package org.lsst.ccs.utilities.dsp;
   
   import java.util.Arrays;
   
   /**
    * 
    * @author aubourg
    * 
    */
  public class MedianFilter implements DigitalFilter {
  
  	/**
  	 * 
  	 */
  	private static final long serialVersionUID = 4525960504716400209L;
  
  	public MedianFilter(int sz) {
  		if (sz % 2 == 0) {
  			sz++;
  		}
  		this.sz = sz;
  		history = new double[sz];
  		tmp = new double[sz];
  	}
  
  	public void reset() {
  		Arrays.fill(history, 0);
  		ip = 0;
  	}
  
  	public int getDelay() {
  		return sz / 2;
  	}
  
  	public double flush() {
  		return apply(0);
  	}
  
  	public double apply(double signal) {
  		ip++;
  		if (ip >= sz) {
  			ip = 0;
  		}
  		history[ip] = signal;
  		System.arraycopy(history, 0, tmp, 0, tmp.length);
  		Arrays.sort(tmp);
  		return tmp[sz / 2];
  	}
  
  	public double freqResp(double freq) {
  		return 0;
  	}
  
  	public int getOrder() {
  		return sz;
  	}
  
  	int sz;
  
  	double[] history;
  
  	double[] tmp;
  
  	int ip;
  
  	@Override
  	public Object clone() {
  		try {
  			MedianFilter f = (MedianFilter) super.clone();
  			f.history = new double[sz];
  			f.tmp = new double[sz];
  			return f;
  		} catch (CloneNotSupportedException e) {
  			return null;
  		}
  	}
  
  }