indirect_cmp.hpp

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//
//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// This file is part of the Generic Graph Component Library
//
// You should have received a copy of the License Agreement for the
// Generic Graph Component Library along with the software;  see the
// file LICENSE.  If not, contact Office of Research, University of Notre
// Dame, Notre Dame, IN  46556.
//
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// granted, provided the text of this NOTICE is retained, a notice that
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// with the COPYRIGHT NOTICE in the LICENSE file, and that the LICENSE
// file is distributed with the modified code.
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// By way of example, but not limitation, Licensor MAKES NO
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// PARTICULAR PURPOSE OR THAT THE USE OF THE LICENSED SOFTWARE COMPONENTS
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//=======================================================================
//

#ifndef BOOST_INDIRECT_CMP_HPP
#define BOOST_INDIRECT_CMP_HPP

#include <functional>
#include <boost/config.hpp>
#include <boost/property_map.hpp>

namespace boost {

  //: indirect_cmp
  //
  // could also do this with compose_f_gx_hx, and the member binder...
  //
  //!category: functors
  //!component: type
  //!tparam: ReadablePropertyMap - a model of ReadablePropertyMap
  //!definition: functor.h
  template <class ReadablePropertyMap, class Compare>
  class indirect_cmp {
  public:
    typedef typename boost::property_traits<ReadablePropertyMap>::value_type T;
    typedef typename boost::property_traits<ReadablePropertyMap>::key_type K;
    typedef K first_argument_type;
    typedef K second_argument_type;
    typedef T result_type;
    inline indirect_cmp(const ReadablePropertyMap& df, const Compare& c = Compare())
      : d(df), cmp(c) { }

    template <class A, class B>
    inline bool 
    operator()(const A& u, const B& v) const {
      T du = get(d, u), dv = get(d, v);
      return cmp(du, dv);
    }
  protected:
    ReadablePropertyMap d;
    Compare cmp;
  };

  template <typename Compare, typename ReadablePropertyMap>
  indirect_cmp<ReadablePropertyMap, Compare>
  make_indirect_cmp(const Compare& cmp, ReadablePropertyMap pmap) {
    indirect_cmp<ReadablePropertyMap, Compare> p(pmap, cmp);
    return p;
  }

  template <class ReadablePropertyMap>
  class indirect_pmap {
  public:
    typedef typename boost::property_traits<ReadablePropertyMap>::value_type T;
    typedef typename boost::property_traits<ReadablePropertyMap>::key_type K;
    typedef K argument_type;
    typedef T result_type;
    inline indirect_pmap(const ReadablePropertyMap& df)
      : d(df) { }

    inline bool operator()(const K& u) const {
      return get(d, u);
    }
  protected:
    ReadablePropertyMap d;
  };

  template <typename ReadablePropertyMap>
  indirect_pmap<ReadablePropertyMap>
  make_indirect_pmap(ReadablePropertyMap pmap) {
    indirect_pmap<ReadablePropertyMap> f(pmap);
    return f;
  }


} // namespace boost


#endif // GGCL_INDIRECT_CMP_HPP