问带音量调节的麦克风语音采集接口

EN

class VOICEIO_EXPORT VoiceIOAdapter : public QIODevice
{
    Q_OBJECT

public:
    VoiceIOAdapter(QObject *parent,QIODevice* dev);
    VoiceIOAdapter(QObject *parent);
    ~VoiceIOAdapter();
    void setUnderlyingDevice(QIODevice* dev);
    QIODevice* getUnderlyingDevice() const;
        ... /*some qiodevice virtual functions reimplemented*/
        ...
    float getOutVolume()const;
    float getInVolume() const;
public slots:
    void setOutVolume(float);
    void setInVolume(float);
protected:
    QIODevice* underlyingDevice;
    virtual qint64  readData ( char * data, qint64 maxSize );
    virtual qint64  writeData ( const char * data, qint64 maxSize );
    void applyVolume(float value, QByteArray& input);
    float outVolume;//1
    float inVolume;//1
};


void VoiceIOAdapter::applyVolume(float value, QByteArray& input)
{
    Q_ASSERT(!(input.size()%2)); //SHORT,Signed,LE
    qint16* data=reinterpret_cast<qint16*>(input.data());
    qint32 tmp;
    for(int i=0;i<input.size()/2;i++)
    {
        tmp=qint32(float(data[i])*value);
        if(tmp>std::numeric_limits<qint16>::max())
        {
            tmp=std::numeric_limits<qint16>::max();
        }
        else if (tmp<std::numeric_limits<qint16>::min())
        {
            tmp=std::numeric_limits<qint16>::min();
        }
        data[i]=tmp;
    }
}

qint64  VoiceIOAdapter::readData ( char * data, qint64 maxSize )
{
    if(!underlyingDevice)
    {
        return -1;
    }
        QByteArray decoded(maxSize ,0);
    qint64 result=underlyingDevice->read(decoded.data(),maxSize);
    if(result>0)
    {
                decoded.resize(result);
        applyVolume(inVolume,decoded);
        memcpy(data,decoded.data(),decoded.size());
    }
    return result;
}

qint64  VoiceIOAdapter::writeData ( const char * data, qint64 maxSize )
{
    if(!underlyingDevice)
    {
        return -1;
    }
    QByteArray encoded(data,maxSize);
    applyVolume(outVolume,encoded);
    qint64 result=underlyingDevice->write(encoded.data(),maxSize );
    return result;
}