height.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_MORPHO_ATTRIBUTE_HEIGHT_HH
# define MLN_MORPHO_ATTRIBUTE_HEIGHT_HH


# include <mln/accu/internal/base.hh>

# include <mln/util/pix.hh>
# include <mln/math/diff_abs.hh>
# include <mln/math/min.hh>
# include <mln/math/max.hh>


namespace mln
{

  // Forward declaration.
  namespace morpho {
    namespace attribute {
      template <typename I> class height;
    }
  }


  // Traits.

  namespace trait
  {

    template <typename I>
    struct accumulator_< morpho::attribute::height<I> >
    {
      typedef accumulator::has_untake::no    has_untake;
      typedef accumulator::has_set_value::no has_set_value;
      typedef accumulator::has_stop::no      has_stop;
      typedef accumulator::when_pix::use_v   when_pix;
    };

  } // end of namespace mln::trait


  namespace morpho
  {

    namespace attribute
    {

      template <typename I>
      struct height
        : public mln::accu::internal::base< unsigned , height<I> >
      {
        typedef mln_value(I) argument;

        height();

        void init();
        void take(const mln_value(I)& v);
        void take(const util::pix<I>& v);
        void take(const height<I>& other);
        void take_as_init_(const mln_value(I)& v);
        void take_as_init_(const util::pix<I>& px);

        bool is_valid() const;

        unsigned to_result() const;

        unsigned base_level() const;
        unsigned current_level() const;


      protected:
        unsigned ref_;
        unsigned cur_;
        bool initialized_;
      };


# ifndef MLN_INCLUDE_ONLY

      template <typename I>
      inline
      height<I>::height()
        : initialized_ (false)
      {
      }

      template <typename I>
      inline
      void
      height<I>::init()
      {
        mln_invariant(0);
      }

      template <typename I>
      inline
      void
      height<I>::take(const mln_value(I)& v)
      {
        if (!is_valid ())
          {
            take_as_init_(v);
          }
        cur_ = v;
      }

      template <typename I>
      inline
      void
      height<I>::take(const util::pix<I>& px)
      {
        take(px.v());
      }

      template <typename I>
      inline
      void
      height<I>::take(const height<I>& other)
      {
        mln_invariant(((ref_ <= cur_) && (other.ref_ <= other.cur_))
                      || ((ref_ >= cur_) && (other.ref_ >= other.cur_)));

        if (!is_valid())
          {
            ref_ = other.ref_;
            cur_ = other.cur_;
          }
        else if (ref_ < cur_)
          {
            // Values are increasing.
            ref_ = math::min(ref_, other.ref_);
            cur_ = math::max(cur_, other.cur_);
          }
        else
          {
            // Values are decreasing.
            ref_ = math::max(ref_, other.ref_);
            cur_ = math::min(cur_, other.cur_);
          }
      }

      template <typename I>
      inline
      void
      height<I>::take_as_init_(const mln_value(I)& v)
      {
        cur_ = ref_ = v;
        initialized_ = true;
      }

      template <typename I>
      inline
      void
      height<I>::take_as_init_(const util::pix<I>& px)
      {
        take_as_init_(px.v());
      }


      template <typename I>
      inline
      unsigned
      height<I>::to_result() const
      {
        mln_invariant(is_valid());

        return math::diff_abs(ref_, cur_);
      }

      template <typename I>
      inline
      unsigned
      height<I>::base_level() const
      {
        return ref_;
      }

      template <typename I>
      inline
      unsigned
      height<I>::current_level() const
      {
        return cur_;
      }


      template <typename I>
      inline
      bool
      height<I>::is_valid() const
      {
        return initialized_;
      }

# endif // ! MLN_INCLUDE_ONLY

    } // end of namespace mln::morpho::attribute

  } // end of namespace mln::morpho

} // end of namespace mln


#endif // ! MLN_MORPHO_ATTRIBUTE_HEIGHT_HH