421 lines
18 KiB
C++
421 lines
18 KiB
C++
/////////////////////////////////////////////////////////////////////////////
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//
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// (C) Copyright Ion Gaztanaga 2007-2014
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/intrusive for documentation.
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//
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/////////////////////////////////////////////////////////////////////////////
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//
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// Scapegoat tree algorithms are taken from the paper titled:
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// "Scapegoat Trees" by Igal Galperin Ronald L. Rivest.
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//
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/////////////////////////////////////////////////////////////////////////////
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#ifndef BOOST_INTRUSIVE_SGTREE_ALGORITHMS_HPP
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#define BOOST_INTRUSIVE_SGTREE_ALGORITHMS_HPP
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#include <boost/intrusive/detail/config_begin.hpp>
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#include <boost/intrusive/intrusive_fwd.hpp>
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#include <cstddef>
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#include <boost/intrusive/detail/algo_type.hpp>
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#include <boost/intrusive/bstree_algorithms.hpp>
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#if defined(BOOST_HAS_PRAGMA_ONCE)
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# pragma once
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#endif
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namespace boost {
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namespace intrusive {
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//! sgtree_algorithms is configured with a NodeTraits class, which encapsulates the
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//! information about the node to be manipulated. NodeTraits must support the
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//! following interface:
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//!
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//! <b>Typedefs</b>:
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//!
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//! <tt>node</tt>: The type of the node that forms the binary search tree
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//!
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//! <tt>node_ptr</tt>: A pointer to a node
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//!
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//! <tt>const_node_ptr</tt>: A pointer to a const node
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//!
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//! <b>Static functions</b>:
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//!
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//! <tt>static node_ptr get_parent(const_node_ptr n);</tt>
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//!
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//! <tt>static void set_parent(node_ptr n, node_ptr parent);</tt>
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//!
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//! <tt>static node_ptr get_left(const_node_ptr n);</tt>
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//!
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//! <tt>static void set_left(node_ptr n, node_ptr left);</tt>
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//!
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//! <tt>static node_ptr get_right(const_node_ptr n);</tt>
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//!
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//! <tt>static void set_right(node_ptr n, node_ptr right);</tt>
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template<class NodeTraits>
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class sgtree_algorithms
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#ifndef BOOST_INTRUSIVE_DOXYGEN_INVOKED
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: public bstree_algorithms<NodeTraits>
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#endif
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{
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public:
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typedef typename NodeTraits::node node;
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typedef NodeTraits node_traits;
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typedef typename NodeTraits::node_ptr node_ptr;
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typedef typename NodeTraits::const_node_ptr const_node_ptr;
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/// @cond
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private:
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typedef bstree_algorithms<NodeTraits> bstree_algo;
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/// @endcond
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public:
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//! This type is the information that will be
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//! filled by insert_unique_check
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struct insert_commit_data
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: bstree_algo::insert_commit_data
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{
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std::size_t depth;
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};
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#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
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//! @copydoc ::boost::intrusive::bstree_algorithms::get_header(const const_node_ptr&)
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static node_ptr get_header(const const_node_ptr & n);
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//! @copydoc ::boost::intrusive::bstree_algorithms::begin_node
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static node_ptr begin_node(const const_node_ptr & header);
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//! @copydoc ::boost::intrusive::bstree_algorithms::end_node
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static node_ptr end_node(const const_node_ptr & header);
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//! @copydoc ::boost::intrusive::bstree_algorithms::swap_tree
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static void swap_tree(const node_ptr & header1, const node_ptr & header2);
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//! @copydoc ::boost::intrusive::bstree_algorithms::swap_nodes(const node_ptr&,const node_ptr&)
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static void swap_nodes(const node_ptr & node1, const node_ptr & node2);
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//! @copydoc ::boost::intrusive::bstree_algorithms::swap_nodes(const node_ptr&,const node_ptr&,const node_ptr&,const node_ptr&)
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static void swap_nodes(const node_ptr & node1, const node_ptr & header1, const node_ptr & node2, const node_ptr & header2);
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//! @copydoc ::boost::intrusive::bstree_algorithms::replace_node(const node_ptr&,const node_ptr&)
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static void replace_node(const node_ptr & node_to_be_replaced, const node_ptr & new_node);
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//! @copydoc ::boost::intrusive::bstree_algorithms::replace_node(const node_ptr&,const node_ptr&,const node_ptr&)
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static void replace_node(const node_ptr & node_to_be_replaced, const node_ptr & header, const node_ptr & new_node);
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//Unlink is not possible since tree metadata is needed to update the tree
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//!static void unlink(const node_ptr & node);
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//! @copydoc ::boost::intrusive::bstree_algorithms::unlink_leftmost_without_rebalance
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static node_ptr unlink_leftmost_without_rebalance(const node_ptr & header);
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//! @copydoc ::boost::intrusive::bstree_algorithms::unique(const const_node_ptr&)
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static bool unique(const const_node_ptr & node);
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//! @copydoc ::boost::intrusive::bstree_algorithms::size(const const_node_ptr&)
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static std::size_t size(const const_node_ptr & header);
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//! @copydoc ::boost::intrusive::bstree_algorithms::next_node(const node_ptr&)
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static node_ptr next_node(const node_ptr & node);
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//! @copydoc ::boost::intrusive::bstree_algorithms::prev_node(const node_ptr&)
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static node_ptr prev_node(const node_ptr & node);
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//! @copydoc ::boost::intrusive::bstree_algorithms::init(const node_ptr&)
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static void init(const node_ptr & node);
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//! @copydoc ::boost::intrusive::bstree_algorithms::init_header(const node_ptr&)
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static void init_header(const node_ptr & header);
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#endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
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//! @copydoc ::boost::intrusive::bstree_algorithms::erase(const node_ptr&,const node_ptr&)
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template<class AlphaByMaxSize>
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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)
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{
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bstree_algo::erase(header, z);
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--tree_size;
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if (tree_size > 0 &&
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tree_size < alpha_by_maxsize(max_tree_size)){
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bstree_algo::rebalance(header);
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max_tree_size = tree_size;
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}
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return z;
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}
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#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
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//! @copydoc ::boost::intrusive::bstree_algorithms::clone(const const_node_ptr&,const node_ptr&,Cloner,Disposer)
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template <class Cloner, class Disposer>
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static void clone
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(const const_node_ptr & source_header, const node_ptr & target_header, Cloner cloner, Disposer disposer);
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//! @copydoc ::boost::intrusive::bstree_algorithms::clear_and_dispose(const node_ptr&,Disposer)
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template<class Disposer>
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static void clear_and_dispose(const node_ptr & header, Disposer disposer);
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//! @copydoc ::boost::intrusive::bstree_algorithms::lower_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
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template<class KeyType, class KeyNodePtrCompare>
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static node_ptr lower_bound
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(const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
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//! @copydoc ::boost::intrusive::bstree_algorithms::upper_bound(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
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template<class KeyType, class KeyNodePtrCompare>
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static node_ptr upper_bound
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(const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
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//! @copydoc ::boost::intrusive::bstree_algorithms::find(const const_node_ptr&, const KeyType&,KeyNodePtrCompare)
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template<class KeyType, class KeyNodePtrCompare>
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static node_ptr find
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(const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
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//! @copydoc ::boost::intrusive::bstree_algorithms::equal_range(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
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template<class KeyType, class KeyNodePtrCompare>
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static std::pair<node_ptr, node_ptr> equal_range
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(const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
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//! @copydoc ::boost::intrusive::bstree_algorithms::bounded_range(const const_node_ptr&,const KeyType&,const KeyType&,KeyNodePtrCompare,bool,bool)
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template<class KeyType, class KeyNodePtrCompare>
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static std::pair<node_ptr, node_ptr> bounded_range
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(const const_node_ptr & header, const KeyType &lower_key, const KeyType &upper_key, KeyNodePtrCompare comp
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, bool left_closed, bool right_closed);
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//! @copydoc ::boost::intrusive::bstree_algorithms::count(const const_node_ptr&,const KeyType&,KeyNodePtrCompare)
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template<class KeyType, class KeyNodePtrCompare>
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static std::size_t count(const const_node_ptr & header, const KeyType &key, KeyNodePtrCompare comp);
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#endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
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//! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_upper_bound(const node_ptr&,const node_ptr&,NodePtrCompare)
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template<class NodePtrCompare, class H_Alpha>
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static node_ptr insert_equal_upper_bound
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(const node_ptr & h, const node_ptr & new_node, NodePtrCompare comp
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,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{
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std::size_t depth;
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bstree_algo::insert_equal_upper_bound(h, new_node, comp, &depth);
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rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size);
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return new_node;
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal_lower_bound(const node_ptr&,const node_ptr&,NodePtrCompare)
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template<class NodePtrCompare, class H_Alpha>
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static node_ptr insert_equal_lower_bound
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(const node_ptr & h, const node_ptr & new_node, NodePtrCompare comp
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,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{
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std::size_t depth;
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bstree_algo::insert_equal_lower_bound(h, new_node, comp, &depth);
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rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size);
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return new_node;
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::insert_equal(const node_ptr&,const node_ptr&,const node_ptr&,NodePtrCompare)
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template<class NodePtrCompare, class H_Alpha>
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static node_ptr insert_equal
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(const node_ptr & header, const node_ptr & hint, const node_ptr & new_node, NodePtrCompare comp
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,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{
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std::size_t depth;
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bstree_algo::insert_equal(header, hint, new_node, comp, &depth);
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rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size);
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return new_node;
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::insert_before(const node_ptr&,const node_ptr&,const node_ptr&)
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template<class H_Alpha>
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static node_ptr insert_before
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(const node_ptr & header, const node_ptr & pos, const node_ptr & new_node
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,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{
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std::size_t depth;
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bstree_algo::insert_before(header, pos, new_node, &depth);
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rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size);
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return new_node;
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::push_back(const node_ptr&,const node_ptr&)
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template<class H_Alpha>
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static void push_back(const node_ptr & header, const node_ptr & new_node
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,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{
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std::size_t depth;
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bstree_algo::push_back(header, new_node, &depth);
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rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size);
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::push_front(const node_ptr&,const node_ptr&)
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template<class H_Alpha>
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static void push_front(const node_ptr & header, const node_ptr & new_node
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,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{
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std::size_t depth;
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bstree_algo::push_front(header, new_node, &depth);
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rebalance_after_insertion(new_node, depth, tree_size+1, h_alpha, max_tree_size);
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const const_node_ptr&,const KeyType&,KeyNodePtrCompare,insert_commit_data&)
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template<class KeyType, class KeyNodePtrCompare>
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static std::pair<node_ptr, bool> insert_unique_check
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(const const_node_ptr & header, const KeyType &key
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,KeyNodePtrCompare comp, insert_commit_data &commit_data)
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{
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std::size_t depth;
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std::pair<node_ptr, bool> ret =
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bstree_algo::insert_unique_check(header, key, comp, commit_data, &depth);
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commit_data.depth = depth;
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return ret;
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_check(const const_node_ptr&,const node_ptr&,const KeyType&,KeyNodePtrCompare,insert_commit_data&)
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template<class KeyType, class KeyNodePtrCompare>
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static std::pair<node_ptr, bool> insert_unique_check
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(const const_node_ptr & header, const node_ptr &hint, const KeyType &key
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,KeyNodePtrCompare comp, insert_commit_data &commit_data)
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{
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std::size_t depth;
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std::pair<node_ptr, bool> ret =
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bstree_algo::insert_unique_check
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(header, hint, key, comp, commit_data, &depth);
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commit_data.depth = depth;
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return ret;
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::insert_unique_commit(const node_ptr&,const node_ptr&,const insert_commit_data&)
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template<class H_Alpha>
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BOOST_INTRUSIVE_FORCEINLINE static void insert_unique_commit
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(const node_ptr & header, const node_ptr & new_value, const insert_commit_data &commit_data
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,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{ return insert_commit(header, new_value, commit_data, tree_size, h_alpha, max_tree_size); }
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//! @copydoc ::boost::intrusive::bstree_algorithms::transfer_unique
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template<class NodePtrCompare, class H_Alpha, class AlphaByMaxSize>
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static bool transfer_unique
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( const node_ptr & header1, NodePtrCompare comp, std::size_t tree1_size, std::size_t &max_tree1_size
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, const node_ptr &header2, const node_ptr & z, std::size_t tree2_size, std::size_t &max_tree2_size
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,H_Alpha h_alpha, AlphaByMaxSize alpha_by_maxsize)
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{
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insert_commit_data commit_data;
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bool const transferable = insert_unique_check(header1, z, comp, commit_data).second;
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if(transferable){
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erase(header2, z, tree2_size, max_tree2_size, alpha_by_maxsize);
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insert_commit(header1, z, commit_data, tree1_size, h_alpha, max_tree1_size);
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}
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return transferable;
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}
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//! @copydoc ::boost::intrusive::bstree_algorithms::transfer_equal
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template<class NodePtrCompare, class H_Alpha, class AlphaByMaxSize>
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static void transfer_equal
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( const node_ptr & header1, NodePtrCompare comp, std::size_t tree1_size, std::size_t &max_tree1_size
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, const node_ptr &header2, const node_ptr & z, std::size_t tree2_size, std::size_t &max_tree2_size
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,H_Alpha h_alpha, AlphaByMaxSize alpha_by_maxsize)
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{
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insert_commit_data commit_data;
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insert_equal_upper_bound_check(header1, z, comp, commit_data);
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erase(header2, z, tree2_size, max_tree2_size, alpha_by_maxsize);
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insert_commit(header1, z, commit_data, tree1_size, h_alpha, max_tree1_size);
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}
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#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
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//! @copydoc ::boost::intrusive::bstree_algorithms::is_header
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static bool is_header(const const_node_ptr & p);
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//! @copydoc ::boost::intrusive::bstree_algorithms::is_header
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static void rebalance(const node_ptr & header);
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//! @copydoc ::boost::intrusive::bstree_algorithms::rebalance_subtree
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static node_ptr rebalance_subtree(const node_ptr & old_root)
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#endif //#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
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/// @cond
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private:
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template<class KeyType, class KeyNodePtrCompare>
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static void insert_equal_upper_bound_check
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(const node_ptr & header, const KeyType &key
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,KeyNodePtrCompare comp, insert_commit_data &commit_data)
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{
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std::size_t depth;
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bstree_algo::insert_equal_upper_bound_check(header, key, comp, commit_data, &depth);
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commit_data.depth = depth;
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}
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template<class H_Alpha>
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static void insert_commit
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(const node_ptr & header, const node_ptr & new_value, const insert_commit_data &commit_data
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,std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{
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bstree_algo::insert_unique_commit(header, new_value, commit_data);
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rebalance_after_insertion(new_value, commit_data.depth, tree_size+1, h_alpha, max_tree_size);
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}
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template<class H_Alpha>
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static void rebalance_after_insertion
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(const node_ptr &x, std::size_t depth
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, std::size_t tree_size, H_Alpha h_alpha, std::size_t &max_tree_size)
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{
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if(tree_size > max_tree_size)
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max_tree_size = tree_size;
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if(tree_size > 2 && //Nothing to do with only the root
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//Check if the root node is unbalanced
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//Scapegoat paper depth counts root depth as zero and "depth" counts root as 1,
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//but since "depth" is the depth of the ancestor of x, i == depth
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depth > h_alpha(tree_size)){
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//Find the first non height-balanced node
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//as described in the section 4.2 of the paper.
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//This method is the alternative method described
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//in the paper. Authors claim that this method
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//may tend to yield more balanced trees on the average
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//than the weight balanced method.
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node_ptr s = x;
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std::size_t size = 1;
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for(std::size_t ancestor = 1; ancestor != depth; ++ancestor){
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const node_ptr s_parent = NodeTraits::get_parent(s);
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const node_ptr s_parent_left = NodeTraits::get_left(s_parent);
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//Obtain parent's size (previous size + parent + sibling tree)
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const node_ptr s_sibling = s_parent_left == s ? NodeTraits::get_right(s_parent) : s_parent_left;
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size += 1 + bstree_algo::subtree_size(s_sibling);
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s = s_parent;
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if(ancestor > h_alpha(size)){ //is 's' scapegoat?
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bstree_algo::rebalance_subtree(s);
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return;
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}
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}
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//The whole tree must be rebuilt
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max_tree_size = tree_size;
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bstree_algo::rebalance_subtree(NodeTraits::get_parent(s));
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}
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}
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/// @endcond
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};
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/// @cond
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template<class NodeTraits>
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struct get_algo<SgTreeAlgorithms, NodeTraits>
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{
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typedef sgtree_algorithms<NodeTraits> type;
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};
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template <class ValueTraits, class NodePtrCompare, class ExtraChecker>
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struct get_node_checker<SgTreeAlgorithms, ValueTraits, NodePtrCompare, ExtraChecker>
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{
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typedef detail::bstree_node_checker<ValueTraits, NodePtrCompare, ExtraChecker> type;
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};
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|
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/// @endcond
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|
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} //namespace intrusive
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} //namespace boost
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|
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#include <boost/intrusive/detail/config_end.hpp>
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#endif //BOOST_INTRUSIVE_SGTREE_ALGORITHMS_HPP
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