From 575e234b005d45dbcdf2afb274df56aac995ef2a Mon Sep 17 00:00:00 2001
From: Hans-Christoph Steiner <eighthave@users.sourceforge.net>
Date: Thu, 13 Dec 2007 04:10:52 +0000
Subject: imported jsarlo's DSP windowing objects from
 http://crca.ucsd.edu/~jsarlo/pd/windowing.tar.gz which has a date of
 2002-04-06

svn path=/trunk/externals/windowing/; revision=9090
---
 windowFunctions.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 windowFunctions.c

(limited to 'windowFunctions.c')

diff --git a/windowFunctions.c b/windowFunctions.c
new file mode 100644
index 0000000..acb7e9f
--- /dev/null
+++ b/windowFunctions.c
@@ -0,0 +1,136 @@
+/* Copyright (C) 2002 Joseph A. Sarlo
+**
+** 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.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with this program; if not, write to the Free Software
+** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+**
+** jsarlo@mambo.peabody.jhu.edu
+*/
+
+#include <stdlib.h>
+#include <math.h>
+#include <stdio.h>
+#ifdef NT
+#define M_PI 3.14159265358979323846
+#endif
+
+/* modified bessel function of zeroth order */
+double i0(double x);
+
+void fillHanning(float *vec, int n) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = (float)(0.5 * (1 + cos(M_PI * x)));
+  }
+}
+
+void fillHamming(float *vec, int n) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = (float)(0.54 + 0.46 * cos(M_PI * x));
+  }
+}
+
+void fillBlackman(float *vec, int n) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = (float)(0.42 + (0.5 * cos(M_PI * x)) + (0.08 * cos (2 * M_PI * x)));
+  }
+}
+
+void fillConnes(float *vec, int n) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = (float)((1  - (x * x)) * (1 - (x * x)));
+  }
+}
+
+void fillCosine(float *vec, int n) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = (float)cos(M_PI * x / 2);
+  }
+}
+
+void fillWelch(float *vec, int n) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = 1 - (x * x);
+  }
+}
+
+void fillBartlett(float *vec, int n) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = (float)(1 - fabs(x));
+  }
+}
+
+void fillLanczos(float *vec, int n) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    if (x == 0) {
+      vec[i] = 1;
+    }
+    else {
+      vec[i] = (float)(sin(M_PI * x) / (M_PI * x));
+    }
+  }
+}
+
+void fillGaussian(float *vec, int n, float delta) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  if (delta == 0) {
+    delta = 1;
+  }
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = (float)(pow(2, (-1 * (x / delta) * (x / delta))));
+  }
+}
+
+void fillKaiser(float *vec, int n, float alpha) {
+  int i;
+  float xShift = (float)n / 2;
+  float x;
+  for (i = 0; i < n; i++) {
+    x = (i - xShift) / xShift;
+    vec[i] = (float)(i0(alpha * sqrt(1 - (x * x))) / i0(alpha));
+  }
+}
-- 
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