IronOS/source/Core/Inc/history.hpp

/*
 * history.hpp
 *
 *  Created on: 28 Oct, 2018
 *     Authors: Ben V. Brown, David Hilton
 */

#ifndef HISTORY_HPP_
#define HISTORY_HPP_

#include <stdint.h>

// max size = 127
template <class T, uint8_t SIZE> struct history {
  static const uint8_t size = SIZE;
  T                    buf[size];
  uint32_t             sum;
  uint8_t              loc;

  void update(T const val) {
    // step backwards so i+1 is the previous value.

    sum -= buf[loc];
    sum += val;
    buf[loc] = val;
    loc      = (loc + 1) % size;
  }

  T operator[](uint8_t i) const {
    // 0 = newest, size-1 = oldest.
    i = (i + loc) % size;
    return buf[i];
  }

  T average() const { return sum / size; }
};

#endif /* HISTORY_HPP_ */