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Class template circular_list_algorithms

boost::intrusive::circular_list_algorithms

Synopsis

// In header: <boost/intrusive/circular_list_algorithms.hpp>

template<typename NodeTraits> 
class circular_list_algorithms {
public:
  // types
  typedef NodeTraits::node           node;          
  typedef NodeTraits::node_ptr       node_ptr;      
  typedef NodeTraits::const_node_ptr const_node_ptr;
  typedef NodeTraits                 node_traits;   

  // public static functions
  static void init(const node_ptr &);
  static bool inited(const const_node_ptr &);
  static void init_header(const node_ptr &);
  static bool unique(const const_node_ptr &);
  static std::size_t count(const const_node_ptr &);
  static node_ptr unlink(const node_ptr &);
  static void unlink(const node_ptr &, const node_ptr &);
  static void link_before(const node_ptr &, const node_ptr &);
  static void link_after(const node_ptr &, const node_ptr &);
  static void swap_nodes(const node_ptr &, const node_ptr &);
  static void transfer(const node_ptr &, const node_ptr &, const node_ptr &);
  static void transfer(const node_ptr &, const node_ptr &);
  static void reverse(const node_ptr &);
  static void move_backwards(const node_ptr &, std::size_t);
  static void move_forward(const node_ptr &, std::size_t);

  // private static functions
  static void swap_prev(const node_ptr &, const node_ptr &);
  static void swap_next(const node_ptr &, const node_ptr &);
};

Description

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:

Typedefs:

node: The type of the node that forms the circular list

node_ptr: A pointer to a node

const_node_ptr: A pointer to a const node

Static functions:

static node_ptr get_previous(const_node_ptr n);

static void set_previous(node_ptr n, node_ptr prev);

static node_ptr get_next(const_node_ptr n);

static void set_next(node_ptr n, node_ptr next);

circular_list_algorithms public static functions

  1. static void init(const node_ptr & this_node);

    Effects: Constructs an non-used list element, so that inited(this_node) == true

    Complexity: Constant

    Throws: Nothing.

  2. static bool inited(const const_node_ptr & this_node);

    Effects: Returns true is "this_node" is in a non-used state as if it was initialized by the "init" function.

    Complexity: Constant

    Throws: Nothing.

  3. static void init_header(const node_ptr & this_node);

    Effects: Constructs an empty list, making this_node the only node of the circular list: NodeTraits::get_next(this_node) == NodeTraits::get_previous(this_node) == this_node.

    Complexity: Constant

    Throws: Nothing.

  4. static bool unique(const const_node_ptr & this_node);

    Requires: this_node must be in a circular list or be an empty circular list.

    Effects: Returns true is "this_node" is the only node of a circular list: return NodeTraits::get_next(this_node) == this_node

    Complexity: Constant

    Throws: Nothing.

  5. static std::size_t count(const const_node_ptr & this_node);

    Requires: this_node must be in a circular list or be an empty circular list.

    Effects: Returns the number of nodes in a circular list. If the circular list is empty, returns 1.

    Complexity: Linear

    Throws: Nothing.

  6. static node_ptr unlink(const node_ptr & this_node);

    Requires: this_node must be in a circular list or be an empty circular list.

    Effects: Unlinks the node from the circular list.

    Complexity: Constant

    Throws: Nothing.

  7. static void unlink(const node_ptr & b, const node_ptr & e);

    Requires: b and e must be nodes of the same circular list or an empty range.

    Effects: Unlinks the node [b, e) from the circular list.

    Complexity: Constant

    Throws: Nothing.

  8. static void link_before(const node_ptr & nxt_node, const node_ptr & this_node);

    Requires: nxt_node must be a node of a circular list.

    Effects: Links this_node before nxt_node in the circular list.

    Complexity: Constant

    Throws: Nothing.

  9. static void link_after(const node_ptr & prev_node, const node_ptr & this_node);

    Requires: prev_node must be a node of a circular list.

    Effects: Links this_node after prev_node in the circular list.

    Complexity: Constant

    Throws: Nothing.

  10. static void swap_nodes(const node_ptr & this_node, 
                           const node_ptr & other_node);
  11. static void transfer(const node_ptr & p, const node_ptr & b, 
                         const node_ptr & e);

    Requires: 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 Effects: Removes the nodes from [b, e) range from their circular list and inserts them before p in p's circular list.

    Complexity: Constant

    Throws: Nothing.

  12. static void transfer(const node_ptr & p, const node_ptr & i);

    Requires: i must a node of a circular list and p must be a node of a different circular list.

    Effects: 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.

    Complexity: Constant

    Throws: Nothing.

  13. static void reverse(const node_ptr & p);

    Effects: Reverses the order of elements in the list.

    Throws: Nothing.

    Complexity: This function is linear time.

  14. static void move_backwards(const node_ptr & p, std::size_t n);

    Effects: Moves the node p n positions towards the end of the list.

    Throws: Nothing.

    Complexity: Linear to the number of moved positions.

  15. static void move_forward(const node_ptr & p, std::size_t n);

    Effects: Moves the node p n positions towards the beginning of the list.

    Throws: Nothing.

    Complexity: Linear to the number of moved positions.

circular_list_algorithms private static functions

  1. static void swap_prev(const node_ptr & this_node, const node_ptr & other_node);

    Requires: this_node and other_node must be nodes inserted in circular lists or be empty circular lists.

    Effects: 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.

    Complexity: Constant

    Throws: Nothing.

  2. static void swap_next(const node_ptr & this_node, const node_ptr & other_node);

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