InstancePool.h

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// Eclipse SUMO, Simulation of Urban MObility; see https://eclipse.org/sumo
// Copyright (C) 2001-2018 German Aerospace Center (DLR) and others.
// This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v2.0
// which accompanies this distribution, and is available at
// http://www.eclipse.org/legal/epl-v20.html
// SPDX-License-Identifier: EPL-2.0
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// A pool of resuable instances
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#ifndef InstancePool_h
#define InstancePool_h


// ===========================================================================
// included modules
// ===========================================================================
#include <config.h>

#include <vector>
#include <algorithm>


// ===========================================================================
// class definitions
// ===========================================================================
template<typename T>
class InstancePool {
public:
    InstancePool(bool deleteOnQuit) : myDeleteOnQuit(deleteOnQuit) { }


    ~InstancePool() {
        typedef typename std::vector<T*>::iterator It;
        if (myDeleteOnQuit) {
            for (It i = myFreeInstances.begin(); i != myFreeInstances.end(); i++) {
                delete *i;
            }
        }
    }


    T* getFreeInstance() {
        if (myFreeInstances.size() == 0) {
            return 0;
        } else {
            T* instance = myFreeInstances.back();
            myFreeInstances.pop_back();
            return instance;
        }
    }


    void addFreeInstance(T* instance) {
        myFreeInstances.push_back(instance);
    }


    void addFreeInstances(const std::vector<T*> instances) {
        std::copy(instances.begin(), instances.end(),
                  std::back_inserter(myFreeInstances));
    }


private:
    std::vector<T*> myFreeInstances;

    bool myDeleteOnQuit;


};


#endif

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