/*
  This file is part of LilyPond, the GNU music typesetter.

  Copyright (C) 1997--2012 Han-Wen Nienhuys <hanwen@xs4all.nl>

  LilyPond 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.

  LilyPond 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 LilyPond.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef DIRECTION_HH
#define DIRECTION_HH

#include "axis.hh"

enum Direction
{
  UP = 1,
  DOWN = -1,
  LEFT = -1,
  RIGHT = 1,
  MIN = -1,
  MAX = 1,
  CENTER = 0,
  SMALLER = -1,
  BIGGER = 1,
  START = -1,
  STOP = 1,

  /*
    This is necessary to safely write loops,
    since

    dir <= RIGHT

    is otherwise transformed into true unconditionally.
  */
  DIRECTION_LIMIT = 2,
  DIRECTION_NEG_LIMIT = -2,
};

inline Direction
other_dir (Direction const d)
{
  return (Direction) (-d);
}

inline Direction
operator - (Direction const d)
{
  return other_dir (d);
}

// to be deleted soon (after coping with issues 2491 and 2493
inline Direction
flip (Direction *i)
{
  if (*i == (Direction)1)
    *i = (Direction) - 1;
  else if (*i == (Direction) - 1)
    *i = (Direction)1;
  return *i;
}

#define UP_and_DOWN(d) \
  Direction d = UP; d != CENTER; d = (d == UP ? DOWN : CENTER)

#define DOWN_and_UP(d) \
  Direction d = DOWN; d != CENTER; d = (d == DOWN ? UP : CENTER)

#define LEFT_and_RIGHT(d) \
  Direction d = LEFT; d != CENTER; d = (d == LEFT ? RIGHT : CENTER)

/**
   if d > 0: the max operator
   if d < 0: the min operator
*/
template<class T> T minmax (Direction d, T a, T b)
{
  if (d == UP)
    return max (a, b);
  else
    return min (a, b);
}

// String direction_string (Direction, Axis);

#endif // DIRECTION_HH
