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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
Vamp
An API for audio analysis and feature extraction plugins.
Centre for Digital Music, Queen Mary, University of London.
Copyright 2006-2011 Chris Cannam and QMUL.
Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use, copy,
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 AUTHORS BE LIABLE FOR
ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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,
use or other dealings in this Software without prior written
authorization.
*/
#ifndef _WINDOW_H_
#define _WINDOW_H_
#include <vamp-hostsdk/hostguard.h>
#include <cmath>
#include <cstdlib>
_VAMP_SDK_HOSTSPACE_BEGIN(Window.h)
template <typename T>
class Window
{
public:
enum WindowType {
RectangularWindow,
BartlettWindow,
HammingWindow,
HanningWindow,
BlackmanWindow,
NuttallWindow,
BlackmanHarrisWindow
};
/**
* Construct a windower of the given type.
*/
Window(WindowType type, size_t size) : m_type(type), m_size(size) { encache(); }
Window(const Window &w) : m_type(w.m_type), m_size(w.m_size) { encache(); }
Window &operator=(const Window &w) {
if (&w == this) return *this;
m_type = w.m_type;
m_size = w.m_size;
encache();
return *this;
}
virtual ~Window() { delete[] m_cache; }
void cut(T *src) const { cut(src, src); }
void cut(T *src, T *dst) const {
for (size_t i = 0; i < m_size; ++i) dst[i] = src[i] * m_cache[i];
}
template <typename T0>
void cut(T0 *src, T *dst) const {
for (size_t i = 0; i < m_size; ++i) dst[i] = src[i] * m_cache[i];
}
T getArea() { return m_area; }
T getValue(size_t i) { return m_cache[i]; }
WindowType getType() const { return m_type; }
size_t getSize() const { return m_size; }
protected:
WindowType m_type;
size_t m_size;
T *m_cache;
T m_area;
void encache();
void cosinewin(T *, T, T, T, T);
};
template <typename T>
void Window<T>::encache()
{
int n = int(m_size);
T *mult = new T[n];
int i;
for (i = 0; i < n; ++i) mult[i] = 1.0;
switch (m_type) {
case RectangularWindow:
for (i = 0; i < n; ++i) {
mult[i] *= 0.5;
}
break;
case BartlettWindow:
for (i = 0; i < n/2; ++i) {
mult[i] *= (i / T(n/2));
mult[i + n/2] *= (1.0 - (i / T(n/2)));
}
break;
case HammingWindow:
cosinewin(mult, 0.54, 0.46, 0.0, 0.0);
break;
case HanningWindow:
cosinewin(mult, 0.50, 0.50, 0.0, 0.0);
break;
case BlackmanWindow:
cosinewin(mult, 0.42, 0.50, 0.08, 0.0);
break;
case NuttallWindow:
cosinewin(mult, 0.3635819, 0.4891775, 0.1365995, 0.0106411);
break;
case BlackmanHarrisWindow:
cosinewin(mult, 0.35875, 0.48829, 0.14128, 0.01168);
break;
}
m_cache = mult;
m_area = 0;
for (int i = 0; i < n; ++i) {
m_area += m_cache[i];
}
m_area /= n;
}
template <typename T>
void Window<T>::cosinewin(T *mult, T a0, T a1, T a2, T a3)
{
int n = int(m_size);
for (int i = 0; i < n; ++i) {
mult[i] *= (a0
- a1 * cos((2 * M_PI * i) / n)
+ a2 * cos((4 * M_PI * i) / n)
- a3 * cos((6 * M_PI * i) / n));
}
}
_VAMP_SDK_HOSTSPACE_END(Window.h)
#endif
|
