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1 | ///////////////////////////////////////////////////////////////////////////// |
2 | // | |
3 | // (C) Copyright Olaf Krzikalla 2004-2006. | |
4 | // (C) Copyright Ion Gaztanaga 2006-2014 | |
5 | // | |
6 | // Distributed under the Boost Software License, Version 1.0. | |
7 | // (See accompanying file LICENSE_1_0.txt or copy at | |
8 | // http://www.boost.org/LICENSE_1_0.txt) | |
9 | // | |
10 | // See http://www.boost.org/libs/intrusive for documentation. | |
11 | // | |
12 | ///////////////////////////////////////////////////////////////////////////// | |
13 | ||
14 | #ifndef BOOST_INTRUSIVE_LINEAR_SLIST_ALGORITHMS_HPP | |
15 | #define BOOST_INTRUSIVE_LINEAR_SLIST_ALGORITHMS_HPP | |
16 | ||
17 | #include <boost/intrusive/detail/config_begin.hpp> | |
18 | #include <boost/intrusive/intrusive_fwd.hpp> | |
19 | #include <boost/intrusive/detail/common_slist_algorithms.hpp> | |
20 | #include <boost/intrusive/detail/algo_type.hpp> | |
21 | #include <cstddef> | |
22 | #include <boost/intrusive/detail/minimal_pair_header.hpp> //std::pair | |
23 | ||
24 | #if defined(BOOST_HAS_PRAGMA_ONCE) | |
25 | # pragma once | |
26 | #endif | |
27 | ||
28 | namespace boost { | |
29 | namespace intrusive { | |
30 | ||
31 | //! linear_slist_algorithms provides basic algorithms to manipulate nodes | |
32 | //! forming a linear singly linked list. | |
33 | //! | |
34 | //! linear_slist_algorithms is configured with a NodeTraits class, which encapsulates the | |
35 | //! information about the node to be manipulated. NodeTraits must support the | |
36 | //! following interface: | |
37 | //! | |
38 | //! <b>Typedefs</b>: | |
39 | //! | |
40 | //! <tt>node</tt>: The type of the node that forms the linear list | |
41 | //! | |
42 | //! <tt>node_ptr</tt>: A pointer to a node | |
43 | //! | |
44 | //! <tt>const_node_ptr</tt>: A pointer to a const node | |
45 | //! | |
46 | //! <b>Static functions</b>: | |
47 | //! | |
48 | //! <tt>static node_ptr get_next(const_node_ptr n);</tt> | |
49 | //! | |
50 | //! <tt>static void set_next(node_ptr n, node_ptr next);</tt> | |
51 | template<class NodeTraits> | |
52 | class linear_slist_algorithms | |
53 | /// @cond | |
54 | : public detail::common_slist_algorithms<NodeTraits> | |
55 | /// @endcond | |
56 | { | |
57 | /// @cond | |
58 | typedef detail::common_slist_algorithms<NodeTraits> base_t; | |
59 | /// @endcond | |
60 | public: | |
61 | typedef typename NodeTraits::node node; | |
62 | typedef typename NodeTraits::node_ptr node_ptr; | |
63 | typedef typename NodeTraits::const_node_ptr const_node_ptr; | |
64 | typedef NodeTraits node_traits; | |
65 | ||
66 | #if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED) | |
67 | ||
68 | //! <b>Effects</b>: Constructs an non-used list element, putting the next | |
69 | //! pointer to null: | |
70 | //! <tt>NodeTraits::get_next(this_node) == node_ptr()</tt> | |
71 | //! | |
72 | //! <b>Complexity</b>: Constant | |
73 | //! | |
74 | //! <b>Throws</b>: Nothing. | |
75 | static void init(const node_ptr & this_node); | |
76 | ||
77 | //! <b>Requires</b>: this_node must be in a circular list or be an empty circular list. | |
78 | //! | |
79 | //! <b>Effects</b>: Returns true is "this_node" is the only node of a circular list: | |
80 | //! or it's a not inserted node: | |
81 | //! <tt>return node_ptr() == NodeTraits::get_next(this_node) || NodeTraits::get_next(this_node) == this_node</tt> | |
82 | //! | |
83 | //! <b>Complexity</b>: Constant | |
84 | //! | |
85 | //! <b>Throws</b>: Nothing. | |
86 | static bool unique(const_node_ptr this_node); | |
87 | ||
88 | //! <b>Effects</b>: Returns true is "this_node" has the same state as if | |
89 | //! it was inited using "init(node_ptr)" | |
90 | //! | |
91 | //! <b>Complexity</b>: Constant | |
92 | //! | |
93 | //! <b>Throws</b>: Nothing. | |
94 | static bool inited(const_node_ptr this_node); | |
95 | ||
96 | //! <b>Requires</b>: prev_node must be in a circular list or be an empty circular list. | |
97 | //! | |
98 | //! <b>Effects</b>: Unlinks the next node of prev_node from the circular list. | |
99 | //! | |
100 | //! <b>Complexity</b>: Constant | |
101 | //! | |
102 | //! <b>Throws</b>: Nothing. | |
103 | static void unlink_after(const node_ptr & prev_node); | |
104 | ||
105 | //! <b>Requires</b>: prev_node and last_node must be in a circular list | |
106 | //! or be an empty circular list. | |
107 | //! | |
108 | //! <b>Effects</b>: Unlinks the range (prev_node, last_node) from the linear list. | |
109 | //! | |
110 | //! <b>Complexity</b>: Constant | |
111 | //! | |
112 | //! <b>Throws</b>: Nothing. | |
113 | static void unlink_after(const node_ptr & prev_node, const node_ptr & last_node); | |
114 | ||
115 | //! <b>Requires</b>: prev_node must be a node of a linear list. | |
116 | //! | |
117 | //! <b>Effects</b>: Links this_node after prev_node in the linear list. | |
118 | //! | |
119 | //! <b>Complexity</b>: Constant | |
120 | //! | |
121 | //! <b>Throws</b>: Nothing. | |
122 | static void link_after(const node_ptr & prev_node, const node_ptr & this_node); | |
123 | ||
124 | //! <b>Requires</b>: b and e must be nodes of the same linear list or an empty range. | |
125 | //! and p must be a node of a different linear list. | |
126 | //! | |
127 | //! <b>Effects</b>: Removes the nodes from (b, e] range from their linear list and inserts | |
128 | //! them after p in p's linear list. | |
129 | //! | |
130 | //! <b>Complexity</b>: Constant | |
131 | //! | |
132 | //! <b>Throws</b>: Nothing. | |
133 | static void transfer_after(const node_ptr & p, const node_ptr & b, const node_ptr & e); | |
134 | ||
135 | #endif //#if defined(BOOST_INTRUSIVE_DOXYGEN_INVOKED) | |
136 | ||
137 | //! <b>Effects</b>: Constructs an empty list, making this_node the only | |
138 | //! node of the circular list: | |
139 | //! <tt>NodeTraits::get_next(this_node) == this_node</tt>. | |
140 | //! | |
141 | //! <b>Complexity</b>: Constant | |
142 | //! | |
143 | //! <b>Throws</b>: Nothing. | |
144 | BOOST_INTRUSIVE_FORCEINLINE static void init_header(const node_ptr & this_node) | |
145 | { NodeTraits::set_next(this_node, node_ptr ()); } | |
146 | ||
147 | //! <b>Requires</b>: this_node and prev_init_node must be in the same linear list. | |
148 | //! | |
149 | //! <b>Effects</b>: Returns the previous node of this_node in the linear list starting. | |
150 | //! the search from prev_init_node. The first node checked for equality | |
151 | //! is NodeTraits::get_next(prev_init_node). | |
152 | //! | |
153 | //! <b>Complexity</b>: Linear to the number of elements between prev_init_node and this_node. | |
154 | //! | |
155 | //! <b>Throws</b>: Nothing. | |
156 | BOOST_INTRUSIVE_FORCEINLINE static node_ptr get_previous_node(const node_ptr & prev_init_node, const node_ptr & this_node) | |
157 | { return base_t::get_previous_node(prev_init_node, this_node); } | |
158 | ||
159 | //! <b>Requires</b>: this_node must be in a linear list or be an empty linear list. | |
160 | //! | |
161 | //! <b>Effects</b>: Returns the number of nodes in a linear list. If the linear list | |
162 | //! is empty, returns 1. | |
163 | //! | |
164 | //! <b>Complexity</b>: Linear | |
165 | //! | |
166 | //! <b>Throws</b>: Nothing. | |
167 | static std::size_t count(const const_node_ptr & this_node) | |
168 | { | |
169 | std::size_t result = 0; | |
170 | const_node_ptr p = this_node; | |
171 | do{ | |
172 | p = NodeTraits::get_next(p); | |
173 | ++result; | |
174 | } while (p); | |
175 | return result; | |
176 | } | |
177 | ||
178 | //! <b>Requires</b>: this_node and other_node must be nodes inserted | |
179 | //! in linear lists or be empty linear lists. | |
180 | //! | |
181 | //! <b>Effects</b>: Moves all the nodes previously chained after this_node after other_node | |
182 | //! and vice-versa. | |
183 | //! | |
184 | //! <b>Complexity</b>: Constant | |
185 | //! | |
186 | //! <b>Throws</b>: Nothing. | |
187 | static void swap_trailing_nodes(const node_ptr & this_node, const node_ptr & other_node) | |
188 | { | |
189 | node_ptr this_nxt = NodeTraits::get_next(this_node); | |
190 | node_ptr other_nxt = NodeTraits::get_next(other_node); | |
191 | NodeTraits::set_next(this_node, other_nxt); | |
192 | NodeTraits::set_next(other_node, this_nxt); | |
193 | } | |
194 | ||
195 | //! <b>Effects</b>: Reverses the order of elements in the list. | |
196 | //! | |
197 | //! <b>Returns</b>: The new first node of the list. | |
198 | //! | |
199 | //! <b>Throws</b>: Nothing. | |
200 | //! | |
201 | //! <b>Complexity</b>: This function is linear to the contained elements. | |
202 | static node_ptr reverse(const node_ptr & p) | |
203 | { | |
204 | if(!p) return node_ptr(); | |
205 | node_ptr i = NodeTraits::get_next(p); | |
206 | node_ptr first(p); | |
207 | while(i){ | |
208 | node_ptr nxti(NodeTraits::get_next(i)); | |
209 | base_t::unlink_after(p); | |
210 | NodeTraits::set_next(i, first); | |
211 | first = i; | |
212 | i = nxti; | |
213 | } | |
214 | return first; | |
215 | } | |
216 | ||
217 | //! <b>Effects</b>: Moves the first n nodes starting at p to the end of the list. | |
218 | //! | |
219 | //! <b>Returns</b>: A pair containing the new first and last node of the list or | |
220 | //! if there has been any movement, a null pair if n leads to no movement. | |
221 | //! | |
222 | //! <b>Throws</b>: Nothing. | |
223 | //! | |
224 | //! <b>Complexity</b>: Linear to the number of elements plus the number moved positions. | |
225 | static std::pair<node_ptr, node_ptr> move_first_n_backwards(const node_ptr & p, std::size_t n) | |
226 | { | |
227 | std::pair<node_ptr, node_ptr> ret; | |
228 | //Null shift, or count() == 0 or 1, nothing to do | |
229 | if(!n || !p || !NodeTraits::get_next(p)){ | |
230 | return ret; | |
231 | } | |
232 | ||
233 | node_ptr first = p; | |
234 | bool end_found = false; | |
235 | node_ptr new_last = node_ptr(); | |
236 | node_ptr old_last = node_ptr(); | |
237 | ||
238 | //Now find the new last node according to the shift count. | |
239 | //If we find 0 before finding the new last node | |
240 | //unlink p, shortcut the search now that we know the size of the list | |
241 | //and continue. | |
242 | for(std::size_t i = 1; i <= n; ++i){ | |
243 | new_last = first; | |
244 | first = NodeTraits::get_next(first); | |
245 | if(first == node_ptr()){ | |
246 | //Shortcut the shift with the modulo of the size of the list | |
247 | n %= i; | |
248 | if(!n) return ret; | |
249 | old_last = new_last; | |
250 | i = 0; | |
251 | //Unlink p and continue the new first node search | |
252 | first = p; | |
253 | //unlink_after(new_last); | |
254 | end_found = true; | |
255 | } | |
256 | } | |
257 | ||
258 | //If the p has not been found in the previous loop, find it | |
259 | //starting in the new first node and unlink it | |
260 | if(!end_found){ | |
261 | old_last = base_t::get_previous_node(first, node_ptr()); | |
262 | } | |
263 | ||
264 | //Now link p after the new last node | |
265 | NodeTraits::set_next(old_last, p); | |
266 | NodeTraits::set_next(new_last, node_ptr()); | |
267 | ret.first = first; | |
268 | ret.second = new_last; | |
269 | return ret; | |
270 | } | |
271 | ||
272 | //! <b>Effects</b>: Moves the first n nodes starting at p to the beginning of the list. | |
273 | //! | |
274 | //! <b>Returns</b>: A pair containing the new first and last node of the list or | |
275 | //! if there has been any movement, a null pair if n leads to no movement. | |
276 | //! | |
277 | //! <b>Throws</b>: Nothing. | |
278 | //! | |
279 | //! <b>Complexity</b>: Linear to the number of elements plus the number moved positions. | |
280 | static std::pair<node_ptr, node_ptr> move_first_n_forward(const node_ptr & p, std::size_t n) | |
281 | { | |
282 | std::pair<node_ptr, node_ptr> ret; | |
283 | //Null shift, or count() == 0 or 1, nothing to do | |
284 | if(!n || !p || !NodeTraits::get_next(p)) | |
285 | return ret; | |
286 | ||
287 | node_ptr first = p; | |
288 | ||
289 | //Iterate until p is found to know where the current last node is. | |
290 | //If the shift count is less than the size of the list, we can also obtain | |
291 | //the position of the new last node after the shift. | |
292 | node_ptr old_last(first), next_to_it, new_last(p); | |
293 | std::size_t distance = 1; | |
294 | while(!!(next_to_it = node_traits::get_next(old_last))){ | |
295 | if(distance++ > n) | |
296 | new_last = node_traits::get_next(new_last); | |
297 | old_last = next_to_it; | |
298 | } | |
299 | //If the shift was bigger or equal than the size, obtain the equivalent | |
300 | //forward shifts and find the new last node. | |
301 | if(distance <= n){ | |
302 | //Now find the equivalent forward shifts. | |
303 | //Shortcut the shift with the modulo of the size of the list | |
304 | std::size_t new_before_last_pos = (distance - (n % distance))% distance; | |
305 | //If the shift is a multiple of the size there is nothing to do | |
306 | if(!new_before_last_pos) | |
307 | return ret; | |
308 | ||
309 | for( new_last = p | |
310 | ; --new_before_last_pos | |
311 | ; new_last = node_traits::get_next(new_last)){ | |
312 | //empty | |
313 | } | |
314 | } | |
315 | ||
316 | //Get the first new node | |
317 | node_ptr new_first(node_traits::get_next(new_last)); | |
318 | //Now put the old beginning after the old end | |
319 | NodeTraits::set_next(old_last, p); | |
320 | NodeTraits::set_next(new_last, node_ptr()); | |
321 | ret.first = new_first; | |
322 | ret.second = new_last; | |
323 | return ret; | |
324 | } | |
325 | }; | |
326 | ||
327 | /// @cond | |
328 | ||
329 | template<class NodeTraits> | |
330 | struct get_algo<LinearSListAlgorithms, NodeTraits> | |
331 | { | |
332 | typedef linear_slist_algorithms<NodeTraits> type; | |
333 | }; | |
334 | ||
335 | /// @endcond | |
336 | ||
337 | } //namespace intrusive | |
338 | } //namespace boost | |
339 | ||
340 | #include <boost/intrusive/detail/config_end.hpp> | |
341 | ||
342 | #endif //BOOST_INTRUSIVE_LINEAR_SLIST_ALGORITHMS_HPP |