moving_average_impl.h

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#pragma once
 
#include "fl/stl/circular_buffer.h"
#include "fl/stl/type_traits.h"
#include "fl/stl/noexcept.h"
 
namespace fl {
namespace detail {
 
template <typename T, fl::size N = 0>
class MovingAverageImpl {
  public:
    MovingAverageImpl() FL_NOEXCEPT : mSum(T(0)) {}
    explicit MovingAverageImpl(fl::size capacity) : mBuf(capacity), mSum(T(0)) {}
 
    T update(T input) {
        if (mBuf.full()) {
            mSum = mSum - mBuf.front();
        }
        mBuf.push_back(input);
        mSum = mSum + input;
        return value();
    }
 
    T value() const {
        fl::size count = mBuf.size();
        if (count == 0) {
            return T(0);
        }
        return divByCount(mSum, count);
    }
 
    void reset() {
        mBuf.clear();
        mSum = T(0);
    }
 
    bool full() const { return mBuf.full(); }
    fl::size size() const { return mBuf.size(); }
    fl::size capacity() const { return mBuf.capacity(); }
 
    void resize(fl::size new_capacity) {
        mBuf = circular_buffer<T, N>(new_capacity);
        mSum = T(0);
    }
 
  private:
    template <typename U = T>
    static typename fl::enable_if<fl::is_floating_point<U>::value, U>::type
    divByCount(U sum, fl::size count) {
        return sum / static_cast<U>(count);
    }
 
    template <typename U = T>
    static typename fl::enable_if<fl::is_integral<U>::value, U>::type
    divByCount(U sum, fl::size count) {
        return sum / static_cast<U>(count);
    }
 
    template <typename U = T>
    static typename fl::enable_if<!fl::is_floating_point<U>::value &&
                                  !fl::is_integral<U>::value, U>::type
    divByCount(U sum, fl::size count) {
        return sum / U(static_cast<float>(count));
    }
 
    circular_buffer<T, N> mBuf;
    T mSum;
};
 
} // namespace detail
} // namespace fl