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/////////////////////////////////////////////////////////////////////////////
//
// (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