view src/dsp/SincWindow.h @ 179:433e3aac9e52

Add pi.h. Let's stop messing around with platform-specific defines

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
/*
    Constant-Q library
    Copyright (c) 2013-2014 Queen Mary, University of London

    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
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    modify, merge, publish, distribute, sublicense, and/or sell copies
    of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Except as contained in this notice, the names of the Centre for
    Digital Music; Queen Mary, University of London; and Chris Cannam
    shall not be used in advertising or otherwise to promote the sale,
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*/

#ifndef SINC_WINDOW_H
#define SINC_WINDOW_H

#include <vector>

#include "pi.h"

/**
 * A window containing values of the sinc function, i.e. sin(x)/x with
 * sinc(0) == 1, with x == 0 at the centre.
 */
class SincWindow
{
public:
    /**
     * Construct a windower of the given length, containing the values
     * of sinc(x) with x=0 in the middle, i.e. at sample (length-1)/2
     * for odd or (length/2)+1 for even length, such that the distance
     * from -pi to pi (the nearest zero crossings either side of the
     * peak) is p samples.
     */
    SincWindow(int length, double p) : m_length(length), m_p(p) { init(); }

    int getLength() const {
	return m_length;
    }

    const double *getWindow() const { 
	return m_window.data();
    }

    void cut(double *src) const { 
	cut(src, src); 
    }

    void cut(const double *src, double *dst) const {
	for (int i = 0; i < m_length; ++i) {
	    dst[i] = src[i] * m_window[i];
	}
    }

private:
    int m_length;
    double m_p;
    std::vector<double> m_window;

    void init();
};

#endif