int>::nothing;
        }

        ParameterCard card(Parameters["CARD"]);
        if( ASIO_OpenAndQueryDeviceInfo((char *)card.ValueAsString().c_str(), &asioDriverInfo, &MyAsioDriverInfo) != ASE_OK) {
            throw AudioOutputException(String("Error: ASIO Initalization Error") );
        }
        dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::RangeMinAsInt returning %d\n",asioDriverInfo.minBufSize));
        return asioDriverInfo.minBufSize;
    }

    optional<int> AudioOutputDeviceAsio::ParameterFragmentSize::RangeMaxAsInt(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::RangeMaxAsInt!\n"));
        if (!Parameters.count("CARD")) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::RangeMaxAsInt returning optional<int>::nothing (no CARD parameter supplied\n"));
            return optional<int>::nothing;
        }

        ParameterCard card(Parameters["CARD"]);
        if( ASIO_OpenAndQueryDeviceInfo((char *)card.ValueAsString().c_str(), &asioDriverInfo, &MyAsioDriverInfo) != ASE_OK) {
            throw AudioOutputException(String("Error: ASIO Initialization Error") );
        }
        dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::RangeMaxAsInt returning %d\n",asioDriverInfo.maxBufSize));
        return asioDriverInfo.maxBufSize;
    }

    std::vector<int> AudioOutputDeviceAsio::ParameterFragmentSize::PossibilitiesAsInt(std::map<String,String> Parameters) {
        dmsg(1,("AudioOutputDeviceAsio::ParameterFragmentSize::PossibilitiesAsInt!\n"));
        return std::vector<int>();
    }

    void AudioOutputDeviceAsio::ParameterFragmentSize::OnSetValue(int i) throw (Exception) {
        // not posssible, as parameter is fix
    }

    String AudioOutputDeviceAsio::ParameterFragmentSize::Name() {
        return "FRAGMENTSIZE";
    }


// *************** AudioOutputDeviceAsio ***************
// *

    /**
      * Create and initialize Asio audio output device with given parameters.
      *
      * @param Parameters - optional parameters
      * @throws AudioOutputException  if output device cannot be opened
      */
    AudioOutputDeviceAsio::AudioOutputDeviceAsio(std::map<String,DeviceCreationParameter*> Parameters) : AudioOutputDevice(Parameters) {
        if(AudioOutputDeviceAsioInstantiated) throw Exception("AudioOutputDeviceAsio: Sorry, only one ASIO card at time can be opened");
        AudioOutputDeviceAsioInstantiated = true;
        asioDriverOpened = false;
        this->uiAsioChannels = ((DeviceCreationParameterInt*)Parameters["CHANNELS"])->ValueAsInt();
        this->uiSamplerate   = ((DeviceCreationParameterInt*)Parameters["SAMPLERATE"])->ValueAsInt();
        this->FragmentSize   = ((DeviceCreationParameterInt*)Parameters["FRAGMENTSIZE"])->ValueAsInt();
        String Card          = ((DeviceCreationParameterString*)Parameters["CARD"])->ValueAsString();


                dmsg(1,("AudioOutputDeviceAsio::AudioOutputDeviceAsio constructor\n"));

                asioIsPlaying = false;

        ASIO_OpenAndQueryDeviceInfo((char *)Card.c_str(), &asioDriverInfo, &MyAsioDriverInfo);
        dmsg(1,("AudioOutputDeviceAsio::AudioOutputDeviceAsio: after ASIO_OpenAndQueryDeviceInfo\n"));

        if( ASIOSetSampleRate(uiSamplerate) != ASE_OK ) {
            throw AudioOutputException(String("Error: ASIOSetSampleRate: cannot set samplerate. ") );
        }
        dmsg(1,("AudioOutputDeviceAsio::AudioOutputDeviceAsio: after ASIOSetSampleRate\n"));

        if(ASIOOutputReady() == ASE_OK) asioDriverInfo.ASIOOutputReadySupported = true;
        else asioDriverInfo.ASIOOutputReadySupported = false;
        dmsg(1,("AudioOutputDeviceAsio::AudioOutputDeviceAsio: after ASIOOutputReady\n"));

        asioDriverInfo.numInputBuffers = 0;
        asioDriverInfo.numOutputBuffers = uiAsioChannels;
        asioDriverInfo.chosenBufSize = FragmentSize;

        for( int i = 0 ; i < uiAsioChannels ; i++) {
            asioDriverInfo.bufferInfos[i].isInput = ASIOFalse;
            asioDriverInfo.bufferInfos[i].channelNum = i;
        }

        asioCallbacks.bufferSwitch = &bufferSwitch;
        asioCallbacks.sampleRateDidChange = &sampleRateChanged;
        asioCallbacks.asioMessage = &asioMessages;
        asioCallbacks.bufferSwitchTimeInfo = &bufferSwitchTimeInfo;

        if ( ASIOCreateBuffers(asioDriverInfo.bufferInfos, asioDriverInfo.numOutputBuffers, asioDriverInfo.chosenBufSize = FragmentSize, &asioCallbacks) != ASE_OK ){
            throw AudioOutputException(String("AudioOutputDeviceAsio: Error: ASIOCreateBuffers failed.") );
        }
        dmsg(1,("AudioOutputDeviceAsio::AudioOutputDeviceAsio: after ASIOCreateBuffers\n"));

        // create audio channels for this audio device to which the sampler engines can write to
        for (int i = 0; i < uiAsioChannels; i++) this->Channels.push_back(new AudioChannel(i, FragmentSize));

        // FIXME: temporary global variable used to store the this pointer for the ASIO callbacks wanting to access the AudioOutputDeviceAsio methods
        GlobalAudioOutputDeviceAsioThisPtr = this;

        if (((DeviceCreationParameterBool*)Parameters["ACTIVE"])->ValueAsBool()) {
            Play();
        }
    }

    AudioOutputDeviceAsio::~AudioOutputDeviceAsio() {
        ASIOExit();
        asioDriverOpened = false;
        AudioOutputDeviceAsioInstantiated = false;
    }

    void AudioOutputDeviceAsio::Play() {
        dmsg(1,("AudioOutputDeviceAsio::Play() !\n"));
        if ( ASIOStart() != ASE_OK ){
                    asioIsPlaying = false;
            throw AudioOutputException(String("AudioOutputDeviceAsio: Error: ASIOStart failed.") );
        }
                else asioIsPlaying = true;
    }

    bool AudioOutputDeviceAsio::IsPlaying() {
        return asioIsPlaying;
    }

    void AudioOutputDeviceAsio::Stop() {
        dmsg(1,("AudioOutputDeviceAsio::Stop() !\n"));
        ASIOStop();
        asioIsPlaying = false;
    }

    AudioChannel* AudioOutputDeviceAsio::CreateChannel(uint ChannelNr) {
        dmsg(1,("AudioOutputDeviceAsio::CreateChannel value=%d  uiAsioChannels=%d\n",ChannelNr,uiAsioChannels));
        // just create a mix channel
        return new AudioChannel(ChannelNr, Channel(ChannelNr % uiAsioChannels));
    }

    uint AudioOutputDeviceAsio::MaxSamplesPerCycle() {
        dmsg(3,("AudioOutputDeviceAsio::MaxSamplesPerCycle value=%d\n",FragmentSize));
        return FragmentSize;
    }

    uint AudioOutputDeviceAsio::SampleRate() {
        dmsg(1,("AudioOutputDeviceAsio::SampleRate value=%d\n",uiSamplerate)); fflush(stdout);
        return uiSamplerate;
    }

    String AudioOutputDeviceAsio::Name() {
        return "ASIO";
    }

    String AudioOutputDeviceAsio::Driver() {
        return Name();
    }

    String AudioOutputDeviceAsio::Description() {
        return "Audio Streaming Input Output 2.2";
    }

    String AudioOutputDeviceAsio::Version() {
       String s = "$Revision: 1.2 $";
       return s.substr(11, s.size() - 13); // cut dollar signs, spaces and CVS macro keyword
    }

} // namespace LinuxSampler