//
//=======================================================================
// Copyright 1997, 1998, 1999, 2000 University of Notre Dame.
// Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// https://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
//
// $URL: https://github.com/CGAL/cgal/blob/releases/CGAL-4.14.3/STL_Extension/include/CGAL/internal/boost/array_binary_tree.hpp $
// $Id: array_binary_tree.hpp a472c24 2019-03-20T08:59:22+01:00 Andreas Fabri
// SPDX-License-Identifier: BSL-1.0
//
// NOTE: this file have been taken from boost 1.46.1 for using
//       with Modificable_priority_queue (to enhance the 
//       non-documented mutable_queue).
//       original file is <boost/graph/detail/array_binary_tree.hpp>
//
#ifndef CGAL_INTERNAL_ARRAY_BINARY_TREE_HPP
#define CGAL_INTERNAL_ARRAY_BINARY_TREE_HPP

#include <CGAL/iterator.h>

#include <boost/config.hpp>

#include <functional>

namespace CGAL { namespace internal {
namespace boost_ {

/*
 * Note: array_binary_tree is a completey balanced binary tree.
 */
#if !defined BOOST_NO_STD_ITERATOR_TRAITS
  template <class RandomAccessIterator, class ID>
#else
  template <class RandomAccessIterator, class ValueType, class ID>
#endif
class array_binary_tree_node {
public:
  typedef array_binary_tree_node ArrayBinaryTreeNode;
  typedef RandomAccessIterator rep_iterator;
#if !defined BOOST_NO_STD_ITERATOR_TRAITS
  typedef typename std::iterator_traits<RandomAccessIterator>::difference_type
          difference_type;
  typedef typename std::iterator_traits<RandomAccessIterator>::value_type
          value_type;
#else
  typedef int difference_type;
  typedef ValueType value_type;
#endif
  typedef difference_type size_type;

  struct children_type {
    struct iterator
      : public CGAL::cpp98::iterator<std::forward_iterator_tag,
                                     ArrayBinaryTreeNode,
                                     difference_type>
    { // replace with iterator_adaptor implementation -JGS
      inline iterator() : i(0), n(0) { }
      inline iterator(const iterator& x) : r(x.r), i(x.i), n(x.n), id(x.id) { }
      inline iterator& operator=(const iterator& x) {
        r = x.r; i = x.i; n = x.n;
        /*egcs generate a warning*/
        id = x.id;
        return *this;
      }
      inline iterator(rep_iterator rr,
                      size_type ii,
                      size_type nn,
                      const ID& _id) : r(rr), i(ii), n(nn), id(_id) { }
      inline array_binary_tree_node operator*() {
        return ArrayBinaryTreeNode(r, i, n, id); }
      inline iterator& operator++() { ++i; return *this; }
      inline iterator operator++(int)
        { iterator t = *this; ++(*this); return t; }
      inline bool operator==(const iterator& x) const { return i == x.i; }
      inline bool operator!=(const iterator& x) const
        { return !(*this == x); }
      rep_iterator r;
      size_type i;
      size_type n;
      ID id;
    };
    inline children_type() : i(0), n(0) { }
    inline children_type(const children_type& x)
      : r(x.r), i(x.i), n(x.n), id(x.id) { }
    inline children_type& operator=(const children_type& x) {
      r = x.r; i = x.i; n = x.n;
      /*egcs generate a warning*/
      id = x.id;
      return *this;
    }
    inline children_type(rep_iterator rr,
                         size_type ii,
                         size_type nn,
                         const ID& _id) : r(rr), i(ii), n(nn), id(_id) { }
    inline iterator begin() { return iterator(r, 2 * i + 1, n, id); }
    inline iterator end() { return iterator(r, 2 * i + 1 + size(), n, id); }
    inline size_type size() const {
      size_type c = 2 * i + 1;
      size_type s;
      if      (c + 1 < n) s = 2;
      else if (c < n)     s = 1;
      else                s = 0;
      return s;
    }
    rep_iterator r;
    size_type i;
    size_type n;
    ID id;
  };
  inline array_binary_tree_node() : i(0), n(0) { }
  inline array_binary_tree_node(const array_binary_tree_node& x)
    : r(x.r), i(x.i), n(x.n), id(x.id) { }
  inline ArrayBinaryTreeNode& operator=(const ArrayBinaryTreeNode& x) {
    r = x.r;
    i = x.i;
    n = x.n;
    /*egcs generate a warning*/
    id = x.id;
    return *this;
  }
  inline array_binary_tree_node(rep_iterator start,
                                rep_iterator end,
                                rep_iterator pos, const ID& _id)
    : r(start), i(pos - start), n(end - start), id(_id) { }
  inline array_binary_tree_node(rep_iterator rr,
                                size_type ii,
                                size_type nn, const ID& _id)
    : r(rr), i(ii), n(nn), id(_id) { }
  inline value_type& value() { return *(r + i); }
  inline const value_type& value() const { return *(r + i); }
  inline ArrayBinaryTreeNode parent() const {
    return ArrayBinaryTreeNode(r, (i - 1) / 2, n, id);
  }
  inline bool has_parent() const { return i != 0; }
  inline children_type children() { return children_type(r, i, n, id); }
  /*
  inline void swap(array_binary_tree_node x) {
    value_type tmp = x.value();
    x.value() = value();
    value() = tmp;
    i = x.i;
  }
  */
  template <class ExternalData>
  inline void swap(ArrayBinaryTreeNode x, ExternalData& edata ) {
    using ::boost::get;

    value_type tmp = x.value();

    /*swap external data*/
    edata[ get(id, tmp) ]     = i;
    edata[ get(id, value()) ] = x.i;

    x.value() = value();
    value() = tmp;
    i = x.i;
  }
   inline const children_type children() const {
    return children_type(r, i, n);
  }
  inline size_type index() const { return i; }
  rep_iterator r;
  size_type i;
  size_type n;
  ID id;
};

template <class RandomAccessContainer,
       class Compare = std::less<typename RandomAccessContainer::value_type> >
struct compare_array_node {
  typedef typename RandomAccessContainer::value_type value_type;
  compare_array_node(const Compare& x) : comp(x) {}
  compare_array_node(const compare_array_node& x) : comp(x.comp) {}

  template< class node_type >
  inline bool operator()(const node_type& x, const node_type& y) {
    return comp(x.value(), y.value());
  }

  template< class node_type >
  inline bool operator()(const node_type& x, const node_type& y) const {
    return comp(x.value(), y.value());
  }
  Compare comp;
};

} } } //namespace CGAL::internal::boost_

#endif /* CGAL_INTERNAL_ARRAY_BINARY_TREE_HPP */
