RollingAverage.h

/*
 * RollingAverage.h
 *
  Draws on Arduino Smoothing example,
  Created 22 April 2007
  By David A. Mellis  <dam@mellis.org>
  modified 9 Apr 2012
  by Tom Igoe
  http://www.arduino.cc/en/Tutorial/Smoothing
 
 * This file is part of Mozzi.
 *
 * Copyright 2013-2024 Tim Barrass and the Mozzi Team
 *
 * Mozzi is licensed under the GNU Lesser General Public Licence (LGPL) Version 2.1 or later.
 *
 */
 
#ifndef ROLLINGAVERAGE_H
#define ROLLINGAVERAGE_H
 
#include "mozzi_utils.h" // for trailingZeros()
 
 
template <class T, int WINDOW_LENGTH>
class
    RollingAverage {
 
public:
 
    RollingAverage():index(0),total(0), WINDOW_LENGTH_AS_RSHIFT(trailingZerosConst(WINDOW_LENGTH))
    {
        // initialize all the readings to 0:
        for (int thisReading = 0; thisReading < WINDOW_LENGTH; thisReading++)
            readings[thisReading] = 0;
    }
 
        
    T next(T input)
    {
        return add(input)>>WINDOW_LENGTH_AS_RSHIFT;
    }
 
 
protected:
    
    inline 
    T add(T input){
        // out with the old
        total -= readings[index];
        // in with the new
        total +=  input;
        readings[index] = input;
 
        // advance and wrap index
        ++index &= WINDOW_LENGTH -1;
        return total;
    }
        
    
private:
    T readings[WINDOW_LENGTH];  // the readings from the analog input
    unsigned int index; // the index of the current reading
    long total; // the running total
    const uint8_t WINDOW_LENGTH_AS_RSHIFT;
    
};
 
// no need to show the specialisations
template <int WINDOW_LENGTH>
class RollingAverage <unsigned int, WINDOW_LENGTH>
{
public:
    RollingAverage():index(0),total(0), WINDOW_LENGTH_AS_RSHIFT(trailingZerosConst(WINDOW_LENGTH))
    {
        // initialize all the readings to 0:
        for (int thisReading = 0; thisReading < WINDOW_LENGTH; thisReading++)
            readings[thisReading] = 0;
    }
 
    unsigned int next(unsigned int input)
    {
        // calculate the average:
        // this unsigned cast is the only difference between the int and unsigned int specialisations
        // it tells the shift not to sign extend in from the left
        return (unsigned)add(input)>>WINDOW_LENGTH_AS_RSHIFT;
    }
 
protected:
    
    
    inline 
    unsigned int  add(unsigned int input){
        // out with the old
        total -= readings[index];
        // in with the new
        total +=  input;
        readings[index] = input;
 
        // advance and wrap index
        ++index &= WINDOW_LENGTH -1;
        return total;
    }
    
    
private:
    unsigned int readings[WINDOW_LENGTH];      // the readings from the analog input
    unsigned int index;                  // the index of the current reading
    long total;               // the running total
    const uint8_t WINDOW_LENGTH_AS_RSHIFT;
 
};
 
 
 
template <int WINDOW_LENGTH>
class RollingAverage <float, WINDOW_LENGTH>
{
public:
    RollingAverage():index(0),total(0.0)
    {
        // initialize all the readings to 0:
        for (int thisReading = 0; thisReading < WINDOW_LENGTH; thisReading++)
            readings[thisReading] = 0.0;
    }
 
    float next(float input)
    {
        // out with the old
        total -= readings[index];
        // in with the new
        total +=  input;
        readings[index] = input;
 
        // advance and wrap index
        ++index &= WINDOW_LENGTH -1;
 
        // calculate the average:
        return total/WINDOW_LENGTH;
    }
 
private:
    float readings[WINDOW_LENGTH];      // the readings from the analog input
    unsigned int index;                  // the index of the current reading
    float total;               // the running total
    
};
 
 
// no need to show the specialisations 
#endif        //  #ifndef ROLLINGAVERAGE_H