108 lines
2.6 KiB
C
108 lines
2.6 KiB
C
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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
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/*
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Rubber Band
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An audio time-stretching and pitch-shifting library.
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Copyright 2007-2010 Chris Cannam.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version. See the file
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COPYING included with this distribution for more information.
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*/
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#ifndef _RUBBERBAND_SINC_WINDOW_H_
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#define _RUBBERBAND_SINC_WINDOW_H_
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#include <cmath>
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#include <iostream>
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#include <cstdlib>
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#include <map>
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#include "system/sysutils.h"
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#include "system/VectorOps.h"
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#include "system/Allocators.h"
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namespace RubberBand {
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template <typename T>
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class SincWindow
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{
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public:
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/**
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* Construct a sinc windower which produces a window of the given
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* size containing the values of sinc(x) with x=0 at the centre,
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* such that the distance from -pi to pi (the point at which the
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* sinc function first crosses zero, for negative and positive
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* arguments respectively) is p samples.
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*/
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SincWindow(int size, int p) : m_size(size), m_p(p) { encache(); }
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SincWindow(const SincWindow &w) : m_size(w.m_size), m_p(w.m_p) { encache(); }
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SincWindow &operator=(const SincWindow &w) {
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if (&w == this) return *this;
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m_size = w.m_size;
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m_p = w.m_p;
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encache();
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return *this;
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}
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virtual ~SincWindow() { delete[] m_cache; }
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inline void cut(T *const R__ block) const {
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v_multiply(block, m_cache, m_size);
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}
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inline void cut(const T *const R__ src, T *const R__ dst) const {
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v_multiply(dst, src, m_cache, m_size);
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}
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inline void add(T *const R__ dst, T scale) const {
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v_add_with_gain(dst, m_cache, m_size, scale);
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}
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inline T getArea() const { return m_area; }
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inline T getValue(int i) const { return m_cache[i]; }
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inline int getSize() const { return m_size; }
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inline int getP() const { return m_p; }
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protected:
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int m_size;
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int m_p;
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T *R__ m_cache;
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T m_area;
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void encache();
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};
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template <typename T>
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void SincWindow<T>::encache()
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{
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const int n = m_size;
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T *mult = allocate<T>(n);
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v_set(mult, T(1.0), n);
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int i;
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for (i = 0; i < n; ++i) {
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T extent = T(n)/2.;
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T arg = (T(i) - extent) * (2. * M_PI) / m_p;
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if (arg != 0.) {
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mult[i] *= sin(arg) / arg;
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}
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}
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m_cache = mult;
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m_area = 0;
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for (i = 0; i < n; ++i) {
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std::cout << i << ":" << m_cache[i] << " ";
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m_area += m_cache[i];
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}
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std::cout << std::endl;
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m_area /= n;
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}
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}
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#endif
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