/* Copyright (c) 1997-2019
   Ewgenij Gawrilow, Michael Joswig, and the polymake team
   Technische Universität Berlin, Germany
   https://polymake.org

   This program 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 2, or (at your option) any
   later version: http://www.gnu.org/licenses/gpl.txt.

   This program 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.
--------------------------------------------------------------------------------
*/


/** @file Map.h
    @brief Implementation of pm::Map class
*/


#ifndef POLYMAKE_MAP_H
#define POLYMAKE_MAP_H

#include "polymake/internal/AVL.h"
#include "polymake/internal/tree_containers.h"
#include "polymake/internal/shared_object.h"
#include "polymake/internal/assoc.h"

namespace pm {

/** @class Map
    @brief Associative array based on AVL::tree.
    
   It differs from the standard @c std::map in the implementation: it uses
   an AVL::tree</a> instead of the red-black tree. The tree is attached via a smart pointer with @ref refcounting "reference counting".

*/


template <typename K, typename D, typename... Params>
class Map
   : public modified_tree< Map<K, D, Params...>,
                           mlist< ContainerTag< AVL::tree< AVL::traits<K, D, Params...> > >,
                                  OperationTag< BuildUnary<AVL::node_accessor> > > > {
protected:
   using tree_type = AVL::tree<AVL::traits<K, D, Params...>>;
   shared_object<tree_type, AliasHandlerTag<shared_alias_handler>> tree;

   friend Map& make_mutable_alias(Map& alias, Map& owner)
   {
      alias.data.make_mutable_alias(owner.data);
      return alias;
   }
public:
   using key_type = K;
   using mapped_type = D;
   using params = typename mlist_wrap<Params...>::type;
   using key_comparator_type = typename mtagged_list_extract<params, ComparatorTag, operations::cmp>::type;
   static constexpr bool is_multimap = tagged_list_extract_integral<params, MultiTag>(false);

   static_assert(!std::is_same<key_comparator_type, operations::cmp_unordered>::value, "comparator must define a total ordering");
   static_assert(!std::is_same<key_comparator_type, operations::cmp>::value || is_ordered<K>::value, "keys must have a total ordering");

   tree_type& get_container() { return *tree; }
   const tree_type& get_container() const { return *tree; }

   /// Create an empty Map. Initialize the element comparator with its default constructor.
   Map() {}

   /// Create an empty Map with non-default comparator.
   explicit Map(const key_comparator_type& cmp_arg)
      : tree(cmp_arg) {}

   /// Construct from an iterator.
   template <typename Iterator>
   Map(Iterator&& src, Iterator&& src_end)
      : tree(make_iterator_range(src, src_end)) {}

   template <typename Iterator>
   explicit Map(Iterator&& src,
                typename std::enable_if<assess_iterator<Iterator, check_iterator_feature, end_sensitive>::value,
                                        void**>::type=nullptr)
      : tree(std::forward<Iterator>(src)) {}

   /// Clear all contents.
   void clear() { tree.apply(shared_clear()); }

   /** @brief Swap content with another Map in an efficient way.
       @param m the other Map
   */
   void swap(Map& m) { tree.swap(m.tree); }

   friend void relocate(Map* from, Map* to)
   {
      relocate(&from->tree, &to->tree);
   }

   bool exists(const key_type& k) const
   {
      return tree->exists(k);
   }

   /** @brief Associative search.
   
       Find the data element associated with the given key. If it doesn't exist so far, it will be created with the default constructor.

       Note that the type of the search key is not necessarily the same as of the map entries.
       It suffices that both are comparable with each other.

       k can also be a container with keys; the result will be a sequence of corresponding values.
   */
   template <typename Keys>
   typename assoc_helper<Map, Keys>::result_type operator[] (const Keys& k)
   {
      return assoc_helper<Map, Keys>()(*this, k);
   }

   /** @brief Associative search (const).
       Find the data element associated with the given key. If it doesn't exist so far, it will raise an exception.

       Note that the type of the search key is not necessarily the same as of the map entries.
       It suffices that both are comparable with each other.

       k can also be a container with keys; the result will be a sequence of corresponding values.
   */
   template <typename Keys>
   typename assoc_helper<const Map, Keys>::result_type operator[] (const Keys& k) const
   {
      return assoc_helper<const Map, Keys>()(*this, k);
   }

   /// synonym for const key lookup
   template <typename Keys>
   typename assoc_helper<const Map, Keys>::result_type map(const Keys& k) const
   {
      return assoc_helper<const Map, Keys>()(*this, k);
   }

   template <typename TKey>
   iterator_range<typename Map::iterator>
   equal_range(const TKey& key)
   {
      auto left=this->find_nearest(keys, polymake::operations::lt());
      auto right=this->find_nearest(keys, polymake::operations::gt());
      if (!left.at_end() || !right.at_end()) ++left;
      return iterator_range<typename Map::iterator>(left, right);
   }

   template <typename TKey>
   iterator_range<typename Map::const_iterator>
   equal_range(const TKey& key) const
   {
      auto left=this->find_nearest(keys, polymake::operations::lt());
      auto right=this->find_nearest(keys, polymake::operations::gt());
      if (!left.at_end() || !right.at_end()) ++left;
      return iterator_range<typename Map::const_iterator>(left, right);
   }

   friend
   bool operator== (const Map& l, const Map& r)
   {
      return l.size()==r.size() && equal_ranges(entire(l), r.begin());
   }

   friend
   bool operator!= (const Map& l, const Map& r)
   {
      return !(l==r);
   }

#if POLYMAKE_DEBUG
   void check(const char* label) const { tree->check(label); }

private:
   void dump(std::false_type) const { cerr << "elements are not printable" << endl; }
   void dump(std::true_type) const { cerr << *this << endl; }
public:
   void dump() const __attribute__((used)) { dump(bool_constant<is_printable<K>::value && is_printable<D>::value>()); }
#endif
};

template <typename K, typename D, typename... Params>
struct spec_object_traits< Map<K, D, Params...> >
   : spec_object_traits<is_container> {
   static const IO_separator_kind IO_separator=IO_sep_inherit;
};

template <typename K, typename D, typename... Params>
struct choose_generic_object_traits< Map<K, D, Params...>, false, false>
   : spec_object_traits< Map<K, D, Params...> > {
   using generic_type = void;
   using generic_tag = is_map;
   using persistent_type = Map<K, D, Params...>;
};

} // end namespace pm

namespace polymake {
   using pm::Map;
}

namespace std {
   template <typename K, typename D, typename... Params>
   void swap(pm::Map<K, D, Params...>& m1, pm::Map<K, D, Params...>& m2) { m1.swap(m2); }
}

#endif // POLYMAKE_MAP_H

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