1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28 /**
29 * \file linked_list.h
30 * \brief Linked list implementation.
31 * \details Also provides several low-level functions for custom linked list implementations.
32 * \author Mike Becker
33 * \author Olaf Wintermann
34 * \version 3.0
35 * \copyright 2-Clause BSD License
36 */
37
38 #ifndef UCX_LINKED_LIST_H
39 #define UCX_LINKED_LIST_H
40
41 #include "common.h"
42 #include "list.h"
43
44 #ifdef __cplusplus
45 extern "C" {
46 #endif
47
48 /**
49 * Set this flag to true, if you want to disable the use of SBO for
50 * linked list swap operations.
51 */
52 extern bool CX_DISABLE_LINKED_LIST_SWAP_SBO;
53
54 /**
55 * Allocates a linked list for storing elements with \p item_size bytes each.
56 *
57 * If \p item_size is CX_STORE_POINTERS, the created list will be created as if
58 * cxListStorePointers() was called immediately after creation.
59 *
60 * @param allocator the allocator for allocating the list nodes
61 * (if \c NULL the cxDefaultAllocator will be used)
62 * @param comparator the comparator for the elements
63 * (if \c NULL sort and find functions will not work)
64 * @param item_size the size of each element in bytes
65 * @return the created list
66 */
67 CxList *cxLinkedListCreate(
68 CxAllocator const *allocator,
69 cx_compare_func comparator,
70 size_t item_size
71 );
72
73 /**
74 * Allocates a linked list for storing elements with \p item_size bytes each.
75 *
76 * The list will use cxDefaultAllocator and no comparator function. If you want
77 * to call functions that need a comparator, you must either set one immediately
78 * after list creation or use cxLinkedListCreate().
79 *
80 * If \p item_size is CX_STORE_POINTERS, the created list will be created as if
81 * cxListStorePointers() was called immediately after creation.
82 *
83 * @param item_size the size of each element in bytes
84 * @return the created list
85 */
86 #define cxLinkedListCreateSimple(item_size) \
87 cxLinkedListCreate(NULL, NULL, item_size)
88
89 /**
90 * Finds the node at a certain index.
91 *
92 * This function can be used to start at an arbitrary position within the list.
93 * If the search index is large than the start index, \p loc_advance must denote
94 * the location of some sort of \c next pointer (i.e. a pointer to the next node).
95 * But it is also possible that the search index is smaller than the start index
96 * (e.g. in cases where traversing a list backwards is faster) in which case
97 * \p loc_advance must denote the location of some sort of \c prev pointer
98 * (i.e. a pointer to the previous node).
99 *
100 * @param start a pointer to the start node
101 * @param start_index the start index
102 * @param loc_advance the location of the pointer to advance
103 * @param index the search index
104 * @return the node found at the specified index
105 */
106 void *cx_linked_list_at(
107 void const *start,
108 size_t start_index,
109 ptrdiff_t loc_advance,
110 size_t index
111 ) __attribute__((__nonnull__));
112
113 /**
114 * Finds the index of an element within a linked list.
115 *
116 * @param start a pointer to the start node
117 * @param loc_advance the location of the pointer to advance
118 * @param loc_data the location of the \c data pointer within your node struct
119 * @param cmp_func a compare function to compare \p elem against the node data
120 * @param elem a pointer to the element to find
121 * @return the index of the element or a negative value if it could not be found
122 */
123 ssize_t cx_linked_list_find(
124 void const *start,
125 ptrdiff_t loc_advance,
126 ptrdiff_t loc_data,
127 cx_compare_func cmp_func,
128 void const *elem
129 ) __attribute__((__nonnull__));
130
131 /**
132 * Finds the first node in a linked list.
133 *
134 * The function starts with the pointer denoted by \p node and traverses the list
135 * along a prev pointer whose location within the node struct is
136 * denoted by \p loc_prev.
137 *
138 * @param node a pointer to a node in the list
139 * @param loc_prev the location of the \c prev pointer
140 * @return a pointer to the first node
141 */
142 void *cx_linked_list_first(
143 void const *node,
144 ptrdiff_t loc_prev
145 ) __attribute__((__nonnull__));
146
147 /**
148 * Finds the last node in a linked list.
149 *
150 * The function starts with the pointer denoted by \p node and traverses the list
151 * along a next pointer whose location within the node struct is
152 * denoted by \p loc_next.
153 *
154 * @param node a pointer to a node in the list
155 * @param loc_next the location of the \c next pointer
156 * @return a pointer to the last node
157 */
158 void *cx_linked_list_last(
159 void const *node,
160 ptrdiff_t loc_next
161 ) __attribute__((__nonnull__));
162
163 /**
164 * Finds the predecessor of a node in case it is not linked.
165 *
166 * \remark If \p node is not contained in the list starting with \p begin, the behavior is undefined.
167 *
168 * @param begin the node where to start the search
169 * @param loc_next the location of the \c next pointer
170 * @param node the successor of the node to find
171 * @return the node or \c NULL if \p node has no predecessor
172 */
173 void *cx_linked_list_prev(
174 void const *begin,
175 ptrdiff_t loc_next,
176 void const *node
177 ) __attribute__((__nonnull__));
178
179 /**
180 * Adds a new node to a linked list.
181 * The node must not be part of any list already.
182 *
183 * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
184 *
185 * @param begin a pointer to the begin node pointer (if your list has one)
186 * @param end a pointer to the end node pointer (if your list has one)
187 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
188 * @param loc_next the location of a \c next pointer within your node struct (required)
189 * @param new_node a pointer to the node that shall be appended
190 */
191 void cx_linked_list_add(
192 void **begin,
193 void **end,
194 ptrdiff_t loc_prev,
195 ptrdiff_t loc_next,
196 void *new_node
197 ) __attribute__((__nonnull__(5)));
198
199 /**
200 * Prepends a new node to a linked list.
201 * The node must not be part of any list already.
202 *
203 * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
204 *
205 * @param begin a pointer to the begin node pointer (if your list has one)
206 * @param end a pointer to the end node pointer (if your list has one)
207 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
208 * @param loc_next the location of a \c next pointer within your node struct (required)
209 * @param new_node a pointer to the node that shall be prepended
210 */
211 void cx_linked_list_prepend(
212 void **begin,
213 void **end,
214 ptrdiff_t loc_prev,
215 ptrdiff_t loc_next,
216 void *new_node
217 ) __attribute__((__nonnull__(5)));
218
219 /**
220 * Links two nodes.
221 *
222 * @param left the new predecessor of \p right
223 * @param right the new successor of \p left
224 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
225 * @param loc_next the location of a \c next pointer within your node struct (required)
226 */
227 void cx_linked_list_link(
228 void *left,
229 void *right,
230 ptrdiff_t loc_prev,
231 ptrdiff_t loc_next
232 ) __attribute__((__nonnull__));
233
234 /**
235 * Unlinks two nodes.
236 *
237 * If right is not the successor of left, the behavior is undefined.
238 *
239 * @param left the predecessor of \p right
240 * @param right the successor of \p left
241 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
242 * @param loc_next the location of a \c next pointer within your node struct (required)
243 */
244 void cx_linked_list_unlink(
245 void *left,
246 void *right,
247 ptrdiff_t loc_prev,
248 ptrdiff_t loc_next
249 ) __attribute__((__nonnull__));
250
251 /**
252 * Inserts a new node after a given node of a linked list.
253 * The new node must not be part of any list already.
254 *
255 * \note If you specify \c NULL as the \p node to insert after, this function needs either the \p begin or
256 * the \p end pointer to determine the start of the list. Then the new node will be prepended to the list.
257 *
258 * @param begin a pointer to the begin node pointer (if your list has one)
259 * @param end a pointer to the end node pointer (if your list has one)
260 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
261 * @param loc_next the location of a \c next pointer within your node struct (required)
262 * @param node the node after which to insert (\c NULL if you want to prepend the node to the list)
263 * @param new_node a pointer to the node that shall be prepended
264 */
265 void cx_linked_list_insert(
266 void **begin,
267 void **end,
268 ptrdiff_t loc_prev,
269 ptrdiff_t loc_next,
270 void *node,
271 void *new_node
272 ) __attribute__((__nonnull__(6)));
273
274 /**
275 * Inserts a chain of nodes after a given node of a linked list.
276 * The chain must not be part of any list already.
277 *
278 * If you do not explicitly specify the end of the chain, it will be determined by traversing
279 * the \c next pointer.
280 *
281 * \note If you specify \c NULL as the \p node to insert after, this function needs either the \p begin or
282 * the \p end pointer to determine the start of the list. If only the \p end pointer is specified, you also need
283 * to provide a valid \p loc_prev location.
284 * Then the chain will be prepended to the list.
285 *
286 * @param begin a pointer to the begin node pointer (if your list has one)
287 * @param end a pointer to the end node pointer (if your list has one)
288 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
289 * @param loc_next the location of a \c next pointer within your node struct (required)
290 * @param node the node after which to insert (\c NULL to prepend the chain to the list)
291 * @param insert_begin a pointer to the first node of the chain that shall be inserted
292 * @param insert_end a pointer to the last node of the chain (or NULL if the last node shall be determined)
293 */
294 void cx_linked_list_insert_chain(
295 void **begin,
296 void **end,
297 ptrdiff_t loc_prev,
298 ptrdiff_t loc_next,
299 void *node,
300 void *insert_begin,
301 void *insert_end
302 ) __attribute__((__nonnull__(6)));
303
304 /**
305 * Removes a node from the linked list.
306 *
307 * If the node to remove is the begin (resp. end) node of the list and if \p begin (resp. \p end)
308 * addresses are provided, the pointers are adjusted accordingly.
309 *
310 * The following combinations of arguments are valid (more arguments are optional):
311 * \li \p loc_next and \p loc_prev (ancestor node is determined by using the prev pointer, overall O(1) performance)
312 * \li \p loc_next and \p begin (ancestor node is determined by list traversal, overall O(n) performance)
313 *
314 * \remark The \c next and \c prev pointers of the removed node are not cleared by this function and may still be used
315 * to traverse to a former adjacent node in the list.
316 *
317 * @param begin a pointer to the begin node pointer (optional)
318 * @param end a pointer to the end node pointer (optional)
319 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
320 * @param loc_next the location of a \c next pointer within your node struct (required)
321 * @param node the node to remove
322 */
323 void cx_linked_list_remove(
324 void **begin,
325 void **end,
326 ptrdiff_t loc_prev,
327 ptrdiff_t loc_next,
328 void *node
329 ) __attribute__((__nonnull__(5)));
330
331
332 /**
333 * Determines the size of a linked list starting with \p node.
334 * @param node the first node
335 * @param loc_next the location of the \c next pointer within the node struct
336 * @return the size of the list or zero if \p node is \c NULL
337 */
338 size_t cx_linked_list_size(
339 void const *node,
340 ptrdiff_t loc_next
341 );
342
343 /**
344 * Sorts a linked list based on a comparison function.
345 *
346 * This function can work with linked lists of the following structure:
347 * \code
348 * typedef struct node node;
349 * struct node {
350 * node* prev;
351 * node* next;
352 * my_payload data;
353 * }
354 * \endcode
355 *
356 * @note This is a recursive function with at most logarithmic recursion depth.
357 *
358 * @param begin a pointer to the begin node pointer (required)
359 * @param end a pointer to the end node pointer (optional)
360 * @param loc_prev the location of a \c prev pointer within your node struct (negative if not present)
361 * @param loc_next the location of a \c next pointer within your node struct (required)
362 * @param loc_data the location of the \c data pointer within your node struct
363 * @param cmp_func the compare function defining the sort order
364 */
365 void cx_linked_list_sort(
366 void **begin,
367 void **end,
368 ptrdiff_t loc_prev,
369 ptrdiff_t loc_next,
370 ptrdiff_t loc_data,
371 cx_compare_func cmp_func
372 ) __attribute__((__nonnull__(1, 6)));
373
374
375 /**
376 * Compares two lists element wise.
377 *
378 * \note Both list must have the same structure.
379 *
380 * @param begin_left the begin of the left list (\c NULL denotes an empty list)
381 * @param begin_right the begin of the right list (\c NULL denotes an empty list)
382 * @param loc_advance the location of the pointer to advance
383 * @param loc_data the location of the \c data pointer within your node struct
384 * @param cmp_func the function to compare the elements
385 * @return the first non-zero result of invoking \p cmp_func or: negative if the left list is smaller than the
386 * right list, positive if the left list is larger than the right list, zero if both lists are equal.
387 */
388 int cx_linked_list_compare(
389 void const *begin_left,
390 void const *begin_right,
391 ptrdiff_t loc_advance,
392 ptrdiff_t loc_data,
393 cx_compare_func cmp_func
394 ) __attribute__((__nonnull__(5)));
395
396 /**
397 * Reverses the order of the nodes in a linked list.
398 *
399 * @param begin a pointer to the begin node pointer (required)
400 * @param end a pointer to the end node pointer (optional)
401 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
402 * @param loc_next the location of a \c next pointer within your node struct (required)
403 */
404 void cx_linked_list_reverse(
405 void **begin,
406 void **end,
407 ptrdiff_t loc_prev,
408 ptrdiff_t loc_next
409 ) __attribute__((__nonnull__(1)));
410
411 #ifdef __cplusplus
412 } // extern "C"
413 #endif
414
415 #endif // UCX_LINKED_LIST_H
416