| ///////////////////////////////////////////////////////////////////////////// |
| // |
| // (C) Copyright Olaf Krzikalla 2004-2006. |
| // (C) Copyright Ion Gaztanaga 2006-2009 |
| // |
| // 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_CIRCULAR_LIST_ALGORITHMS_HPP |
| #define BOOST_INTRUSIVE_CIRCULAR_LIST_ALGORITHMS_HPP |
| |
| #include <boost/intrusive/detail/config_begin.hpp> |
| #include <boost/intrusive/intrusive_fwd.hpp> |
| #include <cstddef> |
| |
| namespace boost { |
| namespace intrusive { |
| |
| //! circular_list_algorithms provides basic algorithms to manipulate nodes |
| //! forming a circular doubly linked list. An empty circular list is formed by a node |
| //! whose pointers point to itself. |
| //! |
| //! circular_list_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_previous(const_node_ptr n);</tt> |
| //! |
| //! <tt>static void set_previous(node_ptr n, node_ptr prev);</tt> |
| //! |
| //! <tt>static node_ptr get_next(const_node_ptr n);</tt> |
| //! |
| //! <tt>static void set_next(node_ptr n, node_ptr next);</tt> |
| template<class NodeTraits> |
| class circular_list_algorithms |
| { |
| public: |
| typedef typename NodeTraits::node node; |
| typedef typename NodeTraits::node_ptr node_ptr; |
| typedef typename NodeTraits::const_node_ptr const_node_ptr; |
| typedef NodeTraits node_traits; |
| |
| //! <b>Effects</b>: Constructs an non-used list element, so that |
| //! inited(this_node) == true |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static void init(node_ptr this_node) |
| { |
| NodeTraits::set_next(this_node, node_ptr(0)); |
| NodeTraits::set_previous(this_node, node_ptr(0)); |
| } |
| |
| //! <b>Effects</b>: Returns true is "this_node" is in a non-used state |
| //! as if it was initialized by the "init" function. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static bool inited(const_node_ptr this_node) |
| { return !NodeTraits::get_next(this_node); } |
| |
| //! <b>Effects</b>: Constructs an empty list, making this_node the only |
| //! node of the circular list: |
| //! <tt>NodeTraits::get_next(this_node) == NodeTraits::get_previous(this_node) |
| //! == this_node</tt>. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static void init_header(node_ptr this_node) |
| { |
| NodeTraits::set_next(this_node, this_node); |
| NodeTraits::set_previous(this_node, this_node); |
| } |
| |
| |
| //! <b>Requires</b>: this_node must be in a circular list or be an empty circular list. |
| //! |
| //! <b>Effects</b>: Returns true is "this_node" is the only node of a circular list: |
| //! <tt>return NodeTraits::get_next(this_node) == this_node</tt> |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static bool unique(const_node_ptr this_node) |
| { |
| node_ptr next = NodeTraits::get_next(this_node); |
| return !next || next == this_node; |
| } |
| |
| //! <b>Requires</b>: this_node must be in a circular list or be an empty circular list. |
| //! |
| //! <b>Effects</b>: Returns the number of nodes in a circular list. If the circular list |
| //! is empty, returns 1. |
| //! |
| //! <b>Complexity</b>: Linear |
| //! |
| //! <b>Throws</b>: Nothing. |
| static std::size_t count(const_node_ptr this_node) |
| { |
| std::size_t result = 0; |
| const_node_ptr p = this_node; |
| do{ |
| p = NodeTraits::get_next(p); |
| ++result; |
| }while (p != this_node); |
| return result; |
| } |
| |
| //! <b>Requires</b>: this_node must be in a circular list or be an empty circular list. |
| //! |
| //! <b>Effects</b>: Unlinks the node from the circular list. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static node_ptr unlink(node_ptr this_node) |
| { |
| if(NodeTraits::get_next(this_node)){ |
| node_ptr next(NodeTraits::get_next(this_node)); |
| node_ptr prev(NodeTraits::get_previous(this_node)); |
| NodeTraits::set_next(prev, next); |
| NodeTraits::set_previous(next, prev); |
| return next; |
| } |
| else{ |
| return this_node; |
| } |
| } |
| |
| //! <b>Requires</b>: b and e must be nodes of the same circular list or an empty range. |
| //! |
| //! <b>Effects</b>: Unlinks the node [b, e) from the circular list. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static void unlink(node_ptr b, node_ptr e) |
| { |
| if (b != e) { |
| node_ptr prevb(NodeTraits::get_previous(b)); |
| NodeTraits::set_previous(e, prevb); |
| NodeTraits::set_next(prevb, e); |
| } |
| } |
| |
| //! <b>Requires</b>: nxt_node must be a node of a circular list. |
| //! |
| //! <b>Effects</b>: Links this_node before nxt_node in the circular list. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static void link_before(node_ptr nxt_node, node_ptr this_node) |
| { |
| node_ptr prev(NodeTraits::get_previous(nxt_node)); |
| NodeTraits::set_previous(this_node, prev); |
| NodeTraits::set_next(prev, this_node); |
| NodeTraits::set_previous(nxt_node, this_node); |
| NodeTraits::set_next(this_node, nxt_node); |
| } |
| |
| //! <b>Requires</b>: prev_node must be a node of a circular list. |
| //! |
| //! <b>Effects</b>: Links this_node after prev_node in the circular list. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static void link_after(node_ptr prev_node, node_ptr this_node) |
| { |
| node_ptr next(NodeTraits::get_next(prev_node)); |
| NodeTraits::set_previous(this_node, prev_node); |
| NodeTraits::set_next(this_node, next); |
| NodeTraits::set_previous(next, this_node); |
| NodeTraits::set_next(prev_node, this_node); |
| } |
| |
| //! <b>Requires</b>: this_node and other_node must be nodes inserted |
| //! in circular lists or be empty circular lists. |
| //! |
| //! <b>Effects</b>: Swaps the position of the nodes: this_node is inserted in |
| //! other_nodes position in the second circular list and the other_node is inserted |
| //! in this_node's position in the first circular list. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| /* |
| static void swap_nodes(node_ptr this_node, node_ptr other_node) |
| { |
| |
| if (other_node == this_node) |
| return; |
| bool empty1 = unique(this_node); |
| bool empty2 = unique(other_node); |
| |
| node_ptr next_this(NodeTraits::get_next(this_node)); |
| node_ptr prev_this(NodeTraits::get_previous(this_node)); |
| node_ptr next_other(NodeTraits::get_next(other_node)); |
| node_ptr prev_other(NodeTraits::get_previous(other_node)); |
| |
| //Do the swap |
| NodeTraits::set_next(this_node, next_other); |
| NodeTraits::set_next(other_node, next_this); |
| |
| NodeTraits::set_previous(this_node, prev_other); |
| NodeTraits::set_previous(other_node, prev_this); |
| |
| if (empty2){ |
| init(this_node); |
| } |
| else{ |
| NodeTraits::set_next(prev_other, this_node); |
| NodeTraits::set_previous(next_other, this_node); |
| } |
| if (empty1){ |
| init(other_node); |
| } |
| else{ |
| NodeTraits::set_next(prev_this, other_node); |
| NodeTraits::set_previous(next_this, other_node); |
| } |
| } |
| */ |
| |
| //Watanabe version |
| private: |
| static void swap_prev(node_ptr this_node, node_ptr other_node) |
| { |
| node_ptr temp(NodeTraits::get_previous(this_node)); |
| NodeTraits::set_previous(this_node, NodeTraits::get_previous(other_node)); |
| NodeTraits::set_previous(other_node, temp); |
| } |
| static void swap_next(node_ptr this_node, node_ptr other_node) |
| { |
| node_ptr temp(NodeTraits::get_next(this_node)); |
| NodeTraits::set_next(this_node, NodeTraits::get_next(other_node)); |
| NodeTraits::set_next(other_node, temp); |
| } |
| |
| public: |
| static void swap_nodes(node_ptr this_node, node_ptr other_node) |
| { |
| if (other_node == this_node) |
| return; |
| bool this_inited = inited(this_node); |
| bool other_inited = inited(other_node); |
| if(this_inited){ |
| init_header(this_node); |
| } |
| if(other_inited){ |
| init_header(other_node); |
| } |
| |
| node_ptr next_this(NodeTraits::get_next(this_node)); |
| node_ptr prev_this(NodeTraits::get_previous(this_node)); |
| node_ptr next_other(NodeTraits::get_next(other_node)); |
| node_ptr prev_other(NodeTraits::get_previous(other_node)); |
| //these first two swaps must happen before the other two |
| swap_prev(next_this, next_other); |
| swap_next(prev_this, prev_other); |
| swap_next(this_node, other_node); |
| swap_prev(this_node, other_node); |
| |
| if(this_inited){ |
| init(other_node); |
| } |
| if(other_inited){ |
| init(this_node); |
| } |
| } |
| |
| //! <b>Requires</b>: b and e must be nodes of the same circular list or an empty range. |
| //! and p must be a node of a different circular list or may not be an iterator in |
| // [b, e). |
| //! |
| //! <b>Effects</b>: Removes the nodes from [b, e) range from their circular list and inserts |
| //! them before p in p's circular list. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static void transfer(node_ptr p, node_ptr b, node_ptr e) |
| { |
| if (b != e) { |
| node_ptr prev_p(NodeTraits::get_previous(p)); |
| node_ptr prev_b(NodeTraits::get_previous(b)); |
| node_ptr prev_e(NodeTraits::get_previous(e)); |
| NodeTraits::set_next(prev_e, p); |
| NodeTraits::set_previous(p, prev_e); |
| NodeTraits::set_next(prev_b, e); |
| NodeTraits::set_previous(e, prev_b); |
| NodeTraits::set_next(prev_p, b); |
| NodeTraits::set_previous(b, prev_p); |
| } |
| } |
| |
| //! <b>Requires</b>: i must a node of a circular list |
| //! and p must be a node of a different circular list. |
| //! |
| //! <b>Effects</b>: Removes the node i from its circular list and inserts |
| //! it before p in p's circular list. |
| //! If p == i or p == NodeTraits::get_next(i), this function is a null operation. |
| //! |
| //! <b>Complexity</b>: Constant |
| //! |
| //! <b>Throws</b>: Nothing. |
| static void transfer(node_ptr p, node_ptr i) |
| { |
| node_ptr n(NodeTraits::get_next(i)); |
| if(n != p && i != p){ |
| node_ptr prev_p(NodeTraits::get_previous(p)); |
| node_ptr prev_i(NodeTraits::get_previous(i)); |
| NodeTraits::set_next(prev_p, i); |
| NodeTraits::set_previous(i, prev_p); |
| NodeTraits::set_next(i, p); |
| NodeTraits::set_previous(p, i); |
| NodeTraits::set_previous(n, prev_i); |
| NodeTraits::set_next(prev_i, n); |
| |
| } |
| } |
| |
| //! <b>Effects</b>: Reverses the order of elements in the list. |
| //! |
| //! <b>Throws</b>: Nothing. |
| //! |
| //! <b>Complexity</b>: This function is linear time. |
| static void reverse(node_ptr p) |
| { |
| node_ptr f(NodeTraits::get_next(p)); |
| node_ptr i(NodeTraits::get_next(f)), e(p); |
| |
| while(i != e) { |
| node_ptr n = i; |
| i = NodeTraits::get_next(i); |
| transfer(f, n, i); |
| f = n; |
| } |
| } |
| |
| //! <b>Effects</b>: Moves the node p n positions towards the end of the list. |
| //! |
| //! <b>Throws</b>: Nothing. |
| //! |
| //! <b>Complexity</b>: Linear to the number of moved positions. |
| static void move_backwards(node_ptr p, std::size_t n) |
| { |
| //Null shift, nothing to do |
| if(!n) return; |
| node_ptr first = NodeTraits::get_next(p); |
| //size() == 0 or 1, nothing to do |
| if(first == NodeTraits::get_previous(p)) return; |
| unlink(p); |
| //Now get the new first node |
| while(n--){ |
| first = NodeTraits::get_next(first); |
| } |
| link_before(first, p); |
| } |
| |
| //! <b>Effects</b>: Moves the node p n positions towards the beginning of the list. |
| //! |
| //! <b>Throws</b>: Nothing. |
| //! |
| //! <b>Complexity</b>: Linear to the number of moved positions. |
| static void move_forward(node_ptr p, std::size_t n) |
| { |
| //Null shift, nothing to do |
| if(!n) return; |
| node_ptr last = NodeTraits::get_previous(p); |
| //size() == 0 or 1, nothing to do |
| if(last == NodeTraits::get_next(p)) return; |
| |
| unlink(p); |
| //Now get the new last node |
| while(n--){ |
| last = NodeTraits::get_previous(last); |
| } |
| link_after(last, p); |
| } |
| }; |
| |
| } //namespace intrusive |
| } //namespace boost |
| |
| #include <boost/intrusive/detail/config_end.hpp> |
| |
| #endif //BOOST_INTRUSIVE_CIRCULAR_LIST_ALGORITHMS_HPP |