label.hh

// Copyright (C) 2007, 2008, 2009 EPITA Research and Development Laboratory (LRDE)
//
// This file is part of Olena.
//
// Olena 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, version 2 of the License.
//
// Olena 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 Olena.  If not, see <http://www.gnu.org/licenses/>.
//
// As a special exception, you may use this file as part of a free
// software project without restriction.  Specifically, if other files
// instantiate templates or use macros or inline functions from this
// file, or you compile this file and link it with other files to produce
// an executable, this file does not by itself cause the resulting
// executable to be covered by the GNU General Public License.  This
// exception does not however invalidate any other reasons why the
// executable file might be covered by the GNU General Public License.

#ifndef MLN_VALUE_LABEL_HH
# define MLN_VALUE_LABEL_HH


# include <mln/debug/format.hh>
# include <mln/metal/math/pow.hh>
# include <mln/trait/value_.hh>
# include <mln/value/concept/symbolic.hh>
# include <mln/value/internal/value_like.hh>
# include <mln/value/internal/convert.hh>
# include <mln/value/internal/encoding.hh>


namespace mln
{

  // Forward declarations.
  namespace value {
    template <unsigned n> struct label;
    template <unsigned n> struct int_u;
  }

  namespace literal {
    struct zero_t;
  }


  namespace trait
  {

    template <unsigned n>
    struct value_< mln::value::label<n> >
    {
    private:
      typedef mln::value::label<n> self_;

    public:

      enum {
        dim = 1,
        nbits = n,
        card  = mln_value_card_from_(n)
      };

      typedef trait::value::nature::symbolic nature;
      typedef trait::value::kind::label      kind;
      typedef mln_value_quant_from_(card)    quant;

      static const self_ min() { return 0; }
      static const self_ max() { return mlc_pow_int(2, n) - 1; }

      static const char* name()
      {
        static std::string s = std::string("label_").append(1, n + '0');
        return s.c_str();
      }

      typedef unsigned comp;
    };

  } // end of namespace trait


  namespace convert
  {

    namespace over_load
    {

      // int_u -> label.
      template <unsigned n>
      void
      from_to_(const value::int_u<n>& from, value::label<n>& to_);

      // int_u -> label.
      template <unsigned n, unsigned m>
      void
      from_to_(const value::int_u<n>& from, value::label<m>& to_);

      // label -> bool.
      template <unsigned n>
      void
      from_to_(const value::label<n>& from, bool& to_);

    } // end of namespace mln::convert::over_load

  } // end of namespace mln::convert

  namespace value
  {


    template <unsigned n>
    struct label
      : public Symbolic< label<n> >,
        public internal::value_like_< unsigned,    // Equivalent.
                                      typename internal::encoding_unsigned_<n>::ret, // Enc.
                                      int,    // Interoperation.
                                      label<n> >   // Exact.

    {
    public:
      typedef typename internal::encoding_unsigned_<n>::ret enc;

      label();

      label(unsigned i);

      label(const literal::zero_t& v);

      operator unsigned() const;

      label<n>& operator=(unsigned i);

      label<n>& operator=(const literal::zero_t& v);

      label<n>& operator++();

      label<n>& operator--();

      label<n> next() const;

      label<n> prev() const;

    };


    // Safety.
    template <> struct label<0>;
    template <> struct label<1>;

    template <unsigned n>
    std::ostream& operator<<(std::ostream& ostr, const label<n>& l);


  } // end of namespace mln::value


# ifndef MLN_INCLUDE_ONLY


  namespace convert
  {

    namespace over_load
    {

      // int_u -> label.
      template <unsigned n>
      inline
      void
      from_to_(const value::int_u<n>& from, value::label<n>& to_)
      {
        to_ = from;
      }

      // int_u<n> -> label<m> with n < m.
      template <unsigned n, unsigned m>
      inline
      void
      from_to_(const value::int_u<n>& from, value::label<m>& to_)
      {
        enum { valid = n < m };
        metal::bool_<valid>::check();
        to_ = from;
      }

      template <unsigned n>
      inline
      void
      from_to_(const value::label<n>& from, bool& to_)
      {
        to_ = (from != 0u);
      }

    } // end of namespace mln::convert::over_load

  } // end of namespace mln::convert



  namespace value
  {

    template <unsigned n>
    inline
    label<n>::label()
    {
    }

    template <unsigned n>
    inline
    label<n>::label(unsigned i)
    {
      this->v_ = enc(i);
    }

    template <unsigned n>
    inline
    label<n>::label(const literal::zero_t&)
    {
      this->v_ = 0;
    }

    template <unsigned n>
    inline
    label<n>::operator unsigned() const
    {
      return this->to_enc();
    }

    template <unsigned n>
    inline
    label<n>&
    label<n>::operator=(unsigned i)
    {
      mln_precondition(i <= mln_max(enc));
      this->v_ = enc(i);
      return *this;
    }

    template <unsigned n>
    inline
    label<n>&
    label<n>::operator=(const literal::zero_t&)
    {
      this->v_ = 0;
      return *this;
    }

    template <unsigned n>
    inline
    label<n>&
    label<n>::operator++()
    {
      mln_precondition(this->v_ < mln_max(enc));
      ++this->v_;
      return *this;
    }

    template <unsigned n>
    inline
    label<n>&
    label<n>::operator--()
    {
      mln_precondition(this->v_ != 0);
      --this->v_;
      return *this;
    }

    template <unsigned n>
    inline
    label<n>
    label<n>::next() const
    {
      return label<n>(this->v_ + 1);
    }

    template <unsigned n>
    inline
    label<n>
    label<n>::prev() const
    {
      return label<n>(this->v_ - 1);
    }

    template <unsigned n>
    inline
    std::ostream& operator<<(std::ostream& ostr, const label<n>& i)
    {
      return ostr << debug::format(i.to_equiv());
    }

  } // end of namespace mln::value


# endif // ! MLN_INCLUDE_ONLY

} // end of namespace mln


#endif // ! MLN_VALUE_LABEL_HH

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