purgeable.h

/*
 *  Copyright (C) 2004-2021 Edward F. Valeev
 *
 *  This file is part of Libint.
 *
 *  Libint is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  Libint is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Libint.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#ifndef _libint2_src_bin_libint_purgeable_h_
#define _libint2_src_bin_libint_purgeable_h_
 
#include <dgvertex.h>
#include <vector>
#include <boost/type_traits.hpp>
 
namespace libint2 {
 
  template <typename T>
  struct DefaultPurgingPolicy {
    static bool purgeable() {
 
      bool result = false;
 
      if (boost::is_base_of<DGVertex,T>::value) { // can only purge DGVertex objects
        result = true;
      }
 
      return result;
    }
 
    static bool purge(const T* ref) {
 
      bool result = false;
 
      try {
        const DGVertex* dgv_ptr = dynamic_cast<const DGVertex*>(ref);
        if (dgv_ptr->dg() == 0)
          result = true;
      }
      catch(...) {
      }
 
      return result;
    }
  };
 
 
  class AbstractPurgeableStack {
    public:
      virtual ~AbstractPurgeableStack() {}
      virtual void purge() =0;
  };
 
  template <typename T, typename Policy = DefaultPurgingPolicy<T> >
    class PurgeableStack : public AbstractPurgeableStack
    {
      protected:
        typedef Policy PurgingPolicy;
 
        virtual ~PurgeableStack() {}
    };
 
  class PurgeableStacks {
    public:
      typedef PurgeableStacks this_type;
      typedef AbstractPurgeableStack stack_type;
 
      static this_type* Instance();
 
      void purge();
      void register_stack(stack_type* stack);
 
    private:
      PurgeableStacks() {}
      static this_type* instance_;
      std::vector<stack_type*> stacks_;
  };
 
};
 
#endif