content: /*
   * Copyright (c) 1997 - 2016
   * Actelion Pharmaceuticals Ltd.
   * Gewerbestrasse 16
   * CH-4123 Allschwil, Switzerland
   *
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice, this
   *    list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright notice,
   *    this list of conditions and the following disclaimer in the documentation
   *    and/or other materials provided with the distribution.
   * 3. Neither the name of the the copyright holder nor the
   *    names of its contributors may be used to endorse or promote products
   *    derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
   * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
   * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * @author Modest v. Korff
   */
  
  package com.actelion.research.calc.filter;
  
  import com.actelion.research.util.ArrayUtils;
  
  /**
   * SlidingWindow
   * Created by korffmo1 on 01.03.16.
   */
  public class SlidingWindow {
  
      private double [] arrFilter;
  
      private int l;
      private int l_half;
  
      public SlidingWindow(double[] arrFilter) {
          this.arrFilter = arrFilter;
          if(arrFilter.length % 2 == 0){
              throw new RuntimeException("Odd number of filter values needed.");
          }
  
          l = arrFilter.length;
          l_half = arrFilter.length/2;
      }
  
      public double [] filter(double [] a) {
  
          double [] aa = new double[a.length+l*2];
          double [] aaa = new double[a.length+l*2];
          System.arraycopy(a, 0, aa, l, a.length);
          int end = aa.length- l_half;
          for (int i = l_half; i < end; i++) {
              double v = 0;
              for (int j = 0; j < arrFilter.length; j++) {
                  int ind = i - l_half + j;
                  v += aa[ind] * arrFilter[j] + 0.5;
              }
              aaa[i] = v;
          }
  
          aa = new double[a.length];
          System.arraycopy(aaa, l, aa, 0, aa.length);
          return aa;
  
      }
  
      public int [] filter(int [] a) {
  
          int [] aa = new int[a.length+l*2];
          int [] aaa = new int[a.length+l*2];
          System.arraycopy(a, 0, aa, l, a.length);
          int end = aa.length- l_half;
          for (int i = l_half; i < end; i++) {
              int v = 0;
              for (int j = 0; j < arrFilter.length; j++) {
                  int ind = i - l_half + j;
                  v += (int)(aa[ind] * arrFilter[j] + 0.5);
              }
              aaa[i] = v;
          }
  
          aa = new int[a.length];
          System.arraycopy(aaa, l, aa, 0, aa.length);
          return aa;
      }
  
      public byte [] filter(byte [] a) {
  
          byte [] aa = new byte[a.length+l*2];
          byte [] aaa = new byte[a.length+l*2];
          System.arraycopy(a, 0, aa, l, a.length);
          int end = aa.length- l_half;
  
          for (int i = l_half; i < end; i++) {
              byte v = 0;
              for (int j = 0; j < arrFilter.length; j++) {
                  int ind = i - l_half + j;
                  v += (byte)(aa[ind] * arrFilter[j] + 0.5);
              }
              aaa[i] = v;
          }
          aa = new byte[a.length];
          System.arraycopy(aaa, l, aa, 0, aa.length);
  
          return aa;
      }
  
      public static void main(String[] args) {
  
          int [] a = {0,0,0,0,100,100,0,0,0,0,0};
  
          double [] f = {0.25,0.5,0.25};
  
          SlidingWindow slidingWindow = new SlidingWindow(f);
  
          int [] aa = slidingWindow.filter(a);
  
          System.out.println(ArrayUtils.toString(aa));
      }
  
  }
  