comparison base/SincWindow.cpp @ 126:7669b3aa3bc9

Add sinc

+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    QM DSP library
+    Centre for Digital Music, Queen Mary, University of London.
+ 
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#include "SincWindow.h"
+
+#include <cmath>
+
+void
+SincWindow::init()
+{
+    if (m_length < 1) {
+	return;
+    } else if (m_length < 2) {
+	m_window.push_back(1);
+	return;
+    } else {
+
+	int n0 = (m_length % 2 == 0 ? m_length/2 : (m_length - 1)/2);
+	int n1 = (m_length % 2 == 0 ? m_length/2 : (m_length + 1)/2);
+	double m = 2 * M_PI / m_p;
+
+	for (int i = 0; i < n0; ++i) {
+	    double x = ((m_length / 2) - i) * m;
+	    m_window.push_back(sin(x) / x);
+	}
+
+	m_window.push_back(1.0);
+
+	for (int i = 1; i < n1; ++i) {
+	    double x = i * m;
+	    m_window.push_back(sin(x) / x);
+	}
+    }
+}
+