IDNumberGen.cxx

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//  IDNumberGen.cxx
//  garsoft-mrb
//
//  Created by Leo Bellantoni on 2 Aug, 2019
//  With lots of help from Paul Russo :)



#include "ReconstructionDataProducts/IDNumberGen.h"



namespace gar {
    namespace rec {



        IDNumberGen* IDNumberGen::create(IDNumber iniValue) { 

            // Repeated calls to new here do not create a memory leak.
            // Some kind of wierd C++11 magic.
            static IDNumberGen* tmp = new IDNumberGen();
            // If creating an instance with an initial value
            if (iniValue != std::numeric_limits<IDNumber>::max()) {
                // and if the iniValue isn't one of the previously used ones
                std::set<IDNumber>::iterator itr = previousInitializers.find(iniValue);
                if (itr==previousInitializers.end()) {
                    previousInitializers.insert(iniValue);
                    nextOneToMake.store(iniValue);
                }
            }
            // Even if nextOneToMake.store() not called, still fine that tmp is
            // uninitialized as getNewOne() only pulls info from a static field.
            return tmp;
        }



        gar::rec::IDNumber IDNumberGen::getNewOne() {
            gar::rec::IDNumber retval = nextOneToMake;
            nextOneToMake.store(nextOneToMake+1);
            return retval;
        }



        void IDNumberGen::newEventReset() {
            previousInitializers.clear();
            nextOneToMake.store(std::numeric_limits<IDNumber>::max());
            return;
        }



        std::atomic<gar::rec::IDNumber> IDNumberGen::nextOneToMake = std::numeric_limits<IDNumber>::max();
        std::set<gar::rec::IDNumber>    IDNumberGen::previousInitializers = {};

        IDNumberGen::IDNumberGen() {}

    } // rec
} // gar