Window.h

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///
///  Window.h -- specification of the various function window classes
/// See the copyright notice and acknowledgment of authors in the file COPYRIGHT
///
/// Helper class for other classes that need a signal to be windowed. For example, to perform an FFT
/// usually is better to apply a window function to the signal to get beter results.
/// Usage (two ways to be used):
///     a) Instantiate a window object (for example Window myWindow(512, 1);) and then call the window()
///         function to get a pointer to the window buffer. 
///         or...
///     b) call the nextBuffer on the window, so it fills a buffer with itself, wraping around if the buffer
///         passed is larger.
///
/// The size should be specified in samples.
/// 
/// TODO:
///     a) Add more window types.
///

#ifndef CSL_WINDOW_H
#define CSL_WINDOW_H

#include "CSL_Core.h"

namespace csl {

/// Window; The superclass of all other window function classes in CSL.
/// Subclasses need only to implement the fillWindow(); and the Constructors.

class Window : public UnitGenerator {
public:             // Constructors:
    Window();       ///< Creates a window using the default Gestalt size and a gain of 1;
                    ///< Creates a window (hann) with the specified size and gain (gain is optional).
    Window(unsigned windowSize, float gain = 1); 
    ~Window();      ///< clean-up . . . free the allocated buffer that held the window data.

    void setSize(unsigned windowSize);  ///< Set the number of samples the window spans.
    void setGain(float gain);               ///< Set the gain to which the window should be normalized.
    SampleBuffer window() { return mWindowBuffer.buffer(0); }; ///< Returns a pointer to the window data.

    void nextBuffer(Buffer &outputBuffer, unsigned outBufNum) throw (CException);
    void dump();        ///< Print some info about the window.
    
protected:
    Buffer mWindowBuffer;       ///< used to store the window
    unsigned mWindowBufferPos;  ///< where am I in the window buffer
    unsigned mWindowSize;       ///< length in samples of the window
    float mGain;                    ///< gain for the window

    virtual void fillWindow();      ///< subclasses override this to fill the buffer with corresponding function.
};

/// RectangularWindow:A rectangular window has all values set to the Gain value, or by default to 1.

class RectangularWindow : public Window {
public:
    RectangularWindow() : Window() { }
    RectangularWindow(unsigned windowSize) : Window(windowSize) { }
    RectangularWindow(unsigned windowSize, float gain) : Window(windowSize, gain) { }
    ~RectangularWindow() { }
    
protected:
    void fillWindow();
};

/// TriangularWindow:A triangularWindow window.

class TriangularWindow : public Window {
public:
    TriangularWindow() : Window() { }
    TriangularWindow(unsigned windowSize) : Window(windowSize) { }
    TriangularWindow(unsigned windowSize, float gain) : Window(windowSize, gain) { }
    ~TriangularWindow() { }
    
protected:
    void fillWindow();
};

/// HammingWindow: Belongs to the familly of cosine window functions. 

class HammingWindow : public Window {
public:

    HammingWindow() : Window() { }
    HammingWindow(unsigned windowSize) : Window(windowSize) { }
    HammingWindow(unsigned windowSize, float gain) : Window(windowSize, gain) { }
    ~HammingWindow() { }

protected:
    void fillWindow();
};

/// HannWindow

class HannWindow : public Window {
public:
    HannWindow() : Window() { }
    HannWindow(unsigned windowSize) : Window(windowSize) { }
    HannWindow(unsigned windowSize, float gain) : Window(windowSize, gain) { }
    ~HannWindow() { }
    
protected:
    void fillWindow();
};

/// BlackmanWindow

class BlackmanWindow : public Window {
public:
    BlackmanWindow() : Window() { }
    BlackmanWindow(unsigned windowSize) : Window(windowSize) { }
    BlackmanWindow(unsigned windowSize, float gain) : Window(windowSize, gain) { }
    ~BlackmanWindow() { }
    
protected:
    void fillWindow();
};

/// BlackmanHarrisWindow

class BlackmanHarrisWindow : public Window {
public:
    BlackmanHarrisWindow() : Window() { }
    BlackmanHarrisWindow(unsigned windowSize) : Window(windowSize) { }
    BlackmanHarrisWindow(unsigned windowSize, float gain) : Window(windowSize, gain) { }
    ~BlackmanHarrisWindow() { }
    
protected:
    void fillWindow();
};

/// WelchWindow: This is basically an equal-power curve.

class WelchWindow : public Window {
public:
    WelchWindow() : Window() { }
    WelchWindow(unsigned windowSize) : Window(windowSize) { }
    WelchWindow(unsigned windowSize, float gain) : Window(windowSize, gain) { }
    ~WelchWindow() { }
    
protected:
    void fillWindow();
};

}  // end of namespace

#endif