boost/intrusive/splaytree_algorithms.hpp
///////////////////////////////////////////////////////////////////////////// // // (C) Copyright Ion Gaztanaga 2007. // // 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. // ///////////////////////////////////////////////////////////////////////////// // The implementation of splay trees is based on the article and code published // in C++ Users Journal "Implementing Splay Trees in C++" (September 1, 2005). // // The code has been modified and (supposely) improved by Ion Gaztanaga. // Here is the header of the file used as base code: // // splay_tree.h -- implementation of a STL complatible splay tree. // // Copyright (c) 2004 Ralf Mattethat // // Permission to copy, use, modify, sell and distribute this software // is granted provided this copyright notice appears in all copies. // This software is provided "as is" without express or implied // warranty, and with no claim as to its suitability for any purpose. // // Please send questions, comments, complaints, performance data, etc to // ralf.mattethat@teknologisk.dk // // Requirements for element type // * must be copy-constructible // * destructor must not throw exception // // Methods marked with note A only throws an exception if the evaluation of the // predicate throws an exception. If an exception is thrown the call has no // effect on the containers state // // Methods marked with note B only throws an exception if the coppy constructor // or assignment operator of the predicate throws an exception. If an exception // is thrown the call has no effect on the containers state // // iterators are only invalidated, if the element pointed to by the iterator // is deleted. The same goes for element references // #ifndef BOOST_INTRUSIVE_SPLAYTREE_ALGORITHMS_HPP #define BOOST_INTRUSIVE_SPLAYTREE_ALGORITHMS_HPP #include <boost/intrusive/detail/config_begin.hpp> #include <boost/intrusive/detail/assert.hpp> #include <boost/intrusive/intrusive_fwd.hpp> #include <cstddef> #include <boost/intrusive/detail/utilities.hpp> #include <boost/intrusive/detail/tree_algorithms.hpp> namespace boost { namespace intrusive { /// @cond namespace detail { template<class NodeTraits> struct splaydown_rollback { typedef typename NodeTraits::node_ptr node_ptr; splaydown_rollback( const node_ptr *pcur_subtree, node_ptr header , node_ptr leftmost , node_ptr rightmost) : pcur_subtree_(pcur_subtree) , header_(header) , leftmost_(leftmost) , rightmost_(rightmost) {} void release() { pcur_subtree_ = 0; } ~splaydown_rollback() { if(pcur_subtree_){ //Exception can only be thrown by comp, but //tree invariants still hold. *pcur_subtree is the current root //so link it to the header. NodeTraits::set_parent(*pcur_subtree_, header_); NodeTraits::set_parent(header_, *pcur_subtree_); //Recover leftmost/rightmost pointers NodeTraits::set_left (header_, leftmost_); NodeTraits::set_right(header_, rightmost_); } } const node_ptr *pcur_subtree_; node_ptr header_, leftmost_, rightmost_; }; } //namespace detail { /// @endcond //! A splay tree is an implementation of a binary search tree. The tree is //! self balancing using the splay algorithm as described in //! //! "Self-Adjusting Binary Search Trees //! by Daniel Dominic Sleator and Robert Endre Tarjan //! AT&T Bell Laboratories, Murray Hill, NJ //! Journal of the ACM, Vol 32, no 3, July 1985, pp 652-686 //! splaytree_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 circular list //! //! <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 splaytree_algorithms { /// @cond private: typedef detail::tree_algorithms<NodeTraits> tree_algorithms; /// @endcond 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; //! This type is the information that will be //! filled by insert_unique_check typedef typename tree_algorithms::insert_commit_data insert_commit_data; /// @cond private: static node_ptr uncast(const_node_ptr ptr) { return node_ptr(const_cast<node*>(::boost::intrusive::detail::get_pointer(ptr))); } /// @endcond public: static node_ptr begin_node(const_node_ptr header) { return tree_algorithms::begin_node(header); } static node_ptr end_node(const_node_ptr header) { return tree_algorithms::end_node(header); } //! <b>Requires</b>: node is a node of the tree or an node initialized //! by init(...). //! //! <b>Effects</b>: Returns true if the node is initialized by init(). //! //! <b>Complexity</b>: Constant time. //! //! <b>Throws</b>: Nothing. static bool unique(const_node_ptr node) { return tree_algorithms::unique(node); } static void unlink(node_ptr node) { tree_algorithms::unlink(node); } //! <b>Requires</b>: node1 and node2 can't be header nodes //! of two trees. //! //! <b>Effects</b>: Swaps two nodes. After the function node1 will be inserted //! in the position node2 before the function. node2 will be inserted in the //! position node1 had before the function. //! //! <b>Complexity</b>: Logarithmic. //! //! <b>Throws</b>: Nothing. //! //! <b>Note</b>: This function will break container ordering invariants if //! node1 and node2 are not equivalent according to the ordering rules. //! //!Experimental function static void swap_nodes(node_ptr node1, node_ptr node2) { if(node1 == node2) return; node_ptr header1(tree_algorithms::get_header(node1)), header2(tree_algorithms::get_header(node2)); swap_nodes(node1, header1, node2, header2); } //! <b>Requires</b>: node1 and node2 can't be header nodes //! of two trees with header header1 and header2. //! //! <b>Effects</b>: Swaps two nodes. After the function node1 will be inserted //! in the position node2 before the function. node2 will be inserted in the //! position node1 had before the function. //! //! <b>Complexity</b>: Constant. //! //! <b>Throws</b>: Nothing. //! //! <b>Note</b>: This function will break container ordering invariants if //! node1 and node2 are not equivalent according to the ordering rules. //! //!Experimental function static void swap_nodes(node_ptr node1, node_ptr header1, node_ptr node2, node_ptr header2) { tree_algorithms::swap_nodes(node1, header1, node2, header2); } //! <b>Requires</b>: node_to_be_replaced must be inserted in a tree //! and new_node must not be inserted in a tree. //! //! <b>Effects</b>: Replaces node_to_be_replaced in its position in the //! tree with new_node. The tree does not need to be rebalanced //! //! <b>Complexity</b>: Logarithmic. //! //! <b>Throws</b>: Nothing. //! //! <b>Note</b>: This function will break container ordering invariants if //! new_node is not equivalent to node_to_be_replaced according to the //! ordering rules. This function is faster than erasing and inserting //! the node, since no rebalancing and comparison is needed. //! //!Experimental function static void replace_node(node_ptr node_to_be_replaced, node_ptr new_node) { if(node_to_be_replaced == new_node) return; replace_node(node_to_be_replaced, tree_algorithms::get_header(node_to_be_replaced), new_node); } //! <b>Requires</b>: node_to_be_replaced must be inserted in a tree //! with header "header" and new_node must not be inserted in a tree. //! //! <b>Effects</b>: Replaces node_to_be_replaced in its position in the //! tree with new_node. The tree does not need to be rebalanced //! //! <b>Complexity</b>: Constant. //! //! <b>Throws</b>: Nothing. //! //! <b>Note</b>: This function will break container ordering invariants if //! new_node is not equivalent to node_to_be_replaced according to the //! ordering rules. This function is faster than erasing and inserting //! the node, since no rebalancing or comparison is needed. //! //!Experimental function static void replace_node(node_ptr node_to_be_replaced, node_ptr header, node_ptr new_node) { tree_algorithms::replace_node(node_to_be_replaced, header, new_node); } //! <b>Requires</b>: p is a node from the tree except the header. //! //! <b>Effects</b>: Returns the next node of the tree. //! //! <b>Complexity</b>: Average constant time. //! //! <b>Throws</b>: Nothing. static node_ptr next_node(node_ptr p) { return tree_algorithms::next_node(p); } //! <b>Requires</b>: p is a node from the tree except the leftmost node. //! //! <b>Effects</b>: Returns the previous node of the tree. //! //! <b>Complexity</b>: Average constant time. //! //! <b>Throws</b>: Nothing. static node_ptr prev_node(node_ptr p) { return tree_algorithms::prev_node(p); } //! <b>Requires</b>: node must not be part of any tree. //! //! <b>Effects</b>: After the function unique(node) == true. //! //! <b>Complexity</b>: Constant. //! //! <b>Throws</b>: Nothing. //! //! <b>Nodes</b>: If node is inserted in a tree, this function corrupts the tree. static void init(node_ptr node) { tree_algorithms::init(node); } //! <b>Requires</b>: node must not be part of any tree. //! //! <b>Effects</b>: Initializes the header to represent an empty tree. //! unique(header) == true. //! //! <b>Complexity</b>: Constant. //! //! <b>Throws</b>: Nothing. //! //! <b>Nodes</b>: If node is inserted in a tree, this function corrupts the tree. static void init_header(node_ptr header) { tree_algorithms::init_header(header); } //! <b>Requires</b>: "disposer" must be an object function //! taking a node_ptr parameter and shouldn't throw. //! //! <b>Effects</b>: Empties the target tree calling //! <tt>void disposer::operator()(node_ptr)</tt> for every node of the tree //! except the header. //! //! <b>Complexity</b>: Linear to the number of element of the source tree plus the. //! number of elements of tree target tree when calling this function. //! //! <b>Throws</b>: If cloner functor throws. If this happens target nodes are disposed. template<class Disposer> static void clear_and_dispose(node_ptr header, Disposer disposer) { tree_algorithms::clear_and_dispose(header, disposer); } //! <b>Requires</b>: node is a node of the tree but it's not the header. //! //! <b>Effects</b>: Returns the number of nodes of the subtree. //! //! <b>Complexity</b>: Linear time. //! //! <b>Throws</b>: Nothing. static std::size_t count(const_node_ptr node) { return tree_algorithms::count(node); } //! <b>Requires</b>: header is the header node of the tree. //! //! <b>Effects</b>: Returns the number of nodes above the header. //! //! <b>Complexity</b>: Linear time. //! //! <b>Throws</b>: Nothing. static std::size_t size(const_node_ptr header) { return tree_algorithms::size(header); } //! <b>Requires</b>: header1 and header2 must be the header nodes //! of two trees. //! //! <b>Effects</b>: Swaps two trees. After the function header1 will contain //! links to the second tree and header2 will have links to the first tree. //! //! <b>Complexity</b>: Constant. //! //! <b>Throws</b>: Nothing. static void swap_tree(node_ptr header1, node_ptr header2) { return tree_algorithms::swap_tree(header1, header2); } //! <b>Requires</b>: "header" must be the header node of a tree. //! "commit_data" must have been obtained from a previous call to //! "insert_unique_check". No objects should have been inserted or erased //! from the set between the "insert_unique_check" that filled "commit_data" //! and the call to "insert_commit". //! //! //! <b>Effects</b>: Inserts new_node in the set using the information obtained //! from the "commit_data" that a previous "insert_check" filled. //! //! <b>Complexity</b>: Constant time. //! //! <b>Throws</b>: Nothing. //! //! <b>Notes</b>: This function has only sense if a "insert_unique_check" has been //! previously executed to fill "commit_data". No value should be inserted or //! erased between the "insert_check" and "insert_commit" calls. static void insert_unique_commit (node_ptr header, node_ptr new_value, const insert_commit_data &commit_data) { tree_algorithms::insert_unique_commit(header, new_value, commit_data); } //! <b>Requires</b>: "header" must be the header node of a tree. //! KeyNodePtrCompare is a function object that induces a strict weak //! ordering compatible with the strict weak ordering used to create the //! the tree. NodePtrCompare compares KeyType with a node_ptr. //! //! <b>Effects</b>: Checks if there is an equivalent node to "key" in the //! tree according to "comp" and obtains the needed information to realize //! a constant-time node insertion if there is no equivalent node. //! //! <b>Returns</b>: If there is an equivalent value //! returns a pair containing a node_ptr to the already present node //! and false. If there is not equivalent key can be inserted returns true //! in the returned pair's boolean and fills "commit_data" that is meant to //! be used with the "insert_commit" function to achieve a constant-time //! insertion function. //! //! <b>Complexity</b>: Average complexity is at most logarithmic. //! //! <b>Throws</b>: If "comp" throws. //! //! <b>Notes</b>: This function is used to improve performance when constructing //! a node is expensive and the user does not want to have two equivalent nodes //! in the tree: if there is an equivalent value //! the constructed object must be discarded. Many times, the part of the //! node that is used to impose the order is much cheaper to construct //! than the node and this function offers the possibility to use that part //! to check if the insertion will be successful. //! //! If the check is successful, the user can construct the node and use //! "insert_commit" to insert the node in constant-time. This gives a total //! logarithmic complexity to the insertion: check(O(log(N)) + commit(O(1)). //! //! "commit_data" remains valid for a subsequent "insert_unique_commit" only //! if no more objects are inserted or erased from the set. template<class KeyType, class KeyNodePtrCompare> static std::pair<node_ptr, bool> insert_unique_check (node_ptr header, const KeyType &key ,KeyNodePtrCompare comp, insert_commit_data &commit_data) { splay_down(header, key, comp); return tree_algorithms::insert_unique_check(header, key, comp, commit_data); } template<class KeyType, class KeyNodePtrCompare> static std::pair<node_ptr, bool> insert_unique_check (node_ptr header, node_ptr hint, const KeyType &key ,KeyNodePtrCompare comp, insert_commit_data &commit_data) { splay_down(header, key, comp); return tree_algorithms::insert_unique_check(header, hint, key, comp, commit_data); } static bool is_header(const_node_ptr p) { return tree_algorithms::is_header(p); } //! <b>Requires</b>: "header" must be the header node of a tree. //! KeyNodePtrCompare is a function object that induces a strict weak //! ordering compatible with the strict weak ordering used to create the //! the tree. KeyNodePtrCompare can compare KeyType with tree's node_ptrs. //! //! <b>Effects</b>: Returns an node_ptr to the element that is equivalent to //! "key" according to "comp" or "header" if that element does not exist. //! //! <b>Complexity</b>: Logarithmic. //! //! <b>Throws</b>: If "comp" throws. template<class KeyType, class KeyNodePtrCompare> static node_ptr find (const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp, bool splay = true) { if(splay) splay_down(uncast(header), key, comp); node_ptr end = uncast(header); node_ptr y = lower_bound(header, key, comp, false); node_ptr r = (y == end || comp(key, y)) ? end : y; return r; } //! <b>Requires</b>: "header" must be the header node of a tree. //! KeyNodePtrCompare is a function object that induces a strict weak //! ordering compatible with the strict weak ordering used to create the //! the tree. KeyNodePtrCompare can compare KeyType with tree's node_ptrs. //! //! <b>Effects</b>: Returns an a pair of node_ptr delimiting a range containing //! all elements that are equivalent to "key" according to "comp" or an //! empty range that indicates the position where those elements would be //! if they there are no equivalent elements. //! //! <b>Complexity</b>: Logarithmic. //! //! <b>Throws</b>: If "comp" throws. template<class KeyType, class KeyNodePtrCompare> static std::pair<node_ptr, node_ptr> equal_range (const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp, bool splay = true) { //if(splay) //splay_down(uncast(header), key, comp); std::pair<node_ptr, node_ptr> ret = tree_algorithms::equal_range(header, key, comp); if(splay) splay_up(ret.first, uncast(header)); return ret; } //! <b>Requires</b>: "header" must be the header node of a tree. //! KeyNodePtrCompare is a function object that induces a strict weak //! ordering compatible with the strict weak ordering used to create the //! the tree. KeyNodePtrCompare can compare KeyType with tree's node_ptrs. //! //! <b>Effects</b>: Returns an node_ptr to the first element that is //! not less than "key" according to "comp" or "header" if that element does //! not exist. //! //! <b>Complexity</b>: Logarithmic. //! //! <b>Throws</b>: If "comp" throws. template<class KeyType, class KeyNodePtrCompare> static node_ptr lower_bound (const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp, bool splay = true) { //if(splay) //splay_down(uncast(header), key, comp); node_ptr y = tree_algorithms::lower_bound(header, key, comp); if(splay) splay_up(y, uncast(header)); return y; } //! <b>Requires</b>: "header" must be the header node of a tree. //! KeyNodePtrCompare is a function object that induces a strict weak //! ordering compatible with the strict weak ordering used to create the //! the tree. KeyNodePtrCompare can compare KeyType with tree's node_ptrs. //! //! <b>Effects</b>: Returns an node_ptr to the first element that is greater //! than "key" according to "comp" or "header" if that element does not exist. //! //! <b>Complexity</b>: Logarithmic. //! //! <b>Throws</b>: If "comp" throws. template<class KeyType, class KeyNodePtrCompare> static node_ptr upper_bound (const_node_ptr header, const KeyType &key, KeyNodePtrCompare comp, bool splay = true) { //if(splay) //splay_down(uncast(header), key, comp); node_ptr y = tree_algorithms::upper_bound(header, key, comp); if(splay) splay_up(y, uncast(header)); return y; } //! <b>Requires</b>: "header" must be the header node of a tree. //! NodePtrCompare is a function object that induces a strict weak //! ordering compatible with the strict weak ordering used to create the //! the tree. NodePtrCompare compares two node_ptrs. "hint" is node from //! the "header"'s tree. //! //! <b>Effects</b>: Inserts new_node into the tree, using "hint" as a hint to //! where it will be inserted. If "hint" is the upper_bound //! the insertion takes constant time (two comparisons in the worst case). //! //! <b>Complexity</b>: Logarithmic in general, but it is amortized //! constant time if new_node is inserted immediately before "hint". //! //! <b>Throws</b>: If "comp" throws. template<class NodePtrCompare> static node_ptr insert_equal (node_ptr header, node_ptr hint, node_ptr new_node, NodePtrCompare comp) { splay_down(header, new_node, comp); return tree_algorithms::insert_equal(header, hint, new_node, comp); } template<class NodePtrCompare> static node_ptr insert_equal_upper_bound (node_ptr header, node_ptr new_node, NodePtrCompare comp) { splay_down(header, new_node, comp); return tree_algorithms::insert_equal_upper_bound(header, new_node, comp); } template<class NodePtrCompare> static node_ptr insert_equal_lower_bound (node_ptr header, node_ptr new_node, NodePtrCompare comp) { splay_down(header, new_node, comp); return tree_algorithms::insert_equal_lower_bound(header, new_node, comp); } //! <b>Requires</b>: "cloner" must be a function //! object taking a node_ptr and returning a new cloned node of it. "disposer" must //! take a node_ptr and shouldn't throw. //! //! <b>Effects</b>: First empties target tree calling //! <tt>void disposer::operator()(node_ptr)</tt> for every node of the tree //! except the header. //! //! Then, duplicates the entire tree pointed by "source_header" cloning each //! source node with <tt>node_ptr Cloner::operator()(node_ptr)</tt> to obtain //! the nodes of the target tree. If "cloner" throws, the cloned target nodes //! are disposed using <tt>void disposer(node_ptr)</tt>. //! //! <b>Complexity</b>: Linear to the number of element of the source tree plus the. //! number of elements of tree target tree when calling this function. //! //! <b>Throws</b>: If cloner functor throws. If this happens target nodes are disposed. template <class Cloner, class Disposer> static void clone (const_node_ptr source_header, node_ptr target_header, Cloner cloner, Disposer disposer) { tree_algorithms::clone(source_header, target_header, cloner, disposer); } // delete node | complexity : constant | exception : nothrow static void erase(node_ptr header, node_ptr z, bool splay = true) { // node_base* n = t->right; // if( t->left != 0 ){ // node_base* l = t->previous(); // splay_up( l , t ); // n = t->left; // n->right = t->right; // if( n->right != 0 ) // n->right->parent = n; // } // // if( n != 0 ) // n->parent = t->parent; // // if( t->parent->left == t ) // t->parent->left = n; // else // must be ( t->parent->right == t ) // t->parent->right = n; // // if( data_->parent == t ) // data_->parent = find_leftmost(); //posibility 1 if(splay && NodeTraits::get_left(z) != 0 ){ node_ptr l = prev_node(z); splay_up(l, header); } /* //possibility 2 if(splay && NodeTraits::get_left(z) != 0 ){ node_ptr l = NodeTraits::get_left(z); splay_up(l, header); }*//* if(splay && NodeTraits::get_left(z) != 0 ){ node_ptr l = prev_node(z); splay_up_impl(l, z); }*/ /* //possibility 4 if(splay){ splay_up(z, header); }*/ //if(splay) //splay_up(z, header); tree_algorithms::erase(header, z); } // bottom-up splay, use data_ as parent for n | complexity : logarithmic | exception : nothrow static void splay_up(node_ptr n, node_ptr header) { if(n == header){ // do a splay for the right most node instead // this is to boost performance of equal_range/count on equivalent containers in the case // where there are many equal elements at the end n = NodeTraits::get_right(header); } node_ptr t = header; if( n == t ) return; for( ;; ){ node_ptr p = NodeTraits::get_parent(n); node_ptr g = NodeTraits::get_parent(p); if( p == t ) break; if( g == t ){ // zig rotate(n); } else if ((NodeTraits::get_left(p) == n && NodeTraits::get_left(g) == p) || (NodeTraits::get_right(p) == n && NodeTraits::get_right(g) == p) ){ // zig-zig rotate(p); rotate(n); } else{ // zig-zag rotate(n); rotate(n); } } } // top-down splay | complexity : logarithmic | exception : strong, note A template<class KeyType, class KeyNodePtrCompare> static node_ptr splay_down(node_ptr header, const KeyType &key, KeyNodePtrCompare comp) { if(!NodeTraits::get_parent(header)) return header; //Most splay tree implementations use a dummy/null node to implement. //this function. This has some problems for a generic library like Intrusive: // // * The node might not have a default constructor. // * The default constructor could throw. // //We already have a header node. Leftmost and rightmost nodes of the tree //are not changed when splaying (because the invariants of the tree don't //change) We can back up them, use the header as the null node and //reassign old values after the function has been completed. node_ptr t = NodeTraits::get_parent(header); //Check if tree has a single node if(!NodeTraits::get_left(t) && !NodeTraits::get_right(t)) return t; //Backup leftmost/rightmost node_ptr leftmost = NodeTraits::get_left(header); node_ptr rightmost = NodeTraits::get_right(header); { detail::splaydown_rollback<NodeTraits> rollback(&t, header, leftmost, rightmost); node_ptr null = header; node_ptr l = null; node_ptr r = null; for( ;; ){ if(comp(key, t)){ if(NodeTraits::get_left(t) == 0 ) break; if(comp(key, NodeTraits::get_left(t))){ t = tree_algorithms::rotate_right(t); if(NodeTraits::get_left(t) == 0) break; link_right(t, r); } else if(comp(NodeTraits::get_left(t), key)){ link_right(t, r); if(NodeTraits::get_right(t) == 0 ) break; link_left(t, l); } else{ link_right(t, r); } } else if(comp(t, key)){ if(NodeTraits::get_right(t) == 0 ) break; if(comp(NodeTraits::get_right(t), key)){ t = tree_algorithms::rotate_left( t ); if(NodeTraits::get_right(t) == 0 ) break; link_left(t, l); } else if(comp(key, NodeTraits::get_right(t))){ link_left(t, l); if(NodeTraits::get_left(t) == 0) break; link_right(t, r); } else{ link_left(t, l); } } else{ break; } } assemble(t, l, r, null); rollback.release(); } //t is the current root NodeTraits::set_parent(header, t); NodeTraits::set_parent(t, header); //Recover leftmost/rightmost pointers NodeTraits::set_left (header, leftmost); NodeTraits::set_right(header, rightmost); return t; } //! <b>Requires</b>: header must be the header of a tree. //! //! <b>Effects</b>: Rebalances the tree. //! //! <b>Throws</b>: Nothing. //! //! <b>Complexity</b>: Linear. static void rebalance(node_ptr header) { tree_algorithms::rebalance(header); } //! <b>Requires</b>: old_root is a node of a tree. //! //! <b>Effects</b>: Rebalances the subtree rooted at old_root. //! //! <b>Returns</b>: The new root of the subtree. //! //! <b>Throws</b>: Nothing. //! //! <b>Complexity</b>: Linear. static node_ptr rebalance_subtree(node_ptr old_root) { return tree_algorithms::rebalance_subtree(old_root); } //! <b>Requires</b>: "n" must be a node inserted in a tree. //! //! <b>Effects</b>: Returns a pointer to the header node of the tree. //! //! <b>Complexity</b>: Logarithmic. //! //! <b>Throws</b>: Nothing. static node_ptr get_header(node_ptr n) { return tree_algorithms::get_header(n); } private: /// @cond // assemble the three sub-trees into new tree pointed to by t | complexity : constant | exception : nothrow static void assemble( node_ptr t, node_ptr l, node_ptr r, const_node_ptr null_node ) { NodeTraits::set_right(l, NodeTraits::get_left(t)); NodeTraits::set_left(r, NodeTraits::get_right(t)); if(NodeTraits::get_right(l) != 0){ NodeTraits::set_parent(NodeTraits::get_right(l), l); } if(NodeTraits::get_left(r) != 0){ NodeTraits::set_parent(NodeTraits::get_left(r), r); } NodeTraits::set_left (t, NodeTraits::get_right(null_node)); NodeTraits::set_right(t, NodeTraits::get_left(null_node)); if( NodeTraits::get_left(t) != 0 ){ NodeTraits::set_parent(NodeTraits::get_left(t), t); } if( NodeTraits::get_right(t) ){ NodeTraits::set_parent(NodeTraits::get_right(t), t); } } // break link to left child node and attach it to left tree pointed to by l | complexity : constant | exception : nothrow static void link_left(node_ptr& t, node_ptr& l) { NodeTraits::set_right(l, t); NodeTraits::set_parent(t, l); l = t; t = NodeTraits::get_right(t); } // break link to right child node and attach it to right tree pointed to by r | complexity : constant | exception : nothrow static void link_right(node_ptr& t, node_ptr& r) { NodeTraits::set_left(r, t); NodeTraits::set_parent(t, r); r = t; t = NodeTraits::get_left(t); } // rotate n with its parent | complexity : constant | exception : nothrow static void rotate(node_ptr n) { node_ptr p = NodeTraits::get_parent(n); node_ptr g = NodeTraits::get_parent(p); //Test if g is header before breaking tree //invariants that would make is_header invalid bool g_is_header = is_header(g); if(NodeTraits::get_left(p) == n){ NodeTraits::set_left(p, NodeTraits::get_right(n)); if(NodeTraits::get_left(p) != 0) NodeTraits::set_parent(NodeTraits::get_left(p), p); NodeTraits::set_right(n, p); } else{ // must be ( p->right == n ) NodeTraits::set_right(p, NodeTraits::get_left(n)); if(NodeTraits::get_right(p) != 0) NodeTraits::set_parent(NodeTraits::get_right(p), p); NodeTraits::set_left(n, p); } NodeTraits::set_parent(p, n); NodeTraits::set_parent(n, g); if(g_is_header){ if(NodeTraits::get_parent(g) == p) NodeTraits::set_parent(g, n); else{//must be ( g->right == p ) BOOST_INTRUSIVE_INVARIANT_ASSERT(0); NodeTraits::set_right(g, n); } } else{ if(NodeTraits::get_left(g) == p) NodeTraits::set_left(g, n); else //must be ( g->right == p ) NodeTraits::set_right(g, n); } } /// @endcond }; } //namespace intrusive } //namespace boost #include <boost/intrusive/detail/config_end.hpp> #endif //BOOST_INTRUSIVE_SPLAYTREE_ALGORITHMS_HPP