Mask/include/MassLookup.h

/*

MassLookup.h
Generates a map for isotopic masses using AMDC data; subtracts away
electron mass from the atomic mass by default. Creates a static global instance
of this map (MASS) for use throughout code it is included into.

Written by G.W. McCann Aug. 2020

Converted to true singleton to simplify usage -- Aug. 2021 GWM
*/
#ifndef MASS_LOOKUP_H
#define MASS_LOOKUP_H

#include <iostream>
#include <fstream>
#include <string>
#include <unordered_map>
#include <stdexcept>

class MassLookup {

  public:
    ~MassLookup();
    double FindMass(int Z, int A);
    std::string FindSymbol(int Z, int A);
    static MassLookup* GetInstance() {
        if(s_instance == nullptr) {
          s_instance = new MassLookup();
        }
        return s_instance;
    }

  private:
    MassLookup();
    std::unordered_map<std::string, double> massTable;
    std::unordered_map<int, std::string> elementTable;

    static MassLookup* s_instance;

    //constants
    static constexpr double u_to_mev = 931.4940954;
    static constexpr double electron_mass = 0.000548579909;
    
};

#endif