odm/include/basedata.h

#pragma once
#include "traits.h"
#include <vector>

class BaseParameters
{
 public:
 virtual ~BaseParameters();
};

class BaseData
{
 protected:
 static constexpr real fillval = 1.0e10;
 std::vector<real>     data;

 BaseData(size_t n): data(n) {}

 public:
 BaseData() = default;

 const real& V(size_t i) const { return data[i]; }
 real&       V(size_t i) { return data[i]; }

 const real& operator()(size_t i) const { return data[i]; }
 real&       operator()(size_t i) { return data[i]; }

 size_t N() const { return data.size(); }

 bool IsFill(size_t i) const { return V(i) == Fillval(); }

 static real Fillval() { return fillval; }

 explicit operator bool() const { return N() != 0; }
};

class UngriddedData: public BaseData
{
 std::vector<real> lons, lats;

 public:
 template<class Lon, class Lat> UngriddedData(size_t n, Lon genlon, Lat genlat): BaseData(n), lons(n), lats(n)
 {
  for(size_t i = 0; i < n; i++)
  {
   lons[i] = genlon(i);
   lats[i] = genlat(i);
  }
 };

 UngriddedData() = default;

 real Lon(size_t i) const { return lons[i]; }
 real Lat(size_t i) const { return lats[i]; }
};

template<class Data> class DefaultAverager: public Data
{
 static constexpr bool isuv = IsUVData<Data>;
 std::vector<size_t>   count;

 static bool DataOk(const Data* d, size_t i)
 {
  if constexpr(isuv)
   return d->U(i) != Data::Fillval() && d->V(i) != Data::Fillval();
  else
   return d->V(i) != Data::Fillval();
 }

 public:
 void Add(const Data& d)
 {
  if(!d) return;
  if(!*this)
  {
   *static_cast<Data*>(this) = d;
   count.resize(Data::N());
   for(size_t i = 0; i < Data::N(); i++) count[i] = DataOk(this, i) ? 1 : 0;
   return;
  }

  if(Data::N() != d.N()) return;
  for(size_t i = 0; i < Data::N(); i++)
   if(DataOk(&d, i))
   {
    if(DataOk(this, i))
    {
     if constexpr(isuv)
     {
      Data::U(i) += d.U(i);
      Data::U2(i) += d.U2(i);
     }
     Data::V(i) += d.V(i);
     count[i]++;
    }
    else
    {
     if constexpr(isuv)
     {
      Data::U(i)  = d.U(i);
      Data::U2(i) = d.U2(i);
     }
     Data::V(i) = d.V(i);
     count[i]   = 1;
    }
   }
 }

 DefaultAverager& Div()
 {
  if(!*this) return *this;
  for(size_t i = 0; i < Data::N(); i++)
   if(count[i] != 0)
   {
    if constexpr(isuv)
    {
     Data::U(i) /= count[i];
     Data::U2(i) /= count[i];
    }
    Data::V(i) /= count[i];
   }
  return *this;
 }
};

namespace internal
{
template<class Data, class Dummy = void> struct GetAverager_
{
 using type = DefaultAverager<Data>;
};
template<class Data> struct GetAverager_<Data, void_<typename Data::Averager>>
{
 using type = typename Data::Averager;
};
} // namespace internal

template<class Data> using Averager = internal::GetAverager_<Data>::type;