weight_accessor.hpp

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// (C) Copyright Renaud Detry   2007-2011.
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
 
#ifndef TRSL_WEIGHT_ACCESSOR_HPP
#define TRSL_WEIGHT_ACCESSOR_HPP
 
namespace trsl {
  
  template<typename WeightType, typename ElementType>
  struct weight_accessor
  {
    WeightType operator()(ElementType const& e) const
      {
        return 1;
        // You can create your own accessor by copying this class
        // and returning something like
        //   return e.getWeight();
      }
  };
 
  template<typename WeightType, typename ElementType>
  class mp_weight_accessor
  {
  public:
    typedef WeightType (ElementType::*WeightAccessorMethodPointer)() const;
    
    mp_weight_accessor() :
      wptr_(NULL) {}
 
    mp_weight_accessor(WeightAccessorMethodPointer wptr) :
      wptr_(wptr) {}
    
    WeightType operator()(ElementType const& e) const
      {
        if (wptr_ == NULL)
          return 1;
        return (e.*wptr_)();
      }
  private:
    WeightAccessorMethodPointer wptr_;
  };
 
}
 
#endif // include guard