boost/intrusive/avltree_algorithms.hpp
///////////////////////////////////////////////////////////////////////////// // // (C) Copyright Daniel K. O. 2005. // (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. // ///////////////////////////////////////////////////////////////////////////// #ifndef BOOST_INTRUSIVE_AVLTREE_ALGORITHMS_HPP #define BOOST_INTRUSIVE_AVLTREE_ALGORITHMS_HPP #include <boost/intrusive/detail/config_begin.hpp> #include <cstddef> #include <boost/intrusive/intrusive_fwd.hpp> #include <boost/intrusive/detail/assert.hpp> #include <boost/intrusive/detail/utilities.hpp> #include <boost/intrusive/detail/tree_algorithms.hpp> namespace boost { namespace intrusive { //! avltree_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 //! //! <tt>balance</tt>: The type of the balance factor //! //! <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> //! //! <tt>static balance get_balance(const_node_ptr n);</tt> //! //! <tt>static void set_balance(node_ptr n, balance b);</tt> //! //! <tt>static balance negative();</tt> //! //! <tt>static balance zero();</tt> //! //! <tt>static balance positive();</tt> template<class NodeTraits> class avltree_algorithms { 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; typedef typename NodeTraits::balance balance; /// @cond private: typedef detail::tree_algorithms<NodeTraits> tree_algorithms; template<class F> struct avltree_node_cloner : private detail::ebo_functor_holder<F> { typedef detail::ebo_functor_holder<F> base_t; avltree_node_cloner(F f) : base_t(f) {} node_ptr operator()(node_ptr p) { node_ptr n = base_t::get()(p); NodeTraits::set_balance(n, NodeTraits::get_balance(p)); return n; } }; struct avltree_erase_fixup { void operator()(node_ptr to_erase, node_ptr successor) { NodeTraits::set_balance(successor, NodeTraits::get_balance(to_erase)); } }; static node_ptr uncast(const_node_ptr ptr) { return node_ptr(const_cast<node*>(::boost::intrusive::detail::boost_intrusive_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); } //! This type is the information that will be //! filled by insert_unique_check typedef typename tree_algorithms::insert_commit_data insert_commit_data; //! <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>: 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) { if(node1 == node2) return; tree_algorithms::swap_nodes(node1, header1, node2, header2); //Swap balance balance c = NodeTraits::get_balance(node1); NodeTraits::set_balance(node1, NodeTraits::get_balance(node2)); NodeTraits::set_balance(node2, c); } //! <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); NodeTraits::set_balance(new_node, NodeTraits::get_balance(node_to_be_replaced)); } //! <b>Requires</b>: node is a tree node but not the header. //! //! <b>Effects</b>: Unlinks the node and rebalances the tree. //! //! <b>Complexity</b>: Average complexity is constant time. //! //! <b>Throws</b>: Nothing. static void unlink(node_ptr node) { node_ptr x = NodeTraits::get_parent(node); if(x){ while(!is_header(x)) x = NodeTraits::get_parent(x); erase(x, node); } } //! <b>Requires</b>: header is the header of a tree. //! //! <b>Effects</b>: Unlinks the leftmost node from the tree, and //! updates the header link to the new leftmost node. //! //! <b>Complexity</b>: Average complexity is constant time. //! //! <b>Throws</b>: Nothing. //! //! <b>Notes</b>: This function breaks the tree and the tree can //! only be used for more unlink_leftmost_without_rebalance calls. //! This function is normally used to achieve a step by step //! controlled destruction of the tree. static node_ptr unlink_leftmost_without_rebalance(node_ptr header) { return tree_algorithms::unlink_leftmost_without_rebalance(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); } //! <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>: 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); NodeTraits::set_balance(header, NodeTraits::zero()); } //! <b>Requires</b>: header must be the header of a tree, z a node //! of that tree and z != header. //! //! <b>Effects</b>: Erases node "z" from the tree with header "header". //! //! <b>Complexity</b>: Amortized constant time. //! //! <b>Throws</b>: Nothing. static node_ptr erase(node_ptr header, node_ptr z) { typename tree_algorithms::data_for_rebalance info; tree_algorithms::erase(header, z, avltree_erase_fixup(), info); node_ptr x = info.x; node_ptr x_parent = info.x_parent; //Rebalance avltree rebalance_after_erasure(header, x, x_parent); return z; } //! <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) { avltree_node_cloner<Cloner> new_cloner(cloner); tree_algorithms::clone(source_header, target_header, new_cloner, disposer); } //! <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>: "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) { return tree_algorithms::lower_bound(header, key, comp); } //! <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) { return tree_algorithms::upper_bound(header, key, comp); } //! <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) { return tree_algorithms::find(header, key, comp); } //! <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) { return tree_algorithms::equal_range(header, key, comp); } //! <b>Requires</b>: "h" 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. //! //! <b>Effects</b>: Inserts new_node into the tree before the upper bound //! according to "comp". //! //! <b>Complexity</b>: Average complexity for insert element is at //! most logarithmic. //! //! <b>Throws</b>: If "comp" throws. template<class NodePtrCompare> static node_ptr insert_equal_upper_bound (node_ptr h, node_ptr new_node, NodePtrCompare comp) { tree_algorithms::insert_equal_upper_bound(h, new_node, comp); rebalance_after_insertion(h, new_node); return new_node; } //! <b>Requires</b>: "h" 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. //! //! <b>Effects</b>: Inserts new_node into the tree before the lower bound //! according to "comp". //! //! <b>Complexity</b>: Average complexity for insert element is at //! most logarithmic. //! //! <b>Throws</b>: If "comp" throws. template<class NodePtrCompare> static node_ptr insert_equal_lower_bound (node_ptr h, node_ptr new_node, NodePtrCompare comp) { tree_algorithms::insert_equal_lower_bound(h, new_node, comp); rebalance_after_insertion(h, new_node); return new_node; } //! <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) { tree_algorithms::insert_equal(header, hint, new_node, comp); rebalance_after_insertion(header, new_node); return new_node; } //! <b>Requires</b>: "header" must be the header node of a tree. //! "pos" must be a valid iterator or header (end) node. //! "pos" must be an iterator pointing to the successor to "new_node" //! once inserted according to the order of already inserted nodes. This function does not //! check "pos" and this precondition must be guaranteed by the caller. //! //! <b>Effects</b>: Inserts new_node into the tree before "pos". //! //! <b>Complexity</b>: Constant-time. //! //! <b>Throws</b>: Nothing. //! //! <b>Note</b>: If "pos" is not the successor of the newly inserted "new_node" //! tree invariants might be broken. static node_ptr insert_before (node_ptr header, node_ptr pos, node_ptr new_node) { tree_algorithms::insert_before(header, pos, new_node); rebalance_after_insertion(header, new_node); return new_node; } //! <b>Requires</b>: "header" must be the header node of a tree. //! "new_node" must be, according to the used ordering no less than the //! greatest inserted key. //! //! <b>Effects</b>: Inserts new_node into the tree before "pos". //! //! <b>Complexity</b>: Constant-time. //! //! <b>Throws</b>: Nothing. //! //! <b>Note</b>: If "new_node" is less than the greatest inserted key //! tree invariants are broken. This function is slightly faster than //! using "insert_before". static void push_back(node_ptr header, node_ptr new_node) { tree_algorithms::push_back(header, new_node); rebalance_after_insertion(header, new_node); } //! <b>Requires</b>: "header" must be the header node of a tree. //! "new_node" must be, according to the used ordering, no greater than the //! lowest inserted key. //! //! <b>Effects</b>: Inserts new_node into the tree before "pos". //! //! <b>Complexity</b>: Constant-time. //! //! <b>Throws</b>: Nothing. //! //! <b>Note</b>: If "new_node" is greater than the lowest inserted key //! tree invariants are broken. This function is slightly faster than //! using "insert_before". static void push_front(node_ptr header, node_ptr new_node) { tree_algorithms::push_front(header, new_node); rebalance_after_insertion(header, new_node); } //! <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 (const_node_ptr header, const KeyType &key ,KeyNodePtrCompare comp, insert_commit_data &commit_data) { return tree_algorithms::insert_unique_check(header, key, comp, 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. //! "hint" is node from the "header"'s tree. //! //! <b>Effects</b>: Checks if there is an equivalent node to "key" in the //! tree according to "comp" using "hint" as a hint to where it should be //! inserted and obtains the needed information to realize //! a constant-time node insertion if there is no equivalent node. //! If "hint" is the upper_bound the function has constant time //! complexity (two comparisons in the worst case). //! //! <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, but it is //! amortized constant time if new_node should be inserted immediately before "hint". //! //! <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 (const_node_ptr header, node_ptr hint, const KeyType &key ,KeyNodePtrCompare comp, insert_commit_data &commit_data) { return tree_algorithms::insert_unique_check(header, hint, key, comp, commit_data); } //! <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); rebalance_after_insertion(header, new_value); } //! <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); } /// @cond private: //! <b>Requires</b>: p is a node of a tree. //! //! <b>Effects</b>: Returns true if p is the header of the tree. //! //! <b>Complexity</b>: Constant. //! //! <b>Throws</b>: Nothing. static bool is_header(const_node_ptr p) { return NodeTraits::get_balance(p) == NodeTraits::zero() && tree_algorithms::is_header(p); } static void rebalance_after_erasure(node_ptr header, node_ptr x, node_ptr x_parent) { for (node_ptr root = NodeTraits::get_parent(header); x != root; root = NodeTraits::get_parent(header)) { const balance x_parent_balance = NodeTraits::get_balance(x_parent); if(x_parent_balance == NodeTraits::zero()){ NodeTraits::set_balance(x_parent, (x == NodeTraits::get_right(x_parent) ? NodeTraits::negative() : NodeTraits::positive())); break; // the height didn't change, let's stop here } else if(x_parent_balance == NodeTraits::negative()){ if (x == NodeTraits::get_left(x_parent)) { NodeTraits::set_balance(x_parent, NodeTraits::zero()); // balanced x = x_parent; x_parent = NodeTraits::get_parent(x_parent); } else { // x is right child // a is left child node_ptr a = NodeTraits::get_left(x_parent); BOOST_INTRUSIVE_INVARIANT_ASSERT(a); if (NodeTraits::get_balance(a) == NodeTraits::positive()) { // a MUST have a right child BOOST_INTRUSIVE_INVARIANT_ASSERT(NodeTraits::get_right(a)); rotate_left_right(x_parent, header); x = NodeTraits::get_parent(x_parent); x_parent = NodeTraits::get_parent(x); } else { rotate_right(x_parent, header); x = NodeTraits::get_parent(x_parent); x_parent = NodeTraits::get_parent(x); } // if changed from negative to NodeTraits::positive(), no need to check above if (NodeTraits::get_balance(x) == NodeTraits::positive()){ break; } } } else if(x_parent_balance == NodeTraits::positive()){ if (x == NodeTraits::get_right(x_parent)) { NodeTraits::set_balance(x_parent, NodeTraits::zero()); // balanced x = x_parent; x_parent = NodeTraits::get_parent(x_parent); } else { // x is left child // a is right child node_ptr a = NodeTraits::get_right(x_parent); BOOST_INTRUSIVE_INVARIANT_ASSERT(a); if (NodeTraits::get_balance(a) == NodeTraits::negative()) { // a MUST have then a left child BOOST_INTRUSIVE_INVARIANT_ASSERT(NodeTraits::get_left(a)); rotate_right_left(x_parent, header); x = NodeTraits::get_parent(x_parent); x_parent = NodeTraits::get_parent(x); } else { rotate_left(x_parent, header); x = NodeTraits::get_parent(x_parent); x_parent = NodeTraits::get_parent(x); } // if changed from NodeTraits::positive() to negative, no need to check above if (NodeTraits::get_balance(x) == NodeTraits::negative()){ break; } } } else{ BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached } } } static void rebalance_after_insertion(node_ptr header, node_ptr x) { NodeTraits::set_balance(x, NodeTraits::zero()); // Rebalance. for(node_ptr root = NodeTraits::get_parent(header); x != root; root = NodeTraits::get_parent(header)){ const balance x_parent_balance = NodeTraits::get_balance(NodeTraits::get_parent(x)); if(x_parent_balance == NodeTraits::zero()){ // if x is left, parent will have parent->bal_factor = negative // else, parent->bal_factor = NodeTraits::positive() NodeTraits::set_balance( NodeTraits::get_parent(x) , x == NodeTraits::get_left(NodeTraits::get_parent(x)) ? NodeTraits::negative() : NodeTraits::positive() ); x = NodeTraits::get_parent(x); } else if(x_parent_balance == NodeTraits::positive()){ // if x is a left child, parent->bal_factor = zero if (x == NodeTraits::get_left(NodeTraits::get_parent(x))) NodeTraits::set_balance(NodeTraits::get_parent(x), NodeTraits::zero()); else{ // x is a right child, needs rebalancing if (NodeTraits::get_balance(x) == NodeTraits::negative()) rotate_right_left(NodeTraits::get_parent(x), header); else rotate_left(NodeTraits::get_parent(x), header); } break; } else if(x_parent_balance == NodeTraits::negative()){ // if x is a left child, needs rebalancing if (x == NodeTraits::get_left(NodeTraits::get_parent(x))) { if (NodeTraits::get_balance(x) == NodeTraits::positive()) rotate_left_right(NodeTraits::get_parent(x), header); else rotate_right(NodeTraits::get_parent(x), header); } else NodeTraits::set_balance(NodeTraits::get_parent(x), NodeTraits::zero()); break; } else{ BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached } } } static void left_right_balancing(node_ptr a, node_ptr b, node_ptr c) { // balancing... const balance c_balance = NodeTraits::get_balance(c); const balance zero_balance = NodeTraits::zero(); NodeTraits::set_balance(c, zero_balance); if(c_balance == NodeTraits::negative()){ NodeTraits::set_balance(a, NodeTraits::positive()); NodeTraits::set_balance(b, zero_balance); } else if(c_balance == zero_balance){ NodeTraits::set_balance(a, zero_balance); NodeTraits::set_balance(b, zero_balance); } else if(c_balance == NodeTraits::positive()){ NodeTraits::set_balance(a, zero_balance); NodeTraits::set_balance(b, NodeTraits::negative()); } else{ BOOST_INTRUSIVE_INVARIANT_ASSERT(false); // never reached } } static void rotate_left_right(const node_ptr a, node_ptr hdr) { // | | // // a(-2) c // // / \ / \ // // / \ ==> / \ // // (pos)b [g] b a // // / \ / \ / \ // // [d] c [d] e f [g] // // / \ // // e f // node_ptr b = NodeTraits::get_left(a), c = NodeTraits::get_right(b); tree_algorithms::rotate_left(b, hdr); tree_algorithms::rotate_right(a, hdr); left_right_balancing(a, b, c); } static void rotate_right_left(const node_ptr a, node_ptr hdr) { // | | // // a(pos) c // // / \ / \ // // / \ / \ // // [d] b(neg) ==> a b // // / \ / \ / \ // // c [g] [d] e f [g] // // / \ // // e f // node_ptr b = NodeTraits::get_right(a), c = NodeTraits::get_left(b); tree_algorithms::rotate_right(b, hdr); tree_algorithms::rotate_left(a, hdr); left_right_balancing(b, a, c); } static void rotate_left(const node_ptr x, node_ptr hdr) { const node_ptr y = NodeTraits::get_right(x); tree_algorithms::rotate_left(x, hdr); // reset the balancing factor if (NodeTraits::get_balance(y) == NodeTraits::positive()) { NodeTraits::set_balance(x, NodeTraits::zero()); NodeTraits::set_balance(y, NodeTraits::zero()); } else { // this doesn't happen during insertions NodeTraits::set_balance(x, NodeTraits::positive()); NodeTraits::set_balance(y, NodeTraits::negative()); } } static void rotate_right(const node_ptr x, node_ptr hdr) { const node_ptr y = NodeTraits::get_left(x); tree_algorithms::rotate_right(x, hdr); // reset the balancing factor if (NodeTraits::get_balance(y) == NodeTraits::negative()) { NodeTraits::set_balance(x, NodeTraits::zero()); NodeTraits::set_balance(y, NodeTraits::zero()); } else { // this doesn't happen during insertions NodeTraits::set_balance(x, NodeTraits::negative()); NodeTraits::set_balance(y, NodeTraits::positive()); } } /// @endcond }; } //namespace intrusive } //namespace boost #include <boost/intrusive/detail/config_end.hpp> #endif //BOOST_INTRUSIVE_AVLTREE_ALGORITHMS_HPP