position_counter.h

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// Author(s): Wieger Wesselink
// Copyright: see the accompanying file COPYING or copy at
// https://github.com/mCRL2org/mCRL2/blob/master/COPYING
//
// 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 MCRL2_UTILITIES_DETAIL_POSITION_COUNTER_H
#define MCRL2_UTILITIES_DETAIL_POSITION_COUNTER_H
 
#include <cstddef>
#include <vector>
 
namespace mcrl2 {
 
namespace utilities {
 
namespace detail {
 
// Registers the current position (x, y) in a tree, and counts the number of nodes on every depth
struct position_counter
{
  const std::size_t undefined = std::size_t(-1);
  std::size_t x = 0;
  std::size_t y = undefined; // the depth
  std::vector<std::size_t> ycounts;  // counts the number of nodes at a certain depth
 
  void increase()
  {
    if (y == undefined)
    {
      y = 0;
    }
    else
    {
      y++;
    }
    if (y == ycounts.size())
    {
      ycounts.push_back(1);
      x = 0;
    }
    else
    {
      x = ycounts[y]++;
    }
  }
 
  void decrease()
  {
    y--;
  }
 
  bool at(std::size_t x0, std::size_t y0)
  {
    return x == x0 && y == y0;
  }
};
 
} // namespace detail
 
} // namespace utilities
 
} // namespace mcrl2
 
#endif // MCRL2_UTILITIES_DETAIL_POSITION_COUNTER_H