| ///////////////////////////////////////////////////////////////////////////// |
| // |
| // (C) Copyright Ion Gaztanaga 2007-2014 |
| // |
| // 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) |
| // |
| // See http://www.boost.org/libs/intrusive for documentation. |
| // |
| ///////////////////////////////////////////////////////////////////////////// |
| // |
| // Scapegoat tree algorithms are taken from the paper titled: |
| // "Scapegoat Trees" by Igal Galperin Ronald L. Rivest. |
| // |
| ///////////////////////////////////////////////////////////////////////////// |
| #ifndef BOOST_INTRUSIVE_SGTREE_ALGORITHMS_HPP |
| #define BOOST_INTRUSIVE_SGTREE_ALGORITHMS_HPP |
| |
| #include <boost/intrusive/detail/config_begin.hpp> |
| #include <boost/intrusive/intrusive_fwd.hpp> |
| |
| #include <cstddef> |
| #include <boost/intrusive/detail/algo_type.hpp> |
| #include <boost/intrusive/bstree_algorithms.hpp> |
| |
| #if defined(BOOST_HAS_PRAGMA_ONCE) |
| # pragma once |
| #endif |
| |
| namespace boost { |
| namespace intrusive { |
| |
| //! sgtree_algorithms is configured with a NodeTraits class, which encapsulates the |
| //! information about the node to be manipulated. NodeTraits must support the |
| //! following interface: |
| //! |
| //! <b>Typedefs</b>: |
| //! |
| //! <tt>node</tt>: The type of the node that forms the binary search tree |
| //! |
| //! <tt>node_ptr</tt>: A pointer to a node |
| //! |
| //! <tt>const_node_ptr</tt>: A pointer to a const node |
| //! |
| //! <b>Static functions</b>: |
| //! |
| //! <tt>static node_ptr get_parent(const_node_ptr n);</tt> |
| //! |
| //! <tt>static void set_parent(node_ptr n, node_ptr parent);</tt> |
| //! |
| //! <tt>static node_ptr get_left(const_node_ptr n);</tt> |
| //! |
| //! <tt>static void set_left(node_ptr n, node_ptr left);</tt> |
| //! |
| //! <tt>static node_ptr get_right(const_node_ptr n);</tt> |
| //! |
| //! <tt>static void set_right(node_ptr n, node_ptr right);</tt> |
| template<class NodeTraits> |
| class sgtree_algorithms |
| #ifndef BOOST_INTRUSIVE_DOXYGEN_INVOKED |
| : public bstree_algorithms<NodeTraits> |
| #endif |
| { |
| public: |
| typedef typename NodeTraits::node node; |
| typedef NodeTraits node_traits; |
| typedef typename NodeTraits::node_ptr node_ptr; |
| typedef typename NodeTraits::const_node_ptr const_node_ptr; |
| |
| /// @cond |
| private: |
| |
| typedef bstree_algorithms<NodeTraits> bstree_algo; |
| |
| /// @endcond |
| |
| public: |
| //! This type is the information that will be |
| //! filled by insert_unique_check |
| struct insert_commit_data |
| : bstree_algo::insert_commit_data |
| { |
| std::size_t depth; |
| }; |
| |
| #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED |
| //! @copydoc ::boost::intrusive::bstree_algorithms::get_header(const const_node_ptr&) |
| static node_ptr get_header(const const_node_ptr & n); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::begin_node |
| static node_ptr begin_node(const const_node_ptr & header); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::end_node |
| static node_ptr end_node(const const_node_ptr & header); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::swap_tree |
| static void swap_tree(const node_ptr & header1, const node_ptr & header2); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::swap_nodes(const node_ptr&,const node_ptr&) |
| static void swap_nodes(const node_ptr & node1, const node_ptr & node2); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::swap_nodes(const node_ptr&,const node_ptr&,const node_ptr&,const node_ptr&) |
| static void swap_nodes(const node_ptr & node1, const node_ptr & header1, const node_ptr & node2, const node_ptr & header2); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::replace_node(const node_ptr&,const node_ptr&) |
| static void replace_node(const node_ptr & node_to_be_replaced, const node_ptr & new_node); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::replace_node(const node_ptr&,const node_ptr&,const node_ptr&) |
| static void replace_node(const node_ptr & node_to_be_replaced, const node_ptr & header, const node_ptr & new_node); |
| |
| //Unlink is not possible since tree metadata is needed to update the tree |
| //!static void unlink(const node_ptr & node); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::unlink_leftmost_without_rebalance |
| static node_ptr unlink_leftmost_without_rebalance(const node_ptr & header); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::unique(const const_node_ptr&) |
| static bool unique(const const_node_ptr & node); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::size(const const_node_ptr&) |
| static std::size_t size(const const_node_ptr & header); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::next_node(const node_ptr&) |
| static node_ptr next_node(const node_ptr & node); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::prev_node(const node_ptr&) |
| static node_ptr prev_node(const node_ptr & node); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::init(const node_ptr&) |
| static void init(const node_ptr & node); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::init_header(const node_ptr&) |
| static void init_header(const node_ptr & header); |
| #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::erase(const node_ptr&,const node_ptr&) |
| template<class AlphaByMaxSize> |
| static node_ptr erase(const node_ptr & header, const node_ptr & z, std::size_t tree_size, std::size_t &max_tree_size, AlphaByMaxSize alpha_by_maxsize) |
| { |
| //typename bstree_algo::data_for_rebalance info; |
| bstree_algo::erase(header, z); |
| --tree_size; |
| if (tree_size > 0 && |
| tree_size < alpha_by_maxsize(max_tree_size)){ |
| bstree_algo::rebalance(header); |
| max_tree_size = tree_size; |
| } |
| return z; |
| } |
| |
| #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED |
| //! @copydoc ::boost::intrusive::bstree_algorithms::clone(const const_node_ptr&,const node_ptr&,Cloner,Disposer) |
| template <class Cloner, class Disposer> |
| static void clone |
| (const const_node_ptr & source_header, const node_ptr & target_header, Cloner cloner, Disposer disposer); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::clear_and_dispose(const node_ptr&,Disposer) |
| template<class Disposer> |
| static void clear_and_dispose(const node_ptr & header, Disposer disposer); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::lower_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare) |
| template<class KeyType, class KeyNodePtrCompare> |
| static node_ptr lower_bound |
| (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::upper_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare) |
| template<class KeyType, class KeyNodePtrCompare> |
| static node_ptr upper_bound |
| (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::find(const const_node_ptr&, const KeyType&,KeyNodePtrCompare) |
| template<class KeyType, class KeyNodePtrCompare> |
| static node_ptr find |
| (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::equal_range(const const_node_ptr&,const KeyType&,KeyNodePtrCompare) |
| template<class KeyType, class KeyNodePtrCompare> |
| static std::pair<node_ptr, node_ptr> equal_range |
| (const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::bounded_range(const const_node_ptr&,const KeyType&,const KeyType&,KeyNodePtrCompare,bool,bool) |
| template<class KeyType, class KeyNodePtrCompare> |
| static std::pair<node_ptr, node_ptr> bounded_range |
| (const const_node_ptr & header, const KeyType &lower_key, const KeyType &upper_key, KeyNodePtrCompare comp |
| , bool left_closed, bool right_closed); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::count(const const_node_ptr&,const KeyType&,KeyNodePtrCompare) |
| template<class KeyType, class KeyNodePtrCompare> |
| static std::size_t count(const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp); |
| |
| #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_upper_bound(const node_ptr&,const node_ptr&,NodePtrCompare) |
| template<class NodePtrCompare, class H_Alpha> |
| static node_ptr insert_equal_upper_bound |
| (const node_ptr & h, const node_ptr & new_node, NodePtrCompare comp |
| ,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size) |
| { |
| std::size_t depth; |
| bstree_algo::insert_equal_upper_bound(h, new_node, comp, &depth); |
| rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size); |
| return new_node; |
| } |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_lower_bound(const node_ptr&,const node_ptr&,NodePtrCompare) |
| template<class NodePtrCompare, class H_Alpha> |
| static node_ptr insert_equal_lower_bound |
| (const node_ptr & h, const node_ptr & new_node, NodePtrCompare comp |
| ,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size) |
| { |
| std::size_t depth; |
| bstree_algo::insert_equal_lower_bound(h, new_node, comp, &depth); |
| rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size); |
| return new_node; |
| } |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal(const node_ptr&,const node_ptr&,const node_ptr&,NodePtrCompare) |
| template<class NodePtrCompare, class H_Alpha> |
| static node_ptr insert_equal |
| (const node_ptr & header, const node_ptr & hint, const node_ptr & new_node, NodePtrCompare comp |
| ,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size) |
| { |
| std::size_t depth; |
| bstree_algo::insert_equal(header, hint, new_node, comp, &depth); |
| rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size); |
| return new_node; |
| } |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::insert_before(const node_ptr&,const node_ptr&,const node_ptr&) |
| template<class H_Alpha> |
| static node_ptr insert_before |
| (const node_ptr & header, const node_ptr & pos, const node_ptr & new_node |
| ,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size) |
| { |
| std::size_t depth; |
| bstree_algo::insert_before(header, pos, new_node, &depth); |
| rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size); |
| return new_node; |
| } |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::push_back(const node_ptr&,const node_ptr&) |
| template<class H_Alpha> |
| static void push_back(const node_ptr & header, const node_ptr & new_node |
| ,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size) |
| { |
| std::size_t depth; |
| bstree_algo::push_back(header, new_node, &depth); |
| rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size); |
| } |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::push_front(const node_ptr&,const node_ptr&) |
| template<class H_Alpha> |
| static void push_front(const node_ptr & header, const node_ptr & new_node |
| ,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size) |
| { |
| std::size_t depth; |
| bstree_algo::push_front(header, new_node, &depth); |
| rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size); |
| } |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const const_node_ptr&,const KeyType&,KeyNodePtrCompare,insert_commit_data&) |
| template<class KeyType, class KeyNodePtrCompare> |
| static std::pair<node_ptr, bool> insert_unique_check |
| (const const_node_ptr & header, const KeyType &key |
| ,KeyNodePtrCompare comp, insert_commit_data &commit_data) |
| { |
| std::size_t depth; |
| std::pair<node_ptr, bool> ret = |
| bstree_algo::insert_unique_check(header, key, comp, commit_data, &depth); |
| commit_data.depth = depth; |
| return ret; |
| } |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const const_node_ptr&,const node_ptr&,const KeyType&,KeyNodePtrCompare,insert_commit_data&) |
| template<class KeyType, class KeyNodePtrCompare> |
| static std::pair<node_ptr, bool> insert_unique_check |
| (const const_node_ptr & header, const node_ptr &hint, const KeyType &key |
| ,KeyNodePtrCompare comp, insert_commit_data &commit_data) |
| { |
| std::size_t depth; |
| std::pair<node_ptr, bool> ret = |
| bstree_algo::insert_unique_check |
| (header, hint, key, comp, commit_data, &depth); |
| commit_data.depth = depth; |
| return ret; |
| } |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_commit(const node_ptr&,const node_ptr&,const insert_commit_data&) |
| template<class H_Alpha> |
| static void insert_unique_commit |
| (const node_ptr & header, const node_ptr & new_value, const insert_commit_data &commit_data |
| ,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size) |
| { |
| bstree_algo::insert_unique_commit(header, new_value, commit_data); |
| rebalance_after_insertion(new_value, commit_data.depth, tree_size+1, h_alpha, max_tree_size); |
| } |
| |
| #ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED |
| //! @copydoc ::boost::intrusive::bstree_algorithms::is_header |
| static bool is_header(const const_node_ptr & p); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::is_header |
| static void rebalance(const node_ptr & header); |
| |
| //! @copydoc ::boost::intrusive::bstree_algorithms::rebalance_subtree |
| static node_ptr rebalance_subtree(const node_ptr & old_root) |
| #endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED |
| |
| /// @cond |
| private: |
| |
| template<class H_Alpha> |
| static void rebalance_after_insertion |
| (const node_ptr &x, std::size_t depth |
| , std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size) |
| { |
| if(tree_size > max_tree_size) |
| max_tree_size = tree_size; |
| |
| if(tree_size > 2 && //Nothing to do with only the root |
| //Check if the root node is unbalanced |
| //Scapegoat paper depth counts root depth as zero and "depth" counts root as 1, |
| //but since "depth" is the depth of the ancestor of x, i == depth |
| depth > h_alpha(tree_size)){ |
| |
| //Find the first non height-balanced node |
| //as described in the section 4.2 of the paper. |
| //This method is the alternative method described |
| //in the paper. Authors claim that this method |
| //may tend to yield more balanced trees on the average |
| //than the weight balanced method. |
| node_ptr s = x; |
| std::size_t size = 1; |
| for(std::size_t ancestor = 1; ancestor != depth; ++ancestor){ |
| const node_ptr s_parent = NodeTraits::get_parent(s); |
| const node_ptr s_parent_left = NodeTraits::get_left(s_parent); |
| //Obtain parent's size (previous size + parent + sibling tree) |
| const node_ptr s_sibling = s_parent_left == s ? NodeTraits::get_right(s_parent) : s_parent_left; |
| size += 1 + bstree_algo::subtree_size(s_sibling); |
| s = s_parent; |
| if(ancestor > h_alpha(size)){ //is 's' scapegoat? |
| bstree_algo::rebalance_subtree(s); |
| return; |
| } |
| } |
| //The whole tree must be rebuilt |
| max_tree_size = tree_size; |
| bstree_algo::rebalance_subtree(NodeTraits::get_parent(s)); |
| } |
| } |
| /// @endcond |
| }; |
| |
| /// @cond |
| |
| template<class NodeTraits> |
| struct get_algo<SgTreeAlgorithms, NodeTraits> |
| { |
| typedef sgtree_algorithms<NodeTraits> type; |
| }; |
| |
| template <class ValueTraits, class NodePtrCompare, class ExtraChecker> |
| struct get_node_checker<SgTreeAlgorithms, ValueTraits, NodePtrCompare, ExtraChecker> |
| { |
| typedef detail::bstree_node_checker<ValueTraits, NodePtrCompare, ExtraChecker> type; |
| }; |
| |
| /// @endcond |
| |
| } //namespace intrusive |
| } //namespace boost |
| |
| #include <boost/intrusive/detail/config_end.hpp> |
| |
| #endif //BOOST_INTRUSIVE_SGTREE_ALGORITHMS_HPP |