Qt Reference Documentation

utils.h Example File

demos/spectrum/app/utils.h
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 #ifndef UTILS_H
 #define UTILS_H

 #include <QtCore/qglobal.h>
 #include <QDebug>

 QT_FORWARD_DECLARE_CLASS(QAudioFormat)

 //-----------------------------------------------------------------------------
 // Miscellaneous utility functions
 //-----------------------------------------------------------------------------

 qint64 audioDuration(const QAudioFormat &format, qint64 bytes);
 qint64 audioLength(const QAudioFormat &format, qint64 microSeconds);

 QString formatToString(const QAudioFormat &format);

 qreal nyquistFrequency(const QAudioFormat &format);

 // Scale PCM value to [-1.0, 1.0]
 qreal pcmToReal(qint16 pcm);

 // Scale real value in [-1.0, 1.0] to PCM
 qint16 realToPcm(qreal real);

 // Check whether the audio format is PCM
 bool isPCM(const QAudioFormat &format);

 // Check whether the audio format is signed, little-endian, 16-bit PCM
 bool isPCMS16LE(const QAudioFormat &format);

 // Compile-time calculation of powers of two

 template<int N> class PowerOfTwo
 { public: static const int Result = PowerOfTwo<N-1>::Result * 2; };

 template<> class PowerOfTwo<0>
 { public: static const int Result = 1; };

 //-----------------------------------------------------------------------------
 // Debug output
 //-----------------------------------------------------------------------------

 class NullDebug
 {
 public:
     template <typename T>
     NullDebug& operator<<(const T&) { return *this; }
 };

 inline NullDebug nullDebug() { return NullDebug(); }

 #ifdef LOG_ENGINE
 #   define ENGINE_DEBUG qDebug()
 #else
 #   define ENGINE_DEBUG nullDebug()
 #endif

 #ifdef LOG_SPECTRUMANALYSER
 #   define SPECTRUMANALYSER_DEBUG qDebug()
 #else
 #   define SPECTRUMANALYSER_DEBUG nullDebug()
 #endif

 #ifdef LOG_WAVEFORM
 #   define WAVEFORM_DEBUG qDebug()
 #else
 #   define WAVEFORM_DEBUG nullDebug()
 #endif

 #endif // UTILS_H
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