boost/intrusive/linear_slist_algorithms.hpp
/////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Olaf Krzikalla 2004-2006.
// (C) Copyright Ion Gaztanaga 2006-2014
//
// 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_LINEAR_SLIST_ALGORITHMS_HPP
#define BOOST_INTRUSIVE_LINEAR_SLIST_ALGORITHMS_HPP
#include <boost/intrusive/detail/config_begin.hpp>
#include <boost/intrusive/intrusive_fwd.hpp>
#include <boost/intrusive/detail/common_slist_algorithms.hpp>
#include <boost/intrusive/detail/algo_type.hpp>
#include <cstddef>
#include <boost/intrusive/detail/minimal_pair_header.hpp> //std::pair
#if defined(BOOST_HAS_PRAGMA_ONCE)
# pragma once
#endif
namespace boost {
namespace intrusive {
//! linear_slist_algorithms provides basic algorithms to manipulate nodes
//! forming a linear singly linked list.
//!
//! linear_slist_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 linear 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_next(const_node_ptr n);</tt>
//!
//! <tt>static void set_next(node_ptr n, node_ptr next);</tt>
template<class NodeTraits>
class linear_slist_algorithms
/// @cond
: public detail::common_slist_algorithms<NodeTraits>
/// @endcond
{
/// @cond
typedef detail::common_slist_algorithms<NodeTraits> base_t;
/// @endcond
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;
#if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED)
//! <b>Effects</b>: Constructs an non-used list element, putting the next
//! pointer to null:
//! <tt>NodeTraits::get_next(this_node) == node_ptr()</tt>
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
static void init(const node_ptr & 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:
//! or it's a not inserted node:
//! <tt>return node_ptr() == NodeTraits::get_next(this_node) || NodeTraits::get_next(this_node) == this_node</tt>
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
static bool unique(const_node_ptr this_node);
//! <b>Effects</b>: Returns true is "this_node" has the same state as if
//! it was inited using "init(node_ptr)"
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
static bool inited(const_node_ptr this_node);
//! <b>Requires</b>: prev_node must be in a circular list or be an empty circular list.
//!
//! <b>Effects</b>: Unlinks the next node of prev_node from the circular list.
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
static void unlink_after(const node_ptr & prev_node);
//! <b>Requires</b>: prev_node and last_node must be in a circular list
//! or be an empty circular list.
//!
//! <b>Effects</b>: Unlinks the range (prev_node, last_node) from the linear list.
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
static void unlink_after(const node_ptr & prev_node, const node_ptr & last_node);
//! <b>Requires</b>: prev_node must be a node of a linear list.
//!
//! <b>Effects</b>: Links this_node after prev_node in the linear list.
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
static void link_after(const node_ptr & prev_node, const node_ptr & this_node);
//! <b>Requires</b>: b and e must be nodes of the same linear list or an empty range.
//! and p must be a node of a different linear list.
//!
//! <b>Effects</b>: Removes the nodes from (b, e] range from their linear list and inserts
//! them after p in p's linear list.
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
static void transfer_after(const node_ptr & p, const node_ptr & b, const node_ptr & e);
#endif //#if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED)
//! <b>Effects</b>: Constructs an empty list, making this_node the only
//! node of the circular list:
//! <tt>NodeTraits::get_next(this_node) == this_node</tt>.
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
BOOST_INTRUSIVE_FORCEINLINE static void init_header(const node_ptr & this_node)
{ NodeTraits::set_next(this_node, node_ptr ()); }
//! <b>Requires</b>: this_node and prev_init_node must be in the same linear list.
//!
//! <b>Effects</b>: Returns the previous node of this_node in the linear list starting.
//! the search from prev_init_node. The first node checked for equality
//! is NodeTraits::get_next(prev_init_node).
//!
//! <b>Complexity</b>: Linear to the number of elements between prev_init_node and this_node.
//!
//! <b>Throws</b>: Nothing.
BOOST_INTRUSIVE_FORCEINLINE static node_ptr get_previous_node(const node_ptr & prev_init_node, const node_ptr & this_node)
{ return base_t::get_previous_node(prev_init_node, this_node); }
//! <b>Requires</b>: this_node must be in a linear list or be an empty linear list.
//!
//! <b>Effects</b>: Returns the number of nodes in a linear list. If the linear list
//! is empty, returns 1.
//!
//! <b>Complexity</b>: Linear
//!
//! <b>Throws</b>: Nothing.
static std::size_t count(const 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);
return result;
}
//! <b>Requires</b>: this_node and other_node must be nodes inserted
//! in linear lists or be empty linear lists.
//!
//! <b>Effects</b>: Moves all the nodes previously chained after this_node after other_node
//! and vice-versa.
//!
//! <b>Complexity</b>: Constant
//!
//! <b>Throws</b>: Nothing.
static void swap_trailing_nodes(node_ptr this_node, node_ptr other_node)
{
node_ptr this_nxt = NodeTraits::get_next(this_node);
node_ptr other_nxt = NodeTraits::get_next(other_node);
NodeTraits::set_next(this_node, other_nxt);
NodeTraits::set_next(other_node, this_nxt);
}
//! <b>Effects</b>: Reverses the order of elements in the list.
//!
//! <b>Returns</b>: The new first node of the list.
//!
//! <b>Throws</b>: Nothing.
//!
//! <b>Complexity</b>: This function is linear to the contained elements.
static node_ptr reverse(node_ptr p)
{
if(!p) return node_ptr();
node_ptr i = NodeTraits::get_next(p);
node_ptr first(p);
while(i){
node_ptr nxti(NodeTraits::get_next(i));
base_t::unlink_after(p);
NodeTraits::set_next(i, first);
first = i;
i = nxti;
}
return first;
}
//! <b>Effects</b>: Moves the first n nodes starting at p to the end of the list.
//!
//! <b>Returns</b>: A pair containing the new first and last node of the list or
//! if there has been any movement, a null pair if n leads to no movement.
//!
//! <b>Throws</b>: Nothing.
//!
//! <b>Complexity</b>: Linear to the number of elements plus the number moved positions.
static std::pair<node_ptr, node_ptr> move_first_n_backwards(node_ptr p, std::size_t n)
{
std::pair<node_ptr, node_ptr> ret;
//Null shift, or count() == 0 or 1, nothing to do
if(!n || !p || !NodeTraits::get_next(p)){
return ret;
}
node_ptr first = p;
bool end_found = false;
node_ptr new_last = node_ptr();
node_ptr old_last = node_ptr();
//Now find the new last node according to the shift count.
//If we find 0 before finding the new last node
//unlink p, shortcut the search now that we know the size of the list
//and continue.
for(std::size_t i = 1; i <= n; ++i){
new_last = first;
first = NodeTraits::get_next(first);
if(first == node_ptr()){
//Shortcut the shift with the modulo of the size of the list
n %= i;
if(!n) return ret;
old_last = new_last;
i = 0;
//Unlink p and continue the new first node search
first = p;
//unlink_after(new_last);
end_found = true;
}
}
//If the p has not been found in the previous loop, find it
//starting in the new first node and unlink it
if(!end_found){
old_last = base_t::get_previous_node(first, node_ptr());
}
//Now link p after the new last node
NodeTraits::set_next(old_last, p);
NodeTraits::set_next(new_last, node_ptr());
ret.first = first;
ret.second = new_last;
return ret;
}
//! <b>Effects</b>: Moves the first n nodes starting at p to the beginning of the list.
//!
//! <b>Returns</b>: A pair containing the new first and last node of the list or
//! if there has been any movement, a null pair if n leads to no movement.
//!
//! <b>Throws</b>: Nothing.
//!
//! <b>Complexity</b>: Linear to the number of elements plus the number moved positions.
static std::pair<node_ptr, node_ptr> move_first_n_forward(node_ptr p, std::size_t n)
{
std::pair<node_ptr, node_ptr> ret;
//Null shift, or count() == 0 or 1, nothing to do
if(!n || !p || !NodeTraits::get_next(p))
return ret;
node_ptr first = p;
//Iterate until p is found to know where the current last node is.
//If the shift count is less than the size of the list, we can also obtain
//the position of the new last node after the shift.
node_ptr old_last(first), next_to_it, new_last(p);
std::size_t distance = 1;
while(!!(next_to_it = node_traits::get_next(old_last))){
if(distance++ > n)
new_last = node_traits::get_next(new_last);
old_last = next_to_it;
}
//If the shift was bigger or equal than the size, obtain the equivalent
//forward shifts and find the new last node.
if(distance <= n){
//Now find the equivalent forward shifts.
//Shortcut the shift with the modulo of the size of the list
std::size_t new_before_last_pos = (distance - (n % distance))% distance;
//If the shift is a multiple of the size there is nothing to do
if(!new_before_last_pos)
return ret;
for( new_last = p
; --new_before_last_pos
; new_last = node_traits::get_next(new_last)){
//empty
}
}
//Get the first new node
node_ptr new_first(node_traits::get_next(new_last));
//Now put the old beginning after the old end
NodeTraits::set_next(old_last, p);
NodeTraits::set_next(new_last, node_ptr());
ret.first = new_first;
ret.second = new_last;
return ret;
}
};
/// @cond
template<class NodeTraits>
struct get_algo<LinearSListAlgorithms, NodeTraits>
{
typedef linear_slist_algorithms<NodeTraits> type;
};
/// @endcond
} //namespace intrusive
} //namespace boost
#include <boost/intrusive/detail/config_end.hpp>
#endif //BOOST_INTRUSIVE_LINEAR_SLIST_ALGORITHMS_HPP