Chris@366: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@366: /*
Chris@366:     Constant-Q library
Chris@366:     Copyright (c) 2013-2014 Queen Mary, University of London
Chris@366: 
Chris@366:     Permission is hereby granted, free of charge, to any person
Chris@366:     obtaining a copy of this software and associated documentation
Chris@366:     files (the "Software"), to deal in the Software without
Chris@366:     restriction, including without limitation the rights to use, copy,
Chris@366:     modify, merge, publish, distribute, sublicense, and/or sell copies
Chris@366:     of the Software, and to permit persons to whom the Software is
Chris@366:     furnished to do so, subject to the following conditions:
Chris@366: 
Chris@366:     The above copyright notice and this permission notice shall be
Chris@366:     included in all copies or substantial portions of the Software.
Chris@366: 
Chris@366:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
Chris@366:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
Chris@366:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
Chris@366:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
Chris@366:     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
Chris@366:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
Chris@366:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Chris@366: 
Chris@366:     Except as contained in this notice, the names of the Centre for
Chris@366:     Digital Music; Queen Mary, University of London; and Chris Cannam
Chris@366:     shall not be used in advertising or otherwise to promote the sale,
Chris@366:     use or other dealings in this Software without prior written
Chris@366:     authorization.
Chris@366: */
Chris@366: 
Chris@366: #ifndef WINDOW_H
Chris@366: #define WINDOW_H
Chris@366: 
Chris@366: #include <cmath>
Chris@366: #include <iostream>
Chris@366: #include <map>
Chris@366: #include <vector>
Chris@366: 
Chris@366: #include "pi.h"
Chris@366: 
Chris@366: enum WindowType {
Chris@366:     RectangularWindow,
Chris@366:     BartlettWindow,
Chris@366:     HammingWindow,
Chris@366:     HanningWindow,
Chris@366:     BlackmanWindow,
Chris@366:     BlackmanHarrisWindow,
Chris@366: 
Chris@366:     FirstWindow = RectangularWindow,
Chris@366:     LastWindow = BlackmanHarrisWindow
Chris@366: };
Chris@366: 
Chris@366: /**
Chris@366:  * Various shaped windows for sample frame conditioning, including
Chris@366:  * cosine windows (Hann etc) and triangular and rectangular windows.
Chris@366:  */
Chris@366: template <typename T>
Chris@366: class Window
Chris@366: {
Chris@366: public:
Chris@366:     /**
Chris@366:      * Construct a windower of the given type and size. 
Chris@366:      *
Chris@366:      * Note that the cosine windows are periodic by design, rather
Chris@366:      * than symmetrical. (A window of size N is equivalent to a
Chris@366:      * symmetrical window of size N+1 with the final element missing.)
Chris@366:      */
Chris@366:     Window(WindowType type, int size) : m_type(type), m_size(size) { encache(); }
Chris@366:     Window(const Window &w) : m_type(w.m_type), m_size(w.m_size) { encache(); }
Chris@366:     Window &operator=(const Window &w) {
Chris@366: 	if (&w == this) return *this;
Chris@366: 	m_type = w.m_type;
Chris@366: 	m_size = w.m_size;
Chris@366: 	encache();
Chris@366: 	return *this;
Chris@366:     }
Chris@366:     virtual ~Window() { delete[] m_cache; }
Chris@366:     
Chris@366:     void cut(T *src) const { cut(src, src); }
Chris@366:     void cut(const T *src, T *dst) const {
Chris@366: 	for (int i = 0; i < m_size; ++i) dst[i] = src[i] * m_cache[i];
Chris@366:     }
Chris@366: 
Chris@366:     WindowType getType() const { return m_type; }
Chris@366:     int getSize() const { return m_size; }
Chris@366: 
Chris@366:     std::vector<T> getWindowData() const {
Chris@366:         std::vector<T> d;
Chris@366:         for (int i = 0; i < m_size; ++i) {
Chris@366:             d.push_back(m_cache[i]);
Chris@366:         }
Chris@366:         return d;
Chris@366:     }
Chris@366: 
Chris@366: protected:
Chris@366:     WindowType m_type;
Chris@366:     int m_size;
Chris@366:     T *m_cache;
Chris@366:     
Chris@366:     void encache();
Chris@366: };
Chris@366: 
Chris@366: template <typename T>
Chris@366: void Window<T>::encache()
Chris@366: {
Chris@366:     int n = m_size;
Chris@366:     T *mult = new T[n];
Chris@366:     int i;
Chris@366:     for (i = 0; i < n; ++i) mult[i] = 1.0;
Chris@366: 
Chris@366:     switch (m_type) {
Chris@366: 		
Chris@366:     case RectangularWindow:
Chris@366:         for (i = 0; i < n; ++i) {
Chris@366:             mult[i] = mult[i] * 0.5;
Chris@366: 	}
Chris@366: 	break;
Chris@366: 	    
Chris@366:     case BartlettWindow:
Chris@366:         if (n == 2) {
Chris@366:             mult[0] = mult[1] = 0; // "matlab compatible"
Chris@366:         } else if (n == 3) {
Chris@366:             mult[0] = 0;
Chris@366:             mult[1] = mult[2] = 2./3.;
Chris@366:         } else if (n > 3) {
Chris@366:             for (i = 0; i < n/2; ++i) {
Chris@366:                 mult[i] = mult[i] * (i / T(n/2));
Chris@366:                 mult[i + n - n/2] = mult[i + n - n/2] * (1.0 - (i / T(n/2)));
Chris@366:             }
Chris@366: 	}
Chris@366: 	break;
Chris@366: 	    
Chris@366:     case HammingWindow:
Chris@366:         if (n > 1) {
Chris@366:             for (i = 0; i < n; ++i) {
Chris@366:                 mult[i] = mult[i] * (0.54 - 0.46 * cos(2 * M_PI * i / n));
Chris@366:             }
Chris@366: 	}
Chris@366: 	break;
Chris@366: 	    
Chris@366:     case HanningWindow:
Chris@366:         if (n > 1) {
Chris@366:             for (i = 0; i < n; ++i) {
Chris@366:                 mult[i] = mult[i] * (0.50 - 0.50 * cos(2 * M_PI * i / n));
Chris@366:             }
Chris@366: 	}
Chris@366: 	break;
Chris@366: 	    
Chris@366:     case BlackmanWindow:
Chris@366:         if (n > 1) {
Chris@366:             for (i = 0; i < n; ++i) {
Chris@366:                 mult[i] = mult[i] * (0.42 - 0.50 * cos(2 * M_PI * i / n)
Chris@366:                                      + 0.08 * cos(4 * M_PI * i / n));
Chris@366:             }
Chris@366: 	}
Chris@366: 	break;
Chris@366: 	    
Chris@366:     case BlackmanHarrisWindow:
Chris@366:         if (n > 1) {
Chris@366:             for (i = 0; i < n; ++i) {
Chris@366:                 mult[i] = mult[i] * (0.35875
Chris@366:                                      - 0.48829 * cos(2 * M_PI * i / n)
Chris@366:                                      + 0.14128 * cos(4 * M_PI * i / n)
Chris@366:                                      - 0.01168 * cos(6 * M_PI * i / n));
Chris@366:             }
Chris@366: 	}
Chris@366: 	break;
Chris@366:     }
Chris@366: 	   
Chris@366:     m_cache = mult;
Chris@366: }
Chris@366: 
Chris@366: #endif